Datasets:

Trelis

/

big_patent_100k_characters

like 1

The U.S. Government has rights in this invention pursuant to a fellowship awarded the National Science Foundation. BACKGROUND OF THE INVENTION This invention relates to an improvement in a solar powered tracking device which is then used to drive a concentrating solar collector for concentrating solar radiation, and more particularly, it relates to such a device wherein the radiation received by sensing devices containing a volatile liquid results in a vapor pressure which powers the movement of the device to respond appropriately when subjected to solar radiation of the sun. The technology of utilizing solar energy is not new. It has been known for many years that solar radiation may be concentrated with mirrors and with lenses to produce temperatures of 1000° F. and higher. Tracking devices in the past have been powered by electric motors, clockwork mechanisms, hydraulic cylinders, and even locomotive engines. Clockwork mechanisms are precise but they frequently are limited as to the maximum size of the control surface that can be turned. Electric motor systems are probably the most common devices in this field but these systems can be costly and complex. The use of hydraulic or pneumatic pistons and cylinders is much less expensive if a self-contained driving system can be developed that does not rely upon electricity, fuel oil, or other purchased energy sources. Among the prior art patents in this field in U.S. Pat. No. 4,027,651 to Robbins in which a V-shaped receiver is fitted with mirrors and shading devices that direct the solar radiation or, conversely, shield the solar radiation from tubing coils containing a heat sensitive fluid which produces a differential pressure on a piston that in turn causes the apparatus to be adjusted so that it points directly at the sun. In U.S. Pat. No. 4,038,972 to Orrison a parabolic mirror concentrates the solar radiation and tracks the sun by an automatic control based on a light sensing apparatus which signals an electric motor to turn the mirror in whatever direction is needed. In U.S. Pat. No. 4,078,549 to McKeen et al., a mirror facing the sun concentrates the solar radiation and is kept in the appropriate position by a light-sensing mechanism which controls an electric motor that moves the mirror by a chain drive. The present invention is an improvement on the device described in an article by Morrison et al., entitled "Solar Powered Tracking Device", Building Systems Design, Dec./Jan. 1976. The device described in this article comprises a mirror which is parabolic in cross section and has any suitable and convenient length along which at the focus of the parabola is a metallic tube receiving the concentration of radiation striking the mirror and through which flows any suitable fluid which can receive the solar energy. The device is powered to track the sun by means of two hydraulic/pneumatic cylinders whose pistons are fixed to each other in an opposing relationship. The piston rods are joined to each other through a gear rack which is mated to a pinion gear affixed to the axis of rotation of the mirror such that any movement of the gear rack and pinion gear will cause the control surface to rotate about its axis. The two cylinders are powered with the vapor pressure from a refrigerant liquid which forms the working portion of two radiation sensing bulbs containing the liquid and attached to each side of the movable control surface. Appropriate shading devices are located to shade or not to shade the sensing devices from solar radiation when the control surface is not pointed directly at the sun. Only one of the two sensing devices is more exposed to the sun in any given position of the control surface except when it is pointed directly at the sun, in which event both of the sensing devices are partially shaded from radiation. When the control surface is not pointed directly at the sun the more exposed sensing device is heated by the solar radiation to cause an increase in vapor pressure of the refrigerant liquid which in turn causes a corresponding movement of the pistons in the cylinders, and through the gearing arrangement a corresponding movement of the control surface. While this device has many admirable features it does not track the sun with sufficient precision to be acceptable as a practical means for concentrating solar energy. SUMMARY OF THE INVENTION This invention priovides improvements in the basic device described in the Farber article mentioned above. The improvement lies in the radiation sensing device which functions to cause the control surface to be repositioned with respect to the sun with considerable precision. The device of this invention is capable of maintaining the controlled surface at a position which is not more than 0.5° away from alignment with the sun under normal clear sky radiation conditions. The improvements involve a radiation sensing element which is a light weight metal tubing in the form of a loop which includes a large volume reservoir. The loop is such that liquids or vapor can flow in a closed circuit through the reservoir and the connected tubing. An outlet from the loop leads to the pneumatic cylinders which provide the power for moving the control surface. The loop of tubing and reservoir is constructed such that it extends substantially the length of the sensor element and is joined in a heat conductive manner to a thin, rectangular fin which serves to enhance the heat conductivity of the tube and also to shade the large reservoir from solar radiation. The entire loop of tubing and reservoir is enclosed, except at its end portions, by a tubular shield which permits radiation from one direction and prohibits it from another direction. The tubular shield is transparent to radiation in its portion which faces away from the control surface and is opaque to radiation in its portions which faces toward the control surface. This shield also provides protection against convection due to wind and breezes which would reduce the precision of the device in tracking the sun. BRIEF SUMMARY OF THE DRAWINGS FIG. 1 is a plan view of the solar tracking device of this invention. FIG. 2 is an end elevation view of the device of FIG. 1. FIG. 3 is the other end elevation view of the device of FIG. 1. FIG. 4 is a side elevation view of the device of FIG. 1. FIG. 5 is an illustrative view of the device of this invention in operation. FIG. 6 is a schematic illustration of the connection between the pneumatic cylinders and the sensing elements of this invention. FIG. 7 (A,B,C) are illustrative drawings showing how the sensing elements are activated to track the sun with precision. FIG. 8 is a schematic end view of the sensing element of this invention and its connection to the tracking device. FIG. 9 is a perspective view of the sensing element. DETAILED DESCRIPTION With specific reference to FIGS. 1,2,3, and 4 a general understanding of the operation of the solar tracking device can be obtained. Control surface (11) is parabolic in cross section as seen in FIGS. 2 and 3 and extends over a convenient and suitable length as shown in FIGS. 1 and 4. The control surface is supported by rectangular housing (12) having collars (13) (14) attached at each end. Metal tube (15) is supported by the collars and positioned to be along the focus of the parabolic section of the control surface and thus receives the solar radiation striking the control surface and subsequently being reflected to the focus of the parabola. Any suitable energy absorbing fluid may be circulated through tubing (15), such as water, oil, molten salt, etc. Control surface (11), housing (12) and collars (13) and (14) are all fixed to each other and are rotated around the axis of tubing (15) although the tubing does not turn with the other parts but merely fits loosely through collars (13) and (14) resting in bearings (16) fixed to a supporting structure of legs (17) at each end of the device. The legs are adjustable in length so that the entire device can be positioned as closely as possible perpendicular to the rays of the sun. This position will vary depending upon the seasons of the year. Attached to each of the long sides of housing (12) are brackets (18) to which are attached sun shades (19). Radiation sensor (20) is supported on each side of housing (12) below sun shade (19) and is supported by an appropriate number of arms (21) attached to housing (12). The relative positioning of sensors (20) and sun shades (19) as well as the sizes of the two elements depends upon the tracking sensitivity which the operator desires for this device and the details of this will be explained later. At the end of the device which operates at the highest elevation, as seen in FIG. 5, hereinafter referred to as the "head" of the device, there is located the mechanism which turns control surface (11) in its movement in tracking the sun. Two pneumatic cylinders (22) are assembled in an opposing relationship by joining the piston connecting rods (23) to each other through a rack gear (24). Rack gear (24) mates with stationary pinion gear (25) which is fixed to bearing (16). As the pistons in cylinders (22) move to the right or left that movement is transmitted to rack gear (24) and pinion gear (25) to cause control surface (11) and the equipment attached thereto to turn. Each of sensors (20) is connected by tubing (26) to its appropriate cylinder (22) so that pneumatic pressure generated by the fluid in one of the sensors (20) will oppose the pressure generated in the other sensor (22). The connection between tubing (26) and cylinders (22) will be discussed in detail in the description of FIG. 6. In FIG. 5 there is illustrated a general view of the assembly, upon which is mounted the device of this invention, resting on the ground or any other support parallel to the ground indicated at (27) and receiving radiation (30) from the sun. Due to the fact that the north-south axis of the earth rotates in a conical fashion as the earth orbits the sun, the angle at which the sun's rays hit the earth surface varies throughout the year from a smaller angle in the winter season to a larger angle in the summer season. In order to utilize the maximum of the sun radiation which strikes control surface (11) the focal axis of the control surface, represented by the axis of tubing (15) should be perpendicular to the rays from the sun. In FIG. 6 there is a schematic illustration of the connections between the sensors (20) and pneumatic cylinders (22). The tubing (26) coming from one of sensors (20) leads into one of the two cylinders (22) and the tubing (26) from the other sensor (20) leads into the other cylinder (22) to produce opposing forces on the pistons (29). The tubing (26L)) from sensor (20L) leads to the left hand portion of cylinder (22L) and tubing (26R) from sensor (20R) leads to the right hand portion of cylinder (22R). In this way pressure from sensor (20R) pushes both of pistons (29) to the left, and pressure from the sensor (20L) pushes both of pistons (29) to the right. Whatever the balance of forces on pistons (29L) and (29R) may be, the resultant force moves piston rods (23) and rack gear (24), which translates itself into a movement of control surface (11) and its attached equipment. In FIGS. 7 A, B, and C there are shown schematic illustrations of how the tracking device of this operation functions to align control surface (11) with the rays from the sun (30). In FIG. 7 A there is shown control surface (11) and housing (12) to which are joined sun shades (19) and sensors (20) on each side of the control surface. When the control surface (11) is positioned as shown in FIG. 7A directly perpendicular to the sun's rays (30) sun shades (19) are able to keep sensors (20) partially and equally shaded as shown in cross hatched areas (31). In this mode the fluid in sensors (20) is at the same temperature, and thereby at the same vapor pressure, which produces a balanced pressure on the two pistons to which the sensors are connected as described previously with respect to FIG. 6, and no movement of surface (11) is produced. In FIG. 7 B the rays of the sun (30) are not perpendicular to control surface (11) as indicated by angle (41). In this mode the sensor (20R) is not shaded from radiation by sun shade (19R) while sensor (20L) is shaded by sun shade (19L). In this situation the fluid in sensor (20R) becomes heated by radiation from the sun while the fluid in left hand sensor (20L) is not subjected to that heating. Accordingly the vapor pressure rises in right hand sensor (20R) and an unbalanced pressure is produced in the pneumatic cylinders connected to both sensors (20) which produces a movement of the rack gear which joins the two pistons in those cylinders and that movement is translated into a rotation of control surface (11) and its associated equipment to where it is then aligned with the solar radiation (30) as shown in FIG. 7 A. In FIG. 7 C there is shown exactly the opposite condition to that just described with respect to FIG. 7 B. The same operations in reverse will function to bring the apparatus back into alignment with the sun's rays. In this instance sensor (20L) is heated producing an excess of pressure over that produced by sensor (20R) and a corresponding movement of the gears returns control surface (11) to the position shown in FIG. 7 A. In FIGS. 8 and 9 there are illustrated the details of radiation sensors (20) from the previous description. A suitable number of supporting arm (21) are attached to housing (12) by any convenient means to support sensor (20) as shown in FIG. 4. Bracket (32) is adjustably attached to arm (21), for example by wing nut clamp (33) in order to permit adjustment up or down arm (21). Bracket (32) serves to support the three components of the sensor; namely, tubing (34), fin (35), and reservoir (36). As seen in FIG. 9 these three components of the sensor form a loop in the tubing (34) including reservoir (36) in that loop. Fin (35) is a heat conductive material, preferably a metal, which serves to enhance the ability of tubing (34) to absorb radiation from the sun and to cool when tubing (34) is in the shade. Reservoir (36) serves the purpose of maintaining a large volume of liquid inside of tubing (34) and is positioned to maintain the entire loop substantially full of liquid. Tubing (26) leads directly to pneumatic cylinders (22) as described previously. Surrounding the entire loop of tubing (34), fin (35), and reservoir (36) is an enclosure which serves as a windshield. In order to maintain the highest precision of the apparatus of this invention the windshield should not be in contact with any of the three components just mentioned and thus should be supported by brackets (32). The windshield is made of two parts, the portion (37) facing away from control surface (11) being completely transparent to solar radiation and the portion (38) facing toward control surface (11) being opaque to solar radiation. There are many suitable plastic and/or glass materials which will serve the purpose of being transparent to radiation and will serve conveniently for portion (37). Portion (38) is made of any convenient, lightweight, material such as aluminum, wood, etc. Inside surface (39) of portion (38) is made to be reflective so that any radiation reaching that surface will be reflected in a normal manner. Outside surface (40) is made to be opaque to solar radiation, and preferably not reflective to any great degree, nor should it absorb any great amount of heat. Tubing (34) and fin (35) are preferably painted with a flat black paint in order to absorb as much heat as possible. Reservoir (36) is made of such a size and placed so that it will be shaded from radiation approaching from above by fin (35) and thereby its large volume of liquid will not undergo the same extremes of temperature that will be experienced in tubing (34). The reason for having portion (38) with two different types of surface is that, in some extreme positions of the apparatus of this invention, it is conceivable that the solar radiation would be almost parallel to fin (35) and the responsiveness of the sensor would be reduced. By making surface (39) reflective and setting it at an angle to fin (35) the radiation will be reflected to the underneath side of fin (35) which will thereby be capable of absorbing sufficient heat to provide the necessary responsiveness for this sensor. Similarly outside surface (40) should be opaque to radiation because, in certain extreme positions of the apparatus of this invention, the radiation might pass underneath control surface (11) and strike the temperature sensitive elements when that is not desirable. The principal purpose of the enclosure comprising portions (37) and (38) is to function as a shield against wind and breezes which might cause cooling by convection of the elements of the sensor and thereby disrupt its proper functioning. Although it is feasible to encapsulate these elements completely with a windshield of large volume, it is preferable to employ a small volume with the two ends (39) open to the atmosphere to facilitate cooling of the sensor elements when they have been moved into position where they are partially shaded. While it us conceivable that wind might be blowing in the direction longitudinal to the windshield and thus blow through the length of the enclosure, this same effect will apply to both sensors and thus will substantially balance each other. Tubing (34), fin (35), reservoir (36), and bracket (32) are shown as being welded or soldered to each other to form the necessary connections. However, any suitable mechanical means of connection may be utilized. It is necessary that tubing (34) and (35) be joined in some manner which will provide maximum heat conduction in order to transmit whatever heating or cooling effects that are received by fin (35) immediately and completely to the fluid in tubing (34). It is also important that reservoir (36) be placed in the tubing loop at the end which will be at the highest elevation, that is near the head of the machine. The reason is that this will insure that substantially all of the tubing loop will be filled with liquid contained in the reservoir. This will maximize the amount of liquid in tubing (34) that is attached to fin (35) and subjected to solar radiation, which in turn provides the best responsiveness of the sensor to the presence or absence of radiation. The device of this invention is capable of maintaining the control surface within 0.5° of alignment with the sun's rays under normal clear sky radiation conditions. Furthermore, it is entirely capable of quickly responding to accomplish adjustment from its most westward position at sundown to the most eastward position at dawn the next day when irradiated by the sun. If the device (for example in FIG. 2) is rotated to the extreme westward position, the morning sun at the next dawn will contact the east sensor (20) but will only contact the opaque surface (40 in FIG. 8) of the west sensor (20). In this situation, which is a more extreme version of that shown in FIG. 7 B, radiation will cause heating of the sensor and the liquid contained in the sensor on the east side of the apparatus, but not the elements and the liquid in the sensor on the west side of the apparatus. This will cause an imbalance in vapor pressures forcing pistons in pneumatic cylinders toward the west, which because of the gearing arrangements tilts the control surface to the east until the east sensor is partially shaded and the control surface is aligned with the solar radiation as shown in FIG. 7 A. Because of the difficulties of maintaining appropriate lubrication, it has been found that the cylinders (22) and pistons (29) of the rolling diaphragm type, rather than those in which piston rings are employed to seal against leakage, perform heat, however any arrangement which incorporates positive vapor seal and low friction characteristics may be employed. In cylinders having the rolling diaphragm arrangement there is no sliding frictional contact during the movement of the piston. The diaphragm in modern devices is entirely capable of functioning, under the pressures normally experienced in this tracking device for long periods of time. Fluids employed in this device for producing the necessary vapor pressure are preferably those which can provide a vapor pressure of at least 5 psig at the minimum design temperature setting and provide increasing pressure up through a maximum design temperature setting, the pressure at the upper temperature limit being not more than about 200 psig. The increase in pressure over this range of temperatures should be reasonably constant so that no particular temperature level provides any peculiarities in pressure changes. The fluid should of course be compatible with the materials employed in the cylinders and in the sensor, and also be nontoxic, nonexplosive, and readily available. In general, there are many refrigerants which satisfy these conditions and they may be chosen from American Society of Heating Refrigerating, and Air Conditioning Engineers Handbook, however, any fluid which possesses the aforementioned characteristics may be utilized. While the invention has been described with respect to certain specific embodiments, it will be appreciated that many modifications and changes may be made by those skilled in the art without departing from the spirit of the invention. It is intended, therefore, by the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention.

A solar powered tracking device for controlling radiation exposure of surfaces, wherein solar radiation increases the vapor pressure of a liquid in a sensing device and the vapor pressure acts on opposed pneumatic cylinders to produce mechanical movement of the controlled surface to track the sun with a maximum deviation of not more than 0.5° under normal clear sky radiation conditions.

BACKGROUND OF THE INVENTION 1. Field of the Invention A rotary sliding vane compressor having means for urging the vanes outwardly and maintaining the vane tips in engagement with the cylinder wall during start-up and at rotational low speeds. 2. Description of the Prior Art Burnett U.S. Pat. No. 3,376,825 describes a rotary vane compressor having a leaf type spring element between the radially inner portion of the vane and the bottom of the vane slot. The spring is designed so that during high speed operation, when centrifugal forces are sufficient to maintain the vane tips in contact with the cylinder wall, the same centrifugal forces will cause the spring to collapse against radially inner edges of the vane and thus become ineffective as a spring element. English U.S. Pat. No. 1,984,365 describes a rotary sliding vane compressor having a leaf type spring in the bottom of the vane slot and having its convex side in contact with the central region of the vane edge which is essentially linear. Kenney et al. U.S. Pat. No. 2,045,014 also discloses a leaf spring with its ends embedded in the bottom of the vane. Fuehrer U.S. Pat. No. 3,191,503 shows a sliding vane fluid handling apparatus which uses O-rings of elastomeric material underneath the vanes to bias the same outwardly. Gibson et al. U.S. Pat. No. 1,857,276 is representative of a large number of prior art references which utilize fluid pressure underneath the vanes to maintain the vane tips in engagement with the cylinder wall. SUMMARY OF THE INVENTION This invention relates in general to rotary sliding vane compressors and more particularly to an effective means for biasing the vanes radially outwardly to maintain the vane tips in sliding engagement with the cylindrical wall of the rotor chamber which forms the gas working space. Although rotor sliding vane compressors are known in a great many forms, the description herein is directed to a conventional type in which a rotor is provided with a plurality of extensible vanes each received with a generally radially oriented or canted vane slot in the rotor. The rotor is received within a cylindrical chamber or stator and mounted such that its axis is offset with respect to the cylindrical stator axis, thus providing a generally crescent shaped gas working space. The rotor is in sliding contact with a portion of the cylindrical wall, and this contact point divides the low pressure side from the high pressure side. An inlet port communicates with one side of the gas working space and a discharge port communicates with the opposite side. Gas is trapped between adjacent vanes and carried around through the compression zone. The volume of each pocket or compartment, as defined between adjacent vanes and the rotor and stator surfaces, becomes smaller as it approaches the discharge port thus compressing the gas trapped therein. A problem is often encountered in operating compressors of the type described above in that the vanes sometimes will not maintain their tips in engagement with the cylindrical stator wall under all conditions. This is especially true at start-up when the rotor is travelling at low rotational velocities. The centrifugal force which would normally tend to throw the vanes outwardly is not sufficient to overcome the vacuum created when the vanes begin to move their most radially inward portion to the point directly opposite the contact point. The latter may be regarded as a dash-pot effect and is extremely powerful in resisting the outward thrust of the vanes. Several techniques have been used in the prior art to hold the vane tips in engagement with the cylindrical wall. Basically, these may be divided into two categories: mechanical (such as spring) and hydraulic or pneumatic. The mechanical springs used may take many forms, such as the leaf springs described in Burnett, Kenney et al and English, or helical (coil) springs. Just as common are the hydraulic or pneumatic means such as described in Gibson et al. In the present invention, a mechanical element is employed which overcomes many of the disadvantages of the springs heretofore known. It is difficult to obtain any significant service life when using a leaf or coil spring in the typical rotary compressor environment. With each revolution of the rotor the spring is compressed and released. Since the compressors operate at several hundred R.P.M., it is apparent that the springs undergo flexing at unusually high rates and thus are subject to fatigue failure. The objective of the present invention is to minimize the amount of flexure involved, especially the total travel distance for each compression and extension of the spring. The present invention employs a novel, three-layer composite spring having (1) a metal portion in contact with the vane to provide the necessary rigidity, (2) a bonded rubber or elastomeric component to extend the life of the metal element, and (3) a bonded fabric wear surface in contact with the bottom of the vane slot to provide resistance to abrasion from rubbing contact with the vane slot and consequent cutting or nicking of the rubber component. Still another aspect of the invention is the superior load distribution which is accomplished by mating the curved vane bottom with a bridge-like rubber/metal composite spring assembly. Further, the surface provided by the metal spring, in combination with the rubber or elastomeric element, is effective in dampening noise during operation. The fabric wear surface extends the useful life of the composite assembly, thus decreasing the need for expensive maintenance due to failure of the unit. The assembly is compact, inexpensive to install, and requires no special modifications to conventional compressor parts. Other advantages to this system include the fact that since no hydraulic means are provided for maintaining the vanes extended, it is not necessary to provide either a lubricant pump or other means for collecting and distributing oil and/or refrigerant to the undervane spaces. It also provides instant pumping action upon start-up, reduces hammering and consequent vane wear caused by delayed movement of the vane to the extended position, eliminates reverse rotation at rotor shutdown often caused by equalization of pressures between the high and low sides of the compressor rotor, and results in lower discharge gas temperature. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional view of a rotary sliding vane compressor constructed in accordance with the principles of the present invention; FIG. 2 is a cross sectional view taken along the plane of line 2--2 of FIG. 1; FIG. 3 is a greatly enlarged sectional view showing the relationship of the resilient element with respect to the vane and the vane slot; FIG. 4 is a partial perspective view of the resilient element; FIG. 5 is a cross sectional view taken along the plane of 5--5 of FIG. 3; and FIG. 6 is a view similar to FIG. 5 showing the resilient element in its fully flexed position. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, particularly to FIGS. 1 and 2, there is shown a typical rotary compressor of generally conventional design including a stator housing 10 comprising a cylinder block 12 having a circular bore extending therethrough to provide a cylinder wall 14, a front end plate 16, and a rear end plate 18. Within housing 10 there is provided a rotor 20 connected to and driven by drive shaft 22. The rotor is eccentrically mounted within the cylinder 14 so that it is in close running contact with the cylinder wall 14 at a contact point 28 and forms a crescent-shaped gas working space or compression cavity 26. The rotor is provided with a plurality of vane slots 30 each having a bottom surface 32 and receiving vanes 34 which are adapted to reciprocate within each vane slot with their upper edges 34a in continuous engagement with cylinder wall 14. It may be seen that the lower sides of each slot, the bottom edge 34b of the vanes 34, and the bottom of the vane slot 32 define what will be referred to as the "undervane space", designated 35. Suction gas is admitted to the compression cavity 26 through connection 36 and passage 38. Gas is discharged through a series of openings 42 (adjacent the contact point) which are covered by reed-type discharge valves 44, limited by valve stops 45. Discharge gas flows into chamber 50 and then through passage 52 in rear plate 18. Located between the lower edge of each vane and the bottom of the vane slot 32 is a resilient element 60, shown in partial perspective view in FIG. 4, which includes a first component in the form of a flat spring 62 formed of spring steel or other suitable alloy having good wear characteristics and adapted to withstand a large number of flexures at high frequency without failure. Bonded to the spring element is an elastomeric damper 64 having enlarged, spherically-shaped terminal portions 65 and a central section 66 having a relatively thin cross-sectional area as compared to the end portions. The spherically-shaped ends 65 of damper 66 are adapted to seat in complementary sockets 67 formed in the ends of vane slot 32. This arrangement provides pivot points at each end to minimize abrasion of the ends of resilient element 60 against the bottom of the slot, and further operates to maintain the resilient element in the proper location within the vane slot during assembly and while the pump is operating. Bonded to the peripheral surface of the elastomeric damper 64 is a wear layer 68, formed of woven nylon fabric, or other suitable fabric having good wear characteristics and adapted to stretch elastically at high frequency without failure. As best shown in FIG. 5, the bottom edge 34b of each vane is curved thus forming a convexly shaped edge engageable with the flat spring component 62 of the resilient element 60. When the vanes are fully extended, as shown in FIG. 5, the resilient element 60 lies flat across the entire vane slot region. At this point the resilient element is completely unflexed; and no portion thereof is under either compression or tension. As best shown in FIG. 6, the resilient element 60, after engagement with convexly shaped edge 34b, is in a condition where the resilient element assumes the same general contour as the bottom edge, and the elastomeric portion is forced downwardly so that the central region 66 is closely spaced from the bottom of the vane slot. The spherically-shaped terminal portions 65 are displaced outwardly in contact with the bottom of the vane slot, providing a rubbing contact between the surface of the vane slot and the terminal portion 65 surfaces. At this point, the spring is in a condition to bias the vane upwardly against the inside cylinder wall or stator, and this will result in immediate pumping action upon start-up prior to the generation of enough centrifugal force to hold the vanes in contact with the cylinder wall. It will be apparent that a long term, high frequency flexing of the resilient element 60 will subject the terminal portions 65 to severe abrasion, particularly in the terminal portion 65 surfaces in rubbing contact with the bottom of the vane slot. The addition of the improved wear layer 68 in the form of a woven fabric protects the terminal portion 65 from abrasion and markedly extends the service life. While a variety of elastomeric compounds may be used in making element 66, they should be resistant to the oil-refrigerant environment in which they must operate in a refrigeration/air conditioning application. Suitable materials would include urethane, nitrile, epichlorohydrin, fluorocarbon and silicone rubbers. A number of woven fabric materials may be used in the forming of the wear layer 68, however, it is necessary that such materials be elastic in order to conform to the surfaces during deformation of the composite spring while in use. The preferred materials will stretch at least 25%, preferably greater than 50%, in at least one direction with a high degree of recovery in order to be suitable for the purposes of this invention. A number of such stretch fabrics are commercially available including nylon, polyester and the like, which have the necessary stretch properties together with high wear character and resistance to attack by oil-refrigerant environments in which those pumps are operated. A suitable fabric for the purposes of this invention is a nylon fabric obtained from Stern and Stern Textile Corporation as pattern A-3274/2 and having a thread count of 104 × 70, weighing 6 to 6.7 oz. per square yard. This fabric is stretchable only in the filler direction of the weave, with a grab tensile of 180 psi. and an elongation of 100%. In the warp direction the fabric has a grab tensile value of 400 psi. The fabric is pre-treated on the surface with a resorcinol-formaldehyde resin to provide improved adhesion between the fabric and the rubber component. It is essential that the fabric when applied to the surfaces of the composite spring be oriented so that the stretch (filler) direction of the fabric coincides with the longitudinal axis of the resilient element. The fabric will then stretch and not be torn loose by shear stresses during repeated flexing of the composite spring structure. The composite spring structure according to this invention was formed by compression molding. First the mold cavity was lined with the fabric, pre-cut and oriented in the mold with the stretch (filler) direction of the weave along the longitudinal axis. A molded preform of the rubber component was then placed in the mold cavity. The leaf spring component, coated with a suitable adhesive such as Ty Ply BN, available from Hughson Chemical Corp., was placed in the mold and the mold was closed, placed under clamping pressure and heated to form the part and cure the rubber and adhesive components. When cooled and removed from the mold the resulting composite spring structure was complete. It will be apparent that the molding operation described is one of many common to the rubber manufacturing art and many variations will thus be possible and even desirable for speed and improved economy of manufacture. While this invention has been described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not by way of limitation; and the scope of the appended claims should be construed as broadly as the prior art will permit.

A rotary sliding vane compressor having means for biasing the vanes outwardly. Such means include a resilient element located in the lower portion of the vane slot and engaging a convexly shaped edge on the vane. An improved wear surface on the resilient element at the area of contact with the vane slot provides enhanced service life. The flexing action of the resilient member ensures that the vanes will be moved outwardly during the expansion phase of rotor travel.

DESCRIPTION OF THE PRIOR ART The generation of images on a data carrier such as a paper sheet or web by means of electrostatic copying is well known. In such apparatus, a photoconductive member is charged to sensitize the surface thereof, and the charged member is exposed to a light image of the document to be reproduced. The resulting exposure of the sensitized surface selectively discharges the charge thereon and records an electro-static latent image on the surface which corresponds to the informational areas contained upon the surface of the original document being reproduced. Development of the electro-static image is achieved by transporting developer materials such as dyed or colored heat settable plastic powders called toner particles into contact with the latent image such that the attractive forces thereof cause the toner particles to transfer from the carrier media onto the sensitized surface. Although numerous techniques are utilized for applying the developer material to the latent image, one of the most popular techniques is to mix the toner particles with carrier beads or granuals which can be magnetically picked up and transported to a position proximate the sensitized surface of the photoconductive member. In passing by such surface, the greater attractive force of the charged surface exceeds the triboelectrical force with which the particles adhere to the beads and most of the toner particles are removed and become electro-statically attached to the sensitized surface. The carrier beads and remaining toner particles are then returned to a reservoir for reuse. However, in many device configurations, as the toner and carrier particles fall into the reservoir, they create a downward movement of air which tends to slightly pressurize the reservoir and cause toner dust to be blown out of the reservoir and through the gap between the developer and the photoconductive surface. This dust may then contaminate the photoconductive surface as well as other portions of the machine causing improper operation and increased maintenance problems. One attempt to deal with a related problem is disclosed by Tsukamoto et al in U.S. Pat. No. 4,155,329. However, the Tsukamoto solution concerns itself more with the air flow problem created by the particle carrier transport mechanism than by the problem created by the carrier particles themselves as they are returned to the reservoir and fails to suggest a solution to the latter mentioned problem. SUMMARY OF THE PRESENT INVENTION It is therefore a primary objective of the present invention to provide an improved means for reducing toner dust contamination in electrophotographic printing apparatus. Still another object of the present invention is to provide a simple and inexpensive mechanism which can be added to existing electro photographic systems to seal the toner reservoir and reduce toner leakage. In accordance with a presently preferred embodiment of the present invention, the developer unit of an electro photographic system is modified by attaching a thin strip of resilient material in cantilever fashion to the lip of the developer housing or the toner carrier return side of the toner reservoir so as to resiliently extend to the developer roller. The strip provides a flexible closure which is pliable enough to be opened slightly by the carrier particles as they are delivered back into the reservoir but which is resilient enough to spring back into a closed position against the roller when no developer mix is being returned to the reservoir. Dust created by carrier/developers particles falling into the reservoir is thus contained within the reservoir and prevented from leaking into other portions of the system. An advantage of the present invention is that it provides an inexpensive solution to the problem of toner contamination. Another advantage of the present invention is that it provides a flexible developer unit seal and which is self-actuating and includes no complicated mechanical components. Still another advantage of the present invention is that it provides a toner reservoir sealing device which can easily be retrofit to existing electrophotographic systems. These and other objects of the present invention will no doubt become apparent to those of skill in the art after having read the following detailed description of the preferred embodiment. IN THE DRAWING FIG. 1 is a partially broken perspective view showing an electro-photographic developer unit including a flexible seal in accordance with the present invention. FIG. 2 is a cross section taken along the lines 2--2 of FIG. 1; FIG. 3 is an exploded view further illustrating the flexible seal shown in FIGS. 1 and 2; and FIG. 4 is a cross section taken through an alternative embodiment including a flexible seal in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2 of the drawing, a developer unit 10 and photosensitive drum 12 forming parts of an electro-photographic system are shown in partially broken form. The drum 12 has a photoconductive surface 14 entrained about and secured to the exterior circumferential surface of a conductive substrate in a manner well known in the art. Mounted beneath drum 12, the developer unit 10 includes an outer housing 16, a developer roller 18, a transport roller 20 (FIG. 2) and a pair of mixer spindles 22 and 24. Affixed to the inner side wall of housing 16 is a doctor blade 26 having an edge 28 which is disposed closely adjacent to developer roller 18 so as to define a gap therebetween that regulates the thickness of developer material allowed to adhere to and be carried by developer roller 18. Also disposed within housing 16 is a guide plate 29 which serves to return carrier and toner particles to the bottom of the container as they are removed from drum 18 by doctor blade 26. The rollers 18 and 20 form magnetic brushes which consist of cylinders 30 and 32 that are rotatably mounted at their ends to housing 16 and are made of a suitable non-magnetic material such as, for example, brass, aluminum, copper or stainless steel. Disposed within the respective cylinders are permanent magnets 34 and 36 which are appropriately arranged and have magnetic strengths so as to create magnetic fields that will attract magnetic carrier beads or similar carrier particles contained within the reservoir formed by the lower portion of housing 16 and hold such beads in contact with the portion of the periphery of the cylinders disposed within the magnetic fields. This of course allows roller 20 to pick up the beads and triboelectrically attach toner powder and transport it upwardly into close proximity to drum 12. As will be noted in FIG. 2 of the drawing, the edges of housing 16 surrounding the communicative opening 38 form lips 40 and 42 which are turned back so as to be generally tangent to and conform as close as possible to the surface of drum 12. The lips are however slightly separated from the drum surface so as not to interfere with the turning of the drum or the developer material carried thereby. One of the problems associated with this type of structure is that as the developer material, i.e., the beads and excess toner powder, are carried past the opening 38 and deposited back into the reservoir 44 as indicated at 46 the falling carrier beads and toner material cause air within the reservoir 44 to be displaced and moved around such that an upward flow of toner dust may be caused to be inadvertantly generated in the passage 46 and perhaps even be discharged from the housing by pushing between lip 42 and roller 12. In order to avoid such discharge, the present invention provides an elongated strip or ribbon 50 of flexible material which is affixed to lip 42 by means of a suitable adhesive or the like and is bowed downwardly along its transverse dimension so that when the system is at rest, the opposite unattached edge resiliently bears against the surface of drum 18. As is perhaps better illustrated in FIG. 3 of the drawing, whereas the edge 52 of strip 50 normally bears against the surface of drum 18 to seal the reservoir 44 closed, as the carrier beads (illustrated at 54) fall away from the surface of drum 18 they contact the upper side of strip 50 and cause it to bow and move edge 52 downwardly forming a return slot 56 through which the material may return to the reservoir. The strip 50 thus forms a floating seal which effectively seals the toner reservoir and prevents blowby of any toner dust generated therein. In the preferred embodiment, the strip 50 is a thin plastic member which is resilient enough to spring into engagement with drum 18 but which may be easily deflected away from the drum surface by the falling carrier beads. The film could be made of any of several types of plastics, or could even be comprised of thin sheet metal material or the like. Although the dust blow out problem is of particular concern in the case where the facing surfaces of drum 12 and roller 18 move in the same direction, there is also a somewhat lesser problem created in the case where the drum and developer roller are rotated such that their surfaces move in opposite directions, as illustrated at 118 and 112 respectively in FIG. 4. In this case, the strip of film 150 is affixed to the lip 140 on the particle return side of the opening in housing 116 and is bowed against the surface of drum 118 in a manner similar to that depicted in FIGS. 2 and 3. As in the previously described embodiment, beads carried by the roller 118 will deflect strip 150 out of their way as they fall from the roller surface and procede back into the reservoir via guide plate 129. It will therefore be appreciated that by placing a flexible and resilient strip on the carrier particle return side of the developer roller, an extremely simple but effective means can be provided for reducing contamination which would otherwise deteriorate the background and image carried upon the surface of the developer drum. Although the present invention has been illustrated in terms of a simple, flexible strip adhesively affixed to the housing of the developer unit, it will be appreciated that similarly configured flexible members could be similarly attached using other means to achieve the same objective. It is therefore intended that the following claims be construed as covering all such alterations and modifications as fall within the true spirit and scope of the invention.

The present invention relates generally to electro-photographic printing apparatus and more particularly, to a flexible seal means for reducing leakage of toner particles from the developer unit.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention is related to Enhancement Mode Field Effect Transistors, EMFETs, and Depletion Mode Field Effect Transistor, DMFETs, such as IGFETs, JFETs, MESFETs, MODFETs, HEMTs and so forth, for synchronous rectifier circuits, especially EMFETs or DMFETs with novel structures replacing conventional Static Shielding Diodes, SSDs. According to this invention, traditional SSDs in EMFETs or DMFETs may be replaced with polarity reversed (comparing with traditional SSD) SSDs, Schottky Diodes, or Zener Diodes, or face-to-face/back-to-back coupled Schottky Diodes, Zener Diodes, Fast Diodes, or Four Layer Devices such as DIAC or TRIAC such that conventional functions are preserved and need only to consider the amplitude of the reverse biased voltage for proper semiconductor operating voltage. As shown in FIG. 2 (E) or (F), the amplitude of the reverse biased operating voltage, i.e. Zener Voltage, may be configured according to the needs. The set Zener voltage would be higher than the DC output voltage in actual applications according to this invention. That is, the voltage of conventional SSD in an EMFET or a DMFET is higher than the AC voltage at input side, but the Zener voltage of the polarity reversed coupling Zener Diode is higher than the DC output voltage. According to such design philosophy of this invention, half-wave synchronous rectification may be achieved with a single EMFET or DMFET in coordination with auxiliary circuits, and full-wave synchronous rectification may be achieved with two EMFETs or DMFETs in coordination with auxiliary circuits. Hence, functions of high efficiency synchronous rectification may be achieved. [0003] 2. Description of the Related Art [0004] FIG. 3 shows a circuit of a conventional single ended forward synchronous rectifier, SR. In this figure, FET V 1 is responsible for rectification while FET V 2 is responsible for freewheeling. In operation, when the secondary voltage Us is at the positive half cycle, FET V 1 closes and FET V 2 opens, and FET V 1 acts as a rectifier; when the secondary voltage Us is at the negative half cycle, FET V 1 opens and FET V 2 closes, and FET V 1 acts as a free-wheel. The conductive power waste of FET V 1 and FET V 2 , and the driving power waste of the gates produce the main power waste in the synchronous rectifier circuit. Such scheme comes with the following drawbacks: 1. As far as the power waste is concerned, the power lost due to the follow current results in lower efficiency of synchronous rectification. 2. As far as the cost of material is concerned, EMFETs required for synchronous rectification raises the cost of manufacture. SUMMARY OF THE INVENTION [0007] In order to provide semiconductor devices, which may elevate the efficiency of rectification, this invention is proposed according to the following objects. [0008] The first object of this invention is to provide semiconductor devices that eliminate the drawback of high power consumption of conventional synchronous rectifiers utilizing diodes, such as Schottky diodes. [0009] The second object of this invention is to decrease the cost of manufacture due to EMFETs or DMFETs used for synchronous rectification. [0010] In order to solve the problem of high power consumption in conventional rectifiers and voltage regulation systems, the present invention possesses the following characteristics: 1. Unlike the manufacture process of conventional EMFETs or DMFETs, the polarity of single parasitic diode, SSD, is reversed, or the conventional SSD is replaced with two of face-to-face/back-to-back coupled diodes, i.e., in the manufacture process of EMFETs or DMFETs, coupling characteristic structures of the Lus Semiconductors between drain node and source node shown in FIG. 2 . 2. If no parasitic diodes exist in conventional EMFETs or DMFETs, the characteristic structures shown in FIG. 2 , their permutations and combinations, and even snubber circuits may also be externally coupled between the drain nodes and source nodes to construct the Lus Semiconductors. 3. The Lus Semiconductors in the present invention may also be applied in conventional PWM and PFM power systems. Rectifier diodes may be replaced with Lus Semiconductors and the efficiency may be improved. [0014] According to the defects of the conventional technology discussed above, a novel solution, the Lus Semiconductor, is proposed in the present invention, which provides higher efficiency in synchronous rectification. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 shows the structures of an N-Channel EMFET or DMFET and a P-Channel EMFET or DMFET of the Lus Semiconductor according to the present invention. [0016] FIG. 2 shows characteristic circuit structures of the Lus Semiconductor coupled between the drain and source of the EMFET or DMFET shown in FIG. 1 . [0017] FIG. 3 shows a circuit of a conventional single ended forward synchronous rectifier. [0018] FIG. 4 shows the symbols for N-Channel and P-channel Lus Semiconductors. [0019] FIG. 5 shows one embodiment of full-wave synchronous rectifier and voltage regulation circuit utilizing EMFETs according to the present invention. [0020] FIG. 6 shows one embodiment of half-wave synchronous rectifier and voltage regulation circuit utilizing an EMFET according to the present invention. [0021] FIG. 7 shows one embodiment of full-wave synchronous rectifier and voltage regulation circuit utilizing DMFETs according to the present invention. [0022] FIG. 8 shows one embodiment of half-wave synchronous rectifier and voltage regulation circuit utilizing a DMFET according to the present invention. DETAILED DESCRIPTION OF THE INVENTION [0023] FIG. 1 shows the structures of an N-Channel EMFET or DMFET 100 and a P-Channel EMFET or DMFET 200 of Lus Semiconductor according to the present invention. FIG. 2 shows several characteristic circuit structures 101 of Lus Semiconductor that may be coupled between the drain nodes and the source nodes of EMFETs or DMFETs shown in FIG. 1 . A pair of face-to-face coupled Schottky diodes and a pair of back-to-back coupled Schottky diodes are shown in FIG. 2 (A) and FIG. 2 (B) respectively, and each of the two may be then coupled to the drain node and the source node of the EMFETs or DMFETs. A pair of face-to-face coupled SSDs and a pair of back-to-back coupled SSDs is shown in FIG. 2 (C) and FIG. 2 (D) respectively, and each of the two may be then coupled to the drain node and source node of the EMFETs or DMFETs. A pair of face-to-face coupled Zener diodes and a pair of back-to-back coupled Zener diodes are shown in FIG. 2 (E) and FIG. 2 (F) respectively, and each of the two may be then coupled to the drain node and source node of the EMFETs or DMFETs. FIG. 2 (G) shows a pair of face-to-face coupled Schottky diode and Zener diode, which may then be coupled to the drain node and the source node of the EMFETs or DMFETs. FIG. 2 (H) shows a pair of face-to-face coupled Schottky diode and SSD, which may then be coupled to the drain node and the source node of the EMFETs or DMFETs. FIG. 2 (I) shows a pair of face-to-face coupled Zener diode and fast diode, which may then be coupled to the drain node and the source node of the EMFETs or DMFETs. FIG. 2 (J) shows a DIAC four layer semiconductor and FIG. 2 (K) shows a TRIAC four layer semiconductor, each of the two may then be coupled to the drain node and the source node of the EMFETs or DMFETs. The characteristic circuit structures 101 shown in FIG. 2 (A)˜(K), their permutations and combinations and snubber circuits may all be coupled to the drain node and the source node of the EMFETs or DMFETs and Lus Semiconductors 100 , 200 are thus constructed. With the characteristic circuit structures 101 shown in FIG. 2 (A)˜(K), their permutations and combinations and snubber circuits, high efficiency rectification and voltage regulation may be achieved, with a single EMFET or DMFET. Comparing with the structures of a conventional N-Channel EMFET or DMFET or a conventional P-Channel EMFET or DMFET, one can tell that they are the totally different from the characteristic circuit structures of the Lus Semiconductors. [0024] FIG. 3 shows a circuit of a conventional single ended forward synchronous rectifier. Its operations were described in the description of the related art and will not be discussed here for conciseness. [0025] FIG. 4 shows the symbols for N-Channel and P-channel Lus Semiconductors wherein FIG. 4 (A) is an N-Channel Lus Semiconductor and FIG. 4 (B) is a P-Channel Lus Semiconductor wherein the P junction is the input pole, the N junction is the output pole and the G (Gate) is the control pole. The GN voltage may control the voltage drop between the P junction and the N junction such that the purpose of gate controlled voltage drop may be achieved. [0026] FIG. 5 shows one embodiment of full-wave synchronous rectifier and voltage regulation circuit utilizing EMFETs according to the present invention. In operation, while the voltage at node 8 of the first secondary winding of the high frequency transformer 300 is at positive half cycle, the voltage at node 11 of the secondary winding is also at positive half cycle. The positive voltage at node 11 flows through diode D 4 and voltage dividing resistors RG and RH. Thus the GN voltage of the Lus Semiconductor 100 a equals to the voltage drop between the two ends of the voltage-dividing resistor RG. Because the RDS of the EMFETs of the Lus Semiconductor 100 a is quite small, for example, RDS=5 mΩ. If the current through RDS is 10 A, then the voltage drop between the two ends of RDS is VDS=0.005(Ω)×10 (A)=0.05V. Let the saturation voltage of the diode of the characteristic circuit 101 be VF=0.7V, comparing VDS with VF, the diode of the characteristic circuit can be found open, thus the voltage drop between the two ends of the voltage dividing resistor RG conducts the drain and source of the Lus Semiconductors 100 a . The positive half cycle AC voltage at node 8 passes through the drain and source of the Lus Semiconductor 100 a and a π-type filter constructed with a filter capacitor C 2 , an inductor L 1 and a filter capacitor C 3 , thus becomes DC output voltage Vo. While the AC voltage at the node 10 of the first secondary winding of the high frequency transformer 300 is at positive half cycle, the voltage at node 13 of the secondary winding is also at positive half cycle. The positive voltage at node 13 flows through diode D 5 and voltage dividing resistors RG and RH. Thus the GN voltage of the Lus Semiconductor 100 b equals to the voltage drop between the two ends of the voltage-dividing resistor RG. Because the RDS of the EMFETs of the Lus Semiconductor 100 b is quite small, the voltage drop between the two ends of the voltage-dividing resistor RG conducts the drain and source of the Lus Semiconductors 100 b . The middle node of the second secondary winding is at node 12 which is also coupling to node N, thus formed a complete gate controlled circuit. The operation is identical to that while the AC voltage at the node 8 of the first secondary winding of the high frequency transformer 300 is at positive half cycle. Because those two half-cycle circuits are commonly connected at node N, full-wave rectification may be achieved. While the output voltage Vo is higher than a pre-defined voltage, an adjustable precision shunt regulator integrated circuit IC 1 may be activated, and meanwhile the collector and the emitter at the output side of a photo coupler Ph 0 may be conducted that decreases the duty cycle of the output wave of the PWM control circuit and lower the output voltage Vo to the predetermined voltage; while the output voltage Vo drops, IC 1 deactivates and increase the duty cycle of the output wave of the PWM control circuit and thus raise the output voltage Vo. According to the operation, the Lus Semiconductors 100 a , 100 b are capable of rectification. While the voltage at node 8 of the high frequency transformer 300 is set to be positive, let the reverse biased break down voltage of the diode of the characteristic circuit structure 101 a of the Lus Semiconductor 100 a is higher than the positive voltage at node 8 , thus the voltage at node 8 may not pass through the reversed diode but through the drain and source of the Lus Semiconductor 100 a . While the output voltage Vo is present, even though the voltage at node 8 is at the negative half cycle of the AC voltage, because the reverse biased break down voltage of the reverse coupled Schotty diode in the characteristic circuit structure 101 a is higher than the output voltage Vo, the possibility that the first secondary winding may be burned out by the reverse current of conventional EMFETs can be eliminated. The operation of the characteristic circuit structure 101 b in the Lus Semiconductor 100 b at node 10 is identical. According to the operation of the characteristic circuit structure 101 in the present invention, the reverse biased break down voltage may be configured according to applications and shall not be limited. The operations of voltage regulation in PWM or PFM power systems are known to person skilled in the art and will not be discussed here for conciseness. [0027] FIG. 6 shows one embodiment of half-wave synchronous rectifier and voltage regulation circuit utilizing an EMFET according to the present invention. As shown in the figure, the Lus Semiconductor 100 b , node 10 of the first secondary winding and node 13 of the second secondary winding shown in FIG. 5 were removed and thus became a half-wave synchronous rectifier and voltage regulation circuit. The operation of the circuit is identical to that of the Lus Semiconductor 100 a shown in FIG. 5 and will not be discussed here for conciseness. [0028] FIG. 7 shows one embodiment of full-wave synchronous rectifier and voltage regulation circuit utilizing DMFETs according to the present invention. The difference between the full-wave synchronous rectifier and voltage regulation circuit utilizing EMFETs shown in FIG. 5 and the full-wave synchronous rectifier and voltage regulation circuit utilizing DMFETs shown in FIG. 7 is that DMFETs need a negative voltage supply circuit for the gates to maintain the source and the drain open, such that no source-drain current is developed. The negative voltage supply circuit is constructed with diodes D 6 , D 7 , D 8 , voltage dividing resistors RJ, RG, and a filter capacitor C 4 . The node 14 and node 15 of the third secondary winding are the power source of the negative voltage supply circuit. Diode D 6 functions as a rectifier. Diode D 7 and D 8 prevent the secondary winding from affecting the negative voltage supply circuit of the asynchronous rectification side while the synchronous rectifier is in operation. In short, the operation and structures of the full-wave synchronous rectifier and voltage regulation circuit utilizing EMFETs shown in FIG. 5 and the full-wave synchronous rectifier and voltage regulation circuit utilizing DMFETs shown in FIG. 7 are identical except for the negative voltage required for the gates of DMFETs in FIG. 7 . [0029] FIG. 8 shows one embodiment of half-wave synchronous rectifier and voltage regulation circuit utilizing a DMFET according to the present invention. As shown in the figure, the Lus Semiconductor 100 b , node 10 of the first secondary winding and node 13 of the second secondary winding shown in FIG. 7 were removed and thus became a half-wave synchronous rectifier and voltage regulation circuit. The operation of the circuit is identical to that of the Lus Semiconductor 100 a shown in FIG. 7 and will not be discussed here for conciseness. [0030] It is further stated that EMFETs and DMFETs, like ordinary transistors, are bidirectional, i.e. the drain nodes and the source nodes of the Lus Semiconductors 100 a , 100 b in FIG. 5 , FIG. 6 , FIG. 7 , or FIG. 8 may be reversed while the characteristic of gate-source operating voltage and the characteristic circuits are still maintained. That is, in application, the gate node may be the control node, the source node may be the AC input node and the drain node may be the DC output node, depending on the specifications of the manufacturer, the drain node and the source node may be alternated and is not limited by the embodiments above.

The Lus, Semiconductor in this invention is characterized by replacing the static shielding diode (SSD) of traditional Enhancement Mode Field Effect Transistors (EMFETs) or Depletion Mode Field Effect Transistor (DMFETs) with polarity reversed (comparing with traditional SSD) SSD, Schottky Diode, or Zener Diode, or face-to-face or back-to-back coupled Schottky Diodes, Zener Diodes, Fast Diodes, or Four Layer Devices such as DIAC and TRIAC. With the proposed Power EMFETs or DMFETs of which the drain to source resistors (Rds) are quite low, high efficiency synchronous rectification may be achieved.

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. provisional patent application 60/754,655 filed 30 Dec. 2005 is the national phase under 35 U.S.C. §371 of PCT/SE2006/001489 filed 22 Dec. 2005. FIELD OF INVENTION The present invention relates generally to high voltage bushings and more particularly to a high voltage bushing partially submerged in an insulating liquid, such as oil. The invention also relates to a high voltage device comprising such bushing. BACKGROUND It is known that electrical equipment and devices, such as high voltage transformers, are usually equipped with bushings, which are suitable to carry current at high potential through a grounded barrier, e.g. a transformer tank or a wall. Conventional high voltage transformer bushings are constituted by an insulator made of ceramic or composite material, which is provided with sheds and is generally hollow, and on the inside is the voltage grading performed with a condenser body comprising paper-oil or resin impregnated epoxy through which the electrical conductor passes, allowing to connect the inside of the device on which the bushing is fitted to the outside. Thus, the condenser core provides a smooth electric potential distribution between the high voltage and the grounded parts. Common to transformer bushings with a condenser body is that the part of the bushing that is submerged in the transformer tank contains oil. SUMMARY OF THE INVENTION An object of the present invention is to provide a high voltage bushing which has good dielectric and thermal properties, which contains few parts and is easily adapted to different applications. The invention is based on the realization that a bushing with a grounded shielding tube instead of a condenser core can be used in applications wherein part of the bushing is submerged in oil. This is the case in for example transformer bushings, which are submerged in transformer oil in a transformer tank. According to a first aspect of the invention a high voltage bushing for a high voltage device containing insulating liquid is provided comprising a hollow insulator housing comprising a first side insulator arranged to be provided outside of the high voltage device and a second side insulator arranged to be submerged in the insulating liquid of the high voltage device, and a high voltage conductor provided in the hollow insulator housing; and being characterized by a voltage grading shield provided between the high voltage conductor and the insulator housing. According to a second aspect of the invention a high voltage device comprising at least one such bushing is also provided. With the inventive bushing, several advantages are obtained. By using a shielding tube, the bushing can be made completely dry, i.e., it contains no oil. Also, it has been shown that the electric field pattern in the bushing is almost identical for both AC and DC applications, making the bushing suitable for both AC and DC. In a preferred embodiment, an insulating gas, such as SF6 or N 2 or mixtures thereof, is used as insulating medium inside the part of the bushing that is connected to the high voltage device. This provides good thermal properties due to the insulating gas and the open design allowing the gas to circulate inside the bushing. BRIEF DESCRIPTION OF DRAWINGS The invention is now described, by way of example, with reference to the accompanying drawing, in which the sole FIG. 1 is a sectional view of a high voltage bushing mounted to a high voltage device. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In the following a detailed description of a preferred embodiment of the present invention will be given. In this description, the term “high voltage” will be used for voltages of 50 kV and higher. Today, the upper limit in commercial high voltage devices is 800 kV but even higher voltages, such as 1000 kV or more, are built or envisaged in the near future. Also, in this description the term “voltage grading shield” should be read to exclude condenser cores conventionally found in bushings arranged to be submerged in insulating liquid. Reference is now being made to the FIGURE. The bushing, generally designated 1 , comprises a high voltage conductor 2 that extends through the center of a hollow gas filled bushing insulator 4 a , 4 b that forms a housing around the high voltage conductor. The bushing has two sides, a first side or air side outside the high voltage device to which the bushing is mounted, and a second side or transformer side submerged in an insulating liquid in the high voltage device to which the bushing is fitted, in the present example a transformer, generally designated 20 . The transformer contains insulating liquid 22 , such as transformer oil, which is enclosed by a tank, designated 24 . The air side of the transformer bushing is similar to a conventional gas insulated gas-to-air bushing, mainly consisting of the high voltage conductor 2 and an air side insulator 4 a separating the gas inside the bushing from the surrounding air. Further, the transformer side of the bushing is separated from the oil 22 in the transformer by a transformer side insulator 4 b. The insulator, which is preferably made of a composite material, such as epoxy, but could also be made of porcelain, thus comprises two portions: an air side insulator 4 a on the air side of the bushing and a transformer side insulator 4 b on the transformer side of the bushing. A flange 6 is provided to electrically connect the housing of the bushing to ground 28 through the tank 24 of the transformer 20 . A so-called throat shield or voltage grading shield in the form of a concentric grounded tube 8 is provided inside the hollow bushing insulator 4 a , 4 b around the portion of the bushing going into the tank 24 . This shield 8 , which is made of a suitable conductive material, such as aluminum, accomplishes grading of the electrical field in the bushing and is used instead of a condenser core. The voltage grading shield 8 is surrounded by the insulating gas, such as SF6 or N 2 or mixtures thereof, which is provided in the space 10 a inside of the air side insulator 4 a and the space 10 b inside of the transformer side insulator 4 b . It is preferred that these two spaces 10 a , 10 b are in communication with each other to provide circulation of the insulating gas, thereby improving cooling of the transformer side of the bushing 1 . In DC applications, the inside of the transformer side insulator 4 b , i.e., the surface of the transformer side insulator facing the insulation gas inside the insulator, may be covered with a dielectric material (not shown) with a relatively low resistivity, such as silicone rubber, composite material or varnish. Since the resistivity of silicone rubber is almost of the same order of magnitude as that of the oil inside the transformer, improved electric field distribution is obtained. This layer minimizes internal radial field stresses in the transformer side insulator 4 b separating the gas in the bushing 1 from the oil 22 in the transformer 20 and provides a smooth grading of the potential along the transformer side insulator 4 b between the high voltage and the grounded flange 6 and increases thereby the dielectric strength of the insulator 4 b. Optimal performance is obtained by a geometrical design of the transformer side insulator 4 b . In the preferred embodiment, the transformer side insulator has an essentially frusto-conical shape. This could be supplemented by the thickness of the coating on the inside of the bushing or the thickness of the insulator 4 b housing. In order to further improve the performance, the thickness of the coating can vary along the transformer side of bushing. A shielding ring 12 provided at the end of the transformer side of the bushing and a corresponding barrier system 26 in the transformer connection can further enhance the performance. In both AC and DC applications, in order to achieve a smooth grading of the potential along the transformer side insulator 4 b between the high voltage and the grounded flange, the geometry of the transformer side insulator 4 b is optimized. Also, in DC applications the geometry of the barrier system 26 in the transformer is taken into account when optimizing the bushing. A preferred embodiment of a high voltage bushing and a high voltage device according to the invention has been described. A person skilled in the art realizes that these could be varied within the scope of the appended claims. Thus, although the high voltage device to which the inventive high voltage bushing is attached has been described as a transformer, it will be appreciated that this could be other devices containing insulating liquid, such as reactors or breakers. The inventive bushing has been described as an air-oil bushing, i.e., wherein the first side of the bushing is surrounded by air outside a transformer, for example. It is realized that this first side can be provided in other environments, such as in oil in an oil-oil bushing or in gas in a gas-oil bushing. The transformer 20 has been described with a barrier 26 . It is realized that this barrier is optional. The bushing has been shown with a second side insulator, which has essentially frusto-conical shape. It will be realized that the shapes of the insulators can deviate from this shape without departing from the inventive concept. Thus, an inventive bushing with an insulator that is at least partly cylindrical will be a possibility.

A high voltage bushing for a high voltage device containing insulating liquid includes a voltage grading shield, improving performance and facilitating manufacturing.

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an escalator. Definitions The term escalator should comprise both escalators with steps, as they are used in department stores, for example, and moving sidewalks with pallets, as they are used in airports, for example. FIG. 1 schematically shows a pintle chain G and a chain wheel R partially wrapped round the latter, to initially define a few terms. The pintle chain G comprises chain links K linked to each other via a pivot point P. The chain wheel K shown in an exemplary manner, has eight teeth Z, between which tooth spaces are arranged, into which pivot points P can engage. The angular pitch τ between two teeth or two tooth spaces is 45° in the example shown. Furthermore, an entry angle φ is shown at the bottom side of the chain wheel in FIG. 1 , which can arise, for example, due to a guide for deflecting pintle chain G. The entry angle φ is measured between the actual exit direction of the pintle chain G and the normal S on the line connecting detachment point A of the pintle chain G from the chain wheel R and the axis of rotation D of the chain wheel R. The entry angle φ is about 11° in the example shown. A momentary angle of wrap υ is indicated in FIG. 1 , which corresponds to the circumferential angle between two detachment points A of the pintle chain G from the chain wheel R, and is 180° in the case shown. When a chain link K detaches from the chain wheel R, the momentary angle of wrap D will be abruptly reduced, because with different entry angles φ at the top and bottom, a chain link K detaches at the top, for example, while at the same time the next chain link K has not contacted the bottom yet, however. This is why an average angle of wrap υ will be assumed in the following, which is equal to or greater than the minimum angle of wrap and equal to or smaller than the maximum angle of wrap. Furthermore, at the top of the chain wheel R, an effective lever arm H eff is indicated, which corresponds to the vertical distance between the effective line W of force, in particular tensile force of the pintle chain G and the rotary axis D of the chain wheel R. Like the momentary angle of wrap υ, the effective lever arm H eff also varies during the movement of the pintle chain due to the detachment of the pintle chain one link at a time, in particular due to the polygonal contact of the chain on the chain wheel. At the bottom side of the chain wheel R, the effective lever arm H eff ′ is a bit shorter, while due to the slightly inclined effective line W of force of the pintle chain G, the effective lever arm H eff ′ does no longer extend through the detachment point A. State of the Art In escalators or moving sidewalks, their steps or pallets, are usually driven by drive chains, in particular on both sides, formed as so-called step chains or pallet chains, and are also attached to the latter. Usually the drive chains have 3 or 4 subdivisions, i.e. 3 or 4 links per step. The chain wheels used have about 16 to 25 teeth. This relatively high number is chosen to minimize the so-called polygonal effect. The polygonal effect comes about by the variations in the effective lever arm H eff (see FIG. 1 ). Chain wheels are usually driven with constant angular velocity. Due to the variations in the effective lever arms, the velocity of the step chains also varies, the incessant acceleration and deceleration of the moved masses (chains, axles, steps) results in the generation of mass forces, which are transmitted as disturbing forces or torques into the step or pallet chains or into their drives, and lead to a shortened service life, or are a quantity which must be taken into account when designing the drive components, in particular. Moreover, the moving parts in an escalator combined with the surrounding steel structure, form a spring-mass system capable of vibration. In particular, the chains can be seen as springs, and steps, axles (if any), wheels, the people transported (on the steps or pallets) and again the chains, are to be seen as masses. This spring-mass system can have very unfavorable operating points depending on the parameters, as a function of the number of teeth of the chain wheels, the traversing velocity and the load. In practice, this problem is usually solved by reducing the chain pitch and increasing the number of teeth. As the pitch is reduced and the number of teeth is increased, the polygonal effect is reduced, until a degree is reached, where the polygonal effect is so low in practice, i.e. the movement of the chains/steps/pallets is so uniform, that the polygonal effect causes practically no problem, but is still present. Also, guides have been installed in the area of the chain wheels, which effect tangential entry of the chain onto the chain wheels. The primary aim of this measure is to reduce the entry noise of the chain on the chain wheels. Also, the polygonal effect is reduced hereby, but not compensated. The conventional structure with relatively small chain pitch and a relatively high number of teeth of the chain wheels has substantial drawbacks, however. First of all, the high cost of the chain for the steps or pallets is to be mentioned. The more subdivisions (the smaller the pitch) for the latter, the more links per step or per meter, and the higher its cost. Moreover, there is a higher number of positions per step/pallet, subject to wear. Over the period of operation of the escalator, adherence to the maximum admissible spacing between steps/pallets for as long as possible, is a very important criterion. Due to the high number of teeth, the chain wheels have a relatively great diameter and need a large structural space, in particular for the drive station. This is how valuable space is lost in buildings. Due to great diameters, high driving moments are necessary, which entails higher cost for the drives. An escalator of the initially mentioned type is known from European Patent Application EP 1 344 740 A1. The escalator described there has a chain wheel driven in a manner polygonally compensated by the upper strand, wherein a pintle chain partially wraps around the chain wheel. The chain wheel has an odd number of teeth. Due to the odd number of teeth, the lower strand does not run in a polygonally-compensated manner, but rather irregularly. Since the lower strand has also masses applied to it, such as the masses of chains, wheels, axles and steps or pallets, forces result from this irregularity, which are transmitted to the steps or pallets in the upper strand. Such an escalator may run comparatively smoothly in a heavily loaded state, due to the large quotient between the mass in the upper strand and the mass in the lower strand. In the unloaded state, or loaded with only few people, however, the upper strand will also run in a very uneven manner. The problem on which the present invention is based, is the creation of an apparatus of the initially mentioned type, which runs comparatively smoothly even with a relatively low number of teeth on the at least one chain wheel. BRIEF SUMMARY OF THE INVENTION Summary of the Invention The objects of the invention are achieved by the escalator described herein. The effective lever arm of the chain at the at least one chain wheel in the upper strand is essentially equal to the effective lever arm of the chain at the at least one chain wheel in the lower strand. In the polygonal compensation configured for the upper strand, for example, this results not only in a constant velocity of the running of the upper strand, but also of the lower strand. The solution according to the present invention allows step or pallet chains with substantially increased pitch, such as chain pitch equal to half of the step pitch or a chain pitch equal to the step pitch, to be used and/or to reduce the structural space required. In one example the first chain wheel and the second chain wheel are operated in a manner offset with respect to each other in such a way that, with a minimal effective lever arm at the first chain wheel in the same strand, the effective lever arm on the second chain wheel is not minimal, preferably deviates by ±20% or less of the difference between the maximum and minimum values from the maximum value, and is maximal, in particular. For this purpose, for example, the angular position of the first chain wheel can differ from that of the second chain wheel by at least ±30%, preferably by at least ±40% of the angular pitch, in particular by half of the angular pitch. This opposition in phase of the two chain wheels results in a reciprocating movement of the second chain wheel, configured as an idler wheel, for example, being reduced. In one example the escalator has at least one guide, which can influence the entry angle of the chain on the first and/or the second chain wheel, wherein the at least one guide is arranged in such a way that the entry angle with the minimum effective lever arm is smaller than with the maximum effective lever arm. Such an arrangement of the guide has the result that the oscillating movement of the redirecting station approaches zero when the machine is running, which has a positive effect on running smoothness. Moreover, this arrangement of the at least one guide has the effect that the wheels are only minimally loaded. This means that it is possible to use relatively cheap wheels. Further features and advantages of the present invention will become clear in the following description of preferred exemplary embodiments with reference to the accompanying drawings, wherein: BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG. 1 is a diagram of a chain wheel and a pintle chain to illustrate the terms used; FIG. 2 is a diagrammatic side view of an escalator according to the present invention with an idler chain wheel; FIG. 3 is a diagrammatic side view of an escalator according to the present invention with a redirecting arc instead of an idler chain wheel; and FIG. 4 is a diagrammatic enlarged view of several components essential for the function of the escalator according to FIG. 2 . DESCRIPTION OF THE INVENTION The escalator as shown in FIG. 2 comprises a chain 1 configured as a pintle chain, wrapped around a first, driven chain wheel 2 and a second chain wheel 3 acting as an idler wheel. Each of the chain wheels 2 , 3 has six teeth, only diagrammatically indicated. The steps or pallets (not shown) of the escalator are attached to the chain 1 . A circulating hand rail 4 is only schematically shown in FIGS. 2 and 3 , which can be held by a user during the movement of the escalator. Between the chain wheels 2 , 3 , the chain 1 forms an upper strand 5 , shown at the top in each of FIGS. 2 to 4 , and a lower strand 6 , shown at the bottom in each of FIGS. 2 to 4 . The first chain wheel 2 is driven in a manner free of the polygonal effect, or polygonally compensated, by a drive motor 7 via a drive chain 8 . This can be achieved, for example, in the exemplary embodiment shown, by a non-circular wheel 9 engaging the drive chain 8 . Further possibilities of a polygonally-compensated drive are known from the WO 03/036129 A1, which is explicitly incorporated herein by reference. The polygonally-compensated drive allows the first chain wheel 2 to be driven with a non-constant angular velocity in such a way that the driven chain 1 is running at a constant, or near-constant, velocity. I.1. The link chain drive which forms the basis of a first aspect of the invention comprises a drive chain sprocket for a link chain and comprises a drive system which can drive the drive chain sprocket with a non-uniform rotational speed for the purpose of compensating speed fluctuations of the link chain. Here and below, a “drive system” should be understood in a broad sense to mean any system which can output forces or torques to the drive chain sprocket. This encompasses in particular drive systems in the narrower sense, in which said forces or torques are actively generated, for example by means of an electric motor. Also encompassed, however, are “passive” drive systems in which said forces or torques are extracted from inertial systems such as for example a rotating flywheel mass. In a first embodiment, the link chain drive is characterized in that the drive system comprises the following elements: two wheels which are coupled by means of an endlessly encircling flexible traction mechanism, such that the rotation of one wheel can be transmitted to the other wheel via the traction mechanism; a movable tensioning element such as for example a tensioning roller which, by acting on the load-bearing strand of the traction mechanism, changes the effective length of the load-bearing strand; the load- bearing strand of the traction mechanism is by definition that portion of the flexible traction mechanism via which the force is transmitted from the driving wheel to the driven wheel. The stated change in length is preferably periodic and synchronous with the rotation of the drive chain sprocket from tooth to tooth. I.2. The invention furthermore relates to a second embodiment of a link chain drive comprising a drive chain sprocket for a link chain and comprising a drive system (in the broad sense explained above) which can drive the drive chain sprocket with a non-uniform rotational speed for the purpose of compensating speed fluctuations of the link chain. Here, the drive system comprises two wheels which are coupled by means of an endlessly encircling flexible traction mechanism. According to a first variant, the link chain drive is characterized in that the axle of one of the two wheels is mounted eccentrically. According to a second variant, the link chain drive is characterized in that the axle of one of the two wheels is mounted so as to be movable and is connected to a diverting mechanism. The eccentric mounting of the wheel causes a periodic change in length of the load-bearing strand, and as a result a non-uniform rotational speed of the drive chain sprocket, which reduces the polygon effect if the relationships are configured such that a rotation of the eccentric wheel rotates the drive chain sprocket precisely one tooth further. I.3. According to a third embodiment of the underlying link chain drive having a drive chain sprocket for a link chain and having a drive system of non-uniform rotational speed, the drive system comprises the following elements: a motor, in particular an electric motor (geared motor), the rotor (component which is set in rotation) of which is coupled to the drive chain sprocket and the stator (component which does not rotate) of which is movable; a mechanism for moving the stator synchronously with the rotation of the drive chain sprocket. Here, the stated mechanism preferably comprises a cam element which is coupled to and interacts with the drive chain sprocket and which is followed by a follower element, wherein the relative movement generated between the cam element and the follower element is transmitted to the stator of the motor. II.1. According to a second aspect, the invention relates to a link chain drive which may be in particular an intermediate drive for an extended link chain, comprising a drive wheel with a shaft and with radially projecting teeth which engage in a force-transmitting manner into the link chain, and comprising a drive system which is coupled to the shaft in order to be able to actively set the drive wheel in rotation. The link chain drive is characterized in that the shaft— and therefore also the drive wheel— is mounted such that it can be displaced spatially in parallel. Here, the translation of the shaft preferably takes place only radially (without an axial component) with respect to its original position. III.1. According to a third aspect, the invention relates to a link chain guide comprising a diverting wheel around which a link chain is guided. In the present case, “diverting wheel” is intended to denote both an actively driven wheel (“drive wheel”) and also a non-driven wheel. Furthermore, the link chain guide comprises a support element which makes contact with the chain links of the link chain directly before they arrive at the diverting wheel. The link chain guide is characterized in that the support element is movably mounted in such a way that it can be moved synchronously with the rotation of the diverting wheel, in order to reduce the speed difference between the chain links and the diverting wheel at the time at which the chain links arrive at the diverting wheel. III.2 According to the third aspect, the invention furthermore relates to a link chain guide having a diverting wheel around which a link chain is guided, and having a support element which makes contact with the chain links before they arrive at the diverting wheel, wherein the link chain has a bent profile between its primary running direction and the diverting wheel. The link chain guide is characterized in that the support element is arranged in the region of the bent profile of the link chain and is designed such that the movement of the chain links is adapted, before they arrive at the diverting wheel, to the movement of the associated tooth spaces. IV.1. According to a fourth aspect, the invention relates to a link chain guide having a diverting wheel around which a link chain is guided. The link chain guide is characterized in that the diverting wheel is coupled to inertia compensation means, by which forces synchronous with the rotational movement of the diverting wheel are exerted on the diverting wheel such that speed fluctuations of the link chain owing to inertial influences of the diverting wheel are reduced. The hand rail 4 is driven by the drive motor 7 , wherein the hand rail 4 is driven at a constant angular velocity. The second chain wheel 3 is supported by means of a moveable support 10 in a displaceable manner. In the view according to FIG. 4 , the chain 1 is shown shortened. FIG. 4 shows that the second chain wheel 3 is offset from the first chain wheel 2 with respect to its angular position. For example, a radial line 12 extending through one of the contact points 11 of the chain 1 forms an angle α with the horizontal 13 on the first chain wheel 2 in FIG. 4 , which is about 60°. In contrast, a radial line 15 extending through the corresponding contact point 14 of the chain 1 forms an angle β with the horizontal 13 on the second chain wheel 3 in FIG. 4 , which is about 30°. The angular positions of the chain wheels 2 , 3 therefore differ by 30°, which corresponds to half the angular pitch of the chain wheels 2 , 3 each having six teeth, because the angular pitch is 360° divided by the number of teeth. This difference in the angular positions of chain wheels 2 , 3 has the result that precisely at the point, where the chain 1 applies a minimum effective lever arm 16 , 16 ′ on the first chain wheel 2 , the chain 1 applies a maximum effective lever arm 17 , 17 ′ on the second chain wheel 3 (see FIG. 4 ). In the reverse case, the chain 1 applies a maximum effective lever arm to the first chain wheel 2 whenever the chain 1 applies a minimum effective lever arm on the second chain wheel 3 (not shown). Further, it can be seen from FIG. 4 that the effective lever arm 16 in the upper strand 5 on the first chain wheel 2 is equal to the effective lever arm 16 ′ in the lower strand 6 . Further, it can be seen from FIG. 4 that the effective lever arm 17 in the upper strand 5 is also equal to the effective lever arm 17 ′ in the lower strand 6 on the second chain wheel 3 . Guides 18 , 19 as seen from FIG. 4 can define the entry angles φ 1 , φ 2 of the chain 1 on the chain wheels. Herein, in particular, the guide 18 is arranged toward the bottom in FIG. 4 to such an extent, or the guide 19 is arranged toward the top in FIG. 4 to such an extent that the entry angle φ 1 with minimum effective lever arm 16 , 16 ′ (c.f. first chain wheel 2 in FIG. 4 ) is substantially smaller than the entry angle φ 2 with maximum effective lever arm 17 , 17 ′ (c.f. second chain wheel 3 in FIG. 4 ). In the embodiment according to FIG. 3 , a redirecting arc 20 is provided instead of the second chain wheel 3 . The radius for this redirecting arc 20 is chosen such that the effective lever arm (not shown) in the upper strand 5 is equal to the effective lever arm in the lower strand 6 also on the redirecting arc 20 . Furthermore, in the embodiment according to FIG. 3 , the guides 18 , 19 are also able to guide the chain 1 into the redirecting arc in such a way that the entry angle with minimum effective lever arm is substantially smaller than the entry angle with maximum effective lever arm. Furthermore, the redirecting arc 20 , the first chain wheel 2 and the chain 1 can be configured and arranged in such a way that whenever the chain 1 applies a minimum effective lever arm 16 , 16 ′ to the first chain wheel 2 , the chain 1 applies a maximum effective lever arm to the redirecting arc 20 , and vice-versa. A further partially functional description of the exemplary embodiments can be derived from the following. The chain wheels 2 , 3 used have an even number of teeth. This applies in the case that the angle of wrap of the chain 1 is about 180°, which is the normal case for escalators/moving sidewalks. What is crucial is that the effective lever arm on the side of the upper strand is always essentially identical to the effective lever arm on the side of the lower strand. This has the effect, in a polygonal compensation configured for the upper strand, that not only the upper strand runs at a constant velocity, but also the lower strand (in the case of an odd number of teeth and with a angle of wrap of 180° the lower strand would run with about double the irregularity as a conventional, i.e. not polygonally-compensated drive). The angle of wrap can also deviate from 180° under the condition that the effective lever arms are identical for the upper and lower strands. This means that the number of teeth and the angle of wrap must be adapted for this case. When this condition is fulfilled, uniform chain velocities will result in the upper and the lower strand, which are requisite for smooth running of the escalator/the moving sidewalk. The same rule also applies to the non-driven redirecting or idler station (with escalators it is usually the lower landing station) as to the driven chain wheel 2 . Again, it is crucial to provide for identical effective lever arms. This also applies in the case where a chain wheel 3 is not used for redirecting, but a non-toothed, stationary-mounted or spring-loaded/elastically-mounted redirecting arc 20 is used. This means that the radii or diameters of the redirecting arc must be configured in such a way while also taking the diameter of the chain wheels into account, that the link center points of the chain 1 run on a corresponding pitch circle corresponding to that of a chain wheel having the corresponding number of teeth. Since the chain wheels 2 , 3 do not run at a constant angular velocity and this effect becomes greater the smaller the number of teeth, care must be taken that they are configured to be as light as possible, i.e. having only a small moment of inertia, so that the disturbing forces exerted by them on the chains/steps/pallets, are as small as possible. In particular, weight optimization must be observed for the points further removed from the pivot point, and weight reduction recesses or the like must be provided, if necessary. Due to the polygonal contact of chain 1 , in particular with large links, on the chain wheels 2 , 3 , usually the axle distance between the chain wheels 2 , 3 changes from tooth engagement to tooth engagement. The chain 1 always has a constant length, apart from elastic expansion. The drive chain wheels are usually mounted in a stationary manner, and the idler chain wheels are resilient and linearly moveable on the fixture 10 . The idler chain wheels therefore make a linear movement from pitch to pitch. This is the larger the greater the chain pitch and the smaller the number of teeth on the chain wheel. In conventional escalators having a relatively small chain pitch and a relatively large number of teeth, as the case may be, this problem does not need to be addressed. Since the pitch may be very large in an escalator (or moving sidewalk) according to the present invention, namely 1/1 or 1/2 of the step/pallet pitch, and the number of teeth may be very small, namely up to 6 or 4, the linear movement of the second chain wheel 3 acting as the idler wheel or the redirecting arc 20 can be so large that it will develop into a component disruptive for the smooth running of the escalator/the moving sidewalk. Disturbing mass forces result from this large linear movement of the redirecting station, and disturbing noises may also arise. The constellation is particularly disadvantageous if the drive and idler chain wheels have the same angular position (measured, for example, by angle α or β of a chain wheel corner relative to the horizontal). This is why the relative angular position α, β of the chain wheels 2 , 3 must be observed, i.e., it should be opposed in phase: about half of a pitch angle (±20%) must be between the angular position of the first chain wheel 2 and that of the second chain wheel 3 (pitch angle=360° divided by the number of teeth). This means that the axle distance, the lifting height and the length of the chains must be adapted to each other. Further, the first and second chain wheels 2 , 3 should have the same number of teeth, if possible. Deviations from the same number of teeth within a range of ±30% are tolerable. Furthermore, guiding of the chains is important. The guides 18 , 19 used in an exemplary embodiment of the escalator according to the present invention have the effect that the chain 1 runs onto the chain wheels 2 , 3 a little above the minimum effective lever arm. Furthermore, they are optionally curved at their ends, which has the effect that a velocity component in a radial direction is applied to the chain 1 shortly before contacting the chain wheels 2 , 3 , or after running off the chain wheels 2 , 3 . The impact component of the chain link points into the tooth spaces of the chain wheels, or onto the guides 18 , 19 is therefore substantially reduced, which leads to considerably lower noise and more advantageous running properties. Chain guides which cause the chains to run tangentially onto the chain wheels and therefore reduce entry noise (chain on chain wheel) cannot be used in an escalator according to the present invention, because due to the low number of teeth of the chain wheels and the resulting ratios of angles the stresses for the wheels become too great, or the wheels would have to be dimensioned for these stresses, which would make them very expensive. Moreover, a large oscillating movement of the redirecting station would result from this arrangement of the guides, which would lead to the above mentioned drawbacks. In an escalator according to the present invention, the correct height of the guides 18 , 19 between the minimum and maximum effective lever arm is near the minimum lever arm. If they are set at the correct height, the result is that the oscillating movement of the redirecting station approaches zero when the machine is running, which greatly improves smooth running. Moreover, the wheels are only slightly stressed with this arrangement of the guides. This means that relatively cheap wheels can be used. The optimum height of the chain guides is determined as follows: The chain links are pivoted about a predetermined angle, when they leave the guides 18 , 19 . It is possible to draw or conceive small rectangular triangles there, the hypotenuse of which is the chain link in question, wherein one of the small sides is formed by the horizontal. All quantities may also be calculated with the aid of the angular functions. The sum of the horizontal small sides is now formed and various angular positions of the chain wheels are determined within a pitch angle. It is now imagined that the chains continue running another little bit and the chain wheels rotate further until they have rotated about a pitch angle. A pitch angle of about 60°, for example, is thus subdivided into 20 steps of 3° each, for example. The height of the guides is now changed until the sum of the horizontal small sides results in a value which is as constant as possible over the various angular positions. Where these deviations have reached their minimum, the linear movement of the idler chain wheels/the redirecting station is also at its minimum. In real escalators, polygonal effects would also have to be taken into account, if any, which result in the transitions from horizontal to inclined portions (redirecting radii) when the chains run through the chain guides.

An escalator includes a plurality of steps or panels, a chain for driving the steps or panels, at least one chain wheel around which the chain is deflected and wherein the chain, starting from the chain wheel, forms an upper strand and a lower strand. There is also provided a device for the polygonal compensation of the movement of the at least one chain wheel. The effective lever arm of the chain on the at least one chain wheel in the upper strand is substantially equal to the effective lever arm of the chain on the at least one chain wheel in the lower strand.

RELATED APPLICATIONS This application derives priority from U.S. provisional patent application Ser. No. 61/092,522 filed Aug. 28, 2008 FIELD This invention relates to communications over power lines of a utility's electrical distribution system or network using a two-way automated communications system or TWACS®; and more particularly, to a method for low-frequency data transmissions over the power lines. In TWACS, messages sent from a source within the system (a central station, substation, or the like) to customer sites are referred to as outbound messages. These messages typically are used to check on the status of the power usage at a site (polling), convey instructions related to power usage at the site, etc. Reply messages sent from the site back to the transmission source are referred to as inbound messages. These messages are transmitted by a transponder located at the site and provide information or data about power usage at the site for use by the utility in its operations. The outbound transmission scheme employed by TWACS has been found to work reliably using only one pulse per bit. This is possible because the utility can scale up signal transmission power by using a very large signaling load. However, the strength of an inbound transmission is limited by a number of factors. These include not only the need to avoid saturating small service transformers, but also constraints on the size, cost, and power consumption of the transmitting circuit. A result of this is that it is not always possible for the transponder to transmit a signal with adequate signal power to the substation, particularly if the transponder generates only one current pulse per bit. The signaling scheme that has evolved for inbound messages because of these constraints currently uses four pulses per bit. At present, there is a need to reduce the amount of power required for inbound message transmissions. Doing so will alleviate a number of problems that now exist when a transponder is subjected to high source impedances, such as light flicker, harmonic distortions, and AM radio interference. In addition, reducing the instantaneous amount of current drawn by a transponder will make the TWACS more viable in situations where it is installed below a circuit breaker at the customer's site. One way of reducing instantaneous transmission power, without sacrificing the signal-to-noise ratio at the substation, is to use longer pulse patterns for each bit in the inbound message. Each doubling of the length of a bit allows a reduction in the signaling current by a factor of √2. Thus, increasing the length of the bit from, for example, the current 8 half-cycles to 16 half-cycles, makes it possible to reduce the present current requirement of 17 amps RMS to 12 amps RMS, while maintaining the same level of performance. SUMMARY OF THE INVENTION The present invention is directed to a method for use in a two-way automatic communication system (TWACS) of producing a set of inbound message pulse patterns and orthogonal detection vectors for lengths longer than 4 cycles of an AC waveform. Hadamard matrices are used for this purpose and are adapted to generate a set of detection vectors by permuting rows of a matrix and removing certain columns of the matrix to meet system design requirements. The method can be extended to any length and modified to accommodate multiple pulses per half-cycle to support higher data rates. Using the method, sets of pulse patterns of an arbitrary length are produced and then used to produce longer pulse patterns usable in a TWACS for generating bits of an inbound message. Use of the method significantly reduces the power requirements for the transmission of bits comprising an inbound TWACS message. Tables for generating “0” and “1” pulse patterns and detection vectors for channel sets of 8, 16, and 32 are presented. Other objects and features will be in part apparent and part pointed out hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS The objects of the invention are achieved as set forth in the illustrative embodiments shown in the drawings which form a part of the specification. FIG. 1 illustrates a transmitted pattern of four current pulses, and the corresponding signal received at a substation after passing through a transformer of the power distribution system; FIG. 2 illustrates the frequency response of channel detection vectors for a channel set 8 A in the current TWACS protocol; FIG. 3 presents a comparison of a sequency-ordered Hadamard matrix of size 64 (left side of the Fig.) and a Discrete Cosine Transform matrix of size 64 (right side of the Fig.); FIG. 4 presents a comparison of the frequency content of 14 channels in a channel group 16, where the channels are ordered in sequency order; and, FIG. 5 represents the frequency response of hypothetical channel detection vectors for 8 half-cycles with 2 current pulses per cycle. Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION It will be understood by those skilled in the art that pulse patterns used to produce bits transmitted over a power line must satisfy certain system constraints. In TWACS, for example, for a pulse pattern with a length of N half-cycles, a transponder (not shown) transmits pulses in one-half of the half-cycles of a 60 Hz AC waveform in order to signal a logical “0”; and in the opposite combination of half-cycles to signal a logical “1”. Accordingly, N is an even number. Referring to FIG. 1 , a modulated waveform W is illustrated. The waveform is produced by switching a signaling load (not shown) into a circuit near the zero crossing of the AC waveform in four of eight sequential half cycles of the waveform. The polarity of each of the pulses is determined by the polarity of the AC waveform at the particular zero crossing. The pulse pattern shown here corresponds to a logical “0” in channel 4 of a set of six channels. Two additional waveforms, indicated RS and IS respectively, are also shown in FIG. 1 . The signal waveform RS corresponds to the transmitted pulse pattern, and represents the logical “0” in channel 4 of the channel set. The signal waveform IS represents a logical “0” transmitted by a different transponder in a different channel; e.g., channel 3, at the same time as waveform W. Table 1 below shows the complete set of pulse patterns for the channel set. In Table 1, a 0 represents the absence of a pulse, and a 1 or −1 respectively represents the presence of a pulse in either the positive or negative direction at a zero-crossing. It will be noted by those skilled in the art that, in addition to using exactly half of the available half-cycles to transmit pulses, each pattern contains an equal number of pulses in the positive direction and in the negative direction. This prevents any given pulse pattern from containing a net direct current (DC) component since this can cause problems in distribution transformers and because energy close to DC does not propagate well through transformers and is wasted energy. This requirement therefore implies that there must be an even number of pulses in any pattern; which, combined with the requirement that the “1” and “0” sequences have the same number of pulses, further implies that N, the total length in half-cycles, must be a multiple of 4. TABLE 1 Pulse patterns for a logical 1 and 0 in six TWACS inbound channels of a channel set “A”. Each column represents one half-cycle of an AC waveform. Channel # “1” Pattern “0” Pattern 1 1 −1 1 −1 0 0 0 0 0 0 0 0 1 −1 1 −1 2 1 −1 0 0 1 −1 0 0 0 0 1 −1 0 0 1 −1 3 1 −1 0 0 0 0 1 −1 0 0 1 −1 1 −1 0 0 4 1 0 1 0 0 −1 0 −1 0 −1 0 −1 1 0 1 0 5 1 0 0 −1 1 0 0 −1 0 −1 1 0 0 −1 1 0 6 1 0 0 −1 0 −1 1 0 0 −1 1 0 1 0 0 −1 TABLE 2 Decode vectors for each of the six TWACS inbound channels. Each column represents one half-cycle of the AC waveform. Channel # Decode Vector 1 1 −1 1 −1 −1 1 −1 1 2 1 −1 −1 1 1 −1 −1 1 3 1 −1 −1 1 −1 1 1 −1 4 1 1 1 1 −1 −1 −1 −1 5 1 1 −1 −1 1 1 −1 −1 6 1 1 −1 −1 −1 −1 1 1 Table 2 above shows the detection vectors for the channel set associated with the pulse patterns listed in Table 1. The signals are detected by adding and subtracting the contents of each half cycle according to the appropriate detection vector listed in Table 2. So, if a “1” is transmitted in channel 4, the output of the detection is the inner product of: [1 0 1 0 0 −1 0 −1][1 1 1 1 −1 −1 −1 −1] T =4 The inner product of the “0” sequence with the detection vector is −4, and the inner product with any “1” or “0” sequence from any of the other channels is 0. By using this detection scheme, the interfering signal IS from a different channel, as shown in FIG. 1 , is removed. To characterize the detection process mathematically for a generalized set of channel patterns, let a vector p 0 represent a pulse pattern for a “0” in some arbitrary channel, let a vector p 1 represent the corresponding pulse pattern for a “1” in that channel, and let a vector d represent the corresponding detection vector. The goal in the design of detection vector d is that it contains the values 1 and −1 arranged in a pattern such that the inner product of p 1 and d is N/2, and the inner product of p 0 and d is −N/2. It can be shown that this is achieved when d=p 1 −p 0 .  (1) The pulse patterns p 0 and p 1 are derived from detection vector d by observing that regardless of their contents, if p 1 and p 1 follow the two design constraints outlined previously, then p 1 +p 0 =[1 −1 1 −1 . . . ]≡ q.   (2) By adding or subtracting a vector q on both sides of equation (1), we obtain the following: p 0 = 1 2 ⁢ ( q + d ) ⁢ ⁢ and ( 3 ) p 1 = 1 2 ⁢ ( q - d ) ( 4 ) Therefore, since it is possible to derive pulse patterns for a given channel from the detection vector for that channel, one need only focus on designing a set of orthogonal detection vectors. To create a set of M channels of length N, a set of detection vectors are created which are mutually orthogonal. It will be understood by those skilled in the art that these vectors need only be linearly independent, but orthogonal patterns are desirable because they simplify the detection procedure. The orthogonality constraint can be stated mathematically by collecting the detection vectors into an N×M detection matrix D such that: D=[d 1 d 2 . . . d M ],  (5) with the orthogonality constraint expressed as: D T D=NI.   (6) The constraint that p 0 and p 1 for any of the channels have as many 1s as −1s can be alternatively stated as a requirement that the elements of the vector sum to zero; or, if 1 is an N-dimensional vector containing all ones, then p 0 T 1=p 1 T 1=1. Equation (1) implies that d j T 1=0 for all j so that D T 1==0  (7) The constraint that p 0 and p 1 each have exactly N/2 non-zero elements is equivalent to requiring that the inner products p 0 T q=p 1 T q=N/2. Applying equation (1) now leads to the constraint on d j that d j T q=0, which implies that: D T q= 0  (8) Equations (6)-(8) comprise all of the design constraints on finding a set of detection vectors. Any given detection vector d j must be orthogonal to all other vectors, as well as to 1 and q, so that: [ d 1 d 2 . . . d j−1 d j+1 . . . d M q 1] T d j =0  (9) Since it is only possible for a d j of dimension N to be orthogonal to an N−1 dimensional subspace, the maximum size of the matrix on the left side of equation (9) is N−1×N. Since two of the columns in the matrix are not d vectors, it follows that the maximum value of M is N−2. Accordingly, the problem is to find an orthonormal set of M=N−2 vectors of length N containing the values +1 and −1 that satisfy the constraints of equations (7) and (8). A set of detection vectors that meets these design constraints can be found by a brute-force search of possible patterns. This was done for the original TWACS design where N=8, which produces 6 different possible sets of 6 orthogonal channels. However, since the computational complexity of such a search is proportional to 2N, this approach quickly becomes unrealistic for larger values of N. Another way of finding valid sets of orthogonal detection vectors is to make use of existing orthogonal designs such as Hadamard matrices as discussed hereinafter. A Hadamard matrix is defined as an n×n matrix H containing only the elements 1 and −1, such that HH T =nI n The size n of a Hadamard matrix must be 1, 2, or an integer multiple of 4. It has been conjectured, but not yet proven, that Hadamard matrices exist for n equal to all integer multiples of 4. For designing TWACS transmission schemes, it is sufficient that there are known Hadamard matrix designs for relatively small n. For sizes where n=2 k , there is a method for constructing a Hadamard matrix. It can be shown that if H is a Hadamard matrix of order n, the matrix [   H H H - H ] is a Hadamard matrix of order 2n. Given this identity, and the fact that H 1 =1 is a Hadamard matrix of order 1, it follows that H 2 = [ 1 1 1 - 1 ] and that a Hadamard matrix of order 2 k can be constructed by repeated applications of the following: H 2 k = [ H 2 k - 1 H 2 k - 1 H 2 k - 1 - H 2 k - 1 ] = H 2 ⊗ H 2 k - 1 , where is the Kronecker product. Using a Hadamard matrix of size n to generate a set of detection vectors for TWACS signaling requires the detection vectors to be mutually orthogonal to each other, and to the vectors [q 1]. This is achieved by insuring that two of the columns of H are respectively equal to q and 1. Then, discarding those two columns and setting detection matrix D to the remaining columns of H, yields the desired N−2 orthogonal detection vectors. If the matrix already contains 1 and q as two of its columns, such as would occur when using the construction method outlined above, then the set of detection vectors is complete. Since many Hadamard matrices do not already contain the vectors 1 and q, the matrix must be modified to meet these conditions. This can be done by permuting rows or columns in the matrix, or inverting the sign of entire rows or columns therein. Either approach preserves the orthogonality properties of the Hadamard matrix. Many Hadamard matrices contain 1 as one of their columns, but where they do not, a column containing all ones can be created by inverting the signs of some of the rows in the matrix. For matrices that do not contain q as one of their columns, it is possible to permute rows of the matrix until one of the columns is equal to q. For example, take a Hadamard matrix of order 12: H 12 = [ 1 1 1 1 1 1 1 1 1 1 1 1 1 - 1 1 - 1 1 1 1 - 1 - 1 - 1 1 - 1 1 - 1 - 1 1 - 1 1 1 1 - 1 - 1 - 1 1 1 1 - 1 - 1 1 - 1 1 1 1 - 1 - 1 - 1 1 - 1 1 - 1 - 1 1 - 1 1 1 1 - 1 - 1 1 - 1 - 1 1 - 1 - 1 1 - 1 1 1 1 - 1 1 - 1 - 1 - 1 1 - 1 - 1 1 - 1 1 1 1 1 1 - 1 - 1 - 1 1 - 1 - 1 1 - 1 1 1 1 1 1 - 1 - 1 - 1 1 - 1 - 1 1 - 1 1 1 1 1 1 - 1 - 1 - 1 1 - 1 - 1 1 - 1 1 - 1 1 1 1 - 1 - 1 - 1 1 - 1 - 1 1 1 1 - 1 1 1 1 - 1 - 1 - 1 1 - 1 - 1 ] The matrix contains 1 as one of its columns, but does not contain q. By arbitrarily selecting the second column as the one to be modified to equal q, and by re-ordering the rows of H12, it is possible to create a matrix that contains 1 as its first column and q as its second column as shown below: H 12 = [ 1 1 1 1 1 1 1 1 1 1 1 1 1 - 1 1 - 1 1 1 1 - 1 - 1 - 1 1 - 1 1 1 - 1 - 1 1 - 1 1 1 1 - 1 - 1 - 1 1 - 1 - 1 1 - 1 1 1 1 - 1 - 1 - 1 1 1 1 - 1 - 1 - 1 1 - 1 - 1 1 - 1 1 1 1 - 1 1 - 1 - 1 1 - 1 1 1 1 - 1 - 1 1 1 1 - 1 - 1 - 1 1 - 1 - 1 1 - 1 1 1 - 1 - 1 1 - 1 - 1 1 - 1 1 1 1 - 1 1 1 1 1 - 1 - 1 - 1 1 - 1 - 1 1 - 1 1 - 1 - 1 - 1 1 - 1 - 1 1 - 1 1 1 1 1 1 - 1 1 1 1 - 1 - 1 - 1 1 - 1 - 1 1 - 1 1 1 1 - 1 - 1 - 1 1 - 1 - 1 1 ] A set of ten (10) detection vectors for a TWACS transmission scheme involving 12 half-cycles of an AC waveform can then be taken from columns 3-12 of matrix H 12 . The frequency content of TWACS inbound signals is different for each TWACS channel. The content is specified by two components: the shape of the pulses and the repetition patterns of the pulses. The pulse shapes are not a function of the particular channel, but of the power-line and local characteristics where the transponder is generating its signal. The inbound signal can be modeled as a convolution of the pulse shape with a series of impulses, so we can treat the frequency content of a particular channel as the product of the frequency content of the channel pattern and the frequency content of the pulse shape. Since detection vectors are matched filters for each channel, the frequency content of each channel is found by computing the Fourier transform of the detection vector. FIG. 2 shows the frequency content of signals for channel set A in the current TWACS protocol on a power distribution system with a 60 Hz AC frequency. The frequency responses shown in FIG. 2 end at 120 Hz because they are periodic with a period of 120 Hz. Therefore, the frequency content between 120-240 Hz is the same as that between 0-60 Hz, and so forth. Note that for a 50 Hz AC frequency, the spectral shape of each of the channels would be the same, but periodic with a period of 100 Hz instead. It will be noted that for each channel shown in FIG. 2 , the majority of its energy occurs at slightly different frequencies from the other channels. This helps explain some of the differences in performance sometimes seen between one channel and another. Heretofore, channel 1 has been observed as having the worst performance. In FIG. 2 , it is seen that channel 1 has most of its energy near 60 Hz. This implies that, at higher frequencies, most of its energy is close to the odd harmonics of 60 Hz which adversely affects signal detection because it is common to find increased noise levels near the odd harmonics of the AC frequency. In addition to signal detection problems, placing significant energy near 60 Hz also causes the additional problem of light flicker. Light flicker is caused by low-frequency modulation of the AC signal used to power incandescent light bulbs. Placing significant signal energy near the AC frequency is effectively the equivalent of modulating the at a low frequency; so, channels with the most energy near the AC frequency are those most prone to light flicker. This effect can be reduced by modifying the shape of inbound pulses to reduce their low-frequency content; but problems associated with placing signal energy near odd harmonics remain. The connection between frequency content of a channel and its detection vector can be seen by observing that channels 4 and 6 in FIG. 2 have most of their energy concentrated at low frequencies, and that the corresponding detection vectors listed in Table 2 have few sign changes. A detection vector with few sign changes is analogous to a low frequency Fourier transform basis function. The connection between the number of sign changes in a vector and frequency is referred to as “sequency”. Hadamard matrices constructed in accordance with the method described above can be ordered in sequency order by indexing them using Gray codes with a bit-reversed order; that is, the most significant bit is incremented first. Referring to FIG. 3 , what is shown is a comparison of a sequency ordered Hadamard matrix and a discrete cosine transform (DCT) matrix, both of size 64. The DCT matrix is a real valued transform with properties similar to a Fourier transform. In the FIG. 3 comparison, the sequency-ordered Hadamard matrix has a structure similar to that of the DCT matrix. In this ordering, the first vector corresponds to direct current (DC) and the last vector to the vector q, the two vectors that do not meet the design constraint. With the first and last vectors removed (because they correspond to vectors q and 1), the actual frequency content of the remaining 14 vectors for a length of 16 is illustrated in FIG. 4 . Here, the first detection vectors have their frequency content concentrated close to DC, while the last vectors have their frequency content concentrated close to 60 Hz; and, by extension, its odd harmonics. From the previous discussion of desirable properties of TWACS channels, it will be understood that this ordering puts the channels in order of desirability. Accordingly, future channel sets are defined in sequency order. In situations where not all channels are required, the channels should be used in an order such that the last and least desirable channel is the least frequently used. Since there exist N−2 viable pulse patterns of length N, the aggregate throughput of a TWACS system with length N pulse patterns will be N - 2 N ⁢ 2 ⁢ ⁢ f , where f is the AC frequency, and 2f the number of half-cycles per second. Because of this, the ratio (N−2)/N can be thought of as the efficiency of the channel set of length N, and the ratio asymptotically approaches 1 as N becomes large. As an example, the efficiency of channel sets of length 8 is 3/4, while that of channel sets of length 16 is 7/8. This increased efficiency makes it possible to completely avoid some channels yet still obtain the same efficiency as a smaller channel set. Thus, an efficiency of 3/4 can still be maintained even if channels 13 and 14, the two least desirable channels in channel set 16, are not used. Taken even further, with a channel set 32, channels 25-30 could all be avoided while still maintaining an efficiency of 3/4. The principles previously set forth for designing a general set of detection vectors and pulse patterns assumed there is one time slot per half cycle of the AC waveform for transmitting a current pulse. A way of increasing the data rate of TWACS is to “squeeze” more than one pulse into each half cycle. This is not currently possible when a silicon-controlled rectifier (SCR) is used as the switching device to insert a load into the circuit, but there are other alternatives which make this possible. Since this scenario will change some of the underlying assumptions for designing pulse patterns, the design procedure needs to be modified accordingly. Consider, for example, the situation where there are two pulses per half-cycle. Here, the evenly spaced pulses at π/4, 3π/4, 5π/4, and 7π/4 radians all yield roughly the same amplitude. This scenario does not change equation (1), but does change the definition of q in equation (2). Now, the signs in q must match the polarity of the transmitted pulses, so q will be: q=[ 1 1 −1 −1 1 . . . ] T . Again, a Hadamard matrix of size N can be arranged so it contains the vectors 1 and the new definition of q, and these two vectors are removed to give the final set of detection vectors. For a sequency-ordered Hadamard matrix of size 16, instead of deleting rows 1 and 16, rows 1 and 8 are now deleted. From this matrix, the pulse patterns p 0 and p 1 for transmitting “0” and “1” are derived by again applying equations (3) and (4) using the new definition of q. FIG. 5 shows the frequency response with 2 pulses per half-cycle of rows 2, 9, 15, and 16 of the sequency-ordered Hadamard matrix of size 16. It will be noted that instead of being periodic every 120 Hz, the frequency response is now periodic every 240 Hz. However, this causes some additional problems because, although they meet the initial design constraints, the frequency characteristics of rows 9 and 16 show that they carry all of their information content in the odd and even harmonics of 60 Hz, respectively. The relative strength of TWACS inbound signals relative to harmonics of the AC waveform is low enough that placing the energy at these harmonics makes the signals very difficult to detect. Accordingly, those rows in the Hadamard matrix should not be used. This means rows 1, 8, 9, and 16 are not used which leaves a total of 12 out of 16 channels and an efficiency of 3/4. With the sequency-ordered Hadamard matrix, each row has a frequency characteristic with a peak that progresses from DC in the first row, to 60 Hz for the last row. Now that the progression is from 0 to 120 Hz, the last row avoids putting energy near 60 Hz just as well as the first row. This implies that if we continue to define desirability of a channel in terms of the amount of energy placed near 60 Hz, the sequency-ordered Hadamard matrix should be reordered as follows: {1 ,N, 2 ,N− 1 , . . . ,N/ 2−1 ,N/ 2+2 ,N/ 2 ,N/ 2+1} With this ordering, the first two rows and last two rows are the ones deleted, leaving the remaining detection vectors in order of preference. This same procedure can also be applied to longer vectors for values of N=2 k with the same results. The significance of this is that for a general TWACS-like transmission scheme involving two pulses per half-cycle, every set of pulse patterns of length N will have a length N−4, and the efficiency of the channel set will be N - 4 N . Efficiency is now multiplied by 4f instead of 2f in this instance in order to obtain maximum achievable throughput. What has been described is a general scheme for designing detection vectors and pulse patterns of any length of a TWACS inbound transmission. Inbound transmissions using current pulses involve a few design constraints, which, in turn, impose limits on the number of channels that can be created of a particular length. These design constraints can, however, be met by manipulating Hadamard matrices of the desired size. Finally, proposed channel patterns of lengths 16 and 32 are presented in the following tables. These were constructed using sequency-ordered Hadamard matrices in which the first and last vectors which do not meet the design constraints are dropped. The result is a set of channels ordered in their approximate order of desirability, with the first channels minimizing the energy near 60 Hz and the odd harmonics thereof, and the last channels containing significant energy near those frequencies. For patterns of length 16, Tables 3 and 4 present the pulse patterns for transmitting a “0” and “1”, respectively. Table 5 presents the corresponding detection vectors. For patterns of length 32, Tables 6 and 7 present pulse patterns for transmitting a “0” and “1”, respectively. Table 8 presents the corresponding detection vectors. TABLE 3 Channel Set 16, Pulse Patterns for Logical “0” Channel # Pattern 1 0 −1 0 −1 0 −1 0 −1 1 0 1 0 1 0 1 0 2 0 −1 0 −1 1 0 1 0 1 0 1 0 0 −1 0 −1 3 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 4 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 5 0 −1 1 0 1 0 0 −1 1 0 0 −1 0 −1 1 0 6 0 −1 1 0 0 −1 1 0 1 0 0 −1 1 0 0 −1 7 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 8 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 9 0 0 1 −1 0 0 1 −1 1 −1 0 0 1 −1 0 0 10 0 0 1 −1 1 −1 0 0 1 −1 0 0 0 0 1 −1 11 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 12 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 13 0 0 0 0 1 −1 1 −1 1 −1 1 −1 0 0 0 0 14 0 0 0 0 0 0 0 0 1 −1 1 −1 1 −1 1 −1 TABLE 4 Channel Set 16, Pulse Patterns for Logical “1” Channel # Pattern 1 1 0 1 0 1 0 1 0 0 −1 0 −1 0 −1 0 −1 2 1 0 1 0 0 −1 0 −1 0 −1 0 −1 1 0 1 0 3 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 4 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 5 1 0 0 −1 0 −1 1 0 0 −1 1 0 1 0 0 −1 6 1 0 0 −1 1 0 0 −1 0 −1 1 0 0 −1 1 0 7 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 8 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 9 1 −1 0 0 1 −1 0 0 0 0 1 −1 0 0 1 −1 10 1 −1 0 0 0 0 1 −1 0 0 1 −1 1 −1 0 0 11 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 12 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 13 1 −1 1 −1 0 0 0 0 0 0 0 0 1 −1 1 −1 14 1 −1 1 −1 1 −1 1 −1 0 0 0 0 0 0 0 0 TABLE 5 Channel Set 16, Detection Vectors Channel # Pattern 1 1 1 1 1 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 2 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 3 1 1 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 4 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 5 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1 1 1 −1 −1 6 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1 7 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 8 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 9 1 −1 −1 1 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1 10 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1 1 −1 −1 1 11 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 12 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 13 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 1 −1 1 −1 14 1 −1 1 −1 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 TABLE 6 Channel Set 32, Pulse Patterns for Logical “0” Channel # Pattern 1 0 −1 0 −1 0 −1 0 −1 0 −1 0 −1 0 −1 0 −1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 2 0 −1 0 −1 0 −1 0 −1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 0 −1 0 −1 0 −1 0 −1 3 0 −1 0 −1 0 −1 0 −1 1 0 1 0 1 0 1 0 0 −1 0 −1 0 −1 0 −1 1 0 1 0 1 0 1 0 4 0 −1 0 −1 1 0 1 0 1 0 1 0 0 −1 0 −1 0 −1 0 −1 1 0 1 0 1 0 1 0 0 −1 0 −1 5 0 −1 0 −1 1 0 1 0 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 0 −1 0 −1 1 0 1 0 6 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 7 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 8 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 9 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 10 0 −1 1 0 1 0 0 −1 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 0 −1 1 0 1 0 0 −1 11 0 −1 1 0 1 0 0 −1 1 0 0 −1 0 −1 1 0 0 −1 1 0 1 0 0 −1 1 0 0 −1 0 −1 1 0 12 0 −1 1 0 0 −1 1 0 1 0 0 −1 1 0 0 −1 0 −1 1 0 0 −1 1 0 1 0 0 −1 1 0 0 −1 13 0 −1 1 0 0 −1 1 0 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 0 −1 1 0 0 −1 1 0 14 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 15 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 16 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 17 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 18 0 0 1 −1 0 0 1 −1 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 0 0 1 −1 0 0 1 −1 19 0 0 1 −1 0 0 1 −1 1 −1 0 0 1 −1 0 0 0 0 1 −1 0 0 1 −1 1 −1 0 0 1 −1 0 0 20 0 0 1 −1 1 −1 0 0 1 −1 0 0 0 0 1 −1 0 0 1 −1 1 −1 0 0 1 −1 0 0 0 0 1 −1 21 0 0 1 −1 1 −1 0 0 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 0 0 1 −1 1 −1 0 0 22 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 23 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 24 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 25 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 26 0 0 0 0 1 −1 1 −1 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 0 0 0 0 1 −1 1 −1 27 0 0 0 0 1 −1 1 −1 1 −1 1 −1 0 0 0 0 0 0 0 0 1 −1 1 −1 1 −1 1 −1 0 0 0 0 28 0 0 0 0 0 0 0 0 1 −1 1 −1 1 −1 1 −1 0 0 0 0 0 0 0 0 1 −1 1 −1 1 −1 1 −1 29 0 0 0 0 0 0 0 0 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 0 0 0 0 0 0 0 0 30 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 TABLE 7 Channel Set 32, Pulse Patterns for Logical “1” Channel # Pattern 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 0 −1 0 −1 0 −1 0 −1 0 −1 0 −1 0 −1 0 −1 2 1 0 1 0 1 0 1 0 0 −1 0 −1 0 −1 0 −1 0 −1 0 −1 0 −1 0 −1 1 0 1 0 1 0 1 0 3 1 0 1 0 1 0 1 0 0 −1 0 −1 0 −1 0 −1 1 0 1 0 1 0 1 0 0 −1 0 −1 0 −1 0 −1 4 1 0 1 0 0 −1 0 −1 0 −1 0 −1 1 0 1 0 1 0 1 0 0 −1 0 −1 0 −1 0 −1 1 0 1 0 5 1 0 1 0 0 −1 0 −1 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 1 0 1 0 0 −1 0 −1 6 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 7 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 8 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 9 1 0 0 −1 0 −1 1 0 1 0 0 −1 0 −1 1 0 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 10 1 0 0 −1 0 −1 1 0 0 −1 1 0 1 0 0 −1 0 −1 1 0 1 0 0 −1 1 0 0 −1 0 −1 1 0 11 1 0 0 −1 0 −1 1 0 0 −1 1 0 1 0 0 −1 1 0 0 −1 0 −1 1 0 0 −1 1 0 1 0 0 −1 12 1 0 0 −1 1 0 0 −1 0 −1 1 0 0 −1 1 0 1 0 0 −1 1 0 0 −1 0 −1 1 0 0 −1 1 0 13 1 0 0 −1 1 0 0 −1 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 1 0 0 −1 1 0 0 −1 14 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 15 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 1 0 0 −1 16 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 17 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 18 1 −1 0 0 1 −1 0 0 0 0 1 −1 0 0 1 −1 0 0 1 −1 0 0 1 −1 1 −1 0 0 1 −1 0 0 19 1 −1 0 0 1 −1 0 0 0 0 1 −1 0 0 1 −1 1 −1 0 0 1 −1 0 0 0 0 1 −1 0 0 1 −1 20 1 −1 0 0 0 0 1 −1 0 0 1 −1 1 −1 0 0 1 −1 0 0 0 0 1 −1 0 0 1 −1 1 −1 0 0 21 1 −1 0 0 0 0 1 −1 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 1 −1 0 0 0 0 1 −1 22 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 23 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 24 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 25 1 −1 1 −1 0 0 0 0 1 −1 1 −1 0 0 0 0 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 26 1 −1 1 −1 0 0 0 0 0 0 0 0 1 −1 1 −1 0 0 0 0 1 −1 1 −1 1 −1 1 −1 0 0 0 0 27 1 −1 1 −1 0 0 0 0 0 0 0 0 1 −1 1 −1 1 −1 1 −1 0 0 0 0 0 0 0 0 1 −1 1 −1 28 1 −1 1 −1 1 −1 1 −1 0 0 0 0 0 0 0 0 1 −1 1 −1 1 −1 1 −1 0 0 0 0 0 0 0 0 29 1 −1 1 −1 1 −1 1 −1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 −1 1 −1 1 −1 1 −1 30 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 TABLE 8 Channel Set 32, Detection Vectors Channel # Pattern 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 2 1 1 1 1 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 1 1 1 1 3 1 1 1 1 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 4 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 5 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 1 1 1 1 1 1 −1 −1 −1 −1 6 1 1 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 1 1 7 1 1 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 8 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 9 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 10 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1 11 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1 1 1 −1 −1 12 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1 13 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 1 1 −1 −1 1 1 −1 −1 14 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 15 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 16 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 17 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 18 1 −1 −1 1 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 1 −1 −1 1 1 −1 −1 1 19 1 −1 −1 1 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1 1 −1 −1 1 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1 20 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1 1 −1 −1 1 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1 1 −1 −1 1 21 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 1 −1 −1 1 −1 1 1 −1 22 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 23 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 24 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 25 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 26 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 1 −1 1 −1 −1 1 −1 1 27 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 1 −1 1 −1 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 1 −1 1 −1 28 1 −1 1 −1 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 1 −1 1 −1 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 29 1 −1 1 −1 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 1 −1 1 −1 1 −1 1 −1 30 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1

A method for producing a set of inbound pulse patterns and detection vectors for lengths longer than 4 cycles in an AC waveform. These are used for generating inbound messages in a two-way automatic communication system (TWACS). The method uses Hadamard matrices adapted to generate a set of detection vectors by permuting rows of a matrix and removing certain columns of the matrix to meet system design requirements. The method can be extended to any length and modified to accommodate multiple pulses per half-cycle to support higher data rates.

RELATED APPLICATIONS This application is a continuation application of application Ser. No. 10/978,101 filed Oct. 29, 2004, pending, which is a continuation application of application Ser. No. 10/346,338, filed on Jan. 16, 2003 now abandoned, which is a continuation of application Ser. No. 09/739,089, filed on Dec. 15, 2000, pending, which in turn claims priority to Greek National Application Serial No. 20000/100102 filed on Mar. 28, 2000. The contents of all of the aforementioned application(s) are hereby incorporated by reference. FIELD OF THE INVENTION The present invention is directed to a method and apparatus for the in vivo, non invasive detection and mapping of the biochemical and/or functional pathologic alterations of human tissues. BACKGROUND OF THE INVENTION Cancer precursors signs are the so called pre-cancerous states, which are curable if they are detected at an early stage. In the opposite case the lesion can progress in depth, resulting in the development of invasive cancer and metastases. At this stage, the possibilities of successful therapy are dramatically diminished. Consequently, the early detection and the objective identification of the severity (stage) of the precancerous lesion are of crucial importance. The conventional clinical process of optical examination have very limited capabilities in detecting cancerous and pre-cancerous tissue lesions. This is due to the fact that the structural and metabolic changes, which take place during the development of the decease, do not significantly and with specificity alter the color characteristics of the pathological tissue. In order to obtain more accurate diagnosis, biopsy samples are obtained from suspicious areas, which are submitted for histological examination. However, biopsy sampling poses several problems, such as: a) risk for sampling errors associated with the visual limitations in detecting and localizing suspicious areas; b) biopsy can alter the natural history of the intraepithelial lesion; c) mapping and monitoring of the lesion require multiple tissue sampling, which is subjected to several risks and limitations; d) the diagnostic procedure performed with biopsy sampling and histologic evaluation is qualitative, subjective, time consuming, costly and labor intensive. In recent years there have been developed and presented quite a few new methods and systems in an effort to overcome the disadvantages of the conventional diagnostic procedures. These methods can be classified in two categories: a) Methods which are based on the spectral analysis of tissues in vivo, in an attempt to improve the diagnostic information b) Methods which are based on the chemical excitation of tissues with the aid of special agents, which have the property to interact with pathologic tissue and to alter its optical characteristics selectively, thus enhancing the contrast between lesion and healthy tissue. In the first case, the experimental use of spectroscopic techniques as a potential solutions to existing diagnostic problems, is motivated by their capability to detect alterations in the biochemical and/or the structural characteristics, which take place in the tissue during the development of the disease. In particular, fluorescence spectroscopy has been extensively used in various tissues, where the later are optically excited with the aid of a light source (usually laser), of short wave length (blue—ultraviolet range) and their response is measured as fluorescence intensity vs. wavelength. Garfield and Glassman in U.S. Pat. No. 5,450,857 and Ramanajum et al in U.S. Pat. No. 5,421,339 have presented a method based on the use of fluorescence spectroscopy for the diagnosis of cancerous and pre-cancerous lesions of cervix. The main disadvantage of fluorescence spectroscopy is that the existing biochemical modifications associated with the progress of the disease are not manifested in a direct way as modifications in the measured fluorescence spectra. The fluorescence spectra contain limited diagnostic information of two basic reasons: a) Tissues contain non-fluorescent chromophores, such as hemoglobin. Absorption by such chromophores of the emitted light from fluorophores can result in artificial dips and peaks in the fluorescence spectra. In other words the spectra carry convoluted information for several components and therefore it is difficult assess alterations in tissue features of diagnostic importance; and b) The spectra are broad due to the fact that a large number of tissue components are optically excited and contribute to the captured optical signal. As a result the spectra do not carry specific information for the pathologic alterations and thus they are of limited diagnostic value. The latter is expressed as low sensitivity and specificity in the detection and classification of tissue lesions. Aiming to enhance the sensitivity and specificity of the captured information, Ramanujan et al in the Patent No. WO 98/24369 have presented a method based on the use of neural networks for the analysis of the spectral data. This method is based on the training of a computing system with a large number of spectral patterns, which have been taken from normal and from pathologic tissues. The spectrum that is captured each time is compared with the stored spectral data, facilitating this way, the identification of the tissue pathology. R. R. Kortun et al, in U.S. Pat. No. 5,697,373, seeking to improve the captured diagnostic information, have presented a method based on the combination of fluorescence spectroscopy and Raman scattering. The last has the capability of providing more analytical information, it requires however complex instrumentation and ideal experimental conditions, which substantially hinder their clinical use. It is generally known that tissues are characterized by the lack of spatial homogeneity and consequently the spectral analysis of distributed spatial points is insufficient for the characterization of their status. Dombrowski in U.S. Pat. No. 5,424,543, describes a multi-wavelength, imaging system, capable of capturing tissue images in several spectral bands. With the aid of such a system it is possible in general to map characteristics of diagnostic importance based on their particular spectral characteristics. However, due to the insignificance of the spectral differences between normal and pathologic tissue, which is in general the case, inspection in narrow spectral bands does not allow the highlighting of these characteristics and even more so, the identification and staging of the pathologic area. D. R. Sandison et al, in U.S. Pat. No. 5,920,399 describe an imaging system, developed for the in vivo investigation of cells, which combines multi-band imaging and light excitation of the tissue. The system also employs a dual fiber optic bundle for the transferring of the emitted from the source light onto the tissue and the remitted light from the tissue to the optical detector. These bundles are placed in contact with the tissue, and various wavelengths of excitation and imaging are combined in attempt to enhance the spectral differentiation between normal and pathologic tissue. In U.S. Pat. No. 5,921,926, J. R. Delfyett et al have presented a method for the diagnosis of diseases of the cervix, which is based on the combination of Spectral Interferometry and Optical Coherence Tomography (OCT). This system combines three-dimensional imaging and spectral analysis of the tissue. Moreover, several improved versions of colposcopes have been presented, (D. R. Craine et al, U.S. Pat. No. 5,791,346 and K. L. Blaiz U.S. Pat. No. 5,989,184) in most of which, electronic imaging systems have been integrated for image capturing, analysis of tissue images, including the quantitative assessment of lesion's size. For the enhancement of the optical differentiation between normal and pathologic tissue, special agents are used in various fields of biomedical diagnostics, which are administered topically or systematically. Such agents are acetic acid solution, toluidine blue, various photosensitizers (porphyrines) (S. Anderson Engels, C. Klinteberg, K. Svanberg, S. Svanberg, In vivo fluorescence imaging for tissue diagnostics, Phys Med. Biol. 42 (1997) 815-24). The provoked selective staining of the pathologic tissue is owed to the property of these agents to interact with the altered metabolic and structural characteristics of the pathologic area. This interaction enhances progressively and reversibly the differences in the spectral characteristics of reflection and/or fluorescence between normal and pathologic tissue. Despite the fact that the provoked selective staining of the pathologic tissue is a dynamic phenomenon, in clinical practice the intensity and the extent of the staining are assessed qualitatively and statically. Furthermore, in several cases of early pathologic conditions, the phenomenon of temporary staining after administering the agent, is short-lasting and thus the examiner is not able to detect the provoked alterations and even more so, to assess their intensity and extent. In other cases, the staining of the tissue progresses very slowly, with the consequence of patient discomfort and creation of problems for the examiner in assessing the intensity and extent of the alterations, since they are continuously changing. The above have as direct consequence, the downgrading of the diagnostic value of these diagnostic procedures and thus its usefulness is limited to facilitate the localization of suspected areas for obtaining biopsy samples. Summarizing the above mentioned, the following conclusions are drawn: a) Various conventional light dispersion spectroscopic techniques (fluorescence, elastic, non elastic scattering, etc) have been proposed and experimentally used for the in vivo detection of alterations in the structural characteristics of pathologic tissue. The main disadvantage of these techniques is that they provide point information, which is inadequate for the analysis of the spatially non-homogenous tissue. Multi-band imaging has the potential to solve this problem, by providing spectral information (of lesser resolution as a rule) but in any spatial point of the area under examination. These techniques (imaging and non-imaging) however, provide information of limited diagnostic value, due to the fact that the structural tissue alterations, which are accompanying the development of the disease, are not manifested as significant and characteristic alterations on the measured spectra. Consequently, the captured spectral information cannot be directly correlated with the tissue pathology, a fact which limits the clinical usefulness of these techniques. b) The conventional (non-spectral) imaging techniques provide the capability of mapping characteristics of diagnostic importance in two or three dimensions. They are basically used for measuring morphological characteristics and as clinical documentation tools. c) The diagnostic methods which are based on the selective staining of pathologic tissue with special agents allows the enhancement of the optical contrast between normal and pathologic tissue. Nevertheless they provide limited information for the in vivo identification and staging of the disease. Given the fact that the selective interaction of pathologic tissue with the agents, which enhance its optical contrast with healthy tissue is a dynamic phenomenon, it is reasonable to suggest that the capture and analysis of the characteristics of this phenomenon's kinetics, could provide important information for the in vivo detection, identification and staging of tissue lesions. In a previous publication by the inventors (C. Balas, A. Dimoka, E. Orfanoudaki, E. koumandakis, “In vivo assessment of acetic acid-cervical tissue interaction using quantitative imaging of back-scattered light: Its potential use for the in vivo cervical cancer detection grading and mapping”, SPIE-Optical Biopsies and Microscopic Techniques, Vol. 3568 pp. 31-37, (1998)), measurements of the alterations in the characteristics of the back-scattered light as a function of wave-length and time are presented. These alterations are provoked in the cervix by the topical administration of acetic acid solution. In this particular case, there was used as an experimental apparatus, a general-purpose multi-spectral imaging system built around a tunable liquid crystal monochromator for measuring the variations in intensity of the back-scattered light as a function of time and wavelength in selected spatial points. It was found that the lineshapes of curves of intensity of back-scattered light versus time, provide advanced information for the direct identification and staging of tissue neoplasias. Unpublished results of the same research team support that similar results can also be obtained with other agents, which have the property of enhancing the optical contrast between normal and pathologic tissue. Nevertheless, the experimental method employed in the published paper is characterized by quite a few disadvantages, such as: The imaging monochromator requires time for changing the imaging wavelength and as a consequence it is inappropriate for multispectral imaging and analysis of dynamic phenomena. It does not constitute a method for the mapping of the grade of the tissue lesions, as the presented curves illustrate the temporal alterations of intensity of the back-scattered light in selected points. The lack of data modeling and parametric analysis of the characteristics of the phenomenon kinetics in any spatial point of the area of interest restrict the usefulness of the method in experimental studies and hinder its clinical implementation. The optics used for the imaging of the area of interest are of general purpose and are not comply with the special technical requirements for the clinical implementation of the method. Clinical implementation of the presented system is also hindered by the fact that it does not integrate appropriate means for ensuring the stability of the relative position between the tissue surface and image capturing module, during the snapshot imaging procedure. This is very important since small movements of the patient (i.e. breathing) are always present during the examination procedure. If micro-movements are taking place during successive capturing of images, after application of the agent, then the spatial features of the captured images are not coincide. This reduces substantially the precision in the calculation of the curves in any spatial point, that express the kinetics of marker-tissue interaction. SUMMARY OF THE INVENTION The present invention provides, at least in part, a method for monitoring the effects of a pathology differentiating agent on a tissue sample by applying a pathology differentiating agent, e.g., acetic acid, on a tissue sample and monitoring the rate of change of light reflection from the tissue sample over time, thereby monitoring the effects of a pathology differentiating agent on a tissue sample. The tissue may be a cervical, ear, oral, skin, esophagus, or stomach tissue. Without intending to be limited by theory, it is believed that the pathology differentiating agent provokes transient alterations in the light scattering properties of the tissue, e.g., the abnormal epithelium. In another aspect, the present invention features a method for the in vivo diagnosis of a tissue abnormality, e.g., a tissue atypia, a tissue dysplasia, a tissue neoplasia (such as a cervical intraepithelial neoplasia, CINI, CINII, CIMIII) or cancer, in a subject. The method includes contacting a tissue in a subject with a pathology differentiating agent, e.g., an acetic acid solution or a combination of solutions selected from a plurality of acidic and basic solutions, exposing the tissue in the subject to optical radiation; and monitoring the intensity of light emitted from the tissue over time, thereby diagnosing a tissue abnormality in a subject. The optical radiation may be broad band optical radiation, preferably polarized optical radiation. The non-invasive methods of the present invention are useful for the in vivo early detection of tissue abnormalities/alterations and mapping of the grade of these tissue abnormalities/alterations, caused in the biochemical and/or in the functional characteristics of epithelial tissues, during the development of tissue atypias, dysplasias, neoplasias and cancers. In one embodiment, the tissue area of interest is illuminated with a broad band optical radiation and contacted with a pathology differentiating agent, e.g., an agent or a combination of agents which interact with pathologic tissue areas characterized by an altered biochemical composition and/or cellular functionality and provoke a transient alteration in the characteristics of the light that is re-emitted from the tissue. The light that is re-emitted from the tissue may be in the form of reflection, diffuse scattering, fluorescence or combinations or subcombinations thereof. The intensity of the light emitted from the tissue may be measured, e.g., simultaneously, in every spatial point of the tissue area of interest, at a given time point or over time (e.g., for the duration of agent-tissue interaction). A diagnosis may be made based on the quantitative assessment of the spatial distribution of alterations in the characteristics of the light re-emitted from the tissue at given time points, before and after the optical and chemical excitation of the tissue and/or based on the quantitative assessment of the spatial distribution of parameters, calculated from the characteristic curves that express the kinetics of the provoked alterations in the characteristics of the light re-emitted from the tissue, which characteristic curves are simultaneously measured in every spatial point of the area under examination during the optical and chemical excitation of the tissue. In one embodiment of the invention, the step of tissue illumination comprises exposing the tissue area under analysis to optical radiation of narrower spectral width than the spectral width of the light emitted by the illumination source. In another embodiment, the step of measuring the intensity of light comprises measuring the intensity of the re-emitted light in a spectral band, the spectral width of which is narrower than the spectral width of the detector's sensitivity. In yet another embodiment, the step of measuring the intensity of light comprises measuring simultaneously the intensity of the re-emitted light in a plurality of spectral bands, the spectral widths of which are narrower than the spectral width of the detector's sensitivity. In yet another aspect, the present invention features an apparatus for the in vivo, non-invasive early detection of tissue abnormalities/alterations and mapping of the grade of these tissue abnormalities/alterations, caused in the biochemical and/or in the functional characteristics of epithelial tissues, during the development of tissue atypias, dysplasias, neoplasias and cancers. The apparatus includes optics for collecting the light re-emitted by the area under analysis, selecting magnification and focusing the image of the area; optical imaging detector(s); means for the modulation, transfer, display and capturing of the image of the tissue area of interest; a computer which includes data storage, processing and analysis means; a monitor for displaying images, curves and numerical data; optics for the optical multiplication of the image of the tissue area of interest; a light source for illuminating the area of interest; optionally, optical filters for selecting the spectral band of imaging and illumination; means for transmitting light and illuminating the area of interest; control electronics; and optionally, software for the analysis and processing of data, which also enables the tissue image capturing and storing in specific time points and for a plurality of time points, before and after administration of the pathology differentiating agent. Using the foregoing apparatus an image or a series of images may be created which express the spatial distribution of the characteristics of the kinetics of the provoked changes in the tissue's optical characteristics, before and after the administration of the agent, with pixel values corresponding with the spatial distribution of the alterations in the intensity of the light emitted from the tissue, in given time instances, before and after the optical and chemical excitation of tissue and/or with the spatial distribution of parameters derived from the function: pixel gray value versus time. The foregoing function may be calculated from the captured and stored images and for each row of pixels with the same spatial coordinates. In one embodiment, the step of optical filtering the imaging detector comprises an optical filter that is placed in the optical path of the rays that form the image of the tissue, for the recording of temporally successive images in a selected spectral band, the spectral width of which is narrower than the spectral width of the detector's sensitivity. In yet another embodiment, the image multiplication optics comprise light beam splitting optics that create two identical images of the area of interest, which are recorded by two imaging detectors, in front of which optical filters are placed, with in general different transmission characteristics and capable of transmitting light of spectral width shorter than the spectral width of the detector's sensitivity, so that two groups of temporally successive images of the same tissue area are recorded simultaneously, each one corresponding to a different spectral band. In another embodiment, the image multiplication optics comprise more than one beam splitter for the creation of multiple identical images of the area of interest, which are recorded by multiple imaging detectors, in front of which optical filters are placed, with, preferably, different transmission characteristics and capable of transmitting light of spectral width shorter than the spectral width of the detector's sensitivity, so that multiple groups of temporally successive images of the same tissue area are recorded simultaneously, each one corresponding to a different spectral band. In a further embodiment, the image multiplication optics comprise one beam splitter for the creation of multiple identical images of the area of interest, which are recorded by multiple imaging detectors, in front of which optical filters are placed with, preferably, different transmission characteristics and capable of transmitting light of spectral width shorter than the spectral width of the detector's sensitivity, so that multiple groups of temporally successive images of the same tissue area are recorded simultaneously, each one corresponding to a different spectral band. In yet a further embodiment, the image multiplication optics comprise one beam splitter for the creation of multiple identical images of the area of interest, which are recorded in different sub-areas of the same detector, and in front these areas optical filters are placed with, preferably, different transmission characteristics and capable of transmitting light of spectral width shorter than the spectral width of the detector's sensitivity, so that multiple groups of temporally successive images of the same tissue area are recorded simultaneously in the different areas of the detector, each one corresponding to a different spectral band. In another embodiment, the step of filtering the light source comprises an optical filter, which is placed in the optical path of an illumination light beam, and transmits light of spectral width shorter than the spectral width of sensitivity of the detector used. In a further embodiment, the step of filtering the light source comprises a plurality of optical filters and a mechanism for selecting the filter that is interposed to the tissue illumination optical path, thus enabling the tuning of the center wavelength and the spectral width of the light illuminating the tissue. In another embodiment, the mapping of the grade of the alterations to the biochemical and/or functional characteristics of the tissue area of interest, is based on the pixel values of one image, from the group of the recorded temporally successive images of the tissue area of interest. In a further embodiment, the mapping of the grade of the alterations to the biochemical and/or functional characteristics of the tissue area of interest, is based on the pixel values belonging to plurality of images, which are members of the group of the recorded temporally successive images of the tissue area of interest. In another embodiment, the mapping of the grade of the alterations to the biochemical and/or functional characteristics of the tissue area of interest, is based on numerical data derived from mathematical operations and calculations between the pixel values belonging a plurality of images, which are members of the group of the recorded temporally successive images of the tissue area of interest. In a further embodiment, a pseudo-color scale, which represents with different colors the different pixel values of the image or of the images used for the mapping of abnormal tissue areas, is used for the visualization of the mapping of the grade of the alterations to the biochemical and/or functional characteristics of the tissue area under examination. In one embodiment, the image or images which are determined for the mapping of the grade of the alterations in biochemical and/or functional characteristics of tissue, are used for the in vivo detection, mapping, as well as for the determination of the borders of epithelial lesions. In another embodiment, the pixel values of the image or of the images which are determined for the mapping of the grade of alterations in biochemical and/or functional characteristics of tissue, are used as diagnostic indices for the in vivo identification and staging of epithelial lesions. In yet another embodiment, the image or the images which are determined for the mapping of the grade of the alterations in biochemical and/or functional characteristics of tissue can be overimposed onto the color or black and white image of the same area of tissue under examination displayed on the monitor, so that abnormal tissue areas are highlighted and their borders are demarcated, facilitating the selection of a representative area for taking a biopsy sample, the selective surgical removal of the abnormal area and the evaluation of the accuracy in selecting and removing the appropriate section of the tissue. In a further embodiment, the image or the images which are determined for the mapping of the grade of alterations in biochemical and/or functional characteristics of tissue are used for the evaluation of the effectiveness of various therapeutic modalities such as radiotherapy, nuclear medicine treatments, pharmacological therapy, and chemotherapy. In another embodiment, the optics for collecting the light re-emitted by the area under analysis, comprises the optomechanical components employed in microscopes used in clinical diagnostic examinations, surgical microscopes, colposcopes and endoscopes. In one embodiment of the invention, for colposcopy applications, the apparatus may comprise a speculum, an articulated arm onto which the optical head is attached, which optical head comprises a refractive objective lens, focusing optics, a mechanism for selecting the magnification, an eyepiece, a mount for attaching a camera, and an illuminator, where the speculum is attached in a fixed location onto the system articulated arm-optical head, in such a way such that the central longitudinal axis of the speculum is perpendicular to the central area of the objective lens, so that when the speculum is inserted into the vagina and fixed in it, the relative position of the image-capturing optics and of the tissue area of interest remains unaltered, regardless of micro-movements of the cervix, which are taking place during the examination of the female subject. In a further embodiment, the apparatus may further comprise an atomizer for delivering the agent, where the atomizer is attached in a fixed point onto the system articulated arm-optical head of the apparatus and in front of the vaginal opening, where the spraying of the tissue may be controlled and synchronized with a temporally successive image capturing procedure, with the aid of electronic control means. In another embodiment of the apparatus of the invention, the image capturing detector means and image display means comprise a camera system with detector spatial resolution greater than 1000×1000 pixels and a monitor of at least 17 inches (diagonal), so that high magnification is ensured together with a large field of view, while the image quality is maintained. In a further embodiment, in the case of microscopes used in clinical diagnostic examinations, surgical microscopes and colposcopes, comprise an articulated arm onto which the optical head is attached, which optical head comprises an objective lens, focusing optics, a mechanism for selecting the magnification, an eyepiece, a mount for attaching a camera, an illuminator and two linear polarizers, where the two linear polarizers are attached, one at a point along the optical path of the illuminating light beam and the other at a point along the optical path of the rays that form the image of the tissue, with the capability of rotating the polarization planes of these light polarizing optical elements, so that when these planes are perpendicular to each other, the contribution of the tissue's surface reflection to the formed image is eliminated. In another embodiment, in the case of endoscopy, the endoscope may comprise optical means for transferring light from the light source onto the tissue surface and for collecting and transferring along almost the same axis and focusing the rays that form the image of the tissue, and two linear polarizers, where the two linear polarizers are attached, one at a point along the optical path of the illuminating light beam and the other at a point along the optical path of the rays that form the image of the tissue, with the capability of rotating the polarization planes of these light polarizing optical elements, so that when these planes are perpendicular to each other, the contribution of the tissue's surface reflection to the formed by the endoscope image is eliminated. In another embodiment, in the case of microscopes used in clinical diagnostic examinations, surgical microscopes and colposcopes, may additionally comprise a reflective objective lens, where the reflective objective replaces the refractive one, which reflective objective is devised so that in the central part of its optical front aperture the second reflection mirror is located, and in the rear part (non-reflective) of this mirror, illumination means are attached from which light is emitted toward the object, so that with or without illumination beam zooming and focusing optics the central ray of the emitted light cone is coaxial, with the central ray of the light beam that enters the imaging lens, and with the aid of zooming and focusing optics of illumination beam that may be adjusted simultaneously and automatically with the mechanism for varying the magnification of the optical imaging system, the illuminated area and the field-of-view of the imaging system, are varying simultaneously and proportionally, so that any decrease in image brightness caused by increasing the magnification, is compensated with the simultaneous zooming and focusing of the illumination beam. Other features and advantages of the invention will be apparent from the following detailed description and claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of the present method's basic principle. FIG. 2 , illustrates an embodiment of the invention comprising a method for capturing in two spectral bands simultaneously and in any spatial point of the area under analysis, the kinetics of the alterations in the characteristics of the remitted from the tissue light, before and the after the administration of the contrast enhancing agent FIG. 3 illustrates another embodiment of the invention comprising a method for capturing in different spectral bands simultaneously and in any spatial point of the area under analysis, the kinetics of the alterations in the characteristics of the remitted from the tissue light, before and the after the administration of the contrast enhancing agent. FIG. 4 illustrates a schematic diagram of a medical microscope comprising a light source (LS), a magnification selection mechanism (MS), an eyepiece (EP) and a mount for attaching the image capturing module (CA), (detector(s), readout electronics etc). FIG. 5 illustrates an endoscope comprising an eyepiece (EP), which can be adapted to an electronic imaging system, optical fibers or crystals for the transmission of both illumination and image rays, optics for the linear polarization of light, one interposed to the optical path of the illumination rays (LE) and one to the path of the ray that form the optical image of the tissue (II). FIG. 6 depicts a colposcopic apparatus comprising an articulated arm (AA), onto which the optical head (OH) is affixed, which includes a light source (LS), an objective lens (OBJ), an eye-piece (EP) and optics for selecting the magnification (MS). FIG. 7 illustrates an optical imaging apparatus which comprises a light source located at the central part of its front-aperture. DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a method and system for the in-vivo, non-invasive detection and mapping of the biochemical and or functional alterations of tissue, e.g., tissue within a subject. Upon selection of the appropriate agent which enhances the optical contrast between normal and pathologic tissue (depending on the tissue's pathology), this agent is administered, e.g., topically to the tissue. In FIG. 1 , the tissue (T), is sprayed using an atomizer (A), which contains the agent, e.g., acetic acid. At the same time, the tissue is illuminated with a source that emits light at a specific spectral band, depending on the optical characteristics of both the agent and the tissue. Illumination and selection of the spectral characteristics of the incident to the tissue light can be performed with the aid of a light source (LS) and a mechanism for selecting optical filters (OFS). Of course there are several other methods for illuminating the tissue and for selecting the spectral characteristics of the incident light (e.g., Light emission diodes, LASERS and the like). For the imaging of the area of interest, light collection optics (L) are used, which focus the image onto a two-dimensional optical detector (D). The output signal of the latter is amplified, modulated and digitized with the aid of appropriate electronics (EIS) and finally the image is displayed on a monitor (M) and stored in the data-storing means of a personal computer (PC). Between tissue (T) and detector (D), optical filters (OFI) can be interposed. The interposition of the filter can be performed for tissue (T) imaging in selected spectral bands, at which the maximum contrast is obtained between areas that are subjected to different grade of alterations in their optical characteristics, provoked after administering the appropriate agent. Before administration of the latter, images can be captured and used as reference. After the agent has been administered, the detector (D), captures images of the tissue, in successive time instances, which are then stored in the computer's data-storage means. The capturing rate is proportional to the rate at which the tissue's optical characteristics are altered, following the administration of the agent. In FIG. 1 , images of the same tissue area are schematically illustrated, which have been stored successively before and after administering the agent (STI). In these images, the black areas represent tissue areas that do not alter their optical characteristics (NAT), while the gray-white tones represent areas which alter their optical characteristics (AT), following the administration of the agent. The simultaneous capture of the intensity of the light re-emitted from every spatial point of the tissue area under analysis and in predetermined time instances, allows the calculation of the kinetics of the provoked alterations. In FIG. 1 , two curves are illustrated: pixel value in position xy (Pvxy), versus time t. The curve ATC corresponds to an area where agent administration provoked alterations (AT) in the tissue's optical characteristics. The curve (NATC) corresponds to an area where no alteration took place (NAT). The mathematical analysis of these curves leads to the calculation of quantitative parameters for every pixel. One example of a quantitative parameter is the value PV xy (t i ), which corresponds to the pixel value at point (x,y) at any point in time (t i ). Another example of a quantitative parameter is the relaxation time t rel , which corresponds to the time when the pixel value at point (x,y) (i.e., PV xy ) attains the value of A/e, where A is the maximum pixel value of the PV xy versus time (t) curve, and the base of Neper logarithms is represented by e. The calculation of these parameters (P) in every spatial point of the area under analysis, allows the calculation of the image or images of the kinetics of the phenomenon (KI), with pixel values that are correlated with these parameters. These values can be represented with a scale of pseudocolors (Pmin, Pmax), the spatial distribution of which allows for immediate optical evaluation of the intensity and extent of the provoked alterations. Depending on the correlation degree between the intensity and the extent of the provoked alterations with the pathology and the stage of the tissue lesion, the measured quantitative data and the derived parameters would allow the mapping, the characterization and the border-lining of the lesion. The pseudocolor image of the phenomenon's kinetics (KI), which expresses the spatial distribution of one or more parameters, can be overimposed (after being calculated) on the tissue image, which is displayed in real-time on the monitor. The using the overimposed image as a guide, facilitates substantially the determination of the lesion's boundaries, for successful surgical removal of the entire lesion, or for locating suspicious areas in order to obtain a biopsy sample(s). Furthermore, based on the correlation of the phenomenon's kinetics with the pathology of the tissue, the measured quantitative data and the parameters that derive from them, can constitute quantitative clinical indices for the in vivo staging of the lesion or of sub-areas of the latter. In some cases it is necessary to capture the kinetics of the phenomenon in more than one spectral band. This can serve in the in vivo determination of illumination and/or imaging spectral bands at which the maximum diagnostic signal is obtained. Furthermore, the simultaneous imaging in more than one spectral bands can assist in minimizing the contribution of the unwanted endogenous scattering, fluorescence and reflection of the tissue, to the optical signal captured by the detector. The captured optical signal comprise the optical signal generated by the marker-tissue interaction and the light emitted from the endogenous components of the tissue. In many cases the recorded response of the components of the tissue constitute noise, since it occludes the generated optical signal, which caries the diagnostic information. Therefore, separation of these signals, based on their particular spectral characteristics, will result in the maximization of the signal-to-noise ratio and consequently in the improvement of the obtained diagnostic information. FIG. 2 , illustrates a method for capturing in two spectral bands simultaneously and in any spatial point of the area under analysis, the kinetics of the alterations in the characteristics of the remitted from the tissue light, before and the after the administration of the contrast enhancing agent. The remitted from the tissue light, is collected and focused by the optical imaging module (L) and passes through a beam splitting (BSP) optical element. Thus, two identical images of the tissue (T) are generated, which can be captured by two detectors (D 1 , D 2 ). In front of the detector, appropriate optical filters (Ofλ 1 ), (Ofλ 2 ) can be placed, so that images with different spectral characteristics are captured. Besides beam splitters, optical filters, dichroic mirrors etc, can also be used for splitting the image of the object. The detectors (D 1 ), (D 2 ) are synchronized so that they capture simultaneously the corresponding spectral images of the tissue (Tiλ 1 ), (Tiλ 2 ) and in successive time-intervals, which are stored in the computer's data storage means. Generalizing, multiple spectral images can be captured simultaneously by combining multiple splitting elements, filters and sources. FIG. 3 illustrates another method for capturing in different spectral bands simultaneously and in any spatial point of the area under analysis, the kinetics of the alterations in the characteristics of the remitted from the tissue light, before and the after the administration of the contrast enhancing agent. With the aid of a special prism (MIP) and imaging optics, it is possible to form multiple copies of the same image onto the surface of the same detector (D). Various optical filters (OFλ 1 ),(OFλ 2 ),(OFλ 3 ),(OFλ 4 ), can be interposed along the length of the optical path of the rays that form the copies of the object's image, so that the captured multiple images correspond to different spectral areas. For the clinical use of the methods of the invention, the different implementations of image capturing module described above can be integrated to conventional optical imaging diagnostic devises. Such devises are the various medical microscopes, colposcopes and endoscopes, which are routinely used for the in vivo diagnostic inspection of tissues. Imaging of internal tissues of the human body requires in most cases the illumination and imaging rays to travel along the same optical path, through the cavities of the body. Due to this fact, in the common optical diagnostic devises the tissue's surface reflection contributes substantially in the formed image. This limits the imaging information for the subsurface characteristics, which are in general of great diagnostic importance. This problem becomes more serious especially in epithelial tissues such as the cervix, larynx, oral cavity etc, which are covered by fluids such as mucus and saliva. Surface reflection also obstructs the detection and the measurement of the alterations in the tissue's optical properties, provoked after the administration of agents which enhance the optical contrast between normal and pathologic tissue. More specifically, when a special agent alters selectively the scattering characteristics of the pathologic tissue, the strong surface reflection that takes place in both pathologic (agent responsive) and normal (agent non responsive) tissue areas, occludes the diagnostic signal that originates from the interaction of the agent with the subsurface features of the tissue. In other words, surface reflection constitutes optical noise in the diagnostic signal degrading substantially the perceived contrast between agent responsive and agent non responsive tissue areas. Based on the above, the effective integration of the method to imaging diagnostic devises, requires embodiments of appropriate optics that ensure the elimination of the contribution of surface reflection to the captured image. FIG. 4 illustrates a schematic diagram of a medical microscope consisted from a light source (LS), a magnification selection mechanism (MS), an eyepiece (EP) and a mount for attaching the image capturing module (CA), (detector(s), readout electronics etc). For the elimination of the surface reflection a pair of linear polarizers is employed. The incident to the tissue light (LS), is linearly polarized by passing though a linear polarizer (LPO). The surface reflected light (TS), has the same polarization plane with the incident to the tissue light (Fresnel reflection). By interposing the other linear polarizer to the optical path of the rays that are remitted from the tissue and form the optical image of the object, with its polarization plane perpendicular to the polarization level of the incident to the tissue light (IPO), the contribution of the surface reflection to the image of the object is eliminated. The light which is not surface-reflected enters the tissue, where due to multiple scattering, light polarization is randomized. Thus, a portion of the re-emitted light passes through the imaging polarization optics, carrying improved information for the subsurface features. FIG. 5 illustrates an endoscope consisted of an eyepiece (EP), which can be adapted to an electronic imaging system, optical fibers or crystals for the transmission of both illumination and image rays, optics for the linear polarization of light, one interposed to the optical path of the illumination rays (LE) and one to the path of the ray that form the optical image of the tissue (II). The polarization plane of the polarizing optics, which are adapted to the exit of light from the endoscope (LPO), is perpendicular to the polarization plane of the polarizer, which is adapted to the point where the light enters the endoscope (IL). The polarization optics of the incident to the tissue light could also be adapted at the point where the light enters the endoscope (IL) but in this case, the endoscope has to be constructed using polarization preserving crystals or fiber optics for transferring the light. If polarization preserving light transmission media are used, then the polarizing optics of the imaging rays can be interposed in their path and before or after the eyepiece (EP). A problem for the effective clinical implementation of the described method herein is the micro-movements of the patient, which are always present during the snapshot imaging of the same tissue area. Obviously this problem is eliminated in case that the patient is under anesthesia (open surgery). In most cases however the movements of the tissue relative to the image capturing module, occurring during the successive image capturing time-course, have the consequence that the image pixels, with the same image coordinates, do not correspond to exactly the same spatial point x,y of the tissue area under examination. This problem is typically encountered in colposcopy. A method to eliminate the influence to the measured temporal data of the relative movements between tissue and image capturing module is presented below. A colposcopic apparatus is illustrated in FIG. 6 , consisted of an articulated arm (AA), onto which the optical head (OH) is affixed, which includes a light source (LS), an objective lens (OBJ), an eye-piece (EP) and optics for selecting the magnification (MS). The image capturing module is attached to the optical head (OH), through an opto-mechanical adapter. A speculum (KD), which is used to open-up the vaginal canal for the visualization of the cervix, is connected mechanically with the optical head (OH), so that the its longitudinal symmetry axis (LA), to be perpendicular to the central area of the objective lens (OBJ). The speculum enters the vagina and its blades are opened up compressing the side walls of the vagina. The Speculum (KD), been mechanically connected with the optical head (OH), transfer any micromovement of the patient to the optical head (OH), which been mounted on an articulated arm (AA), follows these movements. Thus the relative position between tissue and optical head remains almost constant. An important issue that must also be addressed for the successful clinical implementation of the diagnostic method described herein, is the synchronization of the application of the contrast enhancing agent with the initiation of the snapshot imaging procedure. FIG. 6 , illustrates an atomizer (A) attached to the optical head of the microscope. The unit (MIC) is comprised of electronics for controlling the agent sprayer and it can incorporate also the container for storing the agent. When the unit (MIC) receives the proper command from the computer it sprays a predetermined amount of the agent onto the tissue surface, while the same or another command initiates the snapshot image capturing procedure. The diagnostic examination of non-directly accessible tissues, located in cavities of the human body (ear, cervix, oral cavity, esophagus, colon, stomach), is performed with the aid of common clinical microscopes. In these devises the illumination-imaging rays are near co-axial. More specifically, the line perpendicular to the exit point of light into the air, and the line perpendicular to the objective lens, form an angle of a few degrees. Due to this fact, these microscopes operate at a specific distance from the subject (working distance), in which the illuminated tissue area, coincides with the field-of-view of the imaging system. These microscopes are found to be inappropriate in cases where tissue imaging through human body cavities of small diameter and at short working distances, is required. These technical limitations are also constituting serious restricting factors for the successful clinical implementation of the method described herein. As it has been discussed above, elimination of surface reflection results in a substantial improvement of the diagnostic information, obtained from the quantitative assessment of marker-tissue interaction kinetics. If a common clinical microscope is employed as the optical imaging module, then due the above mentioned Illumination-imaging geometry, multiple reflections are occurring in the walls of the cavity, before the light reaches the tissue under analysis. In the case of colposcopy, multiple reflections are much more intense, since they are mainly taking place onto highly reflective blades of the speculum. Recall that the latter is inserted into the vagina to facilitate the inspection of cervix. If the illuminator of the imaging apparatus emits linearly polarized light, the multiple reflections are randomizing the polarization plane of the incident light. And as it has been discussed above, if the incident to the tissue under analysis light is not linearly polarized, then the elimination of the contribution of the surface reflection to the captured image can not be effective. FIG. 7 illustrates an optical imaging apparatus which comprises a light source located at the central part of its front-aperture. With this arrangement, the central ray of the emitted light cone is coaxial, with the central ray of the light beam that enters the imaging apparatus. This enables illumination rays to reach directly the tissue surface under examination and not after multiple reflections in the wall of the cavity. A reflective-objective lens is used, consisted at least of a first reflection (1RM) and a second reflection (2RM) mirror, where at the rear part of the first reflection mirror (2RM), a light source (LS) is attached together (if required) with optics for light beam manipulation such as zooming and focusing (SO). The reflective objective lens (RO), by replacing the common refractive-objective, which is used in conventional microscopes, provides imaging capability in cavities of small diameter, with freedom in choosing the working distance. The zooming and focusing optics of the light beam can be adjusted simultaneously with the mechanism for varying the magnification of the optical imaging system, so that the illumination area and the field-of-view of the imaging system, are varying simultaneously and proportionally. This has as a result, the preservation of image brightness regardless of the magnification level of the lens. The imaging-illumination geometry embodied in this optical imaging apparatus among with the light beam manipulation options, enable the efficient elimination of the contribution of the surface reflection to the captured image and consequently the efficient clinical implementation of the method described herein. EQUIVALENTS Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.

The present invention provides a method and an apparatus for the in vivo, non-invasive, early detection of alterations and mapping of the grade of these alterations, caused in the biochemical and/or in the functional characteristics of epithelial tissues during the development of tissue atypias, dysplasias, neoplasias and cancers. The method is based, at least in part, on the simultaneous measurement of the spatial, temporal and spectral alterations in the characteristics of the light that is re-emitted from the tissue under examination, as a result of a combined tissue excitation with light and special chemical agents. The topical or systematic administration of these agents result in an evanescent contrast enhancement between normal and abnormal areas of tissue. The apparatus enables the capturing of temporally successive imaging in one or more spectral bands simultaneously. Based on the measured data, the characteristic curves that express the agent-tissue interaction kinetics, as well as numerical parameters derived from these data, are determined in any spatial point of the examined area. Mapping and characterization of the lesion, are based on these parameters.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. application Ser. No. 13/792,566, filed on Mar. 11, 2013, the content of which is relied upon and incorporated herein by reference in its entirety, and the benefit of priority under 35 U.S.C. §120 is hereby claimed; this application also claims priority to U.S. Provisional Patent Application Ser. No. 61/635,600 filed on Apr. 19, 2012, the content of which is relied upon and incorporated herein by reference in its entirety, and the benefit of priority under 35 U.S.C. §119(e) is hereby claimed. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to electrical wiring devices, and particularly to power control wiring devices such as dimmer and fan speed control devices. [0004] 2. Technical Background [0005] In most residences, a simple ON/OFF switch may be the primary way people control the home's lighting fixtures or air-circulating fan fixtures. One obvious drawback to using simple ON/OFF switches to control these devices is experienced by the homeowner when he pays the electrical bill—a given light (or fan) is either ON or OFF—a simple switch is thus unable to vary the amount of light (and hence control the amount of power consumed). Stated differently, by controlling light intensity or fan speed in accordance with needed or desired parameters, electricity usage is reduced, saving money and natural resources. In accordance with the present invention, therefore, a power control device refers to an electrical control device that may be employed to adjust the amount of current delivered to any variable electrical load, such as a light or a motor. [0006] When the electric load is a lighting device, the power control device is commonly referred to as a dimmer. For example, when a light is dimmed 25% by a dimmer, a 20% reduction in the amount of electricity required to operate the lamp is realized. When a light is dimmed by 50%, a 40% electricity reduction is realized. Second, a dimmer greatly extends lamp life because it reduces the strain on the filament. When a light is dimmed 25%, a given lamp lasts four (4) times longer than it would at full power. When the light is dimmed by 50%, it can last as much as 20 times longer (than a light that is continuously operated at full power). If the power control device is configured to control a motor, such as a fan motor, the power control device is referred to as a motor speed controller. Motor speed controllers are also used to control the speed of machinery such as power tools, electric drills, chair lifts, stationary machinery, and other such variable speed motor driven elements. [0007] Power control devices are typically packaged in a wiring device form factor for installation in a wall outlet box. The wiring device may include one or more power control devices within the device housing. For example, wiring devices that are equipped with both fan motor control and lighting control features are ubiquitous. The exterior of the wiring device includes either screw terminals or wire terminals for subsequent connection between the AC power source and the load. The conventional wiring device form factor also provides a user accessible interface that includes one or more switch mechanisms such as buttons, levers, dials, slide switches, and other such input control mechanisms that permit a user to vary the power to a load or turn it ON/OFF. [0008] Prior to device installation, wiring from the AC power source and wiring to the load(s) are disposed inside the outlet box. The outlet box is usually located proximate to the load being controlled. The device is installed by connecting the wiring inside the outlet box to the appropriate wiring device terminals disposed on the exterior of the wiring device. The power control wiring device is then inserted into the outlet box and attached to the outlet box using one or more fasteners. A cover plate is installed to complete the installation. One of the drawbacks associated with older conventional power control devices relates to the fact that many of these devices were often installed without a neutral wire being routed into the device box. What is needed therefore is a power control device that can be employed in any structure being retrofitted or remodeled. Stated differently, a power control device is needed that can work with existing wiring configurations (whether the device box includes a neutral wire or does not include a neutral wire). [0009] Often, a residence includes a three way lighting arrangement whereby one light fixture may be operated by two separate three-way switches. Often, one three-way switch is installed at an upstream location while a second three-way switch is installed at a downstream location. This allows a resident to conveniently turn the lights ON or OFF from two different locations. Unfortunately, this may lead to difficulties when a structure or space is being retrofitted, since certain conventional dimmers may only be installed at one of the three way switch locations. This requires the homeowner to know how the existing wiring is disposed in the room (behind the plaster or sheet rock). What is needed therefore is a dimmer that can be installed at any of the three-way switch locations. [0010] Turning now to so-called “green” issues, the public has developed an increased awareness of the impact that energy generation has on the environment. Moreover, as the economies of countries such as Brazil, India, China, etc. improve and develop their need for energy resources increases accordingly. As such, the global demand for energy has risen sharply, while the supply of planet earth's resources remains fixed. In light of the pressures of supply and demand, the cost of energy resources will only increase. There is thus a need to use limited energy resources more wisely and more efficiently. More efficient light sources and electrical fixtures have been developed to replace the conventional incandescent lighting devices in response to this need. For example, compact fluorescent lights (CFL) and light emitting diode (LED) devices are far more efficient than conventional incandescent lights and thus provide homeowners/tenants with an acceptable level of service while using less energy and incurring lower costs. [0011] One of the drawbacks of conventional dimmer devices relates to the fact that incandescent lights, fluorescent lights, MLV lighting, ELV lighting, CFL devices and LED lighting may have different electrical operating characteristics. Dimmers have a solid state switching component that turns the lamp on during a user adjustable portion of each line frequency cycle and turns the lamp off during the remaining portion of the cycle. Dimmers that turn the load ON at a zero crossing of the line frequency and OFF at a subsequent phase angle are referred to as “reverse phase” dimmers. Dimmers that turn the load ON at selected phase angle and turn the load OFF at the following zero cross are known as “forward phase” dimmers. Each type of load will be less susceptible to unwanted effects (such as flickering) when it is properly matched to an appropriate dimmer. Moreover, the life expectancy of the both the dimmer and the load may be adversely affected if the dimmer and the load are not properly matched. When a user installs a light source (load) that is not matched to the corresponding dimmer, the light will not operate properly and the user will either have to change the light source or the dimmer to rectify the situation. [0012] Accordingly, a need exists for a power control device that can drive electrical loads over a wide range of wattages. A need also exists for an intelligent dimmer that is capable of recognizing the type of load it is driving, and adjust the drive signal to match the operating parameters of the load. For example, an intelligent dimmer is needed that can automatically calibrate the dimmer based on the load current demands of a particular electrical load. The intelligent dimmer should also be able to adaptively limit in-rush currents that are known to shorten the life expectancy of the solid state switching components used in dimmer products. SUMMARY OF THE INVENTION [0013] The present invention addresses the needs described above by providing an intelligent dimmer that can be employed in any structure being retrofitted or remodeled. The present invention may be installed in existing wiring, i.e., whether the neutral is present or not present in the device box. The intelligent dimmer of the present invention may also be installed at either three-way switch location in a retrofit without regard to how the electrical wiring is disposed in the existing structure. The present invention is directed to an intelligent dimmer that is capable of recognizing the type of load it is controlling, and adjust the drive signal to match the operating parameters of the load. The present invention can adaptively drive electrical loads over a wide range of wattages. The intelligent dimmer of the present invention is configured to automatically calibrate itself based on the load current demands of a particular electrical load. The intelligent dimmer of the present invention also adaptively limits in-rush currents to extend the life expectancy of the solid state switching components used therein. [0014] One aspect of the present invention is an electrical wiring device that includes a housing assembly having a plurality of terminals at least partially disposed therein, the plurality of terminals being configured to be coupled to an AC power source and at least one electrical load. A sensor element is coupled to the plurality of terminals and configured to provide a sensor signal based on at least one load power parameter of the at least one electrical load. At least one variable control mechanism is coupled to the housing assembly, the at least one variable control mechanism being configured to adjustably select a user adjustable load setting, the user adjustable load setting being adjustable between a minimum setting and a maximum setting. At least one series pass element is coupled between the AC power source and at least one electrical load, the at least one series pass element being configured to provide output power to the at least one electrical load in accordance with the user load setting, the output power being less than or equal to the AC power. A regulation circuit is coupled to the sensor element and the at least one series pass element, the regulation circuit being configured to enter a calibration mode when AC power is applied to at least a portion of the plurality of terminals, in the calibration mode the regulation circuit being configured to provide the at least one series pass element with an initial output power setting while monitoring the at least one load power parameter, the regulation circuit being further configured to increment the initial output power setting to at least one incremental output power setting while monitoring the at least one load power parameter, the regulation circuit being configured to identify a load type of the at least one electrical load based on the at least one incremental output power setting and the at least one load power parameter that results in the at least one electrical load being energized, the regulation circuit selecting calibration values based on the load type, the selected calibration values corresponding to the minimum setting and the maximum setting. [0015] In one embodiment, the plurality of terminals includes a neutral terminal or a ground terminal. [0016] In one embodiment, the identified load type determines if the at least one electrical load operates in a forward phase control mode or a reverse phase control mode. [0017] In one embodiment, the regulation circuit includes a microcontroller coupled to a memory, the memory being configured to store a plurality of characteristic load curves stored therein, the plurality of characteristic load curves including a plurality of incremental power settings and a plurality of load power parameters, each characteristic load curve of the plurality of characteristic load curves correlating each load type with a predetermined incremental output power setting versus a predetermined load power parameter. [0018] In one version of the embodiment, the predetermined load power parameter includes an inrush current parameter. [0019] In one embodiment, a power supply coupled to the AC power source, the power supply being configured to provide at least one supply voltage. [0020] In one version of the embodiment, the power supply is a half wave power supply that is selectively coupled to the AC power source via one of three diodes, and wherein the plurality of terminals includes a phase terminal, a first traveler terminal and a second traveler terminal, the power supply being individually coupled to phase terminal, a first traveler terminal and a second traveler terminal by corresponding diodes of the three diodes. [0021] In one embodiment, the regulation circuit includes a zero cross circuit coupled to the AC power source via one of three electrical paths, each of the three electrical paths including a diode. [0022] In one version of the embodiment, each of the three electrical paths are coupled to one of a first traveler terminal, a second traveler terminal or a phase terminal. [0023] In one embodiment, the regulation circuit is configured to enter the calibration mode when at least a portion of the at least one variable control mechanism is actuated. [0024] In one version of the embodiment, the portion includes an ON/OFF control. [0025] In one embodiment, the sensor element is a current sensor configured to sense current propagating through the at least one electrical load. [0026] In one embodiment, the at least one electrical load is selected from a group of electrical loads including a variable speed motor, an incandescent lighting load, a magnetic low voltage (MLV) load, a fluorescent lighting load, an electronic ballast (EFL) type lighting load, a halogen light load, an electronic low voltage (ELV) load, and a compact florescent light (CFL) load. [0027] In one embodiment, the series pass element is selected from a group of series pass elements including a thyristor device, a triac device, and at least one transistor device. [0028] In one version of the embodiment, the at least one transistor device includes a first MOSFET transistor coupled to a second MOSFET transistor, the first MOSFET transistor being configured to provide the output power in a first half cycle of the AC power source and the second MOSFET transistor being configured to provide the output power in a second half cycle of the AC power source. [0029] In another aspect, the present invention includes an electrical wiring device that includes a housing assembly having a plurality of terminals at least partially disposed therein, the plurality of terminals being configured to be coupled to an AC power source and at least one electrical load. A sensor element is coupled to the plurality of terminals and configured to provide a sensor signal based on at least one load power parameter of the at least one electrical load. At least one variable control mechanism is coupled to the housing assembly, the at least one variable control mechanism being configured to adjustably select a user adjustable load setting, the user adjustable load setting being adjustable between a minimum setting and a maximum setting. At least one series pass element is coupled between the AC power source and at least one electrical load, the at least one series pass element being configured to provide output power to the at least one electrical load in accordance with the user load setting, the output power being less than or equal to the AC power. A regulation circuit is coupled to the sensor element and the at least one series pass element, the regulation circuit being configured to enter a calibration mode when AC power is applied to at least a portion of the plurality of terminals. In the calibration mode the regulation circuit is configured to provide the at least one series pass element with an initial output power setting while monitoring the at least one load power parameter, the regulation circuit being further configured to increment the initial output power setting to at least one incremental output power setting while monitoring the at least one load power parameter, the regulation circuit being configured to select a forward phase control mode or a reverse phase control mode based on the at least one incremental output power setting or the at least one load power parameter that results in the at least one electrical load being energized. [0030] In one embodiment, the regulation circuit selects calibration values based on which of the forward phase control mode or the reverse phase control mode is selected, the selected calibration values corresponding to the minimum setting and the maximum setting. [0031] In one embodiment, the regulation circuit is configured to identify a load type of the at least one electrical load based on the at least one incremental output power setting and the at least one load power parameter that results in the at least one electrical load being energized, the regulation circuit selecting calibration values based on the load type, the selected calibration values corresponding to the minimum setting and the maximum setting. [0032] In one embodiment, the plurality of terminals includes a neutral terminal or a ground terminal. [0033] In one embodiment, the regulation circuit includes a microcontroller coupled to a memory, the memory being configured to store a plurality of characteristic load curves stored therein, the plurality of characteristic load curves including a plurality of incremental power settings and a plurality of load power parameters, each characteristic load curve of the plurality of characteristic load curves correlating each load type with a predetermined incremental output power setting versus a predetermined load power parameter. [0034] In one embodiment, a power supply is coupled to the AC power source, the power supply being configured to provide at least one supply voltage. [0035] In one version of the embodiment, the power supply is a half wave power supply that is selectively coupled to the AC power source via one of three diodes, and wherein the plurality of terminals includes a phase terminal, a first traveler terminal and a second traveler terminal, the power supply being individually coupled to phase terminal, a first traveler terminal and a second traveler terminal by corresponding diodes of the three diodes. [0036] In one embodiment, the regulation circuit includes a zero cross circuit coupled to the AC power source via one of three electrical paths, each of the three electrical paths are selectively coupled to one of a first traveler terminal, a second traveler terminal or a phase terminal via a diode. [0037] In one embodiment, the regulation circuit is configured to enter the calibration mode when at least a portion of the at least one variable control mechanism is actuated, the portion including an ON/OFF control. [0038] In one embodiment, the sensor element is a current sensor configured to sense current propagating through the at least one electrical load. [0039] In one embodiment, the at least one electrical load is selected from a group of electrical loads including a variable speed motor, an incandescent lighting load, a magnetic low voltage (MLV) load, a fluorescent lighting load, an electronic ballast (EFL) type lighting load, a halogen light load, an electronic low voltage (ELV) load, and a compact florescent light (CFL) load. [0040] In one embodiment, at least one load power parameter is based on a current propagating through the at least one electrical load. [0041] In one embodiment, the series pass element is selected from a group of series pass elements including a thyristor device, a triac device, and at least one transistor device. [0042] In one version of the embodiment, the at least one transistor device includes a first MOSFET transistor coupled to a second MOSFET transistor, the first MOSFET transistor being configured to provide the output power in a first half cycle of the AC power source and the second MOSFET transistor being configured to provide the output power in a second half cycle of the AC power source. [0043] In another aspect, the present invention includes a method for controlling an electrical wiring device, the method includes the steps of: providing a housing assembly having a plurality of terminals at least partially disposed therein, the plurality of terminals being configured to be coupled to an AC power source and at least one electrical load, the housing also including at least one variable control mechanism coupled to the housing assembly, the at least one variable control mechanism being configured to adjustably select a user adjustable load setting, the user adjustable load setting being adjustable between a minimum setting and a maximum setting, the housing further including at least one series pass element coupled between the AC power source and at least one electrical load, the at least one series pass element being configured to provide output power to the at least one electrical load in accordance with the user load setting, the output power being less than or equal to the AC power; entering a calibration mode when AC power is applied to at least a portion of the plurality of terminals; providing the at least one series pass element with an initial output power setting while monitoring at least one load power parameter; incrementing the initial output power setting to at least one incremental output power setting while monitoring the at least one load power parameter; and selecting a forward phase control mode or a reverse phase control mode based on the at least one incremental output power setting or the at least one load power parameter that results in the at least one electrical load being energized. [0044] In one embodiment, the method includes selecting the calibration values based on which of the forward phase control mode or the reverse phase control mode is selected, the selected calibration values corresponding to the minimum setting and the maximum setting. [0045] In one embodiment, the method includes identifying a load type of the at least one electrical load based on the at least one incremental output power setting and the at least one load power parameter that results in the at least one electrical load being energized, [0046] In one embodiment, the method includes selecting calibration values based on the load type, the selected calibration values corresponding to the minimum setting and the maximum setting. [0047] In one embodiment, the plurality of terminals includes a neutral terminal or a ground terminal. [0048] In one embodiment, the step of providing includes providing a microcontroller coupled to a memory, the memory being configured to store a plurality of characteristic load curves stored therein, the plurality of characteristic load curves including a plurality of incremental power settings and a plurality of load power parameters, each characteristic load curve of the plurality of characteristic load curves correlating each load type with a predetermined incremental output power setting versus a predetermined load power parameter. [0049] In one embodiment, the step of providing includes providing a power supply coupled to the AC power source, the power supply being configured to provide at least one supply voltage. [0050] In one version of the embodiment, the power supply is a half wave power supply that is selectively coupled to the AC power source via one of three diodes, and wherein the plurality of terminals includes a phase terminal, a first traveler terminal and a second traveler terminal, the power supply being individually coupled to phase terminal, a first traveler terminal and a second traveler terminal by corresponding diodes of the three diodes. [0051] In one embodiment, the step of providing includes providing a zero cross circuit coupled to the AC power source via one of three electrical paths, each of the three electrical paths are selectively coupled to one of a first traveler terminal, a second traveler terminal or a phase terminal via a diode. [0052] In one embodiment, the method includes entering a calibration mode when at least a portion of the at least one variable control mechanism is actuated, the portion including an ON/OFF control. [0053] In one embodiment, the series pass element is selected from a group of series pass elements including a thyristor device, a triac device, and at least one transistor device. [0054] In one version of the embodiment, the at least one transistor device includes a first MOSFET transistor coupled to a second MOSFET transistor, the first MOSFET transistor being configured to provide the output power in a first half cycle of the AC power source and the second MOSFET transistor being configured to provide the output power in a second half cycle of the AC power source. [0055] Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings. [0056] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein. [0057] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the invention and together with the description serve to explain the principles and operation of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0058] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. [0059] FIG. 1 is a general block diagram of a universal power control device in accordance with the present invention; [0060] FIG. 2A-2B are block diagrams of the universal power control device in accordance with the first embodiment, FIG. 2A is a block diagram of the AC power circuitry and FIG. 2B is a block diagram of the processing and logic circuitry; [0061] FIG. 3 is a detailed circuit diagram of a microcontroller circuit in accordance with the first embodiment of the present invention; [0062] FIG. 4 is a detailed circuit diagram of a user display circuit in accordance with an embodiment of the present invention; [0063] FIG. 5 is a detailed circuit diagram of a power supply in accordance with an embodiment of the present invention; [0064] FIG. 6 is a detailed circuit diagram of a dimmer circuit in accordance with an embodiment of the present invention; [0065] FIG. 7 is a detailed circuit diagram of a switch relay circuit in accordance with an embodiment of the present invention; [0066] FIG. 8 is a diagrammatic depiction of a load sensor in accordance with an embodiment of the present invention; [0067] FIG. 9 is a detailed circuit diagram of a load sensor detector circuit in accordance with an embodiment of the present invention; [0068] FIGS. 10A , 10 B, 10 C are diagrammatic depictions of a three-way switch arrangement in accordance with the present invention; [0069] FIG. 11 is a block diagram of the AC power circuitry in accordance with an embodiment of the present invention; [0070] FIG. 12 is a detailed circuit diagram of a power supply in accordance with an embodiment of the present invention; [0071] FIG. 13 is a detailed circuit diagram of a dimmer circuit in accordance with an embodiment of the present invention; [0072] FIG. 14 is a detailed circuit diagram of a switch relay in accordance with an embodiment of the present invention; [0073] FIGS. 15A-15B are diagrammatic depictions of another three-way switch arrangement in accordance with the present invention; [0074] FIG. 16 is a flow chart diagram illustrating a software auto-calibration sequence in accordance with the present invention; [0075] FIG. 17 is a flow chart diagram illustrating a software main program in accordance with the present invention; [0076] FIG. 18 is a flow chart diagram illustrating a software zero cross interrupt routine in accordance with the present invention; [0077] FIG. 19 is a flow chart diagram illustrating a software load timer interrupt routine in accordance with the present invention; [0078] FIG. 20 is a front isometric view of a power control device in accordance with an embodiment of the present invention; [0079] FIG. 21 is a rear isometric view of the power control device depicted in FIG. 20 ; [0080] FIG. 22 is a rear isometric view of the heat sink assembly of the power control device depicted in FIG. 20 ; [0081] FIG. 23 is a rear isometric view of the heat sink assembly and the power handling printed circuit board of the power control device depicted in FIG. 20 ; [0082] FIG. 24 is a front isometric view of FIG. 20 with the ON/OFF actuator cover removed; [0083] FIG. 25 is a front isometric view of FIG. 20 with the ON/OFF actuator cover and the dimmer cover removed; [0084] FIG. 26 is a front isometric view of the heat sink assembly of FIG. 22 disposed within the back body member; [0085] FIG. 27 is a front isometric view of the power handling printed circuit board of FIG. 23 disposed within the back body member of the device of FIG. 20 ; [0086] FIG. 28 is an exploded view of the power control device depicted in FIG. 20 ; [0087] FIG. 29 is an isometric view of the ON/OFF actuator cover depicted in FIG. 20 ; [0088] FIGS. 30-31 are detailed isometric views of the dimmer actuator cover depicted in FIG. 20 ; and [0089] FIG. 32 is a cross-sectional view of the power control device depicted in FIG. 20 . DETAILED DESCRIPTION [0090] Reference will now be made in detail to the present exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. An exemplary embodiment of the universal power control device of the present invention is shown in FIG. 1 , and is designated generally throughout by reference numeral 10 . [0091] As embodied herein, and depicted in FIG. 1 , a general block diagram of a universal power control device 10 in accordance with the present invention is disclosed. The device 10 includes a power handling printed circuit board (PCB) 10 - 1 and a processing or logic printed circuit board 10 - 2 . The power handling PCB 10 - 1 is coupled to the logic PCB 10 - 2 by an interface 10 - 3 . In another embodiment of the present invention, these circuits are disposed on a single printed circuit board (PCB). In yet another embodiment, for example, the power handling circuitry 10 - 1 is disposed on a printed circuit board adjacent a heat sink (not shown) whereas the logic circuitry 10 - 2 is disposed on a second PCB disposed adjacent to a cover portion. [0092] The power handling circuit 10 - 1 is coupled to AC power by way of the external AC terminals 12 . If the device is employed as a single pole single throw (SPST) switch, the power control device is coupled to the hot connector (black) and inserted between the AC power source and the load to provide the load with variable power (e.g., dimmed power in a lighting application). The power control device 10 may also be employed in three-way switching arrangements. In this case, the device 10 provides terminal connections for a hot (or load) wire, a first traveler wire and a second traveler wire. In many retrofits, the device box may not have a neutral wire; in newer construction, or in newer retrofits, the device box may include a neutral wire. The present invention can accommodate a neutral wire and may also include a ground wire in at least one embodiment. [0093] The power supply 20 is configured to rectify the AC power derived from terminals 12 to provide a high voltage DC supply for the relay circuit 40 and a +5 VDC supply for use by the logic circuitry 10 - 2 . The power supply 20 further provides a zero-cross signal which is used by the processing circuitry 110 for timing purposes. The power handling circuit 10 - 1 also includes a load sensor 50 that is configured to provide the processing circuitry 110 with load current data. In one embodiment described below, the processing circuit 110 is configured to determine the type of lighting device that is installed by monitoring the load current data to determine whether the device 10 should operate using forward phase control or reverse phase control. Similarly, the processing circuit 110 also monitors the load current data to determine an optimal dimming voltage range for the specific lighting device type. In another embodiment described below, the processor can determine the dimming voltage range by monitoring the supply voltage when a ground or neutral wire is present. In another embodiment, this dimming range data is provided by the user via inputs 120 disposed in the logic circuitry portion 10 - 2 of the device 10 . [0094] The user input circuitry 120 provides the processing circuitry 110 with information that includes, among other things, lighting device type, calibration commands, load ON/OFF commands, and dimmer setting inputs. The processing circuitry 110 is configured to actuate the relay circuit 40 to turn the load ON or OFF based on user commands. The processing circuit 110 also provides the dimmer circuit 30 with dimmer commands in accordance with the user inputs and the load sensor 50 input. The dimmer circuit, of course, provides a dimmed power signal to the load via the AC terminals 12 . As those skilled in the art will appreciate, dimming is accomplished in the reverse phase by switching the load current ON when the zero-crossing of the AC half-cycle is detected by the power detecting circuit 10 - 1 and turned OFF at a user adjustable phase angle. Conversely, in forward phase control, the load current is turned ON at the user adjustable phase angle and turned OFF when the next zero crossing is detected by the power detecting circuit. As those skilled in the art will appreciate, forward phase control is appropriate for conventional incandescent lighting, magnetic low voltage (MLV) lighting fixtures, conventional fluorescent lighting fixtures employing electronic ballasts (EFL), and halogen lighting. Reverse phase control is generally appropriate for electronic low voltage (ELV) lighting. Bulbs designed as higher efficiency 120V incandescent replacements, including LED bulbs and compact florescent lights (CFL) typically perform better with forward phase control. One of the universality features of the present invention is that the dimmer circuit may be employed in forward phase for certain optimized ELV, CFL and LED devices. [0095] It will be apparent to those of ordinary skill in the pertinent art that modifications and variations can be made to the processing circuitry 110 of the present invention depending on the degree of processing sophistication provided in a given device. The processing circuitry 110 may employ random access memory (RAM), read only memory (ROM), I/O circuitry, and communication interface circuitry coupled together by a bus system. The buss typically provides data, address, and control lines between a processor and the other system components. Moreover, processor functions may be implemented using hardware, software, general purpose processors, signal processors, RISC computers, application specific integrated circuits (ASICs), field programmable gate array (FPGA) devices, customized integrated circuits and/or a combination thereof. Thus, embodiments of the present invention are not limited to any specific combination of hardware circuitry and/or software. Taken together, RAM and ROM may be referred to herein as “computer-readable media.” The term “computer-readable medium,” as used herein, refers to any medium that participates in providing data and/or instructions to the processor for execution. For example, the computer-readable media employed herein may include any suitable memory device including SRAM, DRAM, NVRWM, PROM, E 2 PROM, Flash memory, or any suitable type of memory. In one embodiment, data and instructions may be provided to device 10 via electromagnetic waves. The processing circuitry 110 provides dimmer status information to the output display 130 such as the dimmable setting, lamp type, or user instruction. [0096] As embodied herein, and depicted in FIG. 2A , a block diagram of the AC power handling circuitry 10 - 1 in accordance with an embodiment of the present invention is disclosed. The terminals include a hot/load terminal 12 - 1 , traveler terminal 12 - 2 , traveler terminal 12 - 3 and neutral terminal 12 - 4 . The neutral terminal 12 - 4 is employed as a means for referencing ground. In another embodiment of the invention (not shown), the terminals include a ground terminal to which the ground conductor of the electrical distribution system is connected. The ground terminal is also used, of course, to reference ground potential. In another embodiment both a ground terminal and a neutral terminal are provided and the ground reference is associated with either terminal depending on whether the neutral conductor or ground conductor is provided by the electrical distribution system. In each of these embodiments, the device 10 also includes the traveler terminals ( 12 - 2 , 12 - 3 ) for use in three-way switch arrangements. The hot/load terminal 12 - 1 may be connected to the hot terminal of the AC power source, or to the load. This capability is a feature of the power supply circuit 20 and the dimmer circuit 30 described below. [0097] In one embodiment of the present invention, the interface device 10 - 3 is mounted on the power handling PCB 10 - 1 and is used to communicate power and logic signals between the PCB 10 - 1 and the PCB 10 - 2 . In addition, the power supply 20 provides +5 VDC and a reference ground connection via device 10 - 3 . The power supply 20 provides the processing circuitry 110 with the zero cross signal (ZC), and the load sensor 50 provides the processor circuitry with a sensor input (I sns) via an interface device 10 - 3 . The processing circuitry 110 provides the relay control signals (RC 1 , RC 2 ) and the dimmer control signal (PWM) via the interface 10 - 3 . [0098] As embodied herein, and depicted in FIG. 2B , a block diagram of the logic PCB 10 - 2 in accordance with one embodiment of the invention is disclosed. The logic PCB 10 - 2 includes interface pins 10 - 20 that mate with the interface device 10 - 3 ( FIG. 2A ) to complete the bi-directional communication path between the power PCB 10 - 1 and the logic PCB 10 - 2 . As noted above, power signals are conducted from the power handling circuit 10 - 1 to the logic circuit 10 - 2 , and the logic signals are conducted from logic circuit 10 - 2 to the power handling circuit 10 - 1 as appropriate. The load sensor detection circuit 112 employs the load sensor 50 signal (I Sns) to generate a sensor detection signal (I SNS AMP OUT) for use by the processor circuitry 110 . And as further shown in FIG. 2B , the processor circuit 110 provides the relay commands (RC 1 , RC 2 ) and the dimmer command (PWM) to the power circuit 10 - 1 via the interface pins 10 - 20 . The processor circuit 110 also provides output data to the display circuit 130 which is also disposed on the logic PCB 10 - 2 . Although they are not shown in FIG. 2B , the processor circuit 110 is also connected to user-accessible input devices that convert user commands into electronic commands. The user commands may be provided to the processor circuit by way of, but not limited to, switches, buttons, electromagnetic signals (e.g., RF or optical) that may originate from a keyboard, mouse, or by voice commands. [0099] As embodied herein and depicted in FIG. 3 , a detailed circuit diagram of a microcontroller circuit 110 - 1 in accordance with another embodiment of the present invention is disclosed. The processor circuit 110 is implemented using a microcomputer 110 - 1 which is selected based on a combination of characteristics including performance, cost, size and power consumption. In other words, the present invention contemplates a variety of models that provide the consumer with options that are closely suited to the consumers' needs and desires. The term “microcomputer performance” refers to an optimal combination of processing speed, memory size, I/O pin capability, and peripheral set capabilities (e.g., A/D converter, comparators, timers, serial bus, etc). As those skilled in the art will appreciate, any suitable processing device may be employed. In one embodiment of the present invention, the microcomputer is implemented by a device known as the “ATtiny44a”, which is manufactured by the Atmel Corporation. In another embodiment, the microcomputer is implemented using Atmel's “ATtiny84a” because the latter device offers more program memory than the former (i.e., 44a). Specifically, the ATtiny 84a includes 8 kB of program memory whereas the ATtiny 44a includes 4 kB of program memory. In one embodiment, the central processing unit (CPU) is operated at a clock frequency that is well below its rated frequency to thereby minimize power consumption. [0100] It will be apparent to those of skilled in the pertinent art that modifications and variations can be made to the processor circuit 110 of the present invention depending on the amount and sophistication of features that are provided to the user. As noted previously, any suitable arrangement of hardware and/or software may be employed given the size constraints of an electrical wiring device. Thus, processor circuit 110 may be implemented using general purpose processors, signal processors, RISC computers, application specific integrated circuits (ASICs), field programmable gate array (FPGA) devices, customized integrated circuits and/or a combination thereof. With respect to the microcomputer 110 - 1 depicted in FIG. 3 , any suitable microcomputer may be employed including, but not limited to those selected from the Microchip PIC12F family, the Freescale HC08 family, the Texas Instruments MSP430 family, or the ST Micro STM8 family (in addition to the Atmel devices described previously). [0101] Turning now to FIG. 3 in more detail, a description of the data signals used, and provided by, microcontroller 110 - 1 is provided to aid the reader's understanding of this embodiment of the present invention. The “nReset” signal is generated after power is removed from the device and subsequently reapplied. This signal causes the device to re-perform calibration before providing service. In this embodiment, the microcomputer 110 - 1 is connected to three user-operated buttons (“ON/OFF” button 120 - 1 , “Down Button” 120 - 2 , and “UP Button” 120 - 3 ). As shown, each button circuit is pulled to a logic high (+5V) by a 100K pull-up resistor. When a user depresses a button, its corresponding switch (S 200 , S 201 , S 202 ) is closed to ground the circuit such that the microcomputer reads a logic zero (0 V) to indicate that the user has made a command. With respect to the ON/OFF button 120 - 1 , if the current state of the wiring device is “OFF,” an actuation of the button 120 - 1 directs the microcontroller to send a signal via lines RC 1 , RC 2 such that the relay turns the load “ON.” When the user depresses the button 120 - 1 again, the same sequence plays out such that the relays turn the load “OFF.” The “down button” circuit 120 - 2 and the “up button” circuit 120 - 3 operate in the same identical way that the ON/OFF button operates. An actuation of the up-button 120 - 3 is interpreted as a command to increase the power delivered to the load, and an actuation of the down-button 120 - 2 is just the opposite. [0102] In particular, when the down-button 120 - 2 is depressed, the software in the microcontroller changes the PWM signal that drives the dimmer circuit 30 so that the lighting load is incrementally dimmed. (Of course, the circuit may also be used to slow an electric motor, e.g., a fan motor). Conversely, when the up-button 120 - 3 is depressed, the software in the microcontroller changes the PWM signal that drives the dimmer circuit 30 so that the lighting load is incrementally raised. With respect to button 120 - 3 , the programming header 120 - 4 allows a person having the appropriate skill level to reprogram and/or debug the microcomputer 110 when button 120 - 3 is depressed in a predetermined sequence. The sequence is an indication to the microcomputer 110 - 1 that a data input device (a host computer interface, RF interface, keyboard, etc.) is being connected to header 120 - 4 and a reprogramming sequence is being initiated. The microcontroller 110 - 1 is also connected to the display circuit (shown in FIG. 4 ) by a serial clock signal (SCL) and a serial data signal (SDA) to provide a serial bit stream that corresponds to the appropriate device display settings (which are described below in conjunction with the circuit depicted in FIG. 4 ). The display settings are transmitted to the display circuit 130 when the settings are changed by a user input command and refreshed periodically. In one embodiment of the present invention, the microcomputer refreshes the settings every 300 msec, or at a 3.3 Hz rate. Of course, any suitable refreshing rate may be selected depending on the processor load. [0103] The zero cross signal (ZC) is provided by the power PCB 10 - 1 and is paired with the VREF FOR Z-CROSS signal. These signals comprise a differential input signal that is provided to a differential comparator disposed inside the microcomputer 110 - 1 . The differential signal eliminates common-mode noise to prevent any false zero cross detections by the microcomputer 110 - 1 . Stated differently, the reference timing provided by the zero cross detector of the present invention is substantially immunized from common mode noise to substantially eliminate spurious timing signals. The purpose and function of the remaining signals will become apparent when their corresponding circuits are described herein. [0104] Referring to FIG. 4 , a detailed circuit diagram of a user display circuit 130 in accordance with an embodiment of the present invention is disclosed. As alluded to above, the signals SCL and SDA are provided to an I/O expander circuit 130 - 1 in display circuit 130 . The I/O expander 130 - 1 is configured to receive the serial bit stream (SDA) from the microcomputer 110 - 1 and convert it into a parallel data output for use by the display LEDs 130 - 2 , 130 - 3 , 130 - 4 and 130 - 5 . In the embodiment of FIG. 4 , seven (7) bar graph LEDs 130 - 2 are included to provide the user with an indication of the dimmer setting. For example, if one LED is ON and the other six LEDs are OFF, the bar graph indicates to the user that the light level setting is at its lowest setting. Conversely, if all seven (7) LEDs in the bar graph 130 - 2 are illuminated, the dimmer is at its highest setting. [0105] The LEDs 130 - 3 , 130 - 4 , and 130 - 5 work in conjunction with the transistor 130 - 6 . When the lighting load or the motor load is turned OFF by the relay circuit 40 , the microcomputer transmits an appropriate bit command such that transistor 130 - 6 is turned ON. This causes current to flow through the locator LED 130 - 5 . Once the lighting load is turned OFF, the LED 130 - 5 is turned ON to provide the user with a relatively small locator light that tells the user where to find the light switch in the darkened room. When current flows through LED 130 - 5 , however, current cannot flow through the (−) LED 130 - 3 and the (+) LED 130 - 4 because both of these LEDs are biased OFF. In other words, these LEDs are presented with the same voltage potential at their anodes and cathodes such that current cannot flow. The purpose of the (−) LED and the (+) LED displays is to direct the user to the down button 120 - 2 and the up button 120 - 3 , respectively. When the load is turned OFF, the dimming function is irrelevant and the −LED and the +LED are OFF to further indicate that the load is OFF. [0106] Referring to FIG. 5 , a detailed circuit diagram of the power supply circuit in accordance with an embodiment of the present invention is disclosed. The power supply includes a half-wave rectifier circuit that is comprised of diodes 200 - 202 . The half-wave rectified DC signal is shown as HVDC. The half-wave rectified signal HVDC is employed by the regulator circuit 20 - 1 to further provide the power supply reference signals +5V and ground (GND) for the processor circuit 110 . [0107] The diodes 200 - 202 are disposed in parallel with each other so that the AC power signal may be provided to the power supply via the hot/load pin or by either of the traveler pins (T 1 , T 2 ). The utility of this parallel arrangement becomes more apparent in FIGS. 10A-10C and the description thereof. Needless to say, this feature yields a universal dimmer that can be placed in either switch position of a retrofit three-way switch arrangement. Regardless of the switch position, or which traveler pin the relay circuit 40 is connected, one of diodes 200 - 202 will furnish current to the power supply. Note also that diodes 204 - 206 (as a group) are placed in parallel with diodes 200 - 202 to provide the zero cross detector 20 - 2 with the half-wave rectified DC signal so that the zero cross detector 20 - 2 provides the zero cross (ZC) signal described above. Diodes 204 - 206 are also disposed in parallel with each other (like diodes 200 - 202 ) so that AC power signal may be provided to the zero-cross detection circuit 20 - 2 via the hot/load pin or either of the traveler pins (T 1 , T 2 ). Regardless of the switch position, or which traveler pin the relay circuit 40 is connected to, one of diodes 204 - 206 will furnish current to the zero-cross detection circuit. [0108] Referring to FIG. 6 , a detailed circuit diagram of the dimmer circuit in accordance with the present invention is disclosed. The microcomputer 110 - 1 controls the dimmer circuit 30 by way of the pulse width modulation (PWM) signal. Specifically, the PWM signal propagates at logic levels (+5V, GND) and controls the operation of transistor 30 - 1 . The width of the PWM pulse is varied to control the amount of power provided to the load, whether a lamp load or a motor load. The PWM signal comprises at least one pulse in an AC line cycle. In one embodiment of the invention, the PWM signal may provide a plurality of pulses within an AC half cycle. By using pulse width modulation, the present invention may be used as a universal dimmer device that can control any type of lighting load by varying the duty cycle of the pulse relative to the zero cross. In operation, when the PWM signal is high, the transistor 30 - 1 conducts through the opto-coupler 30 - 2 to turn transistors 30 - 3 and 30 - 4 ON in accordance with the appropriate timing. Note that for the MOSFET implementation shown in FIG. 6 , two transistors ( 30 - 3 , 30 - 4 ) are required for operation. This is due to the internal body diode inherent in MOSFET technology; one MOSFET blocks a portion of the positive AC half cycle, and the other blocks a portion of the negative half-cycle to the load. The timing of the PWM pulse is of course controlled by the microcomputer and it is timed relative to the zero crossing of the AC cycle. As noted above, dimming is accomplished in the forward phase by switching the load current ON sometime after the zero-crossing of the AC half-cycle and turned OFF at the next zero-crossing of the AC waveform. Conversely, in reverse phase control, the load current is turned ON when the zero-crossing is detected and turned OFF sometime before the next zero-crossing is detected. [0109] Because the PWM pulse is controlled by the microcomputer 110 - 1 (with a high degree of granularity) while simultaneously monitoring the load current, the dimmer circuit may employ forward phase control to drive certain optimized ELV, CFL and LED devices. At the outset of the process, the microcontroller transmits a PWM signal at a very low duty cycle and increases the duty cycle incrementally until the I SNS AMP OUT signal (from the load current detector 112 ) indicates that there is a load current being drawn. If the fixture is an incandescent one, the load current in this region (low duty cycle) is substantially linear with respect to the PWM duty cycle. If the fixture is an LED fixture, the load current will not be present until the duty cycle has been increased to a certain threshold. Thus, the present invention employs a control loop that optimizes the PWM duty cycle for any given lighting load. Moreover, the microcomputer 110 - 1 may adjust the PWM signal to operate in forward phase or reverse phase by operation of the software. Again, as those skilled in the art will appreciate, forward phase control is appropriate for conventional incandescent lighting, magnetic low voltage (MLV) lighting fixtures, conventional fluorescent lighting fixtures employing electronic ballasts (EFL), and halogen lighting devices. Reverse phase control is generally appropriate for electronic low voltage (ELV) lighting. Bulbs designed as higher efficiency 120V incandescent replacements, including LED bulbs and compact florescent lights (CFL) typically perform better with forward phase control. [0110] In one embodiment of the present invention, thermal sensors (Ts) 52 and 54 measure the heat being generated by the MOSFETs to obtain an estimate of power consumption. Thus, the sensor 52 is positioned proximate the transistors 30 - 3 , 30 - 4 to obtain a measurement of the heat being generated thereby. The second sensor 54 is disposed in a region of the device that experiences the ambient temperature of the device 10 . The microcomputer 110 - 1 is programmed to calculate the temperature difference to determine the amount of thermal energy generated by the transistors 30 - 3 , 30 - 4 . As those skilled in the art will appreciate, there is a relationship (I 2 R) between the dissipated heat and the power. [0111] (Again, with respect to FIGS. 10A-10C , the AC signal may be provided via the HOT/LOAD terminal and the dimmed signal by way of the SWITCH POLE terminal, or vice-versa, depending on which switch position the device 10 occupies in the three-way arrangement). Finally, note that wire-loop 50 - 1 is connected between transistor 30 - 4 and the SWITCH POLE terminal. The wire loop passes through the current sensor toroid 50 depicted in FIG. 8 . [0112] Referring to FIG. 7 , a detailed circuit diagram of the switch relay circuit 40 in accordance with an embodiment of the present invention is disclosed. Again, the latching relay 40 - 1 may be configured to support both SPST applications as well as single pole double throw (SPDT) applications. In the SPDT application the relay 40 - 1 is moved between a first switch position that connects T 1 and SWITCH POLE, and a second switch position that connects T 2 with SWITCH POLE. The relay command signals RC 1 and RC 2 are logic level signals that control transistors 40 - 3 and 40 - 2 , respectively. If the latching relay is in the first switch position, the microcontroller 110 - 1 will provide a pulse via the relay command signal RC 2 to cause the switch 40 - 1 to toggle into the second switch position. Conversely, if the latching relay is in the second switch position, the microcontroller 110 - 1 will provide a pulse via relay command signal RC 1 to cause the relay 40 - 1 to toggle back into the first switch position. [0113] Referring to FIG. 8 , a diagrammatic depiction of the load sensor 50 in accordance with the present invention is disclosed. As noted above, a wire loop connected to the SWITCH POLE terminal is disposed through the center of the toroid to create a transformer circuit. The wire loop 50 - 1 carries the load current and functions as the transformer primary. The current sensor 50 may also be implemented as a toroid. [0114] Referring to FIG. 9 , a detailed circuit diagram of a load sensor detector circuit 112 in accordance with the present invention is disclosed. In this embodiment the detector 112 is configured as a threshold detector 112 - 1 that compares the I SNS signal from sensor 50 described above, with a predetermined threshold value. In this particular embodiment, the detector 112 - 1 provides a logic signal to the microcomputer 110 - 1 . In one embodiment, if the load current is greater than about 10 mA, the detector 112 - 1 is configured to provide a logic one (+5V) signal. If the load current is below the threshold, a logic zero (0 V) is provided. Those skilled in the art will appreciate that the threshold level is adjustable and depends on the level of sensitivity desired and the type of load. In this embodiment, the microcomputer 110 - 1 is signaled by I SNS AMP OUT when a minimal amount of current is being drawn by the load. [0115] As embodied herein and depicted in FIGS. 10A-10C , diagrammatic depictions of a three-way switch arrangement in accordance with the present invention are disclosed. FIG. 10A shows a typical three-way switch arrangement wherein the line voltage (i.e. 120 VAC) is connected to the pole of a first SPDT switch S 1 and the load is connected to the pole of a second SPDT switch S 2 . In this diagram, the load L is ON by virtue of the switch positions of S 1 and S 2 . Toggling either S 1 or S 2 into a second switch position will turn the load OFF. The present invention may replace either one of the switches S 1 and S 2 . [0116] FIG. 10B shows device 10 of the present invention being connected to switch S 1 in FIG. 10A . Thus, the hot AC line signal is directed into the dimmer/latching switch 30 / 40 via the T 1 terminal, and further directed into the regulator 20 - 1 via diode 200 and the zero-cross detector 20 - 2 via diode 204 . The dimmed power is provided to the load via the HOT/LOAD terminal. If the device 10 is switched such that AC power is provided via the T 2 terminal, the diode arrangement ( 201 , 205 ) ensures that AC power is directed to the regulator and the zero-cross detector. [0117] FIG. 10C shows device 10 of the present invention being connected to switch S 2 in FIG. 10A . In this configuration, the AC hot is directed into the dimmer/relay circuits 30 / 40 via the relay pole line; dimmed power is provided to the load via terminal T 1 . Because of the diode circuit described previously, AC hot is provided to the regulator 20 - 1 via diode 202 and to ZC Detector 20 - 2 via diode 206 . [0118] As embodied herein and depicted in FIG. 11 , a block diagram of the AC power circuitry in accordance with another embodiment of the present invention is disclosed. This embodiment is identical to the one depicted in FIG. 2A with the exception that there is no neutral terminal or ground terminal available for circuit reference. Thus, this device 10 may be employed in a retrofit/remodeling project where the existing device box does not include a neutral conductor. [0119] Referring to FIG. 12 , a detailed circuit diagram of the power supply depicted in FIG. 11 is disclosed. Because there is no neutral connection, two less diodes are required. The zero-cross detection circuit 20 - 2 is essentially the same as the one depicted in FIG. 5 . The linear regulator circuit produces a virtual ground node approximately 24V below the Hot/Load terminal. D 203 is biased with R 200 and R 201 to produce 24V, and Q 200 provides current amplification and improved load regulation compared with a zener regulator acting alone. U 200 further regulates the 24V down to 5V for use by the dimmer control circuitry. R 202 -R 205 provide current limiting in the event of a short circuit on the 24V or 5V supplies. [0120] Referring to FIG. 13 , a detailed circuit diagram of the dimmer circuit 30 depicted in FIG. 11 is disclosed. As before, the microcomputer 110 - 1 controls the dimmer circuit 30 by way of the PWM signal. The PWM signal is at logic levels (+5V, GND) and controls the operation of transistor 30 - 1 . When transistor 30 - 11 is turned ON at a predetermined point in the AC half cycle, an appropriate amount of current is provided to the triac 30 - 10 to turn it ON such that dimmed power is provided to the load. L 300 , R 300 , and C 300 implement RFI filtering to minimize electromagnetic interference into nearby electronic equipment. [0121] Referring to FIG. 14 , a detailed circuit diagram of the switch relay depicted in FIG. 11 is disclosed. This circuit is identical to the one depicted in FIG. 7 , and therefore, no further description is required with the exception that the transistors 40 - 2 and 40 - 3 are connected to the HOT/LOAD terminal instead of the rectified HVDC signal ( FIG. 7 ). As stated previously, the circuit's ground reference is 24V below the Hot/Load terminal; therefore this configuration provides 24V for driving the relay coil. [0122] As embodied herein and depicted in FIGS. 15A-15B , diagrammatic depictions of another three-way switch arrangement in accordance with the present invention are disclosed. These diagrams illustrate that the embodiment of FIG. 11 may replace either switch S 1 or switch S 2 in FIG. 10A . This capability is enabled by the diode arrangement 200 - 203 and the analysis is similar to the one provided in conjunction with FIGS. 10A-10C . [0123] As embodied herein and depicted in FIG. 16 , a flow chart diagram illustrating a software auto-calibration sequence 1600 in accordance with the present invention is disclosed. In step 1602 the device is energized and in step 1604 the microcontroller sets the duty cycle of the PWM pulse at an initial value that may be thought of as an idling value. In step 1606 , the microcomputer 110 - 1 waits a predetermined time to determine if the load current is detected. In steps 1608 - 1612 , the PWM pulse width is increased until either the load current is detected or a maximum width value is exceeded. If the maximum width value is exceeded, the microcontroller 110 - 1 assumes that the load is turned OFF by the companion switch (S 1 or S 2 ) and goes back to the initial PWM setting in step 1604 . The cycle is repeated until the load current is detected in step 1614 . The microcontroller 110 - 1 , of course, knows the PWM value when load current is detected. (As noted below, the microcontroller 110 - 1 may include PWM v. load current curves that can be used to identify a given load). [0124] Load current detection is achieved when the threshold detector 112 - 1 finds that the I SNS signal from sensor 50 reliably exceeds the threshold. In one embodiment, I SNS is sampled 1000 times over a second. If at least 800 of the samples do not indicate load presence, the lamp is either OFF or flickering; and the microcontroller 110 - 1 increases the PWM width in accordance with an approximately 10 VRMS step increase in voltage to the lamp. This process of checking the threshold detector and widening the PWM step is iterated until the lamp is either reliably ON (i.e., at least 800 samples are detected to indicate the presence of the load) or the maximum width is exceeded. The microcontroller ceases the iterative process when about 70 VRMS is provided to the load. [0125] The automatic calibration process (steps 1602 - 1628 ) can be accomplished in a matter of seconds. In one embodiment the calibration is initiated when an upstream breaker is opened momentarily and then closed to restore the voltage on the dimmer's power supply. In another embodiment, the automatic calibration takes place when a button on the dimmer is actuated by the user. In another approach, the automatic calibration takes place each time a switch is toggled to apply power to the load. When the load current is detected in step 1614 , the microcontroller 110 - 1 uses the output voltage as the starting output voltage for the lower calibration level (in step 1616 ). [0126] The voltage at which the lamp is reliably ON is indicative of the type of load in use. For example, if the absolute value of the load current is low, it may indicate that the load is an LED lamp. As another example, the microcontroller 110 - 1 is configured to track the number of load indication samples in a given measurement interval and determine the type of load by noting the change (the number of load indication samples) from interval to interval. In the subsequent steps ( 1618 - 1628 ), the microcontroller 110 - 1 continues to incrementally increase the voltage until the estimated power (based on the sensed current) exceeds an upper threshold ( 1620 ) for the load; this value is used to find the upper calibration value ( 1626 ). The calibration values are stored in memory (step 1628 ) for use by the microcontroller 110 - 1 . [0127] The microcontroller 110 - 1 is configured to determine that the lighting device is a capacitive load device when it detects current spikes in a forward phase mode. Conversely, the microcontroller 110 - 1 will detect current spikes when an inductive load is when the dimmer is operating in a reverse phase mode. [0128] The microcontroller 110 - 1 is configured to determine the type of load based on whether or not there is an inrush current when the load is turned ON. The microcontroller 110 - 1 may be configured to compare the inrush characteristics of a given load to in-rush curves stored in memory (e.g. the characteristic curve for a tungsten filament load). Unlike traditional incandescent bulbs, modern high-efficiency bulbs such as CFLs and LEDs do not turn on smoothly when the terminal voltage is increased from zero volts. Rather, these bulbs will not conduct (turn ON) until a specified voltage is applied (i.e., the specified voltage is a function of the bulb design). For example, one manufacturer's LED bulb may be configured to turn ON at 40Vrms, while another manufacturer's LED bulb may turn ON at 60Vrms. Additionally, if the bulb voltage is maintained at or near the bulb's turn ON voltage, the bulb may flash (flicker). (Hence, the microcontroller 110 - 1 can perform the calibration routine at steps 1602 - 1628 based on the curves stored in memory). [0129] When high-efficiency bulbs (e.g., LEDs, CFL, etc.) are used, the dimmer's output voltage should not drop below a stable turn-on voltage specified for the bulb. Dimmers designed for use with high-efficiency bulbs are typically calibrated at the factory so that the bulb operates at a specified low-end voltage based on the type of high-efficiency bulb the dimmer is designed for. On the other hand, when the intended use of a dimmer contemplates using various kinds of load types, a number of calibration strategies must be considered. For example, one calibration strategy that may be considered includes setting the minimum dimmer output voltage to a relatively level so that all types of bulbs will turn ON without flashing. This procedure can be done during manufacturing. The downside of this approach is that the resulting dimming range will be unacceptably narrow for many load types. A design approach that can be considered includes providing the dimmer with a manual calibration feature that allows the end user to calibrate the dimmer after installation. One drawback to this approach is that the user/installer must perform an additional procedure after dimmer installation. This approach may result in unacceptable dimmer operation if the user fails to perform the calibration properly. (This may occur if the instructions are poorly written, the user/installer fails to follow the instructions, or both). [0130] Instead of using the aforementioned approaches, the present invention embeds a calibration algorithm into the dimmer so that the microcontroller 110 - 1 automatically calibrates the dimmer for the load being used. As noted above, auto-calibration can occur when power is first applied to the dimmer after installation. (The instant disclosure also teaches that the calibration algorithm can be performed when: (1) an upstream breaker is momentarily opened and re-closed; (2) when a button on the dimmer is actuated by the user; and/or each time a switch is toggled to apply power to the load). In reference, e.g., to FIG. 16 , the dimmer of the present invention implements the auto-calibration feature by automatically increasing the dimming voltage in predetermined increments while estimating the power being delivered to the load at each increment. (See steps 1602 - 1622 at FIG. 16 ). When the microcontroller 110 - 1 senses a sudden increase in sensed current, i.e., the microcontroller 110 - 1 detects the load, it performs the auto-calibration routine by setting the incremental dimmer voltage at the lower calibration value (see, e.g., steps 1614 - 1616 at FIG. 16 ). As explained above, the memory of the microcontroller 110 - 1 can include a look-up table that has load (bulb) characteristic curves based on the initial sensed load current vs. load turn-on voltage. At this point, the calibration routine continues to sense the load current for each incremental output voltage until the load power reaches the upper threshold value. [0131] As noted herein (above and below), one embodiment of the present invention uses a current sensor to estimate load power, and microcontroller 110 - 1 to perform the calibration routine and control the dimming. This implementation is suitable for use in either single pole or 3-way switch installations. [0132] As embodied herein and depicted in FIG. 17 , a flow chart diagram illustrating a main software program is disclosed. After initialization and calibration ( 1702 ), the microcomputer 110 - 1 reads and records (in step 1704 ) the user input from, e.g., the button inputs described herein. (See, e.g., FIG. 3 ). If an ON/OFF command is issued by the user, the microcomputer 110 - 1 directs the relay circuit 40 accordingly. After determining if a load current is present (step 1708 ), the computer 110 - 1 adjusts the PWM dimmer setting in accordance with user commands ( 1710 ) and updates the display LEDs ( 1712 ) accordingly. This process is performed continually thereafter. [0133] As embodied herein and depicted in FIG. 18 , a flow chart diagram 1800 illustrating a software zero cross interrupt routine 1800 is disclosed. In step 1804 , the microcomputer 110 - 1 determines whether device 10 should operate in forward phase control (FPC) or in reverse phase control (RPC) using any one of the methods described herein. In the forward phase, the load current is switched ON a predetermined time after the zero-crossing of the AC half-cycle and turned OFF at the next zero-crossing of the AC waveform. Conversely, in reverse phase control, the load current is turned ON immediately after the zero-crossing is detected and turned OFF at a predetermined time before the next zero-crossing is detected. The predetermined time intervals described above can be implemented by scheduling a software load timer interrupt. [0134] As embodied herein and depicted in FIG. 19 , a flow chart diagram 1900 illustrating a software load timer interrupt routine is disclosed. As an extension to discussion on FIG. 18 above, the load timer interrupt turns the load current off when operating in reverse phase, and turns the load current on when operating in forward phase. [0135] As embodied herein and depicted in FIG. 20 , a front isometric view of a power control device 10 in accordance with an embodiment of the present invention is disclosed. Device 10 includes a switch cover 204 disposed on heat sink assembly 202 . The power handling PCB 10 - 1 is disposed under the heat sink 202 and within the back body member 200 . FIG. 21 is a rear isometric view of the power control device depicted in FIG. 20 and shows the back body member 200 and the heat sink 202 . [0136] Referring to FIG. 22 , a rear isometric view of the heat sink assembly of the power control device depicted in FIG. 20 is disclosed. In this view, the back body member 200 is removed so that the internal components may be seen. Specifically, the separator member 202 - 2 is shown as being connected to the front of the heat sink 202 . The pins of the MOSFETs 30 - 3 , 30 - 4 and the interface circuit 10 - 3 are shown as extending through the separator 202 - 2 so that they may be coupled to the PCB 10 - 1 . [0137] In FIG. 23 , another rear isometric view of the heat sink assembly is shown. Again, the back body member 200 is removed so that the internal components may be seen. Moreover, the power handling printed circuit board 10 - 1 is added to the components shown in FIG. 22 . In this view, the sensor 50 , the sensor wire 50 - 1 , the relay 40 and various other components are shown as being disposed on the power handling PCB 10 - 1 . Note that ground clip spring 202 - 1 is attached to the rear side of the heat sink 202 . The spring clip 202 - 1 is configured to engage a front portion of a frame assembly (not shown in this view). Reference is made to U.S. patent application Ser. No. 13/680,675, which is incorporated herein by reference as though fully set forth in its entirety, for a more detailed explanation of A MODULAR ELECTRICAL WIRING DEVICE SYSTEM and the associated framing system. [0138] Referring to FIG. 24 , a front isometric view of the device depicted in FIG. 20 is disclosed. In this view, the aesthetic cover 204 removed. Thus, the switch actuator 204 - 2 is shown to include a central aperture that accommodates the locator LED 130 - 5 . Note also that the dimmer cover assembly 206 is seated within a portion of the switch actuator 204 - 2 . FIG. 25 is a front isometric view of FIG. 20 with the aesthetic actuator cover 204 and the dimmer cover 206 removed; thus, the dimmer control switches 120 - 2 , 120 - 3 are visible in this view. Snap elements 202 - 3 are formed in the separator 202 - 2 and are use to engage the dimmer cover 206 and secure it to the assembly. Snap elements 202 - 3 are also pivot points that allow the dimmer cover 206 to rotate in order to actuate dimmer control switches ( 120 - 2 , 120 - 3 ). [0139] Referring to FIG. 26 , a front isometric view of the heat sink assembly disposed within the back body member 200 is shown. Note that the logic PCB 10 - 2 is mounted to the front side of the heat sink 202 . The microcomputer 110 - 1 is mounted on the PCB 10 - 2 . The switches 120 - 1 , 120 - 2 and 120 - 3 , as well as LED indicators 130 - 2 , are also mounted on the PCB 10 - 2 . [0140] Referring to FIG. 27 , a front isometric view of the device is shown (with the heat sink 202 removed). In this view, the separator member 202 - 2 can be clearly seen. This view also shows the MOSFETS 30 - 3 and 30 - 4 being electrically connected to the PCB 10 - 1 and extending through the openings in the separator 202 - 2 . The snap elements 202 - 3 are also clearly shown in this view; and as noted above, the snap elements 202 - 3 accommodate corresponding snap-in elements that are formed in the dimmer cover 205 (not shown). The separator 202 - 2 also includes trunions 202 - 4 at either end. The trunions 202 - 4 accommodate the snap-openings 204 - 12 in the functional actuator 204 - 2 (See FIG. 29 ). Trunions 202 - 4 allow the functional actuator 204 - 2 to rotate; the rotation of the functional actuator 204 - 2 allows switch 120 - 1 to be engaged. Finally, the separator 202 - 2 includes a spring arm 202 - 5 that is configured to bias the functional actuator 204 - 2 upwardly. [0141] Referring to FIG. 28 , an exploded view of the power control device depicted in FIG. 20 is disclosed. The device 10 includes an aesthetic cover 204 that includes an LED lens 204 - 1 disposed in a central portion thereof. In an embodiment of the invention, lens 204 - 1 is a thin section of cover 204 . The aesthetic cover further includes an opening 204 - 6 that accommodates the dimmer switch cover 206 . The dimmer switch cover 206 includes a light pipe structure 206 - 1 that is held in place within the dimmer cover 206 by an alignment mask 206 - 2 . The dimmer cover 206 , the light pipe 206 - 1 and the alignment mask 206 - 2 are configured to be disposed within opening 204 - 5 formed in one side of the functional switch actuator 204 - 2 . The functional switch actuator 204 - 2 includes a central opening 204 - 3 . The logic PCB 10 - 2 is shown over top of the front side of the heat sink 202 . The two MOSFETs 30 - 3 and 30 - 4 are coupled to the bottom of heat sink 202 by insulator members 30 - 3 , 30 - 40 , respectively. Of course, the MOSFETs 30 - 3 and 30 - 4 are electrically connected to the power handling PCB 10 - 1 via openings in the separator 202 - 2 . The entire assembly is disposed within back body member 200 . See, e.g., FIGS. 24-27 . [0142] Referring to FIG. 29 , a bottom isometric view of the functional actuator 202 - 2 is disclosed. The central portion of the functional switch 204 - 2 includes a central opening 204 - 3 that may accommodate an LED. At one side of the functional switch 204 - 2 there are snap-in elements ( 204 - 10 , 204 - 11 ) that are configured to mate with the snap-elements 202 - 6 formed in the separator. (See FIG. 27 ). The snap-in elements ( 204 - 10 , 204 - 11 ) are bearing surfaces for the springs 202 - 6 , and also serve to limit the spring-biased rotation. Recessed surface 204 - 13 engages the switch 120 - 1 when the cosmetic actuator 204 is depressed, and it opposes the spring biased rotation. At the opposite side, trunion mounts 204 - 12 accommodate the trunions 202 - 4 formed in the separator 202 - 2 . The trunions 202 - 4 allow the functional switch 204 - 2 to move in the process of manually activating switch 120 - 1 . The tray portion 204 - 5 ( FIG. 28 ) which accommodates the dimmer cover assembly 206 , also includes light isolation openings 204 - 6 for the light pipe element 206 - 1 ( FIG. 28 ). [0143] In reference to FIGS. 30-31 , detailed isometric views of the dimmer actuator cover 206 depicted in FIG. 20 are disclosed. FIG. 30 shows the underside of the dimmer cover 206 . An alignment mask 206 - 2 is disposed overtop the light pipe structure 206 - 1 to prevent undesired light leakage from the light pipe. The down button light pipe 206 - 5 , the up button light pipe 206 - 6 , and the LED bar graph light pipes 206 - 7 are shown extending through the mask portion 206 - 2 . In FIG. 31 , the mask portion 206 - 2 is removed such that the light pipe structure 206 - 1 can be clearly seen within the dimmer cover 206 . [0144] Referring to FIG. 32 , a cross-sectional view of the power control device 10 depicted in FIG. 20 is disclosed. This view shows the aesthetic cover 204 disposed over the functional switch 204 - 2 and other elements underneath, such as the logic PCB 10 - 2 , separator 202 - 2 and the power handling PCB 10 - 1 . Aesthetic cover 204 is configured to be removable by the user as is dimmer cover 206 . [0145] While several inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. There is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto; inventive embodiments may be practiced otherwise than as specifically described and claimed. [0146] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. [0147] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms. [0148] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. [0149] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and/or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc. [0150] It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited. [0151] Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about” and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged; such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. [0152] The recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. [0153] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not impose a limitation on the scope of the invention unless otherwise claimed. [0154] No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. [0155] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of” shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

The present invention is directed to an intelligent dimmer that is capable of “learning” the type of load it is controlling, and adjusts its operating parameters accordingly. The present invention can adaptively drive electrical loads over a wide range of wattages. The intelligent dimmer of the present invention is configured to automatically calibrate itself based on the load current demands of a particular electrical load. The intelligent dimmer of the present invention also adaptively limits in-rush currents to extend the life expectancy of the solid state switching components used therein.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional of U.S. application Ser. No. 11/777,845, filed Jul. 13, 2007, which claims priority under 35 U.S.C. §119(e)(1) to U.S. provisional patent application Ser. No. 60/807,367, filed Jul. 14, 2006, and U.S. Provisional patent application Ser. No. 60/888,647, filed Feb. 7, 2007. U.S. application Ser. No. 11/777,845 also claims priority under 35 U.S.C. §119 to German patent application serial No. 10 2006 032 810.8, filed Jul. 14, 2006. The contents of these applications are hereby incorporated by reference in its entirety. FIELD [0002] The disclosure relates to optics, such as, for example, microlithographic projection exposure apparatus illumination optics, as well as related systems, methods, components and devices. BACKGROUND [0003] Typically, a microlithographic projection exposure apparatus includes an illumination system and a projection objective. SUMMARY [0004] The disclosure relates to optics, such as, for example, microlithographic projection exposure apparatus illumination optics, as well as related systems, methods, components and devices. [0005] In one aspect, the disclosure features a microlithographic projection exposure apparatus illumination optical system. The illumination optical system has an optical path, an object plane and a pupil plane. The illumination optical system is configured so that, during use when light passes through the illumination optical system along the optical path, the illumination optical system illuminates a field of the object plane with the light. The illumination optical system includes an optical module that is configured so that during use the first optical module sets a first illumination setting in the pupil plane of the illumination optical system. The illumination optical system also includes an additional optical module that is configured so that during use the second optical module sets a second illumination setting in the pupil plane of the illumination optical system. In addition, the illumination optical system includes at least one decoupling element in the optical path upstream of the two optical modules. The decoupling element is configured so that during use the decoupling element provides light to at least one of the two optical modules. The illumination optical system further includes at least one coupling element in the optical path downstream from the two optical modules. The at least one coupling element is configured so that during use the at least one coupling element provides the light which has passed through at least one of the two optical modules to the illumination field. [0006] In another aspect, the disclosure features a microlithographic projection exposure apparatus that includes a projection objective and the illumination optical system described in the preceding paragraph. [0007] In a further aspect, the disclosure features a method that includes using the illumination system described in the preceding two paragraphs to make a microstructured component. [0008] In an additional aspect, the disclosure features a system that includes a first optical module configured to be used in addition to a second optical module of illumination optics in a microlithographic projection exposure apparatus so that during use, when incorporated into the microlithographic projection exposure apparatus, the first and second optical module provide first and second illumination settings, respectively, in a pupil plane of the illumination optics. The system also includes at least one decoupling element configured to be incorporated into the illumination optics so that during use the at least one decoupling element is located in the optical path upstream from the first and second optical modules so that the at least one decoupling element provides light to at least one of the first and second optical modules. The system further includes at least one coupling element configured to be incorporated into the illumination optics so that during use the coupling element is located in the optical path downstream from the first and second optical modules so that it provides light from at least one of the first and second optical modules to the illumination field. [0009] In one aspect, the disclosure features a a microlithographic projection exposure apparatus that has a pupil plane. The microlithographic projection exposure apparatus includes a device configured so that, during use when light passes through the microlithographic projection exposure apparatus, the device alters an illumination setting in the pupil plane within a time period of 10 milliseconds or less. [0010] In another aspect, the disclosure features a microlithographic projection exposure apparatus that has a pupil plane and that is configured to image an object into an image plane using multiple, nearly periodic pulses of light. The microlithographic projection exposure apparatus includes a device configured so that during use the device changes an illumination setting in the pupil plane from a first illumination setting to a second illumination setting. [0011] In a further aspect, the disclosure features a system that includes a microlithographic projection exposure apparatus configured to image an object into an image plane using multiple, nearly periodic pulses of light. The microlithographic projection exposure apparatus includes a first optical element and a second optical element. The microlithographic projection exposure apparatus also includes a device configured so that during use the device alters the number of pulses between the first and second optical elements. [0012] In an additional aspect, the disclosure features a microlithographic projection exposure apparatus configured to image an object into an image plane using multiple, nearly periodic pulses of light having an average pulse duration. The microlithographic projection exposure apparatus includes a first optical element and a second optical element. The microlithographic projection exposure apparatus also includes a device configured so that during use the device alters the average pulse duration between the first and second optical elements. [0013] Embodiments can optionally provide one or more of the following advantages. [0014] In some embodiments, the systems can allow for relatively fast changes in optical settings (e.g., illumination settings) during use. In some instances, fast changes of illumination settings can be desirable for multiple exposure in order to illuminate the mask briefly at two different illumination settings. [0015] In certain embodiments, the systems can allow for relatively fast changes in optical settings (e.g., illumination settings) during use with relatively little or no movement of optical components and/or with relatively little or no light loss. [0016] In some embodiments, such advantages can be provided, for example, by including in the system at least two optical modules that are adjusted (e.g., preadjusted) to produce specific illumination settings (e.g., polarization settings) such that it is possible to switch between the optical modules as appropriate. Optionally, switching between optical modules can be accomplished mechanically, such as, for example, by temporarily introducing a mirror into the illumination light path. Alternatively or additionally, switching between optical modules can be accomplished by modifying a characteristic of the illumination light. Under some circumstances, this can allow relatively substantially different illumination settings to be accessible with relatively little switching effort. Optionally, switching can be performed between more than two optical modules (e.g., by cascaded decoupling elements and coupling elements), which can, for example, allow for switching between more than two different illumination settings (e.g., more than two different polarization states). [0017] In some embodiments, the change in light characteristic (e.g., polarization state) can take place in one second or less (e.g., one microsecond or less, 100 ns or less, 10 ns or less). [0018] In some embodiments, use of polarization-selective beam splitter can result in an illumination light beam with a relatively large cross-section which can advantageously result in a relatively low-energy and/or relatively low-intensity load on the beam splitter. In certain embodiments, depending on the illumination light wavelength used, a polarization cube or a beam splitter cube used in a variation can be made of CaF 2 or of quartz. Optionally, use can also be made of a, for example, optically coated beam splitter plate which lets through light having a first polarization direction and reflects light having a second polarization direction. [0019] Use of a Pockels cell can provide good switching between polarization states. Optionally, a Kerr cell which is suitable for changing the beam geometry can also be used. Also optionally, an acousto-optic modulator can be used as the light-characteristic changer in order to change the beam direction (the beam direction being modified by Bragg reflection). [0020] In some embodiments, a light-characteristic changer can be particularly well suited for obtaining a light load which is distributed over the optical components and well adapted to the time characteristic of light emission of commonly used light sources. [0021] In certain embodiments, a polarization changer can be an example of a light-characteristic changer where the light characteristic is changed by mechanically switching an optical component. The optical component can be switched so that, before and after switchover, the illumination light passes through the same optically active surface of the optical component. This is the case, for example, when a single λ/2 plate is used as a polarization changer. With other embodiments of the light-characteristic changer, various optically active regions of the optical component are used by this mechanical switching. The control expense for such a light-characteristic changer can be relatively low. [0022] In some embodiments, use of a second polarization optical component can create the possibility of using a polarization optical beam splitter to extract the illumination light. The first polarization optical component of the polarization changer can be a λ/2 plate having, in its operating position, an optical axis which is oriented differently compared to the second polarization optical component. The first polarization optical component can be a free passage through the polarization changer. [0023] In certain embodiments, changeover between the two optical modules can be obtained by temporarily inserting a mirror into the ray path of the illumination light. This variation requires relatively inexpensive control. [0024] Examples of decoupling elements are known, for example, from metrology and optical scanner technology. [0025] In some embodiments, a decoupling element can be relatively light weight. [0026] In certain embodiments, the first illumination setting and the second illumination setting generally differ. However, in some embodiments, the second illumination setting may also be exactly the same as, or similar within predetermined tolerance limits to, the first illumination setting, so the first illumination setting does not significantly differ from the second illumination setting in any light characteristic. In such cases, the change between the illumination settings can still lead to a reduction in the optical load on the components of the first and the second optical module, as merely a respective portion of the overall illumination light acts on these optical modules. Illumination settings are also different if they differ exclusively in the polarization of the illumination light fed to the object or illumination field. Such a difference in polarization may be a difference in the type of polarization of the light passing through a local point in a pupil of the illumination optics. The pupil is in this case the region through which illumination light passes of a pupil plane which is, in turn, optically conjugate with a pupil plane of an objective, in particular a projection objective, downstream from the illumination optics. Alternatively or additionally, a difference in polarization may also be a difference in the spatial distribution of the orientation of the type of polarization relative to the pupil coordinate system beyond the various local points of the pupil. The term “type of polarization” or “polarization state” refers in the present document to linearly and/or circularly polarized light and to any form of combinations thereof such as, for example, elliptically, tangentially and/or radially polarized light. It is, for example, possible in a first illumination setting to irradiate the entire object field with a first illumination light linear polarization state which is constant over the pupil. A second illumination setting can use light having polarization rotated for this purpose through a constant angle, for example through 90°, with respect to an axis of rotation. The polarization distribution does not in this case vary on rotation about the axis of rotation through the aforementioned constant angle. Alternatively, it is possible in a first illumination setting to illuminate the pupil with a first spatial polarization distribution, for example with the same polarization over the entire pupil and in a second illumination setting to illuminate portions of the pupil with a first polarization direction of the illumination light and other portions of the pupil with a further polarization direction of the illumination light. In this case, not only the polarization direction but also the polarization distribution in the pupil is varied. Under the terms of the present application, illumination settings are different if their intensity distribution as a scalar variable and/or their polarization distribution as a vectorial variable differs over the pupil. The differing polarization states may be described as vectorial variables in the pupil based on vectorial E-field vectors of the illumination light. The pupil may in this case also have a non-planar (a curved surface). The intensity distribution is then described as a scalar variable and the polarization distribution is then described as a vectorial variable over this curved surface. [0027] In some embodiments, the illumination settings may differ merely in terms of the polarization state, i.e. for example in the type of polarization (linear, circular) and/or in the polarization direction and/or in the spatial polarization distribution. This can allow the polarization state to be adapted to changing imaging features, especially features resulting from the geometry of the structures to be imaged. [0028] In certain embodiments, an optical delay can allow defined time synchronization of the illumination light guided through the first optical module relative to the illumination light guided through the second optical module in the light path after the coupling element. This can be used to homogenize in time a dose of light onto the optical components from the coupling element in order thus to reduce, especially in the case of pulsed light sources, the deposition of energy per pulse in the optical components. This can apply especially to the optical components of the projection exposure apparatus arranged after the coupling element in the direction of the illumination or projection beam such as, for example, a condenser, a REMA (reticle/masking) objective, a reticle or a mask, optical components of a projection objective, immersion layers, the photoresist, the wafer and the wafer stage. The optical delay component may be an optical delay line arranged in the light path of the first optical module or in the light path of the second optical module. The optical delay can be adjustable via the optical delay component, and this can be achieved, for example, via a linear sliding table movable along a path over which the illumination light can be guided several times and a mirror, in particular a retroreflecting mirror, rigidly connected to the linear sliding table. Alternatively, and especially for setting relatively short delay paths, the optical delay component may be configured as an optically transparent and optically denser medium having a predetermined optical path. Use may also be made of a combination of an optical delay component wherein the optical delay is based on enlargement of the pure path and an optical delay component wherein the optical delay is based on a light path in an optically denser medium. [0029] In some embodiments, the illumination optics can have a relatively small peak load on the reticle and/or on optical components downstream from the decoupling beam splitter. [0030] In some embodiments, by changing the light characteristic during the illumination light pulse, this pulse can be split into two light pulse parts which are then shaped into different illumination settings. This can advantageously reduce the illumination light load on the components, in particular the local load on the components. By changing the light characteristic during the illumination light pulse, if a laser is chosen as the light pulse source, it is possible to work with half the laser repetition rate, twice the pulse energy and double the pulse duration. The single pulse energy is in this case the integral of the power of the individual pulse over the pulse duration thereof. In some instances, such lasers can be relatively easily integrated in a microlithographic projection exposure apparatus. [0031] In certain embodiments, the optical modules can be subjected to a relatively low mean light output to which the optical modules are subjected because not all light pulses from the light source are conducted through the same optical module. Assuming appropriate synchronization, a decoupling element can be used instead of the light-characteristic changer. In such instances, the decoupling element can let through every second light pulse, for example, and the light pulses in between are reflected by the mirror elements of the decoupling element to the other optical module. The light-characteristic changer may, for example, be configured in such a way that the light characteristic changes between two successive light pulses. [0032] In some embodiments, illumination light which is generated by the at least two light sources can be coupled into an illumination light beam by a coupling optical device and this light beam illuminates the illumination field. A beam splitter of the same type as the coupling or decoupling beam splitter can be used to obtain coupling; this is, however, not compulsory. Alternatively, it is possible, for example, to merge at least two illumination light beams from the light sources via coupling mirrors or coupling lenses. [0033] In certain embodiments, the illumination system can be relatively compact. [0034] In certain embodiments, a control system can allow proportional adjustment of illumination of the illumination field with various preset illumination settings. These components can be produced by time-proportional illumination, i.e. by sequential illumination initially with a first and then with at least one other illumination setting or by intensity-proportional illumination, i.e. parallel illumination of the illumination field with a plurality of illumination settings with a preset intensity distribution. The main control system can also be connected to the coupling element by signals for control purposes if this is necessary in order to obtain changeover between optical modules. [0035] In some embodiments, the control system can acquire information concerning the relevant illumination setting via its signal links to the components of the illumination system, can specify specific preset lighting settings by acting on the adjustment of the optical modules and make additional adaptations, for example via the reticle masking system or scan speeds. [0036] The systems can be used, for example, in methods to manufacture components. [0037] In some embodiments, the optics can be in the form of a supplementary module for a microlithographic projection exposure apparatus. The supplementary module can, for example, be retrofitted to an existing illumination optics and an existing illumination system. This can, for example, allow the optics described herein to be used in pre-existing systems. This can, for example, reduce the cost and/or complexity associated with using the optics described herein. [0038] In certain embodiments, the individual components of the supplementary module, can be designed and developed as already described above in relation to the illumination optics according to the disclosure and the illumination system according to the disclosure. The further illumination setting provided by the supplementary module may differ from the illumination setting of the first optical module. In some applications, the further illumination setting can, in this case too, correspond within predetermined tolerance limits in all light characteristics to the illumination setting of the first optical module. [0039] A number of references are incorporated herein by reference. In the event of an inconsistency between the explicit disclosure of the present application and the disclosure in the references, the present application will control. [0040] Embodiments of the disclosure are described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0041] FIG. 1 is a schematic representation of an embodiment of a microlithographic projection exposure apparatus. [0042] FIGS. 2 to 4 are schematic representations of two successive light pulses from a light source of a projection exposure apparatus. [0043] FIG. 5 is a schematic representation of an embodiment of a microlithographic projection exposure apparatus. [0044] FIGS. 6 to 9 are schematic representations of two successive light pulses from a light source of a projection exposure apparatus. [0045] FIGS. 10 and 11 are schematic representations of embodiments of a microlithographic projection exposure apparatus [0046] FIGS. 12 and 13 are schematic representations of embodiments of microlithographic projection exposure apparatuses. [0047] FIG. 14 is a schematic representation of an embodiment of a decoupling element and an embodiment of a coupling element. [0048] FIG. 15 is a schematic representation of an embodiment of a decoupling element and an embodiment of a coupling element. [0049] FIG. 16 is a schematic representation of an embodiment of a polarization changer. [0050] FIG. 17 is a schematic representation of an embodiment of a microlithographic projection exposure apparatus. [0051] FIGS. 18 and 19 are schematic representations of embodiments of illumination settings. [0052] FIGS. 20 and 21 are schematic representations of embodiments of mask structures. [0053] FIGS. 22 and 23 are schematic representations of embodiments of illumination settings. [0054] FIGS. 24 and 25 are schematic representations of embodiments of mask structures. [0055] FIGS. 26 and 27 are schematic representations of embodiments of illumination settings. [0056] FIGS. 28 and 29 show the two masks which are successively to be imaged onto the same wafer to be illuminated by double exposure with the illumination settings in FIGS. 26 and 27 , respectively. DETAILED DESCRIPTION [0057] FIG. 1 shows a microlithographic projection exposure apparatus 1 which can be used, for example, in the fabrication of semiconductor components and other finely structured components and which uses light in the vacuum ultraviolet range (VUV) to achieve resolutions of fractions of a micrometre. A light source 2 is (e.g., an ArF excimer laser with a working wavelength of 193 nm) produces a linearly polarized light beam 3 which is coaxially aligned with an optical axis 4 of an illumination system 5 of the projection exposure apparatus 1 . Other UV light sources (e.g., a F 2 laser with a working wavelength of 157 nm, an ArF laser with a working wavelength of 248 nm, a mercury vapour lamp with a working wavelength of 368 nm or 436 nm, light sources with wavelengths below 157 nm) can optionally be used as the light source 2 . [0058] Light exiting from the light source 2 is initially polarized perpendicularly to the plane of projection in FIG. 1 (s-polarization). This is indicated in FIG. 1 by the individual dots 6 on the light beam 3 . This linearly polarized light from the light source 1 first enters a beam expander 7 which can be formed, for example, as a mirror arrangement (such as described, for example, in DE 41 24 311, which is hereby incorporated by reference) and is used to reduce the coherence and increase the cross-section of the beam. After the beam expander 7 , the light beam 3 passes through a Pockels cell 8 which is an example of a light-characteristic changer. In general, as long as no voltage is applied to the Pockels cell 8 , the light beam 3 is still s-polarized as it leaves the Pockels cell 8 . The light beam 3 then passes through a decoupling beam splitter 9 which is an example of a decoupling element and is formed as a polarization cube made of CaF 2 or quartz. The decoupling beam splitter 9 lets the s-polarized light beam 3 through in the direction of the optical axis 4 and the beam passes through a first diffractive optical element (DOE) 10 . The first DOE 10 is used as a beam-shaping element and is located in an entry plane of a first lens group 11 positioned in the ray path downstream therefrom. [0059] The first lens group 11 includes a zoom system 11 a and a subsequent axicon setup 11 b. The zoom system 11 a is doubly telecentric and designed as a scalar zoom so that optical imaging with preset magnification is achieved between one entry plane and one exit plane of the zoom system 11 a. The zoom system 11 a can also have a focal-length zoom function so that triple Fourier transformation, for example, is performed between the entry plane and the exit plane of the zoom system 11 a. The illumination light distribution set after the zoom system 11 a is subjected to radial redistribution by the axicon elements of the axicon setup which can be displaced axially towards each other provided that a finite distance is set between the opposite-facing conical axicon surfaces of the axicon elements. If this gap is reduced to zero, the axicon setup 11 b basically acts as a plane-parallel plate and has practically no influence on the local distribution of illumination created by the zoom system 11 a. The axial clearance between the optical components of the zoom system 11 a and the axicon setup 11 b can be adjusted by actuators. [0060] The first lens group 11 is part of a pupil forming element which is used to set a defined local two-dimensional illumination intensity distribution for illumination light from the light source 2 in a pupil forming plane 12 of the illumination system 5 located downstream of lens group 11 (the illumination pupil or illumination setting). [0061] The pupil forming plane 12 which is a pupil plane of the illumination system 5 coincides with the exit plane of the first lens group 11 . A further optical raster element 13 is located in the immediate vicinity of the exit plane 12 . A coupling optic 14 located downstream therefrom transfers the illumination light to an intermediate field plane 15 in which a reticle masking system (REMA) 16 , which is used as an adjustable field stop, is located. The optical raster element 13 has a two-dimensional arrangement of diffractive or refractive optical elements and has several functions. On the one hand, incoming illumination light is shaped by the optical raster element 13 so that, after passing through subsequent coupling optic 14 in the region of the field plane 15 , it illuminates a rectangular shaped illumination field. The optical raster element 13 with a rectangular radiation pattern is also referred to as a field defining element (FDE) and generates the main component of the etendue and adapts it to the desired field size and field shape in the field plane 15 which is conjugate with a mask plane 17 . The optical raster element 13 can be designed as a prism array in which individual prisms arranged in a two-dimensional field introduce locally determined specific angles in order to illuminate the field plane 15 as required. The Fourier transformation performed by coupling optic 14 that each specific angle at the exit of the optical raster element 13 corresponds to a location in the field plane 15 whereas the location of the optical raster element 13 (its position in relation to the optical axis 4 , determines the illumination angle in the field plane 15 ). The beams emerging from the individual optical elements of the optical raster element 13 are superimposed in the field plane 15 . It is also possible to construct FDE 13 as a multistage honeycomb condenser with microcylinder lenses and diffusing screens. By constructing FDE 13 and its individual optical elements appropriately, it is possible to ensure that the rectangular field in the field plane 15 is substantially homogeneously illuminated. FDE 13 is thus also used as a field shaping and homogenising element for homogenising the field illumination so that a separate light-mixing element, for instance an integrator rod acting through multiple internal reflection or a honeycomb condenser, can be dispensed with. This can make the optical setup in this region especially axially compact. [0062] A downstream imaging objective 18 , which is also referred to as a REMA objective, images the intermediate field plane 15 with the REMA 16 onto a reticle or its surface 19 in the mask plane 17 on a scale which can be, for example, from 2:1 to 1:5 and, in the embodiment shown in FIG. 1 , is approximately 1:1. Imaging takes place without an intermediate image so that there is precisely one pupil plane 21 between the intermediate field plane 15 , which corresponds to an object plane of imaging objective 18 and an image plane of imaging objective 18 which coincides with the mask plane 17 and corresponds to the exit plane of the illumination system and, at the same time, an object plane of downstream projection objective 20 . The latter is a Fourier transformed plane relative to the exit plane 17 of the illumination system 5 . A deflection mirror 22 , tilted at 45° with respect to the optical axis 4 and positioned between the pupil plane 21 and the mask plane 17 , makes it possible to install a relatively large illumination system 5 , which is several metres long, horizontally and, at the same time, keep the reticle 19 horizontal. [0063] Those optical components which guide illumination light from the light source 2 and, from it, form the illumination light which is directed at the reticle 19 are part of the illumination system 5 of the projection exposure apparatus. Downstream from the illumination system 5 there is a device 23 for holding and manipulating the reticle 19 arranged so that a pattern on the reticle falls in object plane 17 of the projection objective 20 and, in this plane, can be moved with the aid of a scan drive for scan operation in a scan direction which is perpendicular to the optical axis 4 . [0064] The projection objective 20 is used as a reduction objective and forms an image of the reticle 19 on a reduced scale, for example on a 1:4 or 1:5 scale, on the wafer 24 which is coated with a photoresistive layer or photoresist layer, the light-sensitive surface of which lies in image plane 25 of the projection objective 20 . Refractive, catadioptric or catoptric projection objectives are possible. Other reduction scales, for instance greater minification, up to 1:20 or 1:200 are possible. [0065] The semiconductor wafer 24 which is to be exposed is secured by the device 26 configured to hold and/or manipulate it which includes a scanner drive in order to move the wafer 24 , in synchronism with the reticle 19 , perpendicularly to the optical axis 4 . These movements can be parallel to each other or anti-parallel, depending on the design of the projection objective 20 . The device 26 , which is also referred to as a wafer stage, and the device 23 , which is also referred to as a reticle stage, are component parts of a scanner which is controlled via a scan controller. [0066] The pupil forming plane 12 is located on or close to a position which is optically conjugate with next downstream pupil plane 21 and with image-side pupil plane of the projection objective 20 . This way, the spatial and local light distribution in the pupil plane 27 of the projection objective 20 can be determined by the spatial light distribution and local distribution in the pupil forming plane 12 of the illumination system 5 . Between each of the pupil surfaces 12 , 21 and 27 , there are field surfaces in the optical ray path which are Fourier-transformed surfaces relative to the relevant pupil surfaces. This can allow for a defined local distribution of illumination intensity in the pupil forming plane 12 can result in a specific angular distribution of the illumination light in the region of the downstream field plane 15 which, in turn, can correspond to specific angular distribution of the illumination light which falls onto the reticle 19 . Together with the first DOE 10 , the first lens group 11 forms a first optical component 28 configured to set a first illumination setting in the illumination pupil 12 . [0067] In some embodiments, the illumination system 5 can allow for relatively fast modification of the illumination pupil 12 during an illumination process (e.g., for an individual reticle 19 ). This can make double exposure or other multiple exposure possible at short time intervals. [0068] A second optical module 29 , which is located in the decoupling path 29 a of the decoupling beam splitter 9 , can be used for fast modification of the illumination setting in the pupil forming plane 12 . The second optical module 29 includes the second DOE 30 and a second lens group 31 which is, in turn, divided up into a zoom system 31 a and the axicon setup 31 b. The two optical modules 28 , 29 are of similar construction. The optical effect and the layout of the individual optical components of the zoom system 31 a, the axicon setup 31 b and of second DOE 30 are, however, different from the first optical module 28 so that illumination light from the light source 2 which passes through the second optical module 29 is influenced so that a second illumination setting which differs from the first illumination setting created by the first optical module 28 is produced in the pupil forming plane 12 . [0069] Decoupling path 29 a is indicated in FIG. 1 by the dashed line. In the decoupling path 29 a, the illumination light is guided in the parallel polarization direction (p-polarization) relative to the plane of projection in FIG. 1 which is indicated in FIG. 1 by double arrows 32 which are perpendicular to the optical axis in the decoupling path 29 a. [0070] A deflection mirror 33 is positioned, in the same way as the deflection mirror 22 , between the decoupling beam splitter 9 and the second DOE 30 . Another deflection mirror 34 is positioned between the axicon setup 31 b of the second lens group 31 and a coupling beam splitter 35 which is constructed as a polarization cube like the decoupling beam splitter 9 . The coupling beam splitter 35 is an example of a coupling element. The coupling beam splitter 35 is located in the optical path between the axicon setup 11 b of the first lens plane 11 and the optical raster element 13 . The illumination light guided onto the decoupling path 29 a is deflected by the coupling beam splitter 35 so that, downstream from the coupling beam splitter, it travels precisely along the optical axis 4 . [0071] High voltage, typically 5 to 10 kV, can be applied to the Pockels cell 8 in order to obtain a rapid change of illumination setting. When high voltage is applied to the Pockels cell 8 , the polarization of the illumination light can be rotated (e.g., from s to p) within a few nanoseconds. The p-polarized illumination light is extracted in the decoupling path 29 a because a polarizer in the decoupling beam splitter 9 acts as a reflector for p-polarization. In the decoupling path 29 a, the illumination light is subjected to different setting adjustment to the s-polarized illumination light which is not extracted. After deflection by the deflection mirror 34 via the coupling beam splitter 35 , the polarizer of which acts as a reflector for p-polarized light, p-polarized illumination light which has passed through the second optical module 29 is coupled again in the direction of the optical axis 4 . [0072] The light source 2 can generate, for example, laser pulses having a duration of 150 ns or 100 ns and a single pulse energy of, for example, 30 mJ or 15 mJ at a repetition rate of, for example, 6 kHz. [0073] FIGS. 2 to 4 show various examples of switching times for high-voltage switching instants t s of the Pockels cell 8 . FIGS. 2 to 4 all schematically show consecutive individual rectangular pulses L from the light source 2 at interval t z =t 2 -t 1 which corresponds to the reciprocal of the 6 kHz repetition rate. In the switching-time example in FIG. 2 , the Pockels cell 8 switches between every two laser pulses L. Laser pulse L 1 shown on the left in FIG. 2 passes through the Pockels cell without voltage being applied and therefore remains p-polarized. The polarization of subsequent laser pulse L 2 is rotated through 90° because switching instant t s has occurred and it therefore passes through the decoupling path 29 a. The next laser pulse (not shown) passes through the Pockels cell 8 without its polarization being altered. In the case of the switching-time example in FIG. 2 , every second laser pulse is therefore fed through the decoupling path 29 a whereas the other laser pulses are not decoupled. The reticle 19 is therefore subjected to alternate illumination with two different illumination settings which correspond to the setting of the optical modules 28 , 29 respectively and the laser pulses for each illumination setting have a repetition rate of 3 kHz. The radiation load incident on the reticle and the optical components of the illumination system downstream from the decoupling beam splitter 9 is determined by the energy and peak intensity of each individual laser pulse L. [0074] In the switching-time example in FIG. 3 , the Pockels cell 8 switches while a single laser pulse L is passing through it. Individual laser pulse L is therefore split into pulse parts L 1 , L 2 . In the example in FIG. 3 , polarization of the leading laser pulse part L 1 is unaffected and it therefore remains s-polarized. In contrast, the polarization of the subsequent laser pulse part L 2 is subjected to rotation because it passes through the Pockels cell 8 after switching instant t s , and is extracted and creates a different illumination setting to laser pulse part L 1 . The two laser pulse parts L 1 and L 2 have a pulse duration equivalent to roughly half the pulse duration of the non-divided laser pulse which, in this embodiment, is therefore around 50 or 75 ns. The energy of the laser pulse parts is roughly half the energy of individual laser pulses (7.5 mJ or 15 mJ). The polarization of leading laser pulse part L 2 of the subsequent laser pulse in FIG. 3 is rotated and is therefore p-polarized. Voltage is removed from the Pockels cell 8 at switching instant t s , so that the polarization of next laser pulse part L 1 is no longer affected and therefore remains s-polarized. This second laser pulse is therefore split. Switching repeats accordingly during laser pulses for subsequent laser pulses from the light source 2 which are not shown. In the switching-time example in FIG. 3 , one laser pulse part is therefore fed through the decoupling path 29 a, i.e. [0075] through the optical module 29 , and the other laser pulse part is fed through the other optical module 28 . In this switching-time example, the reticle 19 is illuminated at an effective repetition rate of 6 kHz with the first illumination setting and illuminated at the same effective repetition rate of 6 kHz with the second illumination setting. Because of the halving of the pulse energy in the laser pulse parts, the peak load on the reticle and the optical components downstream from the decoupling beam splitter 9 is reduced by a factor of roughly 2 . In practice, this reduction factor can be even higher because the two different illumination settings generated by the optical modules 28 , 29 , in general, impinge on different regions of the pupil with different polarization characteristics. [0076] In the switching-time example in FIG. 4 , the Pockels cell 8 switches three times for each laser pulse L. In the case of leading laser pulse L shown on the left in FIG. 4 , high voltage is initially applied to the Pockels cell but this voltage is then switched off and applied again. The left-hand laser pulse shown in FIG. 4 is therefore split into leading laser pulse part L 1 with s-polarization, subsequent laser pulse part L 2 with p-polarization, yet another subsequent laser pulse part L 1 with s-polarization and final laser pulse part L 2 with p-polarization. In the case of laser pulse L shown on the right in FIG. 4 , these conditions are precisely reversed because when the Pockels cell 8 first switches during laser pulse L shown on the right in FIG. 4 , the high voltage is initially switched off. The right-hand laser pulse L shown in FIG. 4 therefore has a leading p-polarized laser pulse part L 2 , a subsequent s-polarized laser pulse part L 1 , a subsequent p-polarized laser pulse part L 2 and a final s-polarized laser pulse part L 1 . In the case of the switching-time example in FIG. 4 , the illumination light impinges on the reticle 19 with an effective repetition rate of 12 kHz for both illumination settings. In the case of the switching-time example in FIG. 4 , the light pulse parts L 1 and L 2 have a pulse duration of approximately 25 or 37.5 ns and a pulse energy of approximately 3.75 or 7.5 mJ. Because the individual light pulses are quartered by the triple switching of the Pockels cell 8 during one light pulse L, the peak load on the reticle 19 and on the optical components downstream from the decoupling beam splitter 9 drops by a factor of 4. [0077] Depending on polarization state, the service life of optical materials depends not only on peak illumination power H, but also on the number of pulses N and the pulse duration T of the laser pulses. Various theoretical models in relation to this, which are familiar to persons skilled in the art, have been developed. One of these models is the polarization double refraction model according to which the load limit of optical materials depends on the product H×N. With the so-called compaction model or the microchannel model, the load limit depends on the product H 2 ×N/T. [0078] Comparative analysis shows that it is possible to use a laser 2 with a halved repetition rate (number of pulses N/2), doubled pulse laser power (2H) and doubled pulse duration (2T) for double exposure by once-only changeover by the Pockels cell 8 during one laser pulse. Such lasers with a half repetition rate and doubled power are one possible way of increasing the performance of current lithographic lasers and can be implemented simply. Using the light-characteristic changer 8 makes it possible to use a 6 kHz laser in microlithographic applications which were previously only possible using a 12 kHz laser. The constructional requirements placed on the laser light source become commensurately less demanding. [0079] A polarization-changing light-characteristic changer other than the Pockels cell 8 can be used to influence the polarization of the illumination light, for example a Kerr cell. [0080] Instead of polarization, a different characteristic of the illumination light can be influenced by the light-characteristic changer, for example the light wavelength. In this case, dichroitic beam splitters can be used as the decoupling beam splitter 9 and as the coupling beam splitter 35 . [0081] The beam geometry of the light beam 3 or its direction can be the light characteristics that are modified by an appropriate light-characteristic changer in order to switch between the two optical modules 28 , 29 . A Kerr cell or an acousto-optic modulator can be used as an appropriate light-characteristic changer. [0082] An embodiment with two optical modules 28 , 29 is described above. It is equally possible to provide more than two optical modules and switch between them. For example, another Pockels cell which rotates the polarization of the illumination light at preset switching times, thereby causing extraction into another decoupling load which is not shown in FIG. 1 , can be provided between the decoupling beam splitter 9 and DOE 10 or in the decoupling path 29 a. This way, it is possible to obtain fast changeover between more than two illumination settings. [0083] The Pockels cell 8 can also be located inside the light source 2 and chop the laser pulses generated in the light source 2 into several light pulse parts of the same kind as parts L 1 and L 2 . This can result in little or no laser coherence and can, for example, reduce the possibility of undesirable interference in the mask plane 17 . [0084] FIG. 5 shows an embodiment of an illumination system. Components that are identical to those already described above with reference to FIGS. 1 to 4 have the same reference numerals and are not individually described again. The illumination system in FIG. 5 can be implemented in combination with all the design variations that are described above with reference to the embodiment in FIGS. 1 to 4 . [0085] In addition to the light source 2 , the illumination system 5 in FIG. 5 has another light source 36 , the internal construction of which can be identical to that of the light source 2 . Downstream from the light source 36 , there is a beam expander 37 , the construction of which can be identical to that of the beam expander 7 . A light beam 38 from the light source 36 is expanded by the beam expander 37 (e.g., as already described in connection with the light beam 3 from the light source 2 ). Downstream from beam expander 37 , there is a Pockels cell 39 . After exiting the other light source 36 , the light beam 38 is also initially s-polarized as indicated by dots 6 on the light beam 38 . As long as no voltage is applied to the Pockels cell 39 , the light beam 38 remains s-polarized after passing through the Pockels cell 39 . After the Pockels cell 39 , the light beam 38 impinges on a second decoupling beam splitter 40 . The light beam splitter 40 lets s-polarized light through and reflects p-polarized light to the right by 90° in FIG. 5 . A polarization-selective deflection element 41 is located downstream from the second decoupling beam splitter 40 in the beam splitter's forward direction. The deflection element is for s-polarized light which is incident from the direction of the second decoupling beam splitter 40 , reflecting to the right by 90° in FIG. 5 , and it lets p-polarized light through unimpeded. [0086] Using the illumination system 5 in FIG. 5 , light from the two light sources 2 and 36 can be injected optionally into the two optical modules 28 , 29 . [0087] When no voltage is applied to the two Pockels cells 8 and 39 , the light source 2 illuminates the first optical module 28 because s-polarized light beam 3 from the two decoupling beam splitters 9 and 40 is allowed through unimpeded. As long as no voltage is applied to the two Pockels cells 8 and 39 , the second light source 36 illuminates the second optical module 29 because the second decoupling beam splitter 40 lets the s-polarized light of the light beam 38 through unimpeded and this s-polarized light is deflected into the second optical module 29 by the deflection element 41 . [0088] When voltage is applied to the first Pockels cell 8 but not to the second Pockels cell 39 , the two light sources 2 and 36 illuminate the second optical module 29 . The now p-polarized light from the first light source 2 is extracted from the decoupling beam splitter 9 , as described above, into the decoupling path 29 a and, after deflection by the deflection mirror 33 , passes through the deflection element 41 unimpeded so that it can enter the second optical module 29 . The optical path of the light beam 38 from the second light source 36 remains unchanged. [0089] When voltage is not applied to the first Pockels cell 8 , but is applied to the second Pockels cell 39 , the two light sources 2 and 36 illuminate the first optical module 28 . The s-polarized light from the first light source 2 can pass through the two decoupling beam splitters 9 and 40 unimpeded and enters the first optical module 28 . The light of the light beam 38 from the second light source 36 rotated into p-polarization by the second Pockels cell is reflected through 90° by the second decoupling beam splitter 40 and enters the first optical module 28 . [0090] When light from the two light sources 2 and 36 collectively impinges on one of the optical modules 28 , 29 , the light from the two light sources 2 and 36 which collectively passes through the optical module 28 or 29 can have two different polarization states. [0091] P-polarized light which has passed through the first optical module 28 is reflected by the coupling beam splitter 35 in FIG. 5 upwards along the optical path 42 , from where it has to be brought back in the direction of the optical axis 4 by another appropriate coupling device. The same applies to s-polarized light which is fed through the second optical module 29 and which passes through the coupling beam splitter 35 , without being deflected thereby, in the direction of the optical path 42 . [0092] When voltage is applied to the two Pockels cells 8 and 39 , light from the light source 2 is conducted through the second optical module 29 and light from the light source 36 is conducted through the first optical module 28 . FIGS. 6 and 7 show the possible characteristics, as a function of time, of the intensities I 1 of the light pulses L from the first light source 2 and of the intensities I 2 of the light pulses L′ from the second light source 36 . The two light sources 2 and 36 are synchronized with each other so that light pulses L′ are generated during the gaps between two light pulses L. Two light pulses L and L′ therefore do not impinge simultaneously on the second decoupling beam splitter 40 and the deflection element 41 . Also, beyond the coupling beam splitter 36 , laser pulses L and L′ do not simultaneously impinge on downstream optical components of the illumination system 5 or on the reticle 19 and the wafer 24 . As described above with reference to FIGS. 2 to 4 , laser pulses L and L′ can be split into two or more laser pulse parts L 1, 2 and L′ 1, 2 by one or more optical polarization components and appropriate switching times. This reduces the illumination light load on the optical components as already described above with reference to FIGS. 2 to 4 . [0093] Two pulsed light sources with pulse waveforms according to FIGS. 6 and 7 can also be combined upstream from a single Pockels cell of the illumination system. To achieve this, light 3 , for example, from the second light source 2 upstream from beam expander 7 can be injected into the optical path of the light beam 3 with the aid of a perforated mirror 2 a which is tilted 45° relative to the optical axis 4 . The light source 2 ′, the light beam 3 ′ and the perforated mirror 2 a are shown in a dashed line in FIG. 1 . The light beam 3 ′ is also s-polarized. The light beam 3 ′ from the light source 2 ′ ideally has a mode which carries practically no energy in the region of a central hole in the perforated mirror 2 a. The light beam 3 from the light source 2 passes through the hole in the perforated mirror 2 a. The beam expander 7 is then illuminated by merged light beams 3 and 3 ′. The Pockels cell 8 is then used as a common Pockels cell in order to influence the polarization state of the light beams 3 and 3 ′. [0094] FIGS. 8 and 9 show another way of reducing the illumination light load on individual components of the illumination system 5 in FIG. 5 in situations where the light pulses L and L′ of the two light sources 2 and 36 overlap in time. FIG. 8 shows the intensity I 1 of the light pulses L from the light source 2 . FIG. 9 shows the intensity I 2 of the light pulses L′ from the light source 36 . The Pockels cell 8 is deenergized before the arrival of the first laser pulse L at t=t s0 . Laser pulse part L 1 therefore passes through the first optical module 28 . The second Pockels cell 39 is also deenergized at t=t s0 in synchronism with the first Pockels cell 8 . Switching instant t s0 coincides with the centre of a laser pulse L′ of the second light source 36 , so that subsequent light pulse part L′ 2 is then conducted through the second optical module 29 . In period T D between the rising edge of laser pulse L and the trailing edge of laser pulse L′ following switching instant t s0 during which the two laser pulses L and L′ overlap, the two laser pulses L and L′ are therefore separately conducted through the optical modules 28 , 29 so that there is no simultaneous loading by the two laser pulses L and L′. At the next switching instant t s1 , voltage is applied to the two Pockels cells 8 and 30 in synchronism. Switching instant t s1 coincides with the centre of laser pulse L of the light source 2 . Subsequent laser pulse part L 2 therefore passes through the second optical module 29 . In contrast, laser pulse part L′ 1 of next laser pulse L′ of the second light source 36 which overlaps with this laser pulse part L 2 is conducted through the first optical module 28 . [0095] At switching instant t s2 in the centre of next laser pulse L′, the process described with reference to switching instant t s0 repeats. The frequency of switching instants t s is twice that of the laser pulses of individual light sources 2 and 36 , with laser pulse L and L′ of one light source being halved and with switching between two laser pulses L′ and L of the other light source. This circuit ensures that light from the two light sources 2 and 36 is never conducted through a single optical module 28 or 29 and this reduces the load on the individual optical components of the optical modules 28 , 29 accordingly. [0096] FIG. 10 shows an embodiment of the illumination system 5 . Components that are identical to those already described above with reference to FIGS. 1 to 9 have the same reference numerals and are not individually described again. The variation in FIG. 10 is equivalent to the variation in FIG. 5 , apart from the way in which the light from the second light source 36 is extracted. In FIG. 10 , the decoupling beam splitter 9 , which already extracts the light beam 3 of the light source 2 , is used to extract the light beam 38 of the second light source 36 . [0097] The decoupling beam splitter 9 firstly lets the s-polarized light of the light source 2 and secondly lets the s-polarized light of the light source 36 through unimpeded, so that s-polarized light from the light source 2 impinges on the first optical module 28 and s-polarized light from the second light source 36 impinges on the second optical module 29 . The decoupling beam splitter 9 reflects the p-polarized light of the light sources 2 and 36 through 90 ° respectively, so that p-polarized light from the second light source 36 impinges on the first optical module 28 and p-polarized light from the first light source 2 impinges on the second optical module 29 . [0098] In terms of coupling, the variation in FIG. 10 corresponds to that in FIG. 5 . [0099] In terms of the switching times of the Pockels cells 8 and 39 , the examples of switching times described above with reference to FIGS. 6 to 9 can also be used in the system shown in FIG. 10 . [0100] In some embodiments, the change in light characteristic in order to change the optical path between the optical modules 28 , 29 can take place in one second or less (e.g., one microsecond or less, 100 ns or less, 10 ns or less). [0101] Switching of the Pockels cells 8 and 39 can be periodic at a fixed frequency. This frequency can be around 1 kHz, for example. Other exemplary frequencies are in the range from 1 Hz to 10 kHz. [0102] By changing the light characteristic, it is believed that it is possible to ensure that the maximum laser power per laser pulse after creating an illumination setting in the pupil plane 12 is at least 25 % lower than it would be using a conventional illumination system with the same setting measured at the same location. [0103] The maximum intensity at a specific location in the illumination system can be, for example, up to 25% lower in the case of the designs according to the disclosure than in the case of conventional illumination systems with just one optical module. [0104] Instead of the coupling beam splitter 35 , an optical system which integrates the two optical paths can be provided in the form of, for example, a lens, an objective or a refractive mirror or a plurality of such mirrors. One example of such an optically integrating system is described in WO 2005/027207 A1. [0105] FIG. 11 shows an embodiment of a projection exposure apparatus 1 configured to produce proportional illumination of the illumination field via the first optical module 28 , on the one hand, and via the second optical module 29 , on the other hand, e.g. for specified double exposure of the reticle 19 using the two illumination settings that can be set via the optical modules 28 , 29 . Components of the projection exposure apparatus 1 in FIG. 11 that are identical to those already described above with reference to the projection exposure apparatus 1 in FIGS. 1 to 10 have the same reference numerals and are not individually described again. [0106] The project exposure apparatus 1 in FIG. 11 has a main control system in the form of, for example, a computer 43 (e.g., to specify proportional illumination). The computer 43 is connected to a control module 45 by a signal cable 44 . The control module 45 is connected by signals to the light source 2 by a signal cable 46 , to a light source 2 ′ by a signal cable 47 and to the Pockels cell 8 by a signal cable 48 . The computer 43 is connected to the zoom systems 11 a and 31 a by the signal cables 49 and 50 . The computer 43 is connected to the axicon setups 11 b and 31 b by signal cables 51 and 52 . The computer 43 is connected to the REMA 16 by a signal cable 53 . The computer 43 is connected to the wafer stage 26 by a signal cable 54 and to the reticle stage 23 by a signal cable 55 . The computer 43 has a display 56 and a keyboard 57 . [0107] The computer 43 specifies the switching instants t s for the Pockels cell 8 . By selecting the switching instants over time with the aid of the computer 43 , it is possible to specify the intensity with which reticle 19 is illuminated using either of the two illumination settings that can be produced via the two optical modules 28 , 29 . The switching instants for the Pockels cell 8 can be synchronized with trigger pulses of the light sources 2 and 2 ′ so that switching instants occur in correct phase relation during laser pulses as described above in connection with FIGS. 2 to 8 . [0108] Switching instants t S are specified depending on the particular illumination settings previously set in the optical modules 28 , 29 . The computer 43 receives information regarding the particular previously set illumination setting over the signal cables 49 to 52 . The computer 43 can also actively set a predefined illumination setting by controlling appropriate displacement drives for the zoom systems 11 a and 31 a and for the axicon setups 11 b and 31 b over the corresponding signal cables. [0109] Switching instants t s are also specified depending on the particular scanning process. The computer 43 receives information concerning this from the REMA 16 and stages 23 and 26 via the signal cables 53 to 55 . Depending on the specified value, the computer 43 can also actively change the operating position of the REMA 16 and stages 23 and 26 by controlling appropriate drives via the signal cables 53 to 55 . This way, the computer 43 can, depending on the particular operating situation of the projection exposure apparatus 1 , make sure that each of the two optical modules 28 , 29 contributes sufficient light to illuminate the illumination field on reticle 19 . The computer 43 determines the relevant light contribution by integrating the intensity curves (cf. FIGS. 2 to 4 and FIGS. 7 to 9 ). Any excess light which is not needed for projection exposure can be coupled out of the exposure path by using a second Pockels cell and a downstream polarizer. [0110] The main control system 43 can also be connected by signals to the decoupling element 9 and/or coupling element 35 if this is necessary in order to specify proportional illumination of the illumination field using the illumination settings that can be achieved via the optical modules 28 , 29 . [0111] The main control system 43 makes time-proportional illumination of the illumination field on the reticle 19 possible via the first optical module 28 and the second optical module 29 . Alternatively or additionally, the main control system 43 can also be used to obtain intensity-proportional illumination of the illumination field via the first optical module 28 and the second optical module 29 . For instance, it is possible to illuminate the illumination field at 30% of total intensity via the first optical module 28 and at 70% of total intensity via the second optical module 29 . This can be performed statically so that these percentages do not change over a predefined period. Alternatively, it is also possible to vary these proportions dynamically. To achieve this, the Pockels cell 8 can be driven, for example, by a sawtooth waveform having 1 ns timebase. To achieve this, the control circuit of the Pockels cell 8 can have a least one high-voltage generator. If fast switching between two voltages is desirable, the control circuit of the Pockels cell 8 can have two high-voltage generators. Besides high-voltage switching on a nanosecond timescale, there can also be additional high-voltage switching, for example on a millisecond timescale, so that, measured against the duration of the laser pulses, slow transitions between illumination settings that can be specified via the optical modules 28 , 29 are possible. [0112] FIG. 12 shows an embodiment of the projection exposure apparatus 1 . Components that are identical to those already described above with reference to FIGS. 1 to 11 have the same reference numerals and are not individually described again. [0113] In contrast to the projection exposure apparatus in FIGS. 1 , 5 , 10 and 11 , the projection exposure apparatus 1 in FIG. 12 has pupil forming planes 58 and 59 which are each located in the optical paths to the optical modules 28 , 29 and are therefore directly assigned to them. The pupil forming plane 58 is directly downstream from the axicon setup 11 b of the first optical module 28 . The pupil forming plane 59 is directly downstream from the axicon setup 31 b of the second optical module 29 (located in the decoupling path 29 a ). [0114] In the embodiment in FIG. 12 , the pupil forming planes 58 and 59 replace the pupil forming plane 12 in FIG. 12 . Alternatively, it is possible for the pupil forming planes 58 and 59 to be optically conjugate with the pupil forming plane 12 . [0115] Individual raster elements corresponding to raster element 13 in the projection exposure apparatus 1 in FIG. 1 can be assigned to the pupil forming planes 58 and 59 . [0116] In the case of the embodiment of the illumination system 5 in FIG. 12 , pupil forming, i.e. setting an illumination setting, can be performed by using appropriate optical components in optical modules 28 , 29 , as is known in principle from the prior art, e.g. from WO 2005/027207 A. [0117] Other components for influencing a pupil setting which can be used in optical modules 28 , 29 are described in WO 2005/069081 A2, EP 1 681 710 A1, WO 2005/116772 A1, EP 1 582 894 A1 and WO 2005/027207 A1, which are hereby incorporated by reference. [0118] FIG. 13 shows an embodiment of the illumination system 5 of the projection exposure apparatus 1 . Components that are identical to those already described above with reference to FIGS. 1 to 12 have the same reference numerals and are not individually described again. [0119] In contrast to the illumination systems 5 in FIGS. 1 to 12 , the mechanism for obtaining decoupling between optical modules 28 , 29 in the case of the illumination system 5 in FIG. 13 is not based on influencing a light characteristic which is subsequently used to alter an optical path, but on directly influencing the path of the illumination light. To achieve this, the decoupling element 60 is provided in the form of a mirror element. The decoupling element 60 is located at the position of the decoupling beam splitter 9 , e.g. in the embodiment in FIG. 1 , and can rotate around axis 61 which lies in the projection plane of FIG. 13 . This rotating movement is driven by a rotary drive 62 . The rotary drive 62 is connected to synchronization module 63 by the signal cable 64 . The decoupling element 60 has a disc-shaped mirror mount 65 , part of which is shown in FIGS. 13 and 14 . A multiplicity of individual mirrors 67 are fitted over the circumferential wall 66 of the mirror mount 65 and project beyond said wall. [0120] The representation in FIG. 14 is not true scale. In fact, there can be a large number of individual mirrors 67 , for example several hundred such individual mirrors, on the mirror mount 65 . [0121] In the circumferential direction, the gap between two adjacent individual mirrors 67 is equivalent to the circumferential extent of a single mirror 67 . The individual mirrors 67 all have the same circumferential extent. [0122] When the mirror mount 65 rotates, illumination light is either reflected by one of the mirrors 67 or passes between the individual mirrors 67 and is uneffected. Reflected illumination light impinges on the decoupling path 29 a, i.e. the second optical module 29 . Illumination light which is let through impinges on the first optical module 28 . [0123] In the case of the embodiment in FIG. 13 , a coupling element 68 is located at the position of the coupling beam splitter 35 in the embodiment in FIG. 1 and the coupling element 68 has precisely the same structure as the decoupling element 60 . The coupling element 68 is only shown schematically in FIG. 13 . The coupling element 68 , controlled by control module 63 , is driven in synchronism with the decoupling element 60 so that whenever the decoupling element 60 lets illumination light through, the coupling element 68 also lets illumination light through unaffected. In contrast, when the decoupling element 60 reflects illumination light with one of the mirrors 67 , this extracted illumination light, after passing through the decoupling path 29 a, is reflected by a corresponding individual mirror of the coupling element 68 and is thereby injected into the adjacent common illumination light ray path towards reticle 19 . [0124] The speed of rotation of the coupling element 60 and that of the decoupling element 68 is synchronised with the pulse sequence from the light sources 2 and 2 ′. [0125] Owing to the aspect ratio of the circumferential extent of the individual mirrors 67 relative to the circumferential extent of the gaps between adjacent the individual mirrors 67 of the decoupling element 60 and of the coupling element 68 , it is possible to specify the proportion of illumination via the first optical module 28 on the one hand and via the second optical module 29 on the other hand. Such aspect ratios can be defined by the configuration and arrangement of the individual mirrors 67 on the circumferential wall 66 of the mirror mount 65 (e.g., from 1:10 to 10:1). [0126] FIG. 15 shows an embodiment of the decoupling element 60 which can also be used in this form as the coupling element 68 . The decoupling element 60 is in the form of strip-shaped mirror foil 69 . The mirror foil 69 is divided up into individual mirrors 70 between which there are transparent gaps 71 through which illumination light can pass. The mirror foil 69 is an endless loop which is transported over corresponding guide rollers so that, at the location of the individual mirrors 67 in the embodiment in FIG. 13 , it is transported perpendicularly to the plane of projection through the ray path of illumination light 3 . In general, as long as illumination light is reflected by one of the individual mirrors 70 , it is reflected by the decoupling element 60 into the decoupling path 29 a and injected by the coupling element 68 back into the common ray path towards reticle 19 . The illumination light is not affected by the transparent gaps 71 so that, in the case of the decoupling element 60 , it passes through to the first optical module 28 and, in the case of the coupling element 68 , it passes through to reticle 19 . [0127] The explanations given above regarding aspect ratios in connection with coupling and decoupling elements 60 and 68 in FIG. 14 also apply to the control of the mirror foil 69 driven via control module 63 and to the aspect ratio of the lengths of the individual mirrors 70 and the lengths of the gaps 71 . [0128] FIG. 16 shows a polarization changer 72 which can be used instead of the decoupling element 60 . The polarization changer 72 is installed in the illumination system 5 in FIG. 1 at the location of the Pockels cell 8 . The polarization changer 72 is rotatably driven around the rotation axis 76 which runs parallel to the light beam 3 between the light source 2 and the decoupling beam splitter 9 . The polarization changer 72 is rotatably driven around the rotation axis 76 by an appropriate rotary drive synchronised via control module 63 . The polarization changer 72 has a revolving support 73 with a total of eight revolving receptacles 74 . A significantly larger number of receptacles 74 is possible. A λ/2 plate 75 is fitted in every second receptacle 74 in the circumferential direction. The other four receptacles 74 are empty. The optical axes of the four λ/2 plates 75 in total are therefore arranged so that, when one of the λ/2 plates 75 is in the ray path of the illumination light, the polarization of the illumination light is rotated through 90° as it passes through the λ/2 plate. The polarization changer 72 then has the same function as the Pockels cell 8 when high voltage is applied to it. [0129] When one of the empty receptacles 74 lets the illumination light through unaffected, the polarization changer 72 functions as a deenergized Pockels cell. [0130] A rotatable polarization-changing plate as described, for example in WO 2005/069081 A can be used as an alternative to the polarization changer 72 . [0131] A λ/2 plate placed in the ray path of illumination light beam 3 , for example at the location of the Pockels cell 8 in the setup in FIG. 1 and which replaces the Pockels cell 8 , can also be used as another alternative to the polarization changer 72 . By rotating the λ/2 plate around a rotation axis parallel to illumination light beam 3 which passes through it, the polarization plane of the illumination light can be rotated through 90°, for example, so that the λ/2 plate has a polarization-changing effect equivalent to that of the Pockels cell 8 in the embodiment in FIG. 1 . The optical axis of the λ/2 plate is in the plane of the plate as a rule. Other orientations of the optical axis of the λ/2 plate relative to the plane of the plate are also possible. Polarization-changing elements of the same kind as λ/2 plates are described, for example, in DE 199 21 795 A1, US 2006/0055834 A1 and WO 2006/040184 A2, which are hereby incorporated by reference. [0132] Embodiments are described above assuming that the illumination system already includes two optical modules 28 , 29 . According to the disclosure, it is also possible to retrofit existing projection exposure apparatuses having an optical module equivalent to the first optical module 28 in the embodiments described above with a supplementary module, thereby producing one of the embodiments described above. The retrofit supplementary module includes, besides the second optical module 29 , the decoupling element 9 or 60 and the coupling element 35 or 68 . Depending on the design of the supplementary module, it also has a light-characteristic changer, for example the Pockels cell 8 or the polarization changer 72 . The main control system 43 may also be part of the supplementary module. The supplementary module may also include another light source 2 ′ or 36 with appropriate coupling and decoupling optics (e.g., as described above in connection with FIGS. 1 and 5 ). [0133] Embodiments have been described with reference to two differing illumination settings having differing spatial intensity distributions in the pupil or pupil plane 12 . The term “illumination setting” refers not only to the spatial intensity distribution but also to the spatial polarization distribution in the pupil. [0134] Using the at least two optical modules 28 , 29 , it is also possible to adjust a single spatial illumination setting with regard to the spatial intensity distribution in the pupil plane 12 , the illumination settings differing merely in terms of their spatial polarization distribution in the pupil plane 12 . Depending on the structures to be imaged, the second illumination setting can, for example, have a polarization distribution rotated through 90° in the pupil plane 12 relative to the polarization distribution of the first illumination setting in the pupil plane 12 . It is thus possible, by suitable activation of the two optical modules 28 , 29 , to control the proportional illumination thereof using a control unit, such as for example the computer 43 , so as to allow, for a single intensity illumination setting with which the reticle 19 is illuminated, various polarization states to be achieved during the illumination. [0135] This can be advantageous, for example, if manufacturing processes are to be transferred from development installations in development centres to production installations in factories for manufacturing microstructured components or chip factories and these differing installations, in particular the projection objectives thereof for imaging mask structures onto the wafer, differ in terms of their polarization transfer characteristics. In such a case, it can be advantageous if, for a single intensity illumination setting, the development of which has been found to be optimal for a specific chip structure, use of the two optical modules allows the polarization characteristic to be controlled, so the production installations operated therewith also image optimum chip structures onto the wafer. Another application of the change in polarization characteristic at a single intensity illumination setting is obtained on illumination of chips in a scanning process in which, although a single intensity illumination setting was selected for illuminating the entire chip, the chip structures in differing regions of the chip can be imaged with higher contrast by differing polarization. In this case, it can be desirable to vary the polarization characteristics during the scanning process. In addition, the spatial intensity distribution of the illumination settings (e.g., intensity illumination setting), generated by the at least two optical modules, can also be altered during the scanning process. [0136] A further aspect in the change in polarization characteristics at a single illumination setting can be obtained from what is known as polarization-induced birefringence. This is a material effect based on the fact that polarized irradiation of the material causes over time stress birefringence in the material through which the illumination light passes. Such material regions with illumination-induced stress birefringence form defect regions in the material. In order to prevent these material defects, circular or unpolarized light is, if possible, used. The present disclosure can allow the polarization characteristic to be altered at a single intensity illumination setting, thus allowing polarization-induced birefringence to be reduced, at least for the optical components following the coupling element. [0137] Based on the foregoing embodiments, it is also possible using the at least two optical modules 28 , 29 to generate any desired illumination settings having any desired polarization distributions in the pupil plane 12 . It is in this case also possible to change rapidly between the illumination settings having the corresponding polarization states—up to a plurality of changes within a light pulse. Furthermore, it is possible to allow slow changes of the illumination settings in synchronism with the scanning process and at the same time to alter the polarization distribution within the at least two optical modules 28 , 29 using appropriate polarization-influencing optical elements, such as for example a polarization rotation unit as described in WO 2006/040184 A2 or a rotatable λ/2 plate as disclosed, for example, in WO 2005/027207 A1, which are arranged in the modules 28 , 29 or in the beam direction after these modules, for example in time correlation with the scanning process. [0138] Polarization-influencing optical elements as presented, for example, in WO 2006/040184 A2 can allow relatively fast changes in the polarization characteristic within the two modules 28 , 29 . The disclosure therefore provides the flexibility to illuminate chip structures or combinations of differing chip structures of wafer partial regions, for example during the scanning process, with intensity illumination settings adapted to the requirements for imaging and/or spatial polarization distributions in the pupil plane of the projection exposure apparatus for imaging which is optimised with regard to contrast and resolution. For chip manufacturers, this can open up new possibilities for arranging differing chip structures on a wafer, as the disclosure allows combination of chip structures which, owing to the various requirements placed on the necessary illumination settings, may have been previously avoided on a single wafer or may have been imaged only with relatively high integration density. [0139] With the foregoing embodiments, it is equally possible to provide, using the at least two optical modules 28 , 29 , a single intensity illumination setting even with the same spatial polarization distribution, i.e. two illumination settings which are similar within predetermined tolerances, in the pupil plane 12 . This is, for example, advantageous if during the scanning process double exposure with two differing settings and/or differing polarization states would be inappropriate for specific partial regions of a chip, for the high-contrast imaging of chip structures into the partial region. [0140] A further potential advantage of operating the two optical modules 28 , 29 with identical illumination settings and identical spatial polarization distributions in the pupil plane 12 is that, on switching during the light pulse according to the switching-time example in FIG. 3 , the peak load or, on switching between the light pulses according to the switching-time example in FIG. 2 , the permanent load on the optical components in the two optical modules 28 , 29 is reduced compared to operation of an identical illumination setting with the same polarization distribution in a conventional illumination system or compared to operation of the illumination setting in merely one of the two optical modules 28 , 29 . [0141] FIGS. 18 to 29 specify examples of combinations of differing illumination settings in the pupil plane 12 with associated mask structures. The examples specified in FIGS. 18 , 19 , 22 , 23 , 26 and 27 are merely a small selection of the illumination settings achievable by the disclosure. [0142] The terms “sigma inner (inner σ)”, “sigma outer (outer σ)” and “polar width” will be used hereinafter for the purposes of characterization. The inner σ is in this case defined as the pupil radius in which 10% of the illumination light intensity is in the pupil. The outer σ is in this case defined as the pupil radius in which 90% of the illumination light intensity is in the pupil. The polar width is defined as the opening angle between radii which delimit a structure illuminated in the pupil plane and at which the intensity has fallen to 50% of the maximum intensity of this structure. [0143] FIG. 18 shows an illumination setting in the form of dipole illumination in the X-direction having a polar width of 35°, an inner σ of 0.8 and an outer σ of 0.99. FIG. 19 shows a further illumination setting in the form of a dipole illumination in the Y-direction having a polar width of 35°, an inner σ of 0.3 and an outer σ of 0.5. The illumination setting in FIG. 18 can in this case be provided by the module 28 and the illumination setting in FIG. 19 by the module 29 or vice versa. If these illumination settings are to be operated in a polarized manner, it is advantageous if the illumination setting in FIG. 18 is polarized linearly in the Y direction. The polarization direction of the illumination setting in FIG. 19 is in this case not crucial for the imaging contrast as owing to the maximum outer σ of 0.5 the light beams strike the wafer while still at moderate angles in contrast to the illumination setting in FIG. 18 . [0144] FIGS. 20 and 21 show exemplary mask structures that can be illuminated and imaged with good imaging quality during a scanning process by double exposure or change-over of the illumination settings in FIGS. 18 and 19 provided by the optical modules 28 , 29 . The mask structure in FIG. 20 is in the form of thick vertical lines having an extension in the Y direction of 50 nm wide and a 50 nm spacing between the lines in the X direction. The mask structure in FIG. 21 is in the form of horizontal and vertical lines having a width greater than 100 nm. In the latter case, the lines are said to be isolated. The simultaneous imaging of structures in FIGS. 20 and 21 is a typical application in which on a mask in one direction relatively low width structures and at the same time in the same direction or perpendicularly thereto relatively non-low width structures are to be transferred via illumination onto the wafer. Depending on whether on a mask the aforementioned thick and isolated lines from FIGS. 20 and 21 are formed adjacently to or set apart from one another, the double exposure or the change-over or a mixture of double exposure and change-over of the illumination settings in FIGS. 18 and 19 , correlated with the scanning process, will prove to be optimal for imaging the mask structures of FIGS. 20 and 21 . The illumination setting in FIG. 18 is suitable for the high-contrast imaging of a mask having exclusively thick lines corresponding to the mask structure in FIG. 20 and the illumination setting in FIG. 19 is suitable for high-contrast imaging of a mask having exclusively isolated lines corresponding to the mask structure in FIG. 21 . [0145] FIG. 22 shows an illumination setting in the form a quasar or quadrupole illumination having poles with 35° polar width along the diagonal between the X and Y direction with an inner σ of 0.8 and an outer σ of 0.99. FIG. 23 shows an illumination setting in the form of a conventional illumination with an outer σ of 0.3. The illumination setting in FIG. 22 can in this case be provided by the module 28 and the illumination setting in FIG. 23 by the module 29 or vice versa. If these illumination settings are to be operated in a polarized manner, it is advantageous if the illumination setting in FIG. 22 is linearly polarized tangentially to the optical axis. The foregoing remarks concerning the polarization direction of the illumination setting in FIG. 19 accordingly apply to the polarization direction of the illumination setting in FIG. 23 . [0146] FIGS. 24 and 25 show mask structures which are to be provided by double exposure or change-over of the illumination settings in FIGS. 22 and 23 during a scanning process. These structures are relatively high packing density ( FIG. 24 ) and relatively non-high packing density ( FIG. 25 ) contact holes having a width of, for example, 65 nm. Depending on whether on a mask the aforementioned high packing density contact holes and non-high packing density contact holes from FIGS. 24 and 25 are formed adjacent to or set apart from one another, the double exposure or change-over or a mixture of double exposure and change-over of the illumination settings in FIGS. 22 and 23 , correlated with the scanning process, will be found to be optimal for imaging the mask structures from FIGS. 24 and 25 . The illumination setting in FIG. 22 is suitable for the high contrast imaging of a mask having exclusively relatively high packing density contact holes corresponding to the mask structure of FIG. 24 and the illumination setting in FIG. 23 can be best suited for the high-contrast imaging of a mask having exclusively non-high packing density contact holes corresponding to the mask structure of FIG. 25 . [0147] FIG. 26 shows an illumination setting in the form of an X-dipole illumination having poles with 35° polar width in the X direction with an inner σ of 0.8 and an outer σ of 0.99. FIG. 27 shows an illumination setting in the form of a Y-dipole illumination having poles with 35° polar width in the Y direction with an inner σ of 0.8 and an outer σ of 0.99. The illumination setting in FIG. 26 can in this case be provided by the module 28 and the illumination setting in FIG. 27 by the module 29 or vice versa. If these illumination settings are to be operated in a polarized manner, it is advantageous if the illumination setting in FIG. 26 is polarized linearly in the Y direction and the illumination setting in FIG. 27 is polarized linearly in the X direction. [0148] FIGS. 28 , 29 show the two masks which are successively to be imaged onto the same wafer to be illuminated by double exposure with the illumination settings in FIGS. 26 and 27 during two scanning processes. These masks are thick horizontal ( FIG. 28 ) and vertical ( FIG. 29 ) structures having a width of, for example, 50 nm and a line spacing of, for example, 50 nm. In contrast to the foregoing examples, for imaging the two masks in FIGS. 28 , 29 there is carried out a double exposure in which there is carried out on the same wafer to be illuminated, in a first step, a scanning process with the mask in FIG. 28 and the illumination setting in FIG. 26 and, in a second step, a second scanning process with the mask in FIG. 29 and the illumination setting in FIG. 27 . Two different illuminations are thus carried out on the same wafer with the differing masks. This double exposure with the differing masks therefore differs from the double exposure or change-over in a single mask in which merely the illumination setting with which the mask is illuminated is changed. It is also possible in this case for the two separate masks to be arranged next to each other in the reticle or mask plane and to be moved in the scanning direction by component 23 for holding and manipulating the masks or reticles. In this case, there is no need for a complex change of masks between the two illuminations and the masks can be successively transferred onto the same wafer to be illuminated in a single scanning process instead of in two scanning processes carried out in succession. Owing to the high scanning speed of the component 23 , which is responsible for the high wafer throughput of the projection exposure apparatus, it is necessary to change the illumination settings for the two masks very rapidly during transfer of the masks in the one scanning process. In principle, it is not compulsory for the two separate masks to be arranged in the same plane. In principle, the two masks can also be arranged in various planes, the projection exposure apparatus being adapted during the change between the masks arranged in various planes by appropriate and optionally automatic adjustment of optical components. [0149] In all of the above-mentioned illumination settings in FIGS. 18 , 19 , 22 , 23 , 26 and 27 , the double or multiple exposure according to the disclosure of a mask with the two illumination settings in FIGS. 18 and 19 , 22 , 23 , 26 and 27 with switching times of up to 1 ns or the change-over according to the disclosure of the two settings allows precise monitoring and optimization of the light intensity within the two settings. This can allow for the scanning process with a mask structure in FIGS. 20 , 21 , 24 , 25 , 28 and 29 good (e.g., optimum) structures and structure widths to be achieved on the wafer to be illuminated. It is in this case also possible for the two zoom-axicon groups 11 , 31 of the two optical modules 28 , 29 to be controlled over a slower time scale during the scanning process in order to alter the inner and outer minimum or maximum illumination angles, defined by the two respectively utilized illumination settings. [0150] A further potential advantage of operating the at least two optical modules 28 , 29 with identical or differing illumination settings and with identical or differing polarization distributions in the pupil plane 12 is obtained on switching during the light pulse in accordance with the switching-time example in FIG. 3 if, within an optical module 28 or 29 , use is made of an optical component 80 which delays the partial light pulse of the module (see FIG. 17 ). The optical component 80 may, for example, consist of a correspondingly folded optical delay line, of at least two mirrors or of corresponding equivalents which allow the light propagation time to be extended. Switching during the light pulse in accordance with the switching-time example in FIG. 3 allows, as stated hereinbefore, a laser having an output with a repetition rate of 12 kHz to be produced from a laser having a repetition rate of, for example, 6 kHz. The optical component 80 in FIG. 17 then delays the partial light pulse of the illumination light in the optical module 29 in relation to the other partial light pulse of the illumination light in the other optical module 28 with regard to the light propagation time in such a way that, for example, the partial light pulses from the one module 28 are mutually time-shifted with respect to the partial light pulses from the other module in such a way that chronologically equidistant light pulses arrive on the reticle 19 to be illuminated. In this case, the light pulses L 1 , L 2 are time-delayed by the interval of adjacent laser pulses L at the location at which they were separated at the switching instant t s , so all the laser pulse parts L 1 , L 2 generated by the switching are at the same intervals from one another after the coupling element. Thus, for example, not only can a 6 kHz laser be split up to form a 12 kHz laser, the dose per time interval of the split 12 kHz laser can, for example, also be controlled so as substantially to correspond to the dose per time interval of a real 12 kHz laser. This is important for a scanning process with pulsed light sources, as it has to be ensured that each partial region of a chip is given the same dose of light during the scanning process. If, as mentioned hereinbefore, the two modules 28 , 29 are operated proportionally, i.e. with, in their dose, differing partial light pulses in the period of time and/or with varying intensity, a chronologically non-equidistant pulse sequence of the light pulses arriving on the reticle 19 from the two modules 28 , 29 may be beneficial with regard to the dose. [0151] It should be noted that the above-mentioned polarization setting within the two optical modules 28 , 29 or thereafter is not only beneficial with regard to the adjustment of the spatial polarization distribution in the pupil plane 12 for the respective illumination settings, as for example in FIG. 18 , 19 , 22 , 23 , 26 or 27 ; it is also beneficial to preserve a certain polarization state which is varied by the two optical modules 28 , 29 themselves, the subsequent lens system, the reticle 19 , the projection objective 20 and/or by a photoresist layer of the wafer 24 to be illuminated. It is thus possible to provide on the wafer 24 the polarization state respectively required for high-contrast imaging even if the polarization state changes in the light path from the polarization-influencing optical elements to the wafer 24 . This preservation of a spatial polarization distribution may also prove beneficial only during operation of a projection exposure apparatus if, owing to slow changes in the optical characteristics of the optical elements of the illumination system 5 , the projection objective 20 and the reticle 19 , these optical elements alter the polarization state of the light passing therethrough. Slow changes of this type may, for example, be brought about by thermal drifts. [0152] As an alternative to switching the polarization using a Pockels cell 8 ; 39 or a Kerr cell, use may also be made of a magneto-optic switch based on the Faraday effect. [0153] As an alternative to the aforementioned switching or decoupling using the light wavelength as the exchangeable light characteristic, Raman cells, as described in U.S. Pat. No. 4,458,994, or Bragg cells, as described in U.S. Pat. No. 5,453,814, may be used. U.S. Pat. No. 4,458,994 and U.S. Pat. No. 5,453,814 are hereby incorporated by reference. Use may be made for this purpose of a photoelastic modulator (PEM) such as is described, for example, in US 2004/0262500 A1, which is hereby incorporated by reference. [0154] As an alternative to the aforementioned possible switching or decoupling elements, use may also be made of combinations of the aforementioned options, especially combinations in which at least one component operates of the basis of an electro-optical or magneto-optical principle. [0155] Other embodiments are in the claims.

Optics, such as, for example, microlithographic projection exposure apparatus illumination optics, as well as related systems, methods, components and devices are disclosed.

CROSS-REFERENCE TO RELATED PATENT APPLICATION [0001] The present regular U.S. patent application relies upon and claims the benefit of priority from U.S. provisional patent application No. 61/736,471 filed on Dec. 12, 2012, the entire disclosure of which is incorporated by reference herein. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The described embodiments relate in general to methods and systems for providing recommendations to Brand Marketers who are promoting Brands and, more particularly, to recommending Marketing Actions, which would increase number of customers of the Brand brought through available Media Channels. [0004] 2. Description of the Related Art [0005] Promoting a Brand includes executing Marketing Actions across Media Channels. In accordance with conventional technology, it is a costly trial and error process as human work is required to identify and execute series of Marketing Actions. Therefore, there is a need for systems and methods that would automate this process and produce reliable recommendations to increase the number of Customers of the Brand through the Media Channels. [0006] Certain terms of art will be are used in the present patent specification in accordance with the respective meanings specified in the below table. [0000] Term Explanation Brand Brand is the object of promotion Brand Marketer Person who promotes the Brand Brand Taxonomy Industry Classification of the Brand Potential Person interested in purchasing from the Brand Customer Marketing Action Action taken by Brand Marketer to promote the Brand Media Channel, Specific way to represent the Brand and communicate Brand Media with the audience. Channel Brand Feature Property of the Brand Brand Metrics Set of measured values related to the activity of Potential Customers of the Brand Brand State Set of measured values related to the Brand representation in Media Channels Recommendation Changes in Brand Metrics related to Potential Effect Customers caused by Marketing Action. API Application Programming Interface Brand Similarity Degree to which two Brands are similar Brand Model Attributes of the Brand Parameters Target Audience People or organizations targeted by Marketing Activity of the Brand Marketer SUMMARY OF THE INVENTION [0007] One or more of the described embodiments are generally directed to computerized methods and systems that automatically recommend marketing activity for promoting a given Brand across marketing channels. [0008] In accordance with one aspect of the embodiments described herein, a recommender system is provided. In one or more embodiments, the recommender system is a computerized system, which accumulates and analyzes the information about Marketing Actions for promoting Brands as well as information about the subsequent Brand performance within Media Channels. The Channels include, but are not limited to Web, Blogs, Social Networks, Search Engines, Contextual Ad Networks, Email Campaigns, and other promotional activities. More Media Channels can be added into the recommender system. This recommender system enables the Marketers to obtain custom advice for a given Brand as to what should be the next most effective Marketing Actions to promote the Brand. [0009] The described embodiments provide methods and algorithms of the recommender system for suggesting most effective Marketing Actions for promoting the Brand. The recommender system contains an extendable set of recommendations (possible Marketing Actions) within Media Channels. The recommender system predicts the effect of each Marketing Action upon the Target Audience of the Brand through applying machine learning algorithm. The training sets are obtained through measuring the Marketing Actions and the changes in the Brand Metrics, caused by the Marketing Actions. Marketing Actions are determined through analyzing the difference in subsequent snapshots of the Brand State. The Effect of the Marketing Action is determined through measuring Brand Metrics after the Marketing Action. The effect of the Marketing Action is predicted by fitting the collected data into the developed model and using Collaborative Filtering. [0010] In accordance with another aspect of the embodiments described herein, methods and algorithms are provided to determine the applicability of marketing knowledge accumulated by one Brand to another Brand. The applicability of marketing knowledge is determined through calculating the Brand Similarity as well as comparison of Brand Model Parameters between two Brands. [0011] In accordance with yet another aspect of the embodiments described herein, there is provided a computerized system for providing recommendations in connection with a brand, the computerized system comprising at least one processing unit, a data storage unit and a memory unit, the at least one processing unit executing instructions including: a user event collector module for collecting user events information associated with potential customers in connection with the brand in each of a plurality of media channels and storing the collected user events information in the data storage unit; a brand metrics crawler for measuring metrics of the brand in each of the plurality of media channels and storing the measured brand metrics in the data storage unit; a brand state crawler for collecting information on a marketing activity in connection with the brand in each of the plurality of media channels and storing the collected marketing activity information in the data storage unit; and a recommender module for analyzing the collected user events information, the measured brand metrics and the collected marketing activity information to obtain a brand feedback information, for storing the brand feedback information in the data storage unit and for providing a plurality of recommendations based on the brand feedback information. [0012] In one or more embodiments, the plurality of channels comprise at least one channel selected from a group of web, blogs, social networks, search engines, contextual ad networks, and email campaigns. [0013] In one or more embodiments, the data storage unit further stores a user events aggregation module for aggregating the collected user events information and storing the aggregated user events information in a database system. [0014] In one or more embodiments, the data storage unit further stores a measured brand metrics aggregation module for aggregating the measured brand metrics and storing the aggregated measured brand metrics in a database system. [0015] In one or more embodiments, the data storage unit further stores a marketing activity information aggregation module for aggregating the collected marketing activity information and storing the aggregated marketing activity information in a database system. [0016] In one or more embodiments, the at least one processing unit further executes a configuration module for receiving information on the plurality of media channels. [0017] In one or more embodiments, the at least one processing unit further executes a user interface module for providing the plurality of recommendations to a user. [0018] In one or more embodiments, the plurality of recommendations comprise an ordered list of marketing actions associated with the plurality of media channels. [0019] In one or more embodiments, the recommender module is configured to sort the ordered list of marketing actions based on a predicted marketing effect. [0020] In one or more embodiments, the recommender module is configured to calculate a similarity between two brands and to obtain brand similarity information. [0021] In one or more embodiments, the recommender module is configured to accumulate marketing experience for the brand through recording subsequent snapshots of brand model parameters and calculated effect of each change of brand content associated with the brand. [0022] In one or more embodiments, the recommender module is configured to apply the marketing experience accumulated for a first brand to a second brand based on the brand model parameters, the brand similarity information, and the calculated change effect. [0023] In one or more embodiments, the recommender module is configured to predict an effect of a change of a brand content based on the accumulated marketing experience and the brand similarity information. [0024] In accordance with yet another aspect of the embodiments described herein, there is provided a computer-implemented method for providing recommendations in connection with a brand, the computer-implemented method being performed in connection with a computerized system comprising at least one processing unit, a data storage unit and a memory unit, the method involving: collecting user events information associated with potential customers in connection with the brand in each of a plurality of media channels and storing the collected user events information in the data storage unit; measuring metrics of the brand in each of the plurality of media channels and storing the measured brand metrics in the data storage unit; collecting information on a marketing activity in connection with the brand in each of the plurality of media channels and storing the collected marketing activity information in the data storage unit; analyzing the collected user events information, the measured brand metrics and the collected marketing activity information to obtain a brand feedback information; storing the brand feedback information in the data storage unit; and providing a plurality of recommendations based on the brand feedback information. [0025] In one or more embodiments, the plurality of channels comprise at least one channel selected from a group of web, blogs, social networks, search engines, contextual ad networks, and email campaigns. [0026] In one or more embodiments, the data storage unit further stores a user events aggregation module for aggregating the collected user events information and storing the aggregated user events information in a database system. [0027] In one or more embodiments, the data storage unit further stores a measured brand metrics aggregation module for aggregating the measured brand metrics and storing the aggregated measured brand metrics in a database system. [0028] In one or more embodiments, the data storage unit further stores a marketing activity information aggregation module for aggregating the collected marketing activity information and storing the aggregated marketing activity information in a database system. [0029] In one or more embodiments, the method further involves receiving information on the plurality of media channels. [0030] In one or more embodiments, the plurality of recommendations comprise an ordered list of marketing actions associated with the plurality of media channels. [0031] In one or more embodiments, the method further involves sorting the ordered list of marketing actions based on a predicted marketing effect. [0032] In one or more embodiments, the method further involves calculating a similarity between two brands and to obtain brand similarity information. [0033] In one or more embodiments, the method further involves accumulating marketing experience for the brand through recording subsequent snapshots of brand model parameters and calculated effect of each change of brand content associated with the brand. [0034] In one or more embodiments, the method further involves applying the marketing experience accumulated for a first brand to a second brand based on the brand model parameters, the brand similarity information, and the calculated change effect. [0035] In one or more embodiments, the method further involves predicting an effect of a change of a brand content based on the accumulated marketing experience and the brand similarity information. [0036] In accordance with a further aspect of the embodiments described herein, there is provided a non-transitory computer-readable medium embodying a set of computer-executable instructions, which, when executed in connection with a computerized system comprising at least one processing unit, a data storage unit and a memory unit, cause the computerized system to perform a computer-implemented method for providing recommendations in connection with a brand, the method involving: collecting user events information associated with potential customers in connection with the brand in each of a plurality of media channels and storing the collected user events information in the data storage unit; measuring metrics of the brand in each of the plurality of media channels and storing the measured brand metrics in the data storage unit; collecting information on a marketing activity in connection with the brand in each of the plurality of media channels and storing the collected marketing activity information in the data storage unit; analyzing the collected user events information, the measured brand metrics and the collected marketing activity information to obtain a brand feedback information; storing the brand feedback information in the data storage unit; and providing a plurality of recommendations based on the brand feedback information. [0037] In one or more embodiments, the plurality of channels comprise at least one channel selected from a group of web, blogs, social networks, search engines, contextual ad networks, and email campaigns. [0038] In one or more embodiments, the data storage unit further stores a user events aggregation module for aggregating the collected user events information and storing the aggregated user events information in a database system. [0039] In one or more embodiments, the data storage unit further stores a measured brand metrics aggregation module for aggregating the measured brand metrics and storing the aggregated measured brand metrics in a database system. [0040] In one or more embodiments, the data storage unit further stores a marketing activity information aggregation module for aggregating the collected marketing activity information and storing the aggregated marketing activity information in a database system. [0041] In one or more embodiments, the method further involves receiving information on the plurality of media channels. [0042] In one or more embodiments, the plurality of recommendations comprise an ordered list of marketing actions associated with the plurality of media channels. [0043] In one or more embodiments, the method further involves sorting the ordered list of marketing actions based on a predicted marketing effect. [0044] In one or more embodiments, the method further involves calculating a similarity between two brands and to obtain brand similarity information. [0045] In one or more embodiments, the method further involves accumulating marketing experience for the brand through recording subsequent snapshots of brand model parameters and calculated effect of each change of brand content associated with the brand. [0046] In one or more embodiments, the method further involves applying the marketing experience accumulated for a first brand to a second brand based on the brand model parameters, the brand similarity information, and the calculated change effect. [0047] In one or more embodiments, the method further involves predicting an effect of a change of a brand content based on the accumulated marketing experience and the brand similarity information. [0048] Additional aspects related to the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Aspects of the invention may be realized and attained by means of the elements and combinations of various elements and aspects particularly pointed out in the following detailed description and the appended claims. [0049] It is to be understood that both the foregoing and the following descriptions are exemplary and explanatory only and are not intended to limit the claimed invention or application thereof in any manner whatsoever. BRIEF DESCRIPTION OF THE DRAWINGS [0050] The accompanying drawings, which are incorporated in and constitute a part of this specification exemplify the embodiments of the present invention and, together with the description, serve to explain and illustrate principles of the inventive technique. Specifically: [0051] FIG. 1 illustrates an embodiment of logical structure suitable for providing recommendations to marketers for purpose of increasing the exposure of the Brand through available media channels. [0052] FIG. 2 illustrates the use case scenario of the Recommender System as a standalone web service. [0053] FIG. 3 illustrates the use case scenario of the Recommender System as a component of the marketing solution. [0054] FIG. 4 illustrates an embodiment of process for registering the brand in the Recommender System. [0055] FIG. 5 illustrates an embodiment of the Recommender System data flow aspect. [0056] FIG. 6 illustrates an embodiment of the Recommendation Effect Estimation Sub-System data flow aspect. [0057] FIG. 7 illustrates an embodiment of process for generating recommendations based on the estimated recommendation effect. [0058] FIG. 8 illustrates an embodiment of the Brand Media Channel Traffic Model. [0059] FIG. 9 illustrates examples of models of the Recommendation Effect over time. [0060] FIG. 10 illustrates an embodiment of process for constructing the Channel Snapshot suitable for analysis and effect estimation. [0061] FIG. 11 illustrates an embodiment of process for estimating the effect of recommendations for target Brand. [0062] FIG. 12 illustrates an embodiment of process for computing similarity for two Brands. [0063] FIG. 13 illustrates an embodiment of hardware for implementing the Recommender System. DETAILED DESCRIPTION [0064] In the following detailed description, reference is made to the accompanying drawing(s), in which identical functional elements are designated with like numerals. The aforementioned accompanying drawings show by way of illustration, and not by way of limitation, specific embodiments and implementations consistent with principles of the present invention. These implementations are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other implementations may be utilized and that structural changes and/or substitutions of various elements may be made without departing from the scope and spirit of present invention. The following detailed description is, therefore, not to be construed in a limited sense. Additionally, the various embodiments of the invention as described may be implemented in the form of software running on a general purpose computer, in the form of a specialized hardware, or combination of software and hardware. [0065] In accordance with one aspect of the embodiments described herein, there is provided a recommender system for facilitating various marketing activities, which will be described below in detail with reference to the attached drawings. [0066] FIG. 1 illustrates an embodiment of logical structure 100 of a recommender system configured to generate marketing recommendations. The logical structure 100 describes a Recommender System 101 . The Recommender System 101 gets setup information about the observable media channels 106 , 112 , and 117 either through Brand Admin Web App 102 or programming API 107 . The Recommender System 101 holds corresponding data structures in its database storage 108 . [0067] In one or more embodiments, a Brand Metrics Crawler 111 is responsible for measuring the brand metrics for each channel 112 and storing the data in Brand Metrics Data Store 110 . The Brand Metrics may include information describing Channel State, fully or partially. They may include, but not limited to, website meta-information, page layouts, references, social account state, video channel keywords, and more. Brand Metrics Aggregation Task 109 aggregates the data and stores the data in the database 108 . Aggregated data produced by the aggregation task 109 is used for reporting by the Brand Admin Web application 102 as well as by the Recommendation Service 113 . [0068] In one or more embodiments, a Brand State Crawler 116 is responsible for collecting information related to the marketing activity in each channel through scanning Brand Media Channels 117 . The detected marketing activities (changes to Brand State) are stored in the Brand State Data Store 115 . The Brand State may include any information describing the marketing activity implemented by the Brand Marketer within media channels registered with the Recommender System 101 . The Brand State may include, but not limited to, social channel content changes, posts, video channel uploads, and so on. For reporting and processing purpose the Brand State data is aggregated and placed into the database 108 by the aggregation task 114 . [0069] In one or more embodiments, a User Events collector 105 registers events caused by Potential Customers which occur in Brand Media Channels 106 . User Events include clicks, page loads, scrolling events, and more. User Events are stored in the User Events Data Store 104 . User Events are further aggregated by the aggregation task 103 and are stored in the database 108 . [0070] In one or more embodiments, a recommendation service 113 is responsible for processing the aggregated channel feedback in Recommender System database 108 and for generating output recommendations. The Recommendation Service may use multiple recommendation effect models, optimization and personalization modules as needed. [0071] FIG. 2 illustrates the use case scenario of the Recommender System as a standalone application. As described in the diagram 200 , the Recommender System 204 exposes the public interface through Brand Administrator Web Application 205 . [0072] In one or more embodiments, a Marketer 201 accesses the Brand Administrator Web Application 205 via the Network 203 to register the Brand and to set up the Media Channels 208 , which the Marketer 201 accesses via Network 202 . The Marketer 201 may use information from the Recommender System 204 , specifically obtained by the Channel Crawlers 206 accessing the Media Channels 208 via Network 207 , in order to set up the Media Channels 208 . After setting up the Recommender System 204 and the Media Channels 208 , the Recommender System 204 starts generating recommendations which become available to the Marketer user 201 through the Brand Admin Web App 205 . [0073] FIG. 3 illustrates the use case scenario of the Recommender System 307 as the component of an online marketing platform. Part of the diagram 300 describes a process similar to the use case described in the diagram 200 . The Marketer 301 accesses the Brand Administrator Web Application 306 via Network 304 . The Marketer 301 sets up the Media Channels 312 , which the Marketer 301 accesses via Network 303 . The Marketer 301 may use the information from the Channel Crawlers 310 component of the Recommender System 307 , which access Media Channels 312 via Network 311 . In contrast to diagram 200 , in the use case depicted in diagram 300 the Online Marketing Application 305 is connected directly to the Recommender System 307 . The Recommender System 307 exposes a public API 309 for Online Marketing Applications 305 to consume via Network 308 . The recommendations generated by the Recommender System 307 are extracted by the Online Marketing Application 305 and are presented to the Marketer 301 who accesses the Online Marketing Application 305 via Network 302 . [0074] FIG. 4 illustrates an embodiment of process for registering the brand in the online marketing system providing recommendations for increasing traffic of target media channels 400 . The process is activating upon reception of a Request for Registering a Brand 401 . Subsequently during the step 402 the process of Brand Setup is performed, during which a series of the information describing the Brand is entered into the Database. Upon completion of the step 402 , the Channel Setup Process 403 is started. The Media Channels that can be enabled during the Channel Setup Process 403 include, but are not limited to Website, Blog, Social Networks, Online Ad Networks, Email Campaigns, and other promotional campaigns. There is no limit on number of Media Channels used by the system. The features of selected Media Channels are configured during the Brand Feature Setup Process 404 . Setting up Brand Features is necessary for calculations of the Brand Similarity. Brand Features include parameters such as Brand Taxonomy, target audience demographics, geography, and more. [0075] FIG. 5 illustrates an embodiment of the recommender system in data flow aspect. The Media Channels 501 , 505 , 509 serve as the sources of three types of data used in the recommendation generation and analysis: User Event Messages 502 , Channel Metrics Data 506 , and Brand State Data 510 . User Event Message data 502 is stored in the User Event Data Store 503 . Channel Metrics Data 506 is stored in the Brand Metrics Data Store 507 . Brand State Data 510 is stored in the Brand State Data Store 511 , All data 504 , 508 , 512 is passed from the respective Data Stores 503 , 507 , 511 for aggregation by the Analysis and Data Aggregation process 513 . The result of the work of the Analysis and Data Aggregation process is the Brand State 518 , which is stored in the Recommender System Database 517 . [0076] In one or more embodiments, a Recommendation Generation process 514 iterates over all possible Brand Actions 516 and based on the Brand State 518 stored in the Recommender System Database 517 produces Brand Recommendations 515 , which are passed to and stored in the Recommender System Database 517 . The Recommender System User Interface (UI) for Viewing Recommendations 520 accesses the Recommender System Database 517 , and extracts from it the Brand Recommendations 519 which it then displays. [0077] FIG. 6 illustrates an embodiment, in more detail, of the information exchange between the Recommender System Database 517 and the Recommendation Generation process 514 from FIG. 5 . In FIG. 6 , the Recommender System Database 610 provides several services for the Recommendation Estimation Process 617 , and, in turn, receives Estimated Recommendation Effects Data for the Brand 618 from the Recommendation Estimation Process 617 . [0078] In one or more embodiments, an information about the Brand State and the resulting effect (expressed as the media channel traffic) is aggregated by the Period Snapshot Construction process 603 , producing the Traffic Period Snapshots 604 , stored in the Brand Snapshots Data Store 606 . From the Traffic Period Snapshots, Brand Trends for a given Brand 608 are constructed. Additionally, the Period Snapshot Construction process 603 extracts the Brand Activity on Media Channels data 605 from the Recommender System database 610 using the traffic segments description 602 obtained from the segmentation data store 601 . [0079] In one or more embodiments, all brand snapshots are stored in the Brand Snapshots Data Store 606 grouped by brand trends. The Trends of each brand 608 are analyzed by the Brand Analysis process 609 in order to obtain the Brand Model Parameters 614 . Brand Model Parameters 614 are the characteristics of the Brand, determining its perception by the Effect Model. It allows the Recommender System to use the marketing experience of one Brand in preparing recommendations for other Brands, possibly with different Brand Model Parameters. [0080] In one or more embodiments, in parallel to establishing the Brand Model Parameters 614 for each Brand, a second sub-process does the pair wise similarity comparisons for Brands. The Brand Comparison process 612 uses the Brand Descriptions 611 stored in the Recommender System Database 610 to produce Brand Similarity Data (Brand Similarity Scores) 613 for each pair of Brands. (see FIG. 12 for an embodiment of the Brand Comparison process 612 in more detail). The Brand Similarity data 613 and the Brand Model Parameters data 614 are used to tune the Recommendation Effect Model 616 and stored in the Recommendations Effects Model Store 615 . The Recommendation Estimation Process 617 receives the Recommendation Effects Model 616 tuned for a specific Brand based on the Brand Model Parameters 614 and the Brand Similarity data 613 comparing the Brand to all other Brands. Additionally, the Recommendation Estimation Process receives from the Period Snapshots Data Store 606 information about the Trends of all Brands in the system 607 . The resulting Estimated Effect information of a Brand Action on the Brand 618 may be computed on demand and transferred to the user, but the most effective implementation stores the results first in the Recommender System Database 610 . [0081] FIG. 7 illustrates an embodiment of process for generating recommendations 700 for the Brand 702 based on the estimated recommendation effect. The process 700 begins with the Retrieval of the Aggregated Brand State 704 for Brand 702 . A cyclic process 705 of retrieving, one by one, of all possible recommendations from the Recommendation Base 701 and computing their effects on the current Brand State. During every iteration of the cyclic process 705 , the next recommendation from the Recommendation Base 701 is retrieved by the Recommendation Retrieval process 706 . Once the Recommendation Retrieval Process 706 retrieves the next recommendation R from the Recommendation Base 701 , an applicability test 708 of the Recommendation R to the current state of S (constructed by the Retrieval of the Aggregated Brand State process 704 ) of the Brand 702 . This process may access any part of the complex brand state to check the conditions of applying the recommendation. This process discovers all the parts of the brand state, where the recommendation is applicable. If the recommendation is not applicable at all, it is skipped. [0082] In one or more embodiments, if the Recommendation R is not applicable to the State S of the Brand, the cyclic process 705 proceeds to retrieve the next recommendation from the Recommendation Base 701 . [0083] In one or more embodiments, if the Recommendation R is applicable to the State S of the Brand, the Effect Estimation process 710 is run. This process may use the time horizon 703 to skip possible old data in the brand trends (see FIG. 11 for an embodiment of the Effect Estimation process 710 in detail). [0084] In one or more embodiments, once the Effect Estimation process 710 produces estimated effects of applying the Recommendation R to the Brand 702 in its State S, this information is added to the Recommendation List, but Recommendation List Construction process 711 . This process is responsible for generating the final recommendation and it generates a recommendation for every applicable case within the Brand. All recommendations are finally added into the list. [0085] In one or more embodiments, when, the cyclic process 705 exhausts all recommendations from the Recommendation Base 701 , the final part of the process 700 begins. The Recommendation List built by the Recommendation List Construction process 711 is sorted by the estimated effect by the Recommendation List Sorter process 707 . The Output Recommendations process 709 outputs top recommendations from the sorted Recommendation List. The number of output recommendations may be limited for usability reasons. [0086] FIG. 8 illustrates an embodiment of the Brands Media Channel Traffic Model 800 , used within the channel snapshotting process and within the channel trend registration process. The particular embodiment of the model is represented by means of two plots. Both graphs share the horizontal coordinate axis 803 and 806 representing Time. Time=0, in both cases is the time when the Brand started its presence on a specific Media Channel. The first graph depicts a possible curve of the Media Channel of the Brand in absolute values. The vertical axis for this graph 802 measures the absolute amount of Channel Traffic. The Channel Traffic curve 806 measures the total cumulative amount of Channel Traffic experienced by the Brand Media Channel at each moment of time. It must be a non-decreasing curve, but may have any other shape. The second plot of channel traffic measures Channel Traffic Intensity 804 . It is shown in the model 800 with the time axis 806 set synchronous with the time axis 803 of the Cumulative Channel Traffic plot ( 803 , 801 , 806 ). The traffic of the channel is usually measured at some registration moments R 1 , . . . Rk 807 . The last registration moment usually matches the current time (shown on the figure), but it is not necessary. At some moments the channel has applied some recommendations, but these moments do not necessarily match the registration moments 807 . The registration moments divide all the channel observation time into several intervals. The bar chart 805 shows the channel traffic intensity, i.e., Channel Traffic per Unit of Time, for each time interval. Each channel traffic interval is represented by the corresponding snapshot. The set of the snapshots represents entire media channel trend or brand trend. [0087] FIG. 9 illustrates the embodiments of some examples of the recommendation effect functions suitable for building recommendation effect models as disclosed in this invention. The effect template function may be set in two forms—in the cumulative form 901 or in the form of the effect intensity 907 . For each effect template function specified in the cumulative effect form, there exists an exact representation of this function in the effect intensity form, and vice versa. This is illustrated in the plots 901 and 902 using the pairs of functions with the same line structure used for depiction. As such, the curve 902 and the curve 909 represent the same recommendation effect function described in the cumulative effect and effect intensity forms respectively. The curve 904 and the curve 911 describe the same recommendation effect function in the cumulative effect and effect intensity forms respectively. The curves 903 and 910 describe the same recommendation effect function in the cumulative effect and effect intensity forms respectively. [0088] In one or more embodiments, the recommendation effect template function is the model of the average expected channel traffic change in response to a use of a single specific recommendation on this channel. That is why chart 900 is organized the same way as the channel traffic model 800 . Time axes of booth plots 901 and 907 are synchronous. Time points 906 and 913 are the moments when the recommendation was implemented on the channel. [0089] Chart 900 contains examples of three different recommendation effect templates. The solid curves 909 and 902 are typical for some effect which reaches the maximum 908 of channel traffic intensity and never fades. The example of corresponding recommendation may be adding keywords to the web page for search engine optimization. The dash-dotted curves 904 and 911 are typical for some effect which rapidly fades after it reaches its maximum 908 (depicted here to be the same as the maximum of the curve 909 for illustrative purposes only. Typically, each curve will have its own maximum traffic intensity that is not correlated with the maximum traffic intensity reachable by other recommendation effect curves) until the complete disappearance of traffic attributed as the effect of this recommendation. The example of corresponding recommendation may be posting a Twitter message. The cumulative effect of such recommendation is limited to some finite value 905 . The dashed curves 910 and 903 are typical of some in-between behavior, which has a non-zero 912 residual effect of the recommendation, i.e., which represents a situation where, upon reaching the maximum traffic intensity 908 the traffic intensity decreases until it reaches a stable value 912 , which is referred in this document as the residual traffic intensity of a recommendation. Adding the new article to the blog may be an example of such recommendation. The effect templates depicted in chart 900 may take different times to reach their maximum and their stable (for curves 911 and 910 ) values. Such variations are not depicted. Other shapes of the effect templates (not shown) are also possible, for example, to model some dynamic or cyclic behaviors, such as seasonal effects. [0090] In one or more embodiments, the suitable ways of building the recommendation effect model from template functions may include, but are not limited to scaling, time-shifting, time-stretching, value offset, and its combination with other templates. The embodiments of specific recommendation effect models may be described by a set of parameters. Examples of such parameters may include the value of the residual traffic, the time to reach peak effect intensity, the value of the peak effect intensity. Other effect model templates can be described using parameters not mentioned here. The parameters mentioned above are given for illustrative purposes only and do not construe an exhaustive list. [0091] FIG. 10 illustrates an embodiment of process for constructing a channel snapshot suitable for analysis and estimation of the recommendation effect. The resulting snapshot aggregates the Segmented Channel Traffic Data 1003 and the Brand State 1002 for the Given Period 1004 . [0092] In one or more embodiments, the process of this aggregation begins with the Snapshot Initialization 1005 . The Snapshot Initialization aggregates the channel traffic in the snapshot for the period 1004 . The Snapshot Initialization 1005 adds no information about recommendation effects, used in the period. At the end of the Snapshot Initialization 1005 , the snapshot PS is set to a state, where all the channel traffic of the given period is modeled as the result of some default channel actions, but not as a result of using recommendations. The main part of the Period Snapshot Estimation process 1000 occurs within the cyclic process 1007 which iterates over a list of all recommendation actions taken by the Brand and contained in the Brand State 1002 . For as long as additional recommendations need to be processed, the Recommendation Retrieval process 1006 retrieves the next unprocessed recommendation R from the Brand State S 1002 . On the next step, the Recommendation Effect Template Retrieval Process 1009 retrieves the recommendation effect template EF for R from the Recommendation Effect Template Base 1001 (see FIG. 9 for more information on the structure of the recommendation effect templates). The Recommendation Effect Template Base 1001 stores a collection of recommendation effect templates for each recommendation available to the Recommender System. Using the recommendation effect template EF and Brand State S 1002 , the Recommendation Effect Model Creation process 1010 produces the effect model for the recommendation R. The produced effect model is incorporated into the Period Snapshot model by the Effect Model Incorporation process 1011 . Upon consideration of all recommendations, at the Output Phase 1008 , the Period Snapshot is set to state, where all the channel traffic for the given period is expressed as the result of the application of observed recommendations. [0093] In one or more embodiments, the period snapshot has a formal expression. The suitable form of the expression matches the following criteria: the snapshot, combined with some effect estimations for all recommendations, brand model parameters estimation and the estimated default effect of the channel determines the difference between the actual channel traffic and the expected channel traffic for the period of the snapshot. [0094] FIG. 11 illustrates an embodiment of the process 1100 for estimating the effects of all recommendations for the target Brand 1103 . This process allows effect estimation even for Brands with short observation period or inaccurately collected Brand State. The process 1100 overcomes pointed issues through sharing the experience of other Brands 1102 with the target Brand 1103 . The experience of other Brands is provided via Brand Trends 1101 . [0095] In one or more embodiments, the process 1100 includes three phases: data preparation 1105 , 1106 , implementation of effects model 1107 , 1108 , 1109 , 1110 , 1111 , 1112 , 1113 , 1114 , and fitting the data into the model 1115 , 1116 , 1117 . [0096] In one or more embodiments, the preparation phase starts the Brand Similarity Values Retrieval process 1105 in which Brand similarity values are retrieved for the target brand 1103 for all brands 1102 . Following that, Recommendation Effects Model Initialization 1106 takes place, in which the recommendation effects model is initialized. This model includes all recommendation effects, included in the Brand Trends. [0097] In one or more embodiments, the model implementation phase is controlled by the cyclic process 1107 , which iterates over the list of Brands 1102 . The Brand Retrieval Process 1108 retrieves the next Brand Bi to be considered and the similarity value Si=similarity (TB, Bi): the similarity between the Target Brand TB 1103 and the retrieved Brand Bi. Only Brands sufficiently similar to the Target Brand participate in the effects model. The Similarity Score Filter 1109 filters out all non-similar brands. On the next step, the Brand Model Parameters Retrieval process 1110 retrieves the Brand Model Parameters BP for the Brand Bi. The Parameters Filter 1111 identifies brands with Model Parameters that are sufficiently high and influential for the later calculations. The two Filters 1109 and 1111 increase the performance and stability of the process 1100 . [0098] In one or more embodiments, Brands that pass the Filters 1109 and 1111 are called suitable. For each suitable Brand the Trend Retrieval process 1112 retrieves its trends. The Time Horizon 1104 is used as the time-filtering criteria. Time filtering process is subject to customization. [0099] In one or more embodiments, the Partial Recommendation Construction process 1113 computes the effects model from the Brand Trend and Brand Model Parameters. The suitable partial model matches the following criteria: the partial model combined with some effect estimations (for all recommendations) determines the difference between the actual channel traffic and the expected channel traffic for all periods of the brand trend (and thus all periods of the model). [0100] In one or more embodiments, the recommendations effects model created by the Partial Recommendation Construction process 1113 is called partial because in most cases this model is not able to unambiguously determine the desired optimal effects. To prevent ambiguity of the solution, all different partial models are incorporated in the overall recommendation effects model by the Recommendation Model Construction process 1114 . This process is allowed to use additional heuristics and processes to optimize the recommendation effects model. [0101] In one or more embodiments, the model fit phase of the process 1100 starts when the cyclic process 1107 completes, i.e., when all Brands have been considered by the cycle 1107 , 1108 , 1109 , 1110 , 1111 , 1112 , 1113 , 1114 . The Recommendation Effects Model EM computed on the final iteration of the Recommendation Model Construction process 1114 is passed to the Best Fit Effect Vector Construction process 1115 . The Best Fit Effect Vector Construction process 1115 computes the recommendation effects vector with best fit for all the conditions of the constructed model. Embodiments of some implementations (not depicted) may allow the Best Fit Effect Vector Constructions process 1115 to gracefully fail if the model is badly conditioned. The embodiment depicted in the process 1100 makes the Best Fit Effect Vector Construction process 1115 a process that always returns a result. The best fit effect vector EV computed by the Best Fit Effect Vector Construction process 1115 is transformed by the Effect Vector tuning process 1117 which is immediately preceded by the Target Brand Model Parameters retrieval process 1116 which retrieves the Brand Model Parameters for the Target Brand. The tuned effect vector produced by the Effect Vector tuning process 1117 is then passed to the Output process 1118 , which outputs the vector. [0102] FIG. 12 illustrates an embodiment of process for computing similarity between a pair of Brands: the Source Brand 1202 and the Target Brand 1203 . The comparison process uses the Brand Feature Set 1201 which describes every brand. The Brand Feature Set 1201 may include, but is not limited to, Brand Taxonomy, brand keywords, brand geographical location, brand target marketing segment, brand channels structure. Given a Brand, every Brand Feature from the Brand Feature Set 1201 for the Brand is represented by a numeric value. Additionally, an importance of each Brand feature is specified by a Brand Feature Weight, which is a non-negative numeric value. The Brand Similarity computation 1200 starts with the Similarity Value Initialization 1204 . The computation 1200 is driven by the cyclic process 1206 which iterates over the list of brand features from the Brand Feature Set 1201 . Each Brand feature and its weight from the Brand Feature Set 1201 are retrieved in turn by the Feature Retrieval process 1205 . For every retrieved feature the values of the feature for the Source Brand 1202 and the Target Brand 1203 are retrieved by the Feature Retrieval process 1207 . The Comparison process 1209 compares the feature values, and the Similarity Score Update process 1210 updates the similarity score by the similarity between the Source Brand 1202 and the Target Brand 1203 with respect to the currently considered feature, computed by the Comparison process 1209 multiplied by the weight W for the current Brand Feature. Upon consideration of all features from the Brand Feature Set 1201 by the cycle 1206 , 1205 , 1207 , 1209 , 1210 , the final value of the similarity score, computed on the last iteration of the Similarity Score Update process 1210 is output by the Output component 1208 . [0103] FIG. 13 illustrates an exemplary embodiment of a computer platform upon which the inventive system may be implemented. Specifically, FIG. 13 represents a block diagram that illustrates an embodiment of a computer/server system 1300 upon which an embodiment of the inventive methodology may be implemented. The system 1300 includes a computer/server platform 1301 , peripheral devices 1302 and network resources 1303 . [0104] In one or more embodiments, the computer platform 1301 may include a data bus 1304 or other communication mechanism for communicating information across and among various parts of the computer platform 1301 , and a processor 1305 coupled with bus 1304 for processing information and performing other computational and control tasks. Computer platform 1301 also includes a volatile storage 1306 , such as a random access memory (RAM) or other dynamic storage device, coupled to bus 1304 for storing various information as well as instructions to be executed by processor 1305 . The volatile storage 1306 also may be used for storing temporary variables or other intermediate information during execution of instructions by processor 1305 . Computer platform 1301 may further include a read only memory (ROM or EPROM) 1307 or other static storage device coupled to bus 1304 for storing static information and instructions for processor 1305 , such as basic input-output system (BIOS), as well as various system configuration parameters. A persistent storage device 1308 , such as a magnetic disk, optical disk, or solid-state flash memory device is provided and coupled to bus 1304 for storing information and instructions. [0105] Computer platform 1301 may be coupled via bus 1304 to a display 1309 , such as a cathode ray tube (CRT), plasma display, or a liquid crystal display (LCD), for displaying information to a system administrator or user of the computer platform 1301 . An input device 1310 , including alphanumeric and other keys, is coupled to bus 1304 for communicating information and command selections to processor 1305 . Another type of user input device is cursor control device 1311 , such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor 1305 and for controlling cursor movement on display 1309 . This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allows the device to specify positions in a plane. [0106] An external storage device 1312 may be coupled to the computer platform 1301 via bus 1304 to provide an extra or removable storage capacity for the computer platform 1301 . In an embodiment of the computer system 1300 , the external removable storage device 1312 may be used to facilitate exchange of data with other computer systems. [0107] The invention is related to the use of computer system 1300 for implementing the techniques described herein. In an embodiment, the inventive system may reside on a machine such as computer platform 1301 . According to one embodiment of the invention, the techniques described herein are performed by computer system 1300 in response to processor 1305 executing one or more sequences of one or more instructions contained in the volatile memory 1306 . Such instructions may be read into volatile memory 1306 from another computer-readable medium, such as persistent storage device 1308 . Execution of the sequences of instructions contained in the volatile memory 1306 causes processor 1305 to perform the process steps described herein. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement the invention. Thus, embodiments of the invention are not limited to any specific combination of hardware circuitry and software. [0108] The term “computer-readable medium” as used herein refers to any medium that participates in providing instructions to processor 1305 for execution. The computer-readable medium is just one example of a machine-readable medium, which may carry instructions for implementing any of the methods and/or techniques described herein. Such a medium may take many forms, including but not limited to, non-volatile media and volatile media. Non-volatile media includes, for example, optical or magnetic disks, such as storage device 1308 . Volatile media includes dynamic memory, such as volatile storage 1306 . [0109] Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CDROM, any other optical medium, punchcards, papertape, any other physical medium with patterns of holes, a RAM, a PROM, an EPROM, a FLASH-EPROM, a flash drive, a memory card, any other memory chip or cartridge, or any other medium from which a computer can read. [0110] Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to processor 1305 for execution. For example, the instructions may initially be carried on a magnetic disk from a remote computer. Alternatively, a remote computer can load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to computer system can receive the data on the telephone line and use an infrared transmitter to convert the data to an infra-red signal. An infra-red detector can receive the data carried in the infra-red signal and appropriate circuitry can place the data on the data bus 1304 . The bus 1304 carries the data to the volatile storage 1306 , from which processor 1305 retrieves and executes the instructions. The instructions received by the volatile memory 1306 may optionally be stored on persistent storage device 1308 either before or after execution by processor 1305 . The instructions may also be downloaded into the computer platform 1301 via Internet using a variety of network data communication protocols well known in the art. [0111] The computer platform 1301 also includes a communication interface, such as network interface card 1313 coupled to the data bus 1304 . Communication interface 1313 provides a two-way data communication coupling to a network link 1315 that is coupled to a local network 1315 . For example, communication interface 1313 may be an integrated services digital network (ISDN) card or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface 1313 may be a local area network interface card (LAN NIC) to provide a data communication connection to a compatible LAN. Wireless links, such as well-known 802.11a, 802.11b, 802.11g and Bluetooth may also be used for network implementation. In any such implementation, communication interface 1313 sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information. [0112] Network link 1313 typically provides data communication through one or more networks to other network resources. For example, network link 1315 may provide a connection through local network 1315 to a host computer 1316 , or a network storage/server 1317 . Additionally or alternatively, the network link 1313 may connect through gateway/firewall 1317 to the wide-area or global network 1318 , such as an Internet. Thus, the computer platform 1301 can access network resources located anywhere on the Internet 1318 , such as a remote network storage/server 1319 . On the other hand, the computer platform 1301 may also be accessed by clients located anywhere on the local area network 1315 and/or the Internet 1318 . The network clients 1320 and 1321 may themselves be implemented based on the computer platform similar to the platform 1301 . [0113] Local network 1315 and the Internet 1318 both use electrical, electromagnetic or optical signals that carry digital data streams. The signals through the various networks and the signals on network link 1315 and through communication interface 1313 , which carry the digital data to and from computer platform 1301 , are exemplary forms of carrier waves transporting the information. [0114] Computer platform 1301 can send messages and receive data, including program code, through the variety of network(s) including Internet 1318 and LAN 1315 , network link 1315 and communication interface 1313 . In the Internet example, when the system 1301 acts as a network server, it might transmit a requested code or data for an application program running on client(s) 1320 and/or 1321 through Internet 1318 , gateway/firewall 1317 , local area network 1315 and communication interface 1313 . Similarly, it may receive code from other network resources. [0115] The received code may be executed by processor 1305 as it is received, and/or stored in persistent or volatile storage devices 1308 and 1306 , respectively, or other non-volatile storage for later execution. [0116] It should be understood that processes and techniques described herein are not inherently related to any particular apparatus and may be implemented by any suitable combination of software components. Further, various types of general purpose software components may be used in accordance with the teachings described herein. It may also prove advantageous to extend the taxonomy as well as number of media Channels and Channel Actions to perform the method steps described herein. The present invention has been described in relation to particular examples, which are intended in all respects to be illustrative rather than restrict. Those skilled in the art will appreciate that many different combinations of software components, and software services will be suitable for practicing the present invention. For example, the described software may be implemented in a wide variety of programming or scripting languages, such as .NET, PHP, Java, etc. [0117] Moreover, other implementations of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. Various aspects and/or components of the described embodiments may be used singly or in any combination in the computerized system and computer-implemented method for generating marketing recommendations. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

A computerized recommender system and an associated computer-implemented method, which accumulate and analyze the information about various marketing actions for promoting brands as well as information about the subsequent brand performance within media channels. The channels include, but are not limited to web, blogs, social networks, search engines, contextual ad networks, email campaigns, and other promotional activities. Additional media channels can be added into the recommender system. The described recommender system enables the marketers to obtain custom advice for a given brand as to what should be the next most effective marketing actions to promote the brand.

FIELD OF THE INVENTION [0001] The present invention related to the cosmetic field, in particular it relates to a skin care composition and product with beneficial cosmetic effects and/or effects of relieving common undesirable skin conditions or symptoms. BACKGROUND OF THE INVENTION [0002] Skin aging is part of the aging process of human body, which not only relates to the age itself, but also closely relates to sunlight exposure. The light induced skin aging (“light-aging”) is mainly caused by sunlight irradiation, and as depletion of the ozone layer is aggravating, the light-aging of the skin becomes more and more serious, which affects not only the appearance, but may also cause underlying etiological problems relating to skin cancer. [0003] Extracts of traditional herbal medical materials used in China (“TCM”) generally comprises many active ingredients, such as saponins, flavonoids, and alkaloids, many of which ingredients have various skin-care functions. Beauty and skin-care products based on herbal ingredients have thousands of years of history in China. Particularly, nowadays, people prefer natural substances rather than chemically synthesized substances. Therefore, herbal medicine cosmetic products are getting more popular. SUMMARY OF THE INVENTION [0004] An object of the present invention is to provide a skin care composition with beneficial cosmetic effects and/or effects of relieving common skin symptoms. The object is achieved by the following technical solution: selecting active ingredients for their effects of regulating immunity and for their effects in delaying skin aging process induced by sunlight and formulating a skin care composition comprising a powder part, an aqueous part and an emulsion part. The ingredients for each part and the rationale for their selection are summarized in the following. [0005] The powder part comprises the following ingredients in portion by weight: [0000] Oligopeptide-1 0~1.0 portion Ginseng saponin 0~5.0 portions [0006] and at least one of the two ingredients must be present. [0007] The aqueous part comprises the following ingredients in portion by weight: [0000] Glycyrrhiza glabra Root Extract 0~3.0 portions Artemisia capillaris Flower Extract 0~3.0 portions Radix Mori Albae Extract 0~2.0 portions Zizyphus jujuba Fruit Extract 0~2.0 portions Scutellaria baicalensis Root Extract 0~2.0 portions hydrolyzed rice protein 0~5.0 portions nicotinamide 0~3.0 portions [0008] and at least one of the ingredients must be present. [0009] The emulsion part comprises the following ingredients in portion by weight: [0000] Bifida ferment lysate 0.5~10.0 portions   creatine 0~2.0 portions carnosine 0~2.0 portions Glucosyl Hesperidin 0~5.0 portions Hexapeptide-3 0~5.0 portions Centella asiatica Extract 0~3.0 portions Coenzyme Q10 capsule 0~2.0 portions Opuntia Ficus-indica Stem Extract 0~5.0 portions Rhodiola rosea Extract 0~2.0 portions Saussurea Involucrata Extract 0~5.0 portions Panax notoginseng Root Extract 0~5.0 portions Angelica sinensis Extract capsule 0~5.0 portions [0010] and, in addition to Bifida ferment lysate, one of the other ingredients must be present. [0011] In the powder part, Oligopeptide-1 is an epidermal growth factor, which is a protein secreted by microorganism in a high density and highly purified form, and has a biological effect of promoting the growth and metabolism of skin epidermal cells. Ginseng saponin might be the total saponins extracted and processed from the root of Panax plant Panax ginseng C. A. Mey, or may be any monomer of Ginseng saponin or the mixture of various monomers of Ginseng saponin, such as the mixture of one or two of Ginseng saponin Rb1, Rb2, Rb3, Rc, Rd, Rg3 and Rh2. [0012] In the aqueous formulation, hydrolyzed rice protein is the zymolyte obtained through the co-hydrolysis of rice protein by alkaline protease and complex protease, which comprises thymic penta peptide. It can prevent the UV-induced atrophy of langerhans cells, prevent the UV-induced change of skin structure and integrity, protect the skin structure and integrity thereof, and promote the synthesis of β1-integrin, keratin and filaggrin, so that the immune activity of skin is enhanced. It is proved by the culture experiment of human keratinocytes that the hydrolyzed rice protein can improve cellular vitality by 34%. [0013] Glycyrrhiza glabra Root Extract comprises Glabridin, an isoflavones component, whose chemical structure comprises the nucleus of isoflavone, with ring A and ring B as aromatic rings, and ring B comprising 2 phenolic hydroxyl groups, and an ethylene bond on C9, therefore has a rather strong anti-oxidation activity. Rhodiola rosea has an effect on immune regulation, and it prevents the UV-caused fibroblast apoptosis, and delays the light-aging of skin. [0014] The emulsion part of the present invention may be lotion, gel and cream formulations, where, Bifida ferment lysate is the lysate solution of Bifidobacterium obtained by means of bio-technique, which comprises metabolic product, cytoplasmic component, cell wall component and polysaccharide complex. It is found in studies that UV irradiation will reduce the secretion of IL-12, affect the proliferation of NK cells and T cells, increase the expression of IL-10 and cause immunosuppression, and thereby render DNA damage. It is proved by experiments that Bifida ferment lysate can fight against the immune suppression caused by the UV-induced increase of IL-10 expression, stimulate the natural repair mechanism (matrix) of skin DNA after the UV irradiation, and postpone the UV-caused aging of skin. [0015] Creatine can accumulate the stored energy of cells, thereby increasing the available ATP, and promote DNA repair and the DNA synthesis of cells after UV irradiation injury, which reduces the sunburn of cells induced by UV obviously and postpones the aging process of skin. [0016] Carnosine, also termed as dipeptide or β-alanyl-L-histidine, has the effects of removing active free radicals, against oxidation, against glycosylation reaction, against protein cross-linking, chelating heavy metal ions, and postponing the shortening process of telomere, thus postpones the aging of skin. [0017] Hesperidin is a kind of natural biological flavonoids extracted from citrus peel and termed as “Vitamin P”, it has the effects of strengthening capillary resistance, reducing permeability and anti-inflammation. Glucosyl Hesperidin is a derivative of water-soluble Hesperidin, whose water solubility is increased by enzymatic combination techniques. It is proved by experiments that Glucosyl Hesperidin has the effects of enhancing blood circulation, improving skin tone and brightness. [0018] Hexapeptide-3 is homologous substance having a 6-amino acid sequence in the Type-III unit of fibronectin protein molecule. It is proved by experiments that Hexapeptide-3 can improve cellular adhesion and the expression of β1-integrin, facilitate a more even cellular extension on collagen, thus contribute to the prevention of light aging of skin. [0019] Centella asiatica Extract comprises the active components, being total triterpene of Centella asiatica and madecassoside, which have the effects of promoting the proliferation of human fibroblasts in the skin, promoting the synthesis of collagen and inhibiting inflammation. Centella asiatica Extract can promote the regeneration of aged skin and promote the healing of wound. [0020] Coenzyme Q10 is an anti-oxidant, which is the activator of cellular respiration and metabolism, it can bring energy and vitality to the body and skin, and can scavenge the active oxygen from the body. When the skin is affected externally or internally, a large number of free radicals are produced during the inflammatory procedure, whereas Coenzyme Q10 can remove free radicals and postpone skin aging. It is proved by experiments that, by improving the activity of Cathepsin D, stratum corneum chymotrypsin (SCCE) and stratum corneum trypsin-like enzymes (SCTE), Opuntia Ficus - indica Stem Extract can promote the shedding of keratinocytes, accelerate cell renewal, improve the transparency and gloss of skin, and reduce fine lines and wrinkles. [0021] Saussurea Involucrata Extract comprises the active components of polysaccharide and flavone, it has the effects of promoting and regulating immune function, as well as fighting against free radicals. Together with other polysaccharide components and fibrous protein in the skin, it can form extracellular gel matrix comprising a large amount of moisture to moisturize the skin, delay the aging problems of skin, such as drying and loss of elasticity, etc. The active component of Panax notoginseng Root is Notoginseng total saponin, it has an obvious effect on improving the skin SOD activity, reducing MDA content and improving the hydroxyproline in the skin. [0022] Angelica sinensis is the dried Root of Umbrelliferae plant Angelica sinensis , it is able to eliminate free radicals, complex ferrous ion and inhibit tyrosinase, and has the effects of preventing skin aging and promoting skin whitening. Angelica sinensis Root mainly comprises volatile oil and non-volatile oil components, with heavy odor. Through encapsulation, the odor is reduced; meanwhile, the active ingredient are made easily permeable. [0023] The Coenzyme Q10 capsule refers to the Coenzyme Q10 encapsulated by means of conventional liposome encapsulation techniques. [0024] Preferably, the weight portions of the components of the powder part are: [0000] Oligopeptide-1 0.01~0.5 portion Ginseng saponin    0.1~2.0 portions. [0025] More preferably, the weight portions of the components of the powder part are: [0000] Oligopeptide-1 0.01~0.05 portion Ginseng saponin  0.10~0.50 portion. [0026] Preferably, the weight portions of the components of the aqueous part are: [0000] Glycyrrhiza glabra Root Extract 0.10~1.50 portions Artemisia capillaris Flower Extract 0.10~1.50 portions Radix Mori Albae Extract 0.10~1.00 portion Zizyphus jujuba Fruit Extract 0.10~1.00 portion Scutellaria baicalensis Root Extract 0.10~1.00 portion hydrolyzed rice protein 0.10~2.00 portions nicotinamide 0.10~1.50 portions. [0027] More preferably, the weight portions of the components of the aqueous part are: [0000] Glycyrrhiza glabra Root Extract 0.5~1.0 portion Artemisia capillaris Flower Extract 0.5~1.0 portion Radix Mori Albae Extract 0.5~1.0 portion Zizyphus jujuba Fruit Extract 0.5~1.0 portion Scutellaria baicalensis Root Extract 0.5~1.0 portion hydrolyzed rice protein 0.5~1.0 portion nicotinamide 0.50~1.0 portion.  [0028] Preferably, the weight portions of the components of said emulsion part are: [0000] Rhodiola rosea Extract 0.1~2.0 portions Bifida ferment lysate 0.5~5.0 portions creatine 0.5~1.5 portions carnosine 0.1~1.0 portion Glucosyl Hesperidin 0.1~2.0 portion Hexapeptide-3 0.5~1.5 portions Centella asiatica Extract 0.1~1.0 portion Coenzyme Q10 capsule 0.1~1.0 portion Opuntia Ficus-indica Stem Extract 0.1~3.0 portions. [0029] Besides the aforesaid major ingredients, the powder part, aqueous part and emulsion part according to the present invention may also include the common matrix for the external dosage form of cosmetics. They include excipients such as mannitol, disodium hydrogen phosphate and sodium dihydrogen phosphate. The common matrix for aqueous formulation comprises excipients such as sodium hyaluronate, oxhide glue, butanediol, disodium EDTA, dipotassium glycyrrhetate, panthenol and preservatives. The common matrix for emulsion formulation comprises excipients such as bisabolol, cetylhydroxyproline palmitamide, brassica campestris sterol, jojoba seed oil, phytosterol isostearate, Vitamin E acetate, silicone oil, Cetyl stearyl alcohol, Sucrose polystearate, Beheneth-25, Dipalmitoyl hydroxyproline, Acrylates/C10-30 alkyl acrylate crosspolymer, butanediol, glycerin, Sodium stearoyl glutamate, disodium EDTA, xanthan gum, deionized water, acrylamide/ammonia acrylate copolymer (and) Poly(isobutylene) (and) Polysorbate-20, 1-methylhydantoin-2-imide, preservatives. [0030] The present invention has the following beneficiary effects: [0031] (1). The combined administration of the three parts of the product has an effect of reducing wrinkles, reducing skin roughness, fading uneven skin tone, improving skin elasticity, firming skin, making the skin more delicate and looking younger. [0032] (2) The product can produce its effects quickly, and only requires intermittent administration, e.g., an administration of 28 days (one period) in 3 months, or it is administered when the skin condition is unsatisfying. [0033] (3) The separation of the powder part, aqueous part and emulsion part of the present invention ensures the active components intact during the storage process, thereby ensuring their effects and function when used. BRIEF DESCRIPTION OF THE DRAWINGS [0034] FIG. 1 shows the overall effect of the skin care product of two particular embodiments on volunteers participated in a trial in comparison with a comparative products available in the prior art. [0035] FIG. 2 shows the effects on specific skin conditions in the same trial as FIG. 2 of two particular embodiments and a comparative products available in the prior art. [0036] The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be made to the drawings and the following description in which there are illustrated and described preferred embodiments of the invention. DETAILED DESCRIPTION OF THE INVENTION [0037] The present invention will be further described as follows in combination with specific embodiments, but the embodiments shall not restrict the present invention in any forms. The material and ingredients used in the embodiments are all commercially available. Unless specifically addressed, the portion number of each ingredient in the following description is weight portion. Embodiment 1 1. Preparation of the Powder Part: [0038] The ingredients are: [0000] Oligopeptide-1 0.1 portion; Ginseng saponin 1.0 portion; mannitol 10.0 portions;   disodium hydrogen phosphate 0.5 portion; sodium dihydrogen phosphate 0.2 portion. [0039] The preparation process is as follows: [0040] (1) Dissolve all the components in an appropriate amount of deionized water, and filter the resulting solution through a 0.2 μm membrane. [0041] (2) Fill it into small glass vials, and place the vials into a vacuum freeze drier. [0042] (3) Vacuum dry for 45 hours so that it is in the form of powder. 2. Preparation of Aqueous Part: [0043] The ingredients are: [0000] Glycyrrhiza glabra Root Extract 2.0 portions; Artemisia capillaris Flower Extract 2.0 portions; Radix Mori Albae Extract 1.0 portion; Zizyphus jujuba Fruit Extract 1.0 portion; Scutellaria baicalensis Root Extract 1.0 portion; hydrolyzed rice protein 3.0 portions; nicotinamide 2.0 portions; sodium hyaluronate 0.5 portion; butanediol 10.0 portions; disodium EDTA 0.5 portion; dipotassium glycyrrhetate 1.0 portion; panthenol 5.0 portions; preservatives 0.1 portion; deionized water in an appropriate amount. [0044] The molecular weight of the sodium hyaluronate is 300,000. [0045] The preparation process is as follows: [0046] (1) Add sodium hyaluronate to the deionized water, and stir to dissolve. [0047] (2) Add all other components and stir to dissolve. [0048] (3) Adjust the resulting solution to pH 5.5˜7.0, and passing quality examination fill it into small vials. 3. Preparation of a Lotion Part [0049] The ingredients are: Phase A: [0050] [0000] jojoba seed oil 8 portions; phytosterol isostearate 5 portions; Vitamin E acetate 3 portions; Rhodiola rosea Extract 0.1 portion;    Palmitoyl hydrolyzed wheat protein 3 portions; Cetyl stearyl alcohol 2 portions; Sucrose polystearate 2 portions; hydrogenated Poly(isobutylene) 5 portions; Dipalmitoyl hydroxyproline 2 portions; Phase B: [0051] [0000] Acrylates/C10-30 alkyl acrylate crosspolymer 0.5 portion; butanediol 10 portions; glycerin 5 portions; Sodium stearoyl glutamate 1 portion; disodium EDTA 0.1 portion; xanthan gum 0.5 portion; deionized water margin; Phase C: [0000] acrylamide/ammonia acrylate copolymer (and) Poly(isobutylene) 2.0 portions; (and) Polysorbate-20 Phase D: [0053] [0000] aminomethyl propanol 0.2 portion 1-methylhydantoin-2-imide 1.0 portion; creatine 0.5 portion; carnosine 0.5 portion; Glucosyl Hesperidin 1.0 portion; dipotassium glycyrrhetate 2.0 portions; Bifida ferment lysate 5.0 portions; Hexapeptide-3 0.5 portion Centella asiatica Extract 1.0 portion; Coenzyme Q10 capsule 1.0 portion; Opuntia Ficus-indica Stem Extract 2.0 portions; Saussurea Involucrata Extract 0.5 portion; Panax notoginseng Root Extract 0.5 portion; Angelica sinensis Extract capsule 0.5 portion; preservatives 0.1 portion. [0054] The preparation process is as follows: [0055] (1) All components in Phase A are mixed evenly, heated to 80° C., stirred to dissolve to obtain Phase A solution; [0056] (2) Acrylates/C10-30 alkyl acrylate crosspolymer is added to deionized water, stirred to dissolve, then other raw materials in Phase B are added, heated to 80° C., stirred to dissolve to obtain Phase B solution; [0057] (3) Phase A solution is added to Phase B solution, and then all components in Phase C are added, stirred to homogenize to be emulsified; [0058] (4) The mixture is stirred and cooled to 45° C., aminomethyl propanol is added, stirred to dissolve, and then other raw materials in Phase D are added, stirred and cooled to 30˜35° C.; [0059] (5) A lotion is obtained, whose pH value is adjusted to 5.5˜6.5, upon passing quality examination, filled to the vessels. Embodiment 2 1. Preparation of Powder Part [0060] The ingredients are: [0000] Oligopeptide-1 0.5 portion; Ginseng saponin 2.0 portions; mannitol  15 portions; disodium hydrogen phosphate 0.5 portion; sodium dihydrogen phosphate 0.2 g portion. [0061] The preparation process is as follows: [0062] (1) All components are dissolved in an appropriate amount of deionized water, then the obtained solution is filtered through a 0.2 μm membrane. [0063] (2) The solution is loaded on to a plate which is put into a vacuum freeze drier. [0064] (3) The solution is being vacuum dried for 45 hours into a form of powder, which is then distributed into small vials. 2. Preparation of Aqueous Part [0065] The ingredients are: [0000] Glycyrrhiza glabra Root Extract 0.5 portion Artemisia capillaris Flower Extract 0.5 portion Radix Mori Albae Extract 0.5 portion Zizyphus jujuba Fruit Extract 0.5 portion Scutellaria baicalensis Root Extract 0.5 portion hydrolyzed rice protein 1.0 portion sodium hyaluronate 0.5 portion butanediol 8.0 portions disodium EDTA 0.1 portion dipotassium glycyrrhetate 0.5 portion panthenol 0.5 portion nicotinamide 0.3 portion xanthan gum 1.2 portions preservatives 0.1 portion deionized water in an appropriate amount. [0066] The molecular weight of the sodium hyaluronate is 300,000. [0067] The preparation process is as follows: [0068] (1) Xanthan gum is added to the deionized water, stirred to dissolve. [0069] (2) All the other components are added to the solution of (1), stirred to dissolve. [0070] (3) An aqueous formulation is obtained, which is adjusted to PH to 5.5˜6.5, and after passing the quality examination, filled into vessels. 3. Preparation of a Cream [0071] The ingredients are: Phase A: [0072] [0000] jojoba seed oil 5 portions phytosterol isostearate 2 portions Vitamin E acetate 5 portions Rhodiola rosea Extract 0.5 portion Cetyl stearyl alcohol 3 portions Sucrose polystearate 5 portions Dipalmitoyl hydroxyproline 2 portions Phase B: [0073] [0000] Acrylates/C10-30 alkyl acrylate crosspolymer 1.5 portions butanediol 15 portions glycerin 15 portions Sodium stearoyl glutamate 0.5 portion disodium EDTA 0.1 portion xanthan gum 0.5 portion deionized water margin Phase C: [0000] acrylamide/ammonia acrylate copolymer (and) Poly(isobutylene) 2.0 portions; (and) Polysorbate-20 Phase D: [0075] [0000] aminomethyl propanol 0.15 portion 1-methylhydantoin-2-imide 1.0 portion creatine 0.5 portion carnosine 0.5 portion Glucosyl Hesperidin 1.0 portion dipotassium glycyrrhetate 2.0 portions Bifida ferment lysate 5.0 portions Hexapeptide-3 1.0 portion Centella asiatica Extract 1.0 portion Coenzyme Q10 capsule 1.0 portion Opuntia Ficus-indica Stem Extract 2.0 portions Saussurea Involucrata Extract 0.5 portion Panax notoginseng Root Extract 0.5 portion Angelica sinensis Extract capsule 0.5 portion preservatives 0.1 portion [0076] The preparation is as follows: [0077] (1) The components in Phase A are heated to 80˜90° C., stirred to dissolve. [0078] (2) Acrylates/C10-30 alkyl acrylate crosspolymer is added to deionized water, stirred to dissolve, then other raw materials in Phase B are added, heated to 80˜90° C., stirred to dissolve. [0079] (3) Phase A is added to Phase B, stirred to homogenize to be emulsified, and meanwhile, the raw materials in Phase C are added; [0080] (4) The above mixture is stirred and cooled to 45° C., and aminomethyl propanol is added, stirred to dissolve, and then other raw materials in Phase D are added, stirred and cooled to 30˜35° C.; [0081] (5) A cream is obtained, whose pH value is adjusted to 5.5˜7.0; [0082] (6) Passing quality examination, the cream is then filled into vessels. Example 3 1. Preparation of Powder Part [0083] The ingredients are: [0000] Oligopeptide-1 0.5 portion Ginseng saponin 2.0 portions mannitol margin; [0084] The preparation process is as follows: [0085] (1) All components are mixed evenly. [0086] (2) The mixture are divided into small portions and filled into sachets. 2. Preparation of Aqueous Part [0087] The ingredients are: [0000] Glycyrrhiza glabra Root Extract 2.0 portions Artemisia capillaris Flower Extract 2.0 portions Radix Mori Albae Extract 1.0 portion Zizyphus jujuba Fruit Extract 1.0 portion Scutellaria baicalensis Root Extract 1.0 portion hydrolyzed rice protein 3.0 portions glycerin 10.0 portions disodium EDTA 0.1 portion dipotassium glycyrrhetate 2.0 portions panthenol 0.5 portion nicotinamide 1.0 portion Acrylates/C10-30 alkyl acrylate crosspolymer 1.0 portion aminomethyl propanol 0.15 portion preservatives 0.10 portion deionized water in an appropriate amount. [0088] The molecular weight of the sodium hyaluronate is 300,000. [0089] The preparation process is as follows: [0090] (1) Acrylates/C10-30 alkyl acrylate crosspolymer is added to the deionized water, stirred to disperse, aminomethyl propanol is added, stirred to dissolve completely. [0091] (2) All the other components are added to (1), stirred to dissolve. [0092] (3) Adjusted pH to 5.5˜7.0. [0093] (4) Upon passing quality control, fill it into vessels. 3. Preparation of a Gel [0094] The ingredient are: Phase A: [0095] [0000] Cetyl stearyl alcohol 2 portions Sucrose polystearate 2 portions Dipalmitoyl hydroxyproline 2 portions Rhodiola rosea Extract 0.1 portion Phase B: [0000] Acrylates/C10-30 alkyl acrylate crosspolymer 3 portions [0000] butanediol  10 portions glycerin   5 portions disodium EDTA 0.1 portion xanthan gum 0.5 portion deionized water margin Phase C: [0000] acrylamide/ammonia acrylate copolymer (and) Poly(isobutylene) 2.0 portions; (and) Polysorbate-20 Phase D: [0098] [0000] aminomethyl propanol 0.3 portion creatine 0.5 portion carnosine 0.5 portion Glucosyl Hesperidin 1.0 portion dipotassium glycyrrhetate 2.0 portions Bifida ferment lysate 5.0 portions Hexapeptide-3 0.5 portion Centella asiatica Extract 1.0 portion Coenzyme Q10 capsule 1.0 portion Opuntia Ficus-indica Stem Extract 2.0 portions Saussurea Involucrata Extract 0.5 portion Panax notoginseng Root Extract 0.5 portion Angelica sinensis Extract capsule 0.5 portion preservatives 0.1 portion. [0099] The preparation process is as follows: [0100] (1) The raw materials in Phase A are heated to 80˜90° C., stirred to dissolve; [0101] (2) Acrylates/C10-30 alkyl acrylate crosspolymer is added to deionized water, stirred to dissolve, then other raw materials in Phase B are added, heated to 80˜90° C., stirred to dissolve. [0102] (3) Phase A is added to Phase B, stirred to homogenize to be emulsified, and meanwhile, the raw materials in Phase C are added; [0103] (4) The above mixture is stirred and cooled to 45° C., aminomethyl propanol is added, stirred to dissolve, and then other raw materials in Phase D are added, stirred and cooled to 30˜35° C.; [0104] (5) A gel is obtained, whose pH value is adjusted to 5.5˜7.0; [0105] (6) Upon passing examination, the gel is then filled into vessels. Example 4 1. Preparation of Powder Part [0106] The ingredients are: [0000] Oligopeptide-1 0.001 portion; Ginseng saponin 0.1 portion; mannitol 5.0 portions; disodium hydrogen phosphate 0.5 portion; sodium dihydrogen phosphate 0.2 portion. [0107] The preparation process is as follows: [0108] (1) All components are dissolved in an appropriate amount of deionized water, then the obtained solution is sterilized in an autoclave at 121° C., 0.1 Mpa for 30 mins. [0109] (2) It is distributed into small glass vials, and then place them into a vacuum freeze drier. [0110] (3) It is then vacuum dried for 45 hours into the form of powder, and then vials are capped. 2. Preparation of Aqueous Part [0111] The ingredients are: [0000] Glycyrrhiza glabra Root Extract 0.5 portion; Artemisia capillaris Flower Extract 0.5 portion; Radix Mori Albae Extract 0.3 portion; Zizyphus jujuba Fruit Extract 0.3 portion; Scutellaria baicalensis Root Extract 0.3 portion; hydrolyzed rice protein 1.0 portion; nicotinamide 0.5 portion; sodium hyaluronate 0.1 portion; butanediol 8.0 portions; disodium EDTA 0.1 portion; dipotassium glycyrrhetate 0.1 portion; panthenol 0.5 portion; preservatives 0.01 portion; deionized water in an appropriate amount. [0112] The molecular weight of the sodium hyaluronate is 300,000. [0113] The preparation process is as follows: [0114] (1) Sodium hyaluronate is added to the deionized water, stirred to dissolve. [0115] (2) Other components are added, stirred to dissolve. [0116] (3) An aqueous part is obtained, whose pH value is adjusted to 5.5˜7.0, and upon passing quality control, filled into vials. 3. Preparation of a Lotion [0117] The ingredients are: Phase A: [0118] [0000] phytosterol isostearate 0.5 portion; Vitamin E acetate 1 portion; Cetyl stearyl alcohol 1 portion; Sucrose polystearate 2 portions; Dipalmitoyl hydroxyproline 1 portion; Rhodiola rosea Extract 0.1 portion Phase B: [0119] [0000] Acrylates/C10-30 alkyl acrylate crosspolymer 0.1 portion; butanediol 5 portions; glycerin 2 portions; Sodium stearoyl glutamate 0.5 portion; disodium EDTA 0.1 portion; xanthan gum 0.1 portion; deionized water margin; Phase C: [0000] acrylamide/ammonia acrylate copolymer (and) Poly(isobutylene) 1.0 portion; (and) Polysorbate-20 Phase D: [0121] [0000] aminomethyl propanol 0.2 portion  1-methylhydantoin-2-imide 1.0 portion; creatine 0.2 portion; carnosine 0.2 portion; Glucosyl Hesperidin 0.5 portion; dipotassium glycyrrhetate 0.1 portion; Bifida ferment lysate 1.0 portion; Centella asiatica Extract 0.5 portion; Coenzyme Q10 capsule 0.5 portion; Opuntia Ficus - indica Stem Extract 1.0 portion; Hexapeptide-3 1.0 portion; Saussurea Involucrata Extract 0.1 portion; Panax notoginseng Root Extract 0.1 portion; Angelica sinensis Extract capsule 0.1 portion; preservatives 0.05 portion.  [0122] The preparation process is as follows: [0123] (1) All components in Phase A are mixed evenly, heated to 80° C., stirred to dissolve to obtain Phase A solution. [0124] (2) Acrylates/C10-30 alkyl acrylate crosspolymer is added to deionized water, stirred to dissolve, then other raw materials in Phase B are added, heated to 80° C., stirred to dissolve to obtain Phase B solution. [0125] (3) Phase A solution is added to Phase B solution, and then all components in Phase C are added, stirred to homogenize to be emulsified. [0126] (4) The above mixture is stirred and cooled to 45° C., aminomethyl propanol is added, stirred to dissolve, and then other raw materials in Phase D are added, stirred and cooled to 30˜35° C.; [0127] (5) A lotion is obtained, whose pH value is adjusted to 5.5˜6.5, and upon passing quality control, filled into the vessels. Example 5 1. Preparation of Powder Part [0128] The ingredients are: [0000] Oligopeptide-1 1.0 portion; Ginseng saponin   5.0 portions; mannitol 20.0 portions.   [0129] The preparation process is as follows: [0130] (1) All components are dissolved in an appropriate amount of deionized water, then the obtained solution is sterilized in an autoclave at 121° C., 0.1 Mpa for 30 mins. [0131] (2) Distribute it into glass vials, and then put into the vacuum freeze drier. [0132] (3) Vacuum freeze dried for 45 hours, to form a powder, then cap the vials. 2. Preparation of Aqueous Part [0133] The ingredients are: [0000] Glycyrrhiza glabra Root Extract 3.0 portions; Artemisia capillaris Flower Extract 3.0 portions; Radix Mori Albae Extract 2.0 portions; Zizyphus jujuba Fruit Extract 2.0 portions; Scutellaria baicalensis Root Extract 2.0 portions; hydrolyzed rice protein 5.0 portions; nicotinamide 3.0 portions; sodium hyaluronate 2.0 portions; butanediol 20.0 portions;  disodium EDTA 0.1 portion;   dipotassium glycyrrhetate 2.0 portions; panthenol 5.0 portions; preservatives 0.01 portion;    deionized water in an appropriate amount. [0134] The molecular weight of the sodium hyaluronate is 300,000. [0135] The preparation process is as follows: [0136] (1) Sodium hyaluronate is added to the deionized water, stirred to dissolve. [0137] (2) Other components are added, stirred to dissolve; [0138] (3) An aqueous part is obtained, whose pH value is adjusted to 5.5˜7.0, upon passing quality examination, filled into vessels. 3. Preparation of a Lotion [0139] The ingredients are: Phase A: [0140] [0000] phytosterol isostearate 0.5 portion;   Vitamin E acetate   3 portions; Rhodiola rosea Extract 2.0 portions    Cetyl stearyl alcohol 1 portion; Sucrose polystearate   2 portions; Dipalmitoyl hydroxyproline 1 portion; Phase B: [0000] Acrylates/C10-30 alkyl acrylate crosspolymer 0.1 portion; [0000] butanediol     5 portions; glycerin     2 portions; Sodium stearoyl glutamate 0.5 portion; disodium EDTA 0.1 portion; xanthan gum 0.1 portion; deionized water margin; Phase C: [0000] acrylamide/ammonia acrylate copolymer (and) Poly(isobutylene) 1.0 portion; (and) Polysorbate-20 Phase D: [0143] [0000] aminomethyl propanol 0.2 portion; 1-methylhydantoin-2-imide 1.0 portion; creatine   2.0 portions; carnosine   2.0 portions; Glucosyl Hesperidin   5.0 portions; dipotassium glycyrrhetate 0.1 portion; Bifida ferment lysate 10.0 portions;   Hexapeptide-3   5.0 portions Centella asiatica Extract   3.0 portions; Coenzyme Q10 capsule 0.5 portion; Opuntia Ficus - indica Stem Extract 1.0 portion; Saussurea Involucrata Extract 0.1 portion; Panax notoginseng Root Extract 0.1 portion; Angelica sinensis Extract capsule 0.1 portion; preservatives. 0.05 portion.  [0144] The preparation process as follows: [0145] (1) All components in Phase A are mixed evenly, heated to 80° C., stirred to dissolve to obtain Phase A solution. [0146] (2) Acrylates/C10-30 alkyl acrylate crosspolymer is added to deionized water, stirred to dissolve, then other raw materials in Phase B are added, heated to 80° C., stirred to dissolve to obtain Phase B solution. [0147] (3) Phase A solution is added to Phase B solution, and all components in Phase C are added, stirred to homogenize to be emulsified. [0148] (4) The above mixture is stirred and cooled to 45° C., aminomethyl propanol is added, stirred to dissolve, and then other components in Phase D are added, stirred and cooled to 30˜35° C.; [0149] (5) A lotion is obtained, whose pH value is adjusted to 5.5˜6.5, upon passing quality examination, the lotion filled in vessels. Comparative Product [0150] The comparative product used in the present invention is a skin care product available in the prior art, which has a composition as follows (portions by weight): [0000] PPG-3 Benzyl ether myristate      2~5 portions Polyglycerin-3 methylglucose distearate      2~5 portions Hydrogenated Poly(isobutylene)      2~5 portions Palmitoyl Pentapeptide-3      2~5 portions Polyglycerin-3 methylglucose distearate      1~3 portions Oat Extract      1~3 portions hexadecanol - octadecanol      1~3 portions Glycerin monosterate      1~3 portions bisabolol 0.1~0.5 portion Butcher's Broom Root Extract 0.1~0.3 portion Centella asiatica Extract 0.1~0.5 portion panthenol 0.1~0.5 portion Calendula officinalis L. Extract 0.1~0.5 portion Hydrolyzed yeast protein 0.1~0.5 portion Aesculus hippocastanum Extract 0.1~0.5 portion Monoammonium glycyrrhizinate 0.1~0.5 portion BOSWELLIA SERRATA Extract 0.1~0.3 portion carnosine 0.1~0.5 portion xanthan gum 0.1~0.5 portion Radix Ginseng Extract 0.1~0.5 portion Ganoderma lucidum Extract 0.1~0.5 portion Boswellia carteri Extract 0.1~0.5 portion Oligopeptide-1 0.1~0.5 portion preservatives 0.1~0.2 portion [0151] For all the embodiments described above, the three parts of the composition are separately prepared and stored in separate containers until being used by users. In use, first mix the powder part in the aqueous part in a weight ratio between 1:50 and 1:500, preferably 1:100, and apply the mixture to the skin under gentle massage. Then, the emulsion part (in an amount roughly equal to the mixture of the power and aqueous part) is applied to the skin. The product is to be applied twice a day in the morning and the evening, respectively. Testing Conducted and Effects Observed [0152] In order to confirm the intended effects of the present invention, testing was conducted on female volunteers who had various undesirable skin conditions or symptoms and voluntarily enrolled for the trial. For each particular skin conditions (see below), three groups of volunteers, with 50 or more in each group, were assigned to use the products of embodiment 1, embodiment 2 and comparative prior art (described above), respectively. For each of the following skin conditions, the products were applied to the facial skin twice a day for 4 weeks (about 3% volunteers terminated the use due to side effects during the 4-week trial period). The application of the product on facial skin was conducted in a manner that a person normally uses a cosmetic product. About one gram of the product was used each time with a ratio of 1:100:100 among the power part, aqueous part and emulsion part (first applying the mixture of power and aqueous parts and then applying the emulsion part with a gentle massage in between). At the end of each week during the trial, each volunteer was asked about what was her degree of satisfaction with the product on a scale from 1 to 5 and how effective she found the product on relieving a particular skin condition on a scale from 1 to 3 (1 means no effect, 2 means some effect, and 3 means significant effect). The following skin conditions/symptoms were tried: [0153] 1. Facial wrinkles/fine lines. The result was shown in FIG. 2( a ) . [0154] 2. Rough skin. The result was shown in FIG. 2( b ) . [0155] 3. Dry skin/dehydration. The result was shown in FIG. 2( c ) . [0156] 4. Flabby skin/lack of elasticity. The result was shown in FIG. 2( d ) . [0157] 5. Dull skin tone/lack of gloss. The result was shown in FIG. 2( e ) . [0158] 6. Large skin pore size. The result was shown in FIG. 2( f ) . [0159] 7. Variated skill colors/lack of color uniformity. The result was shown in FIG. 2( g ) . [0160] 8. Oily skin. The result was shown in FIG. 2( h ) . [0161] 9. Skin with colored spots. The result was shown in FIG. 2( i ) . [0162] 10. Pigment sediment. The result was shown in FIG. 2( j ) . [0163] 11. Scar left after acne. The result was shown in FIG. 2( k ) . [0164] Other skin conditions, such as, reddish-prone skin, couperose-prone skin, scurf-prone skin and allergic sensitive skin, were also tried but the data are not shown here as there were not enough volunteers enrolled for the trial. [0165] FIG. 1 is the summary of the overall satisfactory rate of each product by the participating volunteers (1, 2 and c refers to products of embodiment 1 embodiment 2 and the comparative prior art product, respectively). As can be seen from FIG. 1 , comparing with the existing product available in the art (c), both embodiments (1 and 2) of the present invention demonstrated a superior result. At the end of the 4 week trial, both received higher satisfactory rates, 3.81 and 3.58, respectively, comparing to 3.38 for the prior art product. More significantly, the longer the present invention product was used, the result was better. By comparison, the prior art product peaked at week 3 and continued use had a declined satisfaction. The data suggest that not only the products of the present invention have quicker and better effects from onset but also are better suited for long-term use. [0166] FIG. 2 shows the effects on specific skin conditions/symptoms tried. For example, FIG. 2( a ) relates to the condition of facial wrinkles and appearance of fine lines. The left-side curves show that volunteers in the embodiment 1 group (♦) rated the effectiveness at 1.29 (average) after the first week, 1.69 after the second week, 1.79 after the week and 1.90 after the fourth week. The corresponding data for the embodiment 1 group (▪) are 1.31, 1.49, 1.64 and 180 and for the prior art group (▴), the data are 1.23, 1.37, 1.58 and 1.67. For effectiveness rate, 1 means no effect, 2 means some effect, and 3 means significant effects. Understandably, for a cosmetic product, the effectiveness rarely reaches 3. The right-side table shows that Embodiment 1 has an onset time of 13.3 days, which refers to the average time when the volunteers observed at least some effects. The onset time is 13.5 days for Embodiment 2 and 15.3 days for the comparative product. In the Embodiment 1 group, 29% volunteers observed at least some effect (i.e., giving an effectiveness rate of either 2 or 3) at week 1, 62% at week 2, 69% at week 3 and 76% at week 4. The corresponding percentages for Embodiment 2 are 31%, 49%, 58% and 67%. For comparison, the data for the prior art product are 21%, 35%, 53% and 67%. Similar treads can be found in FIG. 2( b )-( k ) , and it shows that for all the skin conditions/symptoms tried, the products of the present invention had consistently achieved better results than the prior art comparative product in terms of the onset time, the percentage and the degree of effectiveness. [0167] Although not wishing to be bound to any particular theory, the inventors believe that the product of the present invention may achieve its beneficial effects on skin conditions by regulating the immunity and delaying the aging process of skin induced by the sun light. This mechanism was at least part of the consideration in selecting the various ingredients, many of which are derived from natural sources and used in the traditional medicine showing effects in regulating immunity. This may serve as a guideline in modifying the embodiments disclosed herewith and such modifications may achieve similar effects without departing from the spirit of the present invention. [0168] While there have been described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes, in the form and details of the embodiments illustrated, may be made by those skilled in the art without departing from the spirit of the invention. The invention is not limited by the embodiments described above which are presented as examples only but can be modified in various ways within the scope of protection defined by the appended patent claims

A skin care composition and product having beneficial effects on skin conditions/symptoms, such as reducing wrinkles and skin roughness and improving skin elasticity, etc. The composition has three separate parts: a powder part, an aqueous part and an emulsion part. The power part comprises Oligopeptide-1 and Ginseng saponin. The aqueous part comprises Glycyrrhiza glabra Root Extract, Artemisia capillaris Flower Extract, Radix Mori Albae Extract, Zizyphus jujuba Fruit Extract, Scutellaria baicalensis Root Extract, hydrolyzed rice protein and nicotinamide. The emulsion part comprises Bifida ferment lysate, creatine, carnosine, Glucosyl Hesperidin, Hexapeptide-3, Centella asiatica Extract, Coenzyme Q10 capsule, Opuntia Ficus - indica Stem Extract, Rhodiola rosea Extract, Saussurea Involucrata Extract, Panax notoginseng Root Extract and Angelica sinensis Extract capsule.

RELATED APPLICATIONS This application claims priority to Taiwan Application Serial Number 101129391, filed on Aug. 14, 2012, which is herein incorporated by reference. BACKGROUND 1. Field of Invention The present invention relates to a photosensitive resin composition, a spacer or a protective film formed by the aforementioned photosensitive resin composition, and a liquid crystal display device (LCD) including the aforementioned spacer or protective film. More particularly, the present invention relates to a photosensitive resin composition having excellent resolution and development adherence, a spacer or a protective film formed by the aforementioned photosensitive resin composition, and a LCD including the aforementioned spacer or protective film. 2. Description of Related Art In general, uneven surfaces generated from color-printed pixels and black matrixes on the surface of a color filter layer can be covered with a protective film thereon the surface of the color filter layer for planarization. However, during manufacturation of optical devices such as liquid crystal display devices or solid state imaging apparatus, there have to be treated by some processes under severe conditions. For example, a wiring electrode layer can be formed on a substrate surface by various methods of treating the substrate surface, for example, immersing the substrate surface into an acid solvent or alkaline solution, being sputtered on the substrate or the like. Such severe treatments can cause local corrosion or local high temperature. Therefore, it is necessary to cover protective films on the surfaces of these devices, so as to avoid the devices from being damaged during the manufacturation. In order to enable the protective film to resist damages of the aforementioned treatments, the protective film must have excellent adhesion to the substrate, as well as a surface with a high transparency, a high surface hardness and smoothness. Moreover, a protective film with high heat resistance and light resistance will not be deteriorated (such as color change, yellowing or whitening) after a long-time usage. Furthermore, it is also necessary for the protective film to have other characteristics such as good water resistance, chemical resistance, solvent resistance, acid resistance, alkaline resistance and the like. Additionally, for the prior art, in a color LCD in order to maintain a constant layer distance (e.g. intercellular space) between two substrates, polystyrene beads or silica beads, for example, are randomly sprayed on the whole substrate, in which the diameters of these beads are equal to the distance between the two substrates. However, since those sprayed beads are uneven in their positions and distribution density by the prior methods, the light from the backlight source is scattered due to the influence of the sprayed beads, and thus the contrast ratio of the display devices are further reduced. For the aforementioned reasons, a photosensitive composition used for a spacer has been developed by photolithography and it has become the mainstream of the industry. At first, the photosensitive composition used for the spacer is coated onto the substrate, and then a light mask with a specific shape is placed between the substrate and an exposure source, followed by being exposed and developed, so that a spacer can be formed. Based on the aforementioned method, the spacer can be formed on given positions except R, G and B pixels, so as to solve the problem of the prior art. The cell gap can also be controlled by the thickness of the coated photosensitive composition, so that the distance of the cell gap can be easily controlled with the advantage of high precision. Since the protective film or the spacer is formed on the color light filter or the substrate, the requirement for its transparency is extremely high. When such a protective film or spacer with poor transparency is used in the LCD, the brightness of the LCD will be insufficient, thereby affecting the display quality of the LCD. In order to improve the transparency of the protective film or spacer, a photosensitive composition used for the protective film is disclosed in the Japanese Patent Laid-Open Publication No. 2010-054561, which includes an alkali-soluble binder resin (A); a compound (B) containing vinyl unsaturated group(s); a photoinitiator (C); and a solvent (D). The combination equivalent weight of the unsaturated bonds in the compound (B) containing vinyl unsaturated group(s) is 90 to 450 g/eq, the number of unsaturated double bonds in one molecule of the compound (B) containing vinyl unsaturated group(s) is 2 to 4, and the weight-average molecular weight of the alkali-soluble binder resin (A) is 10,000 to 20,000. Additionally, a photosensitive composition is disclosed in the Japanese Patent Laid-Open Publication No. 2004-240241, which includes (A) a copolymer (A) of an ethylenically unsaturated carboxylic acid (anhydride), an ethylenically unsaturated compound containing an epoxy group(s), and other ethylenically unsaturated compounds; (B) a polymerizable compound having an ethylenically unsaturated group(s); and (C) a photopolymerization initiator represented by 2-butanedione-[4-(methylthio)phenyl]-2-(O-oxime acetate), 1,2-butanedione-1-(4-morpholinylphenyl)-2-(O-benzoyloxime), 1,2-octanedione-1-[4-(phenylthio)phenyl]-2-[O-(4-methylbenzoyl)oxime] or the like. However, although such a photosensitive composition can be used to manufacture a protective film or spacer with high transparency, the photosensitive composition has disadvantages of poor resolution and development adherence. Accordingly, it is necessary to develop a photosensitive resin composition used for a spacer or protective film with excellent resolution and development adherence, so as to solve various aforementioned problems of the conventional protective film or spacer. SUMMARY Therefore, an aspect of the present invention provides a photosensitive resin composition, which comprises an alkali-soluble resin (A), a compound (B) containing vinyl unsaturated group(s), a photoinitiator (C), ortho-naphthoquinone diazide sulfonic acid ester (D), a thermal initiator (E) and a solvent (F). Another aspect of the present invention provides a spacer, which has a pattern and is formed by subjecting the aforementioned photosensitive resin composition to sequentially pre-baking, exposing, developing and post-baking steps. A further aspect of the present invention provides a protective film, which has a pattern and is formed by subjecting the aforementioned photosensitive resin composition to sequentially pre-baking, exposing, developing and post-baking steps. Yet a further aspect of the present invention provides a LCD device, which includes the aforementioned spacer or protective film, so as to improve the disadvantages of the prior spacer or protective film with poor resolution and development adherence manufactured from conventional photosensitive resin compositions. The photosensitive resin composition of the present invention includes an alkali-soluble resin (A), a compound (B) containing vinyl unsaturated group(s), a photoinitiator (C), ortho-naphthoquinone diazide sulfonic acid ester (D), a thermal initiator (E) and a solvent (F), which are described in details as follows. It only should be noted that in the present invention, (meth)acrylic acid represents acrylic acid and/or methacrylic acid; similarly (meth)acrylic ester represents acrylic ester and/or methacrylate ester; and (meth)acryloyl represents acryloyl and/or methacryl. Alkali-Soluble Resin (A) The alkali-soluble resin (A) of the present invention refers to a resin that can be soluble in an alkaline aqueous solution without being limited to any specific structure. In a preferred embodiment of the present invention, the alkali-soluble resin (A) refers to a resin including a carboxylic group, a phenol-novolac resin and the like. Preferably, the alkali-soluble resin (A) is copolymerized from a compound (a1) of unsaturated carboxylic acid or unsaturated carboxylic anhydride, an unsaturated compound containing epoxy group(s) (a2) and/or other unsaturated compounds (a3) in a solvent in the presence of an appropriate polymerization initiator. 1. Compound (a1) of Unsaturated Carboxylic Acid or Unsaturated Carboxylic Anhydride The aforementioned compound (a1) of unsaturated carboxylic acid or unsaturated carboxylic anhydride refers to a compound containing the structure of carboxylic acid or carboxylic anhydride and unsaturated polymerizable bonds without being limited to any specific structure. The compound includes but is not limited to an unsaturated monocarboxylic acid compound, an unsaturated dicarboxylic acid compound, an unsaturated acid anhydride compound, an unsaturated polycyclic carboxylic acid compound, an unsaturated polycyclic dicarboxylic acid compound and an unsaturated polycyclic acid anhydride compound. Specific examples of the aforementioned unsaturated monocarboxylic acid compound are as below: (meth)acrylic acid, butenoic acid, α-chloracrylic acid, ethyl acrylate, cinnamic acid, 2-(meth)acryloyloxyethyl succinate monoester, 2-(meth)acryloyloxyethyl hexahydrophthalic acid ester, 2-(meth)acryloyloxyethyl phthalic acid ester and omega-carboxyl polycaprolactone polyol monoacrylate (trade name of ARONIX M-5300, manufactured by Toagosei Co., Ltd.). Specific examples of the aforementioned unsaturated dicarboxylic acid compound are as below: maleic acid, fumaric acid, mesaconic acid, itaconic acid and traconic acid. In an example of the present invention, the unsaturated dicarboxylic acid anhydride compound is the anhydride compound of the aforementioned unsaturated dicarboxylic acid compound. The specific examples of the aforementioned unsaturated polycyclic carboxylic acid compound are as below: 5-carboxyl bicyclo[2.2.1]hept-2-ene, 5-carboxyl-5-methylbicyclo[2.2.1]hept-2-ene, 5-carboxyl-5-ethylbicyclo[2.2.1]hept-2-ene, 5-carboxyl-6-methylbicyclo[2.2.1]hept-2-ene and 5-carboxyl-6-ethylbicyclo[2.2.1]hept-2-ene. The specific examples of the aforementioned unsaturated polycyclic dicarboxylic acid compound are as below: 5,6-dicarboxylic bicyclo[2.2.1]hept-2-ene. The aforementioned unsaturated polycyclic dicarboxylic acid anhydride compound is the anhydride compound of the aforementioned unsaturated polycyclic dicarboxylic acid compound. The preferred examples of the aforementioned compound (a1) of unsaturated carboxylic acid or unsaturated carboxylic anhydride are acrylic acid, methacrylic acid, maleic anhydride, 2-methacryloyloxyethyl succinate monoester and 2-methacryloyloxyethyl hexahydrophthalic acid. The compound (a1) of unsaturated carboxylic acid or unsaturated carboxylic anhydride can be used separately or with a mixture of a plurality of compounds (a1). Based on a total amount of the compound (a1) of unsaturated carboxylic acid or unsaturated carboxylic anhydride, the unsaturated compound containing epoxy group(s) (a2) and other unsaturated compounds (a3) as 100 parts by weight, preferably the amount of the compound (a1) of unsaturated carboxylic acid or unsaturated carboxylic anhydride is 5 to 50 parts by weight. 2. Unsaturated Compound Containing Epoxy Group(s) (a2) The aforementioned unsaturated compound containing epoxy group(s) (a2) may include but be not limited to (meth)acrylic ester compounds containing epoxy group(s), α-alkyl acrylate compounds containing epoxy group(s) and epoxypropyl ether compounds. Specific examples of the aforementioned (meth)acrylic ester compounds containing epoxy group(s) are as below: glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 6,7-epoxyheptyl (meth)acrylate, 3,4-epoxycyclohexyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate. Specific examples of the aforementioned α-alkyl acrylate compounds containing epoxy group(s) are as below: glycidyl α-ethacrylate, glycidyl α-n-propylacrylate, glycidyl α-n-butylacrylate and 6,7-epoxyheptyl α-ethacrylate. Specific examples of the aforementioned epoxypropyl ether compounds are as below: o-vinylbenzylglycidylether, m-vinylbenzylglycidylether and p-vinylbenzylglycidylether. The preferred examples of the aforementioned unsaturated compound containing epoxy group(s) (a2) are as below: glycidyl methacylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 6,7-epoxyheptyl acrylate, O-vinylbenzylglycidylether, m-vinylbenzylglycidylether and p-vinylbenzylglycidylether. The aforementioned unsaturated compound containing epoxy group(s) (a2) can be used separately or with a mixture of a plurality of the compounds (a2). Based on a total amount of the compound (a1) of unsaturated carboxylic acid or unsaturated carboxylic anhydride, the unsaturated compound containing epoxy group(s) (a2) and other unsaturated compounds (a3) as 100 parts by weight, preferably the amount of the unsaturated compound containing epoxy group(s) (a2) is 10 parts by weight to 70 parts by weight. 3. Other Unsaturated Compounds (a3) The aforementioned other unsaturated compounds (a3) may include but be not limited to alkyl (meth)acrylate, alicyclic (meth)acrylate, aryl (meth)acrylate, unsaturated dicarboxylic diester, hydroxyalkyl (meth)acrylate, polyether of (meth)acrylic esters, aromatic vinyl compounds and other unsaturated compounds except the aforementioned unsaturated compounds. The specific examples of the aforementioned alkyl (meth)acrylate are as below: methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, sec-butyl (meth)acrylate and tert-butyl (meth)acrylate. The specific examples of the aforementioned alicyclic (meth)acrylate are as below: cyclohexyl (meth)acrylate, 2-methylcyclohexyl (meth)acrylate, tricyclic[5.2.1.0 2,6 ]deca-8-yl (meth)acrylic ester (or referred to as dicyclopentanyl (meth)acrylate), dicyclopentyloxyethyl (meth)acrylate, isobornyl (meth)acrylate and tetrahydrofuranyl (meth)acrylate. The specific examples of the aforementioned aryl (meth)acrylate are as below: phenyl (meth)acrylate and benzyl (meth)acrylate. The specific examples of the aforementioned unsaturated dicarboxylic diester are as below: diethyl maleate, diethyl fumarate and diethyl itaconate. The specific examples of the aforementioned hydroxyalkyl (meth)acrylate are as below: 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. The specific examples of the aforementioned polyether of (meth)acrylic esters areas below: polyglycol mono(meth)acrylate and polypropylene glycol mono(meth)acrylate. The specific examples of the aforementioned aromatic vinyl compounds are as below: styrene monomer, α-methylstyrene, m-methylstyrene, p-methylstyrene and p-methoxy styrene. The specific examples of the aforementioned other unsaturated compounds are as below: acrylonitrile, methacrylonitrile, chloroethylene, vinylidene chloride, acrylamide, methacrylamide, vinyl acetate, 1,3-butadiene, isoprene, 2,3-dimethyl 1,3-butadiene, N-cyclohexyl maleimide, N-phenyl maleimide, N-benzyl maleimide, N-succinimide-3-maleimidobenzoic ester, N-succimide-4-maleimidobutyric ester, N-succinimide-6-maleimidocaproate, N-succinimide-3-maleimido propionic ester and N-(9-acridinyl) maleimide. The preferred examples of the aforementioned other unsaturated compounds (a3) are as below: methyl (meth)acrylate, butyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, tert-butyl (meth)acrylate, benzyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, styrene monomer and p-methoxy styrene. The aforementioned other unsaturated compounds (a3) can be used separately or with a mixture of a plurality of the compounds (a3). Based on a total amount of the compound (a1) of unsaturated carboxylic acid or unsaturated carboxylic anhydride, the unsaturated compound containing epoxy group(s) (a2) and other unsaturated compounds (a3) as 100 parts by weight, preferably the amount of the other unsaturated compounds (a3) is 0 parts by weight to 70 parts by weight. During manufacturing, the solvent used for the alkali-soluble resin (A) of the present invention may include but be not limited to alcohol, ether, glycol ether, glycolalkyl ether acetate, diethylene glycol, dipropylene glycol, propylene glycol monoalkyl ether, propylene glycol monoalkyl ether acetate, propylene glycol monoalkyl ether propionate, aromatic hydrocarbon, ketone and ester. The specific examples of the aforementioned alcohol are as below: methanol, ethanol, phenylcarbinol, 2-phenylethanol and 3-phenyl-1-propanol. The specific example of the aforementioned ether is tetrahydrofuran. The specific examples of the aforementioned glycol ether are as below: ethylene glycol monopropyl ether, ethylene glycol monomethyl ether and ethylene glycol monoethyl ether. The specific examples of the aforementioned glycolalkyl ether acetate are as below: glycol monobutyl ether acetate, glycol ether acetate and glycol monomethyl ether acetate. The specific examples of the aforementioned diethylene glycol are as below: diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether. The specific examples of the aforementioned dipropylene glycol are as below: dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether and dipropylene glycol ethyl methyl ether. The specific examples of the aforementioned propylene glycol monoalkyl ether are as below: propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether and propylene glycol monobutyl ether. The specific examples of the aforementioned propylene glycol monoalkyl ether propionate are as below: propylene glycol monomethyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate and propylene glycol butyl ether acetate. The specific examples of the aforementioned propylene glycol monoalkyl ether propionate are as below: propylene glycol monomethyl ether propionate, propylene glycol ethyl ether propionate, propylene glycol propyl ether propionate and propylene glycol butyl ether propionate. The specific examples of the aforementioned aromatic hydrocarbon are as below: methylbenzene and dimethylbenzene. The specific examples of the aforementioned ketone are as below: ethyl methyl ketone, cyclohexanone and diacetone alcohol. The specific examples of the aforementioned ester are as below: methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methpropionate, ethyl 2-hydroxy-2-methpropionate, methyl glycolate, ethyl glycolate, butyl glycolate, methyl lactate, propyl lactate, butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, butyl 3-hydroxypropionate, methyl 2-hydroxy-3-methbutyrate, methyl methoxylacetate, ethyl methoxylacetate, butyl methoxylacetate, methyl ethoxylacetate, ethyl ethoxylacetate, propyl ethoxylacetate, butyl ethoxylacetate, methyl propoxylacetate, ethyl propoxylacetate, propyl propoxylacetate, butyl propoxylacetate, methyl butoxyacetate, ethyl butoxyacetate, propyl butoxyacetate, butyl butoxyacetate, 3-methoxylbutyl acetate, methyl 2-methoxylpropionate, ethyl 2-methoxylpropionate, propyl 2-methoxylpropionate, butyl 2-methoxylpropionate, methyl 2-ethoxylpropionate, ethyl 2-ethoxylpropionate, propyl 2-ethoxylpropionate, butyl 2-ethoxylpropionate, methyl 2-butoxypropionate, ethyl 2-butoxypropionate, propyl 2-butoxypropionate, butyl 2-butoxypropionate, methyl 3-methoxylpropionate, ethyl 3-methoxylpropionate, propyl 3-methoxylpropionate, butyl 3-methoxylpropionate, methyl 3-ethoxylpropionate, ethyl 3-ethoxylpropionate, propyl 3-ethoxylpropionate, butyl 3-ethoxylpropionate, methyl 3-propoxylpropionate, ethyl 3-propoxylpropionate, propyl 3-propoxylpropionate, butyl 3-propoxylpropionate, methyl 3-butoxypropionate, ethyl 3-butoxypropionate, propyl 3-butoxypropionate and butyl 3-butoxypropionate. The preferred examples of the solvent used for the alkali-soluble resin (A) of the present invention during manufacturing are as below: diethylene glycol dimethyl ether and propylene glycol monomethyl ether acetate. The aforementioned solvent can be used separately or with a mixture of a plurality of the solvents. The specific examples Pfizer the polymerizing initiator used for the is alkali-soluble resin (A) of the present invention during manufacturing are azo compounds or peroxides. The specific examples of the aforementioned azo compounds are as below: 2,2′-azobis(isobutyronitrile), 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis(4-methoxyl-2,4-dimethylvaleronitrile), 2,2′-azobis(2-methyl butyronitrile), 4,4′-azobis(4-cyano valeric acid) and 2,2′-azobis(dimethyl-2-methylpropionate). The specific examples of the aforementioned peroxides are as below: dibenzoyl peroxide, dilauroyl peroxide, tert-butyl peroxypivalate, 1,1-di(tert-butylperoxy)cyclohexane and hydrogen peroxide. The aforementioned polymerizing initiator can be used separately or with a mixture of a plurality of the polymerizing initiators. The weight average module weight of the alkali-soluble resin (A) of the present invention is generally 3,000 to 100,000, preferably 4,000 to 80,000, and more preferably 5,000 to 60,000. The molecular weight of the alkali-soluble resin (A) of the present invention can be adjusted by using a single resin or using two or more resins with different molecular weights synergistically. Compound (B) Containing Vinyl Unsaturated Group(s) The compound (B) containing vinyl unsaturated group(s) of the present invention refers to a compound containing at least one vinyl unsaturated group. In the examples of the present invention, the compounds containing one vinyl unsaturated group are as below: acrylamide, (meth)acryloyl morpholine, 7-amino-3,7-dimethyloctylamine (meth)acrylate, isobutoxymethyl (meth)acrylamide, isobornyloxyethyl (meth)acrylate, isobornyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, ethyl diethylene glycol (meth)acrylate, tert-octyl (meth)acrylamide, dipropyl ketone (meth)acrylamide, dimethylamino (meth)acrylate, dodecyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, N,N-dimethyl (meth)acrylamide, tetrachlorobenzene (meth)acrylate, 2-tetrachlorophenoxylethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, tetrabromobenzene (meth)acrylate, 2-tetrabromophenoxylethyl (meth)acrylate, trichlorophenoxylethyl (meth)acrylate, tribromobenzene (meth)acrylate, 2-tribromophenoxylethyl (meth)acrylate, 2-ethoxyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, vinylcaprolactam, N-vinyl pyrrolidone, phenoxyethyl (meth)acrylate, pentachlorobenzene (meth)acrylate, pentabromobenzene (meth)acrylate, glycerol polymono(meth)acrylate, propanediol polymono(meth)acrylate, borneol (meth)acrylate, diethylene glycol monoethyl ether (meth)acrylate, butyl 3-methoxyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate ester, omega-carboxypolycaprolactone monoacrylate, ARONIX M-101, M-111, M-114 and M-5300 (manufactured by Toagosei Co., Ltd), KAYARAD TC-110S and TC-120S (manufactured by Nippon Kayaku), Viscoat 158 and 2311 (manufactured by Osaka Organic Chemical Industry Ltd.). In the examples of the present invention, the compounds containing two or more vinyl unsaturated groups are as below: diethylene glycol di(meth)acrylate, dicyclopentene di(meth)acrylate, triethylene glycol diacrylate, tetraethylene glycol di(meth)acrylate, tri(2-ethoxyl)isocyanate di(meth)acrylate, tri(2-ethoxyl)isocyanate tri(meth)acrylate, caprolactone modified tri(2-ethoxyl)isocyanate tri(meth)acrylate, trihydroxymethylpropyl tri(meth)acrylate, ethylene oxide (hereinafter abbreviated as EO) modified trihydroxymethylpropyl tri(meth)acrylate, propylene oxide (hereinafter abbreviated as PO) modified trihydroxymethylpropyl tri(meth)acrylate, triglycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, di(alcoholphenoxyl)fluorine di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, polyester di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, EO modified dipentaerythritol hexa(meth)acrylate, EO modified dipentaerythritol penta(meth)acrylate, bistrimethylolpropyl tetra(meth)acrylate, EO modified bisphenol A di(meth)acrylate, PO modified bisphenol A di(meth)acrylate, EO modified hydrogenated bisphenol A di(meth)acrylate, PO modified hydrogenated bisphenol A di(meth)acrylate, PO modified glycerol triacrylate, EO modified bisphenol F di(meth)acrylate, phenolic polyglycidyl ether (meth)acrylate, tri(2-(meth)acryloyloxyethyl) phosphate ARONIX M-210, M-240, M-6200, M-309, M-400, M-405, M-450, M-7100, M-8030 and M-8060; TO-1450 (manufactured by Toagosei Co., Ltd.), KAYARAD HDDA, HX-220, R-604, DPHA, TMPTA, DPCA-20, DPCA-30, DPCA-60, DPCA-120 (manufactured by Nippon Kayaku), Viscoat 260, 312, 335H.P., 295, 300, 360, GPT, 3PA, 400 (manufactured by Osaka Organic Chemical Industry Ltd.). The compound containing nine or more vinyl unsaturated groups is: a compound having a structure of ethylene straight chain and cycloaliphatic ring, such as a polyurethane acrylate polymerized from a compound containing more than two isocyanate groups and a (meth)acrylate compound which has one or more hydroxyl groups and three, four or five functional groups per molecular. The specific examples of the compound are New frontier R-1150 (manufactured by Daiichi Sankyo Co., Ltd.) and KAYARAD DPHA-40H (manufactured by Nippon Kayaku). Preferably, the compound (B) containing the vinyl unsaturated groups is trimethylolpropane triacrylate, caprolactone modified trimethylolpropane triacrylate, PO modified trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, dipentaerythritol tetraacrylate, caprolactone modified dipentaerythritol hexaacrylate, bistrimethylolpropyl tetra(meth)acrylate, PO modified glycerol triacrylate. These compound (B) containing the vinyl unsaturated groups can be used separately or with a mixture of a plurality of the compounds (B). The amount of the compound (B) containing the vinyl unsaturated group(s) of the present invention can be adjusted according to requirements. In an example of the present invention, based on the amount of the alkali-soluble resin (A) as 100 parts by weight, the amount of the compound (B) containing the vinyl unsaturated group(s) of the present invention is 20 parts by weight to 200 parts by weight, preferably 25 parts by weight to 190 parts by weight, and more preferably 30 parts by weight to 180 parts by weight. Photoinitiator (C) The photoinitiator (C) of the present invention is subjected to no specific limitation, and in an example of the present invention the photoinitiator (C) includes O-acyloxime photoinitiators, triazine photoinitiators, acetophenone compounds, biimidazole compounds, benzophenone compounds, α-diketone compounds, ketol compounds, ketol ether compounds, acyl phosphine oxide compounds, quinone compounds, compounds containing halogens and peroxides. The specific examples of the aforementioned O-acyloxime photoinitiators are 1-[4-(phenylthio)phenyl]-heptane-1,2-diketone 2-(O-benzoyloxime), 1-[4-(phenylthio)phenyl]-octane-1,2-diketone 2-(O-benzoyloxime), 1-[4-(benzoyl)phenyl]-heptane-1,2-diketone 2-(O-benzoyloxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-ethyl ketone 1-(O-acetaldoxime), 1-[9-ethyl-6-(3-methylbenzoyl)-9H-carbazole-3-yl]-ethyl ketone 1-(O-acetaldoxime), 1-[9-ethyl-6-benzoyl-9H-carbazole-3-yl]-ethyl ketone 1-(O-acetaldoxime), ethyl ketone-1-[9-ethyl-6-(2-methyl-4-tetrahydrofuranylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetaldoxime), ethyl ketone-1-[9-ethyl-6-(2-methyl-4-tetrahydropyranylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetaldoxime), ethyl ketone-1-[9-ethyl-6-(2-methyl-5-tetrahydrofuranylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetaldoxime), ethyl ketone-1-[9-ethyl-6-(2-methyl-5-tetrahydropyranylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetaldoxime), ethyl ketone-1-[9-ethyl-6-(2-methyl-4-methoxyltetrahydrofuranylmethoxybenzoyl)-9H-carbazole-3-yl]-1-(O-acetaldoxime), ethyl ketone-1-[9-ethyl-6-(2-methyl-4-methoxyltetrahydropyranylmethoxybenzoyl)-9H-carbazole-3-yl]-1-(O-acetaldoxime), ethyl ketone-1-[9-ethyl-6-(2-methyl-5-methoxytetrahydrofuranylmethoxybenzoyl)-9H-carbazole-3-yl]-1-(O-acetaldoxime), ethyl ketone-1-[9-ethyl-6-(2-methyl-5-methoxyltetrahydropyranylmethoxybenzoyl)-9H-carbazole-3-yl]-1-(O-acetaldoxime), ethyl ketone-1-[9-ethyl-6-{2-methyl-4-(2,2-dimethyl-1,3-dioxolan)benzoyl}-9H-carbazole-3-yl]-1-(o-acetaldoxime) and ethyl ketone-1-[9-ethyl-6-{2-methyl-4-(2,2-dimethyl-1,3-dioxolan)methoxylbenzoyl}-9H-carbazole-3-yl]-1-(O-acetaldoxime). The aforementioned O-acyloxime photoinitiators can be used separately or with a mixture of a plurality of the O-acyloxime photoinitiators. The aforementioned O-acyloxime photoinitiator is preferably 1-[4-(phenylthio)phenyl]-octane-1,2-diketone 2-(o-benzoylbenzoyloxime), 1-[9-ethyl-(2-benzoylmethybenzoyl)-9H-cabazole-3-yl]-ethyl ketone 1-(O-acetaldoxime), ethyl ketone-1-[9-ethyl-6-(2-methyl-4-tetrahydrofuranmethoxylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetaldoxime) and ethyl ketone-1-[9-ethyl-6-{2-methyl-4-(2,2-dimethyl-1,3-dioxolan)methoxylbenzoyl}-9H-carbazole-3-yl]-1-(O-acetaldoxime). The specific examples of the triazine photoinitiator of the present invention are as below: vinyl-halomethyl-s-triazine compounds, 2-(naphtho-1-yl)-4,6-bis-halomethyl-s-triazine compounds and 4-(p-aminophenyl)-2,6-bis-halomethyl-s-triazine compounds. The specific examples of the vinyl-halomethyl-s-triazine compound areas below: 2,4-bis(trichloromethyl)-6-p-methoxylmethoxy styrene-s-triazine, 2,4-bis(trichloromethyl)-3-(1-p-dimethylaminophenyl-1,3-bivinyl)-s-triazine and 2-trichloromethyl-3-amino-6-p-methoxylmethoxy styrene-s-triazine. The specific examples of the 2-(naphtho-1-yl)-4,6-bis-halomethyl-s-triazine compound are as below: 2-(naphtho-1-yl)-4,6-bis-trichloromethyl-s-triazine, 2-(4-methoxylmethoxyl-naphtho-1-yl)-4,6-bis-trichloromethyl-s-triazine, 2-(4-ethoxyl-naphtho-1-yl)-4,6-bis-trichloromethyl-s-triazine, 2-(4-butoxy-naphtho-1-yl)-4,6-bis-trichloromethyl-s-triazine, 2-[4-(2-methoxyl ethylmethoxyl)-naphtho-1-yl]-4,6-bis-trichloromethyl-s-triazine, 2-[4-(2-ethoxy]ethyl)-naphtho-1-yl-4,6-bis-trichloromethyl-s-triazine, 2-[4-(2-butoxylethyl)-naphtho-1-yl]-4,6-bis-trichloromethyl-s-triazine, 2-(2-methoxyl-naphtho-1-yl)-4,6-bis-trichloromethyl-s-triazine, 2-(6-methoxyl-5-methyl-naphtho-2-yl)-4,6-bis-trichloromethyl-s-triazine, 2-(6-methoxyl-naphtho-2-yl)-4,6-bis-trichloromethyl-s-triazine, 2-(5-methoxyl-naphtho-1-yl)-4,6-bis-trichloromethyl-s-triazine, 2-(4,7-dimethoxyl-naphtho-1-yl)-4,6-bis-trichloromethyl-s-triazine and 2-(4,5-dimethoxyl-naphtho-1-yl)-4,6-bis-trichloromethyl-s-triazine. The specific examples of the 4-(p-aminophenyl)-2,6-di-halomethyl-s-triazine are as below: 4-[p-N,N-di(carbonylethoxycarbonylmethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[o-methyl-p-N,N-di(carbonylethoxycarbonylmethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[p-N,N-di(chloroethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[o-methyl-p-N,N-di(chloroethy)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-(p-N-chloroethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(p-N-carbonylethoxycarbonylmethylaminophenyl)-2,6-bis(trichloromethyl)-s-tri azine, 4-[p-N,N-di(phenyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-(p-N-chloroethylcarbonylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-[p-N-(p-methoxylphenyl)carbonylaminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[m-N,N-di(carbonylethoxycarbonylmethyl)aminophenyl]-2,6-bis(trichloromethyl 4)-s-triazine, 4-[m-bromo-p-N,N-di(carbonylethoxycarbonylmethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[m-chloro-p-N,N-di(carbonylethoxycarbonylmethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[m-fluoro-p-N,N-di(carbonylethoxycarbonylmethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[o-bromo-p-N,N-di(carbonylethoxycarbonylmethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[o-chloro-p-N,N-di(carbonylethoxycarbonylmethyl)aminophenyl-2,6-bis(trichloromethyl)-s-triazine, 4-o-fluoro-p-N,N-di(carbonylethoxycarbonylmethyl)aminophenyl-2,6-bis(trichloromethyl)-s-triazine, 4-[o-bromo-p-N,N-di(chloroethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[o-chlor-P—N,N-di(chloroethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[o-fluoro-p-N,N-di(chloroethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[m-bromo-p-N,N-di(chloroethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[m-chloro-p-N,N-di(chloroethyl)aminophenyl]2,6-bis(tricholormethyl)-s-triazine, 4-[m-chloro-p-N,N-di(chloroethyl)aminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-[m-fluoro-p-N-carbonylethoxycarbonylmethylaminophenyl]-2,6-bis(trichloromethyl)-s-triazine, 4-(m-bromo-p-N-carbonylethoxycarbonylmethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(m-cloro-p-N-carbonylethoxycarbonylmethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(m-flouro-N-carbonyethoxycarbonymethyaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(o-bromo-p-N-carbonylethoxycarbonylmethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(m-cloro-p-N-carbonylethoxycarbonylmethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(o-fluoro-p-N-carbonylethoxycarbonylmethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(m-bromo-p-N-chloroethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(m-chloro-p-N-chloroethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(m-fluoro-p-N-chloroethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(o-bromo-p-N-chloroethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(o-chloro-p-N-chloroethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine, 4-(o-fluoro-p-N-chloroethylaminophenyl)-2,6-bis(trichloromethyl)-s-triazine and 2,4-bis(trichloromethyl)-6-[3-bromo-4-[N,N-di(carbonylethoxycarbonylmethyl)amido]phenyl]-1,3,5-triazine. The aforementioned triazine photoinitiator can be used separately or with a mixture of a plurality of the triazine photoinitiators. The triazine photoinitiator is preferably: 4-[m-bromo-P—N,N-di(ethoxylcarbonylmethoxycarbonylmethyl)aminophenyl]-2,6-di(chlorotrichloromethyl)-s-triazine and 2,4-bis(chlorotrichloromethyl)-6-P-methoxylmethoxy styrene-s-triazine. The specific examples of the acetophenone compounds are as below: p-dimethylamine acetophenone, α,α′-dimethoxyl azoxy acetophenone, 2,2′-dimethyl-2-phenyl acetophenone, p-methoxyl acetophenone, 2-methyl-1-[4-(methylthio) phenyl]-2-morpholino-1-propanone and 2-benzyl-2-N,N-dimethylamine-1-(4-morpholinophenyl)-1-butanone. The phenethyl ketone compound can be used separately or with a mixture of a plurality of the phenethyl ketone compounds. The phenethyl ketone compound is preferably: 2-methyl-1-[4-(methylthio) phenyl]-2-morpholino-1-propanone and 2-benzyl-2-N,N-dimethylamine-1-(4-morpholinophenyl)-1-butanone. The examples of the biimidazole compounds are as below: 2,2′-bis(o-chlorophenyl)-4,4′,5,5′-tetraphenylbiimidazole, 2,2′-bis(o-fluorophenyl)-4,4′,5,5′-tetraphenylbiimidazole, 2,2′-bis(o-methylphenyl)-4,4′,5,5′-tetraphenylbiimidazole, 2,2′-bis(o-methoxylphenyl)-4,4′,5,5′-tetraphenylbiimidazole, 2,2′-bis(o-ethylphenyl)-4,4′,5,5′-tetraphenylbiimidazole, 2,2′-bis(p-methoxylphenyl)-4,4′,5,5′-tetraphenylbiimidazole, 2,2′-bis(2,2′,4,4′-tetramethoxylphenyl)-4,4′,5,5′-tetraphenylbiimidazole and 2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetraphenylbiimidazole, 2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenylbiimidazole. The biimidazole compound can be used separately or with a mixture of the biimidazole compounds according to requirements, and the biimidazole compound is preferably 2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenylbiimidazole. The specific examples of the benzophenone compounds are as below: thioxanthone, 2,4-diethylthioxanthone, thioxanthone-4-sulphone, benzophenone, 4,4′-bis(dimethylamine)benzophenone and 4,4′-bis(diethylamino)benzophenone. The benzophenone compound can be used separately or with a mixture of the benzophenone compounds according to requirements, and the benzophenone compound is preferably 4,4′-bis(diethylamino)benzophenone. The specific examples of the α-diketone compounds are as below: benzil, acetyl group; the specific example of the ketol compound is benzoin; the specific examples of the ketol ether compounds are as below: benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether; the specific examples of the acyl phosphine oxide compounds are as below: 2,4,6-trimethylbenzoyl diphenylphosphine oxide and bis-(2,6-dimethoxylbenzoyl)-2,4,4-trimethylphenyl phosphine oxide; the specific examples of the quinone compounds are as below: anthraquinone and 1,4-naphthaquinone; the specific examples of the compounds containing halogens are as below: phenacyl chloride, tribromomethyl phenyl sulfone and tri(trichloromethyl)-s-triazine; and the specific example of the peroxide is bis-tert-butyl peroxide. The aforementioned compound can be used separately or with a mixture of a plurality of the compounds according to the requirements. The amount of the photoinitiator (C) of the present invention can be adjusted according to requirements, and in an example of the present invention, based on the amount of the compound (B) containing vinyl unsaturated group(s) as 100 parts by weight, the amount of the photoinitiator (C) is 10 parts by weight to 80 parts by weight, preferably 12 parts by weight to 75 parts by weight, and more preferably 15 parts by weight to 70 parts by weight. Ortho-Naphthoquinone Diazide Sulfonic Acid Ester (D); The ortho-naphthoquinone diazide sulfonic acid ester (D) of the present invention is subjected to no specific limitation, and a generally used ortho-naphthoquinone diazide sulfonic acid ester (D) can be used. The ortho-naphthoquinone diazide sulfonic acid ester (D) may be a carboxylate that is completely or partially esterified. Preferably, the ortho-naphthoquinone diazide sulfonic acid ester (D) is prepared through the reaction between ortho-naphthoquinone diazide sulfonic acid or the salt thereof and a hydroxyl compound. Preferably, the ortho-naphthoquinone diazide sulfonic acid ester (D) is prepared through the reaction between the ortho-naphthoquinone diazide sulfonic acid or the salt thereof and a multihydroxyl compound. The aforementioned ortho-naphthoquinone diazide sulfonic acid may include but be not limited to ortho-naphthoquinone diazide-4-sulfonic acid, ortho-naphthoquinone diazide-5-sulfonic acid and ortho-naphthoquinone diazide-6-sulfonic acid. The salt of the aforementioned ortho-naphthoquinone diazide sulfonic acid may include but be not limited to ortho-naphthoquinone diazide halosulphonate. The aforementioned hydroxyl compound can be used separately or with a mixture of a plurality of the hydroxyl compounds, and the hydroxyl compound may include but be not limited to: (1) Hydroxybenzophenone compound: The specific examples of the hydroxybenzophenone compound may include but be not limited to 2,3,4-trihydroxybenzophenone, 2,4,4′-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, 2,3,4,4′-tetrahydroxy benzophenone, 2,4,2′,4′-tetrahydroxy benzophenone, 2,4,6,3′,4′-pentahydroxy benzophenone, 2,3,4,2′,4′-pentahydroxy benzophenone, 2,3,4,2′,5′-pentahydroxy benzophenone, 2,4,5,3′,5′-pentahydroxy benzophenone and 2,3,4,3′,4′,5′-hexahydroxy benzophenone. (2) The hydroxyaryl compound may include but be not limited to the hydroxyaryl compound of the formula (I) below: In the formula (I), R 1 -R 3 represent hydrogen atoms or alkyl groups of C 1 -C 6 ; R 4 -R 9 represent hydrogen atoms, halogen atoms, alkyl groups of C 1 -C 6 , alkoxy groups of C 1 -C 8 , alkenyl groups of C 1 -C 8 or cycloalkyl groups; R 10 -R 11 represent hydrogen atoms, halogen atoms and alkyl groups of C 1 -C 6 ; x, y and z represent integers 1 to 3; and n represents 0 or 1. The specific examples of the hydroxyaryl compound of the formula (I) above may include but be not limited to tris(4-hydroxy phenyl)methane, bis(4-hydroxy-3,5-dimethylphenyl)-4-hydroxy phenyl methane, bis(4-hydroxy-3,5-dimethylphenyl)-3-hydroxy phenyl methane, bis(4-hydroxy-3,5-dimethylphenyl)-2-hydroxy phenyl methane, bis(4-hydroxy-2,5-dimethylphenyl)-4-hydroxyphenyl methane, bis(4-hydroxy-2,5-dimethylphenyl)-3-hydroxyphenyl methane, bis(4-hydroxy-2,5-dimethylphenyl)-2-hydroxyphenyl methane, bis(4-hydroxy-3,5-dimethylphenyl)-3,4-dihydroxy phenyl methane, bis(4-hydroxy-2,5-dimethylphenyl)-3,4-dihydroxphenyl methane, bis(4-hydroxy-3,5-dimethylphenyl)-2,4-dihydroxyphenyl methane, bis(4-hydroxy-2,5-dimethylphenyl)-2,4-dihydroxyphenyl methane, bis(4-hydroxyphenyl)-3-methoxyl-4-hydroxyphenyl methane, bis(3-cyclohexyl-4-hydroxyphenyl)-3-hydroxyphenyl methane, bis(3-cyclohexyl-4-hydroxyphenyl)-2-hydroxyphenyl methane, bis(3-cyclohexyl-4-hydroxyphenyl)-4-hydroxy phenyl methane, bis(3-cyclohexyl-4-hydroxy-6-methylphenyl)-2-hydroxy phenyl methane, bis(3-cyclohexyl-4-hydroxy-6-methylphenyl)-3-hydroxy phenyl methane, bis(3-cyclohexyl-4-hydroxy-6-methylphenyl)-4-hydroxy phenyl methane, bis(3-cyclohexyl-4-hydroxy-6-methylphenyl)-3,4-dihydroxyphenyl methane, bis(3-cyclohexyl-6-hydroxy phenyl)-3-hydroxy phenyl methane, bis(3-cyclohexyl-6-hydroxy phenyl)-4-hydroxy phenyl methane, bis(3-cyclohexyl-6-hydroxyphenyl)-2-hydroxy phenyl methane, bis(3-cyclohexyl-6-hydroxy-4-methylphenyl)-2-hydroxy phenyl methane, bis(3-cyclohexyl-6-hydroxy-4-methylphenyl)-4-hydroxy phenyl methane, bis(3-cyclohexyl-6-hydroxy-4-methylphenyl)-3,4-dihydroxy phenyl methane, 1-[1-(4-hydroxy phenyl)isopropyl]-4-[1,1-bis(4-hydroxy phenyl)ethyl]benzene and 1-[1-(3-methyl-4-hydroxy phenyl)isopropyl]-4-[1,1-bis(3-methyl-4-hydroxy phenyl)ethyl]benzene. (3) (Hydroxy phenyl)hydrocarbon compound, the (hydroxy phenyl)hydrocarbon compound may include but be not limited to the (hydroxy phenyl)hydrocarbon compound of the formula (II) below: In the formula (II), R 12 to R 13 represent hydrogen atoms or alkyl groups of C 1 -C 8 , and p and q represent integers 1 to 3. The specific examples of the (hydroxy phenyl)hydrocarbon compound of the formula (II) above may include but be not limited 2-(2,3,4-trihydroxyphenyl)-2-(2′,3′,4′-trihydroxyphenyl)propane, 2-(2,4-dihydroxyphenyl)-2-(2′,4′-dihydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(4′-hydroxyphenyl)propane, bis(2,3,4-trihydroxyphenyl)methane and bis(2,4-dihydroxyphenyl)methane. (4) Other aromatic hydroxyl compounds: The specific examples of the other aromatic hydroxyl compounds may include but be not limited to phenol, metoxyphenol, xylenol, benzenediol, bisphenol A, naphthol, 0 benzenediol, 1,2,3-benzenetriol methyl ether, 1,2,3-benzenetriol-1,3-dimethyl ether, 3,4,5-trihydroxybenzoic acid and completely or partially esterified 3,4,5-trihydroxybenzoic acid, 4,4′-[1-[4-[−1-(4-hydroxy phenyl)-1-Methylethyl]phenyl]ethylene]bisphenol. Preferably, the aforementioned hydroxyl compound is selected from a group consisting of 4,4′-[1-[4-[−1-(4-hydroxy phenyl)-1-Methylethyl]phenyl]ethylene]bisphenol, 2,3,4-benzophenone trihydroxybenzophenone, 2,3,4,4′-tetrahydroxy benzophenone, 2-(2,3,4-trihydroxyphenyl)-2-(2′,3′,4′-trihydroxyphenyl)propane and any combination thereof. The aforementioned reaction between the ortho-naphthoquinone diazide sulfonic acid or the salt thereof and the hydroxyl compound are often performed in organic solution mediums such as dioxane, N-pyrrolidone and acetamide, and meanwhile it is helpful to react in the presence of alkaline condensing agents such as trolamine, alkali metal carbonates or alkali metal hydrogen carbonates. Preferably, the esterification degree of the aforementioned ortho-naphthoquinone diazide sulfonic acid ester (D) is above 50%. That is, when the total amount of hydroxyl groups in the aforementioned hydroxyl compound is calculated as 100 mol %, the esterification reaction is performed between above 50 mol % hydroxyl groups of the hydroxyl compound and the O naphthoquinone diazide sulfonic acid or the salt thereof. More preferably, the esterification degree of the naphthoquinone diazide compound (B) is above 60%. Based on the total amount of the alkali-soluble resin (A) as 100 parts by weight, the amount of the ortho-naphthoquinone diazide sulfonic acid ester (D) falls in a range 0.2 parts by weight to 15 parts by weight, preferably 0.3 parts by weight to 10 parts by weight, and more preferably 0.4 parts by weight to 6 parts by weight. It should be illustrated herein that the ortho-naphthoquinone diazide sulfonic acid ester (D) can increase the resolution of the spacer or protective film formed during the subsequent processes of the photosensitive resin composition of the present invention. If the ortho-naphthoquinone diazide sulfonic acid ester (D) is not used, the resulted spacer or protective film formed during the subsequent processes of the photosensitive resin composition will have a poor resolution. Thermal Initiator (E) The thermal initiator (E) of the present invention includes but is not limited to azo compounds, peroxides and hydrogen peroxide compounds. The specific examples of the aforementioned azo compounds may include but be not limited to 2,2′-azobis(isobutyronitrile), 2,2′-azobis(2-methyl butyronitrile), 1,1′-azobis(cyclohexane-1-carbonitrile), 2,2′-azobis(2,4-dimethylvaleronitrile, 1-[(1-cyano-1-methylethyl)azo]formamide, 2,2-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide, 2,2′-azobis[N-(2-propenyl)-2-methylpropionamide, 2,2′-azobis[N-(2-propenyl)-2-ethyl propionamide, 2,2′-azobis(N-butyl-2-methylpropionamide), 2,2′-azobis(N-cyclohexyl-2-methyl propionamide), 2,2′-azobis(dimethyl-2-methyl propionamide), 2,2′-azobis(dimethyl-2-methylpropionate) or 2,2′-azobis(2,4,4-trimethyl pentene). The specific examples of the aforementioned peroxides may include but be not limited to mixtures of benzoyl peroxide, peroxy bis(tert-butyl), diisobutyryl peroxide, cumyl peroxyneodecanoate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, di(4-t-butyl cyclohexyl) peroxydicarbonate, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, di(2-ethoxy-ethyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, t-hexyl peroxyneodecanoate, dimethoxybutyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, di(3,5,5-trimethyl hexanoyl) peroxide, di-n-octanoyl peroxide, dilauroyl peroxide, distearoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, t-butylperoxy-2-ethylhexanoate, dibenzoyl peroxide, t-butyl peroxyisobutyrate, 1,1-di(t-butylperoxy)-2-methylcyclohexane, 1,1-di(t-hexyl peroxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-hexyl peroxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, 2,2-di[4,4-di(t-butylperoxy)cyclohexyl]propane, t-hexyl peroxy isopropyl monocarbonate, t-butylperoxy maleate, t-butyl peroxy-3,5,5-trimethyl hexanoate, t-butyl peroxy laurate, 2,5-dimethyl-2,5-di-(3-methyl benzoyl peroxy)hexane, t-butyl peroxy isopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxy benzoate, 2,5-dimethyl-2,5-di(benzoyl peroxy)hexane, t-butyl peroxy acetate, 2,2-di(t-butylperoxy) butane, t-butyl peroxy benzoate, n-butyl-4,4-di(t-butylperoxy) valerate, di(2-t-butyl peroxy isopropyl)benzene, dicumyl peroxide, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di(t-butyl peroxy) hexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy) hexyne-3, t-butyl trimethylsilyl peroxide, di(3-methylbenzoyl) peroxidebenzoyl (3-methylbenzoyl) peroxide and dibenzoyl peroxide. The specific examples of the aforementioned hydrogen peroxide compounds may include but be not limited to p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethyl butyl hydroperoxide, cumene hydroperoxide and t-butyl hydroperoxide. Preferably, the specific examples of the thermal initiator (E) may include but be not limited to 2,2′-azobis(isobutyronitrile), 2,2′-azobis(2-methyl butyronitrile), 2,2′-azobis(2,4-dimethylvaleronitrile, peroxide diisobutyryloxy, dibenzoyl peroxide, t-butylperoxy isobutyrate, isopropylbenzene hydroperoxide, cumyl peroxyneodecanoate, p-menthane hydroperoxide or diisopropylbenzene hydroperoxide. The thermal initiator (E) can be used separately or with a mixture of a plurality of thermal initiators (E). Based on the total amount of the alkali-soluble resin (A) as 100 parts by weight, the amount of the thermal initiator (E) is 0.2 parts by weight to 10 parts by weight, preferably 0.3 parts by weight to 9 parts by weight, and more preferably 0.4 parts by weight to 8 parts by weight. It should be supplemented that the thermal initiator (E) can increase the adherence of the photosensitive resin composition of the present invention during the pre-baking process. If the thermal initiator (E) is not used, the resulted photosensitive resin composition will have poor adherence after being developed. Solvent (F) The solvent (F) of the present invention can be dissolved completely with other organic compositions, and the volatility of the solvent (F) should be that the solvent (F) can be evaporated from the dispersion liquid with little heat under normal pressure. Therefore, a solvent with a boiling point below 150° C. under normal pressure is used mostly. The appropriate solvent (F) includes aromatics, such as benzene, methylbenzene and dimethylbenzene; alcohols, such as methanol and ethanol; ethers, such as ethylene glycol monopropyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, esters, such as glycol monomethyl ether acetate, glycol ether acetate, propylene glycol monomethyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, ethyl 3-ethoxylpropionate; and ketones such as ethylmethyl ketone and acetone. It is preferably to use the diethylene glycol dimethyl ether, the propylene glycol monomethyl ether acetate and the ethyl 3-ethoxylpropionate cooperatively, which leads to an excellent storage stability of the photosensitive resin composition. Based on the total amount of the alkali-soluble resin (A) as 100 parts by weight, the amount of the solvent (F) is 500 parts by weight to 3000 parts by weight, preferably 500 parts by weight to 2500 parts by weight, and more preferably 500 parts by weight to 2000 parts by weight. Additives (G) Additionally, the photosensitive resin composition of the present invention can be further added with additives (G) according you the required physical and chemical characteristics, and the selection of the additives (G) can be made by those of ordinary skills in the art. In an example of the present invention, the additive (G) may be a loading agent, polymers except the alkali-soluble resin (A), ultraviolet light absorber, anti-agglutinate, surfactant, adhesion accelerator, storage stabilizer or heat-resistance promoter. The specific examples of the aforementioned loading agent are as below: glass and aluminum. The specific examples of the aforementioned polymers except the alkali-soluble resin (A) are as below: polyvinyl alcohol, polyethylene glycol monoalkyl ether, Polyfluoro alkyl acrylate. The specific examples of the aforementioned ultraviolet light absorber are as below: 2-(3-t-butyl-5-methyl-2-hydroxy phenyl)-5-chlorophenyl nitrine and alkoxy benzophenone; and the anti-agglutinant is polyacrylate sodium. The aforementioned surfactant can facilitate the coating ability of the photosensitive resin composition of the present invention, and the surfactant may include but be not limited to a fluorine-containing surfactant or a silicone surfactant. The aforementioned fluorine-containing surfactant at least includes fluorinated alkyl or fluorinated thiazolinyl at the end, main chain and branch chain thereof, and the specific examples thereof are as below: 1,1,2,2-tetrafluoropropyl)ether, 1,1,2,2-tetrafluoro octylhexyl ether, octaethylene glycol di(1,1,2,2-tetrafluorobutyl)ether, hoxaethylene glycol (1,1,2,2,3,3-hexafluoropentyl)ether, octapropanediol di(1,1,2,2-tetrafluorobutyl)ether, hoxapropanediol (1,1,2,2,3,3-hexafluoropentyl)ether, perfluoro sodium dodecyl sulfate, 1,1,2,2,8,8,9,9,10,10-Perfluorododecane, 1,1,2,2,3,3-hexafluorodecane, fluothane benzene sulfonate, fluothane sodium phosphate, fluothane carboxylic sodium, fluothane polyethenoxy ether, dipropanetriol tetra(fluothane polyethenoxy ether), fluothane ammonium iodide, fluothane lycine, Perfluoroalkyl polyethenoxy ether and perfluoroalkyl alkanol. In another example of the present invention, the fluorine-containing surfactant is BM-1000, BM-1100 (manufactured by BM CHEMIE), Megafac F142D, F172, F173, F183, F178, F191, F471, F476 (manufactured by Dainippon Ink And Chemicals, Inc.), Fluorad FC 170C, FC-171, FC-430, FC-431 (manufactured by Sumitomo Chemical Co., Ltd), chlorofluorocarbons S-112, S-113, S-131, S-141, S-145, S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (manufactured by AGC Display Glass Co., Ltd.), F Top EF301, 303, 352 (manufactured by Shin-Akita Kasei), Ftergent FT-100, FT-110, FT-140A, FT-150, FT-250, FT-251, FTX-251, FTX-218, FT-300, FT-310, FT-400S (manufactured by NEOSU). The specific examples of the aforementioned silicone surfactant are as below: Toray silicone, with the trade name of DC 3 Paint Additive (DC 3 PA), DC 7 PA, SH 11 PA, SH 21 PA, SH 28 PA, SH 29 PA, SH 30 PA, SH 190, SH 193, SZ 6032, SF-8427, SF-8428, DC 57, DC 190 (manufactured by Dow Corning Toray Silicone), TSF-4440, TSF-4300, TSF-4445, TSF-4446, TSF-4460, TSF-4452 (manufactured by Momentive Performance Materials Inc.). The aforementioned surfactant may also be other surfactants in addition to the aforementioned fluorine-containing surfactant and a silicone surfactant, and the other surfactants may include but be not limited to polyoxyethylene alkyl ether, such as lauryl alcohol polyoxyethylene ether, polyoxyethylene stearate ether and polyoxyethylene oleyl ether; polyoxyethylene aryl ether, such as polyoxyethylene n-octyl phenyl ether and polyoxyethylene n-nonyl ether; polyoxyethylene dialkyl, such as polyoxyethylene dilaurate and polyoxyethylene distearate; and nonionic surfactant, such as KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.) and poly flow No. 57, 95 (manufactured by Kyoeisha grease Chemical Industries, Ltd.). The aforementioned surfactant can be used separately or with a mixture of a plurality of the surfactants. The aforementioned adhesion accelerator can improve the adherence of the substrate, and the adhesion accelerator is preferably a functional silane crosslinking agent. Preferably, the functional silane crosslinking agent includes carboxyl group, thiazolinyl group, isocyanate group, epoxy group, amido group, hydrosulphonyl group or halogens. The specific examples of the aforementioned adhesion accelerator areas below: p-hydroxy phenyl trimethoxyl silane, 3-methacryloxypropyl trimethoxysilane, vinyl triacetoxysilane, vinyl trimethoxysilane, vinyl triethoxylsilane, vinyl tri(2-methoxyethoxyl)silane, γ-isocyanatepropyl triethoxylsilane, 3-ethoxylpropoxylpropyl trimethoxysilane, 2-(3,4-ethoxylcyclohexyl)ethyl trimethoxysilane, 3-ethoxylpropoxyl dimethyl methoxylsilane, 3-aminopropyl trimethoxysilane, N-(2-amidoethyl)-3-amidopropyl trimethoxysilane, N-(2-amidoethyl)-3-amidopropylmethyl dimethoxysilane, 3-mercaptpropyl trimethoxysilane, 3-chloropropyl trimethoxysilane and 3-chloropropylmethyl dimethoxysilane. The aforementioned adhesion accelerator can be used separately or with a mixture of a plurality of the adhesion accelerators according to the requirements. The aforementioned storage stabilizer may include but be not limited to sulfur, quinones, hydroquinones, polyoxides, amines, nitroso compounds or nitryl group, and the specific examples thereof are as below: 4-methoxyl phenol, (N-nitroso-N-phenyl)hydroxylamine aluminum, 2,2′-thio-bis(4-methyl-6-t-butylphenol) and 2,6-di-t-butylphenol. The aforementioned heat-resistance promoter may include be but not limited to N-(alkoxymethyl)glycoluril compound and N-(alkoxymethyl) melamine. The specific examples of the aforementioned N-(alkoxymethyl)glycoluril compound are as below: N,N,N′,N′-tetra(methoxylmethyl)glycoluril, N,N,N′,N′-tetra(ethoxylmethyl)glycoluril, N,N,N′,N′-tetra(n-propoxylmethyl)glycoluril, N,N,N′,N′-tetra(isopropoxylmethyl)glycoluril, N,N,N′,N′-tetra(n-butoxymethyl)glycoluril and N,N,N′,N′-tetra(t-butoxymethyl)glycoluril, and preferably the N,N,N′,N′-tetra(methoxylmethyl)glycoluril. The specific examples of the aforementioned N-(alkoxymethyl)melamine are as below: N,N,N′,N′,N″,N″-hexa(methoxylmethyl)melamine, N,N,N′,N′,N″,N″-hexa(ethoxylmethyl)melamine, N,N,N′,N′,N″,N″-hexa(n-propoxylmethyl)melamine, N,N,N′,N′,N″,N″-hexa(isopropoxylmethyl)melamine, N,N,N′,N′,N″,N″-hexa(n-butoxymethyl)melamine and N,N,N′,N′,N″,N″-hexa(t-butoxymethyl)melamine, and preferably the N,N,N′,N′,N″,N″-hexa(methoxylmethyl)melamine. The commercial products of the aforementioned N-(alkoxymethyl)melamine are exemplified as NIKARAKKU N-2702, MW-30M (manufactured by Sanwa Chemical). The amount of the additives (G) of the present invention can be determined by those skilled in the art. Preferably, based on the amount of the alkali-soluble resin (A) as 100 parts by weight, the amount of the additives (G) is 0 parts by weight to 10 parts by weight, preferably 0 parts by weight to 6 parts by weight, and more preferably 0 parts by weight to 3 parts by weight. Photosensitive Resin Composition The photosensitive resin composition of the present invention is generally manufactured by mixing the aforementioned alkali-soluble resin (A), compound (B) containing vinyl unsaturated group(s), photoinitiator (C), ortho-naphthoquinone diazide sulfonic acid ester (D), thermal initiator (E) and solvent (F) in a mixer uniformly to get a solution. If necessary, the photosensitive resin composition can be added with additives (G) such as a loading agent, polymers except the alkali-soluble resin (A), ultraviolet light absorber, anti-agglutinant, surfactant, adhesion accelerator, storage stabilizer or heat-resistance promoter. Preparation Method of Spacer or Protective Film The present invention provides a method for forming a thin film on the substrate, in which the photosensitive resin composition of the present invention is applied onto the substrate; and preferably, the thin film is a spacer or protective film. In an example of the present invention, the preparation method of the spacer or protective film at least includes the following steps: (a) applying the photosensitive resin composition of the present invention onto the substrate to form a thin film; (b) exposing at least one part of the thin film with radiation light; (c) developing after the exposure; and (d) heating after the development. Those steps are sequentially illustrated as follows: In the step (a), the photosensitive resin composition of the present invention is applied onto the substrate to form a thin film. During forming of the thin film, a pixel layer consisting of red, green and blue coloring layers is first formed on a transparent substrate, and then the photosensitive resin composition of the present invention is formed on the pixel layer. During the formation of the spacer, a transparent conductive film is formed on the transparent substrate where the protective film and pixel layer are already formed, and then a thin film of the photosensitive resin composition of the present invention is formed on the transparent conductive film. In an example of the present invention, the transparent substrate is a glass substrate or a resin substrate, and preferably is the glass substrate, such as soda-lime glass and alkali-free glass. The specific examples of the resin substrate are polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate and polyimide. An example of the transparent conductive film formed on the whole surface of the transparent substrate is a NESA film (USA PPG) that includes SnO 2 or an ITO film that includes In 2 O 3 —SnO 2 . The film forming method includes coating or dry film method. In the coating method, the photosensitive resin composition of the present invention is coated on the aforementioned transparent conductive film or the transparent substrate, and the being-coated surface of which is preferably heated (prebaking). The concentration of the solid contents in the composition solution applied in the coating method is 5 parts by weight to 50 parts by weight, preferably 10 parts by weight to 40 parts by weight, and more preferably 15 parts by weight to 35 parts by weight. The coating method may include but be not limited to spray coating, roll coating, spin coating, slit die coating, stick coating and inkjet coating, in which the spin coating or the slit die coating is preferred. Additionally, in the dry film method, a photosensitive dry film containing the photosensitive resin composition of the present invention (photosensitive dry film for short) is stacked on a base film. On a dry film, the aforementioned photosensitive dry film can be stacked and form a photosensitive film after the solvent is removed. The concentration of the solid contents in the composition solution applied for the dry film method is 5 parts by weight to 50 parts by weight, preferably 10 parts by weight to 50 parts by weight, more preferably 20 parts by weight to 50 parts by weight, and more preferably 30 parts by weight to 50 parts by weight. The specific examples of the photosensitive dry film are polyethylene terephthalate (PET), polyethylene, polypropylene, polycarbonate and polyvinyl chloride. The thickness of the base film of the photosensitive dry film is preferably 15 μm to 125 μm, and more preferably 1 μm to 30 μm. The photosensitive dry film can also be stacked and covered with a covering film for storage when being not used. The covering film of the present invention is preferably releasable, so that it can be easily separated for use and not be separated when not being used. The specific example of the covering film having the aforementioned characteristic is a synthetic resin film such as a PET thin film, a polypropylene thin film, a polyethylene thin film, a polyvinyl chloride thin film and a polyurethane thin film, which is coated or printed with a silicone release agent thereon. The thickness of the covering film is about 5 to 30 μm. The covering film can also be stacked of two or three layers. In a specific example of the dry film stacking method, a transparent base film can be hot-press laminated with a transparent photosensitive dry film. Among the aforementioned methods, the film is preferably prepared by the coating method prior to the dry film method, and more preferably performs a pre-baking step before the coating method. The pre-baking conditions can be different according to the composition and the mixing proportion, and preferably the film is heated at 70-120° C. for 1-15 minutes. Among the aforementioned methods, the film is preferably prepared by the coating method prior to the dry film method. The thickness of the film after pre-baking is preferably 0.5 to 10 μm, and more preferably 1.0 to 7.0 μm. In step (b) at least one part of the thin film is irradiated with radiation light. When a part of the film is irradiated, a light mask with a predetermined pattern, for example, can be used. The specific example of the radiation light is the visible light, the ultraviolet light or the far-infrared light. The wavelength of the radiation light is preferably 250 to 550 nm, which includes the range of the ultraviolet light, and more preferably 365 nm is included. Radiation amount (exposure amount) is the radiation light intensity measured through a luminometer (OAI model 356, Optical Associates Inc.) at a wavelength of 365 nm. The radiation light intensity is preferably 100 to 5,000 J/m 2 , and more preferably 200 to 3,000 J/m 2 . In step (c), the development is performed after the irradiation, so as to remove unnecessary parts and form a predetermined pattern. A specific example of the developing solution is inorganic base, such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, metasilicate sodium and ammonia; the primary fatty amine, such as ethylamine and n-propylamine; the secondary fatty amine, such as diethylamine and n-propylamine; the tertiary fatty amine, such as trimethylamine, diethylamine methyl, dimethylethylamine and triethylamine; the tertiary fatty cyclo-acid, such as pyrrole, piperidine, N-methyl piperidine, N-methyl 1,8-diazabicyclo[5.4.0]-7-undecylene and 1,5-diazabicyclo[4.3.0]-5-nonene; the third-grade aromatic amine, such as pyridine, methylpyrimidine, dimethyl pyridine and quinoline; and the quaternary ammonium salt alkaline compound, such as the aqueous solution of tetramethyl ammonium hydroxide and tetraethyl ammonium hydroxide. The water-soluble organic solvent and/or surfactant, such as methanol and ethanol, can also be added into the aforementioned alkaline compound according to requirements. The development method is exemplified as an immersion method, including a soaking method, an immersion method or a showering method, and preferably the development method is performed for about 10 seconds under room temperature to 180° C. The desired pattern is washed with vapor for 30 to 90 seconds after the development, and then is dried through the compressed air or nitrogen. In step (d) heating is performed after the development. The resulted film with pattern is heated for 30 to 180 minutes in an appropriate heater such as a heating plate or a baking oven (post baking). The aforementioned resulted spacer or protective film with the desired pattern has excellent characteristics such as anti-stress strength, abrasive resistance of the liquid crystal alignment film thereof and the adherence to the substrate. Preparation Method of Liquid Crystal Display Device The present invention also provides a LCD including the aforementioned thin film. In the LCD of the present invention the aforementioned photosensitive resin composition is used to form a spacer, and at least one side of the LCD a protective film is formed, and more preferably at both sides. The LCD of the present invention can be prepared though the following two methods. (1) On one side or both sides of a first (electrode) transparent substrate with a transparent conductive film on at least one side thereof, the photosensitive resin composition of the present invention is formed as a protective film or spacer through the aforementioned methods. Thereafter, an alignment film has characteristic of liquid crystal alignment is formed on the transparent conductive layer having the spacer and/or protective film. The sides of these substrates where the alignment films are formed are regarded as the inner face, and the liquid crystal directions of various alignment films are antiparallel or perpendicular to each other and the alignment films are reverse configured with certain intercellular spaces. The intercellular space defined by the substrate surface (alignment film) and the gap is filled with liquid crystal, and then the filled holes are encapsulated as liquid crystal units. Therefore the internal and external liquid crystal units can form a LCD with the same alignment direction on both internal and external surfaces by adhering to a vertical polarizer or being arranged at a liquid crystal polarization direction of a substrate surface. (2) On one side or both sides of a first transparent substrate with a transparent conductive film on at least one side thereof, the photosensitive resin composition of the present invention is formed as a protective film or spacer through the methods aforementioned in (1). Afterwards, a UV curing type adhesion agent is coated on the substrate along the end points, and afterwards tiny liquid crystal is dropped onto the substrate through a liquid crystal dispenser, and then the substrate is stacked under vacuum, and the substrate can be encapsulated under a high-pressure mercury lamp that can emit ultraviolet light. Finally the polarizing plates inside and outside the liquid crystal are adhered to form the liquid crystal display device. The specific example of the LCD of the present embodiment is applied in a nematic liquid crystal or a smectic liquid crystal, and preferably is the nematic liquid crystal, such as the Shiff basic type liquid crystal, azoxy liquid crystal, diphenyl liquid crystal, phenylcyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, dioxanepoly cyclooctane liquid crystal, bicyclicoctane liquid crystal, cuneone liquid crystal, chloride liquid crystal, cholesteric liquid crystal such as the cholesterol carbonate or cholesteric liquid crystal; and ferroelectric liquid crystal including chiral materials such as p-decyloxy benzylidene-p-amido-2-methylbutyl cinnamate (C-15, CB-15, manufactured by Merck) may also be added. At the external side of the liquid crystal a polarizing plate, alignment extending of the polyvinyl alcohol, a ┌H film┘ which can absorb iodine or a H film clamped between a fiber acetate protective film and the polarizing plate is used. Various embodiments are used hereinafter to illustrate the application of the present invention, but it is not intended to limit the present invention. For those skilled in the art of the present invention, various variations and modifications can be made without departing from the spirit and scope of the present invention. DETAILED DESCRIPTION The following are Synthesis Examples 1 to 3 for synthesizing the alkali-soluble resins (A-1) to (A-3) according to Table 1. Synthesis Example 1 Method of Synthesizing Alkali-Soluble Resin (A-1) A 1000 mL four-necked conical flask equipped with a nitrogen inlet, a stirrer, a heater, a condenser and a thermometer was purged with nitrogen gas, and the components listed in Table 1 were charged to the flask. The aforementioned components comprising 30 parts by weight of methacrylic acid (hereinafter abbreviated as MAA), 25 parts by weight of t-butyl methacylate (hereinafter abbreviated as TBMA), 20 parts by weight of styrene monomer (hereinafter abbreviated as SM), 2.4 parts by weight of 2,2′-azobis(2-methyl butyronitrile) (hereinafter abbreviated as AMBN) and 240 parts by weight of diethylene glycol dimethyl ether (hereinafter abbreviated as Diglyme) were stirred slowly, heated to 85° C. and left to polycondense for 5 hours at the same temperature. Subsequently, after the solvent was volatilized, the alkali-soluble resin (A-1) was obtained. Synthesis Example 2 Method of Synthesizing Alkali-Soluble Resin (A-2) A 1000 mL four-necked conical flask equipped with a nitrogen inlet, a stirrer, a heater, a condenser and a thermometer was purged with nitrogen gas, and the components listed in Table 1 were charged to the flask. The aforementioned components comprising 35 parts by weight of 2-methacryloyloxyethyl succinate monoester (hereinafter abbreviated as HOMS), 20 parts by weight of 3,4-epoxycyclohexylmethyl methacrylate (hereinafter abbreviated as EC-MAA), 5 parts by weight of 2-hydroxyethyl methacrylate (hereinafter abbreviated as HEMA), 20 parts by weight of dicyclopentanyl methacrylate (hereinafter abbreviated as FA-513M), 20 parts by weight of SM, 2.4 parts by weight of 2,2′-azobis(2,4-dimethylvaleronitrile (hereinafter abbreviated as ADVN) and 240 parts by weight of propylene glycol monomethyl ether acetate (hereinafter abbreviated as PGMEA) were stirred slowly, heated to 80° C. and left to polycondense for 6 hours at the same temperature. Subsequently, after the solvent was volatilized, the alkali-soluble resin (A-2) was obtained. Synthesis Example 3 Method of Synthesizing Alkali-Soluble Resin (A-3) A 1000 mL four-necked conical flask equipped with a nitrogen inlet, a stirrer, a heater, a condenser and a thermometer was purged with nitrogen gas, and the components listed in Table 1 were charged to the flask. The aforementioned components comprising 30 parts by weight of MAA, 20 parts by weight of GMA, 5 parts by weight of EC-MAA, 10 parts by weight of HEMA, 10 parts by weight of FA-513M, 25 parts by weight of benzyl methacrylate (hereinafter abbreviated as BzMA), 3.0 parts by weight of AMBN, 200 parts by weight of Diglyme and 40 parts by weight of PGMEA were stirred slowly, heated to 85° C. and left to polycondense for 5 hours at the same temperature. Subsequently, after the solvent was volatilized, the alkali-soluble resin (A-3) was obtained. Method of Preparing Photosensitive Resin Composition The following are Examples 1 to 7 and Comparative Examples 1 to 3 for preparing the photosensitive resin compositions according to Table 2. Example 1 100 parts by weight of alkali-soluble resin (A-1), 20 parts by weight of dipentaerythritol hexaacrylate (B-1), 10 parts by weight of 1-[4-(phenylthio)phenyl]-octane-1,2-diketone 2-(O-benzoyloxime) (C-1), 0.2 parts by weight of ortho-naphthoquinone diazide sulfonic acid ester (D-1) formed from the 4,4′-[1-[4-[−1-(4-hydroxy phenyl)-1-methylethyl]phenyl]ethylene]bisphenol and ortho-naphthoquinone diazide-5-sulfonic acid, and 1 parts by weight of cumyl peroxyneodecanoate (E-2) were mixed and dissolved in 500 parts by weight of propylene glycol monomethyl ether acetate (F-1) completely, so as to form the photosensitive resin composition of Example 1. Afterwards, the sensibility of the spacer formed by the photosensitive resin composition and the shape of the post-baked pattern were measured by using the detection methods of the resolution and the development adherence that were described as follows. Examples 2 to 7 Examples 2 to 7 were practiced with the same method as in Example 1 by using various kinds or amounts of the components of the photosensitive resin composition, the formulas and evaluation results of which were listed in Table 2. Comparative Examples 1 to 3 Comparative Examples 1 to 3 were practiced with the same method as in Example 1 by using various kinds or amounts of the components of the photosensitive resin composition, the formulas and evaluation results of which were also listed in Table 2. Method of Preparing Spacer or Protective Film Various photosensitive resin compositions of Examples 1 to 7 and comparative examples 1 to 3 were spin coated independently on a prime glass substrate of 100×100×0.7 mm in size, and then pre-baked for 2-3 minutes at 90° C. to obtain a pre-baked coating film of about 6 μm in thickness. And then, the pre-baked coating film was placed under the light mask with a given pattern, and ultraviolet light (exposure machine AG500-4N; manufactured by M&R Nano Technology) of 100 mJ/cm 2 was used to irradiate the film. Afterwards, the exposed coating film was immersed in 0.05% KOH solution for 45 seconds to remove the unexposed parts, and then the film was washed by pure water; followed by being post-baked for 30 minutes at 235° C., so as to form a spacer or protective film that includes columns with the given pattern formed through the light mask on the prime glass substrate. Performance Evaluation of the Spacer Film or Protective Film The resolution and development adherence of the aforementioned resulted spacer film or protective film could be detected in the following steps, so as to evaluate the performance thereof. 1. Resolution: The spacer film or protective film formed on the prime glass substrate was observed under a microscope (for example, Eclipse 50i, manufactured by Nikon) and a scanning electron microscope (SEM) (for example S-3000N, manufactured by Hitachi) to detect the minimum possible diameter of the column that can be formed. ◯: minimum possible diameter of the column≦15 μm Δ: 15≦μm minimum possible diameter of the column<20 μm X: 20 μm<minimum possible diameter of the column 2. Development Adherence: The pre-baked coating film was placed under the light mask with a given pattern, and ultraviolet light (exposure machine AG500-4N; manufactured by M&R Nano Technology) of 100 mJ/cm 2 was used to perform the exposure step. Afterwards, the exposed coating film was immersed in 0.05% KOH solution for 45 seconds to remove the unexposed parts, and then 100 columns with a diameter of 15 μm were developed. After being washed with pure water, the number of the developable columns was detected with a microscope (for example, Eclipse 50i, manufactured by Nikon). ◯: less than 10 damaged columns X: equal to or more than 10 damaged columns According to the results of Table 2, when the ortho-naphthoquinone diazide sulfonic acid ester (D) and the thermal initiator (E) are added into the photosensitive resin composition, the resulted spacer film or protective film will have an excellent resolution and development adherence for achieving the purpose of the present invention. It should be supplemented that, although specific compounds, components, reactive conditions, processes, analysis methods or specific equipment are described as examples of the present invention, to illustrate the light guide plate, light-emitting unit and the LCD having the light-emitting unit of the present invention. However, as is understood by a person skilled in the art, the present invention is not limited to those. Without departing from the spirit and scope of the present invention, the light guide plate, light-emitting unit and the LCD having the light-emitting unit of the present invention also can be manufactured by using other compounds, components, reactive conditions, processes, analysis methods and equipment. As is understood by a person skilled in the art, the foregoing preferred embodiments of the present invention are illustrated of the present invention rather than limiting of the present invention. In view of the foregoing, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims. Therefore, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structure. TABLE 1 Components Synthesis Polymerizable Monomers (parts by weight) Examples MAA HOMS GMA EC-MAA HEMA TBMA FA-513M BzMA SM A-1 30 25 25 20 A-2 35 20 5 20 20 A-3 30 20 5 10 10 25 Components Solvent Catalyst Reaction Polycondensation Synthesis (parts by weight) (parts by weight) temperature time Examples Diglyme PGMEA AMBN ADVN (° C.) (h) A-1 240 2.4 85 5 A-2 240 2.4 80 6 A-3 200 40 3.0 85 5 Compounds Names AMBN 2,2′-azobis(2-methyl butyronitrile) ADVN 2,2′-azobis(2,4-dimethylvaleronitrile) MAA methacrylic acid HOMS 2-methacryloyloxyethyl succinate monoester GMA glycidyl methacylate EC-MAA 3,4-epoxycyclohexylmethyl methacrylate HEMA 2-hydroxyethyl methacrylate TBMA t-butyl methacrylate FA-513M dicyclopentanyl methacrylate BzMA benzyl methacrylate SM styrene monomer Diglyme diethylene glycol dimethyl ether PGMEA propylene glycol monoethyl ether acetate TABLE 2 Comparative Examples Examples Components 1 2 3 4 5 6 7 1 2 3 Alkali-soluble resin (A) A-1 100 50 100 100 (parts by weight) A-2 100 50 100 100 A-3 100 100 100 Compound (B) containing vinyl B-1 20 30 100 80 100 100 unsaturated group(s) B-2 100 150 100 100 (parts by weight) B-3 20 100 Photoinitiator (C) C-1 10 15 30 30 15 30 30 (parts by weight) C-2 20 30 20 C-3 5 5 10 10 5 Ortho-naphthoquinone diazide D-1 0.2 15 4 5 sulfonic acid ester (D) D-2 5 5 6 (parts by weight) D-3 10 5 Thermal initiator (E) E-1 3 3 1 3 (parts by weight) E-2 1 3 10 0.2 E-3 8 2 Solvent (F) F-1 500 1500 1000 2000 1000 500 3000 1500 1000 1000 (parts by weight) F-2 500 500 500 Additive (G) Surfactant G-1 0.1 (parts by weight) Development G-2 0.3 Adherence Evaluation items Resolution ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ X X Development ◯ ◯ ◯ ◯ ◯ ◯ ◯ X ◯ X Adherence (the amounts of the components each is based on the alkali-soluble resin (A) of 100 parts by weight) Compounds Names B-1 dipentaerythritol hexaacrylate B-2 dipentaerythritol tetraacrylate B-3 PO modified glycerol triacrylate C-1 phenylthiooctanediketonebenzoylbenzoyloxime[1-[4-(phenylthio)phenyl]-octane-1,2-dione 2-(O-benzoyloxime)] C-2 2-methyl-1-[4-(methylthio) phenyl]-2-morpholino-1-propanone (manufactured by Ciba Specialty Chemicals) C-3 4,4′-bis(diethylamino) benzophenone (manufactured by Ciba Specialty Chemicals) D-1 ortho-naphthoquinone diazide sulfonic acid ester formed from 4,4′-[1-[4[-1-(4-hydroxy phenyl)-1- methylethyl]phenyl]ethylene]bisphenol and ortho-naphthoquinone diazide-5-sulfonic acid D-2 ortho-naphthoquinone diazide sulfonic acid ester formed from 2,3,4-trihydroxybenzophenone and ortho- naphthoquinone diazide-5-sulfonic acid D-3 ortho-naphthoquinone diazide sulfonic acid ester formed from 2-(2,3,4-trihydroxyphenyl)-2-(2′,3′,4′- trihydroxyphenyl) propane and ortho-naphthoquinone diazide-5-sulfonic acid E-1 2,2′-azobis(2,4-dimethylvaleromtnle) E-2 cumyl peroxyneodecanoate E-3 p-menthane hydroperoxide F-1 propylene glycol monomethyl ether acetate F-2 diethylene glycol dimethyl ether G-1 SF-8427 G-2 methoxyl 3-methacryloxypropyl trimethoxysilane

The present invention relates to a photosensitive resin composition, which comprises an alkali-soluble resin (A), a compound (B) containing vinyl unsaturated group(s), a photoinitiator (C), ortho-naphthoquinone diazide sulfonic acid ester (D), a thermal initiator (E) and a solvent (F). The photosensitive resin composition added with the ortho-naphthoquinone diazide sulfonic acid ester (D) and the thermal initiator (E) can have excellent resolution and development adherence. Moreover, the present invention further provides a spacer or a protective film formed by the aforementioned photosensitive resin composition, as well as a liquid crystal display device (LCD) including the aforementioned spacer or protective film.

TECHNICAL FIELD [0001] The subject matter described herein relates generally to the test and measurement of wireless data communication systems; and more particularly to systems and methods for analyzing waveforms generated by multiple-input multiple-output data communication systems, including but not limited to multi-user multiple-input multiple-output data communication systems. BACKGROUND [0002] Wireless data communications devices, systems and networks that are in widespread use worldwide have become sophisticated and complex, due to the increasing need for higher data rates and the support of an increased number of users and data traffic. Accomplishing these higher rates and traffic capacities usually requires employing complex signal waveforms and advanced radio frequency capabilities such as multiple-input multiple-output (MIMO) signal coding, transmit and receive signal management methods such as beamforming, and spatial multiplexing techniques. MIMO coding in particular has received significant recent interest, as it employs the statistical properties of RF propagation channels to achieve higher data rates as well as to simultaneously accommodate multiple users (spatial multiplexing). All of these techniques, however, increase the complexity of the wireless devices. Manufacturers, vendors and users therefore have a greater need for better testing of such systems. [0003] Unfortunately, the increasing complexity of wireless data communication devices and systems also makes them harder to test. Testing MIMO wireless systems is particularly problematic due to the difficulty of re-creating the dynamic RF channel environment. Actual open-air RF environments contain high levels of uncontrollable noise and interference, and also present time-varying and unpredictable channel statistics. However, the performance of MIMO systems is very dependent on the channel statistics. The lack of controllability and repeatability also makes it difficult or impossible to automate the testing of such wireless systems. Therefore it is very attractive to manufacturers and users to test these devices in a repeatable fashion by excluding the variability of real MIMO RF channels while still interposing accurately simulated but controllable channels. This also enables the tests to be conducted in an automated fashion. [0004] With reference to FIG. 1 , an exemplary MIMO wireless transmitter 101 and an exemplary MIMO wireless receiver 102 is shown in a simplified RF propagation environment, that may consist of an arbitrary number of RF scatterers 107 . MIMO transmitter 101 has a plurality of antennas 103 . Similarly, MIMO receiver 102 has a plurality of antennas 104 . As depicted in FIG. 1 , the multiplicity of antennas enable the transmission of multiple parallel streams of information 106 , utilizing the available transmission paths (or ‘modes’) in the RF environment, which are created by the presence of scatterers 107 . It is apparent that the performance gains due to MIMO occur as a consequence of these multiple transmission modes; removal of the scatterers causes the multiple transmission modes to collapse into a single mode, and the channel will then become unable to support more than one stream of information. Therefore, any MIMO test system must provide a means of supporting multiple transmission modes in the path between the transmitter and the receiver. [0005] FIG. 2 is illustrative of a simplified MIMO wireless traffic and radio analyzer 111 that may be coupled to a wireless device under test (DUT) 110 containing MIMO radio interface 112 by RF cables 113 . In this case, the multiple transmission modes of the real RF propagation channel may be simulated by the multiple separate cables 113 , which may interconnect RF transmitters and receivers in pairs. The number of independent transmission modes (and therefore the number of parallel data streams) is equal to the number of distinct RF cables and associated transmitter/receiver pairs. All external interference, noise and propagation variations are excluded by virtue of the use of such a fully cabled RF setup. [0006] For representational purposes, FIG. 2 and all succeeding figures herein show three cables, antennas, transmission paths, modes, etc. However, it should be understood that this is done for representational convenience, and the actual number thereof may be any number including 1. It is also not necessary for the numbers of transmitters, receivers, cables, antennas, transmission paths, modes, etc. to be equal to each other. The discussion and teachings herein are equally applicable to a MIMO system comprising any number of transmission paths and antennas and any other number of reception paths and antennas. [0007] The exemplary system depicted in FIG. 2 shows an idealized (nearly lossless, noiseless and distortion-free) MIMO RF channel between analyzer 111 and DUT 110 . In practice, however, RF propagation channels are neither lossless nor distortion-free. Turning now to FIG. 3 , the loss and amplitude/phase distortion presented by actual RF propagation channels may be simulated by channel simulator (fader) 120 , which is interposed between analyzer 111 and DUT 110 . Such a channel simulator 120 is connected to analyzer 111 by RF cables 113 , and to DUT 110 by RF cables 121 , and therefore the system continues to exclude external interference and avoid uncontrollable propagation variations. However, the propagation characteristics of actual RF channels can be simulated in a controlled and repeatable fashion by modifying the configuration of channel simulator 120 . The design of such a channel simulator 120 is well known in the art and will not be repeated here. [0008] FIG. 4 depicts a situation where a single MIMO receiver 130 may receive signals concurrently from a plurality of MIMO transmitters 131 , 132 , 133 . With a sufficiently large number of scatterers 135 in the RF propagation environment, it is possible for completely independent transmission paths (i.e., propagation modes) to be present between each of the MIMO transmitters 131 , 132 , 133 with respect to MIMO receiver 130 . By applying appropriate digital signal processing (DSP) functions, it is possible for MIMO receiver 130 to distinguish and separate the transmitted signals from each other by virtue of these independent propagation modes. It may therefore be possible for multiple users to concurrently transmit RF signals within the same frequency band to the same receiver. This is a form of spatial multiplexing referred to as multi-user MIMO (MU-MIMO). It should be noted that the statistical properties of the RF propagation channels between the transmitters and the receiver are even more important for MU-MIMO, as the parallel streams of information are disambiguated and extracted solely by virtue of their having traversed different RF paths and having been subjected to different amplitude/phase distortions. [0009] It will be appreciated that the situation in FIG. 4 may equally apply to a single MIMO transmitter concurrently transmitting data streams to a plurality of MIMO receivers. In this case, the transmitter may accept parallel streams of information destined for separate receivers, apply different signal processing functions to the data streams, and combine these streams for transmission on a single set of antennas. The signal processing functions are selected in such a way as to employ the statistical properties of the different RF channels existing between the transmitter and the various receivers, and maximize the desired signal at each receiver while minimizing the undesired signals (i.e., those destined for other receivers). [0010] To enable distinct RF propagation channels to concurrently support separate MU-MIMO data streams, it may be essential that the characteristics of each individual RF propagation channel be accurately determined. This is normally performed by a process referred to as sounding the channel. Sounding entails transmitting a known signal with precisely defined properties from each transmitter to each associated receiver, and then measuring the received signal at the receiver. The RF channel between the transmitter and the receiver can then be estimated by comparing the received signal with the predetermined transmitted signal. The receiver may then feed the measured RF channel properties back to the transmitter using a predetermined control protocol. The transmitter uses these channel properties to adapt subsequently transmitted signals to the RF channel between itself and the receiver, thereby ensuring that the reception probability is maximized at the target receiver and minimized everywhere else. [0011] With reference to FIG. 5 , a possible arrangement for testing a MU-MIMO DUT 147 containing MU-MIMO radio interface 148 is depicted. In this case, wireless radio and traffic analyzers 141 , 142 , 143 may simulate a plurality of spatially distributed end-stations, generating independent streams of wireless traffic to DUT 147 . As MU-MIMO relies upon the existence of different RF propagation channels between transmitter/receiver pairs, separate channel simulators 144 , 145 , 146 may be employed, one for each of analyzers 141 , 142 , 143 . Each channel simulator may be configured to simulate a different radio channel. The outputs of channel simulators 144 , 145 , 146 may be combined together via RF power combiners 149 and fed to MIMO radio interface 148 in DUT 147 . [0012] Such an arrangement, unfortunately, suffers from several significant shortcomings. Firstly, the use of separate channel simulators 144 , 145 , 146 causes such a system to become prohibitively expensive. This is particularly true as the number of end stations represented by analyzers 141 , 142 , 143 increases to a large number (e.g., 500). Secondly, coupling together multiple channel simulators 144 , 145 , 146 causes them to interact in unpredictable ways, considerably degrading the effectiveness of the simulated RF channels, and often causing substantial distortion effects. Finally, such a system presents significant issues in terms of signal dynamic range, particularly as the number of channel simulators increases; a high-amplitude signal produced by one channel simulator may overload another channel simulator which may be producing a low amplitude signal. For these reasons, simply attaching together multiple channel simulators 144 , 145 , 146 to create an MU-MIMO test system is not feasible except for certain limited and carefully selected cases. [0013] To comprehend the general functioning of an MU-MIMO system, the operation of a simple MIMO system (i.e., a single MIMO transmitter and a single MIMO receiver) will be considered first. With reference to FIG. 6 , an exemplary MIMO transmitter 150 that may incorporate one method of beamforming is depicted, using one or more antennas 157 to transmit RF signals over some RF propagation medium to one or more antennas 161 of an exemplary MIMO receiver 160 . [0014] MIMO transmitter 150 may include: transmit digital data input 151 , digital modulator 152 that may transform digital data to the modulation domain, for example by employing Orthogonal Frequency Division Multiplexing (OFDM); space-time mapper 153 that may map modulated symbols to one or more output streams of symbols according to some MIMO mapping algorithm; transmit precoder 154 that may perform some transformation upon the symbol streams to adapt them for transmission; digital to analog (D/A) converters 155 that may convert the digital representation of the transformed symbols to analog; and transmit RF processing functions 156 that may convert these analog signals to some desired radio frequency and transmit them using one or more antennas 157 . It is understood that other functions and processing elements may also be included in MIMO transmitter 150 , but are not relevant to this discussion and are therefore omitted. [0015] MIMO receiver 160 may receive transmitted RF signals from one or more antennas 161 , and may include: receive RF processing functions 162 that convert one or more streams of RF signals, after which analog to digital (A/D) conversion by A/D converters 163 may be performed to produce digital symbols; receive decoder 164 that may transform the streams of digital symbols prior to demapping and demodulation; and space-time demapper and digital demodulator 165 that may map and integrate one or more streams of symbols according to a predetermined space-time transformation, and may demodulate these symbols to recover received digital data 166 . Channel estimator 167 may calculate the properties of the RF propagation medium that may exist between transmit antennas 157 and receive antennas 161 , and supply this information to receive decoder 164 and space-time demapper and digital demodulator 165 , to aid in transforming and recovering the digital data 166 . It is likewise understood that other functions and processing elements may be included in MIMO receiver 160 but are omitted as they are not relevant to this discussion. [0016] The properties of the RF propagation medium influence the efficiency with which MIMO signals can be transmitted and received. The RF channel properties may be used to derive the coefficients that may be set into transmit precoder 154 to adapt the symbol streams generated by space-time mapper 153 to the propagation modes of the RF channel, which may maximize the information density of the channel. Such an adaptation may be commonly referred to as beamforming or, more specifically, eigen beamforming. The RF channel properties may further be used to calculate coefficients that may be set into receive decoder 164 to post-process the received symbol streams from the propagation modes of the RF channel, which may thereby enhance the signal-to-noise ratio at MIMO receiver 160 (indirectly further maximizing the information density of the channel). Such an enhancement may be commonly referred to as combining diversity. [0017] It is therefore apparent that an accurate knowledge of the properties of the RF channel, in particular its propagation modes, may be of great importance. It is also apparent that the receiver and transmitter may preferably share the properties of the RF channel, so that the processing performed at the transmitter corresponds to the processing performed at the receiver. Therefore, MIMO receiver 160 may preferably share channel information with MIMO transmitter 150 to achieve this goal, further preferably using a known and well defined protocol. Such a protocol for determining and sharing channel state information is commonly known as a beamforming information exchange process. [0018] Turning now to FIG. 7 , an exemplary procedure is depicted that may be used for determining the properties of the RF channel, for communicating these properties between the two ends of an RF link, and for utilizing these properties in the transmission and reception of data. Vertical lines 170 and 172 represent the operations of a MIMO transmitter and a MIMO receiver respectively. At 172 , the MIMO transmitter may generate some fixed test data having a prearranged bit pattern and predetermined modulation and spatial mapping characteristics, and may transmit this data as a sounding signal, for example within a sounding packet, as represented at 173 . At 174 , the MIMO receiver may receive and analyze the sounding signal, which may be a sounding packet. The original sounding signal waveform being known, at 175 the MIMO receiver may calculate the RF channel properties by their effect upon the sounding signal waveform, and may further compute a precoding matrix (that may, for instance, be used within exemplary MIMO transmitter 150 ) that maximizes the information density for the RF channel existing between the MIMO transmitter and receiver at that point in time and space. At 176 , the coefficients of the precoding matrix may be formatted into suitable packet(s) and transmitted at 177 as a beamforming information frame, completing the beamforming information exchange process. This beamforming information exchange process may sometimes also be referred to as a beamforming training sequence. [0019] At 178 , the MIMO transmitter may extract the coefficients of the precoding matrix that have been provided by the receiver and process them to obtain the actual configuration of the precoder, which may then be applied to the transmit precoder at 179 . Once the transmit precoder has been configured, the transmitter may subsequently send user data frames; these frames may be processed by the transmit precoder to adapt them to the RF channel and transmitted as precoded signals 180 . Such a process may maximize the signal to noise and interference ratio (SINR) at the MIMO receiver and may further enable optimal reception of the user data frames. (It is understood that the MIMO receiver may also utilize the RF channel properties to configure a receive decoder and receive demodulator, as is depicted in FIG. 6 and may yet further improve the SINR.) [0020] FIG. 8 shows a simplified exemplary mathematical model of the process of precoding, transmission through a MIMO RF channel, and decoding. With respect to FIG. 8 , vectors [x] and [y] represent complex-valued transmitted and received information signals respectively; complex vectors [V] and [U] may represent transmit precoding matrix and receive decoder matrix coefficients, respectively; and the RF channel existing between the MIMO transmitter and MIMO receiver is represented by [H]. At 200 , the user data stream is input as a sequence of vectors [x]. In transmit precoder 201 , the vectors are multiplied by the transmit precoding matrix [V], after which they are transmitted upon RF channel 202 . The effect of the RF channel 202 upon the transmitted signal is represented by a multiplication by the channel matrix [H]. These signals are received by receive decoder 203 and multiplied further by receive decoder matrix [U], yielding a sequence of vectors [y] that comprise the received data. Note that this depiction is highly simplified for the purposes of explanation and does not include such elements as modulation, demodulation, spatial mapping, spatial demapping, coding, etc. that are not germane to this discussion. Also note that this is a simplified model and does not take into account operations such as vector transposes that may actually be required for the vectors [U] and [V]. [0021] The beamforming information exchange process may attempt to determine the coefficients of vectors [V] and [U] that will maximize the SINR of the signal transmitted through channel matrix [H]. An optimal beamforming information exchange process may calculate these vectors in such a way that, barring the effects of noise, the signal [y] matches the signal [x]; i.e., the effect of RF channel matrix [H] is nullified. [0022] With regards to FIG. 9 , an exemplary mathematical model of an MU-MIMO process is depicted. Note that the model may be applied to any number of transmitters and any number of receivers. It may be observed that the steps are substantially similar to that of the basic MIMO process shown in FIG. 8 . Input signal vectors 210 , 215 , 220 corresponding to vectors [x 1 ], [x 2 ], [x 3 ] respectively may be precoded by transmit precoders 211 , 216 , 221 with transmit precoding matrices [V 1 ], [V 2 ], [V 3 ], after which they may transmitted over RF channels 212 , 217 , 222 with different channel matrices [H 1 ], [H 2 ], [H 3 ] respectively. A distinguishing feature of MU-MIMO is that all of the signals are transmitted concurrently and share the same spatial environment; therefore, at 225 the transmitted signals are shown as being arithmetically combined, so that the same signals are effectively received at all sets of receive antennas. These signals may then be processed by receive decoders 213 , 218 , 223 with receive decoder matrices [U 1 ], [U 2 ], [U 3 ] respectively, which may yield at 214 , 219 , 224 the output signal vectors [y 1 ], [y 2 ], [y 3 ]. Each transmit precoding matrix and each receive decoder matrix may preferably be adapted to the specific RF channel matrix existing between that transmitter/receiver pair. For instance, transmit precoding matrix [V 1 ] and receive decoder matrix [U 1 ] may be adapted to RF channel matrix [H 1 ], which may ensure optimal decoding of signal [y 1 ], and may further enable the RF signals generated by the other transmitter chains to be rejected. Separate channel estimation and beamforming feedback processes may hence be employed for each transmitter/receiver pair. As depicted in FIG. 10 , channel estimation function 230 may process the signal received as [y 1 ], and beamforming feedback function 234 may then pass the coefficients that may be used by transmit precoder 211 to the corresponding transmitter. Similarly, channel estimation functions 231 , 232 and beamforming feedback functions 235 , 236 may perform similar actions for other signal chains. [0023] It is known that if orthogonal channel matrices [H 1 ], [H 2 ], [H 3 ] exist between different transmitter/receiver pairs [V 1 ]/[U 1 ], [V 2 ]/[U 2 ], [V 3 ]/[U 3 ] respectively, then orthogonal transmission modes exist between each transmitter/receiver pair. The transmit precoding matrices may be adjusted to utilize these orthogonal transmission modes. Further, the receive decoder matrices may be adapted to perform diversity reception within these orthogonal transmission modes. This may have the effect of raising the SINR of the desired signals while reducing the SINR of the undesired signals. It is further known that such an arrangement may enable simultaneous transmission and reception of independent signals [x 1 ], [x 2 ], [x 3 ] over the same RF channel, which is the essence of MU-MIMO. [0024] It is understood that the transmitter chains shown in FIG. 10 may be combined into a single device, while the receiver chains may be present in separate devices. Alternatively, the transmitter chains may be in separate devices, while the receiver chain may be combined into one device. (This latter situation is represented in FIG. 4 .) Normal MU-MIMO usage situations entail one or the other of these cases. It is not of significant interest to consider the case of fully independent transmitter chains and fully independent receiver chains, as these degenerate to the standard MIMO usage situation. [0025] It is apparent that an MU-MIMO system requires an RF channel with a multiplicity of orthogonal transmission modes between the different transmitter/receiver pairs, so that the transmit precoders and receive decoders can be adjusted to enhance the desired signals while suppressing undesired signals and noise. However, this situation is not obtained in a fully cabled environment. With reference to FIG. 11 , a single MIMO transmitter/receiver pair is depicted, which may be equivalent to the MIMO transmitter/receiver pair shown in FIG. 8 with the exception that the antennas and the open-air MIMO RF transmission channel have been replaced by RF cables 241 . As these cables may be nearly lossless and free of reflections, they may represent a channel matrix [H c ] as shown at 240 , which is an identity matrix. This may still be a valid MIMO environment for a single transmitter/receiver pair, and may still enable transmit signal [x] at 200 to be transmitted through the system and received as signal [y] at 204 . Therefore, a MIMO system may still continue to function properly when cable-connected instead of using propagation through an actual RF environment. [0026] Turning now to FIG. 12 , a possible mathematical model of the MU-MIMO situation in a cabled environment is shown. This may comprise one or more transmitted signal streams 210 , 215 , 220 that may be precoded by transmit precoders 252 , 253 , 254 which implement the [V 1 ], [V 2 ], [V 3 ] transmit precoding matrices respectively. The signals may then be passed through unitary RF channels 240 , 241 , 242 , all of which have the identical RF transmission channel matrix [H c ] created by cables 243 . They may then be subsequently combined and distributed to receive decoders 213 , 218 , 223 as before, which may implement the [U 1 ], [U 2 ], [U 3 ] matrices respectively. The output signals [y 1 ], [y 2 ], [y 3 ] ( 214 , 219 , 224 respectively) may contain the decoded received data, which may also be fed to channel estimation functions 230 , 231 , 232 , the outputs of which in turn may be fed to beamforming feedback 234 , 235 , 236 and subsequently used to configure transmit precoders 252 , 253 , 254 . [0027] It will be observed that in a cabled environment RF channel matrices [H c ] between every pair of transmitter/receiver chains are identical, and are equal to the identity matrix. Further, channel estimation functions 230 , 231 , 232 will produce identical channel estimates, and hence the coefficients configured into transmit precoders 211 , 216 , 221 will be the same, as will the coefficients for receive decoders 213 , 218 , 223 . As MU-MIMO relies for its operation on orthogonal RF channels creating orthogonal transmission modes, it is readily apparent that such a system cannot support simultaneous transmission and reception of independent signals. In the cabled situation depicted, therefore, the capacity of the RF transmission channel collapses to that of the simple MIMO case, and testing of MU-MIMO operation is not possible. [0028] The known methods of MU-MIMO wireless testing therefore suffers from serious shortcomings. There is hence a need for improved MU-MIMO wireless data communication test systems and methods. A test system that is capable of performing tests upon MU-MIMO systems in a cabled environment may be desirable. It may be preferable for such a test system to eliminate the need for external channel simulators to enable the testing of multiple simultaneous transmitters or receivers at reduced cost. Further, such a test system may preferably permit different RF channels to be simulated for different transmitters or receivers without interaction between the channels. Finally, it may also be desirable for the test system to facilitate the testing of large-scale MU-MIMO systems with many transmitters and receivers. SUMMARY [0029] Systems and methods are disclosed herein that may provide improved techniques for performing testing of MIMO and MU-MIMO wireless data communication devices, systems and networks. Such techniques may enable the testing of such devices with reduced cost and higher efficiency, and may also decrease the complexity of the test system required to perform MIMO and MU-MIMO beamforming tests. The systems and methods disclosed may further extend the range and nature of the tests that may be performed, and may also allow automated tests to be conducted in a controlled and repeatable manner. [0030] In accordance with an aspect of one embodiment, a network equipment test device, such as a wireless signal analyzer, is disclosed that may be operative to perform tests upon MIMO and MU-MIMO transmitters in a controlled RF environment. The analyzer may contain: radio channel generation functions, which create a statistical model of a simulated RF channel; sounding packet handshake logic to exchange sounding signals with the DUT containing suitable channel coefficients; precoding matrix calculation functions, which convert the simulated RF channel properties into the precoder coefficients of the sounding signal sent to the DUT; and receive decoder matrix functions, which perform a matrix decode upon the signals received from the DUT. The system may be further operative to cause the DUT to transmit signals to be analyzed that are precoded with the desired RF channel properties. A network equipment test device according to embodiments of the subject matter described herein may include one or more processors for executing the functions described herein. [0031] Preferably, the wireless signal analyzer may be operative to represent multiple RF receivers with different simulated RF channels interposed between itself and the DUT, each RF channel corresponding to a different RF receiver. The wireless signal analyzer may further be operative to cause the DUT to transmit signals destined for a multiplicity of RF receivers simultaneously. The signal analyzer may be yet further operative to distinguish and decode these signals separately and perform measurements upon the decoded signals. [0032] In accordance with an aspect of another embodiment, a wireless signal analyzer is disclosed that may be operative to perform tests upon MIMO and MU-MIMO receivers in a controlled RF environment. The analyzer may contain: simulated radio channel generation logic to create a statistical model of a simulated RF channel; a transmit precoding matrix function to condition a transmitted test signal according to the properties of the simulated RF channel; sounding protocol logic to perform a sounding packet exchange between the signal analyzer and the DUT containing suitable channel coefficients; and comparison logic to determine the efficacy of the channel estimation implemented by the DUT. [0033] Such a wireless signal analyzer may be operative to represent multiple test signal transmitters with different RF channels between themselves and the DUT, and may further be operative to represent one or more transmitters communicating with multiple counterpart receivers within the DUT. [0034] Advantageously, the coefficients of the sounding packets sent to the DUT may be adjusted to simulate the effect of one or more RF channels interposed between the DUT and the wireless signal analyzer, in a cabled environment without utilizing a channel simulator. [0035] Advantageously, the coefficients of the sounding packets may be adjusted to cause the DUT to perform beamforming according to any simulated RF channel, which may permit increased flexibility in testing beamforming capabilities of the DUT. [0036] Advantageously, the quality of the transmit precoding and beamforming performed within the DUT may be determined by transmitting sounding packets containing known coefficients representing a desired RF channel, causing the DUT to transmit data, decoding the data according to the coefficients of the RF channel, and verifying the quality of the decoded data. [0037] Advantageously, the quality of the channel estimation performed within the DUT may be assessed by transmitting sounding signals that are predistorted in known ways and examining the coefficients within the sounding packets returned by the DUT. [0038] Advantageously, a figure of merit may be measured for the channel estimation performed by a DUT when presented with a channel model by assessing the coefficients of the sounding packets returned by the DUT. [0039] Advantageously, tests may be performed upon a DUT in an MU-MIMO system without requiring multiple channel simulators. [0040] The subject matter described herein may be implemented in hardware, firmware, or software in combination with hardware or firmware. As such, the terms “function” or “module” as used herein refer to hardware, firmware, or software in combination with hardware or firmware for implementing the feature being described. In one exemplary implementation, the subject matter described herein may be implemented using a non-transitory computer readable medium having stored thereon computer executable instructions that when executed by the processor of a computer control the computer to perform steps. Exemplary computer readable media suitable for implementing the subject matter described herein include non-transitory computer-readable media, such as disk memory devices, chip memory devices, programmable logic devices, and application specific integrated circuits. In addition, a computer readable medium that implements the subject matter described herein may be located on a single device or computing platform or may be distributed across multiple devices or computing platforms. BRIEF DESCRIPTION OF THE DRAWINGS [0041] The detailed description herein of the features and embodiments are best understood when taken in conjunction with the accompanying drawings, wherein: [0042] FIG. 1 shows a simplified representation of a MIMO transmitter and MIMO receiver operating in an RF channel environment; [0043] FIG. 2 provides an illustrative view of an exemplary conventional wireless test system for testing a MIMO DUT; [0044] FIG. 3 represents an illustrative view of an exemplary conventional wireless test system used in association with a MIMO channel analyzer to test a MIMO DUT under different RF channel conditions; [0045] FIG. 4 shows a simplified representation of an MU-MIMO RF environment, comprising multiple MU-MIMO RF transmitters concurrently transmitting signals to a MU-MIMO RF receiver; [0046] FIG. 5 provides an exemplary block diagram of a test system for conducting tests on an MU-MIMO DUT, in accordance with conventional systems and methods; [0047] FIG. 6 exemplifies a possible block diagram of an MU-MIMO wireless transmitter and an MU-MIMO wireless receiver; [0048] FIG. 7 represents the steps of an exemplary sounding packet exchange wherein beamforming information is calculated from channel sounding measurements and subsequently used for conditioning transmitted signal data packets; [0049] FIG. 8 is representative of a simplified mathematical model of signal transmission and reception in a MIMO RF channel environment; [0050] FIG. 9 illustrates one possible simplified mathematical model of signal transmission and reception in a MU-MIMO RF channel environment comprising one or more receivers and transmitters; [0051] FIG. 10 shows an example of channel estimation and beamforming feedback in the context of a simplified MU-MIMO RF channel environment, with one or more receivers and transmitters; [0052] FIG. 11 depicts a possible mathematical model of a cabled RF environment applied to a MIMO RF transmitter and receiver; [0053] FIG. 12 exemplifies the extension of the mathematical model for a cabled RF environment extended to include MU-MIMO RF transmitters and receivers; [0054] FIG. 13 depicts an exemplary aspect of a test system that utilizes a simulated channel model and beamforming feedback to perform MU-MIMO tests in a cabled RF environment; [0055] FIG. 14 provides another exemplary aspect of a test system that utilizes a simulated channel model and receive decoder matrix coefficients to perform MU-MIMO tests in a cabled RF environment; [0056] FIG. 15 shows an exemplary aspect of a test system that potentially derives channel estimation error vectors utilizing a simulated channel model together with comparison of beamforming feedback parameters; [0057] FIG. 16 shows an illustrative flow chart of one possible method of obtaining the optimal SNR value for a set of one or more simulated RF channels; and [0058] FIG. 17 depicts an exemplary flow chart for a possible procedure for calculating a Figure of Merit for the channel estimation and beamforming feedback parameters produced by a DUT. [0059] It should be understood that like reference numerals are used to identify like elements illustrated in one or more of the above drawings. DETAILED DESCRIPTION [0060] With reference to FIG. 13 , an aspect of an embodiment of a wireless MU-MIMO test system may comprise MU-MIMO test equipment receiver 251 within a test system that may be connected using RF cables 243 to multiple DUT transmitters 255 , 256 , 257 . If required, RF power combiners may be used to couple together the multiple DUT transmitters without mismatch problems. It should be understood that while FIG. 13 (and subsequent drawings) show transmitters, receivers and cables in sets of three, this is done only for representational convenience, and the principles set forth herein apply to arbitrary numbers of transmitters, receivers and cables. [0061] MU-MIMO receiver 251 may further comprise: receive decoders 213 , 218 , 223 that implement calculated receive decode matrices [U 1 ], [U 2 ], [U 3 ] respectively; channel modeling functions 263 , 264 , 265 ; precode matrix calculation functions 260 , 261 , 262 ; and beamforming feedback functions 234 , 235 , 236 . RF cables 243 may be equivalent to RF channels appearing as three identity matrices [H c ] ( 240 , 241 , 242 ) that may couple the DUT transmitters to the test equipment receiver. Each of DUT transmitters 255 , 256 , 257 may contain separate transmit precoders 252 , 253 , 254 , the coefficients of which may be determined by the beamforming feedback received from beamforming feedback functions 234 , 235 , 236 . [0062] Channel modeling functions 263 , 264 , 265 may generate the parameters of any desired RF channel, and may further generate orthogonal RF channels [H 1 ], [H 2 ], [H 3 ] having orthogonal transmission modes. Normally, precode matrix calculation functions 260 , 261 , 262 may simply calculate actual [V 1 ], [V 2 ], [V 3 ] transmit precoding matrices, as it is assumed that real RF channels corresponding to [H 1 ], [H 2 ], [H 3 ] are interposed between MU-MIMO transmitters and receivers. However, in this aspect, precode matrix calculation functions 260 , 261 , 262 may include the modeled RF channels into the calculation, such that the coefficients transmitted by beamforming feedback functions 234 , 235 , 236 may contain the product of [V 1 ], [V 2 ], [V 3 ] and [H 1 ], [H 2 ], [H 3 ] respectively. When these coefficients are sent to DUT transmitters 255 , 256 , 257 , they may configure transmit precoders 252 , 253 , 254 with the appropriate products as shown. [0063] DUT transmitters 255 , 256 , 257 may drive transmit signals through cables 243 to MU-MIMO receiver 251 . The effect upon each transmitted signal is to multiply it with the identity matrix [H c ], which leaves the transmitted signal unchanged. It will be appreciated upon comparison of FIG. 9 and FIG. 13 that transmit data signals [x 1 ], [x 2 ], [x 3 ] ( 210 , 215 , 220 respectively) after processing in this fashion by transmit precoders 252 , 253 , 254 and transmission to MU-MIMO receiver 251 may now represent the effect of having passed through three orthogonal RF channels [H 1 ], [H 2 ], [H 3 ]. It will be further appreciated that external channel simulators (such as those shown in FIG. 5 ) may not be required between DUT transmitters 255 , 256 , 257 and MU-MIMO receiver 251 to achieve this effect. Instead, transmit precoders 252 , 253 , 254 within DUT transmitters 255 , 256 , 257 have accomplished the same effect, considerably reducing the system cost. It will yet further be appreciated that the adverse effects of coupling multiple channel simulators as depicted in FIG. 5 are not present, in spite of the cabled coupling of all the DUT transmitters 255 , 256 , 257 . [0064] Receive decoders 213 , 218 , and 223 may include signal processing functions responsive to signals transmitted by the DUT and coupled to a respective one of the channel modeling functions 263 , 264 , and 265 . Each signal processing function is operative to simulate the effect of a modeled RF channel on the signals transmitted by said DUT. The signal processing function simulates the effect of the modeled RF channel by applying the [U] decode matrix to the received signal. [0065] Turning now to FIG. 14 , an aspect of another embodiment of a wireless MU-MIMO test system may comprise a DUT 258 and MU-MIMO test system 251 . DUT 258 may contain one or more MU-MIMO transmit chains accepting separate input signals [x 1 ], [x 2 ], [x 3 ] ( 210 , 215 , 220 respectively), that may be processed by transmit precoders 252 , 253 , 254 that are configured with matrices [V 1 ], [V 2 ], [V 3 ] respectively. The outputs of the transmit precoders may be coupled together within DUT 258 to drive a single set of cables 245 , whose RF propagation matrix 244 may be represented by [H e ] (an identity matrix). These cables may in turn be coupled to MU-MIMO test equipment receiver 251 , which may contain receive decoders 213 , 218 , 223 that accept and process the signals from cables 245 to generate independent output signals [y 1 ], [y 2 ], [y 3 ] ( 214 , 219 , 224 respectively). Channel modeling functions 263 , 264 , 265 may be used to set up receive decoders 213 , 218 , 223 , as well as to drive precode matrix calculation functions 260 , 261 , 262 respectively. Beamforming feedback functions 234 , 235 , 236 may pass beamforming feedback generated by precode matrix calculation functions 260 , 261 , 262 to DUT 258 , and this feedback may be used to configure transmit precoders 252 , 253 , 254 . [0066] In this aspect, the beamforming feedback to the DUT transmitters may be used to set up transmit precoders 252 , 253 , 254 with the coefficients of the [V 1 ], [V 2 ], [V 3 ] matrices, as may be performed in a normally operating MU-MIMO transmitter. Therefore, the channel models generated by channel modeling functions 263 , 264 , 265 may be used in the same manner as measured channel estimates 230 , 231 , 232 in FIG. 10 . However, the channel modeling functions 263 , 264 , 265 may further be used to configure receive decoders 213 , 218 , 223 with the product of the simulated RF channel matrices [H 1 ], [H 2 ], [H 3 ] and corresponding receive decode matrices [U 1 ], [U 2 ], [U 3 ]. This may have the effect of configuring orthogonal channels between different transmitter/receiver pairs, and may thereby preserve the ability of the system to support MU-MIMO operation. [0067] The system depicted in FIG. 14 may be used for several purposes. As an example of one such application, test equipment 251 may measure the quality of the transmit precoding performed by DUT 258 , by the steps of: a) generating different RF channel matrices [H 1 ], [H 2 ], [H 3 ] in channel modeling functions 263 , 264 , 265 ; b) performing the precode matrix calculation in 260 , 261 , 262 and returning sounding signals via beamforming feedback functions 234 , 235 , 236 ; b) causing DUT 258 to transmit known data [x 1 ], [x 2 ], [x 3 ]; c) decoding the signals received from DUT 258 with the correct set of RF channel matrices [H 1 ], [H 2 ], [H 3 ] and receive decode matrices [U 1 ], [U 2 ], [U 3 ]; and d) comparing the signals [y 1 ], [y 2 ], [y 3 ] against the known data [x 1 ], [x 2 ], [x 3 ] to obtain an error metric, one example of which may be the bit error ratio (BER); Test equipment 251 may use an arbitrary number of complex channel models to determine the capacity of DUT 258 to handle these types of RF channels accurately. [0073] As an example of another application, it may be desirable to simulate the effect of multiple stations (such as wireless clients) at test equipment 251 when testing DUT devices 258 such as APs. In this case, the system may cause channel modeling functions 263 , 264 , 265 to generate multiple RF channel models. Each modeled channel may represent the RF propagation between DUT 258 and one of the multiple simulated stations. The system may further present the precode matrices resulting from these multiple channels to DUT 258 in succession, possibly using separate beamforming exchanges. After this, the system may cause DUT 258 to transmit test traffic to all of the simulated stations, and verify that DUT 258 uses the correct precode matrix for each of these simulated stations. This may enable the test system to verify the station capacity supported by DUT 258 . An example of one means of determining the station capacity is by increasing the number of simulated stations until DUT 258 fails to use the correct precode matrices when transmitting test traffic. [0074] As an example of yet another application, it may be useful to determine whether DUT 258 is capable of quickly responding to RF channel variations over time. Such variations may correspond to those caused by Doppler shifts due to relative motion. In this example, test equipment 251 may cause channel modeling functions 263 , 264 , 265 to generate time-varying simulated RF channels, which may then be processed by precode matrix calculation functions 260 , 261 , 262 to produce transmit precoder coefficients which may then be sent to DUT 258 by beamforming feedback functions 234 , 235 , 236 . An error metric, which may include the BER, may be used to determine the ability of DUT 258 to respond quickly and accurately to RF channel variations. [0075] FIG. 15 depicts an aspect of another embodiment of an MU-MIMO test transmitter 292 within a wireless MU-MIMO test system, which may be used to quantify the channel estimation error within the receiver 293 of an MU-MIMO DUT. This aspect may include input test signals [x 1 ], [x 2 ], [x 3 ] ( 210 , 215 , 220 respectively); transmit precoders 252 , 253 , 254 ; channel modeling functions 280 , 281 , 282 , each of which may model any desired RF channel and may generate RF channel matrices [H 1 ], [H 2 ], [H 3 ]; and beamforming feedback coefficient comparators 283 , 284 , 285 , which may compare expected coefficients corresponding to the modeled RF channels with actual coefficients returned by DUT 293 , and may further generate error signals 297 , 298 , 299 . It is understood that other functions may also be performed within transmitter 292 , but are not relevant to this discussion and are therefore omitted. [0076] DUT receiver 293 may perform the standard MU-MIMO channel estimation and beamforming feedback processes, and may include receive decoders 213 , 218 , 223 , that may process received signals with receive decoder matrices [U 1 ], [U 2 ], [U 3 ] to produce output signals [y 1 ], [y 2 ], [y 3 ] ( 214 , 219 , 224 respectively). DUT receiver 293 may further include channel estimation functions 289 , 290 , 291 and beamforming feedback functions 294 , 295 , 296 that may serve to return transmit precoder coefficients to MU-MIMO test transmitter 292 . [0077] In operation, channel modeling functions 280 , 281 , 282 may generate any desired set of RF channels [H 1 ], [H 2 ], [H 3 ], which may then be multiplied into a set of optimal transmit precoding matrices [V 1 ], [V 2 ], [V 3 ] and configured into transmit precoders 252 , 253 , 254 . Known test signals [x 1 ], [x 2 ], [x 3 ] ( 210 , 215 , 220 respectively) may then be passed into transmit precoders 252 , 253 , 254 , combined via cables 247 and driven to DUT receiver 293 . The cables 247 may present a single RF channel 246 , which may be an identity matrix [H c ]. These signals may be received by each of the receive chains within DUT 293 . A beamforming information exchange process or beamforming training sequence may then be performed between each transmitter/receiver pair by channel estimation functions 289 , 290 , 291 and beamforming feedback functions 294 , 295 , 296 . As the RF channels [H 1 ], [H 2 ], [H 3 ] may be known in advance by MU-MIMQ transmitter 292 , the coefficients expected to be fed back during the beamforming exchange may likewise be precalculated by channel modeling functions 280 , 281 , 282 . These coefficients may be passed to comparators 283 , 284 , 285 , which may compare them to the coefficients actually fed back by DUT receiver 293 , and may generate error signals 297 , 298 , 299 . An assessment of these error signals may provide an indication of the quality of the channel estimation that may be performed by DUT receiver 293 . Further, such an assessment may be performed for different modeled RF channels [H 1 ], [H 2 ], [H 3 ], which may provide a quantitative assessment of the ability of DUT receiver 293 to cope with a wide variety of RF channel conditions. [0078] An example of another application of the aspect depicted in FIG. 15 may be to determine the ability of DUT receiver 293 to handle channel estimation and beamforming feedback for a large number of transmitters with a correspondingly large number of different RF channels between each transmitter/receiver pair. In this application, channel modeling functions 280 , 281 , 282 may be configured to successively generate different RF channel models, and each channel model may correspond to a different simulated transmitter. Test equipment transmitter 292 may then perform sounding packet exchanges with DUT receiver 293 to cause channel estimation and beamforming information exchange to occur between each of these simulated transmitters and DUT receiver 293 . DUT receiver 293 may then store the required [U] matrix for subsequent use when receiving data from that specific simulated transmitter. MU-MIMO test transmitter 292 may then cycle through the [H] and [V] matrices for each of the simulated transmitters, and may further transmit test signals [x] to determine if DUT receiver 293 can identify and configure the correct [U] matrix into receive decoders 213 , 218 , 223 . Determination of whether DUT receiver 293 has successfully identified the simulated transmitter and use the correct [U] matrix may be performed by analyzing the receive signal [y]. One possible analysis method is to compare the received signal [y] with the transmitted test signal [x]. [0079] In situations where it may become necessary to quantitatively assess the efficacy of the channel estimation and beamforming calculations performed by an MU-MIMO DUT, it may be desirable to develop a Figure Of Merit (FOM) for the combined process. The FOM weighs the SNR achievable using the parameters calculated by the DUT against the SNR achieved for the same test signals using the same RF channel but with a known optimal algorithm. One possible example of such an algorithm is a water-filling algorithm. For example, in the MU-MIMO case, the SNR may be expressed as E b /N o , which is the ratio of the signal energy per bit of transmitted data to the specific noise power, at a specific value of an error metric, which may be the BER. It may be possible to calculate the FOM using the arrangement of FIG. 15 , for some predetermined simulated RF channels described by matrices [H 1 ], [H 2 ], [H 3 ]. [0080] Turning now to FIG. 16 , a flowchart of an exemplary iterative procedure for obtaining the optimal SNR and transmit precoding matrices for a set of simulated RF channels [H 1 ], [H 2 ], [H 3 ] and a set of test signals [x 1 ], [x 2 ], [x 3 ] at a predetermined value of an error metric is depicted. The procedure illustrated in FIG. 16 may be implemented by emulated MU-MIMO transmitter 292 illustrated in FIG. 15 where precoders 252 , 253 , and 254 cycle through [V] matrices until an optimal [V] matrix is found. Alternatively, the procedure illustrated in FIG. 16 may be performed by emulated MU-MIMO receiver 251 illustrated in FIG. 13 in combination with a real or emulated MIMO transmitter. As such, MU-MIMO receiver 251 may include an SNR calculation function that calculates the SNR for each iteration of the test, an SNR of different iterations of the test, and saving the precoding matrix that generates the optimal SNR. Precoding matrix calculation functions 260 , 261 , and 262 may be configured to compute the set of precoding matrices [V 1 ], [V 2 ] and [V 3 ] used in each test iteration. Receive decoders 213 , 218 , and 233 may calculate the receive decoder matrices [U 1 ], [U 2 ], and [U 3 ] based on the modeled channel matrices [H 1 ], [H 2 ], and [H 3 ]. The procedure illustrated in FIG. 16 may follow the steps of: a) At step 300 , beginning the process; b) At step 301 , generating a set of modeled RF channel matrices [H 1 ], [H 2 ], [H 3 ]; c) At step 302 , computing a set of candidate transmit precoding matrices [V 1 ], [V 2 ], [V 3 ] that match the RF channel matrices; d) At step 303 , computing the corresponding set of candidate receive decoding matrices [U 1 ], [U 2 ], [U 3 ] e) At step 304 , using a system model, that may be similar to that depicted in FIG. 9 , to calculate the SNR of a predetermined test signal, which may be the E b /N o value required for a predetermined value of the error metric; f) At step 305 , determining whether the SNR so calculated is improved (i.e., is lower than) all previously calculated SNR values; g) At step 306 , if the SNR is in fact improved, saving the SNR value as the best candidate and also saving the corresponding candidate transmit precoding matrices [V 1 ], [V 2 ], [V 3 ] h) At step 307 , determining if more iterations are required, in which case the procedure may return to step 302 to calculate a new set of candidate precoding matrices [V 1 ], [V 2 ], [V 3 ], and may repeat steps 303 through 306 to determine the corresponding SNR value; i) At step 308 , recording the last saved value from step 306 as the optimal SNR value, and the corresponding transmit precoding matrices as the optimal precoding matrices; and j) At step 309 , terminating the process. [0091] Upon calculating an optimal SNR value and corresponding transmit precoding matrices, FIG. 17 may depict one possible procedure for calculating the combined FOM for the channel estimator and beamforming calculator of a DUT receiver, for example DUT receiver 293 shown in FIG. 15 . The procedure may be performed for the same modeled RF channels [H 1 ], [H 2 ], [H 3 ] and test signals [x 1 ], [x 2 ], [x 3 ] as used in the procedure depicted in FIG. 16 . The procedure may take the steps of: a) At step 320 , beginning the process; b) At step 321 , generating predetermined sounding signals [S 1 ], [S 2 ], [S 3 ] according to some predetermined beamforming information exchange process; c) At step 322 , processing these predetermined sounding signals as if they had been transmitted over the set of simulated RF channels; d) At step 323 , transmitting these processed signals to the DUT (for example, DUT receiver 293 ) as part of a beamforming exchange; e) At step 324 , receiving beamforming feedback from the DUT, containing transmit preceding matrix coefficients; f) At step 325 , using this beamforming feedback to set up transmit preceding matrices [V 1 ], [V 2 ], [V 3 ] and corresponding receive decoding matrices [U 1 ], [U 2 ], [U 3 ], possibly in an MU-MIMO system model, for example that depicted in FIG. 9 ; g) At step 326 , generating test signals [x 1 ], [x 2 ], [x 3 ]; h) At step 327 , injecting test signals [x 1 ], [x 2 ], [x 3 ] into the MU-MIMO system model, and simulating the effect of the matrices [V 1 ], [V 2 ], [V 3 ], [H 1 ], [H 2 ], [U 1 ], [U 2 ], [U 3 ] on the test signals, which may include the step of calculating the SNR (such as the Eb/No for a predetermined value of an error metric such as the BER); i) At step 328 , determining the FOM by comparing the SNR determined at step 327 with the optimal SNR, which may be determined according to step (h) of the procedure depicted in FIG. 16 ; and j) At step 329 , terminating the process. [0102] It will be apparent to those of ordinary skill in the art that, in accordance with embodiments described herein, the generation of beamforming feedback coefficients in a MIMO or MU-MIMO test system from modeled or modified RF channel parameters may facilitate a number of useful test functions. These functions may include the use of arbitrary RF channel models, even in a cabled environment. It will be further apparent that such functions may not require the use of external channel simulators. It will be yet further apparent that arbitrary but well-defined RF channel models may be interposed between transmitter/receiver pairs. Advantageously, this may enable the testing of MIMO or MU-MIMO functionality, including beamforming, in a fully cabled environment with reduced cost and complexity, and may improve the ability to test MIMO and MU-MIMO functions in an automated manner. [0103] It will be appreciated by those of ordinary skill in the art that, in accordance with aspects of embodiments described herein, the simulation of arbitrary RF channels between MIMO or MU-MIMO transmitter/receiver pairs may be performed on either the transmitter side or on the receiver side. Advantageously, this may increase the flexibility of the test setup and enable different types of DUTs to be tested. [0104] It will also be appreciated by those of ordinary skill in the art that, in accordance with embodiments described herein, the efficacy of the channel estimation performed within the DUT may be assessed against an arbitrary set of RF channel models. It will be further appreciated that the efficacy of the transmit precoding calculations performed by the DUT may be quantitatively assessed. It will be yet further appreciated that, in accordance with the embodiments described herein, an FOM may be determined for the absolute quality of the channel estimation and beamforming calculations performed by a MIMO or MU-MIMO DUT. Advantageously, this may enable the testing of essential MIMO or MU-MIMO internal DUT functions. [0105] Accordingly, while the subject matter herein has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the illustrative embodiments, as well as other aspects or embodiments of the subject matter described herein, will be apparent to persons of ordinary skill in the art upon reference to this description. These modifications shall not be construed as departing from the scope of the subject matter described herein, which is defined solely by the claims appended hereto.

Systems and methods are disclosed herein to provide communication test systems for the testing of multiple-input multiple-output (MIMO) radio frequency wireless data communication devices, systems and networks, including Multi-User MIMO (MU-MIMO) devices and systems. In accordance with one or more embodiments, a test system containing an integrated MIMO signal analyzer is disclosed that includes a protocol engine operative in conjunction with a waveform generator and waveform analyzer that analyzes the signal waveform of a device under test. Such a test system may offer improved capabilities such as a simpler and more flexible measurement of complex MIMO signal waveforms, more automated measurements of MIMO waveforms including beamforming functions, and more accurate measurement of the efficiency of MIMO related functions such as channel estimation, transmit precoding and beamforming.

RELATED APPLICATIONS [0001] This application claims the benefit of provisional U.S. patent application Ser. No. 61/394,166 filed on Oct. 18, 2010 for HIGH REFRACTIVE INDEX GLASS COMPOSITION, the entire disclosure of which is fully incorporated herein by reference. TECHNICAL FIELD [0002] The present invention relates generally to a glass composition, and more particularly, to a glass composition for forming high refractive index glass fibers. The glass fibers may be used to reinforce plastics and form a composite having a high refractive index. These high refractive index composites may then be used in applications where high strength and transparency are required. BACKGROUND [0003] Glass fibers are manufactured from various raw materials combined in specific proportions to yield a desired chemical composition. This collection of materials is commonly termed a “glass batch.” To form glass fibers, typically the glass batch is melted in a melter or melting apparatus, the molten glass is drawn into filaments through a bushing or orifice plate, and a sizing composition containing lubricants, coupling agents and film-forming binder resins is applied to the filaments. After the sizing is applied, the fibers may be gathered into one or more strands and wound into a package or, alternatively, the fibers may be chopped while wet and collected. The collected chopped strands may then be dried and cured to form dry chopped fibers or they can be packaged in their wet condition as wet chopped fibers. The fibers, in turn, may be used to reinforce plastics and various other structural and non-structural products. [0004] The composition of the glass batch and the glass manufactured from it are generally expressed in terms of percentages of the components and are mainly expressed as oxides. Compounds such as SiO 2 , Al 2 O 3 , CaO, MgO, B 2 O 3 , La 2 O, Nb 2 O 5 , Ta 2 O 5 , ZrO 2 , 2 O 3 , Li 2 O, Na 2 O, GdO 3 , BaO, SrO, ZnO, ZrO 2 , P 2 O 5 , GeO 2 , WO 3 , Fe 2 O 3 , fluorine, and SO 3 may be used to form a glass batch. Numerous types of glasses may be produced from varying the amounts of these oxides, or eliminating some of the oxides in the glass batch. Normal reinforcement glasses such as R-glass, E-glass, S-glass, A-glass, C-glass, and ECR-glass may be formed from certain combinations of the oxides. In addition, optical glasses having a desired refractive index can be produced by choosing oxides for the glass batch. The glass composition controls the forming and product properties of the glass. Characteristics of glass compositions include the raw material cost and environmental impact. [0005] High refractive index glasses and use thereof in optical lens applications are known in the art. However, conventional optical glass fibers are unable to be formed by conventional fiberizing techniques because they lack sufficient viscosity above their crystallization temperature to be formed into fibers. Thus, although high refractive index glasses exist, there remains a need in the art for glass compositions that possess a high refractive index, an Abbe number and a coefficient of thermal expansion that is appropriate for the reinforcement of high refractive index plastics, and a viscosity above the liquidus temperature that is sufficiently high to permit the formation of fibers using conventional fiber forming techniques. SUMMARY OF THE INVENTION [0006] The general inventive concepts include a composition that includes SiO 2 in an amount from 30.0 to 40.0% by weight, Al 2 O 3 in an amount from 15.0 to 23.0% by weight, B 2 O 3 in an amount from 0.0 to 15.0% by weight, K 2 O in an amount from 0.0 to 5.0% by weight, La 2 O 3 in an amount from 0.0 to 30.0% by weight, Li 2 O in an amount from 0.0 to 3.0% by weight, Na 2 O in an amount from 0.0 to 4.0% by weight, Nb 2 O 5 in an amount from 0.0 to 10.0% by weight, TiO 2 in an amount from 0.0 to 7.5% by weight, WO 3 in an amount from 0.0 to 10.0% by weight, Y 2 O 3 in an amount from 15.0 to 35.0% by weight, and RO in an amount from 0.0 to 7.5% by weight, where RO is one or more of MgO, CaO, SrO, and BaO. The phrase “% by weight”, as used herein, is intended to be defined as the percent by weight of the total composition. [0007] In some exemplary embodiments, the composition also contains trace quantities of other components or impurities that are not intentionally added. Also, in some exemplary embodiments, the glass composition is free or substantially free of fluorine and lead. [0008] In some exemplary embodiments, glass fibers formed from the composition have a refractive index between 1.55 and 1.69, an Abbe number less than about 65, and a coefficient of thermal expansion (CTE) less than about 66×10 −7 cm/cm. Further, the glass composition and fibers produced therefrom possess a CTE and an Abbe number that may be suitable for reinforcing high refractive index plastics. [0009] In some exemplary embodiments, the glass composition possesses a viscosity above the liquidus temperature that is sufficiently high to permit the glass fibers to be formed using conventional fiber forming techniques, such as, for example, a platinum-lined melter. [0010] In some exemplary embodiments, a reinforced composite is formed from a matrix material and a plurality of fibers formed from the composition described. The matrix material may be any suitable thermoplastic or thermoset resin known to those of skill in the art, and includes thermoplastics and thermoset resins such as polyesters, polypropylene, polyamide, polyethylene terephthalate, polybutylene, polysulfone, polyethersulfone, polyether imide, polyarylate, epoxy resins, unsaturated polyesters, phenolics, vinylesters, and elastomers. The polymer resins can be used alone or in combination to form the final composite product. [0011] In some exemplary embodiments, glass fibers formed from the inventive compositions have a liquidus temperature no greater than about 1531° C., a log 3 temperature less than about 1443° C., and a ΔT up to about 77° C. [0012] In yet other exemplary embodiments, glass fibers formed from the inventive composition have a refractive index between about 1.55 and about 1.69, preferably from about 1.55 to about 1.65. [0013] In further exemplary embodiments, glass fibers formed from the inventive composition have an Abbe number less than about 65, preferably less than about 60, and a coefficient of thermal expansion less than about 66×10″ 7 cm/cm, preferably less than about 55×10 −7 cm/cm. [0014] In some exemplary embodiments, the difference between the forming temperature and the crystallization temperature is from about −170° C. to about 77° C. [0015] The foregoing and other objects, features, and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description that follows. DETAILED DESCRIPTION [0016] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein. All references cited herein, including published or corresponding U.S. or foreign patent applications, issued U.S. or foreign patents, and any other references, are each incorporated by reference in their entireties, including all data, tables, figures, and text presented in the cited references. The terms “composition” and “formulation” may be used interchangeably herein. Additionally, the phrase “inventive glass composition” and “glass composition” may be interchangeably used. [0017] The general inventive concepts relate to a glass composition used to form continuous glass fibers that may be used to reinforce high refractive index polymer matrices and form transparent or translucent composite products. In addition, the glass composition has a viscosity that is sufficiently above the liquidus temperature to permit the glass fibers to be fowled using currently available fiber forming techniques, such as, for example, a platinum-lined melter. [0018] In some exemplary embodiments, the inventive glass composition includes the following components in the weight percent ranges given in Table 1. As used herein, the terms “weight percent” and “percent by weight” may be used interchangeably and are meant to denote the weight percent (or percent by weight) based on the total composition. [0000] TABLE 1 % by Chemical weight SiO 2 30.0-40.0 Al 2 O 3 15.0-23.0 B 2 O 3  0.0-15.0 K 2 O 0.0-5.0 La 2 O 3  0.0-30.0 Li 2 O 0.0-3.0 Na 2 O 0.0-4.0 Nb 2 O 5  0.0-10.0 TiO 2 0.0-7.5 WO 3  0.0-10.0 Y 2 O 3 15.0-35.0 MgO + CaO + SrO + BaO 0.0-7.5 [0019] In some exemplary embodiments, the glass composition includes the components set forth in Table 2. [0000] TABLE 2 % by Chemical weight SiO 2 30.0-33.0 Al 2 O 3 16.0-22.0 B 2 O 3  5.0-10.0 La 2 O 3 10.0-26.0 Nb 2 O 5 0.0-2.0 TiO 2 0.0-1.5 Y 2 O 3 17.0-33.0 [0020] Further, it is to be appreciated that impurities or trace materials may be present in the glass composition without adversely affecting the glasses or the fibers. These impurities may enter the glass as raw material impurities or may be products formed by the chemical reaction of the molten glass with furnace components. Non-limiting examples of trace materials include Fe 2 O 3 , Cr 2 O 3 , CeO 2 , Pr 2 O 3 , Nd 2 O 3 , Pm 2 O 3 , Sm 2 O 3 , Eu 2 O 3 , Gd 2 O 3 , Tb 2 O 3 , Dy 2 O 3 , Ho 2 O 3 , Er 2 O 3 , Tm 2 O 3 , Yb 2 O 3 and Lu 2 O 3 , all of which are present in their oxide forms, and fluorine and chlorine. [0021] The glass fibers produced from the inventive composition may have a refractive index between about 1.55 and about 1.69, an Abbe number less than about 65, and a coefficient of thermal expansion less than about 66×10 −7 cm/cm. In some exemplary embodiments, the glass fibers have a refractive index between about 1.55 and about 1.65, an Abbe number less than about 55, and a coefficient of thermal expansion less than about 52×10 −7 cm/cm. The difference between the forming temperature and the crystallization temperature is from about −170° C. to about 77° C. Also, the viscosity as a function of temperature of the glass is such that glass fibers formed from the inventive composition may be formed in conventional platinum-lined melters (e.g., paramelters). [0022] In the glass composition, SiO 2 , Y 2 O 3 , and B 2 O 3 provide a glass network for the fiber. The SiO 2 also plays a role in the chemical and thermal stability of the formed glass fiber. La 2 O, Nb 2 O 5 , and Y 2 O 3 are effective for increasing the refractive index of the glass fiber. TiO 2 is optionally added to adjust the refractive index and Abbe number. Al 2 O 3 may be added to improve the chemical durability of the glass fiber. In some exemplary embodiments, the glass composition is free or substantially free of fluorine and lead, although either may be added at levels less than about 1% without adversely affecting the glass properties. [0023] The fiberizing properties of the glass composition of the present invention include the fiberizing temperature, the liquidus temperature, and ΔT. The fiberizing temperature is defined as the temperature that corresponds to a viscosity of about 1000 Poise. Lowering the fiberizing temperature may reduce the production cost of the glass fibers because it allows for a longer bushing life and reduced energy usage. For example, at a lower fiberizing temperature, a bushing operates at a cooler temperature and does not quickly “sag”. Sag is a phenomenon that occurs in bushings that are held at an elevated temperature for extended periods of time. Thus, by lowering the fiberizing temperature, the sag rate of the bushing may be reduced and the bushing life can be increased. In the present invention, the glass composition has a fiberizing temperature (i.e., log 3 temperature) that is less than about 1443° C. In exemplary embodiments, the log 3 temperature is from about 1081° C. to about 1443° C. [0024] The liquidus temperature is defined as the highest temperature at which equilibrium exists between liquid glass and its primary crystalline phase. At all temperatures above the liquidus temperature, the glass is free from crystals in its primary phase. At temperatures below the liquidus temperature, crystals may form. Additionally, the liquidus temperature is the greatest temperature at which devitrification can occur upon cooling the glass melt. At all temperatures above the liquidus temperature, the glass is completely molten. In exemplary embodiments, the liquidus temperature of the inventive composition may range from about 1169° C. to about 1531° C. [0025] A third fiberizing property is “ΔT”, which is defined as the difference between the fiberizing temperature (i.e., log 3 temperature) and the liquidus temperature. If the ΔT is too small, the molten glass may crystallize within the fiberizing apparatus and cause a break in the manufacturing process. Additionally, glasses with small or negative ΔT values may be formed utilizing methods that are not commonly employed when forming reinforcement fibers. For instance, discontinuous fibers may be generated by blowing gas or steam through a molten stream of glass. These discontinuous fibers require additional processing (such as carding or needle felting) to form them into suitable reinforcement fibers. Alternatively, continuous fibers can be formed from glasses having small or negative ΔT values by elevating the forming temperature well above the log 3 temperature. The temperature chosen needs to be above the liquidus temperature to prevent devitrification. The inventive composition may have a ΔT up to about 77° C., in exemplary embodiments, from about −170° C. to about 77° C. [0026] In general, glass fibers according to the present invention may be formed by obtaining the raw materials or ingredients and mixing or blending the components in a conventional manner in the appropriate quantities to give the desired weight percentages of the final composition. For example, the components may be obtained from suitable ingredients or raw materials including, but not limited to, sand or pyrophyllite for SiO 2 , kaolin, alumina or pyrophyllite for Al 2 O 3 , lithium carbonate or spodumene for Li 2 O and sodium feldspar, sodium carbonate or sodium sulfate for Na 2 O, potassium feldspar or potassium carbonate for K 2 O, Lanthanum oxide or Rare Earth Oxide blends for La 2 O 3 , rutile or ilmenite for TiO 2 , and the remainder of the composition is supplied by refined oxides of Nb 2 O 5 , WO 3 , or Y 2 O 3 . Glass cullet can also be used to supply one or more of the needed oxides. [0027] The mixed batch is then melted in a platinum-lined melter, and the resulting molten glass is passed into bushings (e.g., platinum-alloy based bushings). The operating temperatures of the glass in the furnace and bushing are selected to appropriately adjust the viscosity of the glass, and may be maintained using suitable methods such as control devices. Preferably, the temperature at the front end or bottom of the melter is automatically controlled to reduce or eliminate devitrification. The molten glass is then pulled (drawn) through holes or orifices in the bottom or tip plate of the bushing to form glass fibers. The streams of molten glass flowing through the bushing orifices are attenuated to filaments by winding a strand formed of a plurality of individual filaments on a forming tube mounted on a rotatable collet of a winding machine or chopped at an adaptive speed. [0028] The fibers may be further processed in a conventional manner suitable for the intended application. For instance, the continuous glass fibers may be sized with a sizing composition known to those of skill in the art. The sizing composition is in no way restricted, and may be any sizing composition suitable for application to glass fibers. The sized fibers may be used for reinforcing substrates, such as a variety of plastics, where the end product is desired to have a high refractive index. Such applications include, but are not limited to, the reinforcement of high refractive index plastics that have high strength and temperature resistance useful for laboratory equipment or a protective layer for flexible LCD screens. In this regard, the present invention also includes a composite material having a high refractive index that includes the inventive glass fibers, as described above, in combination with a hardenable matrix material. The matrix material may be any suitable thermoplastic or thermoset resin known to those of skill in the art, such as, but not limited to thermoplastics and thermoset resins such as polyesters, polypropylene, polyamide, polyethylene terephthalate, polybutylene, polysulfone, polyethersulfone, polyether imide, polyarylate, epoxy resins, unsaturated polyesters, phenolics, vinylesters, and elastomers. The polymer resins can be used alone or in combination to form the final composite product. [0029] Having generally described this invention, a further understanding can be obtained by reference to certain specific examples illustrated below which are provided for purposes of illustration only and are not intended to be all inclusive or limiting unless otherwise specified. EXAMPLES Example 1 High Refractive Glass Compositions [0030] Glass compositions according to the present invention were made by mixing reagent grade chemicals in proportioned amounts to achieve a final glass composition with the oxide weight percentages set forth in Tables 3-15. The raw materials were melted in a platinum crucible in an electrically heated furnace at a temperature of 1650° C. for 3 hours. The Abbe number was calculated from the refractive index of the glass measured at three wavelengths, 589.2 nm (d), 486.1 nm (F), and 656.3 nm (C). The Abbe number, V, was then calculated from the following equation: [0000] V = n d - 1 n F - n c [0000] The coefficient of thermal expansion was measured by linear extension according to ASTM E228-06. The refractive index was measured using temperature controlled standardized immersion oils according to ASTM E1967-98. The forming viscosity (i.e., the temperature that corresponds to a viscosity of about 1000 Poise) was measured using a rotating cylinder method (ASTM C965). The liquidus temperature was measured by exposing glass to a temperature gradient in a platinum-alloy boat for 16 hours (ASTM C829). Density was measured by the Archimedes method (ASTM C693-93). The modulus was measured indirectly by measuring the speed of sound in a fiber with a known density. [0000] TABLE 3 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 20.76 20.76 20.76 20.76 19.67 19.67 19.67 B 2 O 3 5.00 0.00 0.00 0.00 10.00 0.00 0.00 MgO + CaO + 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SrO + BaO K 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 La 2 O 3 0.00 5.00 0.00 0.00 0.00 10.00 0.00 Li 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nb 2 O 5 0.00 0.00 0.00 5.00 0.00 0.00 0.00 SiO 2 39.76 39.76 39.76 39.76 37.67 37.67 37.67 TiO 2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 WO 3 0.00 0.00 5.00 0.00 0.00 0.00 10.00 Y 2 O 3 34.48 34.48 34.48 34.48 32.67 32.67 32.67 Property Abbe Number 56.1 58.5 58 (FU) Refractive 1.6190 1.6475 1.6405 1.6503 1.6060 1.6596 1.6500 Index (BA) CTE 46 46.6 46.8 50.3 39.4 47 (cm × 10 −7 /cm) Log 3 1268 1386 1302 1245 1385 Temp (° C.) Liquidus Temp 1302 1418 1439 1458 1264 1413 (° C.) ΔT (° C.) −34 −32 −137 −28 [0000] TABLE 4 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex. 13 Ex. 14 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 19.67 19.34 17.26 22.26 16.01 16.01 16.01 B 2 O 3 0.00 5.00 10.00 8.75 15.00 8.75 8.75 MgO + CaO + 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SrO + BaO K 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 La 2 O 3 0.00 6.50 11.00 9.75 9.75 16.00 9.75 Li 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nb 2 O 5 10.00 0.00 0.00 0.00 0.00 0.00 0.00 SiO 2 37.67 37.04 33.06 31.82 31.82 31.82 38.07 TiO 2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 WO 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Y 2 O 3 32.67 32.12 28.67 27.42 27.42 27.42 27.42 Property Abbe Number 57.5 52.5 52.4 53.8 43.8 (FU) Refractive 1.6684 1.6340 1.6330 1.6346 1.6200 1.6516 1.6190 Index (BA) CTE 43.1 52 53.4 43.3 49 43.7 43.5 (cm × 10 −7 /cm) Log 3 1443 1279 1190 1207 1161 1185 1255 Temp (° C.) Liquidus Temp 1531 1303 1194 1311 1199 1257 1233 (° C.) ΔT (° C.) −88 −24 −4 −103 −38 −72 22 [0000] TABLE 5 Ex. 15 Ex. 16 Ex. 17 Ex. 18 Ex. 19 Ex. 20 Ex. 21 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 16.01 16.76 16.76 16.76 16.26 16.26 16.26 B 2 O 3 8.75 9.50 9.50 9.50 9.00 9.00 9.00 MgO + CaO + 0.00 2.50 0.00 0.00 5.00 0.00 0.00 SrO + BaO K 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 La 2 O 3 9.75 10.50 10.50 10.50 10.00 10.00 10.00 Li 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nb 2 O 5 0.00 0.00 0.00 2.50 0.00 0.00 5.00 SiO 2 31.82 32.57 32.57 32.57 32.07 32.07 32.07 TiO 2 0.00 0.00 2.50 0.00 0.00 5.00 0.00 WO 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Y 2 O 3 33.67 28.17 28.17 28.17 27.67 27.67 27.67 Property Abbe Number 49.7 48.5 53.6 63.8 57.6 46.9 49.9 (FU) Refractive Index 1.6516 1.6347 1.6480 1.6440 1.6399 1.6620 1.6530 (BA) CTE 43.8 42.5 49.7 50.4 50.5 46.8 44.5 (cm × 10 −7 /cm) Log 3 1184 1191 1179 1184 1193 1174 1209 Temp (° C.) Liquidus Temp 1284 1256 1223 1225 1265 1252 1371 (° C.) ΔT (° C.) −100 −64 −44 −41 −72 −77 −162 [0000] TABLE 6 Ex. 22 Ex. 23 Ex. 24 Ex. 25 Ex. 26 Ex. 27 Ex. 28 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 15.76 15.76 15.76 16.26 16.26 16.26 15.76 B 2 O 3 8.50 8.50 8.50 9.00 9.00 9.00 8.50 MgO + CaO + 7.50 0.00 0.00 2.50 2.50 0.00 2.50 SrO + BaO K 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 La 2 O 3 9.50 9.50 9.50 10.00 10.00 10.00 9.50 Li 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nb 2 O 5 0.00 0.00 7.50 0.00 2.50 2.50 2.50 SiO 2 31.57 31.57 31.57 32.07 32.07 32.07 31.57 TiO 2 0.00 7.50 0.00 2.50 0.00 2.50 2.50 WO 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Y 2 O 3 27.17 27.17 27.17 27.67 27.67 27.67 27.17 Property Abbe Number 53 46 49.3 (FU) Refractive Index 1.6402 1.6750 1.6620 1.6507 1.6454 (BA) CTE 53.1 49 40.2 48.3 50.9 47.2 45.7 (cm × 10 −7 /cm) Log 3 1189 1164 1179 1186 1173 1172 Temp (° C.) Liquidus Temp 1299 1222 1397 1213 1216 1232 1208 (° C.) ΔT (° C.) −110 −58 −34 −31 −59 −37 [0000] TABLE 7 Ex. 29 Ex. 30 Ex. 31 Ex. 32 Ex. 33 Ex. 34 Ex. 35 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 17.00 16.74 16.91 16.57 16.83 16.40 21.00 B 2 O 3 9.85 9.70 9.80 9.60 9.75 9.50 5.07 MgO + CaO + SrO + 0.00 0.00 0.00 0.00 0.00 0.00 0.00 BaO K 2 O 0.00 0.00 0.00 0.00 2.50 5.00 0.00 La 2 O 3 10.83 10.67 10.78 10.56 10.73 10.45 28.93 Li 2 O 1.50 3.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 2.00 4.00 0.00 0.00 0.00 Nb 2 O 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SiO 2 32.58 32.08 32.41 31.75 32.24 31.41 30.00 TiO 2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 WO 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Y 2 O 3 28.24 27.81 28.10 27.52 27.95 27.24 15.00 Property Abbe Number (FU) Refractive Index (BA) CTE 53.7 66.1 54.1 66.1 56.9 65.8 51.7 (cm × 10 −7 /cm) Log 3 1130 1081 1176 1164 1189 1184 1206 Temp (° C.) Liquidus Temp 1228 1251 1273 1300 1251 1288 1226 (° C.) ΔT (° C.) −98 −170 −97 −136 −61 −103 −20 [0000] TABLE 8 Ex. 36 Ex. 37 Ex. 38 Ex. 39 Ex. 40 Ex. 41 Ex. 42 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 16.95 16.64 16.32 20.07 19.13 18.20 19.00 B 2 O 3 9.69 9.38 9.06 6.30 7.54 8.77 6.00 MgO + CaO + 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SrO + BaO K 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 La 2 O 3 10.69 10.38 10.06 24.45 19.96 15.48 23.00 Li 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nb 2 O 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SiO 2 32.76 32.45 32.13 30.77 31.53 32.30 32.00 TiO 2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 WO 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Y 2 O 3 29.92 31.17 32.42 18.42 21.84 25.26 20.00 Property Abbe Number (FU) Refractive Index 1.6535 (BA) CTE 50.8 49.4 49.7 51.4 49.3 48.2 (cm × 10 −7 /cm) Log 3 1199 1178 1179 1201 1184 1196 1200 Temp (° C.) Liquidus Temp 1213 1258 1218 1204 1199 1169 1246 (° C.) ΔT (° C.) −14 −80 −39 −3 −16 27 −46 [0000] TABLE 9 Ex. 43 Ex. 44 Ex. 45 Ex. 46 Ex. 47 Ex. 48 Ex. 49 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 19.37 19.00 19.49 19.00 19.39 19.00 19.41 B 2 O 3 6.36 6.00 6.36 6.00 6.14 7.00 6.99 MgO + CaO + 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SrO + BaO K 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 La 2 O 3 23.26 24.00 23.71 26.00 25.31 23.00 23.30 Li 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nb 2 O 5 0.17 1.50 1.07 0.00 0.11 0.00 0.24 SiO 2 31.54 32.00 31.71 32.00 31.69 31.50 31.36 TiO 2 0.11 0.00 0.19 0.00 0.16 1.50 1.04 WO 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Y 2 O 3 19.19 17.50 17.47 17.00 17.20 18.00 17.65 Property Abbe Number 54.08 (FU) Refractive 1.6529 1.6533 1.6533 1.6523 1.652 1.657 1.6553 Index (BA) CTE 44.0 (cm × 10 −7 /cm) Log 3 1189 1201 1195 1201 1202 1184 1190 Temp (° C.) Liquidus Temp 1209 1210 1229 1201 1212 1205 1174 (° C.) ΔT (° C.) −20 −9 −34 0 −10 −21 16 [0000] TABLE 10 Ex. 50 Ex. 51 Ex. 52 Ex. 53 Ex. 54 Ex. 55 Ex. 56 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 19.00 19.42 19.00 19.37 19.00 19.38 20.50 B 2 O 3 7.50 7.40 8.00 7.65 8.00 7.62 8.00 MgO + CaO + 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SrO + BaO K 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 La 2 O 3 25.00 24.61 23.00 23.21 23.00 23.33 23.00 Li 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nb 2 O 5 0.00 0.27 0.00 0.15 1.50 1.21 0.00 SiO 2 30.50 30.48 30.00 30.21 30.50 30.49 30.00 TiO 2 0.00 0.23 0.00 0.18 0.00 0.24 1.50 WO 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Y 2 O 3 18.00 17.61 20.00 19.23 18.00 17.73 17.00 Property Abbe Number (FU) Refractive 1.6517 1.6534 1.6531 1.6532 1.6527 1.6515 1.6529 Index (BA) CTE (cm × 10 −7 /cm) Log 3 1190 1186 1179 1181 1183 1178 1180 Temp (° C.) Liquidus Temp 1207 1203 1178 1212 1216 1184 1276 (° C.) ΔT (° C.) −17 −17 1 −31 −33 −7 −96 [0000] TABLE 11 Ex. 57 Ex. 58 Ex. 59 Ex. 60 Ex. 61 Ex. 62 Ex. 63 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 20.32 21.00 21.09 21.00 20.98 21.00 20.85 B 2 O 3 7.56 5.00 5.48 6.00 6.15 7.00 6.91 MgO + CaO + 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SrO + BaO K 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 La 2 O 3 23.35 23.00 23.23 24.50 24.04 23.00 23.20 Li 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nb 2 O 5 0.24 0.50 0.43 0.00 0.24 2.00 1.28 SiO 2 30.27 32.00 31.73 31.00 31.05 30.00 30.42 TiO 2 0.99 0.00 0.19 0.50 0.31 0.00 0.12 WO 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Y 2 O 3 17.27 18.50 17.85 17.00 17.24 17.00 17.20 Property Abbe Number (FU) Refractive 1.6556 1.6541 1.6528 1.6525 1.6506 1.6551 1.6535 Index (BA) CTE (cm × 10 −7 /cm) Log 3 1187 1215 1212 1200 1204 1182 1199 Temp (° C.) Liquidus Temp 1252 1291 1280 1272 1268 1277 1272 (° C.) ΔT (° C.) −65 −76 −68 −71 −64 −95 −73 [0000] TABLE 12 Ex. 64 Ex. 65 Ex. 66 Ex. 67 Ex. 68 Ex. 69 Ex. 70 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 21.50 21.06 20.64 20.08 18.46 17.46 16.46 B 2 O 3 6.50 6.67 6.74 6.72 6.99 6.99 6.99 MgO + CaO + 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SrO + BaO K 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 La 2 O 3 23.00 23.23 23.32 23.69 23.30 23.30 23.30 Li 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nb 2 O 5 0.00 0.16 0.63 0.51 0.24 0.24 0.24 SiO 2 30.00 30.38 30.65 30.99 31.36 31.36 31.36 TiO 2 0.00 0.15 0.33 0.36 2.00 3.00 4.00 WO 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Y 2 O 3 19.00 18.35 17.68 17.65 17.65 17.65 17.65 Property Abbe Number (FU) Refractive 1.6532 1.6520 1.6526 1.6531 1.6562 1.662 1.6697 Index (BA) CTE (cm × 10 −7 /cm) Log 3 1194 1200 1188 1189 1181 1172 1163 Temp (° C.) Liquidus Temp 1283 1261 1256 1245 1188 1141 1133 (° C.) ΔT (° C.) −89 −61 −68 −56 −7 31 30 [0000] TABLE 13 Ex. 71 Ex. 72 Ex. 73 Ex. 74 Ex. 75 Ex. 76 Ex. 77 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt.) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 15.46 19.41 19.41 19.41 19.41 19.41 19.41 B 2 O 3 6.99 6.03 5.03 4.03 3.03 6.99 6.99 MgO + CaO + 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SrO + BaO K 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 La 2 O 3 23.30 23.30 23.30 23.30 23.30 23.30 23.30 Li 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nb 2 O 5 0.24 0.24 0.24 0.24 0.24 0.24 0.24 SiO 2 31.36 31.36 31.36 31.36 31.36 30.40 29.40 TiO 2 5.00 2.00 3.00 4.00 5.00 2.00 3.00 WO 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Y 2 O 3 17.65 17.65 17.65 17.65 17.65 17.65 17.65 Property Abbe Number (FU) Refractive 1.6754 1.6597 1.668 1.6774 1.6857 1.6605 1.6688 Index (BA) CTE (cm × 10 −7 /cm) Log 3 1152 1179 1180 1183 1183 1164 1158 Temp (° C.) Liquidus Temp 1181 1234 1249 1261 1272 1217 1231 (° C.) ΔT (° C.) −29 −56 −69 −78 −88 −53 −72 [0000] TABLE 14 Ex. 78 Ex. 79 Ex. 80 Ex. 81 Ex. 82 Ex. 83 Ex. 84 (% by (% by (% by (% by (% by (% by (% by wt.) wt.) wt.) wt.) wt.) wt.) wt.) Chemical Al 2 O 3 19.41 19.41 19.25 18.76 18.26 17.77 17.52 B 2 O 3 6.99 6.99 6.92 6.92 6.92 6.92 7.20 MgO + CaO + 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SrO + BaO K 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 La 2 O 3 23.30 23.30 23.06 23.06 23.06 23.06 23.28 Li 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Na 2 O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nb 2 O 5 0.24 0.24 0.24 0.24 0.24 0.24 0.00 SiO 2 28.40 27.40 31.08 30.58 30.09 29.59 31.58 TiO 2 4.00 5.00 1.98 2.97 3.96 4.95 2.82 WO 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Y 2 O 3 17.65 17.65 17.47 17.47 17.47 17.47 17.61 Property Abbe Number (FU) Refractive 1.677 1.686 1.6566 1.6634 1.6718 1.6792 1.6560 Index (BA) CTE (cm × 10 −7 /cm) Log 3 1142 1135 1166 1164 1157 1146 1181 Temp (° C.) Liquidus Temp 1234 1249 1217 1209 1187 1179 1104 (° C.) ΔT (° C.) −92 −113 −51 −45 −29 −33 77 [0000] TABLE 15 Ex. 85 Ex. 86 (% by (% by wt.) wt.) Chemical Al 2 O 3 17.23 17.42 B 2 O 3 7.26 6.86 MgO + CaO + 0.00 0.00 SrO + BaO K 2 O 0.00 0.00 La 2 O 3 23.34 23.42 Li 2 O 0.00 0.00 Na 2 O 0.00 0.00 Nb 2 O 5 0.00 0.00 SiO 2 31.69 31.25 TiO 2 2.84 3.27 WO 3 0.00 0.00 Y 2 O 3 17.65 17.78 Property Abbe Number (FU) Refractive 1.6597 1.6633 Index (BA) CTE (cm × 10 −7 /cm) Log 3 1178 1172 Temp (° C.) Liquidus Temp 1163 1148 (° C.) ΔT (° C.) 15 24 [0031] Looking at Tables 3-15, it can be concluded that the glass compositions of Examples 1-86 have a very high refractive index in comparison with commercially available continuous fiber products (e.g., the refractive index for S2 glass is 1.52, E-glass is about 1.58 to 1.62 and ECR glass is 1.58) with forming temperatures and ΔT values that allow these glasses to be manufactured by known platinum-lined furnace melting techniques. [0032] The invention of this application has been described above both generically and with regard to specific embodiments. Although the invention has been set forth in what is believed to be the preferred embodiments, a wide variety of alternatives known to those of skill in the art can be selected within the generic disclosure. The invention is not otherwise limited, except for the recitation of the claims set forth below.

A glass composition including SiO 2 in an amount from 30.0 to 40.0% by weight, Al 2 O 3 in an amount from 15.0 to 23.0% by weight, B 2 O 3 in an amount from 0.0 to 15.0% by weight, K 2 O in an amount from 0.0 to 5.0% by weight, La 2 O 3 in an amount from 0.0 to 30.0% by weight, Li 2 O in an amount from 0.0 to 3.0% by weight, Na 2 O in an amount from 0.0 to 4.0% by weight, Nb 2 O 5 in an amount from 0.0 to 10.0% by weight, TiO 2 in an amount from 0.0 to 7.5% by weight, WO 3 in an amount from 0.0 to 10.0% by weight, Y 2 O 3 in an amount from 15.0 to 35.0% by weight, and RO (one or more of MgO, CaO, SrO, and BaO) in an amount from 0.0 to 7.5% by weight is provided. Glass fibers formed from the composition have a refractive index between 1.55 and 1.69.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a 371 of international patent application number PCT/EP2012/050617 filed Jan. 17, 2012, having the same inventor and the same title, and which is incorporated herein by reference in its entirety, which application claims the benefit of U.S. provisional application No. 61/433,621, filed Jan. 18, 2011, having the same inventor and the same title, and which is incorporated herein by reference in its entirety. FIELD OF THE DISCLOSURE [0002] The present disclosure relates generally to communications platforms, and more particularly to systems and methods for collaboration over open platforms. BACKGROUND OF THE DISCLOSURE [0003] Various commercial endeavors require the collaboration of diverse parties with diverse skill sets to bring the endeavor to fruition. Frequently, it is necessary for these parties to exchange data, to obtain access to data generated as part of the endeavor, or to manipulate the data in order to create useful information. These tasks are frequently complicated by the fact that the parties collaborating on the project may be working from geographically disperse locations, and are often business competitors of each other. [0004] For example, in the operation of an oil rig during oil or natural gas exploration, a variety of data is generated concerning the condition or status of the well, rig, drilling equipment, drilling operations, and various supplies and resources. This data will typically be generated by the party responsible for a particular task. Data will also be created in the form of alerts generated by monitoring equipment, which are issued from time to time to notify interested parties of potential problems with the well, the rig or the drilling equipment. All of this data must be processed into information so that appropriate action may be taken at each point in time by the appropriate parties, and the information so generated must typically be monitored by the exploration company. BRIEF DESCRIPTION OF THE DRAWINGS [0005] FIG. 1 is an illustration of a system architecture over which the systems and methodologies described herein may be implemented. [0006] FIG. 2 is an illustration of a first embodiment of a system in accordance with the teachings herein. [0007] FIG. 3 is an illustration of a second embodiment of a system in accordance with the teachings herein. [0008] FIG. 4 is an illustration of the functionality of one particular, non-limiting embodiment of a system in accordance with the teachings herein. SUMMARY OF THE DISCLOSURE [0009] In one aspect, a platform is provided which facilitates collaboration among a plurality of users on a project (such as the exploration for oil or natural gas on an oil rig), data set and/or data stream. The platform comprises (a) a data hub configured to allow a plurality of users to store data on the data hub and to retrieve data from the data hub; (b) an interface associated with the data hub which is independently configurable by each of said plurality of users, wherein each user has a set of user preferences associated with that user which controls the configuration of the interface when it is accessed by that user; (c) a plurality of data files stored on said hub, wherein each of said data files is associated with one of said plurality of users and is accessible via the interface; and (d) a security system which authenticates a user and which restricts access of the data files to those data files associated with the user. [0010] In another aspect, a method is provided for obtaining services from third parties. The method comprises (a) providing a platform (preferably of the type described above) associated with a company and upon which third party service providers can register to receive notices of service requests; (b) posting service requests to the platform, wherein each service request contains a description of the service required; and (c) receiving bids from the third party service providers in response to the posted service requests. [0011] In a further aspect, a method is provided for facilitating collaboration among parties working on a project, data set, and/or data stream, wherein the collaboration involves the generation or manipulation of data by one or more of the parties. The method comprises (a) providing a platform of the type described above; (b) storing the data on the data hub in a plurality of data files; (c) associating a particular data file with a particular set of users; (d) restricting access to each of the plurality of data files to those users associated with the data file; and (e) allowing a user to manipulate data in the hub, including, but not limited to, by the use of external software loaded onto the hub. [0012] In still another aspect, a method is provided by which an entity can offer goods or services to other parties. The method comprises (a) providing a platform associated with the entity and upon which parties can register to post requests for goods or services from the entity; (b) receiving the requests at the platform, wherein each request contains a description of the goods or services required; and (c) posting bids to the platform from the entity in response to the posted requests. [0013] In yet another aspect, a non-transitory computer readable medium is provided which contains programming instructions, the execution of which, by one or more processors of a computer system, causes the one or more processors to carry out the foregoing methods or to establish the foregoing systems. DETAILED DESCRIPTION [0014] A variety of solutions have emerged in the marketplace to deal with the enormous amount of data and information generated during oil and natural gas exploration and other such collaborative endeavors. However, the real time operations (RTO) solutions which have been developed to date suffer from a number of infirmities which adversely affect the ability of parties to collaborate on the underlying project. [0015] At present, RTO solutions are typically implemented as proprietary systems. Thus, most RTO systems in the oil and gas industry are derived from the down-hole data acquisition systems associated with the service company, where proprietary information of their latest technology is utilized. Each service company has its own implementation methods. Recent advances in hardware and software designs allow independent RTO service providers to build their own systems. However, by design, these systems function as a data aggregation service only, and do not provide software as a service (SaaS). [0016] Conventional RTO solutions are also typically configured to provide only passive participation from data sources. In order to protect the proprietary technology implemented by the solution, conventional RTO systems do not allow other parties to control and configure the system. Hence, these systems expect data sources to stream data using industry standard protocols such as WITS and/or WITSML based on predefined or agreed sequences or lists. If there is a new requirement or a change in data type, both parties to a data exchange must typically repeat the cycle in order to ensure that the data being sent and received matches. The major drawback in this scenario is that the data source cannot directly participate to perform in-system data quality control (QC) or to create event/incident entries. Moreover, at present, event recording is typically part of a 12-hour batch reporting practice, which is already after-the-fact instead of real time. [0017] Conventional RTO solutions also typically require a specialist to run the system. In particular, the system must be operated either by the system vendor, by trained customer IT personnel, or by an engineer associated with a 3rd party reseller. [0018] In addition, conventional RTO solutions suffer from an unstructured or oversimplified data ownership structure. In particular, while current RTO systems have proper system authentication and authorization to own and access the data, the security is provided only at the system level. Hence, there is no data level security protection built in. [0019] Finally, current solutions suffer from manual and rigid data control processing. In particular, data integrity checks must be performed manually by an RTO engineer who is typically the system administrator. This situation arises in part from the lack of a clear data ownership structure implemented in the system. [0020] It has now been found that some or all of the foregoing needs may be addressed by the systems and methodologies disclosed herein. These systems and methodologies may be utilized to create an open platform for mobile collaboration which is preferably powered by open source software, and which is preferably enabled by Web 2.0 solutions. This platform may be used to establish a secure solutions marketplace (SSM) along with a real time virtual work space (RVWS). The SSM is secure in that it preferably follows industry standard best practices in protecting data confidentiality and integrity. Typically, this is accomplished through the proper use of authentication to access the system interface, and by requiring that a party have appropriate authorization to access data and system resources. [0021] The systems and methodologies disclosed herein may cover all products and their associated value-added services which are utilized to transform data into information for decision making purposes. These systems and methodologies may include data visualization, data mining, data processing, data interpretation, and data transformation. In a preferred embodiment, the platforms described herein will be openly configurable and accessible to all parties involved with a collaborative endeavor. Thus, for example, in the case of oil and natural gas exploration, the platform may be openly configurable and accessible to oil and natural gas companies or operators, rig companies or drilling contractors, service companies, independent consultants or subject matter experts, and regulatory bodies (including local governments). [0022] For purposes of illustration, the systems and methodologies described herein will frequently be illustrated and explained with respect to their implementation in the oil and natural gas exploration field, since many embodiments of these systems and methodologies are particularly advantageous in facilitating the collaboration required from diverse parties in this field. It will be appreciated, however, that these systems and methodologies are broadly applicable in a variety of fields, especially in applications requiring extensive collaboration between parties, and hence are not limited to the field of oil and gas exploration. [0023] FIG. 1 depicts first 101 , second 103 and third 105 particular, non-limiting embodiments of system architectures over which the systems and methodologies disclosed herein may be implemented. For purposes of illustration, these embodiments are described specifically with respect to their implementation in oil and natural gas exploration. However, it will be appreciated that each of these embodiments is applicable to any type of collaborative effort utilizing the disclosed communications infrastructures. In each of these architectures, a data hub 119 is maintained at a first location (a rig site 111 ) and is replicated at a second location (a third party site 117 ), but the network 112 over which communications occur is different in each instance. [0024] In the first embodiment 101 , the customer 113 (typically an oil and natural gas exploration company) has its own network, and communications between the customer 113 and the rig site 111 (and its associated data hub 119 ) occur via an enterprise service gateway (ESG) 121 (also known as an intranet bridge). The ESG 121 in this embodiment will typically reside behind a corporate firewall 123 . If a contractor or other third party 117 is required to obtain access to data, they do so through the Internet 115 or (other public communications network) and the company's firewall 123 to connect to the ESG 121 . [0025] In the second embodiment, the customer 113 maintains a site on a public communications network such as the Internet 115 , and communications between the customer 113 and the rig 111 occur via an Internet Service Gateway (ISG) 127 (also known as an Internet Bridge). The ISG 127 in this embodiment will typically be associated with an Internet proxy server 125 , and the customer 113 provides Internet connectivity for third parties 117 to send data to the ISG 127 from the third party's data hub 120 . [0026] In the third embodiment 105 , the customer does not maintain a network independent of the data hub 119 on the rig 111 . In this embodiment, communications occur in a point-to-point manner between the data hub 119 on the rig 111 , a data hub 120 associated with a third party 117 , and the associated users at 129 who may be working from various locations. Hence, in this embodiment, a contractor or other third party 117 may have employees on the rig 111 collecting data, and if they wish to send data from the rig 111 to another site, they will have to use the data hub 119 on the rig 111 and a third party data hub 120 (which may be their own data hub or the data hub of another third party) to establish an ad hoc point-to-point connection. Hence, the data in the data hub 119 at the rig site will be exactly the same as the data in the data hub 120 at the corporate office of the customer. In other words, the data from the data hub 119 at the rig site is simply replicated at the customer's data hub 120 . [0027] FIG. 2 illustrates a particular, non-limiting embodiment of a platform which may be utilized to implement some of the methodologies disclosed herein. In the embodiment of FIG. 2 , the platform 201 comprises a data hub 203 which acts as a data logger, and which is equipped with a data interface 205 . The data interface 205 in this particular embodiment is equipped with a variety of connections, including a TCP/IP connection 207 , an RS232 serial cable 209 , and an RS485 cable 211 (a serial cable with a special connection for connecting the data hub to a control system). All three of these connections implement standard industry protocols, and most modern computer equipment has interfaces for all three. [0028] The data hub 203 is adapted to collect data from service companies at the rig site using common data transfer protocols. Many service companies will use the WITSML (Wellsite Information Transfer Standard Markup Language) protocol or the older WITS (Wellsite Information Transfer Specification) protocol for data exchange. [0029] The data hub 203 also collects data from PLCs (programmable logic controllers, which are digital computers used for automation of electromechanical processes) and smart sensors 213 . A protocol known as ModBus, which is a serial communications protocol for PLCs, may be utilized for this purpose. ModBus allows for communication between many devices connected to the same network. By way of example, ModBus may be utilized by a system that measures temperature and humidity to communicate the results to a computer. The rig site automation control system is typically controlled by a PLC system which communicates with a control center via a MODBUS protocol. [0030] ModBus is also preferably used in the platform 201 as the protocol for communications between supervisory computers and remote terminal units (RTUs) in SCADA (Supervisory Control and Data Acquisition) systems 214 associated with the platform 201 . While protocols such as WITSML are commonly used for the exchange of information between a control center and a rig, SCADA protocols are the current industry standard used in oil and gas rigs for monitoring and control systems. Hence, SCADA systems typically collect data and send it to a remote control center, and receive commands from the control center which allow the control center to control system components such as valves and pumps. Thus, by way of example, SCADA systems allow a control center to monitor how much oil and gas is being produced at a rig, and to increase or decrease production by sending appropriate control signals. In contrast to SCADA, which is utilized in systems having both monitoring and control functionalities, WITSML and WITS are purely information exchange protocols (i.e., they provide only a monitoring functionality). [0031] In a typical implementation, the SCADA system 214 may consist of the following subsystems: (a) A Human-Machine Interface (HMI). This is the apparatus which presents process data to a human operator, and through which the human operator monitors and controls a process. (b) A supervisory (computer) system, which gathers or acquires data on the process and sends commands or controls to the process. (c) Remote Terminal Units (RTUs). These units connect to sensors in the process, convert sensor signals to digital data, and send the digital data to the supervisory system. (d) PLCs. These devices are used as field devices because they are more economical, versatile, flexible, and configurable than special-purpose RTUs. (e) Communication infrastructure which connects the supervisory system to the RTUs. [0037] The data being generated at the rig site is received and aggregated by the data hub 203 into a database 215 . Depending on the system architecture (see FIG. 1 ), a TCP/IP connection 217 connects the data hub 203 to either a service gateway ( 121 in FIG. 1 ) or to a second data hub ( 120 in FIG. 1 ) to replicate the data that has been collected by the data hub 203 . The TCP/IP connection 217 preferably utilizes secure tunneling (which may be implemented as secure shell (SSH) tunneling or a virtual private network (VPN)) for file synchronization, database synchronization and real-time (RT) streaming. Such secure tunneling may be implemented with the Hypertext Transfer Protocol (HTTP) or Hypertext Transfer Protocol Secure (HTTPS), the latter of which is a combination of HTTP with the secure sockets layer/transport layer security (SSL/TLS) protocol. [0038] Database synchronization is preferably implemented using JavaScript object notation (JSON), a lightweight text-based open standard designed for human-readable data interchange. RT streaming is preferably implemented using asynchronous JavaScript and XML push (AJAX Push), a web application model in which a long-held HTTP request allows a web server to push data to a browser without the browser explicitly requesting it. [0039] The TCP/IP connection 217 to the data hub 203 is preferably secured with a firewall 233 . The firewall 233 is preferably equipped with security certificate finger printing, which preferably utilizes public-key cryptography standards (PKCS) and personal identification numbers (PINs) or other universally unique identifiers (UUIDs) for zero-configuration transparent connectivity service. [0040] Conventional systems for exchanging data between a rig and a control center have an input and an output, and replicate data from the rig site to the control center. By contrast, in the system depicted in FIG. 2 , the data hub 203 is equipped with a full web interface 219 so that any party will be able to operate the data hub 203 and will be able to control and configure the web interface 219 . This web interface 219 provides for the exchange of files 221 , such as pictures and reports, and further provides for the import or export of data in various file formats, such as ASCII (American Standard Code for Information Interchange), LAS (Log ASCII Standard), LIS (Log Information Standard), DLIS (Digital Log Interchange Standard) and XML (Extensible Markup Language) formats. Voice 223 , video 225 and chat 227 functionalities are also preferably supported. [0041] As a result of the web interface 219 , the data hub 203 operates like an independent, stand-alone server which allows any interested party to connect to and access it with web browser software. Consequently, there is no need to download any software—rather, a party only needs to input the web address to gain access to the data hub 203 . After that, the party can configure the data hub 203 with personalized settings as the party sees fit, and the configuration does not require any kind of specialized knowledge (an analogy may be made here to a user's homepage on the FACEBOOK™ social network, in that the homepage does not require that the user have any kind of specialized knowledge in order to use or configure it). [0042] The advantages of the system of FIG. 2 may be more fully appreciated by considering conventional systems used in the oil and gas industry to collect data at a rig. In such systems, the data hub is typically proprietary, and can only be configured by the service provider that is providing the database. Hence, when service companies are providing services at a rig, an expert is typically required to configure the data hub. By contrast, a system of the type depicted in FIG. 2 reduces operating costs by eliminating the need for such an expert. [0043] Moreover, in a typical exploration operation in the oil and gas industry, the operator has to employ service companies in order to drill a well. In particular, the operator typically does not own the drilling rig, but contracts a drilling company to drill the well. During drilling operations, there may be 10 to 15 different service companies operating on the rig, some of which may be in competition with each other. Typically, all of the service companies are generating data of one type or another, and all of the data needs to be available to the operator for monitoring purposes. [0044] Also, in a conventional operation, the communications platform containing the data hub will be owned and operated by one of the service companies, and hence, that company will have to allow the other service companies—some of whom are their competitors—to have access to the data hub. However, service companies are typically reluctant to allow their competitors (the other service companies) to configure their data hubs. Hence, the service company will typically have an engineer available to maintain the data hub, get the data stream from all of the service companies, and send it to the operator so that the operator can monitor the data. [0045] By contrast, the system depicted in FIG. 2 provides an open web interface 219 so that each service company can configure its own data without the need to involve an expert. In particular, the open web interface 219 allows each service company to configure the web interface 219 . However, the data entered into the data hub 203 will ultimately be input in the same format. Each service provider is thus able to establish its own access to its own data, and is able to configure the web interface 219 as it sees fit. Moreover, access to the data of a service provider may be secured with a user ID and password by way of an authentication and authorization system 231 , which may utilize pluggable authentication modules (PAM). [0046] A further advantage of the system of FIG. 2 over conventional systems in the art relates to data security. Conventional communications platforms utilized in the art are equipped with system-based data security. Hence, once a party has access to the system, that party can see all of the data. In such a system, the service companies do not have access to the data hub, and the data hub is proprietary to a particular company. By contrast, in the system of FIG. 2 , all parties of interest will have access to the data hub 203 . However, in order to prevent these parties from being able to see each other's data, security may be provided at both the system level and the data level. Therefore, while all of the parties of interest will have access to the data hub 203 , they will not be able to see each other's data within the data hub 203 . [0047] A further issue faced with conventional systems in the art relates to the operation of software on the data in the data hub. Typically, the data coming into the data hub is useful only after it is processed into information, and hence, a data hub requires applications to process the data contained in the data hub. For example, graphics software may be utilized to visualize the data, and data mining software may be utilized, for example, to perform statistical analyses on the data. It may also be necessary to perform data processing on the data to remove errors or anomalies from the data, to interpret the data, or to perform other such functions. Since data hubs in conventional systems are typically proprietary, the software which processes the incoming data is also a proprietary. This often limits the customer/operator to using specific service providers. Moreover, the data hub itself is typically capable of running few, if any, applications, due to processing power limitations. [0048] FIG. 3 depicts a second particular, non-limiting embodiment of a platform in accordance with the teachings herein. The platform 301 of FIG. 3 overcomes the foregoing infirmity through the provision of a service gateway 334 which is adapted to run the applications used to process data resident in a data hub 315 . [0049] In the system of FIG. 3 , the data hub 315 collects all of the incoming data. The data hub 315 further provides access to a particular service party to the data input by that service party, thus allowing the service party to configure its data stream. The system 301 provides security at the data level, so that the data corresponding to each service party is not accessible to any other party without permission. Hence, the data hub 315 collects the data and configures it correctly, and the security is built in. [0050] As with the previous embodiment, the embodiment of FIG. 3 is equipped with an open web interface 319 which is configurable by each service company, which allows each service company to configure its own data without the need to involve an expert, which allows each service company to establish its own access to its own data, and which provides voice 323 , video 325 and chat 327 functionalities and for the exchange of files 321 as described with respect to the previous embodiment. Also as with the previous embodiment, the embodiment of FIG. 3 is equipped with an authentication and authorization system 331 which may utilize pluggable authentication modules (PAM) and which allows access to the data of a service provider to be secured with a user ID and password. [0051] The system 301 of FIG. 3 is provided with a TCP/IP connection 317 , and the data hub 315 is accessible either through an ESG (within the corporate security firewall) or an ISG (over the Internet). The data hub 315 collects data and replicates it into the service gateway 334 . [0052] One usage for the data hubs described herein relates to the processing of alerts. Currently, some oil companies utilize a so-called real time center (RTC) to monitor the mud level in several different oil wells. The mud pit level may change for several different reasons. Typically, this will trigger an alert, and the person in the RTC (in town) will call the rig crew to find out why the mud pit level changed. If there is a reason for the mud pit level change, an explanation will be provided by someone at the rig, and the alert will be closed. Alerts are classified is red, yellow and green. If a given alert cannot be explained, it may be escalated to a yellow alert. [0053] Typically, the crew on the rig knows the reason for the alert, because they are generating the data which gives rise to it. However, in conventional systems, the personnel with the expertise on the rig to dispense with an alert typically do not have access to the data hub due to its proprietary nature. On the other hand, the person monitoring the alerts in the RTC typically does not know the underlying facts giving rise to an alert. Hence, it is common in the operation of an oil rig for the people in the RTC to have to make numerous calls to the rig simply to find out what is happening. Since approximately 90% of all alerts generated on a typical rig are false in the sense that they do not pertain to a real underlying problem, most of these communications from the RTC to the rig are ultimately unnecessary. [0054] On the other hand, the person in the RTC must be able to respond appropriately to alerts when they are real, and hence must have a significant amount of training and experience (typically at least 20 years). Due to the high incidence of spurious alerts, this person spends much of his time calling the rigs under his supervision just to find out what is happening. Consequently, the person in the RTC can typically monitor no more than three rigs at a time (this number is based on best practices in several oil companies today). [0055] By contrast, in the systems described herein, the crew on the rig will preferably have direct access to the data hub 315 . Hence, the party responsible for monitoring the mud system will see the alert first and can close it down if it is spurious, because he has access to the system. Hence, the systems described herein may achieve significant reductions in overhead (in terms of manpower), because the frequency at which calls must be placed from the RTC to the rig is significantly reduced. Also, the system may be equipped with an e-mail service 341 and an alarm service 343 which is in communication with a beeper or other means for notifying a party responsible for a system or event with respect to which an alert is being generated so that, when an alert is generated, the person responsible for the area to which it pertains will be notified. The systems described herein allow many problems to be disposed of on the rig, because there are personnel on the rig with expertise to dispose of the problem. [0056] It will be appreciated from the foregoing that the systems disclosed herein allow people associated with a project to collaborate more effectively because they have access to the data hub 315 . These systems thus avoid many communications of the type that are necessitated in conventional systems simply by the fact that information is missing or unavailable. In a system 301 of the type depicted in FIG. 3 , the person in the RTC may now merely police the alert system and efficiently focus his expertise to provide more value and better service to his customer. Hence, he will still be notified of alerts, but is no longer required to respond in every case. [0057] Referring again to the system of FIG. 3 , the service gateway 333 is preferably programmed with open source code, and is adapted to have software installed on it. This feature, denoted as an applications service 345 , allows for greater collaboration by experts around the world, because an expert can load his software into the gateway 333 , use it to manipulate data in the hub 315 , and then share that data and information generated from it with other parties. By contrast, the proprietary systems currently in use do not provide a means by which other parties may readily install their software on a service gateway. Instead, in such systems, it is typically necessary for such parties to have the data transferred to their own computer. Hence, the information these parties produce by processing the data in such systems is an isolated product and isolated work. [0058] By contrast, in the systems described herein, the work product generated by a party may be used by anyone, so long as they have authorization to use the software. Hence, these systems enable “software as a service” (SaaS). For example, these systems allow a software producer to simply charge an end user for using the software, rather than selling the software to the end user outright (that is, the software producer can essentially sell time on the software). [0059] An end user may also be given permission to upload software to the service gateway 333 over the web. By having the SaaS feature, the system 301 allows usable information to be extracted from the data in the data hub 315 without physically moving sensitive data out of the system. This may be particularly useful in applications where movement of data is either not permitted, or is closely regulated. For example, government agencies in countries such as Indonesia do not allow down-hole information to leave the country, making this feature particularly useful in oil and natural gas exploration applications there. [0060] A further advantage of the systems and methodologies disclosed herein relates to their ability to act as an expert geo-location service 351 . Since the platform is preferably open by way of a web service 355 , anyone working in the industry can register themselves to it. Hence, the platform facilitates the creation of a directory 353 of all of the people that are registered in the system (a “directory of experts”). Preferably, this directory 353 is implemented with the lightweight directory access protocol (LDAP), an application protocol for accessing and maintaining distributed directory information services over an Internet protocol (IP) network. [0061] Currently, oil and gas exploration companies spend significant resources trying to find people with the expertise that they require. However, the systems and methodologies disclosed herein allow anyone to register with the platform and note their areas of expertise, and hence, the platform acts as a marketplace for people wishing to sell their expertise, and provides a means by which the customer may identify potential experts for future work. These experts can also use the applications on the service gateway 333 to look at the customer's data for the purpose of bidding on a job, assessing their fit for a job, or as part of providing a combination of software and their expertise as a service. Currently in the industry, this type of platform does not exist, so collaboration is difficult. [0062] Such collaboration may be further facilitated in the systems and methodologies by the provision of suitable support services. As indicated in the embodiment of FIG. 3 , such support services may include voice chat services 361 , video conferencing services 363 , voice over IP (VOIP) services 365 , and the like. A TCP/IP connection 318 and a suitable firewall 334 may be provided to support these services. [0063] FIG. 4 summarizes the components of both the data hub 315 and the service gateway 333 for the system of FIG. 3 . All of these components are preferably web enabled, which means that they can be accessed using a platform independent web browser. [0064] While the systems and methodologies described herein have many advantageous features, two features described herein are especially conducive to the use of some embodiments of the platforms described herein in collaborative efforts. These are (a) a data ownership model in which the user has the capability to control the sharing of data directly or indirectly, and in which a data custodian role is introduced to facilitate this; and (b) a data hierarchy structure that acts as label tag to the user data to help connect a user to the correct target experts, and vice versa. [0065] While the systems and methodologies disclosed herein have been described above primarily in reference to their implementation in oil and natural gas exploration, one skilled in the art will appreciate that these systems and methodologies may be applied in a variety of other fields as well, and are potentially useful in any situation where a real time data stream is available. [0066] For example, these systems and methodologies may be adopted for business or consumer usage in various applications, such as equipment monitoring systems in which the usage of feedstocks (such as, for example, coolant, fluids, fuel or other feedstocks necessary for operation of the equipment) is monitored. In such an application, when supplies of a certain feedstock are running low, the system can make that information available to third parties and can, for example, locate the party willing to supply that feedstock at the lowest price. [0067] As a further example, the systems and methodologies disclosed herein may be adapted to monitor components of an automobile and to notify the owner when maintenance is required. Hence, instead of basing vehicle maintenance on an artificial and inefficient maintenance schedule (such as every 5000 miles), an automobile may be monitored in real time by a control room, and the owner may be notified when service is required. As part of this service, when service is required, an appointment may be set up automatically at a nearby dealership or auto repair shop. Also, the system may make the service information available so that third parties are able to bid on any services that are required. It will be appreciated that this application may find use by individual vehicle users or owners (such as, for example, individual consumers), or by businesses that need to maintain a fleet of vehicles. [0068] Similarly, trucking companies may use the systems and methodologies disclosed herein to monitor the maintenance status and location of their trucks. In these applications, the system may act as a resource and scheduling management system. [0069] The systems and methodologies disclosed herein may also be utilized in retail inventory management, especially for small retailers. This may be achieved, for example, by connecting a black box (data hub) to the cash registers of a retail business. In this way, retail sales transactions may be uploaded on a real time basis to a service gateway on the cloud. This could open up a few possibilities. [0070] For example, retailers may want an inventory control mechanism. A cloud based service gateway of the type described herein may be utilized to manage the inventory for a particular retailer. Such a system may generate an automatic replenishment order to maintain a certain level of inventory based on real time sales information, may adjust prices based on sales trends in real time, and may take other suitable actions to allow the retailers to act on information promptly. Additionally, chain retailers could use the system to make stock information available to consumers in real time, for example, the store location(s) in which a given product is available at that time. [0071] The systems and methodologies described herein may also be utilized to allow retailers to form networks and use their collective bargaining power to get better deals from suppliers. This may allow shops which are individually owned by small shop keepers to combine their purchasing power for the purpose of securing more advantageous terms from suppliers. [0072] The systems and methodologies described herein may also be utilized by merchants to identify suitable experts required to address their business needs. For example, once merchants have their sales and inventory information online, they may be able to seek services from business experts to help them optimize their business models. [0073] Assuming they are willing to share part of their real time sales data, manufacturers and suppliers may leverage the systems and methodologies described herein to obtain sales intelligence in different locations of the world. In particular, manufacturers and suppliers may use such real time sales information for business planning purposes. [0074] The systems and methodologies described herein may also be utilized to perform real time, condition based monitoring in the automotive industry. For example, a user may install data hubs on all vehicles the user wishes to monitor. The data hubs may be used to collect RT data from sensors, and to send this data to a service gateway. On the service gateway, the user may be able to opt to share particular information, or to use an SaaS application to transform the data (for example, such an application may be utilized to transform recorded GPS coordinates to distance traveled and engine hours) and to share this new information with several preferred service providers. Service providers may then monitor the information manually, or may use a SaaS application to generate suitable alarms to provide a quote for services (competitive bidding). The user may then select a service provider based on the quote for services, the proximity of the service provider, and the timing required to procure a maintenance service. [0075] It will be appreciated that the concepts underlying the foregoing example may be readily adapted to other industries as well. These concepts may be applied, for example, to the monitoring used in power plants, mining sites, manufacturing plants and prime movers. Rather than commercial competition, such applications may be directed more toward preventive maintenance and logistics management. [0076] The systems and methodologies described herein may also be applied in the health care industry, and more specifically, in intensive care units (ICUs) in medical centers. In such applications, a black box (data hub) may be utilized to get the real time sensor data from patients in an intensive care unit in a hospital. This data may then be uploaded to a service gateway, where it is accessible by various medical experts. Thus, for example, an expert located on the other side of the world may be able to advise a local medical practitioner based on a real time data feed from the patient. [0077] The systems and methodologies described herein may also be utilized for monitoring the real time production of oil and gas wells. In such an application, a data hub may be installed at the well head of a producing well, and pressure, temperature and flow sensors may be installed on the well head and connected to the data hub. The data hub software may then control the sampling rates of the different well head sensors and accumulate the sensor data in a data base. These sensor data may be uploaded to the data base in the service gateway, where various types of software routines (such as, for example, visualization, production analysis and the like) may be run on the service gateway for optimum production planning and management. Using the same system, sensors may be added to different artificial lift mechanisms, such as rod pumps, gas lifts and electrical submersible pumps. Consequently, condition based maintenance may be carried out for artificial lift equipment in addition to optimizing the performance of the artificial lifts. [0078] The systems and methodologies described herein may also be utilized for coal mine equipment performance management. In such an application, a data hub may be installed on heavy mining mobile equipment, and GPS, fuel level sensors and engine hour sensors may be installed on the equipment and connected to the data hub. The data hub software may then control the sampling rates of the different sensors, and may accumulate the sensor data in a database. This sensor data may then be uploaded to the database in the service gateway, where various software routines (such as equipment location, visualization, scheduling and equipment condition monitoring) may be run on the service gateway for optimum production planning and management. As an added advantage, the monitoring of fuel consumption vs. engine hours may be utilized to prevent fuel pilferage from heavy equipment in remote locations. [0079] The systems and methodologies described herein may also be utilized in procurement operations in the oil and gas industry. In such an application, all operational information available at the service gateway from an oil company's RTO operation may be used to determine the future scope of work for procuring services. Consequently, oil field service providers would be able to participate in the system with real time information concerning service equipment availability and the status of current services. Such an application would thus be able to connect the needs of the oil & natural gas field operators to the availability of a service company's equipment and to the company's service availability. This approach may allow different smaller oil companies with similar needs to be able to pool their needs to leverage the buying power associated with larger volumes. Consequently, service companies may be able to reduce their sales and marketing costs and the costs of missed opportunities by their use of such an application in which oil and natural gas companies will be able to publish their precise service needs. [0080] The systems and methodologies described herein may also be utilized for safety and service quality management in the oil and natural gas industry. In particular, a continuous service quality management system may be established for both the oil and natural gas field operators and the oil field service providers by monitoring drilling rig operations using an RTO system throughout the drilling operation. Such an application could be used to set up an auditable approval system for all mandatory safety and operational tests on a drilling well to ensure compliance with local safety regulations. Once data from real time tests is available on the service gateway, various reports may be generated to aid in managing operational excellence, as well as high safety standards. [0081] The above description of the present invention is illustrative, and is not intended to be limiting. It will thus be appreciated that various additions, substitutions and modifications may be made to the above described embodiments without departing from the scope of the present invention. Accordingly, the scope of the present invention should be construed in reference to the appended claims.

A platform is provided which facilitates collaboration among a plurality of users on a project (such as the exploration for oil or natural gas on an oil rig), data set and/or data stream. The platform ( 301 ) comprises (a) a data hub ( 315 ) configured to allow a plurality of users to store data on the data hub and to retrieve data from the data hub; (b) an interface ( 319 ) associated with the data hub which is independently configurable by each of said plurality of users, wherein each user has a set of user preferences associated with that user which controls the configuration of the interface when it is accessed by that user; (c) a plurality of data files stored on said hub, wherein each of said data files is associated with one of said plurality of users and is accessible via the interface; (d) a security system ( 331 ) which authenticates a user and which restricts access of the data files to those data files associated with the user; and (e) functionality allowing a user to manipulate data in the hub, including by use of external software loaded onto the hub.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to structures, structures to which anodized alumina nano-holes are applied, production methods thereof, electron-emitting devices, and image-forming apparatus. Particularly, the structures of the present invention can be applied to electron-emitting devices, image-forming apparatus, electrochromic devices, imaging tubes, and so on. [0003] 2. Related Background Art [0004] Considerable research is now under way on the electron-emitting devices having the properties of uniformity, fineness, high efficiency, and long life, as typified by flat panel displays. For forming microscopic electron-emitting regions of the devices, a lot of processes are performed by making use of the semiconductor processing techniques including photolithography, electron beam exposure, and so on. [0005] However, application of materials having microscopic structure (nano-structures) can be listed as a simple method of forming the electron-emitting regions uniformly and in a large area. Particularly, attention is being drawn to structures formed in a self-organizing manner. [0006] For the nano-structures, it is preferable to employ a porous film of alumina obtained by anodization of aluminum. First, the anodization of aluminum has such features that, when it is done in an aqueous solution of oxalic acid, phosphoric acid, or sulfuric acid, pores (nano-holes) are formed in nano-size so as to be surrounded by a barrier layer (alumina), thereby yielding a porous film; and that, when it is done in an aqueous solution of ammonium borate, ammonium tartrate, or ammonium citrate, the pores are not formed but a uniform alumina film (barrier film) is formed, thereby yielding a barrier film. [0007] [0007]FIGS. 2A, 2B, and 2 C are schematic views of films obtained by the anodization of aluminum, wherein FIG. 2A is a plan view of the porous film, FIG. 2B a cross-sectional view along line 2 B- 2 B of FIG. 2A, and FIG. 2C a cross-sectional view of the barrier film. The porous film of alumina is characterized by having such a specific geometrical structure that extremely fine, cylindrical pores having pore diameters 26 of several nm to several hundred nm are arrayed in parallel at spacing 25 of several ten nm to several hundred nm, as shown in FIGS. 2A and 2B. Then the array spacing of pores can be controlled by adjusting an electric current and a voltage during the anodization. [0008] Concerning this porous film of alumina, there are such attempts that an electron-emitting member is placed inside each of the holes to form an electron-emitting region and one electron-emitting device is constructed of an assembly of plural electron-emitting regions (e.g., Japanese Patent Applications Laid-Open No. 05-211030, Laid-Open No. 10-12124, and so on). This structure is characterized in that the sizes of the holes are very small. This makes use of the advantages that the electron-emitting regions have a small radius of curvature at the tip, so as to facilitate concentration of an electric field, and thus electron emission occurs readily and that the electric current is stable, because one electron-emitting device is constructed of a plurality of electron-emitting regions. [0009] There are, however, demands for decreasing dispersion among the individual electron-emitting regions and distribution of the electric field and for making the production process simpler. SUMMARY OF THE INVENTION [0010] For readily forming the electron-emitting devices having the even electron-emitting regions in a large area, it is useful to use the foregoing porous alumina film. In the conventional devices, however, uniformity of the electron-emitting regions was insufficient and unevenness of the field concentration resulting therefrom could lead to decrease in lifetimes of the electron-emitting regions. [0011] For solving it, it is desirable to improve the uniformity of the electron-emitting regions and improve durability against local field concentration. It is also necessary to simplify the production process. [0012] The present invention has been accomplished in order to solve the problems of the prior arts as described above, and an object of the invention is to provide structures with improved durability during the field concentration and with sufficient resistance to chain discharge breakdown and easy production methods of such structures, and also to provide structures with high uniformity, and electron-emitting devices and image-forming apparatus. [0013] The above object can be achieved by the following configurations and production methods according to the present invention. [0014] An aspect of the present invention is a structure comprising an electroconductive film, a layer placed on the electroconductive film and comprising aluminum oxide as a main component, a pore placed in the layer comprising aluminum oxide as a main component, and an electric conductor placed in the pore and comprising a material of the electroconductive film, wherein the electric conductor is porous and is electrically connected to the electroconductive film. [0015] Another aspect of the present invention is an electron-emitting device comprising an electroconductive film, a layer placed on the electroconductive film and comprising aluminum oxide as a main component, a pore placed in the layer comprising aluminum oxide as a main component, and an electron emitter placed in the pore and comprising a material of the electroconductive film, wherein the electron emitter is porous and is electrically connected to the electroconductive film. [0016] Another aspect of the present invention is a structure in which an enclosed substance is formed from a bottom portion of a pore formed by anodization of a film laid on an underlying electrode and comprising aluminum as a main component, wherein the enclosed substance comprises a constitutive element of the underlying electrode or an oxide thereof as a main component and is porous. [0017] Another aspect of the present invention is a method of producing a structure in which an enclosed substance is formed from a bottom portion of a pore formed by anodization of a film laid on an underlying electrode and comprising aluminum as a main component, the method comprising a step of carrying out anodization by use of a bath for forming a porous film, for the film comprising aluminum as a main component, a step of carrying out anodization by use of a bath for forming a barrier film, and a step of carrying out a thermal treatment. [0018] Another aspect of the present invention is a structure comprising: [0019] an electroconductive film; [0020] a layer placed on the electroconductive film and comprising aluminum oxide as a component; [0021] a pore placed in the layer comprising aluminum oxide as a component; and [0022] a porous electric conductor placed in the pore, electrically connected to the electroconductive film, and comprising a material of the electroconductive film, [0023] wherein the electroconductive film consists of two or more layers of films and at least one element out of elements included in every film is different from at least one element out of elements included in the other films. [0024] Another aspect of the present invention is an electron-emitting device comprising: [0025] an electroconductive film; [0026] a layer placed on the electroconductive film and comprising aluminum oxide as a component; [0027] a pore placed in the layer comprising aluminum oxide as a component; and [0028] a porous electron emitter placed in the pore, electrically connected to the electroconductive film, and comprising a material of the electroconductive film, [0029] wherein the electroconductive film consists of two or more layers of films and at least one element out of elements included in every film is different from at least one element out of elements included in the other films. [0030] Another aspect of the present invention is a structure in which a porous enclosed substance comprising a constitutive element of an underlying electrode or an oxide thereof as a component is formed from a bottom portion of a pore formed by anodization of a film laid on the underlying electrode and comprising aluminum as a component, wherein the underlying electrode consists of two or more layers of films and at least one element out of elements included in every film is different from at least one element out of elements included in the other films. [0031] Another aspect of the present invention is a method of producing a structure in which a porous enclosed substance comprising a constitutive element of an underlying electrode or an oxide thereof as a component is formed from a bottom portion of a pore formed by anodization of a film laid on the underlying electrode and comprising aluminum as a component, wherein the underlying electrode consists of two or more layers of films and at least one element out of elements included in every film is different from at least one element out of elements included in the other films. [0032] According to the structure of the present invention, the enclosed substance is electrically conductive and thus is applicable to the electron-emitting region. When the structure of the present invention is used as an electron-emitting device, even if the electric field is concentrated unevenly on the enclosed substance as an electron-emitting region to cause microdischarge, it will act as a current limiting resistance because of the porous structure, thereby making it feasible to provide the nano-structure resistant to discharge. [0033] When the pores (nano-holes) are regularly arrayed, the uniformity of shapes of the nano-holes is considerably improved and the electric field is also applied evenly as compared with irregular arrays, which makes it feasible to stabilize electric current values based on emission of electrons. Further, sizes of portions without the enclosed substance in the nano-holes are larger than those of portions with the enclosed substance, whereby the electric field becomes easier to concentrate and whereby electrons become easier to emerge from the nano-holes. [0034] According to the above features, the electron-emitting regions are protected from discharge, which can lengthen the lifetimes thereof. [0035] When a deriving electrode is formed at the upper part of the nano-hole in the structure of the present invention, electrons can be emitted efficiently. Here the distance between the deriving electrode and the electron-emitting region can be controlled with high accuracy by an anodization voltage during formation of the electron-emitting region. [0036] Further, the production method of the structure according to the present invention enables the enclosed substances serving as electron-emitting regions of uniform height to be formed readily and in a large area. BRIEF DESCRIPTION OF THE DRAWINGS [0037] [0037]FIGS. 1A and 1B are schematic views showing an embodiment of the structure according to the present invention; [0038] [0038]FIGS. 2A, 2B, and 2 C are schematic views of anodized alumina nano-holes; [0039] [0039]FIGS. 3A and 3B are schematic views showing states at respective fabrication stages of the structure according to the present invention; [0040] [0040]FIGS. 4C, 4D, 4 E, 4 F, and 4 G are schematic views showing states at respective fabrication stages of the structure according to the present invention; [0041] [0041]FIGS. 5A and 5B are views showing states of the enclosed substance in the structure of the present invention; [0042] [0042]FIGS. 6A and 6B are schematic views showing regulated nano-holes according to the present invention; [0043] [0043]FIGS. 7A and 7B are schematic views showing another embodiment of the structure according to the present invention; [0044] [0044]FIG. 8 is a profile of electric current for the first anodization in the sixth example of the structure according to the present invention; [0045] [0045]FIG. 9 is a table showing the results of visual observation after execution of the second anodization in 0.05 mol/l ammonium borate aqueous solution and at the applied voltage of 160 V in the sixth example of the structure according to the present invention; [0046] [0046]FIG. 10 is a table showing the results of observation to observe the heights of enclosed substances after formation of the enclosed substances by execution of the second anodization in 0.05 mol/l ammonium borate aqueous solution and at the applied voltage of 160 V in the seventh example of the structure according to the present invention; [0047] [0047]FIG. 11 is a table showing the results of measurement of electron emission ratio in the seventh example of the structure according to the present invention; [0048] [0048]FIGS. 12A, 12B, 12 C, and 12 D are schematic diagrams concerning the shape of an upper underlying electrode layer after production of the structure in the eighth example of the structure according to the present invention; and [0049] [0049]FIGS. 13A, 13B, and 13 C are schematic views of films obtained by the anodization of aluminum. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0050] The first structure of the present invention will be described below on the basis of the drawings. [0051] [0051]FIGS. 1A and 1B are schematic views showing an embodiment of the first structure of the present invention, wherein FIG. 1A is a plan view and FIG. 1B a cross-sectional view along line 1 B- 1 B of FIG. 1A. In FIGS. 1A and 1B, numeral 11 designates pores of nano-size (nano-holes) and 12 a barrier layer (alumina). Numeral 13 denotes enclosed substances (electron-emitting members) of an electric conductor, which have a porous shape, as shown in the cross-sectional shape of FIG. 5B. Numeral 14 represents a portion without the enclosed substances, 15 a portion with the enclosed substances, 16 an underlying electrode of an electroconductive film, 17 a substrate, 18 a deriving electrode, 19 an upper pore size (of the portion without the enclosed substances), 110 a lower pore size (of the portion with the enclosed substances), and 111 a spacing of the pores (nano-holes). In the present invention the “electric conductor” making the enclosed substances embraces metals and semiconductors. The “electric conductor” making the enclosed substances can also be referred to as a material having the band gap of not more than 4 eV and, preferably, not more than 3.5 eV. [0052] The pores (nano-holes) in the structure of nano-size (also called “nano-structure”) can be formed by use of a bath capable of forming a porous film by anodization of aluminum, e.g., by use of oxalic acid, phosphoric acid, sulfuric acid, or the like. Alumina portions surrounding the pores (nano-holes) at this time are the barrier layer (alumina) 12 . [0053] Then the porous enclosed substances (electron-emitting members) 13 can be made by use of a bath capable of forming a barrier film of uniform alumina film by the anodization of aluminum, e.g., by use of ammonium borate, ammonium tartrate, ammonium citrate, or the like. [0054] The enclosed substances (electron-emitting members) 13 are porous and are made of a material a main component of which is a constitutive element of the underlying electrode 16 of the electroconductive film or a material a main component of which is an oxide of the constitutive element. When the structure of the present invention is used as an electron-emitting device, it is preferable to carry out a reduction process described hereinafter to improve the electric conductivity of the enclosed substances 13 , because the enclosed substances 13 immediately after the formation according to the above method are often of oxide form. [0055] The height of the enclosed substances (electron-emitting members) 13 can be controlled by the applied voltage during the anodization in the bath for forming the barrier film. The voltage can be applied stepwise or directly up to a desired voltage to form the enclosed substances at an equivalent height. [0056] The barrier layer (alumina) 12 in the present invention represents the alumina portions separating the pores from each other in the porous film, and the barrier film does a uniform film of alumina obtained when the conventional anodization of aluminum is carried out in the bath of ammonium borate or the like, and is used in comparison with the porous film. Accordingly, when the anodization is carried out using the bath for forming the porous film in the present invention, a porous film is obtained. However, when the anodization of the porous film is subsequently carried out using the bath for forming the barrier film, the cylindrical enclosed substances are formed in the pores without forming the barrier film, which is the feature. [0057] The spacing 111 of the pores (nano-holes) can be controlled by the applied voltage during the anodization in the bath for formation of the porous film. The spacing Ill of the pores (nano-holes) to be formed can be controlled to a desired value by regularly forming pore-forming start points in a surface of aluminum before the anodization by FIB (Focused Ion Beam), a mold with regular projections, the lithography technology with light or an electron beam, or the like. [0058] The size 110 of the lower nano-holes (the portion with the enclosed substances) can be controlled by a time of a hole width enlarging process after the anodization in the bath for formation of the porous film. [0059] The size 19 of the upper nano-holes (the portion without the enclosed substances) can be controlled by a time of a hole width enlarging process after the anodization in the bath for formation of the barrier film, or after the thermal treatment. [0060] The latter hole width enlarging process can be carried out by dipping in phosphoric acid. The size can be controlled by the time. [0061] The substrate 17 in FIGS. 1A, 1B can be any material on which the underlying electrode 16 and the film the main component of which is aluminum can be formed. For example, the substrate can be either of materials flat and resistant to the temperatures of about 400° C.; for example, glasses, oxides such as SiO 2 , Al 2 O 3 , etc., semiconductors such as Si, GaAs, InP, and so on. The underlying electrode 16 can be either material selected from metals such as W, Nb, Mo, Ta, Ti, Zr, Hf, and so on. [0062] When the deriving electrode 18 in FIGS. 1A, 1B is formed so as to overlap like a cap at the upper end of each nano-hole, electrons can be emitted efficiently. [0063] A further preferred structure of the second form according to the present invention will be illustratively described below in detail with reference to the drawings. The structure of the second form described hereinafter is more suitable for the formation of the foregoing enclosed substances 13 in a good yield than the structure of the first form described above with reference to FIGS. 1A, 1B and others. [0064] It is, however, noted that the dimensions, materials, shapes, relative locations, etc. of the components used in the second form described hereinafter are by no means intended to limit the scope of the invention only to them unless otherwise stated in particular. [0065] Further, in the drawings described hereinafter, the same reference numerals will also denote members similar to those described with the drawings heretofore. [0066] The forms and examples of the second structure described hereinafter will also explain embodiments and examples of the electron-emitting devices, image-forming apparatus, nano-structures, and production methods thereof according to the present invention. [0067] [0067]FIGS. 7A and 7B are schematic views of an embodiment of the structure of the second form according to the present invention, wherein FIG. 7A is a plan view and FIG. 7B a cross-sectional view along line 7 B- 7 B of FIG. 7A. [0068] In FIGS. 7A and 7B, reference numeral 11 designates the nano-holes (pores) and 12 the barrier layer (alumina) as a layer containing aluminum oxide as a component. Numeral 13 denotes the enclosed substances (electron-emitting members) consisting of a porous electric conductor. Numeral 13 a represents upper enclosed substances, 13 b underlying-electrode-occupying enclosed substances, 14 the portion without the upper enclosed substances, 15 the portion with the enclosed substances, 16 the underlying electrode (electrode) consisting of an electroconductive film, 16 a an upper underlying electrode (first electrode), 16 b a lower underlying electrode (second electrode), 17 the substrate, 18 the deriving electrode, 19 the size of the upper nano-holes (the portion without the enclosed substances), 110 the size of the lower nano-holes (the portion with the enclosed substances), and 111 the spacing of the pores (nano-holes). [0069] However, the barrier layer 12 is not limited only to the layer containing aluminum oxide as a component, but it may also be a layer containing aluminum oxide as a main component. [0070] The pores 11 can be formed by use of a bath (oxalic acid, phosphoric acid, sulfuric acid, etc.) commonly known as those for formation of porous film in anodization of aluminum. [0071] The alumina portions surrounding the nano-holes at this time constitute the barrier layer (alumina) 12 . [0072] The porous enclosed substances (electron-emitting regions) 13 a and the underlying-electrode-occupying enclosed substances (electron-emitting regions) 13 b can be formed by use of the bath (ammonium borate, ammonium tartrate, ammonium citrate, etc.) capable of forming the barrier film being a uniform alumina film in the anodization of aluminum, as in the case of the enclosed substances of the first structure described previously. [0073] When the second structure of the present invention is used as an electron-emitting device, it is also preferable to carry out the process of enhancing the electric conductivity of the enclosed substances 13 by the reduction process, because the enclosed substances 13 immediately after the formation according to the above method are often of oxide form. [0074] In the second structure of the present invention, the “electric conductor” making the enclosed substances also embraces metals and semiconductors. The “electric conductor” making the enclosed substances can also be referred to as a material having the band gap of not more than 4 eV and, preferably, not more than 3.5 eV. [0075] During the production of the aforementioned first structure of the present invention, where the structure had the underlying electrode of only the W layer, electric current values during the anodization were observed in the step using the bath (oxalic acid, phosphoric acid, sulfuric acid, etc.) for the formation of the porous film in the anodization, and it was found from the observation that unless the anodization was ended at the current value equal to ⅚ of the constant current value, the yield was poor in the next step of forming the enclosed substances. [0076] However, when the structure is constructed like the second structure of the present invention wherein the upper underlying electrode 16 a is a film containing at least one element out of Nb, Mo, Ta, Ti, Zr, and Hf as a main component and the lower underlying electrode 16 b is a film containing W as a main component, the end condition can be expanded to the range of ⅚ to {fraction (1/12)} of the constant current value. [0077] However, the second structure of the present invention is not limited to the configuration wherein the upper underlying electrode (first electrode) 16 a is the film containing at least one element of Nb, Mo, Ta, Ti, Zr, and Hf as a main component and the lower underlying electrode (second electrode) 16 b is the film containing W as a main component, but it can also be of a configuration wherein the upper underlying electrode (first electrode) 16 a is a film containing at least one element of Nb, Mo, Ta, Ti, Zr, and Hf as a component and the lower underlying electrode (second electrode) 16 b is a film containing W as a component. [0078] In the second structure of the present invention, part of the upper underlying electrode 16 a is occupied by the lower enclosed substances 13 b . The upper underlying electrode 16 a is characterized in that it exists in the portions except for immediately below the pores 11 , or in the portions immediately below the junctions of the barrier layer 12 . [0079] The underlying-electrode-occupying enclosed substances 13 b are produced during the process of forming the second structure of the present invention. [0080] The height of the enclosed substances (electron-emitting members) 13 a is proportional to the voltage applied in the step using the bath (ammonium borate, ammonium tartrate, ammonium citrate, etc.) known as one for the formation of barrier film. The height also varies depending upon the material of the underlying electrode 16 . The height of the enclosed substances can be made equal by applying the voltage stepwise or directly up to a desired voltage. [0081] The spacing 111 of the pores can be controlled by the applied voltage during the anodization in the bath for the formation of the porous film, as described previously. When start points are regularly formed before the anodization by making use of the FIB (Focused Ion Beam), the mold with regular projections, the lithography technology with light or an electron beam, or the like, the spacing 111 of the nano-holes can be made constant regardless of locations. [0082] The size 110 of the lower nano-holes (the portion with the enclosed substances) can be controlled by the time of the hole width enlarging process after the anodization in the bath for the formation of porous film. The size 19 of the upper nano-holes (the portion without the enclosed substances) can be controlled by the time of the hole width enlarging process after the anodization in the bath for the formation of the barrier film, or after the thermal treatment. [0083] The substrate 17 can be any material on which the underlying electrode 16 and the film containing Al as a main component can be formed. [0084] For example, the substrate can be one selected, e.g., from the oxides such as SiO 2 , Al 2 O 3 , etc., and the semiconductors such as Si, GaAs, InP, etc. and being flat and resistant to the temperatures of about 400° C. The underlying electrode can be one selected from the metals such as W, Nb, Mo, Ta, Ti, Zr, Hf, and so on. [0085] The substrate 17 and the underlying electrode 16 can be made in an integral form, and the substrate 17 can be a metal sheet of W, Nb, Mo, Ta, Ti, Zr, Hf, or the like. When the substrate 17 is a metal sheet of W, Nb, Mo, Ta, Ti, Zr, Hf, or the like, the underlying electrode 16 consisting of two or more layers means that the substrate 17 is regarded as a single layer, and it is also feasible to achieve the effects of the present invention under such circumstances When the deriving electrode 18 in FIGS. 7A, 7B is formed so as to overlap like a cap at the upper end of each nano-hole, electrons can be emitted efficiently. [0086] When the enclosed substances 13 of the above structure are used as electron-emitting members, the foregoing structure functions as an electron-emitting device. [0087] When this electron-emitting device is combined with a member equipped with an image-forming member, e.g., like a fluorescent member, to be irradiated with electrons emitted from the electron-emitting device, an image-forming apparatus according to the present invention is constructed. EXAMPLES [0088] The present invention will be described below in further detail with examples thereof. In the following description, the anodization in the bath for the formation of the porous film will be called first anodization, and the anodization in the bath for the formation of the barrier film, second anodization. Example 1 [0089] The present example presents procedures of producing the structure of the present invention. [0090] The structure was produced according to the following procedures shown in FIGS. 3A to 4 G. [0091] 1) Layered films consisting of a film of tungsten 32 (50 nm thick) and a film of aluminum 31 (500 nm thick) were deposited on a glass substrate 33 by RF sputtering. Further, indentations were formed as pore-forming start points in a honeycomb pattern at intervals of 100 nm on the surface of aluminum by FIB (Focused Ion Beam). (cf. FIG. 3A) [0092] 2) The first anodization was carried out by dipping the film of aluminum 31 in 0.3M oxalic acid aqueous solution at 16° C. and applying the voltage of 40 V thereto. (cf. FIG. 3B) [0093] 3) Subsequently, the second anodization was carried out by applying the voltage of 200 V in 0.05M ammonium borate aqueous solution at 10° C. (cf. FIG. 4C) [0094] 4) The hole width enlarging process may be conducted in the above state, or the thermal reduction process may also be carried out first. The thermal reduction process reduces the enclosed substances (tungsten oxide) 35 into porous tungsten 36 . (cf. FIGS. 4D and 4E). [0095] 5) When the hole width enlarging process was carried out in the above step, the thermal reduction process is carried out herein; or, when the thermal reduction treatment was carried out in the above step, the hole width enlarging process is carried out herein. (cf. FIG. 4F) [0096] 6) In the final step, a film of tantalum becoming the deriving electrode 37 is formed by oblique incidence sputtering. (cf. FIG. 4G) [0097] Cross sections of samples produced according to the above two ways of production procedures were observed according to the procedures with FE-SEM. [0098] It was verified from the observation that, in each of the procedures, the structure corresponding to FIG. 3A was formed after the procedure 1 ), the structure corresponding to FIG. 3B after the procedure 2 ), the structure corresponding to FIG. 4C after the procedure 3 ), the structures corresponding to FIG. 4D and FIG. 4E after the respective procedures 4 ), the structure corresponding to FIG. 4F after the procedure 5 ), and the structure corresponding to FIG. 4G after the procedure 6 ). Example 2 [0099] The present example concerns the enclosed substances of the nano-structure. [0100] W, Si, Nb, Pt, Mo, Ta, Ti, Zr, and Hf films were deposited in the thickness of 50 nm on respective substrates by RF sputtering, thereby preparing nine types of substrates. After that, an aluminum film was further deposited in the thickness of 500 nm on each of the substrates. Then each of the substrates was subjected to the first anodization and the second anodization in the same manner as in Example 1. After that, they were observed with FE-SEM. For the sample with the tungsten film, the state of the enclosed substances subjected to the thermal reduction process was also observed with FE-SEM. [0101] It was verified from the observation that among the W, Si, Nb, Pt, Mo, Ta, Ti, Zr, and Hf films, the enclosed substances were formed only in the samples using the W, Nb, Mo, Ta, Ti, Zr, and Hf films, but the enclosed substances were not formed in the other samples of Si and Pt. [0102] Among the samples in which the enclosed substances were formed, the sample using tungsten was observed in detail, and it became clear therefrom that there existed voids of bubbles 42 in the enclosed substances (tungsten oxide) 41 before the thermal reduction process, as shown in FIG. 5A. It was also confirmed that the state after the thermal reduction process was that the enclosed substances were reduced into a binding state of particulate substances (porous tungsten), as shown in FIG. 5B. [0103] The packing factor after the formation of the enclosed substances 41 was approximately 78%, and the pacing factor of the enclosed substances 44 after the thermal reduction process was approximately 67%. Example 3 [0104] The present example concerns the applied voltage during the second anodization in the production of the structure and fluctuations of the height of the enclosed substances depending thereupon. [0105] The first anodization step was carried out under the same conditions as in Example 1. [0106] First prepared were four samples which were through the first anodization step as in Example 1. The second anodization step was also carried out under the conditions of the bath as in Example 1. [0107] In the second anodization step, voltages applied to the respective samples were 100 V, 130 V, 160 V, and 200 V, respectively. [0108] Evaluation [0109] After completion of the anodization, cross sections of the samples were observed with FE-SEM to estimate heights of the enclosed substances and rough fluctuation levels. The results are presented in Table 1 below. TABLE 1 Height of Fluctuation of Applied of enclosed height enclosed Voltage (V) substance substance (nm) 100 115 ±10 nm or less 130 175 ±5 nm or less 160 231 ±10 nm or less 200 300 ±5 nm or less [0110] It was found from Table 1 above that the relation between height of enclosed substances and applied voltage was a proportional relation and was generally given by the following equation. Height of enclosed substances ( nm )=[1.8×applied voltage ( V )]−60 [0111] Fluctuation amounts of the height of the enclosed substances were roughly estimated by observing about hundred enclosed substances and maximum fluctuations were obtained as in the above table, which confirmed that the fluctuations were small. Example 4 [0112] The present example concerns regularization of the nano-holes. [0113] The tungsten film (50 nm thick) and aluminum film (500 nm thick) were deposited on a glass substrate by RF sputtering and indentations were formed in the honeycomb pattern therein by FIB (Focused Ion Beam). The spacing of the indentations was 100 nm. [0114] Then the first anodization was carried out by applying the voltage of 40 V in 0.3M oxalic acid aqueous solution, and the second anodization by applying the voltage of 200 V in 0.05M ammonium borate aqueous solution. [0115] Cross sections of this sample were observed with FE-SEM. For comparison, a sample prepared without FIB was also observed. It was verified from the observation that, with the sample produced through the regularization, the normal nano-holes (enclosed substances) 53 were completely normal to the underlying electrode and all were straight, as shown in FIG. 6A. In contrast with it, with the sample produced without the regularization, the nano-holes were approximately normal to the underlying electrode but there were nano-holes 51 failing to reach the underlying electrode and enclosed substances 52 of small sizes, as shown in FIG. 6B. This affects the surrounding nano-holes, so as to cause dispersion of sizes of nano-holes. As a consequence, the electric field was concentrated more there than at the other enclosed substances, so that electric current values became unstable. [0116] It was, therefore, confirmed that the nano-holes thus regularized had high uniformity and were important to stabilization of electric current values. Example 5 [0117] The present example concerns the durability of the electron-emitting device using the structure. [0118] Samples were prepared as follows. By the method similar to that in Example 1, the tungsten film (50 nm thick) and aluminum film (500 nm thick) were deposited on a glass substrate by RF sputtering, and the first anodization and the second anodization were carried out by the voltage of 40 V and by the voltage of 200 V, respectively. After that, one sample was not subjected to the hole width enlarging process, but another sample was subjected to the hole width enlarging process in phosphoric acid 5 wt % for 50 minutes. In the subsequent step, the thermal treatment was carried out at 400° C. in a hydrogen atmosphere (which can be either a carbon monoxide atmosphere or a vacuum) for two hours. [0119] In the final step the deriving electrode of tantalum was formed by oblique incidence sputtering (cf. FIG. 1B). The distance between the deriving electrode and the electron-emitting regions was approximately 300 nm. The size of the electron-emitting regions at this time was 45 nm. The size of the portion without the electron-emitting regions in the upper part of the pores (nano-holes) was 45 nm or 77 nm, depending upon whether or not the hole width enlarging process was carried out. [0120] On the other hand, a sample for comparison was also prepared by burying nickel in the pores of the structure obtained through the hole width enlarging process in the same manner as the above sample, by electrodeposition to form the electron-emitting regions. [0121] Electrodes were attached to the two samples and the voltage was applied thereto in vacuum. Then emission of electrons was recognized near the applied voltage of 50 V from the two samples respectively having the electron-emitting regions of nickel and the electron-emitting regions of porous tungsten metal. [0122] It was verified that electric current values were stabler in the sample with the electron-emitting members of porous tungsten than in the sample with the electron-emitting members of nickel. Then the structure of the electron-emitting members of nickel and the structure of the electron-emitting members of tungsten were observed with TEM and it was found that the tungsten electron-emitting members were porous as shown in FIG. 5B but the nickel electron-emitting members were denser in structure than the tungsten electron-emitting members. [0123] It was thus verified from the above that the electron-emitting regions of the present invention were rarely affected by microdischarge because of the porous structure and sufficient current amounts were able to be ensured on a stable basis from the numerous electron-emitting regions. [0124] The electric current in the sample produced with the hole width enlarging process was approximately two times that in the sample produced without the hole width enlarging process. The reason is that the electric field was concentrated more. [0125] There will be presented examples of the second structure of the present invention to describe the production method thereof and the structure of the present invention. In the description hereinafter, the anodization in the bath (oxalic acid, phosphoric acid, sulfuric acid, etc.) for the formation of the porous film will be called first anodization, and the anodization in the bath (ammonium borate, ammonium tartrate, ammonium citrate, etc.) for the formation of the barrier film, second anodization. Example 6 [0126] The present example concerns the conditions under which the second structure of the present invention can be formed. [0127] A Ti film and a W film were deposited in the thickness of 5 nm and in the thickness of 50 nm, respectively, on a glass substrate by RF sputtering and thereafter an element of Nb, Mo, Ta, Ti, Zr, or Hf was deposited as an upper underlying electrode in the thickness of 2 nm on each substrate, thus preparing six types of substrates, four per type of substrate ( 24 substrates in total). Further, an Al film was deposited in the thickness of 500 nm on each of the substrates. [0128] [0128]FIG. 8 shows the end conditions a, b, c, and d in the first anodization in 0.3 mol/l aqueous solution of oxalic acid for the above samples (substrates). FIG. 8 is the profile of electric current during the first anodization in the present example. [0129] The conditions a, b, c, and d shown in FIG. 8, correspond to respective cases in which the electric current is reduced to (⅚)I 0 , (½)I 0 , (⅙)I 0 , and ({fraction (1/12)})I 0 , respectively, in order from the constant current value I 0 . [0130] Further, these samples were subjected to the second anodization in 0.05 mol/l aqueous solution of ammonium borate at the applied voltage of 160 V and the results of visual observation thereof are presented in the table shown in FIG. 9. FIG. 9 is the table showing the results of visual observation of the samples after the second anodization was carried out in the 0.05 mol/l aqueous solution of ammonium borate at the applied voltage of 160 V in the present example. The comparative example herein was a sample with only the W layer. [0131] It was verified from the above results that the stability in the anodization was able to be enhanced by provision of the new layer on the W layer. The reason for the destruction during the anodization is conceivably bubbles generated by the high voltage and it is speculated from this point that the new layer is also advantageous for enhancement of adhesion with the anodized alumina nano-holes. Example 7 [0132] The present example concerns the enclosed substances in the second embodiment of the present invention. Five types of substrates were prepared in such a way that a Ti layer and a W layer were deposited in the thickness of 5 nm and in the thickness of 50 nm, respectively, on each glass substrate by RF sputtering and thereafter an Nb layer was deposited as an upper underlying electrode in the thickness of 1 nm, 5 nm, 10 nm, or 20 nm for each of four substrates but was not deposited for the other substrate. After that, an Al film was deposited in the thickness of 500 nm on each of the substrates. [0133] Each of the substrates was subjected to the first anodization in 0.3 mol/l aqueous solution of oxalic acid and the first anodization was terminated when the current value I 0 was reduced to (⅓)I 0 . Then the second anodization was carried out in 0.05 mol/l aqueous solution of ammonium borate at the voltage of 160 V, thereby forming the enclosed substances. The height of the enclosed substances was observed by FE-SEM (Field Emission-Scanning Electron Microscopy) and the results thereof are presented in the table shown in FIG. 10. FIG. 10 is the table showing the observation results of the height of the enclosed substances in the samples in which the enclosed substances were formed by carrying out the second anodization in the 0.05 mol/l aqueous solution of ammonium borate at the voltage of 160 V in the present example. [0134] As apparent from the table shown in FIG. 10, the height of the enclosed substances increases with increase in the thickness of the Nb film. [0135] Then these samples were annealed at 400° C. in a reducing atmosphere for the purpose of enhancing the electric conductivity, and presence/absence of electron emission was checked under provision of the deriving electrode of Ta. The condition was expressed by a ratio of electron emission to that of the sample without the Nb layer. FIG. 11 shows a table of the results. FIG. 11 is the table showing the measurement results of electron emission ratio in the present example. [0136] The reason why the electron emission ratio decreased in the presence of the Nb film, as shown in FIG. 11, is conceivably that the oxide produced by the anodization of Nb was not reduced well by the reduction treatment by the heat at 400° C. [0137] It was found from the above that the structure was able to be constructed stably and the electron emission was good in the range where the thickness of the Nb film was 1 to 5 nm. Example 8 [0138] The present example concerns the underlying electrode in the second structure of the present invention. A Ti layer 5 nm thick and a W layer 50 nm thick were deposited on a glass substrate by RF sputtering and thereafter an Nb layer 2.5 nm thick was deposited as an upper underlying electrode. Then an Al film was deposited in the thickness of 500 nm thereon. [0139] This was subjected to the first anodization in 0.3 mol/l aqueous solution of oxalic acid at the applied voltage of 40 V. In the subsequent step the second anodization was carried out in 0.05 mol/l aqueous solution of ammonium borate. The second anodization was carried out at the applied voltage of 100 V, 150 V, or 200 V, and thereafter the upper underlying electrode was observed by FE-SEM. [0140] It was found from the observation that the upper underlying electrode was formed as shown in FIG. 12A with application of 100 V, as shown in FIG. 12C with application of 150 V, or as shown in FIG. 12D with application of 200 V. FIG. 12B shows a cross-sectional shape along line 12 B- 12 B of FIG. 12A. FIGS. 12A to 12 D are schematic diagrams concerning the shape of the upper underlying electrode layer after the production of the structure in the present example. [0141] It was confirmed from the above that, though varying its shape in the production steps, the upper underlying electrode layer existed finally in the forms as shown in FIGS. 12 A- 12 D and coupled the pores formed by the anodization, to the substrate. [0142] As described above, the present invention provides the following effects. [0143] When the electron-emitting device is constructed using the structure having the porous enclosed substances consisting of the electric conductor the main component of which is W, Nb, Mo, Ta, Ti, Zr, Hf, or an oxide of either element according to the present invention, the electron-emitting device is sufficiently resistant to the microdischarge and ensures stable emission current. [0144] When the pores are regularly arrayed by use of FIB (Focused Ion Beam), the straight enclosed substances are formed normally to the substrate, thus considerably enhancing the uniformity. This makes it feasible to apply the electric field uniformly as compared with the conventional electron-emitting devices and to stabilize the electric current values resulting from the electron emission. [0145] Further, the production method of the structure according to the present invention made it feasible to form the enclosed substances becoming the electron emission regions of uniform height readily and in a large area. [0146] Since the second structure of the present invention is characterized in that the oxide produced in the anodization of the layer in contact with the bottom portion of the pores is insoluble or hard to solve in alkali or acid, it becomes feasible to prevent weakening of adhesion between the underlying electrode and pores due to oxidation and erosion of the underlying electrode by repetition of the anodization steps, thereby preventing occurrence of structural destruction. [0147] It also became feasible to select the sufficiently gentle production conditions for production of samples. [0148] In particular, this effect was most prominent when Nb, Mo, Ta, Ti, Zr, or Hf was contained as a component in the layer in contact with the bottom portion of the anodized alumina nano-holes in the underlying electrode and W was contained as a component in the lower underlying electrode adjacent thereto.

Provided are electron-emitting devices improved in durability during concentration of an electric field and thus rarely suffering chain discharge breakdown. An electron-emitting device has an electroconductive film, a layer placed on the electroconductive film and containing aluminum oxide as a main component, a pore placed in the layer containing aluminum oxide as a main component, and an electron emitter placed in the pore and containing a material of the electroconductive film, and the electron emitter is porous and is electrically connected to the electroconductive film.

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation-in-part of U.S. patent application Ser. No. 29/196,339, filed on Dec. 24, 2003, the disclosure of which is incorporated herein by reference. BACKGROUND OF THE INVENTION The present invention relates generally to a fluid dispenser, and more particularly to a cost-effective dispenser assembly that is fully compatible with high-speed in-line filling apparatuses, capable of dispensing predetermined amounts of fluid materials, and has few components to assemble. Various types of dispensers for fluids are well known in the art. Dispenser's typically comprise a cartridge for holding the fluid material, as well as a spray, pump, or plunger to dispense the fluid material out of the cartridge. Some dispensers have a spray pump attached to a pump line that runs through a cartridge containing fluid material, such as perfume. When the user depresses the spray pump, fluid material flows through the line to the spray, and then onto the desired medium. Other dispensers, such as those used for caulking, have a cartridge filled with caulk, and a trigger mechanism which causes a plunger in the cartridge to push the caulk out of the cartridge. The shortcomings associated with these prior art dispensers concern their manufacture and assembly. Known dispensers typically require several pieces that must be manufactured and then assembled together. Some of the pieces, such as a separate applicator tip, are relatively small in size and can prove difficult to assemble. Known dispensers often have parts that need to be screwed together, or require additional adhesives or the like to secure the various components of the dispenser together. The configuration of known dispensers therefore requires extraneous parts and steps to complete the dispenser assembly process, which, in turn, drives up the costs for the manufacturer. These drawbacks are further compounded by the problems associated with filling known dispensers with fluid materials. Once a dispenser has been manufactured, dispenser manufacturers typically solicit their dispensers to companies desiring to sell fluid products. For example, a cosmetic company may wish to purchase a dispenser designed to dispense a fluid lipstick, lotion, or the like. After purchasing the empty dispensers from a dispenser manufacturer, the cosmetic company will then proceed to fill the dispensers with its own product using a filling apparatus and process. There are many problems, however, associated with the purchase and subsequent filling of known dispensers by a purchasing company. It is not cost-effective to fill known dispensers with fluid product using standard high-speed filling apparatuses and processes. Such dispensers often vary in shape and size and are not readily adaptable to preexisting high speed filling machines utilized by a particular company. For example, the shape of the dispenser body may not be compatible with the parts of the preexisting filling machine used to hold the dispenser during the filling process, or the opening of the cartridge may not be large enough (or even too small) to receive the nozzle of the filling apparatus that dispenses the fluid material from the filling apparatus to the cartridge. To remedy these problems, the cosmetic company is therefore forced to purchase new filling machines, and/or adapters, such as funnels, or custom made holders for the dispenser, commonly referred to as pucks, to make pre-existing filling machines and dispensers compatible with one another. In some situations, it is too costly to adapt a preexisting filling machine to fit a particular dispenser, which results in the inability to use such a dispenser in a high speed filling process, or similar type of filling process. This often forces the cosmetic company to either select an alternative dispenser, or to use an alternative slower process. Each of these problems is a costly venture for a purchasing company, who then passes the additional cost on to the consumer. There are also additional costs associated with assembling the dispenser once the dispenser has been filled with the desired fluid material. In the filling process, typically a separate cartridge must first be filled by the filling apparatus, and then inserted into the dispensing device. Thereafter, the dispenser must be completely assembled and sealed. This task proves to be especially cumbersome when the dispenser has several components that need to be assembled after the filling process is completed. The added steps and time needed to assemble and fill such dispensers, slows down the filling process and drives up the filling costs. It also compromises the quality and integrity of the fluid material sitting in the dispenser because it leaves the fluid materials subject to contamination by dust, air, etc., until the dispenser is sealed. These problems are evident in U.S. Application No. 2003/0123921 to Abbas (“Abbas”), which is directed toward an instrument preferably for applying a fluid material of low viscosity to a surface. FIG. 19 discloses a fluid dispenser that comprises a cartridge of fluid, a holder, an applicator tip, a pump and pump housing, and a retaining ring for holding the pump housing within the holder. Force applied to the cartridge causes fluid in the cartridge to flow from the pump to the holder, and the applicator tip. FIG. 23 of Abbas discloses a toothbrush dispenser preferably for dispensing a fluid of low viscosity, such as a liquid cleaner, mouthwash or perfume, onto teeth. The toothbrush dispenser comprises a cartridge of liquid cleaner having a pump, an outer holder for the cartridge, an applicator tip or toothbrush head attached to the holder, and a feeder line from the cartridge to the applicator tip. FIG. 27 shows a configuration similar to FIG. 23 , the primary differences being that the applicator tip is a pad, and that instead of a feeder line from the inner cartridge to the applicator tip, there is an inking region that collects fluid material dispensed from the cartridge, and then dispenses the fluid material to the applicator tip. In both FIGS. 23 and 27, force applied to the cartridge causes fluid material from the cartridge to flow into either the feeder line or inking region, and then to the applicator tip. Despite the seemingly relative simplicity of these embodiments, there are still costly drawbacks associated with the manufacture of the Abbas dispensers, and the subsequent filling of the Abbas dispensers with fluid materials. The Abbas dispenser is comprised of several parts that require assembly. The applicator tip must be inserted and secured onto the holder, an inner cartridge containing fluid material is inserted into the holder, a retaining ring must also be inserted into the holder to contain the inner cartridge within the holder (or the inner cartridge must be screwed into the holder), a pump mechanism must be attached to the cartridge, and then the cartridge must be sealed with a cap. Prior to installation of the cartridge, the cartridge must first be filled with fluid material. Abbas is designed so that the cartridge is filled with fluid material and then temporarily sealed. The cartridge is then placed into the holder in its sealed form, and later punctured by the tip of the pump when it is desired to permit the free flow of fluid material into the applicator. This design is believed to prevent the pre-assembly of the cartridge into the holder when the cartridge is provided to a filling manufacturer because pre-assembly might cause premature puncturing of the cartridge. Moreover, the design of the cartridge typically requires additional screwing or the use of adhesives or the like to secure the cartridge within the holder. In this regard, it is believed that the Abbas dispenser cannot be sent to a filling manufacturer in a preassembled form, filled, and then simply sealed. Thus, the Abbas dispenser requires the steps of filling the cartridge, sealing the cartridge, and only then installing and securing the cartridge within the holder. The added step in the Abbas dispenser assembly process exemplifies the problems associated with the Abbas dispenser and prior art dispensers. It is therefore beneficial to provide a dispenser assembly, such as those embodiments disclosed by the present invention, that is cheaper to manufacture, easy to assemble, maintains the integrity of the fluid material in the dispenser, and is compatible with pre-existing high speed filling machines. SUMMARY OF THE INVENTION The present invention is designed to overcome the shortcomings associated with the disclosure of Abbas and other known fluid dispensers by providing a dispenser assembly that is cheaper to manufacture, requires few parts to assemble, and is readily compatible with standard high speed filling machines. As discussed more fully herein, the present invention requires few parts; namely, an end cap, a fluid insert containing fluid materials, and an outer casing. Unlike the prior art disclosures, each of these parts can be assembled together without the use of additional parts, such as adhesives or retaining rings, or steps such as screwing the different components together. The present invention further permits a manufacturer to sell a dispenser assembly to cosmetic companies and the like seeking to dispense their products (such as lotions, gels, etc.) into dispensers using a high speed filling process. The present invention is fully compatible with standard high speed filling apparatuses. The dispenser assembly can be provided to cosmetic companies and the like in an almost completely assembled manner and placed directly onto standard high speed filling apparatuses. The only assembly required after filling is the addition of a seal cap to seal the dispenser once the cartridge of the dispenser has been filled with the desired fluid material. In accordance with another important feature of the present invention, the capping process can also take place as part of the high speed filling process, further cutting down on the assembly time. The steps required to assemble the fluid dispenser greatly differs from known dispensers, which require the separate steps of filling the cartridge, sealing the cartridge, and then assembling the cartridge into the holder. The few steps required to assemble and fill the dispenser assembly according to the present invention increases production, while minimizing overall costs. Accordingly, various dispenser assemblies in accordance with the present invention are disclosed which achieves each of these shortcomings. According to one aspect of the present invention, there is provided an instrument for applying a predetermined amount of fluid material to a surface comprising a fluid insert and an outer casing. The fluid insert has a first end and a second end, and a protruding ridge arranged on an exterior of the fluid insert between the first end and the second end. The outer casing has a hollow interior for receiving the fluid insert therein, a first end and a second end, and a pump actuating surface. The outer casing further includes an applicator tip integrally formed with the outer casing at the first end for dispensing fluid material from the outer casing, and an interior ridge arranged within the hollow interior between the first end and the second end for securing the fluid insert within the outer casing when the protruding ridge of the fluid insert is positioned between the interior ridge of the outer casing and the first end of the outer casing. There is also a pump arranged at the first end of the fluid insert that has a pump body and a pump tip. The fluid insert is constructed and arranged to be movable within the outer casing between a stationary position and an actuated position, wherein the pump is in an extended position when the fluid insert is in the stationary position, and the pump is in a retracted position within the pump body when the pump tip is in engagement with the pump actuating surface of the outer casing when the fluid insert is in the actuated position. The pump is operative to dispense a predetermined amount of fluid material as the fluid insert is moved from the stationary position to the actuated position within the outer casing. According to another aspect of the present invention, there is provided an instrument for applying a predetermined amount of fluid material to a surface comprising a fluid insert for storing fluid material, a pump, and an outer casing. The fluid insert has a first end, a second end, and a notch arranged between the first end and the second end. The pump is arranged at the first end of the fluid insert and has a pump body, and a pump tip. The outer casing has a first end and a second end, a tab arranged between the first end and the second end, and an applicator for applying fluid material dispensed into the outer casing. The outer casing is constructed and arranged to receive the fluid insert so as to permit movement of the fluid insert within the outer casing between a first position and a second position. The tab is constructed and arranged to fit within the notch on the fluid insert so as to guide movement of the fluid insert when the fluid insert moves within the outer casing from the first position to the second position. The fluid insert is in the first position when the pump tip is in a fully extended position, and the fluid insert is in the second position when the pump tip is retracted into the pump body. The pump is operative to dispense fluid material into the outer casing when the fluid insert is moved from the first position to the second position. In accordance with another aspect of the present invention, there is provided an instrument for applying a predetermined amount of fluid material that has a fluid viscosity ranging from 1000 centipoise (cps)-10,000 cps to a surface. The instrument comprises a fluid insert for storing fluid material, and an outer casing. The fluid insert has a first end and a second end, and a notch arranged on the fluid insert displaced from the first end of the fluid insert. It has a pump capable of pumping fluid material that has a fluid viscosity ranging from 1000 centipoise (cps)-10,000 cps. The pump is arranged at the first end of the fluid insert, and has a pump body and a pump tip. The pump is operative to dispense fluid material in response to movement of the pump tip. The outer casing has a first end and a second end, a tab arranged on the interior thereof, and an applicator for dispensing the fluid from the pump of the fluid insert within the outer casing. Tab constructed and arranged to fit within the notch so as to guide movement of the fluid insert within the outer casing. In accordance with still another aspect of the present invention, there is provided a device for dispensing a predetermined amount of fluid material to a surface comprising an outer casing and a fluid insert for housing fluid material. The outer casing has first and second ends, an applicator at the first end, a first ridge arranged on an interior of the outer casing and displaced from the second end, and a second ridge arranged within the interior of the outer casing between the inner ridge and the applicator. The fluid insert has a raised band on the surface thereof, the fluid insert being constructed and arranged to fit within the outer casing so that the raised band is arranged between the first and second ridges of the outer casing. The fluid insert is movable from a first position to a second position within the outer casing to disperse fluid material. The fluid insert is in a first position when the raised band is adjacent to the first ridge of the fluid insert, and the fluid insert is in a second position when the raised band is adjacent to the second ridge of the fluid insert. The fluid insert dispenses a predetermined amount of the fluid material contained in the fluid insert through the applicator of the outer casing when the fluid insert moves from the first position to the second position. In accordance with yet another aspect of the present invention, there is provided an instrument for dispensing a predetermined amount of fluid material comprising an outer casing and a fluid insert. The outer casing has an interior chamber, a first tab and a second tab arranged within the interior chamber, and an applicator integrally formed with the outer casing. The fluid insert is arranged and constructed to fit within the outer casing, and has a first notch and a second notch, a pump with an internal check valve, and a stop having a first side and a second side. The fluid insert is rotatable within the outer casing between a first position and a second position. The fluid insert is in the second position when the second side of the stop is adjacent to the second tab and the second notch is displaced from the second tab. The fluid insert is in the first position when the first tab is aligned with the first notch, and the first side of the stop is adjacent to the first tab. The dispenser assembly is adapted to dispense a predetermined amount of the fluid material from the fluid insert through the applicator when the fluid insert is in the first position. In accordance with another aspect of the present invention, there is provided a dispenser assembly for dispensing a predetermined amount of fluid material comprising a fluid insert and an outer casing. The fluid insert has a body including a first end and a second end, a hollow chamber for storing a fluid material, a seal cap mounted to the first end for sealing the fluid insert, a pump connected to the second end for dispensing a predetermined amount of fluid material, a notch on the body displaced from the second end, and a protruding ridge displaced from the first end. The outer casing has an interior chamber for receiving the fluid insert and a first end and a second end. The applicator is arranged at the first end for applying the fluid material dispensed from the pump of the fluid insert to a surface. There is at least one tab arranged within the interior chamber of the outer casing and it is constructed and arranged to fit within the notch so as to guide movement of the fluid insert within the outer casing. The outer casing also has a ridge arranged within the interior chamber of the outer casing that is operative to restrict removal of the fluid insert when the fluid insert is assembled within the interior chamber. In accordance with a further aspect of the present invention, there is provided a method of filling a dispenser assembly using a high speed filling apparatus. First, a pre-assembled dispenser assembly is provided that has an end cap, an outer casing, and an inner fluid receiving body. The outer casing has a first end and a second end, and an applicator at the first end. The inner fluid receiving body has a first end and a second end, a pump arranged at the first end of the inner fluid receiving body, and an opening arranged at the second end of the inner fluid receiving body. The inner fluid receiving body is pre-assembled in the outer casing so that the inner fluid receiving body closes the second end of the outer casing, and the end cap is arranged over the applicator of the outer casing. Second, the pre-assembled dispenser assembly is placed directly onto a filling apparatus. Third, the inner fluid receiving body is filled with a fluid material through the opening of the inner fluid receiving body. Fourth, the inner fluid receiving body of the partially pre-assembled dispenser assembly is sealed with a seal plug so as to provide a fully assembled and filled dispenser assembly. These and other features and characteristics of the present invention will be apparent from the following detailed description of preferred embodiments, which should be read in light of the accompanying drawings in which corresponding reference numbers refer to corresponding parts throughout the several views. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an unassembled cap, outer casing, and fluid insert according to an embodiment of the present invention. FIG. 2 is a perspective view of an assembled cap, outer casing, and fluid insert of the dispenser assembly shown in FIG. 1 . FIG. 3 is a cross-sectional view of the outer casing shown in FIG. 1 . FIG. 4 is an exploded cross-sectional view of the left end of the outer casing shown in FIG. 3 . FIG. 5 is an exploded cross-sectional view of the right end of the outer casing shown in FIG. 3 . FIG. 6 is a front view of the left end of the outer casing shown in FIG. 3 . FIG. 7 is a rear view of the right end of the outer casing shown in FIG. 3 . FIG. 8 is a perspective view of an unassembled inner casing shown in FIG. 1 . FIG. 9 is a cross-sectional view of the body of the fluid insert shown in FIG. 8 . FIG. 10 is a cross-sectional view of section A-A shown in FIG. 9 . FIG. 11 is an exploded cross-sectional view of the right side of the fluid insert body shown in FIG. 9 . FIG. 12 is a cross-sectional view of the assembled fluid insert body, pump, and seal cap of the fluid insert shown in FIG. 1 . FIG. 13 is a front view of the assembled fluid insert and outer casing shown in FIG. 1 . FIG. 14 is a top view of the seal plug of the fluid insert shown in FIG. 12 . FIG. 15 is a cross-sectional view of the seal plug shown in FIG. 14 . FIG. 16 is an exploded cross-sectional view of the ridges shown on the seal plug shown in FIG. 15 . FIG. 17 is a cross-sectional view of the seal cap according to an alternative embodiment of the present invention. FIG. 18 is a cross-sectional view of a seal cap and diaphragm according to an embodiment of the present invention. FIG. 19 is a top view of the diaphragm shown in FIG. 18 . FIG. 20 is a perspective view of the end cap shown in FIG. 1 . FIG. 21 is a cross-sectional view of the end cap shown in FIG. 20 . FIG. 22 is a cross-sectional view of an end cap according to an alternative embodiment of the present invention. FIG. 23 is an alternative embodiment of the fluid dispenser assembly according to the present invention. DETAILED DESCRIPTION In describing the preferred embodiments of the subject matter illustrated and to be described with respect to the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. The present invention is generally directed to a dispenser assembly 100 shown in FIG. 1 for dispensing predetermined amounts of fluid materials. The material, such as lotion, is stored within a fluid insert 108 and dispensed therefrom in response to pressure applied by a user onto the fluid insert 108 , which, in turn, actuates the pump 117 . The dispenser also contains an outer casing 106 that holds the fluid insert 108 . It is to be understood that the dispenser for fluid materials of the present invention may be utilized to dispense various liquids, pastes, semi-liquids, semi-solids, gels, and the like. Such materials are preferably derived from the cosmetics industry and may include gels, medicated creams and lotions, and the like to be dispensed using the dispenser of the present invention. Also for convenience, all such materials will be generally referred to as fluid materials, although they may have semi-solid, paste-like or other consistencies. Referring to FIG. 1 , the dispenser assembly 100 is preferably comprised of a dispenser cap 102 , an outer casing 106 , and a fluid insert 108 . The dispenser assembly 100 is constructed and arranged so that the fluid insert 108 is disposed and secured within the outer casing 106 , and the dispenser cap 102 fits over the outer casing 106 . The dispenser cap protects the applicator 104 from being contaminated or otherwise damaged. As shown in FIG. 2 , when these components are assembled together, they form an elongated cylindrical dispenser assembly that is preferably in the shape of a tubular pen, although the dispenser may take on a variety of alternate shapes, such as animals, flowers, or any desired shape. Referring to FIGS. 3 and 4 , the outer casing 106 is preferably a hollow tube with an elongated outer body 114 having an applicator 104 , and a connector portion 110 that connects the applicator 104 to the outer body 114 . The outer body 114 preferably has a larger diameter than the applicator 104 and connector 110 . In this regard, the connector portion 110 preferably has a diameter greater in size than the applicator 104 , but smaller than the outer body 114 . The connector 110 and applicator 104 are both preferably integrally formed with the outer body 114 so as to minimize the number of parts needed to manufacture and assemble the outer casing 106 , as well as to decrease the overall costs associated with the manufacture and assembly of the dispenser assembly 100 . It should be appreciated, however, that the outer casing 106 may be formed from separate components that are assembled together, and that the connector portion 110 may be removed. The applicator 104 preferably has rounded ends 103 and an opening 107 (see also FIG. 6 ) through which the fluid material from the fluid insert 108 (see FIG. 1 ) is dispersed. As shown in FIGS. 3 , 4 , and 7 , a raised wall 600 arranged on the interior side 117 of the applicator 104 surrounds the opening 107 . The wall 600 helps guide the tip 120 (see FIG. 1 ) of the fluid insert 108 into the opening 107 when the fluid material is dispensed from the fluid insert 108 . It should be appreciated that the applicator can also take on a variety of alternate constructions such as a spray device, brush, roller, scrubbing pad, and the like. Referring to FIGS. 3 and 5 , an edge 302 and protruding inner casing ridge 304 is arranged towards the open end 116 of the interior 117 of the outer casing 106 . In a preferred embodiment, one inner casing ridge 304 is located along the perimeter of the interior 117 of the outer casing 106 , although it should be appreciated that more than one ridge may be used. The edge 302 and innermost edge 303 of the inner casing ridge 304 define the boundaries of a pumping region 306 which, as best shown in FIG. 5 , has a diameter that is slightly larger than the diameter of the remainder of the interior 117 . In a preferred embodiment, the diameter of the pumping region 306 will differ from that of the remainder of the outer body 114 on the order of 0.012±0.003 inches. A similar outer region 309 preferably having a reduced diameter extends from the outermost edge 307 of the inner casing ridge 304 to the open end 116 of the outer casing 106 . Referring to FIG. 5 , the diameter of the area in which the protruding inner casing ridge 304 is located preferably decreases so as to eventually equal the diameter of the pumping region 306 . In the embodiment shown, there is an angular slope 320 that slopes at an angle of 10° from the highest point 311 of the inner casing ridge 304 to the pumping region 306 . It should be appreciated that the size and slope of the ridge may be increased or decreased. As shown in FIGS. 3 , 4 , and 7 , tabs 300 are arranged on opposed surfaces at the front end of the interior 117 of the outer casing 106 . The tabs 300 are elongated and have a first end 308 located at the beginning of the connector portion 110 and a second end 310 located towards the lower end of the body 114 . As will be discussed fully herein, the tabs are designed to help guide the movement of the fluid insert 108 when the dispenser assembly 100 is actuated so as to dispense fluid material. The size of the tabs may therefore vary based upon the size of the fluid insert 108 and/or the travel length of the fluid insert 108 when it moves from a stationary position to an actuated pumping position. Accordingly, the length of the tabs 300 may be altered to suit the desired movement of the dispenser assembly 100 . Referring to FIG. 8 , the components of the fluid insert 108 according to an embodiment of the present invention are shown. The fluid insert 108 is adapted to contain the fluid material to be dispensed within its interior chamber 126 . The fluid insert 108 is comprised of a pump 117 , a seal plug 132 , a fluid insert body 128 , having a first end 125 , a second end 127 , a transition region 124 , and a fluid insert band 130 arranged near the second end 127 of the fluid insert 108 . As shown in FIG. 9 , the fluid insert body 128 is preferably tapered in shape, the diameter of the fluid insert 108 decreasing in size from its second end 127 to the first end 125 . The fluid insert 108 must have an overall diameter that is small enough to fit within and be capable of axially moving within the outer casing 106 (see FIG. 3 ). Preferably, the fluid insert is at least 0.0035±0.0015 inches smaller than the outer casing. As shown in FIGS. 9 and 10 , a first notch 301 is arranged on the exterior of the fluid insert body 128 and a second notch 301 ′ is arranged on the opposed exterior side of the fluid insert body 128 . The notches 301 , 301 ′ are recessed so that they can receive the tabs 300 of the outer casing 106 (see FIG. 3 ) when the dispenser assembly 100 is fully assembled. The notch edge 305 of the notch 301 also creates a stop when the tab 300 (see FIG. 3 ) of the outer casing 106 is inserted into the notch 301 . As shown in FIGS. 9 and 11 , there are preferably two ridges 133 , 135 arranged near the second end 127 of the fluid insert body 128 . The fluid insert ridges 133 , 135 are arranged along the inner perimeter of the interior 138 of the fluid insert body 128 . In the embodiment shown, there are two ridges shown, however, it should be appreciated that any number of ridges may be utilized, and only one ridge is required. As shown in FIG. 11 , the fluid insert ridges 133 , 135 have diameters greater than the remainder of the interior 138 of the fluid insert 108 . Preferably, the diameters of the fluid insert ridges 133 , 135 are 0.0125±0.0015 inches greater than the diameter of the remainder of the interior 138 , although the fluid insert ridges 133 , 135 may differ based on any desired measurements. As will be discussed more fully herein, the fluid insert ridges 133 , 135 can receive a complementary seal plug ridge 136 (see FIG. 8 ) from the seal plug 132 to secure the seal plug 132 within the fluid insert 108 . Referring to FIGS. 8 , 14 , and 15 the seal plug 132 is circular in shape with rounded edges 134 and an inner wall 137 . The seal plug 132 is used to seal the fluid insert 108 so as to prevent fluid from leaking out of the fluid insert 108 , or contamination of the fluid material stored in the fluid insert 108 . As best shown in FIG. 15 , an inner wall 137 is recessed away from the edge 142 of the seal plug 132 and engages the interior chamber 126 (see FIGS. 8 , 9 ) of the fluid insert 108 . As shown in FIGS. 15-16 , the seal plug 132 has two seal plug ridges 136 that are raised and have a height greater than the remainder of the inner walls 137 . The outer end 140 of the seal plug 132 preferably has an indentation 145 that makes it easier for users to apply force to the fluid insert 108 when it is desired to dispense fluid material form the fluid dispenser assembly 100 . In order to connect the seal plug 132 to the fluid insert body 128 , each of the seal plug ridges 136 engage the fluid insert ridges 133 , 135 arranged on the interior 138 of the fluid insert body 128 . (See FIGS. 9 and 11 .) The resistance created by the fluid insert ridges 133 , 135 and seal plug ridges 136 , permits the seal plug 132 to securely snap into place within the fluid insert body 128 . The seal plug 132 is secured within the fluid insert body 128 once the seal plug ridges 136 are locked into position within the fluid insert ridges 133 , 135 . Additional adhesives or the like may be used to further secure the seal plug 132 in the fluid insert body 128 , although it is not necessary. Referring to FIGS. 17-19 , an alternative embodiment of a seal plug 132 ′ is shown. The seal plug 132 ′ is substantially similar to the seal plug shown in FIGS. 14-16 , however the alternative seal plug 132 ′ has a diaphragm holder 150 that is in the shape of an elongated triangle. The base of the diaphragm holder 150 is attached to the interior 143 of the seal plug 132 ′. Diaphragm 152 is designed to fit within the interior of the seal plug 132 ′. The diaphragm 152 is circular in shape and its center rests upon the center 156 of the diaphragm holder 150 . It is not securely fastened to the diaphragm holder 150 and is held in place by the fluid material contained in the interior chamber 126 of the fluid insert 108 (See FIG. 9 .) The diaphragm 152 also has scrapers 154 which extend from the main body 158 of the diaphragm 152 . When the fluid insert 108 withdraws fluid material from the interior chamber 126 , the weight of the diaphragm 152 aids in pushing the fluid material towards the pump 117 , while also scraping the walls of the interior chamber 126 , as the diaphragm moves closer to the pump 117 . Due to the taper of the fluid insert 108 , the diaphragm 152 is preferably slightly smaller than the seal plug 132 so that it can extend down the length of the fluid insert body. It is also preferably comprised of a Low Density Polyethylene (commonly referred to as LDPE) material, which is very thin and flexible and permits the diaphragm 152 to give and flex as it slides down the fluid insert body 128 . The diaphragm may also be constructed and arranged to match the taper of the fluid insert 108 . It should be appreciated that any type of diaphragm may be used to scrape fluid materials from the sides of the interior of the fluid insert. Referring back to FIG. 8 , the pump 117 is a standard pump with an internal check valve, that is preferably capable of dispensing fluid materials of high viscosity, such as those known in the art. For example, an EMSAR Pump, PAV (A45) series having a 130 mcl micro liter output may be utilized. In a preferred embodiment, the pump is capable of pumping fluids having a fluid viscosity ranging from of at least 1000 cps to 10,000 cps, although a pump capable of pumping fluids having a much lower or much higher viscosity is also contemplated. The body of the pump 117 preferably has three tapered regions, a main pump body 122 , an intermediate pump body 123 , and an intake region 118 , respectively decreasing in size and length. The pump 117 preferably has an internal ball check valve 121 to regulate the amount of air permitted to enter into the interior chamber 126 of the fluid insert 108 . As shown in FIG. 12 , when the pump 117 is assembled into the fluid insert body 128 of the fluid insert body 128 , the pump 117 is only partially arranged within the fluid insert body 128 . The intake region 118 and intermediate body 123 of the pump 117 are located within the fluid insert body 128 . A portion of the main pump body 122 is located within the transition region 124 , while the remaining portion of the main pump body 122 , as well as the tip 120 , protrude from the fluid insert body 128 . The shapes and sizes of the transition region 124 of the fluid insert body 128 and main pump body 122 of the pump 117 are complementary to one another so that the pump 117 can securely fit into the transition region 124 of the fluid insert body 128 . The taper of the main pump body 122 prevents the pump 117 from completely entering the interior of the fluid insert body 128 , while permitting for a secure fit within the fluid insert body 128 . The main pump body 122 also rests against the transition region edge 113 to prevent the pump 117 from further advancing into the fluid insert body 128 . Adhesives or the like may be applied to the pump 117 and transition region 124 so as to provide additional security for the pump 117 to remain within the intermediate body 123 of the fluid insert 108 . However, due to the secure fit of the pump 117 within the fluid insert body 128 , additional adhesives are not necessary. It should be appreciated that the shapes and sizes of the complementary parts provide a cost effective means for securely fastening the parts of the fluid insert 108 together. The dosage of fluid desired to be dispensed from the dispenser assembly 100 will determine the size of the pump incorporated into the dispenser assembly 100 . For example, if it is desired to dispense 100 mcl of a fluid product, a standard pump capable of dispensing 100 mcl of a fluid product can be purchased for use in the dispenser assembly 100 of the present invention. Similarly, if it is desired to dispense 200 mcl of fluid product, a standard pump capable of dispensing 200 mcl of fluid can be utilized in the dispenser assembly 100 . The dimensions of the dispenser assembly 100 may need to be adjusted to fit the differing sizes of pumps desired. In the embodiment shown, a 130 mcl pump is used, and the size of the fluid insert body 128 and transition region 124 are complimentary to the pump configuration. When it is desired to assemble the components of the dispenser assembly 100 , the assembled fluid insert 108 ( FIG. 1 ) is inserted into the outer casing 106 ( FIG. 1 ). The fluid insert 108 is secured in the outer casing 106 when the band 130 (see FIG. 8 ) located on the exterior side of the fluid insert 108 is located in the pumping region 306 of the outer casing 106 . When the fluid insert 108 is inserted into the outer casing 106 , the band 130 must pass through the inner casing ridge 304 of the outer casing 106 and into the pumping region 306 . Referring to FIG. 13 , when the dispenser assembly 100 is in a stationary position, the fluid insert 108 will sit within the outer casing 106 , allowing a portion X and the seal cap 132 of the fluid insert 108 to protrude beyond the open end 116 of the outer casing 106 . The outermost edge 131 of the band 130 (see FIG. 8 ) will rest against the innermost edge 303 of the inner casing ridge 304 (see FIG. 3 ). In this stationary position, there is a distance X from the seal cap 132 to the edge 116 of the outer casing 106 . As shown in FIG. 13 , when it is desired to dispense fluid from the dispenser assembly 100 , a Force F is applied to the end 132 of the fluid insert 108 . Due to the reduced diameter of the pumping region 306 , (see FIGS. 3 and 5 ) the fluid insert 108 is able to move a short distance within the outer casing 106 . The movement of the fluid insert 108 forces retraction of the springs 115 into the pump 117 , so that, the tip 120 of the pump 117 is able to retract into the pump 107 . When the tip is retracted into the pump 107 , fluid material is withdrawn from the fluid material contained in the pump 107 and expelled through the opening 107 of the outer casing 106 . In its retraced position, the seal plug 132 abuts the outer edge 116 of the outer casing 106 , thereby eliminating the distance X present when the fluid dispenser 100 is in a stationary position. When the Force F is released, the fluid insert 108 will return to its fully extended position because the Force F that is transferred to the springs 115 is also released. This simultaneously causes the pump 117 to withdraw fluid material from the interior chamber 126 of the fluid insert body 128 , and store it in the pump 117 until another Force F is applied. It should be noted that although a user may continue to apply a Force F to the fluid insert 108 , no additional fluid material will be dispensed until the Force F is released, and a new Force F is applied. In this way, only predetermined amounts of fluid materials are dispensed at any one given time. When the fluid insert 108 is in its actuated or retracted position, the innermost end 129 (See FIG. 8 ) of the band 130 abuts the edge 302 (See FIG. 3 ) of the outer casing 106 . The notches 301 (See FIG. 9 ) will move along the tabs 300 (See FIG. 3 ) and the tip 120 of the pump 117 will be guided by the walls 600 (See FIG. 7 ) located on the interior 117 of the outer casing 106 . In this position, the tip 120 of the pump 118 is partially arranged within the pump 120 , and the distance X that is visible when the fluid insert sits in its stationary position (see FIG. 13 ) within the outer casing 106 is no longer visible. Referring to FIGS. 20-21 , the end cap 102 is shown. The end cap 102 helps to prevent fluid material contained within the fluid insert 108 from spoiling because it provides an additional outer seal to keep the fluid material fresh. The end cap 102 is circular in shape and designed to fit over the applicator 104 and connector 110 of the outer casing 106 . (See FIG. 1 .) The inner walls 250 of the end cap 102 fit snugly over the connector 110 of the outer casing 106 . Due to the minimal differences between the diameter of the end cap 102 and the diameter of the connector 110 , the end cap 102 can be securely positioned over the outer casing 106 so as to remain in place until it is desired to remove the end cap 102 from the outer casing 106 . As shown in FIG. 22 , an alternative embodiment of the end cap 102 ′ is shown. A declogger 252 is arranged at the center of the interior 250 ′ of the base 254 ′ of the end cap 102 ′. The declogger 252 is preferably in the shape of a cylinder that will fit within the opening 107 ′ of the outer casing 106 ′, but any shape of declogger that will fit within the opening 107 of the outer casing 106 will suffice. Placement of the declogger 252 within the end cap 102 ′ helps to prevent any clogging that may occur from fluid materials that dry and clog the opening 107 of the applicator 104 . An important feature of the present invention concerns the ability of the dispenser assembly 100 to be moved from a locked position to an unlocked position in order to avoid accidental discharge of the fluid material contained in the fluid insert 108 . The lock and unlock feature preferably operates by allowing the fluid insert 108 to rotate between a locked and unlocked position. When the dispenser assembly 100 is in an unlocked position, the dispenser assembly 100 is able to discharge fluids through the opening 107 of the outer casing 106 . This occurs when the tabs 300 located on the outer casing 106 are aligned with the notches 301 of the fluid insert 108 , so that the tabs 300 slide within the notches 301 . The first side 160 (see FIGS. 8-9 ) of the stop 111 will also be adjacent to the tab 300 (see FIG. 7 ). The stop 111 will prevent any additional rotation of the fluid insert 108 in the direction of the first side 160 of the stop 111 , to notify a user that the fluid insert 108 cannot be further rotated in that direction. As shown in FIG. 14 , directional arrows can be placed on the top of the seal plug 32 of the fluid insert to further provide visual instructions for the user to place the seal plug 132 into an open position. When the fluid insert 108 is rotated in the opposite direction, the fluid insert 108 moves from the unlocked position to a locked position. In this position, the tab 300 and notch 301 do not align. The tabs 300 will instead contact the inner casing outer edge 109 (See FIGS. 8-9 ), thereby preventing the fluid insert 108 from moving within the pumping region 306 of the outer casing 106 . The fluid insert 108 can only be rotated until the second side 109 of the stop 111 (see FIGS. 8-9 ) is adjacent the notch 300 ′. Thus, the fluid insert 108 is in a locked position whenever stop 11 of the fluid insert 108 is located between the notch 300 and notch 300 ′. In this locked position, fluid materials are unable to accidentally discharge from the fluid dispenser 100 . Due to the location of the tabs 300 and notches 301 on opposed sides of the outer casing 106 and fluid insert 108 , the fluid insert 108 moves from a closed position to an open position whenever the fluid insert 108 is rotated 180°. It should be appreciated, however, that the number of tabs and corresponding notches will determine the amount of rotation necessary to move the fluid insert 108 from a locked position to an unlocked position. The fluid dispenser assembly 100 according to the embodiments described herein is cost effective for the manufacturer, as well as the company desiring to purchase dispensers that can be used to sell their fluid products, such as a cosmetic company. It is comprised of few parts that can be “snapped” into place due to the various shapes of the components. This eliminates the need for the added costs of adhesives and the like, or the additional step of “screwing parts” together. The manufacturer therefore has few parts to produce and assemble, allowing the manufacturer to significantly cut production and materials costs. Due to the design of the dispenser assembly 100 , the manufacturer can then provide the dispenser assembly 100 almost fully assembled to a purchasing company desiring to solicit their fluid materials in a particular dispenser. The pump 107 and fluid insert body 108 can be preassembled into the outer casing 106 , and the end cap 102 can be placed over the applicator 104 of the outer casing 106 . The only part not assembled at that time is the seal plug 132 , which as discussed herein, is assembled after the filling process. The assembled parts of the dispenser assembly 100 are then placed onto a standard filling apparatus, making them immediately available for filling. The simple cylindrical shape of the applicator and the fact that there are no additional obstructions protruding from the dispenser assembly 100 , make the dispenser assembly 100 fully compatible with standard industrial filling machines. For example, the fluid dispenser 100 is fully compatible with a standard filling apparatus such as the NORDENMATIC 3003/5002 line, that is capable of filling 300-500 tubes per minute. The compatibility between the dispenser assembly 100 and a standard filling machine eliminates the need for purchasing additional parts to make the fluid dispenser compatible with the filing machine. Once the dispenser assemblies are positioned on the filling machine, the filling machine will dispense fluid material from the filling machine into the open end 127 of the fluid insert body 128 . Thereafter, the seal plug 132 can be snapped into the fluid insert by a standard capping machine, thereby fully completing the assembly of the fluid dispenser 100 . The capping process may also take place as part of the high speed filling process. The compatibility of the dispenser assembly 100 with standard filling apparatuses, combined with the relative ease of sealing the dispenser assembly 100 after it has been filled, are just some of the advantages of this embodiment of the present invention over the prior art. FIG. 23 shows an alternative embodiment of a fluid dispenser 200 . The outer casing 201 is curved in shape, so as to provide grips 210 for a user to hold the fluid dispenser 200 . The fluid insert 212 protrudes from the end 214 of the outer casing 200 , and is identical to the fluid insert shown in FIG. 1 . This alternative fluid dispenser 200 operates in substantially the same way as the fluid dispenser 100 previously discussed. A Force F is applied to the end of the fluid insert 212 , which causes actuation of the pump (not shown) contained in the fluid insert 212 . Fluid material is then dispersed from the fluid insert 212 to the opening (not shown) of the outer casing 201 . To seal the fluid dispenser 200 , a dispenser cap 216 fits over the outer casing 201 and prevents the fluid material contained in the fluid insert 212 from spoiling. It should be appreciated that the fluid insert 212 can consistently remain the same shape, while the outer casing 201 may take on any desired shape or form. This is advantageous for cosmetic companies and the like seeking to sell a customized dispenser. Although the invention herein has been described with reference to particular embodiments and preferred dimensions or ranges of measurements, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. Additionally, it is to be appreciated that the present invention may take on various alternative orientations. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.

The present invention is directed toward a cost effective instrument for storing a fluid material, and applying a predetermined amount of the fluid material to a surface. The instrument is comprised of few parts including an outer casing and a fluid insert, making the instrument cheaper to manufacture, and easy to assemble. The embodiments disclosed can be provided in a pre-assembled form to cosmetic companies and the like seeking to fill a dispenser with their fluid cosmetic products. The ability to provide dispensers in a pre-assembled form, combined with the compatibility of the fluid dispensers with industrial high speed filling machines, reduces the overall filling costs to the cosmetic company, as well as the cost to the consumer.

RELATED APPLICATIONS [0001] This application is a continuation-in-part of U.S. patent application Ser. No. 14/052,731 filed Oct. 12, 2013 that claims the benefit of U.S. Provisional Application No. 61/713,945 filed Oct. 15, 2012 entitled Method and Apparatus for Producing Sound Pulses within Bore Holes which is incorporated herein by reference in its entirety. This application further claims the benefit of U.S. Provisional Application No. 61/987,081 filed May 1, 2014 entitled, System and Method for Energizing an Impulsive Type Down-Hole Source which are each incorporated herein by reference in their entireties. FIELD OF THE INVENTION [0002] The present invention is related to a system and method for obtaining high quality seismic records from an impulse type sound source for geophysical studies of geological structures surrounding bore holes. The present invention is further related to a system and method of artificially pressurizing the bore hole and to adjusting and maintaining pressures within the bore hole to obtain sufficient sound output levels and high quality seismic records. BACKGROUND OF THE INVENTION [0003] Geophysical surveys provide a cross-sectional map of the geology below the surface of the earth. Using sound waves, the shape and character of the geology may be revealed to indicate pockets within the sedimentary layers where oil and gas may be trapped, indicating locations where exploratory wells may be drilled for further geological analysis. Geophysical studies between bore holes or between bore holes and the ground surface have been done in the past using small charges of explosive impulsive sources and vibratory sound sources, but none of these types of sound sources have proved to be either practical or robust enough to be used over extended periods of time. SUMMARY OF THE INVENTION [0004] A system and method of providing high quality seismic records from an impulse type of down-hole sound source designed to be robust as well as provide a practical tool to provide sound pulses for geophysical studies of the earth surrounding bore holes is here-with provided. The present invention further provides a system and method of obtaining seismic records using an impulsive sound source within a bore hole comprising the steps of artificially pressurizing the bore hole to obtain acceptable high quality seismic records. The present invention utilizes a free piston which is accelerated by the hydrostatic pressure of a fluid. Upon actuation of the free piston, the free piston moves through an isolated partially fluid filled piston chamber and strikes a sound transmitting anvil sending a sound pulse into an adjacent sound transmission chamber that is filled with light weight oil and surrounded by an elastomeric bladder. The sound pulse from the accelerating anvil moves the elastomeric bladder producing a sound wave that is emitted out through the fluid and ambient walls of the bore hole and into geological surrounding structures. In preparation for firing, an electric motor powered hydraulic pump, pumps hydraulic fluid to move a reset piston assembly to position a latching seal flange of the assembly into a receiving cup of a free piston. A check valve assembly within the flange provides for the evacuation of fluid within the receiving cup forming a vacuum seal that allows the reset piston assembly to draw the free piston through a high pressure fluid filled chamber and into a ready to fire position. The free piston is drawn to a stop point that breaks the vacuum and allows high pressure fluid within the chamber to rapidly accelerate the free piston against the anvil piston with the impulse providing the sound transmission. [0005] The impulsive sound source is designed in sections aligned end to end with a first cable termination module housing an umbilical cable and providing for the cable to be attached to and detached from the source. The cable is terminated at a two piece connector that has a first half portion within the upper module detachable from a second half portion that is mounted within the next module, an expansion chamber. The expansion chamber is enclosed with an elastomeric bladder to provide for changes in pressures within the source and assist in the absorption of vibrations as the source is fired. The expansion chamber serves as a reservoir for hydraulic fluid to operate the reset piston assembly. The expansion chamber also houses a set of power cables that extend through the chamber and are affixed to run an electric motor housed in the next module. The electric motor drives a hydraulic pump housed within a next module. The hydraulic pump takes fluid from and returns fluid to the reservoir of the expansion chamber and provides fluid to move the reset piston assembly that prepares the source for firing. The reset piston assembly module also houses the high pressure fluid implosion chamber for the free piston. The impact chamber is an open cylinder that houses the anvil and receives the fired free piston from the implosion chamber that strikes the anvil forcing the anvil a short distance into the sound transmission chamber transmitting the sound pulse to the elastomeric bladder that encloses the transmission chamber. The bladder propagates the sound through the fluid of the bore hole and the surrounding geological structure. [0006] The reversible three phase or DC motor is capable of high temperature operation and provides for the source to be successively fired as the motor is rotated in a first direction to supply hydraulic fluid to move the reset piston down to retrieve the free piston and an opposite direction to draw the free piston up to a ready to fire position with the rate of firing controlled by the speed of the motor. The motor direction is reversed using a relay switch that switches the power leads when the motor amperage peaks due to the latching seal flange bottoming out within the receiving cup in an extended position of the reset piston assembly or to switch directions when abutting a bulkhead of the reset piston assembly housing in a fully retracted position. In further embodiments, the electric motor may be controlled remotely to set the speed of the motor and firing rate. [0007] The modular design of the impulsive sound source provides for the top surface of the anvil and bottom surface of the free piston cylinder to be interchanged with anvils and free pistons of different shapes and sizes to change the characteristics of the sound pulse and seismic data. By varying the weight and/or stroke of the free piston and/or the anvil shape or other characteristics, the output pulse may be varied or tuned. For example, two flat shapes of the piston and anvil surfaces may produce the sharpest energy transition with the greatest amplitude and highest frequency upon impact of the free piston and the anvil piston. However, if the free piston shape is instead shaped as a conical point mating with the anvil having a conical hole, the frequency content would change as the conical point enters the conical hole producing a longer pulse with lower frequency content in the sound pulse with various shapes producing a range of amplitudes and frequencies. [0008] The impact chamber is further partially filled with fluid to create a cushion for the free piston and the anvil preventing the contact of metal on metal and absorbing vibrations within the source. The sound characteristics may be further changed by the compressibility and type of fluid used within the impact chamber. Fluids of different viscosity and compressibility may change compression characteristics of the fluid. For example, a more compressible fluid may slow the acceleration of the free piston and therefore produce a lower frequency pulse. The impulsive sound source may further be of any diameter and length necessary to accommodate the diameter of the bore hole and requirements of the geological survey. [0009] The present invention is further related to an impulsive sound source comprising an umbilical cable extending through a cylindrical housing; a hydraulic fluid reservoir formed within the housing and supplying a hydraulic pump; an electric motor powered from the umbilical cable and controlling the hydraulic pump; a hydraulic cylinder controlled by the hydraulic pump; a reset piston movable within a fluid filled piston chamber using the hydraulic cylinder, the reset piston having a flange movable within an implosion chamber; a free piston having an annular rim and cup within the implosion chamber; an anvil within an impact chamber adjacent the implosion chamber; an elastomeric bladder enclosing a fluid filled sound transmission chamber adjacent the impact chamber; and wherein the free piston is accelerated by hydrostatic pressure within the implosion chamber to strike the anvil and transmit a sound pulse through the sound transmission chamber and the elastomeric bladder. [0010] The impulsive sound source further comprises a latching seal assembly surrounding the reset piston flange, the flange having an inlet passage and check valve to evacuate fluid from the free piston cup and thereby latch the reset piston and free piston to draw the free piston to a ready to fire position. The difference in cross-sectional area of the reset piston flange and free piston annular rim provides the clamping force for the reset piston to latch to the free piston. The impulsive sound source may be repeatably fired by having the reset piston retract to an uppermost position causing the electric motor to rotate in a first direction to control the delivery of hydraulic fluid from the hydraulic pump to a first chamber and return hydraulic fluid to the reservoir from a second chamber and move the reset piston to the free piston and wherein the reset piston and free piston latch triggering the electric motor to reverse direction and the delivery of hydraulic fluid from the hydraulic pump is to the second chamber and return of hydraulic fluid to the reservoir is from the first chamber to move the reset piston and free piston to the uppermost position where the free piston is fired and the electric motor is triggered to rotate in the first direction. [0011] The impact chamber of the impulsive sound source may be partially filled with fluid and changing the viscosity and compressibility of the fluid within the impact chamber changes the characteristics of the sound pulse. In the impulsive sound source, the shape of a bottom surface of the free piston and the shape of the top surface of the anvil changes the characteristics of the sound pulse where as an example the top surface of the anvil may be recessed in shape and the shape of the free piston may be conical. The impulsive sound source may further have a dashpot in the anvil. The implosion chamber of the impulsive sound source may further comprise an elastomeric bladder to conform to fluid movements within the impulsive sound source. The reservoir of the impulsive sound source may further comprise an elastomeric bladder to conform to fluid movements within the impulsive sound source. Components of the impulsive sound source may be arranged in the order of an umbilical termination module on the top, an expansion chamber module beneath, next an electric motor housing module beneath, next a hydraulic pump module beneath, next an hydraulic cylinder module beneath, next a free piston implosion module beneath, next an impact chamber module beneath, and next a sound transmitting module beneath. [0012] The impulsive sound source may further comprise a manifold block adjacent to the hydraulic pump and the manifold block may house two pressure relief valves and two check valves. The reset piston of the impulsive sound source may be directly attached to a hydraulic piston rod on the opposite side of a hydraulic cylinder bulkhead. The sound transmitting anvil of the impulsive sound source may have fluid flow passages for fluid volume control. [0013] The present invention is further related to a method of generating a sound pulse within a bore hole through a manual or automated process, comprising the steps of extending an umbilical cable to support a cylindrical housing of a sound source; storing hydraulic fluid in a reservoir within the housing; supplying a hydraulic pump from the reservoir; controlling the hydraulic pump using an electric motor powered from the umbilical cable; filling a hydraulic cylinder using the hydraulic pump; moving a reset piston within a fluid filled implosion chamber using the hydraulic cylinder; seating the reset piston within a cup formed in the upper portion of a free piston; evacuating fluid from the cup forming a vacuum to draw the free piston using the reset piston to a ready to fire position; preventing travel of the free piston and pulling the reset piston from the cup thereby breaking the vacuum and accelerating the free piston to strike an anvil within an impact chamber to generate a sound pulse; transmitting the sound pulse through a fluid filled sound transmission chamber to an elastomeric bladder to propagate the pulse out and through the fluid filled bore hole and into the surrounding geological structures. [0014] The method of generating a sound pulse within a bore hole may further comprise the steps of changing the viscosity and compressibility of fluid within the impact chamber to change the characteristics of the sound pulse. The method of generating a sound pulse within a bore hole may also further comprise the steps of increasing or decreasing the weight of the free piston to change the characteristics of the sound pulse. The method of generating a sound pulse within a bore hole may also further comprise the steps of increasing or decreasing the length of the stroke of the free piston to change the characteristics of the sound pulse. The method of generating a sound pulse within a bore hole may also further comprise the step of shaping a top surface of the anvil and the bottom surface of the free piston in reciprocal shapes to change the characteristics of the sound pulse. The method of generating a sound pulse within a bore hole may also further comprise the steps of shaping the top surface of the anvil to be a recessed cone and shaping the bottom surface of the free piston to be conical in shape to change the characteristics of the sound pulse. The method of generating a sound pulse within a bore hole may also further comprise the steps of transmitting a sound pulse wherein the free piston and anvil having flat surfaces; and collecting geological survey data; transmitting a sound pulse wherein the free piston having a conical shape and the anvil having a recess; collecting geological survey data; and combining the geological survey data acquired. [0015] The method of generating a sound pulse within a bore hole may also further comprise the step of forming a dashpot in the anvil. The method of generating a sound pulse within a bore hole may also further comprise the step of enclosing the implosion chamber with an elastomeric bladder. The method of generating a sound pulse within a bore hole may also further comprise the step of enclosing the reservoir with an elastomeric bladder to form an expansion chamber. The method of generating a sound pulse within a bore hole may also further comprise the step forming the free piston with an annular rim. [0016] The present invention is further related to a system and method of obtaining acceptable high quality seismic records by adjusting and maintaining pressures within a bore hole that may be similar to initial pressures from the first acquisition data in the survey or to desired pressures based on the fluid of the bore hole or the intensity and characteristics of the recorded seismic data. In performing a seismic survey, the impulsive sound source may be lowered to a position within a bore hole and fired to acquire the seismic records. The impulsive sound source may then be moved set distances and fired to acquire seismic data within the prescribed region of the survey. Each time the impulsive sound source is moved, pressures surrounding the source change resulting in changes to the intensity and characteristics of the seismic data. [0017] The present invention is related to a method of obtaining seismic records using an impulsive sound source within a bore hole comprising the steps of lowering an impulsive sound source to a desired depth within a bore hole to begin a seismic survey; measuring pressure readings within the bore hole to determine an initial pressure; adjusting the supply of gas or fluid to the bore hole to adjust the pressure within the bore hole based on the initial pressure and current pressure readings; firing the impulsive sound source; and acquiring seismic records. The method of obtaining seismic records using an impulsive sound source within a bore hole further comprising the step of adjusting the pressure within the bore hole to the initial pressure. The method is further related to the steps of determining the intensity and characteristics of the seismic records. The method further comprises the steps of adjusting the supply of gas or fluid to the bore hole to adjust the pressure within the bore hole based on the determined intensity and characteristics of the seismic records. [0018] The method further comprises the steps of raising the impulsive sound source to a new depth within the bore hole; measuring pressure readings within the bore hole at the new depth; adjusting the supply of gas or fluid to the bore hole to adjust the pressure within the bore hole to the initial pressure readings. The method further comprises the steps of raising the impulsive sound source to a new depth within the bore hole; measuring pressure readings within the bore hole at the new depth; adjusting the supply of gas or fluid to the bore hole to adjust the pressure within the bore hole to a desired pressure based on the initial and current pressure readings. The method further comprises the steps of moving the impulsive sound source to another depth within the bore hole; measuring pressure readings within the bore hole; firing the impulsive sound source within the bore hole; determining the intensity and character of the seismic records; adjusting the supply of gas or fluid to the bore hole to adjust the pressure within the bore hole based on the initial and current pressure readings and the intensity and characteristics of the seismic records. The method further comprises the steps of simultaneously moving the impulsive sound source while firing the impulsive sound source within the bore hole while measuring pressure readings within the bore hole while determining the intensity and characteristics of the seismic records and adjusting the supply of gas or fluid to the bore hole to adjust the pressure within the bore hole based on the initial and current pressure readings and the intensity and characteristics of the seismic records. [0019] The present invention is further related to a method of obtaining seismic records using an impulsive sound source within a bore hole comprising the steps of artificially pressurizing the bore hole to obtain enough pressure to operate the sound source to sufficient sound output levels to obtain acceptable high quality seismic records. In the method, the pressure levels are changed within the bore hole as the sound source is moved within the bore hole in order to adjust the pressure within the bore hole to a desired level. The present invention is further related to a method of moving an impulsive sound source up or down within a fluid filled bore hole, adjusting pressures within the bore hole and firing the source at a constant fluid pressure surrounding the source. [0020] The present invention is further related to a system for adjusting and maintaining pressure within a bore hole in order to obtain consistent quality seismic records using an impulsive sound source comprising an impulsive sound source; an umbilical cable for lowering the impulsive sound source to a desired depth within a bore hole to begin a seismic survey; a pressure sensor measuring readings within the bore hole; a gas or fluid pressure source; a pressure regulator adjusting the supply from the pressure source of gas or fluid to the bore hole to adjust the pressure within the bore hole based on an initial and current pressure readings; a controller for firing the impulsive sound source. The system for adjusting and maintaining pressure within a bore hole in order to obtain acceptable quality seismic records wherein the initial pressure is a pressure reading taken at an initial depth at the beginning of a seismic survey. The system for adjusting and maintaining pressure within a bore hole in order to obtain acceptable quality seismic records further comprises a computer processor for determining the intensity and characteristics of the seismic records from the firing of the impulsive source. In using the system for adjusting and maintaining pressure within a bore hole in order to obtain acceptable quality seismic records using an impulsive sound source, the adjustment of gas and/or fluid from the pressure source using the pressure regulator may be based on the determined intensity and characteristics of the seismic records. The impulsive sound source may then be moved to a new depth within the bore hole using the umbilical cable of the pressure source and using the pressure regulator of the system the supply of gas or fluid to the bore hole may be adjusted to the initial pressure or to a desired pressure at the new depth. Using the computer processor, the system for maintaining pressure within a bore hole in order to obtain acceptable quality seismic records using an impulsive sound source, the pressure regulator may adjust the supply of gas or fluid to the bore hole to the initial pressure or a desired pressure simultaneously while the impulsive sound source is moving and firing based on the initial and current pressure readings and the intensity and characteristics of the seismic records. The pressure within the bore hole may be adjusted automatically using the computer processor or by using a manually controlled pressure regulator or a manually operated fluid control valve. [0021] The present invention is related to an impulsive sound source for obtaining seismic records within a bore hole, comprising a hydraulic pump; a reset piston; a free piston; a movable anvil; and wherein the free piston is accelerated by hydrostatic pressure to strike the movable anvil and transmit a sound pulse through a bore hole to obtain seismic records. The impulsive sound source may comprise an umbilical cable. The impulsive sound source may comprise a hydraulic fluid reservoir. The impulsive sound source may comprise at least one elastomeric bladder. The free piston of the impulsive sound source may have an annular rim and cup. The reset piston may have a latching seal and check valves to expel fluid from the free piston cup to latch the reset piston and free piston. The impulsive sound source may comprise an electric motor and may be repeatably fired by having the reset piston move to a retracted position causing the electric motor to rotate in a first direction to control the hydraulic pump to move the reset piston to the free piston; and the reset piston and the free piston latch triggering the electric motor to reverse direction and move the reset piston and free piston to the retracted position to fire the free piston and trigger the electric motor to rotate in the first direction. The characteristics of the sound pulse of the impulsive sound source may be changed by changing the weight of the free piston. The characteristics of the sound pulse of the impulsive sound source may be changed by changing the stroke of the free piston. [0022] The present invention is further related to an impulsive sound source, comprising an impulsive sound source comprising modules, the modules comprising an umbilical termination module; an expansion chamber module; an electric motor housing module; a hydraulic pump module; a hydraulic cylinder module; a free piston implosion module; an impact chamber module; and a sound transmitting module. [0023] The components of the impulsive sound source are arranged in the order of the umbilical termination module on the top, the expansion chamber module beneath, next the electric motor housing module beneath, next the hydraulic pump module beneath, next the hydraulic cylinder module beneath, next the free piston implosion module beneath, next the impact chamber module beneath, and next the sound transmitting module beneath. [0024] The present invention is further directed to a method of obtaining seismic records within a bore hole, comprising the steps of delivering hydraulic fluid to move a reset piston to a free piston; latching the reset piston to the free piston; moving the reset piston and free piston to a ready to fire position; accelerating the free piston using hydrostatic pressure to strike a movable anvil to generate a sound pulse; transmitting the sound pulse through a bore hole to obtain seismic records. The method of obtaining seismic records within a bore hole comprising the steps of repeatedly firing the sound source comprising the steps of controlling the delivery of hydraulic fluid using an electric motor; moving the reset piston to a retracted position causing the electric motor to rotate in a first direction to deliver hydraulic fluid to move the reset piston to the free piston; latching the reset piston to the free piston causing the electric motor to reverse direction to deliver hydraulic fluid to move the reset piston and free piston to the retracted position to fire the free piston and trigger the electric motor to rotate in the first direction. [0025] The present invention is further related to a method of obtaining seismic records using an impulsive sound source within a bore hole comprising the steps of moving an impulsive sound source within a bore hole; adjusting pressures within the bore hole; firing the impulsive sound at an adjusted pressure surrounding the impulsive sound source; and acquiring seismic records. The method of obtaining seismic records using an impulsive sound source within a bore hole may further comprise the steps of measuring pressure readings within the bore hole at the a first depth to obtain an initial pressure; moving the impulsive sound source to a new depth within the bore hole; measuring pressure readings within the bore hole at the new depth; adjusting pressure within the bore hole to the initial pressure. The method of obtaining seismic records using an impulsive sound source within a bore hole may further comprise the steps of moving the impulsive sound source to a new depth within the bore hole; measuring pressure readings within the bore hole at the new depth; adjusting pressure within the bore hole to a desired pressure. The method of obtaining seismic records using an impulsive sound source within a bore hole may further comprise the steps of determining the intensity and characteristics of the seismic records. The method of obtaining seismic records using an impulsive sound source within a bore hole may further comprise the steps of adjusting the pressure within the bore hole based on a determined intensity and characteristics of the seismic records. The method of obtaining seismic records using an impulsive sound source within a bore hole may further comprising the steps of moving the impulsive sound source to another depth within the bore hole; measuring pressure readings within the bore hole; firing the impulsive sound source within the bore hole; determining the intensity and characteristics of the seismic records; adjusting the pressure within the bore hole based on pressure readings and the intensity and characteristics of the seismic records. The method of obtaining seismic records using an impulsive sound source within a bore hole may comprise the steps of simultaneously moving the impulsive sound source while firing the impulsive sound source within the bore hole while measuring pressure readings within the bore hole while determining the intensity and characteristics of the seismic records; and adjusting the pressure within the bore hole based on the pressure readings and the intensity and characteristics of the seismic records. The method of obtaining seismic records using an impulsive sound source within a bore hole may comprise the steps of artificially pressurizing the bore hole to obtain enough pressure to operate the impulsive sound source to sufficient sound output levels to obtain consistent quality seismic records. The pressure levels within the bore hole in the method of obtaining seismic records may be adjusted while the sound source is moving within the bore hole in order to keep the pressure within the bore hole at a desired level. [0026] The present invention is further related to a system for adjusting and maintaining pressure within a bore hole in order to obtain acceptable quality seismic records using an impulsive sound source comprising an impulsive sound source having at least one pressure sensor; a pressure source; and wherein the pressure source adjusts the pressure within the bore hole based on initial and current pressure readings from the at least one pressure sensor. The initial pressure in the system may be a pressure reading taken at an initial depth at the beginning of a seismic survey and current pressure readings are pressure readings taken during the seismic survey. The system for adjusting and maintaining pressure within a bore hole in order to obtain acceptable quality seismic records using an impulsive sound source may further comprise a computer processor for determining the intensity and characteristics of the seismic records from the firing of the impulsive source. The adjustment of pressure within the bore hole may be based on a determined intensity and characteristics of the seismic records. The impulsive sound source may be moved to a new depth within the bore hole and the pressure source may adjust the pressure within the bore hole to the initial pressure at the new depth. The impulsive sound source may be moved to a new depth within the bore hole and the pressure source may adjust the pressure within the bore hole to a desired pressure at the new depth. In using the computer processor, the pressure source may adjust the pressure within the bore hole at the current depth of the impulsive sound source simultaneously while the impulsive sound source is moving and firing based on one of at least the initial and current pressure readings and the intensity and characteristics of the seismic records. [0027] These and other features, advantages and improvements according to this invention will be better understood by reference to the following detailed description and accompanying drawings. While references may be made to upper, lower, vertical and horizontal, these terms are used merely to describe the relationship of components and not to limit the operation of the present invention to any one orientation. BRIEF DESCRIPTION OF THE DRAWINGS [0028] Several embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings in which: [0029] FIG. 1A is a cross-sectional diagram of a first portion of a first embodiment of the impulsive sound source in an embodiment of the present invention; [0030] FIG. 1B is a continuation of the cross-sectional diagram of FIG. 1A as a second portion of a first embodiment of the impulsive sound source of the present invention; [0031] FIG. 2A is a cross-sectional diagram of a first portion of the first embodiment of the impulsive sound source of the present invention; [0032] FIG. 2B is a continuation of the cross-sectional diagram of FIG. 2A as a second portion of the first embodiment of the impulsive sound source of the present invention; [0033] FIG. 3 is a cross sectional diagram of an embodiment of a cable termination of module A of the first embodiment of the impulsive sound source of the present invention; [0034] FIG. 4 is a cross sectional diagram of an embodiment of an expansion chamber of module B of the first embodiment of the impulsive sound source of the present invention; [0035] FIG. 5 is a cross sectional diagram of an embodiment of an electric motor of module C of the first embodiment of the impulsive sound source of the present invention; [0036] FIG. 6 is a cross sectional diagram of an embodiment of a hydraulic fluid pump of module D of the first embodiment of the impulsive sound source of the present invention; [0037] FIG. 7A is a cross sectional diagram of an embodiment of a reset piston assembly and high pressure free piston chamber of module E of the first embodiment of the impulsive sound source of the present invention in a ready to fire; [0038] FIG. 7B is a cross sectional diagram of the embodiment of the reset piston assembly and free piston chamber of module E of the first embodiment of the impulsive sound source of the present invention in a fired position; [0039] FIG. 7C is a cross sectional diagram of an embodiment of the reset piston assembly and free piston chamber of module E of the first embodiment of the impulsive sound source of the present invention in an extension of the reset piston assembly to prepare the source for firing; [0040] FIG. 7D is a top view cross section showing an embodiment of the communication ports in the implosion chamber of module E in a first embodiment of the impulsive sound source of the present invention; [0041] FIG. 7E is a cross sectional diagram of an embodiment of a latching seal flange of the reset piston assembly of module E of the first embodiment of the impulsive sound source of the present invention; [0042] FIG. 8 is a cross sectional diagram of an embodiment of an impact chamber of module F of the first embodiment of the impulsive sound source of the present invention; [0043] FIG. 9 is a cross sectional diagram is a further embodiment of the free piston and anvil of the impact chamber of module F of the first embodiment of the impulsive sound source of the present invention; [0044] FIG. 10A is a cross sectional diagram of an embodiment of a sound transmission chamber of module G of the first embodiment of the impulsive sound source of the present invention; and [0045] FIG. 10B is a top view cross section showing an embodiment of the communication ports in the sound transmission chamber of module G in a first embodiment of the impulsive sound source of the present invention; [0046] FIG. 11A is a cross-sectional diagram of an embodiment of a first portion of the impulsive sound source within a bore hole with an embodiment of a pressure regulating system of the present invention to adjust pressures within the bore hole in an embodiment of the present invention; and [0047] FIG. 11B is a continuation of the cross-sectional diagram of FIG. 11A of an embodiment of a second portion of the impulsive sound source within a bore hole in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0048] The present invention is an impulsive type sound source for creating sound pulses which can be used for seismic surveys between liquid filled bore holes in the ground such as water wells, oil wells and/or bore holes for geological studies. The present invention is further related to a system and method of artificially pressurizing the bore hole to obtain adequate and consistent pressures to operate the sound source to sufficient sound output levels to obtain acceptable high quality seismic records. [0049] The present invention provides a sleek modular design of an impulsive sound source 1 to make the system easier for transportation and insertion of the source into wells and bore holes for seismic analysis deep within the ground. The impulsive sound source 1 may be of any diameter and dimension suitable for the requirements of a geological survey with components of acceptable materials to withstand the high temperatures and pressures within water wells, oil wells and/or the bore holes used for geological studies. In a first embodiment, the impulsive sound source 1 is constructed with the series of modules as shown in FIGS. 1A and 1B with each of the modules A-G fixed end to end to one another along axis X using clamping rings and a series of bolt circles. Module A is the umbilical cable termination that as shown in FIGS. 2A and 2B has a housing 3 where the umbilical cable 2 aligns through the center of the housing and along axis X. The housing 3 may be of any shape, dimension or design with an upper termination head that is dependent on the size, design and construction of the umbilical cable 2 . The umbilical cable 2 carries the weight of the source 1 as well as shields and surrounds the electric cables for power to the motor, and for electrical and/or optical cables for control and sensors as required within the source 1 such as sensors to determine the instant of firing, the pressure, the temperature and structural conditions within the source and within the bore hole. [0050] As shown in FIG. 3 , the connector 5 of module A provides a wire block 6 that distributes the electrical power, sensor and control cables throughout the source 1 . Module A is attached to module B using a series of bolts 7 and a stainless steel clamping ring 4 positioned around the lower end of the cylindrical housing 3 . Each of the upper and lower edges of the clamping ring 4 has a rim 8 extending completely around the ring 4 forming a channel 10 along a middle portion of the ring 4 . The housing 3 and the rim 8 of the ring 4 may have a series of bolt holes 9 that are evenly spaced around the outer edge of the cylinder to accept the bolts 7 that secure the ring 4 to the housing 3 . A groove 12 may be formed in the housing 3 to accept the rim 8 of the ring 4 . The shoulder 14 forming the groove 12 may extend at a distance from axis X that is greater than a tubular center casing 15 that mates and aligns with the housing of module B. The tubular casing 15 formed on the base of the housing 3 is of a slightly smaller diameter than the diameter of the cylindrical housing 16 of module B. The housing 16 of module B, in this embodiment, is similarly formed with a shoulder 14 and groove 12 to provide for the lower rim 8 of the clamping ring 4 to lock around the shoulders 14 and secure the modules together. An index pin 18 may provide for the proper alignment and orientation of the modules with respect to one another. As described herein, heat resistant seal and bearing assemblies 20 made of viton or other plastic materials typically used in high pressure fluid applications are installed at the tubular casing 15 and at other connections in the housing and at each fluid path throughout the source to prevent leakage of hydraulic fluid and to properly secure and seal all high pressure connections. [0051] Module B, as shown in FIG. 4 , is an expansion chamber that is formed with a housing surrounded by an elastomeric bladder 21 . The second half of the cable distribution connector 5 is a connector receptor 22 that is positioned at the top of the electric cable and fluid flow passage 24 that is formed through the center of the housing 16 . The cable distribution connector 5 provides for the cable termination of module A to be disconnected from the rest of the impulsive sound source for transportation of the source separate from the umbilical cable 2 . The power cables 26 are properly shielded and extend down and through the fluid flow passage 24 to reach the motor cable connector 32 at the top of the motor 34 in module C. In a first embodiment, a combination time break pressure and temperature transducer 33 used to detect the firing of the source as well as monitor and transmit pressure and temperature is installed at the top of the fluid flow passage 24 . Other sensors may be positioned throughout the source 1 to determine temperature and pressure as well as monitor and collect system operational parameters and other information. Module B also has openings 31 through the housing 16 to allow fluid communication from the flow passage 24 to the expansion chamber bladder 21 . The flow passage 24 and expansion chamber 28 are filled with high temperature resistant hydraulic fluid to serve as a reservoir for the hydraulic pump 52 of module D of the source 1 . The bladder 21 is secured to the housing 16 using band clamps 36 that surround the housing 16 and affix the bladder 21 at only the upper and lower portion of the housing 16 to allow for the middle of the bladder 21 to expand as pressure changes occur within the flow passage 24 and other modules of the source 1 . A filler port 38 is provided to fill the flow passage 24 . A vent 30 may be provided along the filler port passageway 29 . A fluid passageway 40 is also provided at the base of module B to provide for communication of fluid between the flow passage 24 and the electric motor 34 of module C. [0052] A housing 44 , as shown in FIG. 5 , surrounds the electrical motor 34 and an annular fluid flow compartment 42 is formed between the housing 44 and the module C outer housing 45 . The compartment 42 is filled with the system hydraulic fluid from the upper passageway 40 from module B to help maintain the motor 34 at acceptable operational temperatures. The upper passageway 40 also provides for fluid to flow from the compartment 42 back through to the expansion chamber flow passage 24 of module B as the source is fired and pressures change within the source. As temperature and pressure increase or decrease within the source and fluid moves through the hydraulic system, the expansion bladder 21 expands or contracts to prevent damage to components within the source due to fluid fluctuations. At the base of the enclosure 44 a flow passage 47 connects the reservoir of Module B to the manifold block 54 of module D and a rubber or other durable shock absorbing material cushion mount 48 is placed to help isolate the motor 34 from accelerations caused by the motions of the free piston 43 . The motor 34 is a reversible three phase or DC motor capable of high temperature operation. The motor housing 44 and other structural components of the source 1 may be of stainless steel or other comparable materials that are capable of sustaining the load and pressures of the firing of the source 1 and bore hole environment. At the base of the motor 34 , the shaft 49 of the electric motor 34 extends along axis X into module D to operate the hydraulic fluid pump 52 . The shaft 49 is aligned through the manifold block 54 and is affixed to the hydraulic pump 52 using a flexible coupling 56 as shown in FIG. 6 . [0053] The manifold block 54 is in the upper portion of module D and contains two check valves 58 and two pressure relief valves 60 for supplying the bi-directional hydraulic pump 52 with hydraulic fluid and for setting the maximum pressure at which the hydraulic system may operate. The manifold block 54 has fluid by-pass passages 62 that connect the pump 52 to the pressure relief valves 60 and bores 64 that communicate with fluid by-pass tubes 66 for delivering hydraulic fluid to the reset piston assembly chambers 63 and 65 of module E. The by-pass tubes 66 extend from an upper portion 67 of the housing 68 of module D to a lower portion 69 that forms a shoulder for the tubing connection. 0 -rings 61 are rabbited into recesses within the upper and lower housing 68 and 69 and each end of the by-pass tubes 66 are installed. This design feature provides easy access to the tubing 66 for repair. The upper surface 70 of the lower housing portion 69 forms a seat for bolts 7 to be inserted through bolt holes that are evenly spaced around the cylindrical housing for attachment of module D to module E. [0054] As the motor shaft 49 rotates in one direction, fluid is delivered to one by-pass passage 62 and one by-pass tube 66 and fluid is returned through the other by-pass tube 66 and by-pass passage 62 thereby simultaneously filling one and evacuating the other of the reset piston chambers 63 and 65 to extend or retract the reset piston assembly of module E. The check valves 58 direct fluid flow based on the rotational direction of the motor 34 . The relief valves 60 provide for the release of fluid back to the reservoir of module B to prevent over pressuring the system as the reset piston assembly reaches a full point of extension and bottoms out in the receiving cup 130 of the free piston 110 or full retraction at an upper most point with the motor continuing to run in one direction until a peak in amperage triggers a relay switch (not shown) to change the direction of flow. [0055] As shown in FIG. 6 , the rod 72 of the reset piston assembly extends into a cavity 74 formed by the housing 68 of module D. In order to slide smoothly a bearing and seal assembly is installed within bulkhead 75 . The bearing and seal assembly includes a seal 71 a bearing 73 and a backup ring 78 positioned to protect the seal 71 from extrusion. To secure the bearing and seal assembly in place a retainer ring 82 is installed between a preformed edge 77 at the base of the housing 68 and a ledge formed at the upper surface 79 of the upper housing 80 of module E. The seal 71 prevents fluid leakage from chamber 63 into cavity 74 as chamber 63 is pressurized. [0056] The reset piston 84 separates chambers 63 and 65 and is positioned along the piston rod 72 using a cylindrical sheath 83 and cap nut 85 that is tightened to hold the reset piston 84 in place along the rod 72 . The sheath 83 is set at a thickness t that when combined with the upper rod diameter d is equal to the lower rod diameter D below the piston 84 in order to maintain an equal volume in the actuation chamber 63 and refraction chamber 65 above and below the piston 84 . Hydraulic fluid from the hydraulic pump 52 is fed to and returned from the actuation chamber 63 through actuation feed bore 87 . Hydraulic fluid is fed to and returned from the retraction chamber 65 through feed bore 89 . A seal gland and ring bearing assembly 86 is affixed to the outer diameter of the reset piston 84 to seal and further assist in the reduction of friction as shown in FIG. 7A . The housing 80 of module E encloses the reset piston actuation chamber 63 and retraction chamber 65 with bulkhead 76 forming the base of the refraction chamber 65 . The housing 80 is enclosed by an elastomeric bladder 102 forming the high pressure fluid implosion chamber 100 for the free piston 110 . The free piston 110 may be hollow to reduce the weight of the free piston 110 and the overall weight of the source 1 . [0057] The bladder 102 is affixed to the housing at each end of the module using band clamps 36 . The chamber 100 is sealed using a seal gland and ring bearing assembly 94 at bulkhead 76 that provides for reduced friction allowing the piston rod 72 to move smoothly between the reset piston chamber and implosion chamber. For the communication of fluid to and from the actuation and retraction feed lines 87 and 89 bores may be drilled through the housing and resealed with a brazed plug 96 . A fluid fill plug 98 that is for example 90 degrees away from the actuation and retraction feed lines 87 and 89 is provided to fill the implosion chamber 100 with hydraulic fluid. [0058] The housing 80 of the implosion chamber 100 may be tapered at either end to provide support structures for the attachment of bolts 7 to connect module D at the upper support structure 104 and to connect module F at the lower support structure 106 along the axis X. A seal gland ring bearing assembly 112 is installed at the lower support structure 106 to seal the implosion chambers and reduce friction to allow the free piston 110 to move smoothly within the impact chamber 120 of module F. The module F housing 118 surrounds the free piston 110 to form the impact chamber 120 . Additional seals 20 are installed between the support bulkhead 118 and lower structural support 106 of housing 80 to prevent leakage. A fluid fill plug 128 as shown extends from the impact chamber perpendicularly to axis X and through the support bulkhead 118 to fill the impact chamber 120 to an appropriate fluid level denoted as fin FIG. 7A . [0059] As shown in FIG. 7A , the piston rod 72 extends out and through the actuation and retraction chambers 63 and 65 and the chamber bulkhead 76 . Attached to the end of the reset piston rod 72 is the reset piston latching seal assembly 123 that using a vacuum seal retains and draws the free piston 110 to a ready to fire position at an uppermost point within the implosion chamber 100 . At the highest retraction point of the reset piston 84 , the upper circular surface 151 of the receiving cup 130 strikes a shoulder 152 of the housing 80 that pulls the latching seal 146 out of the cup 130 breaking the vacuum seal and providing for high pressure fluid to flow past the latching seal 146 to rapidly accelerate the free piston through the chamber 100 to contact the anvil 160 within the impact chamber 120 transmitting the sound pulse as shown in FIG. 7B . A cross-sectional top view of the housing 80 showing the central portion of the implosion chamber 100 and the ports 90 that provide communication between the chamber 100 and the elastomeric bladder 102 is shown in FIG. 7C . [0060] The source 1 is prepared for firing by filling the actuation reset piston chamber 63 with pumped pressurized hydraulic fluid to force the reset piston 84 and the latching seal assembly 123 from the upper retraction position after firing down and into the receiver cup 130 of the free piston 110 at the base of the implosion chamber 100 , as shown in FIG. 7D . The latching seal assembly 123 plugs into the receiver cup 130 formed in the upper portion at the top of the free piston 110 , and is retained within the receiver cup 130 due to the evacuation of fluid that is trapped within the space between the bottom cylindrical surface 145 of the reset piston flange 138 that includes the reset piston latching seal assembly 123 and the upper cylindrical surface 148 of the cup 130 . The fluid within this space is purged out through a passageway 132 forcing check valve 134 to open and release the evacuated fluid into the implosion chamber 100 through the check valve outlet 135 . The evacuated space forms a vacuum to effectively lock the latching seal assembly flange 138 and free piston 110 together. Hydraulic fluid is then simultaneously removed from the actuation chamber 63 and fed to the retraction chamber 65 to draw the free piston 110 up to an uppermost retraction point in the implosion chamber 100 . [0061] The latching seal assembly 123 , as shown in FIG. 7E , has a high pressure latching seal ring 146 that surrounds the flange 138 . The flange 138 has a diameter with a very close tolerance to and only slightly smaller than the diameter of the receiving cup 130 with the latching seal ring 146 seated within a groove formed around the outer diameter of the flange 138 and extending out beyond the edge 142 of the outer diameter of the flange 138 . In a first embodiment, the latching seal 146 is retained within this groove in the flange a hooked sealing surface 141 and using a seal retainer ring 143 with flat head screws 144 that may be inserted through the base 145 of the flange 138 and be countersunk to maintain a smooth surface of the base 145 to mate with the smooth surface 148 of the receiving cup 130 . Alternatively, the retaining ring 143 and screws 144 may be inserted through the upper surface 147 of the flange 138 to retain the latching seal 146 . The retainer ring 143 may have a similar hooked surface 139 to retain the seal 146 . Check valve 134 is mounted within the center and flush to the base 145 of the flange 138 by inserting a spanner wrench in slots 133 on either side of a central fluid passageway 132 . The outlet port 135 of the check valve 134 communicates with the implosion chamber 100 and provides for fluid in the space between the base 145 of the reset piston assembly flange 138 and the inner cylindrical surface 148 of the receiving cup 130 to be evacuated through the passageway 132 and open check valve 134 to create the vacuum seal that retains and draws the free piston 110 into the ready to fire position. A pressure relief outlet 92 may be formed through the reset piston assembly housing 80 . [0062] As an example, if all or nearly all of the fluid has been purged out of the space between the bottom surface 145 of the piston flange 138 and the inner surface 148 of the free piston cup 130 through the check valve 134 and given that the sealing diameter at the inside diameter ID of the receiving cup 130 of the free piston 110 is 8.9 cm (3.5 inches) and the diameter of the portion of the reset piston assembly flange 138 within the receiving cup 130 is 7.6 cm (3.0 inches), the difference in effective cross sectional area at the annular rim 149 of the receiving cup 130 is 6.5 cm 2 (2.56 square inches). Therefore, if the fluid pressure within the implosion chamber 100 is 20.6 MPa (3000 psi) then as the reset piston assembly flange 138 moves upward compressing the fluid within the implosion chamber 100 , the 6.5 cm 2 (2.56 square inch) difference in area produces a clamping force approaching 34.2 kN (7680 pounds of force) between the flat surfaces. This clamping force provides for the reset piston assembly to draw the free piston 100 to the full retraction point of the reset piston assembly. At the top of the retraction stroke of the reset piston 84 , the upper edge 151 of the receiving cup 130 of the free piston 110 is stopped against the bottom side of a shoulder 152 formed in the implosion chamber housing 80 and the latching seal assembly flange 138 begins to pull out of the receiving cup 130 . The expanded diameter of the latching seal 146 is pulled past a radius 154 formed in the vertical wall of the cup 130 releasing the vacuum and allowing fluid within the chamber 100 to flow past the latching seal 146 and fill the evacuated space between the upper and lower surfaces 145 and 148 accelerating the free piston 110 rapidly towards the impact chamber 120 . [0063] The impact chamber 120 , as shown in FIG. 8 , is partially filled with fluid to cushion the impact between the metal impact surface or face 162 of the free piston 110 and the anvil impact face 164 . The compressibility and viscosity of the fluid within the impact chamber 120 and the shape of the impact surface 162 and anvil face 164 all contribute to the quality and characteristics of the sound produced by the impulsive sound source 1 . Upon impact, the anvil piston 160 within the cylindrical support bulkhead 118 of module F and partially into an upper portion 172 of the sound transmission chamber 170 of module G. The support bulkhead 118 includes two bolting flanges 124 and 125 that extend laterally to provide bolt holes that are evenly spaced around the circular upper flange 124 attaching module E to module F and the circular lower flange 125 attaching module F to module G. [0064] A dashpot nose 166 is formed at the cylindrical base 168 of the anvil piston 160 . The cushion profile of the dashpot 166 is formed to act as a damper to absorb the remaining energy of the anvil 160 as it stops moving at the bottom of its impulse stroke. A seal and bearing assembly 178 is installed on the anvil piston 160 to reduce friction and a ring seal 179 is installed on the bulkhead 118 to prevent fluid flow between the impact chamber 120 and sound transmission chamber 170 . [0065] After firing, the impact chamber fluid is forced through a channel 180 formed through the anvil piston 160 and into a by-pass passageway 181 and into the space 182 within the impact chamber 120 created by the movement of the anvil piston 160 of module F. In drawing the free piston 110 up to the reset position for firing, fluid is drawn from the space 182 and up through the channel creating a vacuum and drawing the lower anvil piston 160 up and into the impact position for firing. The source 1 may be of any acceptable shape and dimension to accommodate the shape and dimensions of the bore hole being surveyed. As shown in FIG. 9 , the free piston 110 may be shaped as a conical point 163 and the anvil may have a cylindrical opening 177 that would cause the frequency content to change as the conical point 163 enters the opening 177 producing a longer pulse with lower frequency content in the sound pulse. The free piston 110 and anvil may be formed in various shapes to produce a range of amplitudes and frequencies. Also by varying the weight and stroke of the free piston and/or anvil, the shape, intensity, and characteristics of the output pulse may be varied or tuned. [0066] A fill valve 184 and passage 186 is provided for module G to fill and adjust the fluid within the sound transmission chamber 170 . A bladder 188 is affixed to the upper portion and lower portion of the sound transmission housing 176 as shown in FIG. 10A using band clamps 36 . Any number of ports 190 to transfer fluid from the sound transmission chamber 170 to the bladder 188 may be formed within the sound transmission chamber housing 176 with the number and dimensions dependent on the requirements of the geological survey. As noted, because of the modularity of the source 1 , module G may be replaced with a sound transmission chamber having more or less than the four ports shown from the top view of the sound transmission chamber in FIG. 10B . A time break transducer or other sensors 33 may be installed in the sound transmission chamber 170 to detect the firing of the source or pressures and temperatures within the source 1 . In a first embodiment, the end 194 of module G may be conically in shape to prevent the source from being held or damaged on ledges within the bore hole as the source is inserted and hung from the umbilical cable 2 . [0067] In operation, the source 1 in its ready to fire position is shown in FIG. 7A , in its fired position is shown in FIG. 7B and in its reset position is shown in FIG. 7D being picked up by the reset piston latching seal assembly 123 . As the latching seal assembly flange 138 plugs into the receiving cup 130 at the top of the free piston 110 , the latching seal 146 seals and slides within the bore of the cup 130 . Fluid within the cup 130 escapes out through the check valve 134 forming a partial vacuum with the clamping force of the high pressure fluid within the implosion chamber 100 holding the reset piston latching seal assembly 123 and the interior surface 148 of the cup portion 130 together to draw the free piston 110 to the refraction point where the upper edge 151 of the free piston 110 is stopped against the shoulder 152 formed within the reset piston assembly housing 80 . The latching seal assembly flange 138 is partially pulled from the cup 130 , fluid enters past the radius 154 formed in the outer edge of the cup 130 and past the latching seal 146 to fill the evacuated space between the flat surfaces 145 and 148 of the latching seal assembly flange 138 and the free piston 110 releasing the vacuum and accelerating the free piston 110 down to impact upon the sound transmitting anvil piston 160 sending a sound pulse into chamber 170 , through ports 190 to the bladder 188 and out through the ambient wall of fluid within the bore hole and into the surrounding geological structures. [0068] As the free piston 110 is accelerated when the impulsive sound source 1 fires the face 162 of free piston 110 impacts upon the face 164 of the movable anvil piston 160 and thereby causing the anvil piston 160 to rapidly accelerate downwardly creating the impulse which in turn rapidly expands elastomeric bladder 188 of the sound transmission chamber 170 creating a sound pulse within the well fluid F which propagates through the well casing 202 into the earth strata 204 as a seismic sound pulse within the earth, as shown in FIGS. 11A and 11B . Because the elastomeric bladder 21 of the expansion chamber of Module B, the elastomeric bladder 102 surrounding the free piston chamber of Module E, and the elastomeric bladder 188 of the sound transmission chamber 170 of Module G are all tubular and flexible bladders the pressure of the fluid within these chambers denoted as Ps stands equal to the pressure within the well casing denoted as Pw. [0069] When the impulse type of down-hole sound source 1 of the present invention is suspended by the umbilical cable 2 there is a pressure seal gland 206 which seals the pressure within the well around the umbilical cable 2 within a pressure retaining well cap assembly 208 held in place and sealed at the top of the well casing 202 by bolt circle 210 . The bore hole 212 and well casing 202 may be either a shallow bore such as a few hundred feet or a deep bore such as 10,000 feet and the bore may be fully liquid filled or only partially filled with fluid. The intensity of the impulse the sound source 1 produces when fired is proportional to the static pressure within the bore hole 212 where the sound source 1 is located thus when the sound source 1 is immersed at a shallow depth in the well or bore hole 212 the intensity of the seismic data is lower than when immersed deeply within the bore hole fluid F such as when submerged in water, oil, or in drilling mud. [0070] When the sound source 1 within a bore hole 212 is used for seismic profiling, the sound source 1 may be raised and lowered within the well between shots from the sound source 1 . As the sound source 1 is raised or lowered in the bore hole 212 , the pressure within the well Pw changes depending on the location and depth of the sound source 1 . For acceptable quality in the records of the seismic survey, it is important that the intensity and character of the sound pulse remains constant as the sound source 1 is raised and lowered to a location and fired. Any changes in pressure within the well Pw during the collection of seismic data may affect the intensity and character of the sound pulse, thus the present invention provides for pressure within the well Pw to be adjusted as the impulsive sound source 1 is moved within the well casing 202 or bore hole 212 . [0071] For example, commonly in completing a seismic survey, the sound source 1 is lowered to a lowest point in the bore hole 212 and fired and is then raised to another depth and fired and this is repeated as the sound source 1 is pulled up through the bore hole 212 . One of more pressure sensors 214 on the sound source 1 as well as pressure sensors 216 at the well cap assembly 208 transmit pressure readings to a controller 218 . From these readings the pressure may be manually or automatically increased as the sound source 1 is moved within the bore hole 212 to keep the current pressure the same as the initial pressure readings that were recorded when the survey started at, in this example, the lowest point in the bore hole 212 . A fluid pressure source 220 , the controller 218 , a pressure regulator 222 and using hose or pipe 224 connected through the well cap assembly 208 may supply either high pressure gas, water or other fluid through an input fitting 226 to adjust the pressure within the bore hole 212 . The bore hole 212 may be filled with fluid nearly to the top of the bore hole 212 with a cushion or space of pressurized gas of a short length L such as 10 feet more or less from the pressure retaining well cap assembly 208 to the well fluid level D with the well fluid level D ending above ground level. The impulsive sound source 1 and pressure regulating system 200 may also be used with the fluid F within the bore hole 212 completely filling the bore. The well cap assembly 208 containing the umbilical cable sliding seal 206 and the fluid input fitting 226 and bolt circle 210 is illustrative of where a conventional well head device such as that which is called a lubricator may be used within actual use of the pressure regulating system 200 of the present invention. [0072] The top layer of earth 227 called overburden and the rock formations 204 beneath the overburden 227 are illustrated. A break B in the length of the well casing 202 and bore hole 212 which may be for instance from about one hundred feet to thousands of feet is also shown. The sound source 1 is operational at any depth within the bore hole 212 . However, if a bore hole 212 is too shallow to supply enough hydrostatic pressure for the impulsive sound source 1 to produce an adequate sound pulse, the bore hole 212 may be pressurized to different levels of pressures until a pressure level is reached which provides sound pulses from the sound source 1 with enough intensity and sound characteristics to obtain acceptable high quality seismic records. The pressure regulating system 200 of the present invention may further provide automated adjustments to the pressures to maintain an initial pressure that is recorded at the initial depth of the seismic survey and using a computer processor of the controller adjust pressures to the initial pressure or a desired pressure based on the current pressure readings and/or intensity and characteristics of the seismic data acquired from the impulsive sound source 1 at a location and depth within the bore hole 212 . [0073] The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

A sound source for geophysical studies of the earth for oil, gas and other natural resource exploration and more specifically a streamlined design of a hydraulically controlled impulsive sound source that may be inserted into oil wells and bore holes and a system and method for obtaining high quality seismic records from the impulsive sound source by adjusting and maintaining pressures within the well or bore hole.

FIELD OF THE INVENTION This invention relates to a three-dimensional image display device which creates three-dimensional images directly from the projection data of an X-ray computerized tomography (CT) device. BACKGROUND X-ray CT apparatuses are used to irradiate with X-rays a subject when the periphery of a subject who is lying on the side is irradiated on the table top of a bed. Because the intensity of the X-rays transmitted through the subject is detected with an X-ray detector, projection data can be collected on the horizontal profile of the subject. After the table top of the bed has then been moved, the next projection data can be collected in the same manner for the next horizontal profile (transverse cross-section), so that the projection data can be collected repeatedly by moving the table top until multiple transverse cross-sections of projection data of the subject have been collected by repeating the table top moving and projection data collecting operations. The projection data corresponding to multiple transverse cross-sections of a subject is then processed with a high-speed data processing apparatus and image reconstruction processing is conducted to obtain image data containing multiple transverse cross-sections of a given patient. When X-ray CT apparatuses are used to obtain scanned data, projection data is collected in multiple transverse cross-sections with an X-ray CT device, image data is created for multiple cross-section when image reconstruction processing is applied to the projection data of multiple transverse cross-section with a high-speed data processing device and the image data of these multiple transverse cross-sections is displayed with a display device, so that a laser image or the like can be created of the images of these multiple transverse cross-sections, or burnt on a film which can be observed. An abnormal region of a subject can thus be observed with these operations which are widely used. This made it possible to realize a method wherein image data ranging from several pages to hundreds of pages can be recreated initially with an X-ray CT device. According to recent methods used for scanning of data with and X-ray CT device, projection data of multiple transverse cross-section is collected with an X-ray CT device, image reconstruction processing is applied to the projection data of these multiple transverse cross-sections with a high-speed data processing device, and image data corresponding to multiple transverse cross-section is created, and this image data of multiple transverse cross-sections is stored in electromagnetic disk devices, optomagnetic disk devices, optical disk devices, and other types of magnetic media. The image data of the multiple transverse cross-sections stored in this magnetic media is then read so that the image data can be displayed on a display device and observed. In addition, when the image data of the multiple transverse cross-sections, which has been stored in this magnetic media, is read, image processing can be applied to these images in an image processing device. For example, a three-dimensional construction can be created from this image data with a three-dimensional image display device so that three-dimensional images can then be observed. With the initial X-ray devices, a subject was lying on the side and irradiated with x-rays of a moving table top, enabling reciprocal collection of the projection data of the subject in this manner. However, as the technology used in X-ray CT devices underwent a rapid progress, projection data was collected with the latest X-ray CT devices, so that the subject was lying on the side and X-ray irradiation was performed simultaneously with the movements of the table top. This method for collection of projection data is called helical scanning. Because projection data was collected with the initial X-ray devices when a subject was lying on the side and X-ray irradiation was applied together with the movements of the table top for reciprocal collection of the projection data, the transverse cross-section of the collected projection data was created as a transverse cross-section of image data obtained with reconstructed image data. Specifically, since the transverse cross-section of the image data obtained with the reconstructed image data corresponded to the transverse cross-section of the collected data, the number of the transverse cross-sections of the collected image data was identical to the number of the pages of the image data obtained when image reconstruction operations were performed. In addition, the positions of the transverse cross-sections containing collected projection data were distributed in a dispersed fashion in the body axial direction of the patient. Incidentally, when projection data is collected while simultaneous X-ray irradiation operations are conducted with the helical scanning method, transverse cross-sections of dispersed collected projection data are not present. Because of that, virtual transverse cross-sections are set so that interpolation processing is applied to the projection data to determine projection data corresponding to the virtual transverse cross-sections, and the projection data of these virtual transverse-cross-sections is used when image reconstruction operations are performed. Because virtual transverse cross-sections of this projection data can be set with a considerable amount of freedom, this also makes it possible to select, with a considerable amount of freedom, the number of pages of the image data that can be obtained from the image reconstruction processing with a sequential setting of virtual cross-sections of the projection data, and also to select the interval between the transverse cross-sections. In one example of the initial X-ray CT devices, X-ray detectors where used to detect the intensity of X-rays transmitted through the patient in the body axial direction of the patient, and the projection data was collected in one transverse cross-section of the patient. Due to the rapid progress of the technology used in X-ray CT devices, X-ray detectors are arranged in the latest X-ray CT devices in multiple arrays in the body axial direction of the subject and multiple arrays of X-ray detectors are used for simultaneous collection of the projection data in multiple transverse cross-sections of the subject. When these multiple arrays of detectors are used for simultaneous scanning with the helical scanning method, much more projection data can thus be collected than when scanning was conducted with the initial X-ray CT devices. When these multiple detectors are used with the helical scanning method, since transverse cross-sections of the collected projection data will not be present in a dispersed fashion as was the case with the initial X-ray CT devices, virtual transverse cross-section are generally set so that projection data is determined for virtual transverse cross-sections, while interpolation processing is applied to the projection data and image reconstruction operations are conducted by using the projection data of these virtual transverse cross-sections. Because virtual transverse cross-sections of this projection data can be set with a considerable amount of freedom, this makes it possible to select freely the number of pages of the image data obtained with the image reconstruction processing with the consequent setting of virtual transverse cross-sections of projection data, as well as to select the interval between the transverse cross-sections. During scanning using an X-ray CT device, currently, projection data is collected with X-ray CT scanning devices and image reconstruction processing operations are applied to this projection data with high-speed data processing devices. The result of this image reproduction processing is that multiple obtained transverse cross-section of image data are stored on a storage medium and preserved in magnetic disk devices, optomagnetic disk devices, optical disk devices and the like. The methods used with these results of detection of the X-ray CT devices include burning of images created by using the image data of obtained multiple transverse cross-sections as a result of image reconstruction processing, methods used to observe such a film, observation methods which are used when images are displayed in image observation devices using the image data of multiple transverse cross-sections, image processing involving operations such as three-dimensional image processing performed with image processing devices and applied to the image data of multiple transverse cross-sections obtained as a result of image reconstruction processing, methods used to observe these results, etc. Although each of these usage methods requires parameters optimized for image reconstruction processing, currently, the data that is stored for a long period of time is image data available after image reconstruction, and since long-term storage of projection data prior to the image reconstruction has not been performed because a major computer resource is required for image reconstruction of projection data, there has been no other research of reconstruction processing using optimized image reconstruction processing parameters with each of the respective usage methods. In particular, in cases when the structure of three-dimensional processing is created by using the image data of multiple transverse cross-sections, image reconstruction processing parameters suitable for direct observation of transverse cross-section images can be increasingly obtained with results enabling to use image data of multiple transverse cross-sections of reconstructed images with image reconstruction processing parameters that have been optimized for various types of three-dimensional image processing operations. However, because image data is generally preserved for a long period of time only after image reconstruction, and because long-term storage of the projection data has not been provided, it was thus not possible to examine other objectives of image reconstruction processing which are used for each individual operation. Also, even when long-term storage has been provided, for example of the projection data of X-ray CT devices, since continuous scanning operations with the X-ray CT devices are conducted as a routine with a plurality of scans, it is impossible for an external user to perform image reconstruction by using desirable image reconstruction parameters, which an external user will need for this projection data. Therefore, the image reconstruction of the projection data has been conducted with image reconstruction parameters determined in advance with a routine scan. There are also types of device enabling to perform high-speed image processing, such as three-dimensional image processing which can be applied to image data obtained with image reconstruction using the latest X-ray CT devices. However, even in a system which is equipped with this function, since continuous scanning operations are conducted routinely with many scans, it is still in fact impossible for an external user to perform three-dimensional image processing with this function. Because unlike in the initial CT devices, the noise level of the X-ray scanners is decreased while the spatial density of the X-ray scanners is increased in latest multi-array scanners and CT devices which use the helical scan method, and also the pitch density of helical scan is increased, a very precise spatial distribution of the collected projection data is created. Because of that, a very precise image can be obtained with a small increase of the noise level also when the spatial region in which image reconstruction is performed is reduced, while the number of the image elements participating in image reconstruction is preserved. Accordingly, the spatial precision of the images in the region of interest in a given subject can be increased by decreasing the image reconstruction region for the same image projection data. In addition, since a meaningful image can be obtained with only a small increase of the noise level also with a narrow interval between the image reconstruction screens, this also makes it possible to increase the spatial resolution in the body axial direction. Because a precise spatial distribution of projection data collected with the latest multi-array scanners and CT devices using the helical method has been achieved, CT values (i.e., intensities of the centers of voxels) can now be determined in spatial positions with a small interval not only inside the transverse cross-section of a patient, but also in the body axial direction. In three-dimensional image display devices which use CT image data, voxel data is created from the image data of transverse cross-sections obtained during image reconstruction of projection data accumulated in the body axial direction, and a three-dimensional image is displayed by applying three-dimensional image reconstruction operations to this data. When CT image data obtained with the latest design of multi-array detectors and CT devices using the helical scan method is used, this makes it possible to achieve a very high precision of three-dimensional images. To create three-dimensional images from CT image data, image reconstruction of projection data obtained with X-ray CT devices is performed, the image data of the transverse cross-sections is created, and voxel data is created when this image data is stacked up in the body axial direction. The image elements in the transverse cross-section, for example 512×512 pixels when an image measurement methods using 0.5 mm ×0.5 mm are applied to image data in the body axial direction, for example with an interval of 0.5 mm, creating a stack of 512 sheets, will contain a spatial region corresponding to 256×256×256 mm and a stereoscopic voxel image will be created with 512×512×512 individual voxel data elements. Next, when this stereoscopic voxel image is processed with three-dimensional reconstruction processing using surface rendering and volume rendering, a three dimensional image can be created and displayed. Three-dimensional display devices that have been used up until now perform image reconstruction of projection data obtained with X-ray CT devices and create CT image data. The structure of voxel data is created by using this data. When images containing two-dimensional images of CT images are interpreted by a doctor who is a radiology specialist, a series of CT images displaying a transverse cross-section of a patient is arranged in a plane and the doctor is interpreting the image by observing the image and looking for the presence or absence of abnormalities. On the other hand, to interpret a three-dimensional image, the structure of the voxel data is created from this series of CT image data, a degree of opacity is added to the voxel structure based on the voxel physical properties, that is to say based on the CT values of this voxel data, a light source is applied in the direction of the visual line of an observers who is observing this voxel data and when light emitted from this light source passes through an object, and an image is created with integration of the calculations obtained from attenuation and reflection of this data. Accordingly, because the calculation of integration corresponding to the voxel number of the displayed images will thus be required, the higher the voxel number, the longer the calculation time that will be needed for volume rendering. Specifically, because according to the volume rendering method, each CT value is allocated to the opacity corresponding to light permeation characteristics, and control is maintained over all the voxel values by using light attenuation along the direction of the line of sight based on the variable density calculated with the grey-level gradient method and applied in all the volume points, the brightness value is calculated by multiplying the amount of incident light from a light source by the opacity of the voxel structure. A three-dimensional image is then obtained with sequential integration (recasting) of this data in the direction of the line of sight. Because natural and smooth variations can thus be obtained with the volume rendering method even in edges created by rapid fluctuations of the CT value, this makes it possible to improve dramatically the drawing function which is used to draw fine and detailed tissues, such as the peripheral tissues of blood vessels. Although the surface rendering method represented the main trend of methods used for three-dimensional displaying in the past, the volume rendering method has been used increasingly at present. With similar three-dimensional display devices used up until now, projection data was collected when a subject was scanned with an X-ray CT device and multiple sheets of CT image data were used with the reconstructed image data containing this projection data. Although the density resolution was often more important than factors such as spatial resolution when CT images were observed as two-dimensional images, the spatial resolution is in some cases more important than the density resolution when three-dimensional images created from CT image data are observed, and when two dimensional images are created from two-dimensional image data, different parameters are often optimal to create the image data structure, when compared to cases when three-dimensional images are observed. However, the current situation is such that CT image data is used for reconstruction with image reconstruction parameters optimized for observation of two-dimensional images containing projection data with X-ray CT devices, and three-dimensional image reconstruction is performed by using CT image data optimized for two-dimensional image observation with three-dimensional image display devices. This is because a major computer resource is required for reconstruction of images from projection data and also a major storage capacity is needed to store accumulated data, etc. The following points are worth mentioning with respect to X-ray CT devices: 1) X-ray radiation is emitted with the fan shape along the inner plane of a transverse cross-section from a source of X-ray radiation, enabling operations along the outer periphery of the transverse cross-section of a subject, and X-rays transmitted through the subject are measured for example with a detector which measures 500 items. Therefore, for example 500 items can be measured in one position of the radiation source. Projection data is collected when repeated operations are applied to cover 180 degrees of the outer periphery of a transverse cross-section in this manner. For example, since data is collected in more than 180 directions for each repeated operation, projection data corresponding to 500×180=90,000 will be collected. 2) Convolution processing is conducted after preprocessing and the like has been performed to eliminate noise from the projection data. 3) Data collected in a position corresponding to the transverse cross-section of a subject, for example when a flat surface is set for image elements corresponding to 512×512 pixels creating a construction of image elements having a rectangular shape covering 1×1 mm, and reversed projection is created with a fan shape for projection data, after convolution processing has been conducted from the position of the source of X-rays, when projection data is collected for each image element on the flat surface containing the image elements. 4) At this point, because data creating a reversed projection will not necessarily be cut laterally in the center of the picture elements of a flat surface of a picture containing the picture elements, interpolation processing is conducted in the vicinity of the reversed projection data and similar data is allocated to each picture elements. 5) When this reversed projection processing is applied repeatedly to all of the collected projection data, each picture element of a picture element flat surface corresponding to 512 picture elements×512 picture elements is used for reconstruction of image data, having a value which corresponds to the physical properties obtained with X-ray irradiation of a subject. 6) If the position of the transverse cross-section of a subject is moved, for example by 1 mm in the body axial direction, the image data of the transverse cross-section is reconstructed by collecting projection data in the same manner and applying image reconstruction processing operations to this data. 7) When these operations are repeated if the position of the transverse cross-section of a subject has been moved in the body direction, image data of transverse cross-sections of a subject corresponding to 500 sheets can be collected for example at an interval of 1 mm. When sets of this data are used, this makes it possible to create a voxel space corresponding to 512×512×500 voxels, creating for example the construction of stereoscopic image elements (voxels) of 1 mm×1 mm×1 mm. 8) Three-dimensional images can be created and displayed when three-dimensional image processing is applied with volume rendering and the like to this voxel space created in this manner. FIG. 1 is a block diagram showing a simulation of a three-dimensional display device connected to a network with a conventional X-ray CT device. Element 101 is an X-ray CT device, 111 is a scanner part of a CT device, 112 is a data collection part, displayed as a simulation model in the figure. When detection is performed with an X-ray scanning device so that a subject is scanned with a scanner part using X-rays from a source of X-ray radiation, a digitized system of the collected projection data is created in the data collection part. This digitized output data 122 of the X-ray detector is sent to a preprocessing part 113 and operations during which noise is eliminated from the data, correction is applied, etc., are conducted in the part. The projection data 123 preprocessed in this preprocessing part 113 is then sent to an image reconstruction device 114 . Image reconstruction processing is then applied in the image reconstruction device 114 to the projection data 123 once preprocessing operations have been finished. The image data 124 processed with image reconstruction processing is sent to a console part 115 of the X-ray CT device, the data is displayed and at the same time also stored in image data storage device 116 . Reference numeral 221 indicates image data which is transmitted to a external three-dimensional image display device or the like. Reference numeral 201 designates a three-dimensional image display device, 211 is an image data storage device which stores image data transmitted from the X-ray CT device, and 212 is a three-dimensional image processing device. The three-dimensional image processing device is used so that when an operator specifies image data 222 , signal is received from the image data storage device 211 and three-dimensional image reconstruction operations involving volume rendering and the like are applied to this signal, and the created three-dimensional image 223 is displayed on a console 213 . As was shown in this example, with conventional three-dimensional image display devices, image data processing in CT applications starts with acquiring projection data (the “raw” data set) from a CT scanning device, then reconstructing sliced digitized image data (a voxel data set) based on the raw data, and then rendering three-dimensional images on a computer display screen based on the voxel data set. The rendering processing is always based on the voxel data set which is reconstructed once and stored on disk or other storage device. In other words, the rendering processing did not utilize the projection data set, because reconstruction was very time consuming, so it was not practical to use the projection data for rendering. During scanning operations using an X-ray CT device, projection data is collected with an X-ray CT device, image reconstruction processing is applied with a high-speed data processing device to this projection data, and image data comprising multiple transverse cross-sections obtained as a result of this processing is stored in a magnetic disk device, electromagnetic disk device, optical disk device or the like. While suitable parameters exist for image reconstruction processing according to respective methods using results that have been detected with an X-ray CT device, prior to the present invention, since long-term storage is not provided for projection data if image data exists for image data that has been stored after image reconstruction processing operations, image reconstruction processing has not been realized with parameters that have been optimized for image reconstruction processing according to each respective method. In particular, when the construction of three-dimensional data is created by using the image data of multiple transverse cross-sections, the image reconstruction processing parameters that are compatible with direct observation of images of transverse cross-sections are different from image reconstruction processing parameters that are compatible with processing of three-dimensional images in an increasing number of cases, when it would be desirable to used the image data obtained during image reconstruction. However, image reconstruction processing is generally not conducted for this specific purpose because a major storage capacity is needed in order to accumulate projection data. Further, when long-term storage of projection data is not performed, since most of the time is spent on routine processing performed by image reconstruction devices of X-ray CT devices, the development is not open to users outside of the system. Therefore, the image reconstruction devices thus cannot be used even if reconstruction of projection data is desirable for three-dimensional images because a major computer resource is needed for reconstruction of images using projection data. SUMMARY OF THE INVENTION The present invention includes a method which includes accessing projection data collected by a medical imaging system during a scan of a body, and using the projection data directly to render an image of a region of interest of the body. The invention further includes an apparatus to perform such a method. Other aspects of the invention will be apparent from the accompanying figures and from the detailed description which follows. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the present invention are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which: FIG. 1 is a block diagram showing a simulation of a three-dimensional display device connected to a network with a conventional X-ray CT device; FIG. 2 is a block diagram showing a model of a three-dimensional image display device according to an embodiment of the present invention, which is connected through a network to an X-ray CT device; FIG. 3 is a diagram simulating the processing and the flow of data occurring in a three-dimensional device according to an embodiment of the present invention; and FIG. 4 is a diagram explaining in a simulated form the relationships in the spatial regions of the present invention. DETAILED DESCRIPTION A method and apparatus for creating three-dimensional images directly from projection data are described. References in this specification to “an embodiment”, “one embodiment”, or the like, mean that the particular feature, structure or characteristic being described is included in at least one embodiment of the present invention. Occurrences of such phrases in this specification do not necessarily all refer to the same embodiment. In order to solve the problem mentioned above, the present invention includes a three-dimensional image display device which makes it possible to create and display three-dimensional images directly from projection data. In certain embodiments of the invention, the image display device is equipped with a mechanism for accumulation of projection data collected during X-ray scanning, connected to an X-ray CT device, and with a mechanism for displaying of created three-dimensional images using this projection data, without using slice or volume image data obtained during image reconstruction processing with an X-ray CT device. In this three-dimensional image display device is deployed a mechanism setting spatial regions that are of interest for displaying of three-dimensional images, that is to say spatial regions in which three-dimensional images are created with three-dimensional image reconstruction; and a mechanism setting in advance the spatial position and the spatial distribution of a plurality of points used to determine the physical amount, that is to say the CT values, of the characteristics of a subject used for reconstruction of three-dimensional images. Reconstruction processing is then conducted by using the projection data in the spatial positions determined within these specified spatial regions of interest, and the CT values of the subject are obtained. Reconstruction processing operations of three-dimensional images are applied to a data set containing the CT values obtained in this manner and the obtained results are displayed as three-dimensional images. When three-dimensional images were created and displayed according to the prior art, images were reconstructed with slice data in different cross-sectional positions from the projection data of an X-ray CT device, and three-dimensional voxel data was created by stacking up slice data in these different cross-sectional positions. Volume rendering processing operations and similar processing operations were then applied to this three-dimensional voxel data to create and display three-dimensional images. In contrast to that, the three-dimensional image display device of the present invention is equipped with a mechanism to set spatial regions of interest in which reconstruction of three-dimensional images is conducted, that is to say spatial regions of interest for displaying of three-dimensional images, and with a mechanism setting in advance the spatial position and the spatial distribution of points determining the physical properties, that is to say the CT values, of a subject used for reconstruction of three-dimensional images. Reconstruction processing is then conducted by using the projection data in the spatial positions specified within these specified spatial regions of interest, displaying the physical amounts, i.e., the CT values, of the characteristics of the subject. Because of that, reconstruction processing of three-dimensional images is applied to data sets with CT values inside these regions of spatial interest obtained in this manner and the obtained results are displayed as three-dimensional images. In addition, taking into account regions of spatial interest determining the data sets with physical amounts displaying the characteristics of a subjects, e.g., the CT values, and the spatial positions and the spatial distribution of a plurality of points determining the CT values, as well as the influence exerted by this on the image quality of three-dimensional images obtained by reconstructing three-dimensional images using the data sets containing these CT values; the device is equipped with a mechanism to enable the determination of spatial regions of interest determining a data set of CT values by performing image reconstruction of projection data, as well as to determine the spatial position and the spatial distribution of a plurality of points determining the CT values when image reconstruction operations are conducted with projection data. Whereas according to prior art projection data was applied to the entire region in which projection data was present and this projection data was then used when image reconstruction processing operations were conducted with X-ray CT devices, with the three-dimensional display device of this invention, a spatial region of interest in which three-dimensional images are to be created is set in advance, and image reconstruction operations are applied only inside this region of spatial interest. In addition, while the dimensions and the number of the image elements in image planes used for image reconstruction were determined in advance with X-ray CT devices according to prior art, and image reconstruction operations were applied to the central point of these image elements, with the three-dimensional display device according to this invention, the spatial position and the spatial distribution of multiple points determining the CT values from the viewpoint of the image quality of three-dimensional images to be created are determined in advance and image reconstruction operations are conducted by using projection data in these points. Moreover, because a fine point distribution is created in regions exerting a major influence on the image quality of three-dimensional images, this makes it possible to greatly reduce the amount of calculations required for image reconstruction, so that the point distribution will be sparse or there will be no distribution in spatial areas which will have only a small influence on the image quality of three-dimensional images. Since this makes possible to greatly reduce the amount of calculations that are required for processing of three-dimensional images, image reconstruction processing can be performed from projection data every time when a three-dimensional image is created, and the result can be used to created three-dimensional images. Because during ray tracing operations using volume rendering, ray-tracing operations are conducted within a range having a conical shape inside a spatial regions occupied by a subject from the viewpoint of the region of interest which is irradiated with the rays, volume rendering can be conducted by applying the CT values to the rays used during the processing of the ray tracing operations. Accordingly, when the rays to be used for ray tracing operations of volume rendering are determined in advance, this makes it possible to use only points on the rays which are used for ray tracing for the reconstruction of images from the projection data. Also, because attenuation of light is performed according to the opacity of the subject during the ray tracing operations, the spatial region contributing to ray tracing operations is limited to the depth direction of the rays. Moreover, lateral opacity can be set to 0 and ignored also from the viewpoint of the region of interest for the rays. Accordingly, reconstruction of images from the projection data can be performed only in the spatial regions which contribute to ray tracing operations. In other words, because according to this invention, certain points are set for rays, wherein the rays are crossing the regions of spatial interest, image reconstruction operations are processed by using set of projection data in the vicinity of these points, and the results of these image reconstruction operations are used for volume rendering with the CTV values of the rays obtained in this manner. Because the region of interest in a three-dimensional display is normally quite small when compared to spatial regions obtained with X-ray CT projection data, the amount of calculations can be greatly reduced when this invention is used. This makes it possible to perform processing of image reconstruction operations with optimized data, which is determined for each instance when processing of three-dimensional images is conducted. During image reconstruction operations performed with an X-ray CT device, image reconstruction regions are set which are smaller than the regions obtained with projection data, and the processing operations are performed so that the image data is obtained with smaller dimensions of image elements used for image reconstruction processing in the reconstructed regions. According to the characteristics of this invention, the density of points creating the CT values of rays, and the density in the direction of the rays and of the regions in which ray tracing is applied with volume tracing, is determined in advance from the viewpoint of volume rendering. Image reconstruction processing from projection data is performed based on the spatial position and spatial distribution of multiple points which are determined by the number of rays cast and the number of sample points along each ray taking into account volume rendering processing at later stage. The image reconstruction operations are thus characterized by the fact that projection data which passes through these points and through the vicinity of this data are reconstructed. According to conventional methods, interpolation processing operations were conducted several times during the processing of three-dimensional reconstructed images and during image reconstruction processing of projection data: (1) When image reconstruction processing was conducted based on the projection data of a helical scanner, interpolation processing was applied to the projection data of a helical scanner to determine the projection data passing through a transverse cross-section of a reconstructed image; (2) During the processing of image reconstruction operations, interpolation processing was applied to the projection data established in (1) in order to determine the projection data passing through image elements of an image plane; and (3) As the image data of reconstructed cross-sections was stacked up in the direction of the bodily axis to create the structure of voxel data used during the three-dimensional processing, interpolation processing was conducted before and after the profile image data is used to obtain the desired interval in the axial direction; and (4) Interpolation processing was applied to voxel data to determine the CT values of rays with ray casting during volume rendering. According to embodiments of this invention, the points corresponding to the CT value are determined in advance as an important value for ray casting of volume rendering operations, and image reconstruction is conducted so that interpolation processing is applied to the projection data passing through the vicinity of these points. Ray casting processing is therefore applied to volume processing by using this determined CT value. Accordingly, since interpolation processing can be performed so that data interpolation processing is conducted only once for projection data passing through this vicinity, this makes possible to greatly reduce the number of times when interpolation processing is required, while the image quality can be also greatly improved when compared to methods which are used currently to create three-dimensional images. The method of this invention enables to significant reduction in the amount of calculations used for data processing. In particular: (1) Because the points of spatial regions in which image reconstruction is to be conducted can be determined in advance, this made it possible to greatly reduce the amount of calculations which are used for data processing. (2) Since the number of times when interpolation of data is conducted can be reduced, this made it possible to greatly reduce the amount of calculations which are used for image reconstruction processing and for image reconstruction operations during processing of three-dimensional images. Also, when the number of incidences of data interpolation processing is reduced, the quality of the image is also greatly improved. (3) Because conditions for image reconstruction processing are created so that data is created in advance for points which are important for ray casting processing of volume rendering operations, the amount of calculations which are used for processing with reconstruction of three-dimensional images is greatly reduced. Because of that: (1) Since the amount of calculations which are used for data processing has been greatly reduced, this enabled direct creation of three-dimensional images for projection data, which is something that was not possible according to routines available up until now. (2) Based on the premise that three-dimensional images can be created, an optimized pattern can be created for reconstruction of three-dimensional images with the image reconstruction parameters of projection data. (3) Since the amount of calculations used for data processing has been reduced, reconstruction of images can be performed with a narrower interval when compared to prior art, which makes it possible to further improve the image quality of three-dimensional images. According to embodiments of this invention, spatial coordinates are determined in advance for points within a spatial region which is used for calculation of volume rendering and in spatial regions of the volume data used with volume rendering, and CT values are determined with image reconstruction processing which is applied in the position of spatial coordinates of each point present during image reconstruction processing which uses projection data. Next, during processing of volume rendering when a three-dimensional image is created, volume rendering is conducted by using the CT values determined during image reconstruction processing applied to the spatial coordinate positions of each of these points. From the viewpoint of the situation existing when a three-dimensional image is created, because the spatial region of the volume data which is used during volume rendering is only one part of the total volume data, the spatial regions in which reconstruction of the projection data is conducted can thus be greatly reduced, and this in turn makes it possible to cut down considerably on the amount of computer resources which are required for reconstruction of images. At the same time, also the time required for calculations which are need for reconstruction of images can be reduced in this manner by a great margin. In addition, because CT values are determined in advance with image reconstruction processing for the points that are required for volume rendering, interpolation processing of voxel values that were needed with conventional volume rendering operations is no longer required. The time required for calculations during three-dimensional image reconstruction is therefore reduced and deterioration of the precision accompanying interpolation is prevented, which makes it possible to improve the image quality. The following is an explanation of a system of a three-dimensional display device creating three-dimensional images directly from the projection data of an X-ray CT device according to an embodiment of this invention. FIG. 2 is a block diagram showing a model of a three-dimensional image display device according to an embodiment of this invention, which is connected through a network to an X-ray CT device. Element 101 designates an X-ray CT device, 111 is a scanner part of the X-ray CT device, and 112 designates a data collecting part. Projection data acquired when X-ray scanning of a subject is performed with the scanner part of an X-ray scanner is detected and digitized in a data acquisition part. The digitized output data 122 of the X-ray detector is sent to a preprocessing part 113 and preprocessing, such as noise elimination and standardization, is conducted in this part. Projection data 123 , which has been preprocessed in the preprocessing part 113 , is sent to an image reconstruction device 114 and at the same time, it is also sent to a projection data storage device 117 where it is stored. Image reconstruction processing operations are then applied by the image reconstruction device 114 to the projection data 123 when preprocessing is finished. Reconstructed image data 124 is sent to a console 115 and displayed, and at the same time also stored in an image data storage device 116 . Number 321 indicates projection data which is transmitted from the data storage device 117 to a three-dimensional display device. Because the X-ray CT device in some cases will not have this projection data storage unit 117 , the data 123 will be in such a case preprocessed with the preprocessing part 113 and sent directly to a three-dimensional image display device and stored. Element 301 designates a three-dimensional display device, and 311 is a data storage device which stores projection data 321 which has been sent from an X-ray CT device. Number 312 indicates the setting of a spatial region for image reconstruction based on a spatial region of interest for creation of three-dimensional images, having a function which sets image reconstruction regions. This functionality can be physically implemented in the image reconstruction processing device 313 . The image reconstruction processing device 313 requests image reconstruction processing of CT values in points specified within a specified region for image reconstruction. Reference numeral 324 represents a data set of CT values used for image reconstruction, which is sent to the three-dimensional image processing device 314 . A three-dimensional image processing device 314 receives the signal containing the data set 324 with the CT values used for image reconstructions from the three-dimensional image processing device 313 , three-dimensional image reconstruction processing is applied to this data with volume rendering and the like, and the created three-dimensional image data 315 is displayed on a console 315 . FIG. 3 is a diagram simulating the processing and the flow of data occurring in a three-dimensional device. When X-rays 121 are transmitted through a subject with X-ray scanning by a scanner part 111 of an X-ray CT device, these X-rays 121 are detected with an X-ray detector and digitized data is created in a data acquisition part 112 . This digitized projection data 122 is sent to the preprocessing part 113 and processing such as noise elimination or correction and the like is applied to this data in this part. The projection data 123 , which has been preprocessed in the preprocessing part 113 , is sent to the image reconstruction part 114 , and at the same time, it is also sent to the image data storage device 117 where it is stored. When preprocessing is finished, image reconstruction processing operations are applied with the image reconstruction device 114 to the image projection data 123 . The reconstruction image data 124 is sent to and displayed on the console 115 of the X-ray CT device, and at the same time also stored in an image data storage device 116 . Number 321 indicates projection data which is sent from the data storage device 117 to a three-dimensional display device. A projection data storage device 331 of the three-dimensional display device stores projection data 321 , which has been transmitted from the X-ray CT device, and scan projection data 322 , specified by an operator, is sent to a reconstruction region setting part 312 of an image reconstruction processing device. Based on the position of the points in the spatial regions in which image reconstruction is performed, requested from spatial regions for creation of three-dimensional images by the reconstruction region setting part 312 , image reconstruction parameters are set and the required projection data 323 is prepared. During image reconstruction processing 313 , image reconstruction processing is determined with the CT values of points specified within a specified image reconstruction spatial region. Three dimensional image processing 314 is applied to a data set 324 containing the CT values for image reconstruction. Three-dimensional image processing 314 is used to perform reconstruction of three-dimensional images, including volume rendering and the like, and the created three-dimensional images 325 are displayed by a console 315 . When an operator selects scanning of three-dimensional images to be created, instruction 326 is transmitted which specifies the required projection data for the projection data storage device from the console. Based on this instruction, scan projection data 322 , specified by an operator, is sent by the projection data storage device to the reconstruction region setting part 312 of the image reconstruction processing device. When an operator determines a spatial region of interest for a three-dimensional image to be created by using the projection data, the spatial distribution and the spatial position of points determining the CT values are set, and instruction 327 is sent from a console to the reconstruction region setting part. Based on this instruction, the reconstruction region setting part 312 sets the image reconstruction parameters and prepares the required projection data 323 . During image reconstruction processing 313 , the CT values of points that have been specified within an image reconstruction region are determined with image reconstruction processing. Three-dimensional image processing 314 is then performed by using data set 324 with the CT values determined during the image reconstruction. Three-dimensional processing 314 is then performed to achieve three-dimensional image reconstruction with operations such as volume rendering and the like, which are applied to the data which has these CT values, and the created three-dimensional image 325 is displayed on the console 315 . When an operator observes a three-dimensional image, the parameters or the regions in which three-dimensional images are to be created can be modified as required by the operator when an instruction 327 is sent from the console. Using updated parameters for image reconstruction, reconstruction operations are performed for reconstruction of images and for reconstruction of three-dimensional images. Because according to this invention, the time required for reconstruction of images has been greatly reduced, the processing of this series of scans can be conducted in an interactive manner. FIG. 4 is a diagram explaining in a simulated form the relationships in the spatial regions of this invention. Reference numerals 511 , 512 , 513 indicate respective planes of the spatial regions in which projection data of a subject is collected, namely plane X-Y, plane X-Z, and plane Y-Z. Reference numerals 514 , 515 , 516 indicate respective planes of the regions of interest for formation of a three-dimensional images, namely plane X-Y, plane X-Z, and plane Y-Z. Reference numerals 521 , 522 , 523 indicate the planes of the position of the viewpoint in which a three-dimensional image is created, namely plane X-Y, plane X-Z, and plane Y-Z. Reference numerals 531 , 532 , 533 indicate the planes of the spatial regions of the rays used during ray tracing processing when a three-dimensional image is created, namely plan X-Y, plane X-Z and plane Y-Z. The projection data of spatial regions indicated by 511 , 512 , 513 is collected with scans of the X-ray CT device. This projection data is transferred according to this invention to a three-dimensional image display device. An operator determines the spatial regions for creation of three-dimensional images, that is to say spatial regions of interest 514 , 515 , 516 . After that, the viewpoint positions 521 , 522 , 523 are set. Numbers 531 , 532 , 533 indicate plane X-Y, plane X-Z and plane Y-Z, which have a conical shape and which include the line of sight when a region of interest is seen from said viewpoint. The rays used during the ray tracing operations create three-dimensional images including the inner part of these spatial regions. Taking into account the image quality of the three-dimensional images, when the ray density is set with a radial shape which is extending from said viewpoint inside this conical region, the position of the point determining the CT value is set on the line of each of these rays. In other words, the position of the point determining the CT value is set on the line of the rays which are used for ray tracing operations. The positions of the points determining the CT values are thus indicated with the reconstruction region setting part. The image reconstruction device uses projection data passing through the points determining the CT values and through the vicinity of these points according to this indication and the CT values of the indicated points determining the CT values are determined. The three-dimensional image processing device performs three-dimensional processing by using the data set containing the CT values of the determined points with the indicated CT values. Interpolation processing is therefore not necessary because the CT values of the points on the line of the rays are determined by using ray tracing operations for processing of three-dimensional images. While in the example explained above, projection data was transferred through a network from an X-ray CT device to a three-dimensional display device, embodiments of the invention may include transfer of projection data from an X-ray CT device to a three-dimensional image device off line, through a storage medium, in the same manner. Although in the apparatus explained up until now, an X-ray CT device was separate from the three-dimensional display device, in certain embodiments of the invention the function of three-dimensional image display device is included in an X-ray CT device. While it was explained up until now that the perspective projection method was used for processing of volume rendering operations, in certain embodiments of the invention the parallel processing method or another method can be also included in the same manner in the processing of volume rendering operations. Although the three-dimensional processing explained up until now related to volume rendering processing, this invention can be also used with MIP, ray sum processing and other types of processing used for three dimensional processing operations. It is further also possible to use displaying of two-dimensional cross-sections, displaying of two-dimensional images of curved cross-sections and other types of processing of two-dimensional images. Although an X-ray CT device was used as an example in the described provided up until now, this invention also includes cases when line data such as data obtained from an ultrasonic device is stored, when data is generated by so called MR equipment or when data is generated by so called nuclear medicine apparatuses using SPECT or the like without the projection data of an X-ray CT device, as well as systems in which image reconstruction is conducted with optimal new parameters applied as required. With conventional devices for displaying and creating three-dimensional images, profile data was created when image reconstruction was applied to projection data with X-ray CT devices. Next, three-dimensional voxel data was created by stacking up slice data in different positions of the cross-sections. Three-dimensional image reconstruction processing was then applied with volume rendering and similar operations to this three-dimensional voxel data and three-dimensional images were created and displayed. In contrast to that, the three-dimensional display device of this invention is provided with a mechanism to set regions of spatial interest, i.e., regions of spatial interest in which three-dimensional image reconstruction operations are conducted to display a three-dimensional image; and with a mechanism setting in advance the spatial position and the spatial distribution of points determining the physical amounts, i.e., the CT values, indicating the characteristics of a subject used for reconstruction of three-dimensional images. Reconstruction processing is conducted by using projection data in the spatial positions which have been specified within the regions of spatial interest determining the physical amounts, i.e., the CT values, indicating the characteristics of the subject. Therefore, the results obtained with reconstruction processing of three-dimensional images applied to the data cats with the obtained CT values are displayed as three-dimensional images. Also, because the data sets containing the physical amounts, i.e., the CT values indicating the characteristics of a subject, are spatially distributed in the present spatial regions with the points in which CT values are present, taking into account the influence exerted in the image quality of the three-dimensional images obtained with the reconstruction processing operations for three-dimensional reconstruction using these data sets, the invention is provided with a mechanism which makes it possible to determine regions of spatial interest determining CT values with reconstruction of images using projection data, as well as the spatial position and the spatial distribution of multiple points determining the CT values within a regions of interest. According to conventional X-ray CT devices, image reconstruction operations were conducted by using the projection data in all the regions in which projection data was present. According to the three-dimensional device of this invention, regions in which three-dimensional images are to be created are set in advance and image reconstruction operations are conducted only in these regions. In addition, although with X-ray CT devices according to prior art, the dimensions and the number of image elements used for image reconstruction were determined in advance and image reconstruction operations were applied to the central point of these image elements, according to the three-dimensional display device of this invention, the positions and the distribution of points having the CT value are planned in advance from the viewpoint of the image quality of the three-dimensional image to be created, and image reconstruction processing is conducted by using projection data so that it is applied in these points. Because of that, image reconstruction processing operations have thus become unnecessary in parts containing regions that have no relationship to creation of three-dimensional images. Moreover, because the points in parts which exert a major influence on the image quality of three-dimensional images are distributed with precision also in the spatial regions in which three-dimensional images are created, while in parts which exert small influence on the image quality of three-dimensional images, the points are distributed sparsely or there is no distribution of such points, this made it possible to greatly reduce the amount of calculations required for image reconstruction. Because the amount of calculations involved in image reconstruction has thus been greatly reduced, every time a three-dimensional image is created, image reconstruction operations can be conducted from projection data, and three-dimensional images can be created from the results of these operations. Because during ray tracing processing using volume rendering, ray tracing is conducted in a range which has a conical shape, in which radiation is applied to regions of interest of a subject from the viewpoint of a spatial region which is occupied by a subject, volume rendering can be conducted when CT values have been applied to these rays using processing of these ray tracing operations. Accordingly, because the rays to be used for ray tracing with volume rendering are determined, the processing can be conducted only in the points of these rays by using ray tracing when image reconstruction is conducted from this projection data. Further, because the light is attenuated by the degree of opacity of the object during ray tracing processing, the spatial regions contributing to ray tracing are limited only to the direction of the depth of the rays. Further, lateral opacity, namely on the side of the regions of interest for the rays, can be set to zero and ignored. Accordingly, image reconstruction operations from the projection data can thus be conducted only in spatial regions which contribute to ray tracing processing. In other words, image reconstruction processing operations are conducted by using sets of projections data passing through the vicinity of these points in points set on rays intersecting other rays in the regions of interest of a subject, and the CT value of rays obtained as a result of this processing of image reconstruction are used to perform volume rendering. Because the regions of interest in a three-dimensional image display are normally smaller when compared to regions of interest obtained with the acquisition of X-ray CT projection data, the method of this invention makes it possible to realize image reconstruction operations which use projection data each time for processing and displaying of three-dimensional images. Also, when image reconstruction is conducted with an X-ray device, regions that are smaller than regions in which projection data is acquired are set, and image processing operations are applied to these regions. According to this invention, the density in the direction of the rays and the regions in which ray tracing processing is performed for volume rendering are set in advance, the density contributing to the CT values on the rays is determined from the viewpoint of the contribution to the volume rendering, and the positions of the points in which CT values are determined and the spatial regions in which image operations are conducted are determined, so that image reconstruction processing operations are conducted by using projection data passing through the vicinity of these points. According to the characteristics of a second embodiment of this invention, regions in which ray tracing processing of volume rendering is conducted and the density in the direction of the rays are determined in advance, the density contributing to CT values of the rays is determined from the viewpoint of the contribution to volume rendering, the spatial regions in which image reconstruction operations are conducted are determined by this, the participating voxel values are determined, and image reconstruction operations are conducted by using the projection data passing through the vicinity of this voxel data. According to the method of this invention, the points in which CT values are required for ray casting processing applied to volume rendering are determined in advance, image reconstruction operations are performed with interpolation processing applied to projection data passing through the vicinity of these points and the CT values are determined. The data sets containing the CT values obtained in this manner are used to perform ray tracing processing of volume rendering. Therefore, because data interpolation processing can thus be conducted only once, this makes it possible to greatly reduce the number of times when interpolation processing is conducted, which is also accompanied by a greatly improved image quality. The method of this invention made it possible to greatly reduce the amount of calculations which are required for processing of data. (1) Because the points and the spatial regions in which image reconstruction operations are performed are determined ahead of time, this made it possible to greatly reduce the amount of calculations which are required for processing of image reconstruction operations. (2) Because the number of times when data interpolation processing can be conducted has been greatly reduced, the amount of calculations required for processing of image reconstruction operations and for processing of reconstruction of three-dimensional images has been greatly reduced. This also made it possible to improve the image quality because the number of times when data interpolation processing is conducted has been reduced. (3) Since the data of CT values is determined in advance for positions important for processing of ray tracing operations with volume rendering and made available for processing of image reconstruction operations, this made it possible to greatly reduce the amount of calculations which are required for processing during reconstruction of three-dimensional images. Therefore, since the amount of calculations required for data processing has been reduced as described in (1) above, this made it possible to create three-dimensional images directly from projection data, which has not been possible with routines that are currently used. Since creation of three-dimensional images is based on the premise described in (2) above, this made it possible to use parameters that are optimized for three-dimensional images with image reconstruction parameters of projection data. And since the amount of calculations has been reduced as described in (3) above, image reconstruction operations can thus be performed with a narrower interval than according to prior art, which in turn made it possible to improve the image quality of three-dimensional images. According to this invention, the spatial coordinates of points in spatial regions used for calculation of volume rendering and spatial regions of data used during volume rendering are determined in advance, and CT values of points used for image reconstruction operations are determined and applied to positions of spatial coordinates in respective points for image reconstruction processing using projection data. Next, during processing of volume rendering to create three-dimensional images, volume rendering is conducted by using CT value determined during image reconstruction processing applied to respective points in the positions of the spatial coordinates. Because the spatial region containing data used with volume rendering is one part of the spatial region representing all of the projection data, this makes it possible to greatly reduce the spatial regions in which reconstruction processing is conducted with projection data, which in turn makes it possible to greatly reduce in this manner the amount of calculations which are required for image reconstruction. At the same time, the calculation time required for image reconstruction processing is also greatly reduced. In addition, because CT values of points required for calculation of volume rendering are determined in advance with image reconstruction processing operations, interpolation processing between the voxel units, which was required with volume rendering according to prior art, is no longer necessary, enabling to decrease the calculation time, as well as to prevent deterioration of the precisions which accompanies interpolation, and making it possible to greatly improve the image quality. Thus, a method and apparatus for creating three-dimensional images directly from projection data have been described. Software to implement the technique introduced here may be stored on a machine-readable medium. A “machine-accessible medium”, as the term is used herein, includes any mechanism that provides (i.e., stores and/or transmits) information in a form accessible by a machine (e.g., a computer, network device, personal digital assistant (PDA), manufacturing tool, any device with a set of one or more processors, etc.). For example, a machine-accessible medium includes recordable/non-recordable media (e.g., read-only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; etc.), etc. “Logic”, as is used herein, may include, for example, software, hardware and/or combinations of hardware and software. Although the present invention has been described with reference to specific exemplary embodiments, it will be recognized that the invention is not limited to the embodiments described, but can be practiced with modification and alteration within the spirit and scope of the appended claims. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than a restrictive sense.

An imaging device accesses projection data collected by a medical imaging system during a scan of a body. The imaging device uses the projection data directly to render an image of a region of interest of the body.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a Continuation-In-Part of PCT Application No. PCT/US2007/025749, filed Dec. 17, 2007, incorporated herein by reference in its entirety, which claims priority from U.S. Provisional Application 60/875,272, filed Dec. 15, 2006, incorporated herein by reference in its entirety. This application claims priority from U.S. Provisional Application 61/182,597, filed May 29, 2009, incorporated herein by reference in its entirety. SEQUENCE LISTING The instant application contains a Sequence Listing which has been submitted via EFS-Web and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Nov. 5, 2009, is named 04643401.txt, and is 3,683 bytes in size. BACKGROUND Technological advances allow the manipulation of extremely small units of matter, even individual atoms, opening up the possibility of macrofabrication technologies. Such technologies could be used to design nano and micro-scale machines, or to accurately control individual elements in larger materials or machines. Practical realization of these technologies is blocked by the inability to adapt experimental and small scale techniques to the larger scales required of industrial production. Conventional materials production is a linear process. Doubling the amount of material created requires twice the production time. Linear scaling of production is a critical problem if the goal is to create useful, i.e. macroscopic, quantities of microscopic building blocks with sophisticated internal structures. Exponential growth is the most elegant and effective solution to the problem, as demonstrated by biological systems, in which a single cell generates offspring which themselves can build more copies. A single cell containing the necessary information can also divide and develop into a living organism, demonstrating that large, complex systems can be built and operated from self-reproducing units. While nature teems with organisms that readily reproduce, no one has yet succeeded in making an artificial material that can repeatedly copy itself. Making a material which self-replicates presents not only a significant scientific challenge but also the potential for applications which bridge the microscopic and macroscopic worlds. Self-replication leads to exponential growth providing a practical means to scale up production of components for nanomachines and larger scale more functionally complex assemblies. Demonstrating self-replication and developing the science behind it therefore represents an important step for nanotechnology and for enabling the practical development of the technology. SUMMARY OF THE INVENTION The invention encompasses, inter alia, an artificial composition capable of replication, methods of constructing and replicating such compositions, methods of creating novel materials by use of such methods and compositions, and the novel materials so made. In one embodiment, the invention is a replicable artificial composition, comprising: (a) at least two particles, P 1 and P 2 , bound together, (b) a surface-exposed first and second chemical moieties A 1 and A 2 , which are able specifically and reversibly interact with chemical moieties B 1 and B 2 ; wherein one of said A 1 -B 1 and A 2 -B 2 interactions can be modified to make the A1-B1 interaction irreversible under conditions in which the A 2 -B 2 interaction is reversible. Suitable particles may be any macromolecule. In some embodiments, the particles are colloidal particles, which may be composed of a polymer, a metal, a glass, a ceramic, a crystal, for example. Particles may be uniform in some embodiments. In other embodiments, the particles are nonuniform at their surface (patchy). Patchy particles allow, in some embodiments, directionality in the relationship with other particles. Interactions between the particles are governed, at least in part, by chemical moieties that are present on the surface of the particles. Such chemical moieties may be inherently part of the particle, or added as a coating. In exemplary embodiments, such chemical moieties comprise DNA or other nucleic acid. In exemplary embodiments, suitable DNA sequences comprise a sequence selected from the group consisting of: CCATGCGCATGG (SEQ ID NO: 1); AGCATGCATGCT (SEQ ID NO: 2); AGCTGTCAAGGA (SEQ ID NO: 3); GCCTCTGAGAGA (SEQ ID NO: 4); and the complement of any one such sequences. In some embodiments, the DNA sequences are palindromic. Interactions between particles can also be moderated by other factors. For example, the surface of the particle may also contain, or be modified to contained, additional molecules that minimize the effect of van der Waals forces between particles. Polymers such as polyethylene block copolymers are useful in this regard. Particle interactions can be modified by additional chemical and physical forces, including pH, ionic strength, charge, temperature, concentration, magnetic fields, electrical fields, gravitational fields, photons and waves, and gradients of temperature, charge, magnetic field, concentration etc. Temperature is especially useful in this regard. Interactions may be formed and reversed under different conditions. Interactions can be made irreversible by, for example, making reversibility dependant on a condition that is not provided. Reversible interactions between moieties can also be made irreversible by the formation of chemical bonds between such moieties, especially covalent chemical bonds. Exemplary chemical bonds includes disulfide bonds, amine, amide and ester bonds, etc. In one embodiment, the interaction between complementary strands of DNA is made irreversible by the addition of an intercalating agent, such as psoralen, and the addition of energetic particles that cause said complementary strands of DNA to cross link, and thereby create a covalent bond between strands. The type of artificial compositions suitable for replication are not limited in terms of the number of particles, the shape or size of the particles, or the spatial relationship between the particles. Thus, an artificial composition suitable for replication may be linear, planar, or three dimensional. Another aspect of the invention includes methods of making an artificial composition capable of replication, which is used as a seed for the replicative copying. Such artificial compositions may be made with the assistance of optical tweezers, holographic optical traps, magnetic fields, electrical fields, gravitational fields and the like. In one embodiment, the seed comprises at least at least two particles, P 1 and P 2 , bound together, which possess surface-exposed first and second chemical moiety, A 1 , A 2 , wherein A 1 and A 2 may be the same or different, and are suitable for directing interactions with particles that are not part of the seed. Holographic optical traps are particularly useful for directing the spatial relationship between particles in one, two and three dimensions. Another aspect of the invention is a method of copying such an artificial composition by a replicative process. A method of making a copy of an artificial composition, comprising constructing a seed particle comprising at least two particles, P 1 and P 2 , bound together with a surface-exposed first and second chemical moiety, A 1 , A 2 , wherein A 1 and A 2 may be the same or different. The seed particle is exposed to (a) at least one third particle P 3 comprising at least a third surface-exposed chemical moiety B, wherein A 1 B specifically and reversibly interact, and at least a fourth surface-exposed chemical moiety C, wherein C specifically and reversibly interacts with a fourth chemical moiety D, wherein C and D are the same or different, and to (b) at least one fourth P 4 particle comprising the surface-exposed chemical moiety D, and a surface-exposed chemical moiety F, wherein F specifically and reversibly interacts with A 2 . The seed of P 1 and P 2 and the particles P 3 and P 4 are mixed under a first condition favorable for specific and reversible A 1 -B, A 2 -F, and C-D interactions. Next, a second condition is applied that causes the C-D interactions to become irreversible under at least a third condition, wherein said third condition reverses A 1 -B and A 2 -F interactions. When such third condition is provided, the A 1 -B and A 2 -F interactions are reversed, but the C-D interactions are not. The result is that the particles P 3 and P 4 are associated such their relationship replicates that between P 1 and P 2 , thereby copying the seed. This method can be repeated, producing more copies of the seed. Preferably, the daughter of each replicative event (e.g. P 3 -P 4 ) is suitable for use as a seed for further replication, thereby achieving exponential growth of the replicable composition. The above method can be practiced with any of the particles, chemical moieties, DNA sequences etc. as are defined elsewhere herein. In another aspect, the invention comprises materials made by the above methods. Because the invention provides means for generating multiple copies of particles in a particular arrangement, the invention is useful for creating designed components for nano- and micro-scaled machines, and materials with novel properties. For example, the presence of certain elements (such as particles susceptible to variation in charge, energy state etc) can be controlled. Accordingly, the present invention provided methods for making materials such as photonic crystals, silicon wafers, and the like. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 demonstrates how exemplary DNA sequences can be used to control particle interactions. DNA sequences interact with complementary sequences, permitting specific and reversible interactions. Certain interactions can be made irreversible. For example, when the compound psoralen is added to DNA, and then exposed to UV light, the psoralen cross-links between thymidine in complementary A-T pairs, thereby chemically binding the complementary strands. Sequences lacking A-T pairs are not cross linked. Therefore, sequence selection can be used to control whether a given interaction is reversible or not. DNA linkers disclosed as SEQ ID NOS 6, 1, 1, 1 & 1, respectively, in order of appearance. FIG. 2 illustrates complementary pairs of DNA sequences used in subsequent figures (SEQ ID NOS 1, 1, 2, 7 & 4, respectively, in order of appearance). FIG. 3 illustrates colloidal beads, each of which contains different collections of complementary DNA strands and therefore direct the interaction between different beads. FIG. 4 summarizes the kinds of reversible and permanent links that can be made between the four differently functionalized colloidal particles A, A′, B, and B′. FIG. 5 illustrates the use of optical tweezers to construct, from two different colloidal beads, a specific arrangement of beads. FIG. 6 shows the basic replication scheme. FIG. 6A shows a schematic diagram of a linear seed comprising two types of particles, A and B, which are first arranged and then permanently bound through the use of psoralen and UV light. FIG. 6B shows complementary particles specifically binding to particles in the seed, using the presence of complementary DNA species. FIG. 6C shows a completed complementary daughter strand. After treatment with psoralen and UV, the daughter strand becomes cross-linked. There is no crosslinking, however, between the DNA strands that direct the association between the seed and daughter strands, because the DNA species lack AT pairs. The result ( FIG. 6D ) is that when the temperature is raised, the seed-daughter interaction is reversed, but not the interaction between the particles within a seed, or within the daughter. The result is that the daughter strand has copied the seed. FIG. 7 illustrates how palindromic DNA ends can self-anneal, rather than annealing with a palindrome on another particle. One solution is to provide a “protection strand” that prevents self-annealing. Once the particles have aligned in a daughter, a deprotection strand is added, removing the protection strand, and allowing annealing between strands on adjacent particles. FIG. 8 illustrates how DNA can self assemble to form a quadrilateral. Four DNA branched junctions with sticky ends self-assemble to form a quadrilateral. The sticky ends on the outside allow larger assemblies, so that one can form a 2-dimensional periodic array from the motif. FIG. 9 illustrates how stiffer antiparallel DNA double crossover (DX) molecule, with two laterally fused helices can be used to form 2D periodic assemblies, via self assembly. 9 ( a ) and ( b ) shows a schematic and actual Atomic Force Microscope Image of 4×16 nm DX tiles that contain a protruding feature yielding striped patterns of predicted separations of 32 nm (a) and 64 nm (b). 9 ( c ) is a TX (antiparallel triple helix) containing a rotated tile the sticks out on both sides. 9 ( d ) is a DNA parallelogram with 13×20 cavities. FIG. 10 a shows the machine cycle of the PX-JX2 nanomechanical device and 10 b shows a system of DNA trapezoids connected via the device that make its action visible under the AFM. FIG. 11 shows a cassette to insert the PX-JX2 device into a 2D TX array. The device is shown on the right side of the schematic in the PX conformation. The lower domain on the left inserts into a gap (19) in a 2D array. This is confirmed by the AFM image at the right. FIGS. 12 a and 12 b show a nanomechanical walking device constructed from DNA, constructed of two double helical domains held together by three loose strands. It is held to a track by two set strands. Removal and replacement of the set strands displaces the top domain to the top of the track and the bottom domain to the middle. FIG. 13 show a mechanism for attaching amino-modified DNA strands to carboxyl-functionalized microspheres. FIG. 14 shows dissociation and aggregation of a two component aggregate at 70 mM Na+. Top left: the beginning aggregate below dissociation temperature. Following the arrows, the sample is heated above the dissociation temperature (47.3 C) and allowed to cool. FIG. 15 . Specific and reversible aggregation. (A). Microbead surfaces grafted with oligonucleotides. A polymer brush imparts a steric repulsion between the particles and reduces the number of links that may form between them. Part of the DNA end is hidden in this layer of thickness h (B) Specific aggregation. Green beads are specifically linked to red, R-type beads as shown by fluorescent microscopy. (c) 23 C, reversible aggregration observed by means of bright field microscopy of particles stabilized in F108 solution observed 8 hours after mixing G and R beads (D) After raising the temperature to 50 C, the beads completely redisperse. FIG. 16 represents the surface of a colloid bead to which is attached the DNA linker and a variety of polymer brushes to stabilize the interaction with other particles. FIG. 17 Fraction of single unbound beads vs. temperature. Discrete marks are the experimental data plotted for four different stabilizers. FIG. 18 Directed assembly of particles. Flourescent and nonflourescent particles bear complementary strands of DNA. (A) Particles are first captured in discrete time-shared traps induced by laser tweezers (B-D) Particles are moved in contact to promote hybridization between the DNA strands and for the following rigid structures: a rectangle (B), a full P (C), and an empty P (D). FIG. 19 shows clusters ranging in size from 2 to 11 spheres, in various shapes. FIG. 20 Colloidal atoms. SEM images of colloidal atoms with symmetrically-placed patches on their surfaces. The number of patches n is indicated in the upper left corner of each image. The number of patches corresponds to the number of spheres that served as seeds for making these particles (as shown in FIG. 19 ). The scale bar in the lower right hand corner of the n=7 is 1 μm. FIG. 21 shows how a photonic crystal can be built by replicative assembly from a specifically constructed seed comprising structural elements, a fluorophore and photoactive quencher. FIG. 22 shows the resulting photonic crystal, in which the spacing of fluorophores and quenchers in space can be strictly controlled. Current techniques of crystal manufacture lack this control, and fluorophores and quenchers are distributed randomly. FIG. 23 shows the kinetics of particle aggregation over time at different temperatures. FIG. 24 shows the effect kinetics of particle aggregation over temperature. FIG. 25 shows aggregation of particles containing palindromic ends FIG. 26 Intraparticle bonding versus interparticle bonding can be controlled by the rate of temperature quenching. FIG. 27 Magnetic beads with a palindrome, and behaviour in response to variations in magnetic flux density (B), and temperature (T). Tm is the melting/annealing point of the complementary DNA strands. FIG. 28 AFM of a linear seed with a palindromic sequence in a bath of particles with complementary sticky ends, forming daughter strands. Diagrams illustrate the problem of particle seed interactions in which the singlet particles prefer to reside in the interstices of the seed, and bind to two adjacent particles. This results in disruption of the correct spacing of the particles in the daughter strand. One solution is to provide at least 3 different beads (flavors) so that there are no favorable interstices. Another solution is to assemble the complementary daughter strand in linear manner, relying on the previous correct positioning of the precending particle in the daughter strand. FIG. 29 illustrates schematically conventional and self-protected DNA-mediated interaction schemes including inter- and intra-particle DNA hybridization associated with the different experimental interaction schemes; interaction scheme 1a-1b involves a normal, secondary-structure free pair of complementary sticky ends, either grafted to separate beads (1a) or mixed on the same bead (1b); interaction scheme 11 used a self-complementary, or palindromic, sticky end; besides self-protective loops, this sequence can form two different hairpin structures: hairpin 1 involves only the sticky end sequence, whereas hairpin 2 forms between the sticky end and the backbone (for both T m ≈34° C.); interaction scheme 111 consisted of a Watson-Crick pair on separate beads, where each of the sticky ends can form its own protective hairpin (T m ≈43-45° C.). Figure discloses SEQ ID NOS 8-14, respectively, in order of appearance; FIGS. 30 a and 30 b show association-dissociation kinetics for conventional and self-protected interactions; FIG. 30 a is a plot of the temperature (in red) and the corresponding particle singlet fraction (symbols) as a function of the elapsed time, for conventional interaction scheme 1a; the solid red line and black dots correspond to the slowest temperature quench; the dashed red line and blue triangles correspond to the fastest quench; the microscopy insets show a small part of the sample; FIG. 30 b shows a particle singled fraction as a function of time for self-protected interaction scheme 11 and a fixed temperature profile, but at different overall particle concentrations (c=1.0 corresponds to ˜2.8×10 11 particles per square meter); FIGS. 31 a and 31 b show temperature response and proximity response of the switchable self-protected interactions. FIG. 31 a shows a fraction of aggregated scheme 11 particles as a function of time at different temperatures; the inset shows the characteristic aggregation times τ (black dots), obtained by fitting the data with the Smoluchowski aggregation equation, f bound (t)=1−(1+t/τ) −2 ; the τ values for conventional interaction scheme 1a are also shown (green squares); the error bars are approximately the size of the symbols; FIG. 31 b shows a plot of the fraction of scheme 11 particles that remained bound after keeping them close together in a weak magnetic field (˜1 mT), for different field exposure times (horizontal axis) and temperatures; the inset shows the characteristic association time r (black triangles), as obtained from first-order kinetics, f bound (t)=1−exp (−t/τ); the diffusive aggregation times of the scheme 11 beads in a are reproduced in grey; and all error bars result from the uncertainty in the singlet fraction obtained from image analysis; FIGS. 32 a - 32 i show directed assembly using self-protected interactions as a ‘nano-contact glue’; FIG. 32 a shows a microscopy image of scheme 11 particles in a circular array of optical traps, at high temperature (T≈27° C.); the black arrow indicates a displacement of the array, causing the release of two accidentally formed doublets (red arrows); Inset: Example of the disordered clusters that were obtained at high temperature in a rotating ring trap; FIG. 32 b shows as in FIG. 32 a , but at low temperature (T≈20° C.); displacement of the array releases superfluous particles from doubly occupied traps (red arrows), without forming unwanted doublets; Inset: a properly formed ring structure from a rotating ring trap at low temperature. FIG. 32 c shows after 20 min at 27° C., multiple suspension particles stuck to the previously assembled ring structure (red arrows); FIG. 32 d shows this does not happen at low temperature (20° C.). FIGS. 32 e and 32 f ( 1 and 2 ) show linear chains of scheme 11 particles, made with magnetic traps, were kept for 20 min at T=40° C. ( FIG. 32 f ( 1 and 2 )); FIG. 32 g ( 1 and 2 ) shows the results of a similar experiment with conventional sticky ends, which cannot form protective secondary structures; FIG. 32 h ( 1 and 2 ) shows a linear chain of scheme 11 particles was isolated and transferred to a new suspension of the same particles, after which it was kept inert for a prolonged time at low temperature (20° C.); FIG. 32 i ( 1 and 2 ) shows the results of a similar transfer experiment with conventional DNA-functionalized particles; and the original chain is shown in red; in all images, the particles were ˜1.0 μm in diameter; and FIGS. 33 a - 33 e show experimental and modelled association-dissociation kinetics; FIG. 33 a shows experimentally recorded particle singlet fraction (dots) as a function of time for self-protected interaction scheme 11 and different temperature ramps (in blue); the red lines show the fits from our theoretical model. FIG. 33 b shows our nomenclature for the different hybridization possibilities on an isolated scheme 11 bead (1) and for two such beads in contact (2); FIG. 33 c shows calculated bond distributions on an isolated scheme 11 bead, as a function of temperature; FIG. 33 d shows in FIG. 33 c , but for two beads in contact; FIG. 33 e shows a plot of the temperature (in red) and the corresponding particle singlet fraction (symbols) as a function of the elapsed time, for interaction scheme 1b of FIG. 29 ; and the solid red line and black dots correspond to the slowest temperature quench; the dashed red line and blue triangles correspond to the fastest quench. DETAILED DESCRIPTION OF THE INVENTION Self-replicating materials were created by first to constructing a single complex microscopic structural unit—a seed—with a specific internal structure, and then subjecting it to a cyclic process by which it self-replicates and produces, after a relatively short time, a macroscopic number of copies of the original. The original and its copies are designed to subsequently self-assemble into more complex structures. Self-replication and self-assembly requires that each elementary unit encode information in terms of chemical (short range, specific) and physical properties. It further requires a means to read this information, by interacting with other particles. The chemical and physical interactions then lead to recognition, specific attractions, repulsions and arrangement into specific configurations. Self-assembly and self-replication is therefore guided by information coded into elementary units or building blocks. Single atoms and simple molecules interact with each other in simple ways; lacking the rules to encode sophisticated structures, they organize in only a few simple motifs. As the units become more complex and contain more information, the number of structures they form increases. The more information that is encoded in the building blocks the more sophisticated the resulting structure. The present invention demonstrates replicative assembly of colloids to which is attached specific DNA linkers. Specific DNA chemical links and electrostatic and magnetic interactions are varied, in a cyclic process. In each cycle the pattern is recognized, copied, fused, and separated from its parent. With colloidal particles, for example, it is possible to control the information encoded in their interactions in the form of short strands of single stranded DNA molecules grafted onto their surface. The DNA molecules which are used specifically recognize complementary DNA molecules grafted to other colloids, which can be made to bind or unbind by changing the temperature. An important feature is that many different complementary DNA pairs can be grafted on different types of particles so that, for example, A type particles coated with one type of DNA can be made so that they bind only to A′ type particles coated with DNA strands complementary to those on A. Similarly, B-B′ type particles with different complementary strands on their surfaces can be prepared such that B particles stick to B′ particles but A and A′ particles do not stick to B or B′ particles. A particle or macromolecule contains, or is modified to contain, molecules that direct the interaction of said particle/macromolecule with other particles/macromolecules. Particle interactions are determined by (a) varying the molecules on a given first particle (b) varying the molecules on second and subsequent particles and (c) controlling the physical and chemical environment, and the temporal sequence to which particles interact. For example, in one embodiment, a micrometer scale (10 −6 m) seed consisting of different kinds of colloidal particles permanently is linked together into a particular identifiable motif. The seed is introduced into an aqueous bath containing an unbound stock of colloidal particles. Replication of the seed proceeds by a process of cyclic temperature and light intensity variations in which the seed is used as a template to assemble copies of itself from the bath of stock particles. After 10 doubling cycles, there is about 10 3 replicas of the original bath; after about 50 doubling cycles, there is approximately 10 14 replicas of the original seed, which would fill a liter-size container. The system is highly flexible, working effectively with different seeds and motifs designed to interact and self-assemble into different structures and devices In some embodiments, the particles/macromolecules are colloidal particles. Colloidal particles with different sizes, shapes (e.g. round, convex, elongated etc) compositions (polystyrene, other polymers, ceramics, metals, dielectric materials, glasses, biological macromolecules, etc) are known, spanning a range of physical properties. The invention is not limited to particles with similar physical properties, but is also effective with highly heterogenous seeds composed of particles with different compositions (e.g. polymers, ceramics, metals, etc) and different physical and chemical properties. Amplification of these seeds then allows for controlled separation and segregation of the stock particles from the bath. The seeds may then be used in their prepared form, or the segregated particles may be processed in different ways, to form two or three dimensional structures. The present invention functions particularly well in colloidal systems. Colloidal suspensions, which consist of micrometer-size particles suspended in a liquid (e.g. water) allow the person of ordinary skill in the art to (1) control their chemistry and interactions, (2) precisely position different kinds of colloidal particles into virtually any pattern using optical tweezer arrays, (3) label them with fluorescent dyes to observe and identify different particles under optical microscopes, and (4) because their dynamics are sufficiently slow, to track their movements, measure their interactions, and follow chemical reactions between them under an optical microscope. Thus, in developing specific self assembling units, virtually every step of the self-assembly and self-replication process can be observed in considerable detail. Colloidal systems can then be used directly, or adapted to both larger and smaller scales, down to nanometer size building blocks. The invention allow exploitation of the specificity of these DNA-mediated interactions to directly program the self-replication and self-assembly of colloids and, because different colloids can be fluorescently labeled and observed under a microscope, to monitor, visualize, and record in real time the reactions, configurations, intermediate states, mistakes, products, and competition that occur during self-assembly and replication. The colloidal system is ideal for demonstrating, understanding, and debugging any new processes. It is also a means to directly produce structures, sensors, actuators, reactors, and materials on a micrometer to macroscopic length scale. Accordingly, the processes are extended to the nanometer scale using polymers and nanoparticles to produce active structures and patterns for the submicron world. The invention introduces a new class of materials and devices built from programmed microscopic building blocks. In another aspect of the invention, depletion type forces and depletion zones can be utilized in the implementation of the self assembly and self replication of materials, including without limitation colloidal particles. The invention also provides for means to monitor errors in reproduction, and identify ways to control such errors. In some situations, errors are to be avoided. In others, errors can be advantageously used to develop new structures by a process analogous to mutation and selection seen in nature. Methods of Preparation 1. Preparation of particles. Polystyrene colloidal particles about 1 micrometer in diameter are commercially available. DNA can be attached to their surfaces by, for example: (1) by directly grafting PEG-DNA strands onto carboxylate surface groups on in-house synthesized particles or (2) by using commercially available particles functionalized with streptavidin together with biotin-terminated DNA strands that irreversibly bind to the streptavidin. Fluorescently-labeled particles can also be purchased or prepared in-house. A core-shell dying technique is then used to provide better optical resolution. Different polymer brushes are also used to suppress non-specific binding and optimize reversibility. The DNA sequences are also modified to optimize information storage. A key element is functionalizing the particles with two DNA linkers Paramagnetic cores for aligning the particles in a magnetic field, use directional, “patchy” particles for increased specificity and for branching into more complex chains. 2. Characterize single pair particle interactions, binding, and dynamics. Interactions between particle pairs can be measured directly using laser optical trapping techniques. Measurements of melting curves for different sequences and in different buffer solutions are also used to further characterize the interactions and to precisely tune the melting temperature between particles coated with various complementary sequences of DNA. The reaction kinetics, including reaction rates and particle transport are characterized using optical microscopy. Together, this suite of measurements enables optimization of the cyclic processes of assembly, binding, and melting. 3. Fabrication of seeds—particle motifs and sequences. Holographic optical traps (HOTS) are used to assemble arbitrary sequences of particles to create seeds of any desired design (i.e. a specific sequence of A and B particles). Sequences of particles in a chain are bound irreversibly by the addition of psoralen and subsequent exposure to UV light. Psoralen intercalates into DNA possessing complementary TA pairs. Psoralen is also highly absorbent of UV, and DNA-intercalated psoralen will mediate DNA cross linking in the presence of UV. Because this cross-linking results in a covalent chemical bond between complementary strands, the strands will not completely separate under conditions suitable for strand separation, like raised temperature. DNA lacking a TA pair will not intercalate psoralen and so will be resistant to UV-mediated crosslinking. Therefore, any particle can possess DNA that will cross link in the presence of psoralen, and DNA that will not. In one embodiment, the particles in a chain possess palindromic sequences which permit bonding to the same sequence on other particles. The person of ordinary skill in the art can determine the UV dosage required for fixing with psoralen and the rigidity of the chains that results. The use of magnetic particles and an external magnetic fields is also useful for arranging particles, such as by aligning them within a field, especially when the particles are in a chain. 4. Interaction of complementary particles with a seed chain. Interactions and reversible binding of single particles, with their complementary particles on a seed, occurs in a fluid containing an excess of free single particles. Most typically, temperature is used to control the rate and strength with which particles attach to one another. The person of ordinary skill in the art can determine the temperature dependence of the particle association with a seed, its kinetics, sticking time, etc. Also determinable by the person of ordinary skill is the dependence on position within the seed chain of a particle sticking to one of its complements. A magnetic field may also be used to align the single complementary particles in a line along the seed chain. Coordinate use of magnetic fields and temperature are used to control alignment and hybridization together, especially in the formation of higher order structures. Another important factor in hybridization between the seed and daughter particles is the problems of suboptimal arrangements that cause elemental defects, such as vacancies, kinks, and mispairing (nonspecific binding). Nonspecific binding and other defects are controlled by appropriate control of temperature, magnetic field, and temporal factors, as well as the design of the particles, thereby forming a daughter chain that faithfully duplicates the sequence of A and B particles on the seed. 5. Demonstration of duplication. Once daughter chains are assembled, they are permanently cross-linked by intercalation of psoralen between complementary TA pairs of DNA on neighboring particles and then exposure to ultraviolet light. UV dosage must be sufficient to cause cross linking; but excessive UV can cause undesirable damage to DNA, and particles. Once permanent links between particles in the daughter strand are formed, raising the temperature will melt the DNA bonds between the seed and daughter strands, causing the daughter seed to lift off, thereby causing the replication. 6. Exponential Growth. The final step in achieving self-replication is repeated cycling of the replication process, such that the daughter strand from process N is available as a template strand for all N+1, N+2, etc. Replication systems are monitored to measure the yield as a function of cycle number, the sensitively of replication rates, fidelity, and yield and how these depend on the replication cycle parameters, such as temperature, magnetic field, their timing (e.g. phasing), etc. 7. Competition and Evolution. Once exponential growth is achieved, evolution and mutation can be used to further optimize replicative process. For example, different seeds can be introduced, and allowed to compete for particles. Thus, it is possible to see how each seed grows, which grows faster, and whether one wins. In a similar vein, it is possible to determine how errors propagate and compete under exponential growth conditions. Errors may occur under normal operating conditions, but may be enhanced under particular conditions, for example by putting in chemicals that preferentially attack a particular DNA bond or by starving the bath of one of the components in the seed. Ordinarily, high fidelity in copying is desirable. However, the introduction of errors and subsequent evolution may be advantageously applied to develop new replicating materials. Self-Replication of DNA Coated Particles As outlined above, it is now possible to make a large number of identical strings of colloidal particles of some specific motif, say ABABBA, by starting with a single string and then making many copies using exponential growth. For a single string to maintain its integrity, the particles must be permanently linked within a single strong. However, to make copies of a string, single A and B particles from the bath must first recognize and at least temporarily bond to particles on an existing string. Once the proper sequence (ABABBA in this example) of particles from the bath has attached to an existing string, the particles in the new string are bonded together in a two stage process: first, temporarily and then, when the new string is completely formed, a signal is sent causing them to bond together permanently. All temporary bonds are formed using DNA hybridization; in some cases, these temporary bonds are augmented by attractive magnetic interactions. Permanent chemical bonds are formed using psoralen as a chemical linking agent using a scheme described below. There are several parts to the replication process. In the subsections below, we describe various parts of the process, not in the order they are used but in terms of the concepts required to comprehend the entire process. Once we have described each of the processes, we are then in a position to describe the detailed protocol by which the replication process proceeds. 1. Particle Recognition and Binding Scheme Using DNA Particle recognition is determined by chemical moieties designed to interact with a complementary moiety. As outlined above, such interaction should be both specific and reversible. The chemical interactions between strands of DNA are well understood, are reversible. DNA is also a stable molecule. Thus, in one embodiment, hybridization between strands of DNA are used to direct particle-particle interactions. The colloidal particles for our replication scheme (“Plan A”) actually consist of four different kinds of polystyrene particles, A, A′, B, and B′ distinguished by the combinations of DNA grafted to their surfaces (N.B. there are two kinds of A and two kinds of B particles). The beads have small paramagnetic particles embedded in them so that in a magnetic field of 20 mT they align into single strands. The recognition and bonding of the beads to each other are determined by the DNA sequences, colloquially referred to as “sticky ends.” Each kind of particle has two different types of DNA molecules grafted to its surface, one to facilitate bonding along a chain for string formation—longitudinal bonding—and another to facilitate bonding between different chains for copying—transverse bonding. FIG. 1 shows schematically the two types of DNA sequences suitable for use for longitudinal and transverse interactions (in an exemplary embodiment). The transverse sticky ends form a Watson-Crick complementary pair. The longitudinal sticky ends form a pair from identical sequences that are self-complementary (forming an “inverse palindrome” since the first half base-pair sequence is the complement of the second half). The longitudinal links also have A-T/T-A neighbor bonds. A small aromatic molecule, psoralen, can intercalculate between these bonds. When excited by UV radiation, it chemically bonds to the thymine (T) groups producing a permanent cross-link between the sticky ends (see lower part of FIG. 1 ). FIG. 2 illustrates schematically a set of sticky ends. There are two self-complementary palindrome sequences U and P and four other sequences in two sets of complementary pairs A-A′ and B-B′. (Here we use non-italicized symbols A, A′, B, and B′ to refer to the DNA sequences while the italicized symbols, A, A′, B, and B′ refer to the respective particles to which these DNA sequences are attached). FIG. 3 catalogs the four starting colloids that will be present in our stock bath and which will be used in the seed and daughter chain motifs. Beads A and B have palindrome U DNA sequences that bind to each other. Thus, A-A, B-B and A-B bonds can be formed by hybridization of the U palindrome DNA sequence on these “unprimed” spheres, thus enabling “longitudinal” bonding. These bonds can be made permanent with psoralen and ultraviolet exposure. There is also a distinct P palindrome DNA sequence attached to the A′ and B′ particles that can similarly permanently link the “primed” particles A′-A′, B′-B′ and A′-B′. Both palindrome sequences U and P have A-T/T-A units that enable permanent bonds. The DNA sequences U and P are designed specifically to avoid U-P hybridization. A different set of DNA sequences implements recognition and reversible assembly—the transverse bonds. The Crick A sequence is attached to particles A; the complementary Watson sequence A′ is attached to particles A′. Similarly the Crick B and complementary Watson B′ sequences are attached to their respective beads, B and B′. The DNA sequences U and P do not hybridize with each other and the DNA sequence A′ does not hybridize with the sequences B, B′, U, or P. It only hybridizes with A at temperatures above ˜15 C. This behavior is confirmed and optimized through direct measurements of the particles' temperature-dependent interactions. FIG. 4 summarizes the kinds of reversible and permanent links that can be made between the four differently functionalized colloidal particles A, A, B, and B′. In other embodiments, chemical linkages are also not limited to DNA-DNA interactions. Other nucleic acids can also be used, for example. Artificial forms of nucleic acids, such as PNA are typically more resistant to degradation by enzymes and have stronger binding to target sequences. Other reversible biological linkages can also be used, such as receptor-ligand, enzyme-substrate, etc. The binding of some proteins to a ligand can be made dependent on the presence or absence of a third molecule and thus protein-ligand interactions can be made reversible under moderate conditions of temperature, ionic strength, and pH. 2. Making the Seed Using Optical Tweezers. The first step is to make the sequence of colloidal particles that will serve as the seed. Holographic optical trapping assembles chains of particles with a random or specific ordering of the unprimed particles. For example, the “word” ABABBA can be formed. The assembly of the beads into a “word” is performed at a temperature above the melting (hybridization) temperature of all hybridizing pairs. After the particles are brought together to form the desired sequence, the temperature is lowered so that the beads link together by hybridization of the U palindrome (“longitudinal” bonding). The beads are then permanently cross-linked by psoralen under UV illumination. This word or sequence serves as the “seed” for self-replication. A holographic optical trap (HOT or laser tweezers) has the ability to control many particles (up to 1000) in three dimensions. The ability to sculpt light in three dimensions also allows for the creation of linear optical traps in which interacting particles can be captured. If there are gradients that attract the particles to the center of the line trap, then the distance between two particles is a direct measure of the particle interaction. A force distance curve can be obtained by varying the light intensity. An example of the sophistication of the assembly technique is demonstrated below. Such a holographic assembly is used to arrange DNA coated and fluorescently labeled colloidal particles into the chains, planes and more complex structures that will be the seeds for the self-replication process. It has been previously shown that, for example, 173 colloidal silica spheres can be arranged in a single plane within a three dimensional sample volume. Comparable planar rearrangements also can be implemented with a single rapidly scanned optical tweezer in a time-shared configuration or with the generalized phase contrast method. Unlike these other techniques, however, holographic trapping also can create three-dimensional structures. The holographic trapping system can stack micrometer-scale objects up to seven deep along the optical axis. In addition to arbitrary three-dimensional control, holographic traps offer other advantages for assembling templates for self-replication. HOT patterns can be more extensive than timeshared arrays that must periodically release and retrieve each trapped object. Additionally, the lower peak intensities required for continuously illuminated traps are less damaging to photosensitive samples. More importantly, individual holographic traps' characteristics can be tailored to different objects' optical properties to facilitate optical assembly of disparate materials. Extended holographic tweezers, which sometimes are called “line traps”, can be used for measuring interactions between colloidal particles, as discussed below. They differ from point-like optical tweezers by acting as one dimensional potential energy landscapes for trapped objects. In addition to their applications for aligning and assembling small objects, line traps provide the basis for a precise, versatile, and rapid method for measuring colloidal interactions. It has recently been shown that is possible to project line traps with the same holographic trapping apparatus used to create arrays of discrete traps. The technique, called shape-phase holography, provides absolute control over both the intensity and phase profiles of an extended optical trap. Unlike competing techniques, this approach creates traps with optimal axial intensity gradients, which can manipulate objects in three dimensions, away from bounding surfaces that might alter the objects' interactions. Holographic traps and line traps are also used for measuring the strength of interactions between particles, providing advantages over conventional methods. Interactions relevant for the self-organization of micrometer-scale colloidal particles typically are characterized by length scales ranging from a few nanometers to several micrometers and force scales ranging from several attonewtons to a few piconewtons. Small variations in these interactions can dramatically change a colloidal dispersion's stability against irreversible flocculation, and influence both the kinetics and dynamics of self-assembly. Therefore, accurately characterizing colloidal interactions is an integral part of designing and implementing the rules governing accurate self-replication of colloidal microstructures. In addition to the specific interactions mediated by ligated DNA, functionalized colloidal particles will also interact non-specifically, for example through electrostatic coupling, van der Waals interactions, and through solvent-mediated depletion interactions. These non-specific interactions determine the dispersions' stability and can modify both the strength and temperature dependence of intended specific interactions. Accurately assessing the colloidal pair potential is still more important and substantially more challenging in heterogeneous dispersions, where the interactions between all different pairs of particle types come into play. The innovation of holographic line tweezers and new statistical methods for analyzing trapped particles' motions can cut measurement time from days to minutes without sacrificing accuracy. This approach, moreover, lends itself to measuring interactions between dissimilar particles. This approach to measuring colloidal interactions is easily combined with microfluidic sample handling and external environmental controls. DNA-mediated interactions thus can be measured as a function of temperature and electrolyte composition to arrive at optimal conditions for self-replication. Because this method can provide quantitative results with as few as two particles, interaction measurements can be used as a guide for optimizing particle synthesis and functionalization. In addition to measuring colloidal interactions, optical tweezer measurements will be useful for assessing the mechanical properties of chemically linked assemblies of particles. This information, in turn, will be useful for designing protocols for transferring the organization of an optically assembled template to chemically amplified copies. 3. Temperature and Magnetic Field Protocol for Replicating the Seed. We now describe the replication process of the word ABABBA. The seed ABABBA is introduced into a bath of particles with a large quantity of the singlets A, A′, B, B′ present. The bath is above the melting temperature of all hybridized pairs. A weak magnetic field is applied which aligns the ABABBA seed parallel to the field. The temperature is lowered to the melting temperature for particles with one transverse bond (between a primed and its unprimed counterpart on the seed), two longitudinal bonds (between its two primed nearest neighbors), and three magnetic dipole interactions (see FIG. 6 ). At this temperature the complementary word A′B′A′B′B′A′ assembles alongside the seed and anneals, to rid the system of defects. The two chains remain aligned along the field direction. After annealing, the system is exposed to UV light which cross-links the palindromes thereby permanently fixing the daughter A′B′A′B′B′A′ sequence. The temperature is then increased above all melting and hybridization temperatures. Then, as shown in FIG. 6 , the A′B′A′B′B′A′ strand separates from the seed ABABBA forming a replica. The process of temperature change and UV exposure is then repeated cyclically. In each cycle the original and daughter cells are replicated doubling the population. This leads to an exponential population growth as long as the supply of lettered particles persists. In order to readily identify these particles under an optical microscope, these particles can also be distinguished by the fluorescent dyes they contain: a red dye for the A and A′ particles and a green dye for the B and B′ particles. 4. Hairpins in DNA Palindromes Specific DNA-DNA interactions can be determined by any two complementary sequences. The number of required complementary sequences can be reduced by the use of palindromic (self-complementary) sequences, which allow any particle to bind to any other particle. A possible problem is that palindromic DNA, at low concentration, and particularly when isolated, can form hairpins, since its 5′ end can pair with its 3′ end. This would render the DNA sequence non-reactive. One way to defend against such an eventuality is to protect the sequence. FIG. 7 illustrates protection of the ends. The drawing has three parts. Illustrated at the top is the ideal interaction. However, the possible problem of forming hairpins is illustrated below it, preventing interaction. A possible solution is shown at the bottom. The palindrome is flanked on one end by the extra sequence, drawn in green, so that it would compete favorably with the hairpin phenomenon, particularly at high local concentration. A protection strand is added (at high enough temperature to overcome any hairpins already present), preserving the system for alignment. When the particles are aligned, a deprotection strand is added according to the technique of Yurke et al. “A DNA-fuelled molecular machine made of DNA” Nature 406: 605-608 (2000). It will remove the protection strand because it has an extra portion (drawn blue) that acts as a toehold for it to bind to the protection strand and then to branch migrate it off the binding strand. The extra length of this duplex acts as a thermodynamic trap. The particles are then free to bind to each other. Other solutions to hairpin formation including changing the pH, temperature or other factors, to be unsuitable for hairpin formation until the particles are in place. This approach is explored in greater detail in FIGS. 23-27 . 5. Mis-Pairings of Primed and Unprimed Particles Mispairings may also occur. FIG. 28 , for example, shows an A′ particle heading into its intended position to across from an A particle on a parent strand (seed) and between two A particles in a daughter strand. The B′ particle makes bonds with its neighbors and is clearly in its lowest energy state. Thus, the arrangement of particles would be disrupted, resulting in a permanent error in the daughter strand that would propagate in subsequent generations. While such errors might be interesting for evolutionary studies, they might also significantly compromise the amplification process. One solution to this problem is to adjust the length of the Watson-Crick pairings for the U-U and P-P strands compared to the A′-A and B′-B strands such that the melting temperature of the U-U and P-P strands is several degrees lower than that of the A′-A and B′-B strands. Then, in the first stage of the copying process, the temperature would be lowered below the melting temperature of the A′-A and B′-B strands, but kept above the melting temperature of the U-U and P-P strands. This would allow the copying process to proceed without interference from the longitudinal bonds. Once the primed-unprimed parings between the parent and daughter strands are made, the temperature would be lowered, allowing the unprimed longitudinal pairings to occur. Exposure to UV light would then make the longitudinal pairings permanent, as before. 6. Structural Control of DNA One basic scheme for self-replication is that based on the specific and reversible hybridization interaction of complementary Watson-Crick DNA pairs. The arrangement of bases on the single stranded “sticky end” of a DNA chain is at the heart of the strength, specificity, efficiency, and robustiness of the interactions that will bind our colloidal particles. DNA sequences may be designed to produce sticky ends and many more complex structures. Work since the 1980's has shown that DNA can be used to form DNA objects and nanomechanical devices from components that are closely related to the branched DNA Holliday intermediate in genetic recombination. It is easy to design synthetic DNA molecules that self-assemble to produce stable branches. It has been that the structure of DNA in the vicinity of sticky ends is classical B-DNA (the Watson-Crick structure), so it is possible to know the detailed geometry of local product structures at the point of cohesion. Thus, if we know where the atoms are on one side of a sticky end, we know where they are on the other side. This is a key step towards making the connection between the microscopic and the macroscopic: predictable geometry enables one to program structural features on the nanometer scale. Using sticky ends to control the interactions of branched DNA molecules, enables us to construct N-connected objects and networks. For example, in FIG. 8 , a DNA branched junction molecule with sticky ends self-assembles to form a quadrilateral. Using this notion, it has been shown how to build stick polyhedra with the connectivities of a DNA cube, and a DNA truncated octahedron, where the edges are double helical DNA, and the branch points of junctions correspond to the vertices. The conventional branched junction is fairly flexible. Stronger, more rigid structures can be made with the antiparallel DNA double crossover (DX) molecule, that contains two laterally fused helices is about twice as stiff as conventional DNA. The fusion between helices is achieved by crossover of strands between the helices. DX molecules can be used to form 2D periodic assemblies, via self assembly, as shown in FIG. 9 . Triple-crossover (TX) molecules and DNA-parallelograms can also be used to form 2D periodic assemblies. DNA motifs used for filling 2D or 3D space as tiles. DNA-based nanomechanical devices have also been developed, such as the sequence-dependent PX-JX 2 device, and a bipedal walker. The nanomechanical device machine cycle is shown in FIG. 10 a . The structure on the left (PX) has wrapped itself a half-turn more than the structure on the right (JX 2 ). The green strands at the center of the PX molecule are removed by techniques described by Yurke et al., and the yellow strands can be added, to switch between states. FIG. 10 b shows that this device controls the relative orientations of DNA trapezoids, a motion that is detectable by the AFM. In a key development, we have now made a cassette that allows the insertion of this device perpendicularly into a 2D) array, as shown in FIG. 11 . This motion is also detectable by AFM. The development of this cassette will enable us to couple devices with arrays, and will lead to the development of nanorobotics, independently moving devices at fixed places in space. Another device known in the art is a biped designed to walk on a track, as shown in FIG. 12 , originally described in Sherman and Seeman, “A precisely controlled DNA bipedal walking device” NanoLetters 4: 1203-1207 (2004). The device is based on the notion that one can move each of its parts individually. Thus, the top domain of the ochre device is released from the blue track by removal of the set strand holding it there, and then addition of a new set strand enables it to latch on to the top domain. The flexible strands holding the two domains together enable it to stretch that distance. The bottom domain is moved to the middle domain in the same way. 7. Colloidal Interactions Using DNA-Coated Particles Previous researchers had shown that specific aggregation of DNA-coated particles was possible and that some degree of reversibility could be achieved, but to be useful in a materials sense, much more control is required. The largest problem was that complementary particles would not separate when heated above the DNA melting temperature. Another force, probably van der Waals at small separations, held them together. The solution was to use a polymer brush to keep the particles out of the range of the van der Waals well while still within range of the DNA attraction. FIG. 13 shows one approach to modify the surface of a colloidal particle to accommodate a polymer spacer, PEG, and the DNA sticky end. The images in FIG. 14 show the aggregation of the colloids below the DNA melting temperature, the redispersal hence reversibility on heating and reaggregation on recooling. Another approach is to use a commercial particle with biotin-streptavidin links to attach the DNA and a separate absorbed polymer brush to prevent van der Waals interactions. A length of double stranded DNA is used to keep the sticky end more distant from the particle, and away from van der Waals forces. One of ordinary skill can, of course, adjust the length of the DNA spacer and the size of the polymer brush to control the degree to which sticky ends are accessible by other sticky ends. A schematic of the particles is shown in FIG. 15 . Here the complementary particles are dyed with rhodamine and fluorescene to fluoresce red or green. We see the specific association in that there are no direct red-red or green-green pairs. Aggregates only form from red-green bonds. The lower pictures also show the reversibility as redispersal on heating. FIG. 16 represents the surface of a colloid bead to which is attached the DNA linker and a variety of polymer brushes to stabilize the interaction with other particles. A process for self-replication requires control over the DNA melting temperature. This can be done separately by the length and sequence of the DNA sticky ends, but it also can be done by adjusting the adsorbed polymer. A set of melting curves, for different adsorbed polymers is shown in FIG. 17 . This figure also illustrates that it is possible to take quantitative thermodynamic measurements by use of confocal microscopy and imaging, and control physical parameters (such as temperature and temperature gradients). The fact that we can fabricate seeds by particle manipulation using optical tweezers is illustrated in FIG. 18 where DNA coated particles are positioned, brought together and bound into a few patterns. 8. Colloidal Clusters and Patchy Particles “Colloidal molecules” or “colloidal clusters” refers to any one of a variety of clusters made from colloidal spheres irreversibly linked together at one or more points; these clusters have well-defined shapes and include dumbbells (dimers), triangles (trimers), tetrahedra (tetramers), and octahedra (hexamers), as well as many more exotic clusters. FIG. 19 shows clusters ranging in size from 2 to 11 spheres. With the techniques developed in Pine's group, it is straightforward to produce more than a billion clusters of a given number per batch. See, e.g. Cho et al. “Self-organization of bidisperse colloids in water droplets,” J. Am. Chem. Soc. 127: 15968-15975 (2005). The second class of particles are made from the colloidal clusters and consist of particles that are nearly spherical but have a finite number of small chemically distinct patches on their surface. SEM photographs of particles with 2-7 patches are shown in FIG. 20 . These patches can serve as centers for creating bonds along well-defined directions to other colloidal particles, much as atoms do; we call these particles “patchy particles” or alternatively “colloidal atoms.” Like conventional atoms and molecules, each of the colloidal atoms and molecules possess well-defined symmetries: for a given number of particles or patches n, all colloidal molecules are identical, as are all colloidal atoms of a given n. The middle patchy particle in the bottom row is especially interesting in the present context. It has 6 patches. Thus, if we assembled a string of such particles in a straight line and connected them to each other by opposing patches, which would leave four exposed patches on each particle along the string where other particles could attach laterally. 9. Industrial Applications Success in creating a self-replicating system with polystyrene beads can be translated to a wide range of materials, such as metals and ceramics, semiconductors and plastics. Such composite, microscopically-designed, materials should find wide application as sensors, solar cells, battery and fuel cell components, as well as new materials for personal products and pharmaceuticals. FIG. 21 shows how a photonic crystal can be built by replicative assembly from a specifically constructed seed comprising structural elements, a fluorophore and photoactive quencher. FIG. 22 shows the resulting photonic crystal, in which the spacing of fluorophores and quenchers in space can be strictly controlled. Current techniques of crystal manufacture lack this control, and fluorophores and quenchers are distributed randomly. The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention. The following non-limiting Examples are illustrative of various aspects of the invention. Example I Demonstration of Self-Replication of a Non-Biological System An easily identifiable single seed of fluorescently is labeled red A and green B type spheres, and is permanently linked in a sequence, say ABABBA. The seed is introduced to a system of stock A, B, A′ and B′ spheres and cycle the physical and chemical environment, causing a new complementary sequence A′B′A′B′B′A′ of colloidal spheres to form. After one cycle a duplicate is observed, after two cycles four copies, and after N cycles 2 N copies. Observation of another seed, say AAAABBAAA, and exponential growth, demonstrates self-replication. Control of particle interactions is an important factor. The temperature at which complementary strands of DNA anneal and which they melt is typically for a large population of DNA (i.e. the average temperature of annealing and melting). For small amounts of DNA on particles, particle association and dissociation may occur at different temperatures, in part due to kinetics. Seee Crocker Proc. Natl Acad Sci USA 102: 4225 (2005). FIG. 23 shows the kinetics of aggregation of DNA-coated beads as a function of temperature and time. A pool of particles was cycled through temperatures up to 44 C (the melting temperature), and then rapidly cooled. When rapidly cooled many centigrade below the melting temperature, aggregates formed that survived until the temperature was raised to 44 C. The difference between the temperature at which the beads are allowed to aggregate is progressively raised. The left hand side shows that aggregates will reversibly form and then dissociate, through changes in temperature, when the temperature is sufficiently different from the melting temperature. However, as shown in the right hand side, as the aggregation temperature approaches the temperature of melting, the aggregation kinetics are inhibited and many aggregates to not form. This information is important for determining the temperature at which aggregates form. The reverse process is useful for demonstrating the temperature at which aggregates will dissociate. FIG. 24 shows the effect kinetics of particle aggregation over temperature. The aggregation temperature and melting temperatures, and their difference, is important for controlling the association and dissociation of particles. If the two temperatures are close (a low “width”) then small changes in temperature can be used to reversibly control particle-particle interactions. A particle with palindromic ends can bind to any other particle with the same palindromic ends. Thus, the number of sticky ends required to facilitate particle-particle interactions is lessened, compared to what would be required if non-palindromic ends are used. The downside, however, is that palindromic DNA can self hybridize, forming hairpins. It can also hybridize with adjacent molecules of the same DNA in the same molecule (intraparticle bonding), which competes with interparticle bonding. ( FIG. 26 ). Palindromic interactions can be minimized by the use of protection strands (Yurke techniques), however, the use of protection strands creates extra complexity to any synthetic process. Alternative approaches to control disfavored palindrome DNA interactions are explored in experiments which are illustrated in the following figures. For a palindrome to form a hairpin, the DNA must bend in on itself. Similarly, for DNA to form intraparticle hybridization, the DNA must bend. Because bending requires extra energy, hairpin formation and intraparticle hybridization therefore requires more energy than interaction between two linear stretches of DNA, such as interparticle hybridization. The ability of DNA to deform may be measured by its persistence length. Increasing the persistence of the DNA (and the stiffness therefore) makes intraparticle interactions less favorable. Accordingly as shown in FIG. 25 , the use of a 60 bp DNA containing a double stranded 50 bp segment has a persistence length of 50 nm, which is longer than the length of the double stranded portion. By contrast, a 60 bp single strand has a persistence length of less than 5 nm. Temperature is also an important factor in controlling the relative proportion of interparticle versus intraparticle/hairpin formation. The graph at the bottom of FIG. 25 shows an experiment measuring the number of singlet (isolated particles) in a pool of particles with palindromic DNA surfaces. At low temperature, intraparticle/hairpin formation is favored, resulting in less free ends to interact with another particle. As the temperature is raised, the energetically disfavored intraparticle and hairpin hybridizations are reduced, in favor of interparticle hybridization, and therefore resulting in the formation of clusters of particles, as the number of singlets drops. Raising the temperature further, however, results in melting of the particles. The kinetics of inter- and intraparticle hybridization is also usefully employed, as shown in FIG. 26 . In the experiment, aggregates melt at 46 C. If the temperature is rapidly reduced to 14 C in less than 150 s (fast temperature quench), the vast majority of particles remain as singlets. By contrast, a slow (250 s) drop to 31 C (slow temperature quench) results in fewer singlets, and more particles. Beads can be arranged by multiple means. FIG. 27 shows how magnetic beads with a palindromic DNA interact in response to variations in magnetic flux density (B), and temperature (T). T m is the melting/annealing point of the complementary DNA strands. When B is raised, but above the melting point, the beads form chains along the lines of the magnetic field. If the field is turned off, the chain dissociates. If the field is then reactivated above T m , and then the temperature lowered to below T m , the beads will form a chain that remains when B=0. When T is again raised, the chain dissociates. This experiment demonstrates that the magnetic field can be used to organize the beads, and the temperature is modulated to fix the beads in relationship with each other even in the absence of the magnetic field. This DNA-mediated interaction is fully reversible by changing the temperature. It was then demonstrated that the DNA-mediated interaction could be made irreversible through the use of psoralen and UV. Beads with the palindrome TACAGCTGTA (SEQ ID NO: 5) aggregate below T m , and the aggregation is reversible by raising the temperature. However, if the beads are allowed to aggregate in the presence of psoralen, and then exposed to UV, subsequent elevation of the temperature will not cause disaggregation, because the DNA between adjacent particles has been crosslinked. By contrast, beads with the palindrome CCAGCTGG formed reversible aggregates below T m , but exposure to psoralen and UV did not result in permanent aggregates, because the palindrome does not contain an AT pair which is necessary for psoralen and UV to cross link the DNA. In another experiment, a chain of magnetic beads formed under the influence of a magnetic field were then annealed (by lowering the temperature) and crosslinked with psoralen/UV treatment. These particles, bearing a nonpalindromic sequence, specifically interacted with nonmagnetic particles bearing the complement, as shown in FIG. 28 , based entirely on DNA interactions. However, there is a problem of particle seed interactions in which the singlet particles prefer to reside in the interstices of the seed, and bind to two adjacent particles. This results in disruption of the correct spacing of the particles in the daughter strand. One solution is to provide at least 3 different beads (flavors) so that there are no favorable interstices. Another solution is to assemble the complementary daughter strand in linear manner, relying on the previous correct positioning of the preceding particle in the daughter strand. Another, related, solution is to have the strand possess elements of directionality, similar to that seen in DNA replication. Patchy particles, which do not possess a uniformly coated surface, can be used to provide directionality to the chain. Surface functionalization using DNA can be a very useful mechanism for guiding the self-assembly of nano- and micrometer-sized particles. Complementary ‘sticky ends’ can form specific interparticle links and reproducibly bind at low temperature and unbind at high temperature. The ability of single stranded DNA to form folded secondary structures has not been investigated for controlling (nano) colloidal assembly processes, despite its frequent use in DNA nanotechnology. In this example is illustrated the mechanism to carry out loop and hairpin formation in the DNA coatings of micrometer-sized particles which gives us in situ control over the inter-particle binding strength and association kinetics. This methodology can be finely tuned and even the attractions switched off between particles, rendering them inert unless they are heated or held together in the manner of a nano-contact glue. The kinetic control offered by the switchable self-protected attractions is explained with a simple quantitative model (non-limiting explanation) that emphasizes the competition between intra- and inter-particle hybridization. Practical utility is demonstrated by the assembly of designer clusters in concentrated suspensions. With self-protection, both the suspension and assembly product are stable, whereas conventional attractive colloids would quickly aggregate. This functionality makes our self-protected colloids a unique material that greatly extends the utility of DNA-functionalized systems, enabling more versatile, multi-stage assembly approaches. Example II The particle association and structural organization of DNA functionalized systems are equilibrium processes that depend solely on the system temperature, relative to the particles' DNA-dependent dissociation temperature. This is, for instance, demonstrated by our observations on mixtures of beads that form normal Watson-Crick pairs of complementary C N /C′ N sticky ends (interaction scheme Ia, see FIG. 29 ). FIG. 30 a shows the fraction of non associated particles, or singlet fraction, as a function of time in an experiment where the temperature was decreased from 52 to 20° C. (t<810 s) and then ramped back up (t>810 s). Clearly, as soon as we go below the particles' dissociation temperature (T dis ≈40° C.), the singlet fraction quickly drops to zero, and the particles come together in extensive structures. Conversely, when we increase the temperature above T dis the aggregates quickly dissociate. The rate of temperature change determines how fast T dis is reached, but it does not change the qualitative shape of the curves. Much more flexibility is gained if the sticky ends possess secondary conformations, such as hairpins and loops due to intra-particle complementarity (for example, interaction scheme II, FIG. 29 ). Such secondary structures form in fractions of a microsecond, as estimated from the rotational diffusion time of single stranded DNA with an end-to-end distance of ˜14 nm. This should be compared with the association time of the particles, which depends on their diffusion constant and concentration, and which is of the order of minutes for micrometer-sized beads. As long as the secondary structures have smaller binding energies than the inter-particle bridges, particle association should in principle still be possible. However, in a fast temperature quench, extensive secondary structure formation will occur inside the DNA coatings of the individual beads before they encounter each other. Here, we explore the in situ control that this self-protection mechanism offers over the number of sticky ends available for inter-particle bridging which is one of the main parameters that determine the particles' association strength and kinetics and the new possibilities that this offers for the assembly of designer structures. FIG. 30 b demonstrates that it is indeed the competition between the quench rate and the particles' diffusive encounter rate that matters. Unlike conventional DNA-functionalized particles (see FIG. 30 a ), a fast temperature quench consistently arrests the aggregation of self-protective scheme II particles at a non-zero singlet fraction, which is higher for smaller particle concentrations (in FIG. 30 b is shown a series of horizontal plateaux). The occurrence of aggregation followed by inactivation indicates that at the start of the quench inter-particle bridges dominate, whereas at lower temperatures intra-particle loop and hairpin formation reduce the number of unprotected sticky ends, to the point that it arrests the aggregation. At lower particle concentrations, fewer associative collisions occur before the interactions are completely inhibited, giving a higher plateau. The difference in the melting temperatures of the loops and inter-particle bridges, the former being lower than the latter, is due to the different configurational entropy costs associated with these two hybridization geometries. Apparently, the particles' diffusive encounters, estimated to last ˜0.2 ms, are too short for the low-temperature loops and hairpins to open up and to form more stable inter-particle bridges. From FIG. 30 b , it can also be seen that when the temperature is increased again (t>400 s), dehybridization of the loops and hairpins reactivates the particle association, leading to a dip in the singlet fraction before the beads enter the familiar dissociation transition. In addition to the quench rate/concentration dependence, FIGS. 31 a and 31 b highlight two other important properties of our self-protected colloids. First, FIG. 31 a shows the pronounced temperature dependence of the association kinetics in an experiment where we monitored the diffusive aggregation of scheme II beads at several different temperatures. From the inset, it is clear that the temperature response of these self-protective beads is much stronger than that of conventional scheme Ia beads. This results from the fact that the sticking probability of the self-protective beads depends on the fraction of unprotected sticky ends, which changes exponentially with the temperature, f u α exp (ΔG DNA /k B T) (here, ΔG DNA represents the hybridization free energy of the protective secondary structures). For conventional beads, all sticky ends are always unprotected, making their association kinetics only weakly temperature dependent. Second in FIG. 31 b , we determined the fraction of scheme II particles that remained bound, after keeping them close together in chain-like structures, induced by a weak magnetic field. The inset shows that the association kinetics again speed up with the temperature, but that the timescales are three orders of magnitude shorter than the ones associated with diffusive aggregation. This is because by keeping the particles in each other's proximity, the field allows for multiple binding attempts without slow, long-distance particle diffusion in between. Taking advantage of the special properties of our self-protected colloids, we can overcome some of the main limitations of conventional DNA-functionalized systems. As an example, we demonstrate the directed assembly of ring-like structures, using interaction scheme II and holographic optical traps ( FIGS. 32 a to 32 d ). We either shrink a circular array of point-like traps until the particles are in close proximity (stationary trapping) or we use a continuous, rotating ring trap in which the particles can freely move around (dynamic trapping). At high temperature, but well below the particles' dissociation transition, the self-protection is limited and the suspension behaves like a conventional DNA-functionalized system. This means that any positioning mistakes that occur while the particles are being arranged into the desired structure (the pre-assembly stage) immediately cause particles to stick in the wrong place. For instance, accidentally trapping two particles in the same stationary trap creates doublets ( FIG. 32 a ), whereas dynamic trapping yields only disordered clusters ( FIG. 32 a ). In contrast, at low temperature the sticky ends are well protected, providing ample time to correct any positioning mistakes in the pre-assembly stage ( FIG. 32 b ). The particles inside the structures spontaneously bind together or can be triggered to do so by a brief elevation of the temperature. It follows from FIG. 31 that the temperature can be chosen such that the structures crosslink in ˜5-10 min, and the diffusive aggregation is negligible for many hours. Thus, whereas at high temperatures the newly assembled structures soon aggregate and become decorated with other particles ( FIGS. 32 c and 32 e ), at low temperatures the structures and surrounding suspension are nearly inert ( FIGS. 32 d and 32 f ). These experiments also demonstrate that we can deliberately switch the association on and off without dissociating the previously assembled structures. Clearly, our self-protected particles greatly facilitate the fabrication of designer structures that are inert to further association, without the need to work under dilute conditions. Moreover, it enables multi-stage assembly approaches in which previously formed structures can for instance be isolated, transferred to a new particle suspension and kept stable for a prolonged time ( FIG. 32 h ). These properties stand in sharp contrast to those of conventional DNA-functionalized systems that can switch only between fully associated and fully dissociated states. As is demonstrated by FIGS. 32 g and 32 i , the latter means that any newly assembled structure of conventional DNA-functionalized particles will be subject to rapid and uncontrollable aggregation, which compromises their practical use. A quantitative understanding of the self-protection can be obtained by modelling a series of association-dissociation curves that were obtained at different quench rates ( FIG. 33 a ). Here, we outline the main principles; more details will be presented elsewhere. In its simplest form, we treat the particle association and dissociation as a reaction that interconverts singlets (S, concentration c 1 ) and doublets (S2, concentration c 2 ): This reaction is governed by the rate equations: ⅆ c 1 ⅆ t = - 2 ⁢ k on ⁢ c 1 2 + 2 ⁢ k off ⁢ c 2 ⅆ c 2 ⅆ t = - k on ⁢ c 1 2 - k off ⁢ c 2 In the experiments of FIG. 33 a , each time t corresponds to a particular temperature, T(t). The association rate parameter, k on , depends on the diffusive flux of singlets, in two dimensions k diff =2k B T(t)/3ηR p (k B is the Boltzmann constant, η is the viscosity and R p is the particle radius), and the dissociation rate parameter follows from the free energy for bead-bead hybridization, k off (t)α exp(ΔF bead /k B T). The horizontal plateaux in the experimental aggregation curves indicate that the conversion of loops and hairpins into inter-particle bridges occurs on a timescale that is significantly longer than the duration of a diffusive particle encounter. Moreover, by the time two particles encounter each other, a hybridization equilibrium will have been established inside their DNA coatings. Therefore, we assume that in the early stages of association, ΔF bead is determined by the fraction of unprotected sticky ends at the moment of collision, which follows from the partition function of all of the different hybridization possibilities on an isolated particle, Supplementary Equations S1-S3 and schematic diagram 1, (see FIG. 33 b ). Using the predicted solution hybridization free energies, ΔG 0 (see the Methods section), and including an appropriate configurational entropy cost, ΔS conf , for the loops (ΔG loop =ΔG p 0 ,solution−TΔS conf,loop ), we find the bond distributions in FIG. 33 c . Taking the fraction of unprotected sticky ends, f AU , we obtain ΔF bead from the expression that has been previously published for two surfaces that interact with a certain fixed number of active sticky ends: Δ ⁢ ⁢ F bead k B ⁢ ⁢ T = - ln ⁡ ( [ 1 + f AU ⁢ m ⁢ ⁢ exp ⁡ ( - Δ ⁢ ⁢ G bridge k B ⁢ T ) ] f AU ⁢ N b - 1 ) Here, N b is the maximum number of bridges that can form if all sticky ends are unprotected, m is the number of opposing sticky ends within reach and (ΔG bridge =ΔG p 0 , solution−TΔS conf,bridge ). To model the particles' high-temperature dissociation transition (t>>810 s in FIG. 33 a ) we follow a similar approach, but now we consider the equilibrium that includes intra- and inter-particle hybridization simultaneously, because the particles inside the aggregates are in prolonged contact, enabling the interconversion of loops, hairpins and inter-particle bridges. The total partition function and ΔF bead are then applied (see FIG. 33 b ), and FIG. 33 d shows the bond distributions. Finally, we fit the experimental data by numerically solving for the evolution of the rate equations (equation (1)), using the experimental singlet concentration at t=0 and temperature profiles, T(t), as input. Keeping all other parameters fixed at their known or estimated values, we obtained the fits in FIG. 33 a with the configurational entropy costs ΔS conf,bridge =12.6 k B and ΔS conf,bridge =13.5±0.2 k B . We have previously shown that these values agree fairly well with those obtained from simple geometrical estimates. Moreover, the computed curves show the expected strong dependence on the quench rate. FIG. 33 c indicates that for interaction scheme II the main contribution to the self-protection comes from loop formation. We verified this with a system in which the normal C N and C′ N sticky ends were mixed in a 50=50 ratio on the same bead, giving loop formation, but no hairpins (interaction scheme Ib, FIG. 29 ). FIG. 33 e shows that in broad lines the association-dissociation behaviour for this system is indeed similar to that of scheme II. However, the C N /C′ N system suffers from a ‘pairing’ problem, in that a certain fraction of sticky ends fails to find a nearby partner for loop formation. This prevents a complete arrest of the aggregation, hence the tilt of the plateaux in FIG. 33 e . Apparently, the seemingly insignificant hairpin formation of scheme II has an important role in circumventing the pairing problem, as the mono-molecular hairpins protect sticky ends that remain without a binding partner. We also point out that similar switchable self protected interactions can be established with sticky ends that formonly hairpins and that have no intra-particle complementarity, such as, for instance, the C H /C′ H pair of interaction scheme III ( FIG. 29 ). In summary, we have added secondary structure formation to the DNA toolkit that facilitates the (self-)assembly of nano- and micrometer-sized particles, and we have developed a non-limiting example model that provides a quantitative understanding of the particle association. Besides facilitating the fabrication of designer structures, the self protected interactions will impart selective, self-healing and self reinforcing properties to the particle assemblies. Selective, because particles only connect if held sufficiently long in the right position; here done with optical or magnetic traps, but other methods, such as templating, are conceivable as well. Self-healing, because the material can be broken into smaller, stable pieces that nevertheless have the ability to reconnect. Self-reinforcing, because the initially weak bridging may be followed by the formation of more bonds through the opening of intra-particle loops and hairpins, either spontaneously or triggered by heat. The last property is reminiscent of certain forms of cell adhesion, where rapid capture is followed by slow consolidation, and, together with the other functionalities, this will enable more complex assembly schemes. Several methods of DNA and particle preparation are now described herein. All of our DNA constructs consisted of a highly flexible, single-stranded backbone of 50 nucleotides long with a short, 8-11 nucleotides long single-stranded sequence at its 3′ terminus. The C N /C′ N and P oligonucleotides were purchased from Integrated DNA Technologies USA, whereas we synthesized the C H /C′ H sequences ourselves, on an Applied Biosystems 394 DNA synthesizer. After completion, we removed the oligonucleotides from the support and deprotected them using conventional phosphoramidite procedures. The backbone of the DNA constructs was attached to a 50 biotin group through a short, flexible polyethyleneglycol spacer. For most experiments, we functionalized 1:05 μm diameter, streptavidin-coated, paramagnetic polystyrene Dynabeads (MyOne Streptavidin C1, Molecular Probes) with the biotinylated DNA constructs, by incubating 5 μl bead suspension for 30 min at 55° C. with 5 μl of 6 μl 41 oligonucleotide solution and 65 μl suspension buffer (10 mM phosphate/50 mM NaCl and 0.5% w/w Pluronic surfactant F127, pH 7.5). Strong sedimentation of these high-density particles quickly led to essentially two-dimensional microscopy samples. For the optical trapping experiments, we used 1:0-μm-diameter, non-fluorescent, neutravidin-labelled polystyrene Fluospheres (Invitrogen), combining 5 μl bead suspension with 10 μl oligonucleotide solution and 85 μl suspension buffer. These particles had a density close to that of water and remained suspended throughout the entire sample for many hours. In all cases, we removed excess and non-specifically adsorbed DNA by centrifuging and resuspending the particles three times in 100 μl suspension buffer; we repeated this washing procedure twice, heating in between for 30 min at 55° C. Regarding the thermodynamic parameters of the oligonucleotides, we obtained the enthalpic and entropic contributions to the hybridization free energies (ΔG 0 =ΔH 0 −TΔS 0 ) of the sticky ends and their secondary structures from the Mfold webserver, using [Na + ]=68 mM for the suspension buffer. C N /C′ N : ΔH 0 =370 kJ mol −1 , ΔS 0 =1.08 kJ mol −1 K −1 : P; ΔH 0 =−296 kJ mol −1 , ΔS 0 =841 J mol −1 K −1 ; P hairpin 1: ΔH 0 =84.9 kJ mol −1 , ΔS 0 =−267 J mol −1 K −1 ; P hairpin 2; ΔH 0 =−148 kJ mol −1 , ΔS 0 =−472 J mol −1 K −1 ; C H /C′ H : ΔH 0 =−285 kJ mol −1 , ΔS 0 =−798 J mol −1 K −1 ; C H hairpin: ΔH 0 =−81.6 kJ mol −1 , ΔS 0 =−258 J mol −1 K −1 ; C′ H hairpin: ΔH 0 =−71.1 kJ mol −1 , ΔS 0 =−223 J mol −1 K −1 . DNA-functionalized particle suspensions are confined to a borosilicate glass capillary (inner dimensions 2:0×0:1 mm, Vitrocom), which was previously cleaned by oxygen plasma etching and hydrophobized by silanization. The capillary was then mounted on a special stage set-up on a Leica DMRXA light microscope, which enabled fine temperature control, while imaging in a conventional transmission mode. To study the association kinetics in the presence of a magnetic field, we centred the iron cores of an electromagnet coil (made in-house) around the microscope objective. Temperature-regulated holographic optical trapping set-up. For optical trapping, 10 μl of DNA-functionalized particle suspension was sealed between two 18×18 mm 2 , number 1 cover slips, which were previously cleaned by oxygen plasma etching and hydrophobized by silanization. The sample then was mounted on a sapphire microscope slide and centred on a 14.5-mm-diameter hole passing through a water-cooled Peltier element (Melcor, series SH 1.0-95-06). This enabled us to control the sample's temperature while simultaneously providing optical access for transmission-mode imaging and optical micromanipulation. Holographic optical traps were powered by a frequency-doubled diode-pumped solid-state laser (Coherent Verdi), operating at a wavelength of 532 nm. A reflective liquid crystal spatial light modulator (Hamamatsu X8267-16 PPM) imprinted the beam's wavefronts with computer-generated holograms encoded with the desired trapping pattern. This laser profile was then directed into the input pupil of a ×100, numerical aperture: 1.4, Plan Apo oil-immersion objective mounted on a Nikon TE-2000U inverted optical microscope, and was focused into optical traps. All of the compositions and methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the methods described herein without departing from the concept, spirit and scope of the invention. More specifically, it will be apparent that certain agents that are chemically or physiologically related may be substituted for the agents described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention.

The invention provides micron and sub-micron scale particles designed to recognize and selectively interact with each other by exploiting the recognition and specificity enabled by DNA-sequence-encoded coatings. Such materials possess sufficient information coded in their chemical and physical interactions to self assemble and self replicate. The invention further provides methods of using such materials to create self replicating and organizing materials. Replicated copies are permanently linked and then thermally detached, freeing them to act as templates for further growth. This new class of condensed matter systems, provides means to design and control the structure and function of materials and machines from the microscopic to life-size. In another aspect of the invention, depletion type forces and depletion zones can be utilized in the implementation of the self assembly and self replication of materials, including without limitation colloidal particles. The invention further provides novel means of synthesis and materials built by such synthesis, which may be used in a variety of applications, including microelectronics.

CROSS-REFERENCES TO RELATED APPLICATIONS The present application is a continuation of co-pending U.S. patent application Ser. No. 13/205,115, to Graves et al., entitled “OPTICAL SWITCH WITH POWER EQUALIZATION,” filed Aug. 8, 2011, which is a continuation of U.S. patent application Ser. No. 12/476,693, to Graves et al., entitled “OPTICAL SWITCH WITH POWER EQUALIZATION,” filed Jun. 2, 2009, which issued as U.S. Pat. No. 7,995,919 and which is a divisional of U.S. patent application Ser. No. 09/580,495, to Graves et al., entitled “OPTICAL SWITCH WITH POWER EQUALIZATION,” filed May 30, 2000, which issued as U.S. Pat. No. 7,542,675, all of which are assigned to the assignee of the present invention, and all of which are hereby incorporated by references herein in their entireties. The present application is related in subject matter to U.S. Pat. No. 6,606,427 B1 to Graves et al., entitled “SWITCH FOR OPTICAL SIGNALS,” issued Aug. 12, 2003, assigned to the assignee of the present invention and hereby incorporated by reference herein in its entirety. The present application is also related in subject matter to the U.S. Pat. No. 6,871,021 B2 to Graves et al., entitled “OPTICAL SWITCH WITH CONNECTION VERIFICATION,” issued Mar. 22, 2005, assigned to the assignee of the present invention and hereby incorporated by reference herein in its entirety. FIELD OF THE INVENTION The present invention relates generally to systems used for switching optical wavelength channels in a wavelength division multiplexed (WDM) network and, more particularly, to optical 25 switches and cross-connects which are required to be equipped with power equalization functionality for controlling the power of individual carriers in a WDM signal. BACKGROUND OF THE INVENTION The principle of wavelength division multiplexing consists of transporting, on a single optical waveguide such as a fiber, a plurality of independent data signals which respectively modulate a plurality of optical carriers occupying distinct optical wavelengths. This allows for significant savings when it is desired to increase the capacity of a network that already has optical fiber in place but where the fiber was previously used for transporting only a single optical carrier occupying a single optical wavelength. Since an optical carrier is implicitly associated with an optical wavelength, the expressions “optical carrier” and “optical wavelength” will hereinafter be used interchangeably. In a wavelength division multiplexed (WDM) network, each optical carrier is associated with its own source and destination nodes. Where multiple optical carriers have intersecting routes, these multiple optical carriers will occupy different wavelengths of light on the same fiber. When this type of multi-carrier signal travels along a long route, amplifiers will be required at every 80 kilometers or so in order to boost the signal's optical power. On even longer routes, a multi-carrier optical signal may not just suffer severe attenuation but it may also become distorted due to effects such as chromatic dispersion, polarization mode dispersion, signal-to-noise ratio degradation resulting from noise contributions of multiple cascaded amplifiers, and non-linearities in the optical transmission medium or in the optical components traversed along the way. Distortion of this nature is sometimes counteracted by inserting equipment in the optical path for providing dispersion compensation or banded gain equalization. In severe cases of distortion, an array of regenerators may need to be added. In its most basic form, a regenerator array detects the data on each incoming carrier and uses the detected digital data to re-modulate a fresh (usually re-shaped and re-synchronized) optical signal on the appropriate optical wavelength. Thus, a regenerator array requires, for each wavelength it is required to regenerate, an optical receiver, electronic re-shaping and re-timing circuitry and an optical source. For a dense wavelength division multiplexing (DWDM) system with typically 32 to 160 wavelengths per fiber, this leads to a very complex regenerator array. In order to allow the flexible interconnection of optical carriers, an optical network must be equipped with a mechanism for providing switching functionality at the optical carrier level. Traditionally, an optical interconnect mechanism is implemented either as an optical patch panel or as an electrical switch (or cross-connect) with optical-to-electrical converters at its input and electrical-to-optical converters at its output. A cross-connect differs from an switch in that for the case of a cross-connect, the connection map is usually provisioned from a central network management tool, either automatically or manually, whereas for the case of an optical switch, the connection map can be controlled in real time and may even be controlled by the traffic content through the switch, in which case the switch is said to be self-routing. In the interest of simplicity, and because a switch inherently encompasses a cross-connect as well as a switch in the strict sense of the term, references made to a switch in the remainder of the specification should be understood to mean a cross-connect or a switch, depending on the circumstances. While an electrical switch provides adequate switching functionality for a low density of wavelength division multiplexing, i.e., to a small number of optical carriers per fiber, those skilled in the art will appreciate that as the density of a WDM optical network grows, it becomes prohibitively expensive (both pecuniarily and from the point of view of power consumption) to equip an electrical switch with sufficient optical-to-electrical and electrical-to-optical conversion resources to handle multiple incoming dense WDM signals arriving on their respective optical fibers. To this end, the art has seen the development of the “photonic” switch (or cross-connect), which is the counterpart to the electrical switch (or cross-connect). In a photonic switch, switching is performed almost purely in the optical domain with only minimal recourse to optical-to-electrical or electrical-to-optical conversion. This advantageously results in significant reductions to the cost and complexity of the switching equipment. A photonic switch can take on many generic forms, one of which is shown in FIG. 1 and more fully described in above-referenced co-pending U.S. patent application Ser. No. 09/511,065. The photonic switch 100 typically comprises N individual M-output wavelength division demultiplexing (WDD) devices 110 A - 110 N , where each WDD device is associated with a respective one of N input fibers 120 connected to a respective set of N amplifiers 125 . The photonic switch 100 also comprises N individual M-input wavelength division multiplexing (WDM) devices 130 A - 130 N , one WDM device for each of N output optical fibers 140 connected to a respective set of N amplifiers 145 . The photonic switch 100 also comprises a photonic switch core 150 connected between the WDD devices 110 A - 110 N and the WDM devices 130 A - 130 N and a switch controller 160 connected to the photonic switch core 150 . On the input side of the photonic switch 100 , each of the N WDD devices 110 A - 110 N accepts a respective input WDM signal on a respective one of the input optical fibers 120 . Each of the N WDD devices 110 A - 110 N then separates the respective input WDM signal on a per-wavelength basis into a plurality (M) of input individual optical carrier signals which are provided to an input side of the photonic switch core 150 along a respective plurality (M) of demuxed input optical paths 170 , which may consist of optical fibers, silica waveguides or other optical transmission media. The photonic switch core 150 switches the input individual optical carrier signals, thereby to produce a plurality of switched individual optical carrier signals which are carried out of the photonic switch core 150 by a plurality of demuxed switched optical paths 180 . The switch controller 160 generates a connection map under external or locally generated stimulus, which connection map is provided to the photonic switch core 150 and defines the desired map of the optical channels from the input side to the output side of the photonic switch core 150 . External stimulus may be provided via a control link 165 . At the output of the photonic switch core 150 , each of the WDM devices 130 A - 130 N receives a respective set of demuxed switched optical paths 180 and combines the switched individual optical carrier signals thereon into a single respective WDM signal that exits the photonic switch 100 along a respective one of the output optical fibers 140 . In the illustrated embodiment, the photonic switch core 150 comprises a wavelength converting switch 190 and M optical switch matrices 150 A - 150 M , one for each of the M optical wavelengths in the system. Each optical switch matrix has a set number of input ports and output ports and can be a Micro-Electro-Mechanical System (MEMS) device as described in “Free-Space Micromachined Optical-Switching Technologies and Architectures” by Lih Y. Lin of AT&T Labs-Research during OFC99 Session W14-1 on Feb. 24, 1999. This article is incorporated by reference herein. Such a MEMS device comprises a set of mirrors that are arranged in geometrical relationship with the input and output ports such that incoming light from any input port can be diverted to any output port by erecting an appropriate one of the mirrors under control of the switch controller 160 . In FIG. 1 , each of the optical switch matrices 150 A - 150 M has a total of K+N input ports and K+N output ports where, it is recalled, N is the number of WDD devices 110 A - 110 N and WDM devices 130 A - 130 N . For each of the optical switch matrices 150 A - 150 M , each of the N input ports will be connected to the like-wavelength output port of a respective one of the WDD devices 110 A - 110 N , while each of the N output ports will be connected to the like-wavelength input port of a respective one of the WDM devices 130 A - 130 N . This permits optical signals of a given wavelength entering a switch matrix 150 A - 150 M to be connected to the appropriate port of any of the exiting WDM devices 130 A - 130 N . It is thus noted that each of the optical switch matrices 150 A - 150 M has K more input ports and K more output ports than are required to switch the N corresponding input individual optical carrier signals (one of which arrives from each of the N WDD devices 110 A - 110 N ). These additional ports are connected to the wavelength converting switch 190 , with two important consequences. Firstly, optical carrier signals arriving on demuxed input optical paths 170 can be redirected towards the wavelength converting switch 190 . Secondly, optical carrier signals arriving from the wavelength converting switch 190 can be output onto one of the demuxed switched optical paths 180 . The net result is that a signal on an individual optical carrier is allowed to change wavelengths on its way through the photonic switch 100 by a process which involves optical reception, opto-electronic conversion, electrical switching of the converted electrical signal to an optical source at a desired wavelength and modulation of that source's optical output. The wavelength conversion process is particularly useful when an input wavelength is already in use along the fiber path leading to a destination WDM device. It should further be noted that the wavelength converting switch 190 also accepts a plurality of “add carriers” on a plurality (R) of add paths 192 and outputs a plurality of “drop carriers” on a plurality (R) of drop paths 194 . Thus, it is seen that the wavelength converting switch 190 has a total of ((K×M)+R) inputs and a like number of outputs. Structurally, the wavelength converting switch 190 comprises a set of ((K×M)+R) electrical-to-optical converters, an electrical switch and a set of ((K×N)+R) optical-to-electrical converters that collectively function as a miniature version of an electrical switch for optical signals. The term “wavelength converting switch” will hereinafter be used throughout the following, with the understanding that such a switch may have either purely wavelength conversion capabilities or both wavelength conversion and add/drop capabilities. In operation, the photonic switch 100 of FIG. 1 provides purely optical switching at the optical switch matrices 150 A - 150 M and wavelength conversion (most commonly through the use of electrical switching) at the wavelength converting switch 190 . Control of which input individual optical carrier signals are redirected into the wavelength converting switch 190 is provided by the switch controller 160 . The switch controller 160 also provides control of the switching executed inside the wavelength converting switch 190 . With the assistance of network-level control of the wavelengths used by the various sources in the network, it is usually possible to ensure that most wavelengths can transit directly across most nodes in the network without wavelength conversion, hence ensuring that the majority of optical carriers will be sent along the desired output optical fiber 140 directly by the optical switch matrices 150 A - 150 M without involving the wavelength converting switch 190 . As a result, it is usually possible to achieve a minimal blocking probability at the photonic switch 100 by selecting a relatively small value for K, i.e., by keeping most of the switching entirely in the optical domain. The photonic switch described in part herein above and described in more detail in co-pending U.S. patent application Ser. No. 09/511,065 is an example of how developments in the field of optical switching are often stimulated by the need to accommodate the ever increasing optical wavelength density of WDM networks in general and WDM signals in particular. In addition, the increase in density has driven up the cost associated with providing optical signal regeneration. This is largely due to the higher number of optical sources and receivers which must be provided at a regenerator site in order to handle the increased number of optical carriers per fiber, since each optical carrier has to be regenerated separately and independently. Consequently, those skilled in the art have begun to concentrate on lowering the cost of regeneration by trying to expand the reach between optical regeneration points in a dense WDM network. The reach between optical regeneration points is limited by the build-up of degradation suffered by the optical carriers in the WDM signal which cannot be removed (and may actually be introduced) by current optical amplifiers. Specifically, the maximum reach attainable between first and second regeneration points is limited by factors such as: launch power and pulse shape at the first regeneration point; receiver sensitivity at the second regeneration point; build-up of uncompensated chromatic dispersion and polarization mode dispersion along the route; accumulation of noise arising from cascades of intervening amplifiers; excessive flat gain or loss of intervening amplifiers, WDM/WDD elements, connectors, splices and fibers; wavelength-dependent gain or loss through intervening amplifiers, WDM/WDD elements, connectors, splices and fibers; and cross-modulation and inter-modulation effects. Many of the above factors contribute to producing a non-flat optical power spectrum of the WDM signal, i.e., the individual optical carriers will experience different amounts of gain and loss as they propagate. The resulting WDM signal with a non-flat optical power spectrum will reduce the maximum reach because optical carriers having higher power may saturate the intervening optical amplifiers, while optical carriers having lower power may not be detected with sufficient accuracy by a far-end regenerator. Consequently, the power differential between high power carriers and low power carriers has to be minimize in order to maximize the reach between regenerators. In attempting to solve this problem, it has been realized that for a conventional point-to-point WDM system, variations in the optical power of the component carriers of a WDM signal are often correlated between one optical carrier and its neighbours in the optical spectrum, due to having undergone a common, wavelength-dependent amplitude distortion process. Conventional spectrum flattening techniques take advantage of this realization to provide “band equalization” of the power spectrum at an intermediate component between two regenerators. This type of equalization technique is now described with reference to FIG. 2 . Specifically, a band WDD device 4 may be used to separate an original WDM signal arriving on an input optical fiber 2 into a plurality of separate optical paths each consisting of a number of signals occupying mutually exclusive optical frequency bands. For simplicity of illustration, there are three groups of signals occupying three bands denoted A, B, C, but there may be five bands in a typical band equalization scenario. The three separated groups of signals are still WDM signals in their own right but have fewer carriers than the original WDM signal. Each of the three signals in bands A, B, C passes through a respective one of a plurality of variable optical intensity controllers (VOICs) 6 , 8 , 10 . Each of the VOICs 6 , 8 , 10 could be an amplifier or an attenuator having a response which is controllable within the band of interest but is irrelevant elsewhere. The outputs of the three VOICs 6 , 8 , 10 are then recombined by a band WDM device 12 into a recombined WDM signal provided on an output optical fiber 14 . In FIG. 2 , the optical power spectrum of the original WDM signal on the input optical fiber 2 is shown at 16 and, in this example, is seen to comprise a total of fifteen optical carriers, five in each of the three broad optical frequency bands A, B, C. The correlation among the power levels of neighbouring carriers in the input optical power spectrum 16 is apparent from the diagram. In addition, it is seen that the overall peak-to-peak power level variation (shown at 18 ) of the input optical power spectrum 16 is significant. However, because of the correlation among the power levels of neighbouring carriers, it is possible to identify an average power level 19 A , 19 B , 19 C in each respective band such that the peak-to-peak power level variation with respect to that average power level in that band is reduced as compared to the overall peak-to-peak power level variation 18 . In order to achieve band equalization, the gain (or attenuation) to be applied by each of the VOICs 6 , 8 and 10 is set to a value which complements the estimated average power level in the corresponding band in order to bring the average power level to a target level. Since the band equalization is usually a static technique, average power level estimates can be obtained at installation time. In the case of FIG. 2 , comparing the average power levels 19 A, 19 B and 19 C in bands A, B and C (which can be estimated at installation time), it is seen that VOIC 6 should be accorded a moderate gain, VOIC 8 should be accorded a high gain and VOIC 10 should be accorded a low gain. After applying band equalization in the manner of FIG. 2 , the optical power spectrum (shown at 20 ) of the recombined WDM signal provided on the output optical fiber 14 is seen to have a significantly lower overall peak-to-peak power level variation (shown at 22 ) when compared to the overall peak-to-peak variation 18 in the original WDM signal. However, it will be apparent that the band equalization approach does not completely remove peak-to-peak variations in the optical power spectrum of the original WDM signal. Rather, it provides a mechanism for reducing the level of variation and results in this level of reduction being traded off against implementational complexity by exploiting the correlation existing between adjacent carriers. Therefore, as seen in FIG. 2 , the resultant WDM signal travelling on the output optical fiber 14 still contains wavelength-dependent variations in its optical power spectrum 20 . Furthermore, the band equalization technique illustrated in FIG. 2 does not account for wavelength-dependent power level variations which may have been introduced by the band demultiplexer 4 and the band multiplexer 12 . Although not explicitly shown in FIG. 2 , the optical power spectrum 20 of the output WDM signal could conceivably contain even more significant variations due to the compounded effects of the band demultiplexer 4 and the band multiplexer 12 . A further cause of variance in the optical power spectrum of a WDM signal is the action of a photonic switch such as that shown in FIG. 1 . Specifically, because the connection map of the photonic switch is arbitrary, being driven by traffic connectivity considerations rather than optical link considerations. Thus, a particular output WDM signal emerging from the photonic switch will contain optical carriers that will likely have traveled along entirely different paths through the network. Each of these paths is associated with its own loss characteristics and therefore the various individual optical carrier optical signals that make up a WDM signal at the output of the photonic switch will have respective optical power level which are uncorrelated with one another. The situation is illustrated in FIG. 3 , where a 3×3 photonic switch 300 is connected to three input optical fibers 40 , 42 , 44 and three output optical fibers 60 , 62 , 64 . The input optical power spectrum of the WDM signal on each of the input optical fibers 40 , 42 , 44 is shown at 50 , 52 , 54 , respectively. Each of these three input optical power spectra 50 , 52 , 54 occupies the same optical frequency range but has a distinct shape. In particular, the shape of each of the optical power spectra 50 , 52 , 54 displays a certain degree of correlation among the power levels of neighbouring carriers. For example, spectrum 50 has a monotonically decreasing shape, spectrum 52 has a bell shape and spectrum 54 is composed of relatively constant power levels. Since any arbitrary connection map may be provided by the photonic switch 300 at a given instant in time, the correlations existing among the carrier power levels on a the input optical fibers 40 , 42 , 44 may not carry through to the output optical fibers 60 , 62 , 64 . Hence, the output optical spectra (shown at 70 , 72 , 74 ) will exhibit a poor correlation among individual carriers and will appear “randomized”. This effect may be compounded by differing losses experienced by the various signals as they transit the switch node components. Clearly, as a result of this lack of correlation among individual carriers, a band equalization technique such as that previously described with reference to FIG. 2 would be of little use if applied at the output or even at the input of the photonic switch 300 . Those skilled in the art will also appreciate that in addition to being affected by spectral variations arising from the arbitrary connection map applied by a photonic switch, the optical power spectrum of an output WDM signal may be further distorted by wavelength-dependent losses induced by a WDM device positioned at the output of the switch and, to a certain extent, by path-dependent losses through the photonic switch core. Hence, it will be appreciated that the optical power spectrum of the WDM signals exiting a photonic switch can be severely distorted and, worse still, the distortion has no predictable spectral shape. Moreover, the optical power spectrum of the WDM signals can change dramatically and suddenly with each change in the connection map. Clearly, such wavelength-dependent distortion presents a serious limitation on the reach between the photonic switch and the next regeneration point in the network and therefore it would be a tremendous advantage to provide spectral flattening at the photonic switch, without adding significant complexity to the design of the photonic switch itself. SUMMARY OF THE INVENTION The present invention is directed to providing each signal at the output of a photonic switch with a controllable (e.g., flat) optical power spectrum, while only slightly increasing the complexity of the switch design. The equalization system, or “equalizer”, of the present invention controllably adjusts the optical power of each individual optical signal passing through the photonic switch by placing a plurality of variable optical intensity controllers (VOICs) in each optical path prior to wavelength recombination. The VOICs can be variable optical amplifiers or variable optical attenuators. The VOICs are controlled by a controller which derives power estimates from individual optical carrier signals extracted from the WDM signals at the output of the photonic switch. In this way, many advantages are achieved. Firstly, individual and independent control of the power on each optical channel is provided. Secondly, wavelength-dependent losses introduced by all the devices in the switch including the WDM devices at the output of the switch are accounted for. Thirdly, tapping the output WDM signals requires only one optical coupler for each output optical fiber, reducing the complexity of the equalization system. Fourthly, tapping the output WDM signals at the output of the switch has no effect on the system's noise floor. In some embodiments of the invention, coarse equalization is provided for each multiplexed optical signal either at the input to the switch or at the output of the switch. This permits a reduction in the dynamic range over which the VOICs are required to operate, which advantageously allows the use of cheaper components. In other embodiments of the invention, the controller in the equalizer will reduce the intensity of the individual optical signals that are effected by a forthcoming change in the connection map of the switch. The intensity is then gradually increased to a reference value once the new connection map is applied. This mapping procedure prevents existing carriers from being effected by sudden power level changes to other carriers sharing the same output optical fiber and optical amplifier chain. In still other embodiments, the invention provides a calibration functionality. This can be achieved by evaluating the relative loss of each possible fiber/wavelength combination through the front end of the equalizer. In this way, spectral variations due to tolerances in the equalizer can be significantly reduced. In a broad sense, the invention may be summarized as an optical intensity control system for use with an optical switch providing individual signal paths between a plurality of input ports and a plurality of output ports. The switch typically has a plurality of wavelength division multiplexers for combining sets of individual switched optical signals into multiplexed switched optical signals. The intensity control system of the invention is equipped with a plurality of optical splitters, each being connectable to an output of a respective one of the wavelength division multiplexers and a plurality of variable optical intensity controllers (VOICs) for insertion into respective ones of the individual signal paths and for individually controlling the intensity of optical signals present in the respective ones of the individual signal paths in accordance with respective intensity control signals. The intensity control system of the invention is further equipped with an equalizer connected to the splitters and to the VOICs, for producing an estimate of the optical power of each individual switched optical signal and generating the intensity control signals as a function of the estimates of optical power. This allows the optical powers of each of the carriers to be changed, resulting in a substantially equal power in each optical carrier. The equalizer may have a front end circuit with a plurality of inputs for receiving the multiplexed switched optical signals, where the front end circuit is adapted to controllably isolate individual switched optical signals from the multiplexed switched optical signals. The equalizer also has an optical receiver unit connected to the front end circuit, for converting any isolated individual switched optical signals to electrical signals. The equalizer is further equipped with a power estimation unit connected to the optical receiver unit, for time-averaging the electrical signals, thereby to obtain respective estimates of optical power. Finally, the equalizer has a processor connected to the power estimation unit and to the front end circuit, where the processor is adapted to cause the front end circuit to isolate selected individual switched optical signals and also to generate the intensity control signals from the estimates of optical power. In some embodiments, front end circuit has wavelength-tunable optical bandpass filters connected to outputs of the optical splitters. The processor is then adapted to selectably tune the filters in order to cause individual switched optical signals to be selected on the basis of fiber origin and individual wavelength. In other embodiments, the front end circuit is equipped with an optical switch matrix having a plurality of inputs respectively connected to the plurality of splitters and having a plurality of controllably erectable mirrors, as well as a wavelength division demultiplexer connected to an output of the switch matrix. In this case, the processor is adapted to selectably raise one mirror at a time on the optical switch matrix in order to cause selected individual switched optical signals to be isolated. The front end circuit may alternatively comprise a first optical switch matrix having a plurality of inputs respectively connected to the plurality of splitters and having a plurality of controllably erectable mirrors, as well as a wavelength division demultiplexer connected to an output of the first switch matrix and at least one second optical switch matrix, where each second optical switch matrix has a plurality of inputs connected to the wavelength division demultiplexer and having a plurality of controllably erectable mirrors. The processor would then be adapted to selectably raise one mirror at a time on the first optical switch matrix and to raise one mirror at a time on the at least one second optical switch matrix in order to cause selected individual switched optical signals to be isolated. In still other cases, the front end circuit has (1) a first optical switch matrix having a plurality of inputs respectively connected to the plurality of splitters and having a plurality of controllably erectable mirrors, (2) a wavelength division demultiplexer connected to an output of the first switch matrix, (3) at least one second optical switch matrix, each the second optical switch matrix having a plurality of inputs connected to the wavelength division demultiplexer and having a plurality of controllably erectable mirrors and (4) a coupler connected to an output of each second optical switch matrix. The invention may also be broadly summarized as a method of generating control signals for adjusting the intensity of single-carrier optical signals travelling through an optical switch, wherein groups of individual switched optical signals are recombined into multiplexed switched optical signals at an output end of the switch. The method includes the steps of: (a) controllably isolating individual switched optical signals from the multiplexed switched optical signals; (b) estimating the power of the individual switched optical signals isolated at step (a); and (c) generating the control signals as a function of the power estimates obtained at step (b) and a reference value. The invention can also be broadly summarized as a switch for optical signals, which has wavelength division demultiplexers, wavelength division multiplexers, optical splitters connected to the multiplexer output port of a respective one of the wavelength division multiplexers, a switching core connected between the wavelength division demultiplexers and the wavelength division multiplexers, a plurality of variable optical intensity controllers (VOICs) positioned in respective ones of the optical paths, and an equalizer as described above, connected to the couplers and to the VOICs. The switching core may comprise a plurality of core optical switching matrices, each core optical switch matrix being associated with a distinct optical wavelength. The switching core may further comprise a wavelength-converting inter-matrix switch connected to the core optical switching matrices, for receiving optical signals from the core optical switching matrices, converting each received optical signal to electrical form and transmitting each converted signal at a changed wavelength to the core optical switch matrix associated with the changed wavelength. If optical switch matrices are used in the equalizer, at least one such optical switch matrix can be in a stacked relationship with respect to one or more core optical switch matrices to improve compactness. The invention may also be summarized broadly as a method of calibrating power estimates received at a processor connected to an optical carrier selection circuit in an intensity control loop. The method includes the steps of: obtaining a reference estimate of the optical power of a reference light source without the effect of the optical carrier selection circuit; controlling the optical carrier selection circuit in order to obtain an estimate of the optical power of the reference light source for each of a plurality of possible optical paths through the optical carrier selection circuit; generating a calibration factor for each path by evaluating a function of the difference between the corresponding received power estimate and the reference estimate; and adjusting subsequent power estimates for each path by the corresponding calibration factor. BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects and features of the present invention will now become apparent to those of ordinary skill in the art upon review of the accompanying description of specific embodiments of the invention in conjunction with the following drawings, in which: FIG. 1 , already described, shows a photonic switch in block diagram form; FIG. 2 , already described, shows in block diagram form an implementation of a band equalization technique; FIG. 3 , already described, shows the effects of a photonic switch on the power spectrum of a WDM signal at the output of the photonic switch; FIG. 4 shows in block diagram form part of a photonic switch in accordance with an embodiment of the present invention; FIGS. 5 through 9 show, in block diagram form, specific embodiments of an equalizer forming part of the photonic switch of FIG. 4 ; FIG. 10 shows a message flow diagram between controllers inside and outside the equalizer under transient conditions; FIG. 11 is a table illustrating a comparative summary of the component requirements of the embodiments of FIGS. 5 through 9 ; FIG. 12 is a block diagram of an embodiment of the photonic switch of the invention which uses coarse intensity control at the input to the switch; FIG. 12A shows a variation of the embodiment of FIG. 12 ; FIG. 13 is block diagram of another embodiment of the photonic switch of the invention which uses coarse intensity control at the input to the switch; FIG. 14 is a block diagram of an embodiment of the photonic switch of the invention which uses coarse intensity control at the output of the switch; FIG. 15 is a block diagram of an embodiment of the photonic switch of the invention with calibration functionality; and FIG. 16 shows the application of calibration functionality to the embodiment of FIG. 12A . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 4 , there is shown a photonic switch 400 according to an embodiment of the present invention. The photonic switch 400 resembles the photonic switch 100 of FIG. 1 in that it retains the basic structure including the WDD devices 110 A - 110 N , the WDM devices 130 A - 130 N and the photonic switch core 150 . The photonic switch 400 of the invention additionally comprises a plurality (M×N) of variable optical intensity controllers (VOICs) 410 respectively positioned in each of the demuxed switched optical paths 180 . Thus, each of the VOICs 410 is associated with a respective switched individual optical carrier signal that emerges from the photonic switch core 150 along a respective one of the demuxed switched optical paths 180 . The VOICs 410 are used for providing intensity control in the form of either attenuation or amplification. Thus, each of the VOICs 410 can either be a variable optical attenuator or a variable optical amplifier, depending on the operational requirements of the invention. The range of intensity control (i.e., attenuation or gain) required of an individual VOIC is typically expected to be on the order of 8 decibels (dB) or less, although it is within the scope of the invention to provide a greater or smaller dynamic range of attenuation or gain. It is convenient to view the VOICs 410 as forming an array of size M×N where, it is recalled, N is the number of WDM devices 130 A - 130 N and M is the number of wavelengths handled by each WDM device (which is also the number of optical switch matrices 150 A - 150 M in the photonic switch core 150 ). Typical values for M are 32 and above, while typical values for N are 4 and above. However, it should be understood that the invention is not subject to any limitation on M or N. Each of the VOICs 410 has a control port for receiving a respective intensity control signal along a respective one of a plurality of intensity control lines generally indicated by the reference numeral 415 . Each such intensity control line carries an intensity control signal indicative of a desired amount of attenuation or gain to be applied by the respective VOIC. The intensity control line leading to the VOIC corresponding to the J th optical switch matrix 150 J and the K th WDM device 130 K can be denoted 415 J,K , where Jε{A, B, . . . , M} and Kε{A, B, . . . , N}. With continued reference to FIG. 4 , the photonic switch 400 of the invention further comprises a plurality (N) of directional couplers 420 (also referred to as optical splitters), each of which intercepts the optical path of a respective one of the N output optical fibers 140 . It is noted that the number of couplers 420 is equal to the number of output optical fibers 140 , which is M times less than the total number of demuxed switched optical paths 180 . It should be understood that the couplers (splitters) 420 could be placed after the amplifiers 145 (as shown) or in front of the amplifiers 145 , depending on the operational requirements of the invention. For instance, if it is important to allow openness so that 3 rd party amplifiers 145 can be used, then it is desirable to place the couplers 420 in front of the amplifiers 145 . However, such a configuration would not permit the power spectrum equalizer 500 to compensate for spectral gain variations introduced by the amplifiers 145 . Therefore, to compensate for such variations, it would be advantageous to place the couplers 420 after the amplifiers 145 . Each of the N couplers 420 can be a standard component which is designed to tap a small, known amount of optical power from the respective output optical fiber 140 . A suitable amount of optical power tapped in this manner will be 10 dB to 13 dB below the optical power level on the respective output optical fiber 140 . This lowers the optical power level of the ongoing signal by only 0.22 dB to 0.46 dB, which loss can then be compensated for by increasing the gain of the respective amplifier (when the couplers 420 are placed in front of the amplifiers 145 ) or by increasing the gain (decreasing the attenuation) of the VOICs 410 associated with that amplifier. The photonic switch 400 of the present invention further comprises a power spectrum equalization control system (hereinafter simply referred to as an “equalizer”) 500 which is placed between the couplers 420 and the VOICs 410 and which communicates with a switch controller 160 ′ via a control line 440 . The switch controller 160 ′ is similar to the switch controller 160 in FIG. 1 with additional special operational features that will be described later on. As with the switch controller 160 of FIG. 1 , the switch controller 160 ′ of FIG. 4 communicates with the outside world by a control link 165 . The equalizer 500 is connected to each of the N couplers 420 by a respective one of a plurality of optical paths 425 A - 425 N , where optical path 425 A carries a tapped WDM optical signal from WDM device 130 A , optical path 425 B carries a tapped WDM optical signal from WDM device 130 B , and so on. The equalizer 500 is further connected to the control port of each of the M×N VOICs 410 by a respective one of the plurality of intensity control lines 415 . The equalizer 500 may have a variety of internal configurations, some of which will be described in further detail later on. A feature common to each structure is the provision of suitable circuitry, software and/or control logic for: receiving tapped optical signals from the couplers 420 along the optical paths 425 A - 425 N ; processing the tapped optical signals according to an algorithm (still to be described); and generating intensity control signals to be supplied to the M×N individual VOICs 410 via the M×N intensity control lines 415 . Thus, the equalizer 500 controls the amount of gain or attenuation to be applied by each of the VOICs 410 . This is done with the aim of flattening the optical power spectrum of each output WDM signal. Specific embodiments of the equalizer 500 are now described with reference to FIGS. 5 , 6 , 7 , 8 and 9 . In FIG. 5 , the equalizer 500 is seen to comprise N individual M-output WDD devices 510 A - 510 N , each of which is connected to a respective one of the couplers 420 via a respective one of the optical paths 425 A - 425 N . Each of the WDD devices 510 A - 510 N is designed to separate the received, coupled version of the respective output WDM signal into its M individual optical carrier components. Therefore, the M signals at the output of each of the WDD devices 510 A - 510 N correspond to the M switched individual optical carrier signals as combined by the respective one of the WDM devices 130 A - 130 N . Each of the WDD devices 510 A - 510 N is connected to a respective set of M optical receivers. For notational convenience, the particular optical receiver associated with the switched individual optical carrier signal carried along one of the demuxed switched optical paths 180 from the J th optical switch matrix 150 J to the K th WDM device 130 K can be denoted 520 J,K . Thus, in FIG. 5 , WDD device 510 A is connected to optical receivers 520 A,A , 520 B,A , . . . 520 M,A , WDD device 510 B is connected to optical receivers 520 A,B , 520 B,B , . . . 520 M,B , etc., and WDD device 510 N is connected to optical receivers 520 A,N , 520 B,N , . . . 520 M,N . The optical receivers (collectively denoted by 520 ) each comprise circuitry such as a photodiode and a trans-impedance amplifier for converting into electrical form an optical signal present at its input. In the embodiment of FIG. 5 , the signal received at the input to a given optical receiver is always at the same wavelength, and therefore each of the optical receivers 520 can be a narrow-optical-bandwidth component tuned to the appropriate optical wavelength. The M×N optical receivers 520 are respectively connected to a plurality (M×N) of power estimation modules. The individual power estimation module connected to optical receiver 520 J,K for a particular value of J and K can be denoted by 530 J,K . Thus, the power estimation module denoted by 530 A,A is connected to optical receiver 520 A,A , and so on. Each of the power estimation modules (collectively denoted by 530 ) comprises circuitry, firmware or control logic for estimating the power of the optical signal from which the electrical signal received from the respective one of the optical receivers 520 was derived. Since optical power is directly proportional to optical intensity, suitable power estimation circuitry could include circuitry for measuring the average voltage of the received electrical signal, from which the optical power can be determined. Of course, those skilled in the art will be familiar with other methods of power estimation. Furthermore, sampling and digitizing operations can be performed either prior or subsequent to power estimation. It will also be appreciated that as long as the digital signal on each optical wavelength has a duty cycle of approximately 50% (i.e., has an approximately equal number of zeroes and ones over a pre-determined integration interval), the receivers 520 and power estimation modules 530 can be low-speed components for measuring average power over such an integration interval. With continued reference to FIG. 5 , the power estimate produced by each of the power estimation modules 530 is provided to a respective input of a controller 550 . In the embodiment of FIG. 5 , the controller 550 is equipped with a M×N-input multiplexer 552 which is connected to a processor 554 . The processor 554 selectively reads the power estimates through control of the multiplexer 552 via a control line. The processor 554 comprises suitable circuitry, software and/or control logic for processing the power estimates received from the power estimation modules 530 and generating intensity control signals for transmittal to the VOICs 410 along the intensity control lines 415 . Operation of the processor 554 in accordance with an equalization algorithm will be described in further detail later on. As shown in FIG. 5 , the processor 554 may be connected to the VOICs by a plurality (M×N) of latches 556 and an intervening demultiplexer 558 . Thus, the processor 554 may provide the intensity control signals one at a time to the demultiplexer 558 along a single signal line. Under control of the processor 554 , the demultiplexer 558 then sends the received intensity control signal to the appropriate one of the latches 556 , where the present value of the intensity control signal is held until further notice. Another specific embodiment of the equalizer 500 is shown in FIG. 6 . In this case, the equalizer 500 comprises a plurality of wavelength-tunable optical bandpass filters 610 A - 610 N , each of which is connected to a respective one of the couplers 420 via a respective one of the optical paths 425 A - 425 N . A wavelength-tunable optical bandpass filter is a known component which passes a selectable optical frequency range of an input signal as a function of a control voltage or current supplied to the filter. Thus the need for WDD devices at the input to the equalizer 500 can be avoided, while reducing the total required number of optical receivers and power estimation modules. Specifically, the output of each of the wavelength-tunable optical bandpass filters 610 A - 610 N is connected to a respective one of a plurality of optical receivers 620 A - 620 N , each of which is similar to one of the optical receivers 520 previously described with reference to FIG. 5 . However, because the signal input to any one of the N optical receivers 620 A - 620 N may occupy any one of the M possible wavelengths in the system, the optical receivers 620 A - 620 N must each be operable over a wider optical bandwidth, typically the entire WDM spectrum. Each of the optical receivers 620 A - 620 N has an output which is connected to a respective one of a plurality of power estimation modules 530 A - 530 N , each of which is identical to any of the power estimation modules suitable for use in the equalizer of FIG. 5 . The power estimation modules 530 A - 530 N are connected to respective inputs of a controller 650 . In the embodiment of FIG. 6 , the controller 650 is equipped with an N-input multiplexer 652 which is connected to a processor 654 . The processor 654 selectively reads the power estimates through control of the multiplexer 652 via a control line. The processor 654 comprises suitable circuitry, software and/or control logic for processing the power estimates received from the power estimation modules 630 and generating intensity control signals for transmittal to the VOICs 410 along the intensity control lines 415 . In addition, the controller 650 comprises a filter driver 656 for varying, under control of the processor 654 , the pass band of the wavelength-tunable optical bandpass filters 610 A - 610 N via a respective plurality of control lines 615 A - 615 N . Operation of the processor 654 in accordance with an equalization algorithm will be described in further detail later on. The processor 654 may be connected to the VOICs by a plurality (M×N) of latches 556 and an intervening demultiplexer 556 . Thus, the processor 654 provides the intensity control signals one at a time to the demultiplexer. 558 along a single signal line. Under control of the processor 654 , the demultiplexer 558 then sends the received intensity control signal to the appropriate one of the latches 556 , where the present value of the intensity control signal is held until further notice. Another specific embodiment of the equalizer 500 is shown in FIG. 7 , wherein the optical paths 425 A - 425 N lead to respective inputs of an N-input optical switch matrix 710 (e.g., a MEMS based optical switch matrix as described in the previously referenced article by Lih Y. Lin of AT&T Labs-Research) which can be identical to any one of the switch matrices 150 A - 150 M in FIG. 4 . In this case, only one of the output ports of the optical switch matrix 710 is used and this particular output port is connected to an M-output WDD device 510 . However, it is possible to decrease response and scanning times by using more than one output of the optical switch matrix 710 , with each such output being connected to its own WDD device. Within the optical switch matrix 710 there is provided an arrangement of N controllably erectable mirrors 712 A - 712 N . The position of each mirror is either flat (in the plane of the optical switch matrix 710 ) or upright (perpendicular to the plane of the optical switch matrix 710 ), depending on the value of a control signal 714 . When a particular one of the mirrors 712 A - 712 N , say the p th mirror 712 p , is selected to be upright, then light arriving along the corresponding optical path 425 p from the corresponding one of the couplers 420 will be directed to the output of the optical switch matrix 710 and into the WDD device 510 . The WDD device 510 is identical to the WDD devices 510 A - 510 N of FIG. 5 and thus is designed to separate the received optical signal (arriving from the optical switch matrix 710 ) into its M component wavelengths. The signals output by the WDD device 510 arrive at respective ones of a plurality of optical receivers 520 A - 520 M . Since each of the optical receivers 520 A - 520 M is dedicated to processing signals having a fixed wavelength, each of the optical receivers 520 A - 520 M can have a narrower optical bandwidth than the receivers 620 A - 620 N in FIG. 6 . Thus, each of the optical receivers 520 A - 520 M can be identical to any of the optical receivers suitable for use in the equalizer of FIG. 5 and is accordingly designated by the same reference character. The number of such optical receivers in the embodiment of FIG. 7 is equal to the number of wavelengths (which is M). Each of the optical receivers 520 A - 520 M is connected to a respective one of a plurality of power estimation modules 530 A - 530 M , each of which can be identical to any of the power estimation modules suitable for use in the embodiments of FIGS. 5 and 6 . The number of power estimation modules 530 in the embodiment of FIG. 7 is equal to the number of wavelengths (M). The power estimation modules 530 A - 530 M are connected to respective inputs of a controller 750 . In the embodiment of FIG. 7 , the controller 750 is equipped with an M-input multiplexer 752 which is connected to a processor 754 . The processor 754 selectively reads the power estimates through control of the multiplexer 752 via a control line. The processor 754 comprises suitable circuitry, software and/or control logic for processing the power estimates received from the power estimation modules 530 A - 530 M and generating intensity control signals for transmittal to the VOICs 410 along the intensity control lines 415 . In addition, the controller 750 comprises a switch driver 758 for raising, under control of the processor 754 , a selected one of the mirrors 712 A - 712 N in the optical switch matrix 710 . Operation of the processor 754 in accordance with an equalization algorithm will be described in further detail later on. As was described earlier with reference to FIGS. 5 and 6 , the processor 754 may be connected to a plurality (M×N) of latches 556 by a demultiplexer 558 . Thus, the processor 754 provides the intensity control signals one at a time to the demultiplexer 558 along a single signal line. Under control of the processor 754 , the demultiplexer 558 then sends the received intensity control signal to the appropriate one of the latches 556 , where the present value of the intensity control signal is held for the respective VOIC until further notice. In FIG. 8 is shown yet another embodiment of the equalizer 500 of the present invention, representing an elegant simplification in the design. In this embodiment, there is provided a first N-input optical switch matrix 710 (identical to that of FIG. 7 ) which is connected to a WDD device 510 (identical to those of FIGS. 5 and 7 ). The elevation of a particular mirror in the optical switch matrix 710 is controlled by a control signal received along a control line 714 . The output of the optical switch matrix 710 contains a multi-wavelength optical signal which is split into its M optical carrier components by the WDD device 510 . The WDD device 510 is connected to one or more additional N-input optical switch matrices 710 ′. Each of the optical switch matrices 710 ′ consists of an arrangement of controllably erectable mirrors whose position is either flat or upright as controlled by another control signal received along another control line 714 ′. Thus, only one output of each of the optical switch matrices 710 ′ is actually used. Of course, in order to use only one N-input optical switch matrix 710 ′, then N (the number of input or output optical fibers) should be greater than or equal to M (the number of wavelengths in the system). Since in many cases this condition cannot be satisfied, it becomes necessary to provide a number of optical switch matrices 710 ′ equal to ceil(M÷N), where ceil(M÷N) represents the smallest integer value not less than the quotient of M and N. The case where ceil(M÷N)=2 is shown in FIG. 8 , there being provided two optical switch matrices 710 ′ with the output of each optical switch matrix being coupled together at a coupler 810 . Alternatively, the coupler 810 can be omitted and the output of each of the switch matrices 710 ′ can be provided to a controller 850 via separate paths. In either case, by ensuring that only one of the mirrors on only one of the optical switch matrices 710 ′ is upright at any one time, the multiple optical switch matrices 710 ′ can be made to behave as a single M-input optical switch matrix. An advantage of using multiple N-input optical switch matrices 710 ′ rather than one M-input optical switch matrix is that N-input optical switch matrices 710 ′ have the exact same dimensions as the optical switch matrices 150 A - 150 M in the photonic switch core 150 and can be fully integrated therewith. Thus, the optical switch matrices 710 , 710 ′ can be stacked or aligned with respect to the optical switch matrices 150 A - 150 M in the photonic switch core 150 , thereby improving compactness of the switch as a whole. The output of the coupler 810 is connected to the optical receiver 620 which can be identical to any of the optical receivers previously described with reference to FIG. 6 , i.e., the optical receiver 620 must have a sufficiently wide optical bandwidth of operation to handle optical carrier signals occupying different wavelengths at different times. If the coupler 810 is dispensed with, then the output of each of the optical switch matrices 710 ′ could be connected to its own wide-optical-bandwidth optical receiver. The optical receiver 620 is connected to a power estimation module 530 , which can be identical to any of the power estimation modules suitable for use in the embodiments of FIGS. 5 , 6 and 7 . If the coupler 810 is omitted from the design, then the number of optical receivers and power estimation modules would equal the number of optical switch matrices 710 ′, which is equal to ceil(M÷N). The power estimation module 530 is connected to an input of a processor 854 in the controller 850 . The processor 854 comprises suitable circuitry, software and/or control logic for processing power estimates received from the power estimation module 530 and generating intensity control signals for transmittal to the VOICs 410 along the intensity control lines 415 . Moreover, the controller 850 comprises a switch driver 858 for raising, under control of the processor 854 , exactly one of the mirrors 712 A - 712 N in the optical switch matrix 710 and exactly one of the mirrors from among all those in the one or more optical switch matrices 710 ′ connected to the WDD device 510 . This allows the processor 854 to sequentially access the individual power estimates associated with various wavelength-fiber combinations. Operation of the processor 854 in accordance with an equalization algorithm will be described in further detail later on. As was described previously with reference to FIGS. 5 through 7 , the processor 854 may be connected to a plurality (M×N) of latches 556 by a demultiplexer 558 . Thus, the processor 854 provides the intensity control signals one at a time to the demultiplexer 558 along a single signal line. Under control of the processor 854 , the demultiplexer 558 then sends the received intensity control signal to the appropriate one of the latches 556 , where the present value of the intensity control signal is held until further notice. Still another embodiment of the equalizer 500 is depicted in FIG. 9 , wherein there is provided an N-input optical switch matrix 710 much like any of the previously described optical switch matrices suitable for use in the embodiments of FIGS. 7 and 8 . The selection of which of the mirrors 712 A - 712 N is to be raised is controlled via a control link 714 . An output of the optical switch matrix 710 is connected to a single wavelength-tunable optical bandpass filter 610 much like any of the filters 610 A - 610 N suitable for use with the embodiment of FIG. 6 . Again, the use of more than one output of the optical switch matrix 710 may reduce the response and scanning time associated with measuring the power of the switched individual optical carrier signals travelling through the photonic switch 400 . The output of the wavelength-tunable optical bandpass filter 610 is connected to a processor 954 within a controller 950 via a wide-optical-bandwidth optical receiver 620 and a power estimation module 530 . The processor 954 is equipped with suitable circuitry, software and/or control logic for processing power estimates received from the power estimation module 530 and generating intensity control signals for transmittal to the VOICs 410 along the intensity control lines 415 . Moreover, the controller 950 comprises a switch driver 958 for raising, under control of the processor 954 , exactly one of the mirrors 712 A - 712 N in the optical switch matrix 710 . In addition, the controller 950 comprises a filter driver 956 for varying, under control of the processor 954 , the pass band of the wavelength-tunable optical bandpass filter 610 via a control link 615 . This allows the processor 954 to sequentially access the individual power estimates associated with various wavelength-fiber combinations. Operation of the processor 954 in accordance with an equalization algorithm will be described in further detail later on. As was described previously with reference to FIGS. 5 through 8 , the processor 954 may be connected to a plurality (M×N) of latches 556 by a demultiplexer 558 . Thus, the processor 954 provides the intensity control signals one at a time to the demultiplexer 558 along a single signal line. Under control of the processor 954 , the demultiplexer 558 then sends the received intensity control signal to the appropriate one of the latches 556 , where the present value of the intensity control signal is held until further notice. FIG. 11 provides, in tabular form, a comparative summary of the various embodiments of the controller in FIGS. 5 through 9 in terms of the number of components (optical receivers, power estimation modules, optical switch matrices, WDD devices, wavelength-tunable optical bandpass filters) required in order to implement each embodiment. It is seen that the progression of embodiments from FIG. 5 through to FIG. 9 is increasingly intricate yet elegant. The utmost in simplicity and elegance is achieved in the embodiment of FIG. 9 where the equalizer 500 requires only one power estimation module 530 , one wavelength-tunable optical bandpass filter 610 , one wide-optical-bandwidth optical receiver 620 and one N-input switch matrix 710 . As has been previously described (with reference to FIG. 8 , for example), the use of N-input optical switch matrices 710 , 710 ′ permits these switch matrices to be integrated into the structure of the photonic switch core 150 . Thus, in designing a card cage for housing the optical switch matrices 150 A - 150 M forming part of the optical switch core 150 , it is within the scope of the invention to provision additional slots not only for use with spare optical switch matrix cards but also for use with the optical switch matrix cards 710 , 710 ′ needed by the equalizer (e.g., 1 spare card for the embodiments of FIGS. 7 and 9 and ceil(M÷N) spare cards for the embodiment of FIG. 8 ). Operation of the “equalization processor” is now described. The term “equalization processor” is hereinafter used to refer to any of the processors 554 , 654 , 754 , 854 , 954 previously described with reference to FIGS. 5 , 6 , 7 , 8 , 9 , respectively. In each case, the equalization processor runs an equalization algorithm for processing the power estimates received from the power estimation module(s) 530 and for interacting with the switch controller 160 ′ via the control line 440 . The equalization algorithm has two modes of operation, the first mode being a so-called “scan mode”, which is executed under steady-state connection conditions, and the second mode being a so-called “directed mode”, which is entered upon interruption of the equalization controller while it is running in scan mode. In scan mode, operation of the equalization controller basically consists of: (1) cycling through all “valid” combinations of output optical fibers and wavelengths, and reading the power estimate associated with each such valid combination; and (2) adjusting, as a function of the power estimates, the intensity control signals being fed to the VOICs. A “valid” combination referred to in (1) above means that an optically carrier modulated data signal is expected to be found on that particular wavelength and on that particular output optical fiber. Typically, at any given instant, many combinations of output optical fiber and wavelength will be valid but some will not, i.e., it is expected that one or more wavelengths on one or more output optical fibers may not contain an optical carrier modulated data signal. Whether or not a particular combination is valid depends on the connection map and thus will be known to the switch controller 160 ′. The switch controller 160 ′ can therefore make available a list of valid combinations to the equalization processor. This list is then kept up to date in a manner to be described further on when discussing the “directed mode” of operation. Having determined that a particular combination of wavelength and output optical fiber is indeed valid, the equalization processor, still in step (1) of scan mode, must read the power estimate corresponding to this combination. The manner in which this is achieved depends on the configuration of the controller as a whole. For example, let the equalization processor be required to access the power estimate associated with the J th wavelength on the K th output optical fiber. In the embodiment of FIG. 5 , the equalization processor 554 would obtain the desired power estimate by reading the output of power estimation module 530 J,K , which is uniquely associated with the desired combination of wavelength and output optical fiber. In the embodiment of FIG. 6 , the equalization processor 654 sends a message to the filter driver 656 , which then instructs the K th wavelength-tunable optical bandpass filter 610 K to pass light occupying the J th wavelength. The equalization processor 654 would then obtain the desired power estimate by reading the output of the K th power estimation module 530 K . In the embodiment of FIG. 7 , the equalization processor 754 sends a message to the switch driver 758 , which then instructs the optical switch matrix 710 to raise the K th mirror 712 K . The equalization processor 754 would then obtain the desired power estimate by reading the output of the J th power estimation module 530 J . In the embodiment of FIG. 8 (with the coupler 810 in place), the equalization processor 854 sends a message to the switch driver 858 , which then instructs the switch matrix 710 to raise only the K th mirror and also instructs the appropriate one of the optical switch matrices 710 ′ to raise only the J th mirror. The equalization processor 854 would then obtain the desired power estimate by reading the output of the power estimation module 530 . Finally, in the embodiment of FIG. 9 , the equalization processor 954 sends a first message to the switch driver 958 , which then instructs optical switch matrix 710 to raise the K th mirror 712 K . The equalization processor 954 also sends a second message to the filter driver 956 , which instructs the wavelength-tunable optical bandpass filter 610 to pass light occupying the J th wavelength. The equalization processor 954 would then obtain the desired power estimate by reading the output of the power estimation module 530 . Now having regard to step (2) above, namely the adjustment of the intensity control signals being fed to the VOICs 410 as a function of the power estimates, the scan mode of operation provides for at least two ways of performing this step. In a preferred version of step (2) in scan mode operation, the received power estimate associated with a valid combination (e.g., the J th wavelength on the K th output optical fiber) is immediately compared to a pre-determined reference value, and the resulting difference is encoded as an intensity control signal that is fed to the demultiplexer 558 . The demultiplexer 558 is then controlled to send this intensity control signal to the appropriate one of the latches 556 , which is then used to drive the appropriate VOIC via the appropriate intensity control line 415 J,K . This procedure is repeated for each valid combination of wavelength and output optical fiber. After a finite time, the output power level of each carrier on each output optical fiber will converge to the respective desired output power level. In an alternate version of step (2) in scan mode of operation, all the power estimates associated with valid wavelengths on the K th output optical fiber are read, following which a reference output power level for the carriers on the K th output optical fiber is computed. Next, the difference between the reference output power level and the power estimate associated with a particular valid wavelength (e.g., the J th wavelength) on that K th output optical fiber is fed as an intensity control signal to the demultiplexer 558 . The demultiplexer 558 is then controlled to send this intensity control signal to the appropriate one of the latches 556 , which is used to drive the appropriate VOIC via the appropriate intensity control line 415 J,K . This procedure is repeated for each output optical fiber (i.e., for each value of K). After a finite time, the output power level of each carrier on each output optical fiber (i.e., for each set of J and K corresponding to a valid combination) will have converged to the appropriate reference output power level. It will be appreciated that either version of the scan mode of operation described above provides gain flattening which advantageously compensates for unequal and uncorrelated power levels among the carriers which would otherwise have occurred due to the arbitrary connection map applied by the photonic switch core 150 under control of the switch controller 160 ′. Furthermore, it is noted that the optical power of each carrier is estimated only after the carrier has already exited the respective one of the WDM devices 130 A - 130 N , located at the output of the photonic switch 400 . Thus, the power equalization provided by the present invention is also capable of compensating for wavelength-dependent losses introduced by the WDM devices 130 A - 130 N as well as for and path-dependent losses through the photonic switch core 150 . Moreover, because only N couplers 420 are required and because each such coupler is associated with only one of the output optical fibers 140 , another advantage of the invention is that the requirements on the tolerance of the couplers 420 need not be severe. This is due to the fact that variations in the flat loss between couplers causes a constant amplitude error across all wavelengths existing on a given fiber and therefore does not affect the spectral flatness. Moreover, such errors in the flat loss can be compensated for in the line system amplifiers 145 , if the couplers 420 are placed in front of the amplifiers 145 and if the amount of compensation is within the amplifiers' dynamic range. Having described the scan mode of operation, the need for a directed mode of operation arises in the situation where the controller 160 ′ is ready to instruct the photonic switch core 150 to apply a new connection map. That is to say, a directed mode of operation is required when (I) one or more combinations which were previously not valid are now considered to be valid or (II) when valid connections are re-arranged. The reason for this is that suddenly adding new carriers or rearranging existing carriers can result in the disruption of those carriers which remain in service unchanged, due to the possibility of the new or rearranged optical carriers causing a sudden change in the optical amplifier gain or causing non-linear optical effects. Accordingly, as shown in FIG. 10 , the directed mode of operation is entered when an INTERRUPT message 1010 is received by the equalization processor from the switch controller 160 ′. The INTERRUPT message 1010 is indicative of the fact that a new connection map is about to be established by the switch controller 160 ′. Specifically, the INTERRUPT message 1010 contains the identity of (A) all the combinations which are currently not valid but which will become valid as a result of the upcoming change to the connection map; (B) all the combinations which are currently valid but which will become invalid as a result of the upcoming change to the connection map; and (C) all the combinations which are currently valid and which are about to be rearranged. Upon receipt of the INTERRUPT message 1010 , the equalization processor enters an initialization routine 1020 , whereupon the equalization processor proceeds to read the power estimate associated with: (i) each presently invalid but soon-to-be valid combination of wavelength and output optical fiber; and (ii) each presently valid and soon-to-be rearranged combination of wavelength and output optical fiber. The equalization processor then confirms that there is no carrier present on the combinations identified under (i) above. For the purposes of the reading the power estimate of a particular invalid but soon-to-be valid combination, it is understood that the respective intensity control signal should be set to a reasonable value (i.e., not to minimum gain/maximum attenuation). Next, the equalization processor enters a neutralization routine 1030 . Specifically, for each combination under (i) and (ii) above, the respective intensity control signal is ramped down to a value which provides minimum gain (or maximum attenuation, as appropriate). Setting the intensity to minimum gain/maximum attenuation is done in order to prevent the onset of disruptions to other carriers on the same output optical fiber upon adding the new or rearranged carrier, while the ramping down process mitigates the onset of disruptions to these other carriers during execution of the neutralization routine 1030 itself. After having completed the neutralization routine 1030 , the equalization processor sends a PROCEED message 1040 to the switch controller 160 ′, authorizing it to proceed with the establishment of the new connection map. In response to receipt of the PROCEED message 1040 , the switch controller 160 ′ applies the new connection map at step 1050 and sends an ACKNOWLEDGE message 1060 back to the equalization processor. The ACKNOWLEDGE message 1060 indicates that the new connection map has been established. In response to receipt of the ACKNOWLEDGE message 1060 , the equalization processor proceeds to execution of a ramping routine 1070 . The ramping routine 1070 consists of increasing the power level of each carrier that was neutralized in the neutralization routine 1030 , i.e., each carrier associated with (a) each previously invalid but now valid combination of wavelength and output optical fiber; and (b) each previously valid and now rearranged combination of wavelength and output optical fiber. This increase in power level can be effected by increasing the value of the intensity control signal for each VOIC associated with a previously neutralized carrier from its minimum gain/maximum loss value (previously set in the neutralization routine 1030 ) to a value which brings the corresponding individual optical carrier signal to the same optical power level as the other individual optical carrier signals sharing the same output optical fiber. As the value of the intensity control signal is being changed, the power estimates received from the power estimation module(s) will change and should therefore be given time to converge to new values. Hence, it is desirable to raise or lower the value of the appropriate intensity control signal in a gradual fashion, e.g., by ramping. The result of this ramping process will be to reduces the risk of affecting those wavelengths that already carry high speed optical data signals and that are not allowed to be disturbed. Finally, before exiting the directed mode of operation, the equalization processor executes an update routine 1080 , which consists of updating its list of valid and invalid combinations, based on the information in the INTERRUPT message 1010 . (It is recalled that this list is consulted by the equalization processor while running in scan mode.) The equalization processor subsequently returns to scan mode. Thus, through operation of the equalization processor in directed mode and interaction of the equalization processor with the switch controller 160 ′, the present invention achieves the advantage of reducing disruptions to existing carriers due to changes in the connection map involving the addition or rearranging of one or more carriers on one of more output optical fibers. Those skilled in the art will appreciate that many other embodiments are within the scope of the invention. For instance, instead of gradually decreasing and then increasing the power of each new or rearranged carrier, such carriers could be removed or introduced in an incremental fashion, i.e., in groups of one or two, etc. Thus, the neutralization routine 1030 could be represented by a process in which one intensity control signal at a time (or two intensity control signals at a time, etc.) is gradually or suddenly decreased to a minimum gain/maximum attenuation value. Similarly, the ramping routine 1070 could be replaced by a procedure whereby the affected carriers are introduced one by one without the need for ramping but with a suitable delay between the introduction of each new carrier in order to allow the power estimates to converge to new values. The gradual introduction of carriers still reduces the risk of causing a hit on those wavelengths which already carry high speed optical data signals and which should not be disturbed. FIG. 12 shows another variant of the photonic switch 400 of FIG. 4 which provides “coarse” intensity control at the input to each WDD device in the photonic switch 400 . Specifically, a tap coupler (splitter) 1220 and a VOIC 1210 intercept each input optical fiber 120 , between the respective amplifier 125 and the respective one of the WDD devices 110 A - 110 N . Each VOIC 1210 applies relatively flat gain or attenuation which affects all wavelengths on the given input optical fiber 120 to substantially the same degree. Thus, each VOIC 1210 should be capable of operating over a wider optical bandwidth than required for any of the VOICs 410 . The amount of attenuation or gain to be applied by each VOIC 1210 is encoded by a respective intensity control signal arriving along a respective intensity control line 1250 from a plurality of latches 1256 . The latches 1256 are driven by a demultiplexer 1258 that is fed by a co-processor 1254 . In the coarse equalization scheme of FIG. 12 , the amount of gain or attenuation to be applied by each VOIC 1210 is controlled such that the aggregate optical power of the optical signal on each input optical fiber 120 is approximately the same before entering the respective one of the WDD devices 110 A - 110 N . In order to measure this aggregate optical power, each tap coupler 1220 is connected by a respective optical path 1240 to a respective input of a common N-input optical switch matrix 1230 . The optical switch matrix 1230 can be identical to the switch matrices 710 , 710 ′ described with respect to FIGS. 7-9 . It consists of a plurality of mirrors which can be controllably raised or lowered in order to let through the optical signal present on a selected one of the optical paths 1240 . Control of the raising and lowering of mirrors in the optical switch matrix 1230 is achieved by the co-processor 1254 via an intervening switch driver 1235 . An output of the optical switch matrix 1230 is connected to an optical receiver 1260 , which comprises circuitry such as a photodiode and a trans-impedance amplifier for converting into electrical form the optical signal present at its input. In the embodiment of FIG. 12 , the signal received at the input to the optical receiver 1260 occupies multiple wavelengths and therefore the optical receiver 1260 must have a wide optical bandwidth of operation. The output of the optical receiver 1260 is connected to a power estimation module 1270 which can be identical to any of the power estimation modules 530 suitable for use with the embodiments of FIGS. 5 through 9 . The output of the power estimation module 1270 is fed to the co-processor 1254 . In operation, the co-processor 1254 (which can function independently of any of the processors 554 , 654 , 754 , 854 , 954 or can be integrated therewith) controls the raising and lowering of the mirrors in the optical switch matrix 1230 via the switch driver 1235 in order to obtain an aggregate power estimate, one input optical signal at a time, from the power estimation module 1270 . The co-processor 1254 then compares each received power estimate to a reference and the difference is applied to the appropriate VOIC 1210 through control of the demultiplexer 1258 and the appropriate one of the latches 1256 . Thus, the co-processor 1254 strives to maintain all the aggregate input power levels at substantially the same value in a feed-forward fashion. In general, this coarse power level adjustment will produce a significant reduction in the spread among optical power levels on a particular output optical fiber 140 , with the consequence that the dynamic range of the VOICs 410 (which are controlled by processor 554 , 654 , 754 , 854 or 954 ) can be significantly reduced. This reduction in required dynamic range allows the use of less expensive VOICs 410 in each switched demuxed optical path 180 . It is also within the scope of the invention to provide coarse power equalization at the input end in the manner of a true feedback loop as shown in FIG. 12A . For improved performance, the order of the tap couplers 1220 and the VOICs 1210 along each input of the optical fibers 120 can be reversed as shown. Greater disparities in the loss of the various VOICs 1210 can then be tolerated due to the power level measurements having been obtained via the tap couplers 1220 following (rather than before) application of intensity control by the VOICs 1210 . When designing the feedback loop, however, those skilled in the art will of course recognize that special attention must be paid to stability concerns. Those skilled in the art will also appreciate that in FIGS. 12 and 12A , the optical switch matrix 1230 and its associated switch driver 1235 can be omitted without affecting the way in which the coarse equalization scheme works. Specifically, it is within the scope of the invention to provide separate sets of optical receivers 1260 and power estimation modules 1270 in each optical path 1240 . Any individual power estimate could then be accessed by the co-processor 1254 via a common intervening multiplexer (not shown). Other coarse equalization schemes can be implemented. For example, the couplers 1220 , the optical switch matrix 1230 , the switch driver 1235 , the optical receiver 1260 and the power estimation module 1270 can be dispensed with while still providing coarse equalization at the input through the action of the VOICs 1210 . Such an embodiment is shown in FIG. 13 , where the co-processor ( 1254 in FIG. 12 ) and processor ( 554 , 654 , 754 , 854 , 954 in FIGS. 5-9 ) have been integrated into a single equalization processor 1354 in the equalizer 500 ′. As a result of the radical hardware simplification of the embodiment of FIG. 13 with respect to the embodiment of FIG. 12 , the algorithm being run by the equalization processor 1354 is slightly more complex. Specifically, the equalization processor 1354 operates in scan mode until it is interrupted by the switch controller 160 ′, whereupon the equalization processor 1354 enters a directed mode of operation. The actions performed by the equalization processor 1354 in directed mode, in respect of preparing for the appearance of a new or re-arranged carrier, remain unchanged from those described previously. However, it is the equalization processor's routine operation in scan mode which is slightly more complex because the equalization processor 1354 controls the amount of intensity variation applied by not one but both sets of VOICs 1210 and 410 . Specifically, in each pass through the algorithm in scan mode, the equalization processor 1354 does not compute the “fine” gain or attenuation to be applied by the VOICs 410 until it has computed the “coarse” gain or attenuation to be applied by the VOICs 1210 . Since the power estimates available to the equalization processor 1354 are typically post-switching power estimates, and since the coarse intensity control is performed by the VOICs 1210 prior to switching, the controller 1354 must invert the connection map applied by the controller 160 ′ in order to determine the amount of coarse intensity control it should apply at the input in order to result in a reduction in the power spread on each output optical fiber 140 . Different ways of inverting a connection map will be known to those skilled in the art. Practically, the equalization processor first determines the required gain for each individual demuxed switched optical path in the already described manner, and then determines how much of this gain or attenuation is common to all paths originating from the same input optical fiber. The common amount of intensity control is applied to the appropriate one of the VOICs 1210 and the remaining amount of intensity control for each demuxed switched optical path is applied to the appropriate VOIC 410 . In this way, the dynamic range required to be handled by the VOICs 410 can be significantly reduced, because each VOIC will only have to supply a residual amount of gain or attenuation. Thus, the hardware requirements are reduced with respect to the embodiment of FIG. 12 , at the expense of a slight increase in computational complexity with respect to the controller 1254 . Of course, a similar coarse equalization scheme can be applied at the output of the WDM devices 130 A - 130 N , prior to tapping by the couplers 420 . This embodiment is shown in FIG. 14 , where each of the output optical fibers 140 is intercepted by a respective one of a plurality of VOICs 1410 A - 1410 N placed between a respective one of the WDM devices 130 A - 130 N and the respective coupler 420 . In the case of FIG. 14 , each of the VOICs 1410 A - 1410 N applies a coarse amount of intensity control to all the wavelengths of the associated output optical fiber 140 . Hence, the equalization processor 1454 in the equalizer 500 ″ would determine the amount of required intensity control which is common to all wavelengths sharing an output optical fiber, would apply the common amount of intensity control to the appropriate one of the VOICs 1410 A - 1410 N and would apply the amount of residual gain or attenuation to the appropriate VOICs 410 . Again, the dynamic range required to be handled by the VOICs 410 can be significantly reduced, because each will only have to supply a residual amount of gain or attenuation. This can significantly reduce the aggregate cost of the VOICs 410 , at the expense of a slight increase in computational complexity with respect to the equalization processor 1454 in the equalizer 500 ″. In fact, this embodiment is even simpler than the embodiment of FIG. 12 or FIG. 13 because it does not require knowledge of the connection map through the photonic switch core 150 . Further modifications and refinements of the above-described embodiments are within the scope of the invention. In particular, it is recalled that the embodiments of FIGS. 5 , 7 and 8 employ WDD devices 510 within the equalizer 500 and the embodiments of FIGS. 7 , 8 and 9 use one or more optical switch matrices 710 , 710 ′. Due to the wavelength-dependent loss characteristics of the WDD devices 510 and due to path-dependent loss characteristics of the optical switch matrices 710 , 710 ′, it should be apparent that power level variations may be introduced by these components, depending on the specific path taken by light travelling from the couplers 420 to the equalization controller 500 . Hence, losses inherent to the measurement process itself may distort the power estimates produced by the power estimation module(s) 530 . A solution to this problem is provided in FIG. 15 , which illustrates an equalizer 1500 with a front end 1502 , an optical receiver bank 1504 , a power estimation module bank 1506 and an equalization controller 1510 which collectively encompass the embodiments previously described with reference to FIGS. 5 through 9 . Additionally, the equalizer 1500 is equipped with calibration functionality. Specifically, in order to enable the computation of the loss of each possible path from the output optical fibers 140 to the equalization controller 1510 , there is provided a calibration source 1520 for providing light of a desired wavelength and at a desired gain. The calibration source 1520 is fed by the equalization processor 1554 in the equalization controller 1510 . At the output of the calibration source 1520 is provided an (N+1)-way splitter 1530 , which sends the incoming light from the calibration source 1520 along N+1 different optical fibers 1540 A - 1540 N , 1550 . Optical fibers 1540 A - 1540 N are coupled via a respective plurality of couplers 1560 A - 1560 N to the N optical paths 425 A - 425 N leading from the couplers 420 . Optical fiber 1550 leads directly to the controller 1510 via an attenuator 1570 , an optical receiver 1580 and a power estimation module 1590 . The attenuator 1570 provides a fixed attenuation to account for the loss through the (N+1)-way splitter 1530 . In operation, the equalization processor 1554 operates in scan mode until the switch controller 160 ′ indicates that it is about to change the connection map through the photonic switch core 150 . Operation of the equalization processor 1554 in scan mode is virtually the same as previously described with reference to FIGS. 5 through 9 , with one main variation. Specifically, after evaluating the difference between a desired power level and the estimated power of a signal associated with a particular combination of wavelength and output optical fiber, the equalization controller 1510 adjusts this difference by a “calibration factor” associated with the path of that signal from the associated one of the couplers 1560 A - 1560 N to the equalization controller 1510 through the front end 1502 . The “calibration factor” associated with a path represents the inverse of the relative loss of that path. One way in which the equalization processor 1554 may determine the calibration factor of a particular path through the front end 1502 is as follows: select a wavelength; instruct the calibration source 1520 to emit at that wavelength; instruct the front end 1502 to pass through the desired wavelength along the desired path; read from the power estimation module bank 1506 the power estimate corresponding to the desired wavelength arriving along the desired path; read the power estimate received from the power estimation module 1590 ; determine the difference between the two values and store the result as the calibration factor for that particular path. The calibration factor of each path is not expected to change with time, since the properties of the components located between the couplers 1560 A - 1560 N are not expected to change. Thus, the calibration step can be performed during an initialization phase. Still, in order to apply the appropriate calibration factor, it is necessary for the equalization processor 1554 to maintain an updated mapping of which combination of output optical fiber and wavelength is associated with which path. By adjusting the intensity control signals provided to the VOICs 420 by the above-introduced calibration factors, the present invention as embodied in FIG. 15 advantageously compensates for errors which may otherwise have been introduced by the measurement process. Of course, it should be understood that the calibration is accurate to the degree that the properties of the optical receiver 1580 and power estimation module 1590 approximate those of the components in the optical receiver bank 1504 and the power estimation module bank 1506 . It should be appreciated that the calibration scheme of FIG. 15 can also be used in order to calibrate individual optical paths through either of the coarse equalization schemes previously described with reference to FIG. 12 or 12 A. The application of the calibration scheme of FIG. 15 to the coarse equalization scheme of FIG. 12A is shown in FIG. 16 , where the couplers 1560 A - 1560 N are connected to the optical paths 1240 leading from the tap couplers 1220 connected to the input optical fibers 120 . It is noted that the calibration source 1620 is a multi-colored light source which spans the same optical frequency range as any of the input WDM signals on the input optical fibers 120 . The co-processor 1654 operates as previously described with reference to FIG. 12 . However, after evaluating the difference between a desired power level and the estimated power of an input WDM signal associated with a particular input optical fiber, the co-processor 1654 adjusts this difference by a “calibration factor” associated with that input optical fiber. This “calibration factor” represents the inverse of the relative loss of the path traveled by light coming from that input optical fiber through the associated one of the couplers 1560 A - 1560 N and through the optical switch matrix 1230 . One way in which the co-processor 1654 may determine the calibration factor of a particular path through the optical switch matrix 1230 is as follows: select an input optical fiber; instruct the calibration source 1620 to emit multi-colored light; instruct the optical switch matrix 1230 to pass through any light along the selected input optical fiber; read from the power estimation module 1270 the power estimate corresponding to the selected input optical fiber; read the power estimate received from the power estimation module 1590 ; determine the difference between the two values and store the result as the calibration factor for that particular input optical fiber. The calibration factor associated with each input optical fiber is not expected to change with time, since the properties of the components located between the couplers 1560 A - 1560 N are not expected to change. Thus, the calibration step can be performed during an initialization phase. It is seen that by adjusting the intensity control signals provided to the VOICs 1210 by these calibration factors, the present invention as embodied in FIG. 16 advantageously compensates for errors which may otherwise have been introduced during measurement of the intensity of each input WDM signal. A further variation of the present invention involves placing the VOICs 410 at the input (rather than at the output) of the photonic switch core 150 . Knowledge of the connection map would then be required in order to determine which of the switched individual optical carrier signals are combined by which WDM devices 130 A - 130 N . Also, it may be desirable in such a scenario to account for the dB loss of each signal through the photonic switch core 150 , which loss would be constant so long as the connection map remains constant and would change as the connection map changes. Since this change is usually predictable to a good degree of accuracy, the equalization processor can adjust the intensity control signal supplied to each of the VOICs 410 by the respective known loss through the switch core 150 . In other embodiments of the invention, the output of the optical receivers 520 could be connected to functional units other than a power equalization system, such as a path integrity analyzer described in the co-pending U.S. patent application to Graves et al., entitled “Optical Switch with Connection Verification” and filed on even date. Of course, this assumes that the optical receivers 520 have sufficient electrical bandwidth to meet the functional requirements of the path integrity analyzer. While specific embodiments of the present invention have been described and illustrated, it will be apparent to those skilled in the art that still further modifications and variations can be made without departing from the scope of the invention as defined in the appended claims.

An optical intensity control system for use with an optical switch providing individual signal paths between input and output ports. The system has optical splitters connectable to output multiplexers of the switch and has variable optical intensity controllers (VOICs) for insertion into the individual signal paths to individually control the intensity of optical signals present in the signal paths via intensity control signals. An equalizer is connected to the splitters and to the VOICs produces an estimate of the optical power of each individual switched optical signal and generates the intensity control signals. The equalizer is adapted to controllably isolate individual switched optical signals. In this way, individual and independent control of the power on each optical channel is provided.

PRIORITY CLAIM [0001] This application claims the benefit of the filing date of Canadian Patent Application Serial No. 2,708,657, filed Jun. 28, 2010, for “Off-Road Motor Vehicle Warning System,” the entire disclosure of which is hereby incorporated herein by this reference. TECHNICAL FIELD [0002] This invention relates to vehicle warning systems and, in particular, to a traffic warning system for off-road vehicles, such as snowmobiles and all-terrain vehicles. BACKGROUND [0003] For many years, riding off-road vehicles, such as snowmobiles and all terrain vehicles (ATVs), has become a major organized recreational sport. In the province of Ontario alone, there are approximately 40,000 kilometers of snowmobile trails. Many of these trails are maintained by groomers, which are typically approximately 3 meters (10 feet) wide and thus maintain a trail width of at least 3 meters. The average off-road motor vehicle is approximately 1.3 meters (4 feet) in width. However, due to the nature of an off-road environment, many portions of such trails provide very little room for off-road vehicles to pass one another. [0004] Over the years, a hand signal courtesy protocol has evolved to avoid accidents between off-road vehicles. With a legal maximum posted speed of 50 kilometers per hour (km/hr), or in some areas 70 km/hr, the approaching speed of oncoming vehicles can exceed 100 km/hr on a trail or roadway, with little more than a few feet of clearance, leaving very little room for error. [0005] As an example of a protocol that has developed to avoid accidents, in a group of off-road vehicles such as snowmobiles or ATVs, the leader will provide a warning to oncoming traffic and the drivers in their own group by raising their left hand as a signal. For example, in a typical off-road trail protocol, the lead driver in each approaching group provides a warning of an oncoming vehicle to the others in their group that are following, by raising their left hand. The lead driver will also signal the approaching vehicle by raising a number of fingers to indicate the number of vehicles following the leader in the group. The second driver in the group does the same, and this protocol is repeated until the last driver raises a clenched fist to indicate to the oncoming vehicle that it is the last vehicle in the group. [0006] However, given the speeds of approaching vehicles, the narrow width of such trails, and the unevenness and irregular surface jutting back and forth in tracks formed by previous vehicles, this protocol still presents dangers to approaching vehicles, particularly in times of limited visibility. Furthermore, a danger is presented in this conventional method of warning oncoming vehicles by requiring the driver of each vehicle to remove one hand from the vehicle's steering means. [0007] It would be advantageous to provide a system for warning motor vehicles and others of approaching traffic or hazards, and indicating the number of vehicles approaching. BRIEF DESCRIPTION OF THE DRAWINGS [0008] In the drawings, which illustrate what is currently considered to be the best mode for carrying out the invention: [0009] FIG. 1 is a schematic view of a sensor for an off-road motor vehicle warning system embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION [0010] In an embodiment, each vehicle is provided with a warning system module, comprising a transmitter and receiver (or transceiver) and one or more warning lamps, which may be a single color or, preferably, different colors. [0011] FIG. 1 illustrates one embodiment of a transmitter-receiver according to the invention. A 12 V DC power source 10 (for example, the vehicle battery, not shown) is coupled to an indicator lamp that emits light in the visible spectrum, for example, an LED module 12 . The LED module 12 may comprise an amber LED and a green LED, or white LEDs covered by amber and green lenses. Amber would indicate “caution, approaching vehicle,” and green would indicate the last vehicle in the group to signal that the way is clear. The amber and green lamps can be in different locations on the vehicle and, in the preferred embodiment, both may flash for greater visibility. [0012] However, if desired, a single color indicator lamp of LED module 12 may be used, being white or any other selected color. If a single light color is used, it can flash as a caution indicator and remain illuminated to indicate the last vehicle in the group. [0013] The power source 10 is also coupled to a 5 V DC low current power supply 14 for powering the transmitter-receiver circuitry. Microcontroller 16 is coupled to the power supply 14 and comprises a clock circuit, which transmits pulses to power the transmitter 20 . The transmitter 20 comprises at least one infrared (IR) LED, or a plurality of IR LEDs, which may be connected in series as shown to form IR LED module 22 , which emits IR radiation at a selected IR frequency. One side of the IR LED module 22 is coupled to the power supply 14 , and the other is grounded through high-speed transistor Q 2 (which may, for example, be a MOSFET). [0014] Microcontroller 16 thus transmits a series of pulses, preferably continuously. The clock signal generated by microcontroller 16 toggles pin 5 of microcontroller 16 high and low, for example, at 38 kilohertz (KHz) generating a string of ten evenly spaced pulses followed by a short quiescent interval over 25 ms. The resulting pulses are transmitted to the gate of high-speed transistor Q 2 , which, in turn, grounds the IR LED module 22 at the selected pulse rate, causing the LEDs in LED module 22 to continuously emit a series of IR pulses at the selected pulse rate. [0015] Microcontroller 16 is also coupled to IR receiver module 30 . IR Receiver module 30 reacts to IR pulses only at the selected pulse transmit frequency (38 KHz in the example given), and does not respond to any other ambient ElectroMagnetic Radiation (EMR). The IR receiver module 30 shown in FIG. 1 , by way of example, is a Vishay model TSOP34338, which has the advantage that it does not react unless it receives at least six pulses in the selected frequency range, thereby reducing opportunities for false alarms. When the IR receiver module 30 detects at least six pulses from a transmitter 20 , the IR receiver module 30 output goes low, pulling pin 8 of microcontroller 16 low and, in turn, pulling pin 3 of microcontroller 16 high. The output of pin 3 is transmitted to the gate of Q 3 , which, in turn, grounds the visible LED module 12 causing the LEDs in module 12 to illuminate. Preferably, the clock circuitry in microcontroller 16 intervenes to toggle pin 3 between high and low states a few times each second, causing the LEDs in the visible indicator module 12 to blink for greater visibility. [0016] The operation of the invention will now be described in the context of an oncoming vehicle approaching a group of five off-road vehicles, for example, snowmobiles, all of which are equipped with the warning system of the invention. The transmitter 20 of an approaching vehicle constantly emits a series of IR pulses via IR LED module 22 , preferably confined to an arc of approximately 30 to 40 degrees directly in front of the vehicle. When the first vehicle in the group comes into range of the approaching vehicle, the IR signal is received by the IR receiver module 30 of the first vehicle in the group. The first vehicle's IR receiver module 30 detects the IR pulses from the oncoming vehicle at the selected transmit rate, causing microcontroller 16 to emit a signal to Q 3 so that visible indicator lamp of LED module 12 on the first vehicle in the group illuminates (preferably, the signal to Q 3 is pulsed, causing visible indicator lamp 12 to flash). The second, third and fourth vehicles' IR receiver modules 30 each respectively react in the same fashion upon coming into range of the signal transmitted from the approaching vehicle. [0017] The fifth (last) vehicle in the group has preferably set its visible indicator module 12 to “trailing vehicle” mode, which is distinct from the visible indicator module 12 of the first four vehicles in the group. For example, where amber and green indicator lamps are used, both preferably flash for greater visibility, but in the normal (front or intermediate vehicle) warning mode, the amber light is enabled and flashes, whereas in the “trailing vehicle” mode, the green light is enabled and flashes. Where a single color of indicator light is used, the visible indicator module 12 of the vehicle in the “trailing vehicle” mode may provide a continuous signal (rather than a flashing signal, as in the case of the front and intermediate vehicles), to indicate to the approaching vehicle that the fifth vehicle is the final vehicle in the group. A driver of the approaching vehicle, seeing the normal warning light (flashing amber, in the two-color embodiment described above), therefore, knows that there are more vehicles in the group that it is approaching and about to pass, and can react to pass safely on a narrow trail. There is no reduction in control, as is the case when hand signals are used, because in the case of all vehicles, both of the driver's hands can remain on the vehicle steering actuator (such as handle bars, a steering wheel, etc.). [0018] Slow moving vehicles such as groomers on an off-road trail can be provided with a similar warning module, optionally providing a different colored visible indicator light 12 , which would instantly indicate to an approaching vehicle that it is approaching a slow moving, and typically wide, grooming vehicle. The driver of the approaching vehicle can react accordingly. Advantageously, the grooming vehicle may have multiple transmitters, allowing it to transmit its signal over a wider arc. Optionally, the grooming vehicle transmitter circuit 42 transmits at a different frequency or signal pattern from vehicles using the trail to activate the warning indicator lamp 12 of approaching vehicles; a second receiver module (not shown) on the approaching vehicle, responsive to the unique grooming vehicle frequency or signal pattern could activate a different colored light on the approaching vehicle, or an audible indicator such as a buzzer or siren, to indicate to the driver of the approaching vehicle that it is approaching a grooming machine (or some other trail hazard). [0019] The electronics may be powered by the off-road vehicle battery, a separate battery or solar power. [0020] Portable warning modules can be provided with a portable power source, such as a battery or solar power, and placed along the trail to warn of stationary hazards on the trail, such as a washed out portion, open water crossing, ice, logging trucks, disabled equipment, etc. [0021] Other potential uses for the warning system of the invention include: construction, particularly road construction; train movement; fire response team and other such road hazards. It can also be used on multi-user trails for hikers, cross-country skiers, snowshoers and horseback riders, who could carry a transmitter or a transmitter-receiver of the invention to warn vehicles of their presence. The device of the invention can also be installed in vehicles as a safety device to warn of intruders, or to prompt inspection of a vehicle such as a school bus to assure that all children have exited at the end of a trip. [0022] Various embodiments of the present invention having been thus described in detail by way of example, it will be apparent to those skilled in the art that variations and modifications may be made without departing from the invention.

A warning system for vehicles that comprises a transmitter and a receiver for respectively transmitting a signal to an approaching vehicle or receiving a signal from an approaching vehicle. A light actuated upon receiving a signal from another vehicle and visible to the other vehicle indicates to the other vehicle that it is approaching a vehicle.

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority of U.S. Provisional Patent Application Ser. No. 60/787,214, filed Mar. 30, 2006. The disclosure of the prior application is hereby incorporated by reference in its entirety. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a node and more specifically but not exclusively to a node within a mobile communications device. 2. Description of the Related Art User equipment have become application rich personal devices capable of more than voice communication. It is for example difficult to purchase user equipment which does not feature a digital camera connected to internal digital image processing elements, polyphonic audio synthesizing equipment. It is also common for user equipment to be connected or incorporate advanced features such as satellite navigation and audio and video recording and playback. In order that the components of the user equipment can communicate with each other user equipment is equipped with a communications link or network designed in such a way that internal systems can communicate with each other to generate this functionality, and that external systems can also be connected to the user equipment, to enable the user equipment to be upgradeable. A known example of such a communication network is the serial interface known as D-Phy (proposed by the mobile industry processor interface alliance (MIPI)). The D-Phy serial interface supports as many as four lanes operating at rates up to 1 Gbit per second per lane and uses low-voltage, source-synchronous, scalable-signalling technology. Operating on these physical networks are protocol stacks. The protocol stacks define how data is transmitted across the physical network. For example the MIPI unified protocol (UniPRO) defines standards for transmitting data packet over the D-Phy network. The current MIPI UniPRO standards and the protocols used by other proprietary user equipment networks suffer from the problem of data integrity—in other words relying that the data transmitted by the data originator (or first end node) of the network has been received and is being processed by a data final destination (or second end node). In these networks the nodes have a limited capacity for receiving and processing data. Thus when the final destination node reaches the capacity the node can not physically receive or process the any further data transmitted through the network. In these situations the typical network protocol allows implements either a stop or discard process. The stop process instructs the final destination node to stop accepting traffic from the network. This results in “head of line blocking” where the data being transmitted is queued in the network nodes between the two end nodes. This queued data causes the network nodes to effectively block the node from passing any further data until the next node accepts the current data packet. This blocking therefore propagates from the final destination node to the originator node resulting in partial or full blocking of the network. The discard process instructs the final destination node to drop a packet. This allows the network to operate efficiently and without blockage, but results in a loss of end-to-end (E2E) reliability as even if the data is reaches the final destination node the data can not be guaranteed to have received and processed the data. Point-to-point (P2P) data flow control is known. In such systems the data transmitted between two immediate nodes can be acknowledged to confirm its receipt. These P2P systems can be divided into two groups. The first group employs flow control without synchronisation information by using flow control tokens. One example is the Spacewire system. These systems have further problems in that they are required to employ complex mechanisms for recovering loss of the flow control tokens. Furthermore it is difficult to estimate the data overhead of transmitting control tokens which prevent such systems from producing accurate quality of service provisions in bandwidth limited networks. The second group of P2P systems operate flow control with synchronisation information. These typically apply techniques synchronising the flow control information at both ends with every flow control signalling packet and therefore are complex and require a greater signalling overhead than the token based group. An example of this synchronised flow control signalling can be found the P2P flow control mechanism featured within the current MIPI UniPRO specifications. Using the P2P flow control mechanisms for both point-to-point and end-to-end reliability produces additional complexity with regards to signalling overhead and complexity of nodes within the network whilst producing a system which is not optimal for end-to-end flow control. SUMMARY OF THE INVENTION Embodiments of the present invention aim to address or at least partially mitigate the problems disclosed above. According to a first aspect of the invention there is provided a node arranged to communicate with at least one further node; comprising: a buffer arranged to receive data transmitted from the at least one further node; an output arranged to transmit data to the at least one further network element, wherein the data comprises information about the ability for the buffer to receive further data transmitted from the further node. The node may further comprise a detector arranged to indicate capacity within the buffer to receive the data from the at least one further node; The data transmitted to the at least one further node may be a data packet. The information about the ability for the buffer to receive further data transmitted from the further node is preferably an end-to-end flow control signal. The node is preferably arranged to communicate over a network within an user equipment. The node is preferably arranged to communicate over a network at least partially external to an user equipment. The network is preferably a D-Phy network. The data packet may be a UniPRO standard data packet. The information about the ability of the buffer to receive further data transmitted from the further node is preferably located within the ATyp=xx field of the UniPRO standard data packet. The information about the ability of the buffer to receive further data transmitted from the further node is preferably the binary value 01 in the ATyp=xx field. The data may comprise a header and a payload, wherein the information about the ability for the buffer to receive further data transmitted from the further node is located within at least one of: the header and the payload. The detector is preferably arranged to indicate when the capacity of the buffer is greater than or equal to a predetermined capacity value. The predetermined capacity value is preferably transmitted to the node on initialisation of the communication with the at least one further node. The node may further comprise reservation logic for reserving the predetermined capacity value within the buffer. According to a second aspect of the invention there is provided a node arranged to communicate with at least one further node; comprising: an input arranged to receive information about the ability for a buffer of the at least one further node to receive further data transmitted from the node; a detector arranged to detect the information; a counter arranged store a value to indicate the ability of the at least one further node to receive further data packets transmitted from the node; an output arranged to transmit further data to the further node dependent on the counter value indicates that the at least one further node has the ability to receive the further data. The reception of the information about the ability for a buffer of the at least one further node to receive further data is preferably arranged to increment the counter value. The counter is preferably arranged to increase the counter value dependent on the information about the ability for a buffer of the at least one further node. The counter is preferably arranged to decrement the counter value when the output transmits further data to the at least one further node. According to a third aspect of the invention there is provided a network comprising at least one node as claimed latterly and at least one node as also described formerly. According to a fourth aspect of the invention there is provided a network comprising a first node and at least one further node, wherein information is provided within data comprising a payload transmitted at least one of the first node to the at least one further node and from the at least one further node to the first node. According to a fifth aspect of the invention there is provided a method for communicating between a first node and at least one further node in communication over a network, comprising the steps of: transmitting from the first node to the at least one further node data comprising information about the ability of the first node to receive further data transmitted from the further node, and receiving at the at least one further node the data comprising information about the ability of the first node to receive further data transmitted from the further node. The method may implement an end-to-end flow control mechanism The method may further comprise the step of: incrementing a counter value within the at least one further node dependent on the reception of data comprising information about the ability of the first node to receive further data transmitted from the further node. The step of incrementing the counter value may increment the counter value dependent on the value of the information. The method may further comprise the steps of: transmitting further data from the at least one further node to the first node dependent the counter value; and decrementing the counter value. The step of decrementing the counter value may decrement the counter value dependent on the size of the further data transmitted from the at least one further node to the first node. According to a sixth aspect of the present invention there is provided a computer program arranged to operate a computer for communicating between a first node and at least one further node in communication over a network, comprising the steps of: transmitting from the first node to the at least one further node data comprising information about the ability of the first node to receive further data transmitted from the further node, and receiving at the at least one further node the data comprising information about the ability of the first node to receive further data transmitted from the further node. BRIEF DESCRIPTION OF THE DRAWINGS For better understanding of the invention, reference will now be made by way of example to the accompanying drawings in which: FIG. 1 shows a schematic view of a user equipment network over which embodiments of the present invention may be implemented; FIG. 2 shows a schematic view of the data flow as produced by the present invention; and FIG. 3 shows a schematic view of a E2E flow control signal embedded in a data packet as employed by embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention relate particularly but not exclusively to MIPI UniPro architecture on top of D-Phy network as employed in user equipment. Embodiments of the invention may be applicable to other user equipment networks for connecting elements within user equipment. For example other embodiments may be employed for use over the Nokia proprietary discobus architecture. Reference is made to FIG. 1 which shows a user equipment comprising several component subsystems connected together via the D-Phy network 51 . For clarity components of the user equipment not directly concerned with the present invention are not shown. It should be appreciated that while embodiments of the invention have been described in relation to user equipment such as mobile stations, embodiments of the invention are applicable to any other suitable type of user equipment. In this document the term, terminal, where used is intended to cover all the examples of user equipment described. The term user equipment can apply to any appropriate mobile device adapted for communication to a wireless cellular communications network. For example, the mobile user equipment may access the cellular network by means of a Personal computer (PC), Personal Data Assistant (PDA), mobile station (MS) and so on. The network 51 comprises a series of nodes 53 which act as switches or routers for receiving and distributing packets in a known manner. The network 51 is also shown connected to a series of processors or sub-systems for carrying out various processes or applications associated with the user equipment. For example, the network is connected to a communications processor 3 (for communicating with the cellular network), an applications processor 5 (arranged to controlling the operation of applications), a radio/TV processor 7 (arranged to receive either analogue/digital radio/TV signals), a Bluetooth processor 9 (arranged to receive and transmit Bluetooth data over a Bluetooth communications channel), a camera sub-system 11 arranged to receive and transmit digital image data from the camera (the camera in some embodiments be connected to the network and transmit raw data to the camera sub-system 11 ), an audio sub-system 13 (arranged to transmit audio data for example MP3 audio data), and a I/O sub-system 15 connected to the earpiece/speaker 17 and the microphone 19 . These processors/subsystems described are examples only and some embodiments of the present invention may have more or fewer sub-systems connected to the network 51 . Furthermore in some embodiments at least one sub-system is connected to the network 51 via an external connection not shown in FIG. 1 . As has been described previously P2P flow control can be used by the network 51 , so that each sub-system or network node can guarantee that the packet integrity between nodes. With regards to FIGS. 2 and 3 an End-to-End flow control (E2E FC) mechanism, embodying the present embodiments of the invention, is described with respect to a D-Phy network. With regards to FIG. 2 the data flow of an embodiment of the E2E flow control mechanism is shown. FIG. 2 shows two network end nodes, node A 251 and node D 257 , in communication with each other via intermediate nodes, node B 253 and node C 255 . At least one of the end nodes comprising, a output for transmitting data to the network, an input for receiving data from the network, a buffer connected to the input for storing the received data, and a detector (such as a pointer) arranged to indicate the capacity within the buffer to receive further data. Furthermore the other end node comprises a counter indicating the capacity of the end node. The other end node comprises an input arranged to receive data from the network, an output for transmitting data to the network, data processing means, which can be hardware, software or a combination thereof, arranged to detect or evaluate the counter value and allow or stop the other end node from transmitting data containing a payload to the end node. In a network arranged for duplex (two-way) communication system both end nodes comprise both sets of elements described above. The arrangement described hereafter demonstrates an example of the flow control mechanism as implemented within an embodiment of the invention, and it would be understood by the person skilled in the art that the two end nodes could be connected directly together or separated by any number of intermediate nodes in further embodiments. The steps 151 to 161 describe the ‘crediting’ E2E flow control steps, or ‘credit’ cycle. In other words the situation when a first end node indicates to another end node that there is free space on the first end node. The steps 163 to 171 describe the ‘debiting’ E2E flow control steps, or ‘debit’ cycle. The ‘debit’ cycle is the situation when the node uses the ‘credit’ allocated to the node to transmit data packets. In step 151 the network end node A 251 determines that it has capacity to receive at least one portion of data (or has at least one ‘free-space’ for data). This in an embodiment of the invention can be implemented by a pointer or pair of pointers pointing to memory locations in a buffer. The number of memory locations between a read and write pointer in a buffer can indicate the presence and amount of free memory available. In step 153 , in response to this determination, end node A 251 transmits via its output an E2E flow control signal to node B 253 (the E2E flow control signal is addressed to end node D 257 but has to initially be transmitted to intermediate nodes B 253 and C 255 ). The transmission of the E2E flow control signal is represented in FIG. 2 by the solid line with an arrowhead showing the direction of transmission. Node B 253 receives the E2E flow control signal and using a conventional P2P flow control mechanism (such as the transmission of an acknowledgement message to the transmitting node) confirms to end node A 251 that the E2E flow control signal has been successfully received by node B 253 . The P2P flow control mechanism is represented in FIG. 2 by the dashed line with an arrowhead showing the direction of the acknowledgement message. In step 155 , after transmitting the E2E flow control signal, node A reserves the free space in the receiver or processor buffer so that only packets received originating from end node D 257 can be stored in the reserved free space. This can be implemented within a buffer by a pointer pointing to a memory location within a buffer which points to the next unreserved memory location. In step 157 node B 253 transmits the E2E flow control signal to node C 255 . Node C 255 receives the E2E flow control signal from node B 253 and using a conventional P2P flow control mechanism (such as the transmission of an acknowledgement message to the transmitting node) confirms to node B 253 that the E2E flow control signal has been successfully received by node C 255 . In step 159 node C 255 transmits the E2E flow control signal to end node D 257 . Node D 257 receives the E2E flow control signal from node C 255 and using a conventional P2P flow control mechanism (such as the transmission of an acknowledgement message to the transmitting node) confirms to node C 255 that the E2E flow control signal has been successfully received by node D 257 . Providing the P2P flow control mechanism within the network is operational and not producing erroneous results, end node A 253 can assume that the E2E flow control signal has been correctly transmitted to end node D 257 . In a further embodiment of the invention, a further safeguard is implemented. In this embodiment end node D 257 , on receiving the E2E flow control signal, transmits to end node A 251 via the nodes C 255 and B 253 an acknowledgement message confirming the successful receipt of the E2E flow control signal. In step 161 , end node D 257 on receipt of the E2E flow control signal increments an internal counter. The internal counter indicates the ‘credit’ limit of the end node A, in other words the amount of free-space reserved at node A 251 for node D 257 data. In step 163 , end node D 257 determines that is has a data packet to transmit to end node A 251 . End node D 257 then examines the value stored in its internal counter. If the counter is equal to zero, and therefore there is no indicated free space, then the method passes to step 163 a . In step 163 a end node D 257 does not transmit any packets to end node A and will pass back to step 163 to check the internal counter at some time later. In some embodiments of the invention the end node D waits a predetermined or random time period before performing the internal counter check again, in other embodiments of the invention the end node D only checks the internal counter after receiving an E2E flow control signal. If the counter is not equal to zero, then the method passes to step 165 . In step 165 , end node D 257 transmits a data packet to node C 255 (the packet is addressed to end node A 251 but has to initially be transmitted to intermediate nodes B 253 and C 255 ). The transmission of the packet is represented in FIG. 2 by the thick line with an arrowhead showing the direction of transmission. Node C 255 receives the packet and using a conventional P2P flow control mechanism (such as the transmission of an acknowledgement message to the transmitting node) confirms to end node D 257 that the packet has been successfully received by node C 255 . The P2P flow control mechanism is represented in FIG. 2 by the dashed line with an arrowhead showing the direction of the acknowledgement message. In step 167 node C 255 transmits the data packet to node B 253 . Node B 253 receives the data packet from node B 255 and using a conventional P2P flow control mechanism (such as the transmission of an acknowledgement message to the transmitting node) confirms to node C 255 that the data packet has been successfully received by node B 253 . In step 169 node B 253 transmits the data packet to end node A 251 . Node A 251 receives the data packet, via the node input, from node B 253 and using a conventional P2P flow control mechanism (such as the transmission of an acknowledgement message to the transmitting node) confirms to node B 253 that the data packet has been successfully received by node A 251 . In step 171 end node D decrements the internal counter value. In a further embodiment of the invention, a further safeguard is implemented. In this embodiment end node A 251 , on receiving the data packet, transmits to end node D 257 via the nodes C 255 and B 253 an acknowledgement message confirming the successful receipt of the data packet. It is then in response to this step that the end node D decrements the internal counter. Thus providing the P2P flow control mechanism within the network is operational and not producing erroneous results, end node D 257 can assume that the data packet has been correctly transmitted to end node A 251 . Furthermore the E2E flow control mechanism as described above also enables the end node D to assume that the data packet is also not simply going to be discarded by end node A even if it has been correctly transmitted to end node A 251 . Each E2E flow control signal received by the end node provides the end node with the permission to sending one portion of data. The size of one portion or the ‘free space’ can be set dependent on each connection—for example to be dependent on the buffer sizes of the end nodes or the intermediate nodes. In some embodiments of the invention this is determined during the initial connection establishment procedure. In other embodiments of the invention the portion size or ‘free-space’ is set using a preconfigured connection setting. Although FIG. 2 shows a ‘debit’ cycle (i.e. a transmission of a data packet) immediately following a ‘credit’ cycle (i.e. the transmission of a E2E flow control signal) it would be understood by the person skilled in the art that at least two ‘debit’ or ‘credit’ cycles can be implemented without intervening ‘debit’ or ‘credit’ cycles respectively. For example end node A 251 after reserving the portion or ‘free-space’ size at the end node A 251 after detecting further sufficient capacity for a further portion could transmit a further E2E flow control signal to the end node D 257 before the end node D transmits a data packet. In some embodiments of the invention where the network is a true duplex network the ‘debit’ cycles and ‘credit’ cycles can be implemented concurrently, for example providing that there is sufficient credit (i.e. the internal counter is not equal to zero) node D 257 transmits a data packet to end node A 251 , whilst on detecting sufficient capacity in end node A 251 transmits an E2E flow control signal to end node D 257 . The above ‘credit’ cycle from node A 251 to end node D 257 describes the situation where a connection has been established. In such a system the end node D 257 does not initially know the end node A 251 capacity and is only informed of it by the transmission of E2E flow control signals. If the capacity of end node A is high for example after resetting the user equipment, the establishment of the connection or after flushing the buffer, the data packet rate from end node D 257 to end node A 251 is lower than the optimal rate as node D 257 awaits E2E flow control signals before sending data packets. In some embodiments of the invention an E2E flow control signal is transmitted with the connection establishment confirmation and at the connection restart after reset. This E2E flow control signal is interpreted by the end node as a full buffer ‘credit’ i.e. permission to use the full buffer capacity of the other end node. In such embodiments the end node determines the other end node's buffer size (for example all end nodes of the network can have a predefined minimum buffer size—which is used as the initial counter value, or the buffer size is transmitted as part of the connection establishment message—which is then used as the initial counter value). FIG. 3 shows one possible implementation of the E2E packet data unit (PDU) 51 . The PDU comprises a header 301 , body 303 and tail portion 305 . The header 301 comprises the fields: ESC_DL which is a special code, which allows to distinguish control symbols from data symbols, SoF which is a code that tells that this control symbol starts a new frame, TC/PLx which defines the traffic class or priority level field which identifies to which priority group the frame belongs (has direct impact on the treatment procedure in both ends of the link), Rsv which is a reserved field, Ext=x which is an extension bit which permits packet header to be extended (this bit is set to 0 for conventional header length, but is set to 1 to indicate an extension of the header into the first symbols of the payload, EoM which indicates that this frame is the last frame of the Transport layer message (which for transmission over the network might be split to a number of Datalink layer frames), CportID which is the unique ID number of a port at the destination device within a stack of ports for Connection Oriented applications, and DeviceID which is the unique address of the destination node. The header also comprises the ATyp=xx field 311 , where xx is a pair of binary values. The body 303 of the datagram is contains the payload field, the payload is typically the data to be transmitted. The tail 305 of the datagram comprises the fields: ESC_DL, EoF odd/even which indicates that this is the last control symbol of the frame, Frame sequence number which is a sequence number of the frame in the Datalink layer transmission, which is used for providing P2P reliability, and CRC16 which is a 16 bit cyclic redundancy check value of the payload data. In embodiments of the invention the E2E flow control signal is stored as a value of the ATyp=xx header field 311 or by not currently used by the data packet for any other use. For example The value in an embodiment to indicate that the data packet contains an E2E flow control signal is where the data packet header field has a value ATyp=01. As can be appreciated the E2E flow control signal embedded within the UniPRO data packet structure has a further advantage in that the E2E flow control signal can be transmitted as part of a data packet from one end node to the other end node. In such an embodiment the ‘credit’ cycle for the link from end node A 251 to end node D 257 can be embedded within the ‘debit’ cycle for the link passing the opposite way—in other words from end node D 257 to end node A 251 . Where data traffic is unequal or one-directional the data packets containing the E2E flow control signal can be transmitted by transmitting an empty packet (i.e. a data packet that contains only a header and tail and with no payload). Thus embodiments of the invention proposes an E2E flow control mechanism which is both efficient (the signalling overhead being contained with data being transmitted by the return path) and is also robust (the embodiments of the invention use the P2P flow control mechanisms implemented with regards to data packet transmission), and with minor modification of the end node logic (the end nodes are required to examine one of the data packet fields and to comprise a counter which is modified on transmission of payload containing packets to the end node and receipt of packets comprising predetermined header values). The embodiments further results in a minimal increase of the signalling overhead and under certain conditions do not even introduce additional overhead at all. Comparing to the embodiments of the present invention against prior art solutions, the embodiments are more efficient in respect of all consumed resources—implementation gate count, power consumption, and signalling overhead. Furthermore the amount of E2E flow control signalling overhead is predictable, which enables the maintenance of Quality of Service guaranties for networks with bandwidth reservation. As will be appreciated by the person skilled in the art, although FIG. 3 shows the E2E flow control signal being embedded within a UniPRO datagram and specifically within the ATyp=xx header field 311 , it would be appreciated that the E2E flow control signal could be embedded within a different part of the datagram. In a further embodiment of the invention the E2E flow control signal could be embedded within the data packet payload. In further embodiments of the invention the UE network is a serial network other than a Phy-D network and the protocol used to transmit packets is other than the UniPRO standard used to transmit UniPRO packets as shown in FIG. 3 . In these embodiments the E2E flow control signal from a first end node to another end node containing permission for the another end node to transmit data from the another end node to the first end node is embedded within a data packet transmitted over the serial network from the first end node to the another end node. In further embodiments of the invention the E2E flow control signal contains an E2E flow control value used by the end node to increment the counter. In one of these embodiments the value is used to set the counter to the value. In further embodiments of the invention the value is used to increment the counter by that value. In some embodiments the flow control signal is capable of being modified. In other embodiments of the invention the flow control signal is modified ‘on the fly’ i.e. during the communication process. The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.

A node configured to communicate with at least one further node. The node includes a buffer configured to receive data transmitted from the at least one further node. The node also includes an output configured to transmit data to the at least one further network element. The data includes information about the ability for the buffer to receive further data transmitted from the further node.

PRIORITY The present Application claims benefit of priority to U.S. provisional application 61/523,672 filed on Aug. 15, 2011, the entire contents of which are hereby incorporated by reference. TECHNICAL BACKGROUND A key challenge to high resolution imaging sensors used in observing terrestrial activities over a very wide field-of-view (WFOV) (e.g., 50 km 2 ) is to achieve the resolution needed to observe and make inferences regarding events and objects of interest while maintaining the area coverage, and minimizing the cost, size, weight, and power of the sensor system. One particularly promising approach to the data deluge problem is compressive sensing, which involves collecting a small amount of information-rich measurements rather than the traditional image collection from a traditional pixel-based imager. There is no current solution for compressive sensing architectures, especially in the infrared. An eyelid technology, liquid crystal (LC), and microelectromechanical system (MEMS) digital mirror arrays (DMA) have been postulated as potential solutions in a lab environment, but there is no current hardware available. The closest technology to production scale is a visible/short wave infrared compressive sensing camera that uses the DMA array, but this is a reflective design. A DMA solution is limited in resolution by the number of pixels and also to a ±degree tilt in the reflective element(s). Also, the solution is complex and failure-prone due to the complex optics, and the sampling modulation is limited. SUMMARY Aspects of the techniques and solutions disclosed herein are directed at coded masks that include phase change material (PCM). Such masks may be suitable for use with various types of photo-detectors, such as photo-detectors of the type disclosed in U.S. Pat. No. 7,687,871, issued to Shimon Maimon on Mar. 30, 2010, the entire contents of which are hereby incorporated by reference. Other detector types, such as p-n junction detectors, photodiodes, charge-coupled device (CCD) photodetectors, active-pixel sensors/CMOS sensors, and other detector types. Wavelengths detected by the photodetector and/or filtered or otherwise affected by a coded PCM mask applied to the detector may include long-wave, mid-wave, and/or short-wave infra-red, millimeter-wave, visible spectrum, and/or ultra-violet radiation. Aspects of the techniques and solutions discussed herein may pertain to a pixel-level mask for a photo-detector, the mask comprising: a layer of reconfigurable phase-change material (PCM) configured to vary between a first refractive index and a second refractive index; said PCM layer being divided into individual pixel areas such that each individual pixel area may be set to have the first refractive index or the second refractive index; said PCM layer being disposed on a photo-detector such that incident radiation detected by the photo-detector must pass through the PCM layer in order to be detected; and a PCM controller that controls the refractive index of an individual pixel area. In some variations, each pixel area may have a refractive index within a range of values between the first refractive index and the second refractive index, inclusive. In some variations, the PCM includes Ge2Sb2Te5 (GST); the first refractive index is associated with a crystallized state of GST; and the second refractive index is associated with an amorphous state of GST. In some variations, the PCM controller includes a voltage source; and the PCM controller is operably connected to an individual pixel area such that a first voltage level provided by the controller sets the individual pixel area to have the first refractive index and a second voltage level provided by the controller sets the individual pixel area to have the second refractive index. In some variations, the mask includes a voltage source operably connected to the PCM controller; the PCM controller includes a multiplexer PCM controller; and the PCM controller controls the voltage source such that the voltage source provides a first voltage level that sets an individual pixel area to have the first refractive index and such that the voltage source provides a second voltage level that sets the individual pixel area to have the second refractive index. In some variations, the first voltage level is six volts. In some variations, the individual pixel areas are aggregated into superpixels. In some variations, the superpixels are controlled by the PCM controller such that each superpixel may be set to have a particular imaging mask pattern by changing the refractive indices of the pixel areas within each superpixel. In some variations, each superpixel in the mask is the same size and shape. In some variations, a superpixel corresponds to a pixel of the underlying photo-detector. In some variations, the mask includes a laser source; the PCM controller is operably connected to the laser source; the laser source provides a first laser irradiation to the individual pixel area to set the individual pixel area to the first refractive index and a second laser irradiation to the individual pixel area to set the individual pixel area to the second refractive index. In some variations, the first laser irradiation is continuous wave (CW) irradiation and the second laser irradiation is pulsed irradiation. In some variations, the photo-detector is an infra-red detector; the superpixels the PCM layer correspond to pixel areas of the infra-red detector; the pixel areas having the first refractive index are opaque to infra-red radiation; and the pixel areas having the second refractive index are transparent to infra-red radiation. In some variations, the pixel areas having the first refractive index and the pixel areas having the second refractive index are arranged to form an imaging mask for compressive imaging. In some variations, the mask includes an index variation layer of ZnS—SiO2 disposed beneath the PCM layer; a layer of Aluminum disposed beneath the response variation layer; and a layer of glass disposed beneath the layer of Aluminum; where the photo-detector is disposed beneath the layer of glass such that incoming radiation to be detected by the photo-detector must pass through the PCM layer, the index variation layer, the Aluminum, and the glass before being detected by the photo-detector. In some variations, the mask includes a layer of doped silicon and/or alumina disposed beneath the PCM layer, where switching properties of the mask are determined based on a thickness of the doped silicon and/or alumina layers. In some variations, the PCM controller controls a pattern of the imaging mask by selectively changing refractive indexes of individual pixel areas. In some variations, PCM controller includes a laser source; the laser source providing a first laser irradiation to the individual pixel area to set the individual pixel area to the first refractive index; and the laser source providing a second laser irradiation to the individual pixel area to set the individual pixel area to the second refractive index. Aspects of the techniques and solutions discussed herein may pertain to method of controlling the absoption of individual pixel areas in a reconfigurable phase-change material (PCM) mask for a photo-detector, the method comprising: first illuminating at least one pixel area with a continuous wave (CW) laser illumination to increase the absorption of said at least one pixel area from a first value up to a second value; and second illuminating said at least one pixel area with a pulsed laser illumination to set the absorption of said at least one pixel area to the first value; where said first illuminating and said second illuminating are performed selectively on individual pixel areas in the PCM mask to set a mask pattern. Aspects of the techniques and solutions discussed herein may pertain to a method of controlling the absoption of individual pixel areas in a reconfigurable phase-change material (PCM) mask for a photo-detector, the method comprising: first providing at least one pixel area with a SET voltage level to increase the absorption of said at least one pixel area from a first value up to a second value; and second providing said at least one pixel area with a RESET voltage level to set the absorption of said at least one pixel area to the first value; where said first providing and said second providing are performed selectively on individual pixel areas in the PCM mask to set a mask pattern. Further scope of applicability of the techniques, devices, and solutions described herein will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the techniques, devices, and solutions described herein, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this detailed description. BRIEF DESCRIPTION OF DRAWINGS The techniques, devices, and solutions described herein will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present disclosure, and wherein FIG. 1 a depicts a variation of a PCM coded mask as described herein; FIG. 1 b depicts a variation of a PCM coded mask as described herein; FIG. 1 c depicts a variation of a PCM coded mask as described herein; FIG. 1 d depicts a variation of a PCM coded mask as described herein; FIG. 2 a depicts a variation of a PCM coded mask as described herein; FIG. 2 b depicts a variation of a PCM coded mask as described herein; FIG. 3 a depicts a variation of refraction index changes in a PCM material; FIG. 3 b depicts variations of reflectivity changes in variations of a PCM material. The drawings will be described in detail in the course of the detailed description. DETAILED DESCRIPTION The following detailed description of the invention refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Also, the following detailed description does not limit the techniques, devices, and solutions described herein. Instead, the scope of the techniques, devices, and solutions described herein is defined by the appended claims and equivalents thereof. In a solution to the above-noted problem, phase change materials (PCM) may be used as the active components to create coded apertures (i.e. sub-pixel/sub-wavelength patterns), which in, combination with image read-out and processing algorithms, optimize the “best” possible compressible image that fits the observed measurements for perfect image reconstruction. In some variations, a PCM coded mask may be disposed onto a focal plane array (FPA) such as an infra-red (IR) detector. Other variations may use different types of detectors, such as detectors that operate in some or all of the visible, millimeter-wave, and infra-red spectra. A variation of a PCM coded mask disposed over a pixel array is shown in FIG. 1 a. In the variation shown, a pixel array 1001 such as an FPA may include several individual pixels 1020 . A PCM coded mask 1010 may be disposed over the FPA 1001 . In some variations, the PCM coded mask may include several mask PCM elements 1030 . In some variations, many mask PCM elements 1030 may cover one FPA pixel 1020 . In other variations, a PCM coded mask may be a continuous surface configured for sub-pixel variations in mask structure. In some variations, a PCM coded mask can be used in the Fourier planes as well as in the image plane. In such variations, the PCM coded mask will result in the detection of the image convolved with the PCM mask. For applications in compressive sensing, this would be particularly useful for image sparse images (i.e. imaging objects of interest against a bland background). In some variations, a PCM coded mask may be used to generate one or more masks for compressive sensing applications. Such a variation of a mask is shown in FIG. 1 b . In the variation shown, a PCM film 1110 may be divided into discrete regions 1100 , 1120 which may correspond to pixels on an underlying photodetector (not shown). The film regions may then each be set or otherwise configured to have particular transmission properties. Some film regions may be set to transmit or pass 1120 a certain wavelength or wavelength range. Other film regions 1100 may be set to suppress that wavelength or wavelength range. In further variations, the suppressive regions 1100 may suppress or otherwise reject all incoming radiation that could/would otherwise be detected by an underlying photodetector. In such variations, the PCM film 1110 may be arranged into a compressive imaging mask such that only the transmissive regions 1120 of the mask allow electro-optical radiation to pass through for detection by an underlying photodetector (such as, for instance, an infra-red detector). In some variations, a PCM film may be used in combination to other non-active materials such as alumina on a film stack, to generate masks for a compressive sensing application. In variations where the PCM coded mask elements correspond to one or more particular pixels on an underlying FPA, each individual element or array of elements in the mask (e.g. row or column) can be individually addressed by an external laser or voltage stimuli allowing the PCM material to change its transmission properties. In some variations, this is accomplished by causing the PCM material to change between crystalline and amorphous states; which in turns produces a change in the optical properties of the material (e.g. refractive index, absorption, etc). In some variations, these changes can occur in the nanosecond response time. A variation of such a PCM mask is shown in FIG. 1 c . In the variation shown, each element 1210 , 1220 or the PCM mask 1230 corresponds to one pixel of an underlying photodetector. In the variation shown, the percentage of light transmitted through each pixel 1210 , 1220 of the PCM mask 1230 can be adjusted by controlling an input voltage directed to that pixel 1210 , 1220 by a multiplexer PCM controller 1200 . In some variations, the application of a bias voltage (SET pulse) to a pixel 1210 crystallizes the material and a different bias (RESET), or further increasing the bias voltage, may cause the material to re-amorphize. In other variations, the PCM material may be placed in a crystalline state by a particular voltage pulse and may be triggered to change to an amorphous state by a different voltage pulse. In some variations, a SET pulse may be ˜6 volts and a RESET voltage may be ˜10 volts. In some variations, the multiplexer PCM controller 1200 may be a specialized or otherwise distinct component of an overall PCM mask device. In some variations, such a multiplexer PCM controller 1200 may include a separate voltage supply source to provide the SET and RESET voltages. In the variation shown, the PCM controller 1200 is disclosed as a multiplexer that addresses the individual PCM mask elements 1210 , 1220 . Other variations may address the mask elements by column, by row, or may address the individual elements in non-multiplexed ways. In one variation, each mask element may have a separate signal pathway between it and a PCM controller. In another variation, shown in FIG. 1 d , the percentage of light transmitted through each pixel 1220 , 1230 of the PCM mask 1200 can be adjusted by controlling 1920 a laser power. In one variation, a CW laser 1900 crystallizes the material while a pulsed laser 1910 re-amorphizes it. In the variation shown, a PCM controller 1920 may be equipped with or connected to two different laser sources 1900 , 1910 . A first laser source may be a continuous wave (CW) laser 1900 whereas a second laser source 1910 may be a pulsed laser. In other variations, the PCM controller 1920 may be equipped with or connected to a single laser such as a femtosecond laser. In some variations, reversible switching in PCM can be accomplished, in some variations, by crystallizing with a laser in CW mode and then re-amorphizing with a 40 ns pulse laser at 16 mW. Other variations may use different types or intensities of lasers to SET and RESET the PCM. In some variations using PCM GST (Ge 2 Sb 2 Te 5 ) films, for example, for optical excitation, the energy density required to SET and RESET are: SET ˜24 mJ/cm2 and RESET ˜50 mJ/cm2. Molecular dynamics indicate quenching GST at dT/dt=−15 K/ps produces crystalline/amorphous phase transitions. In some optically switched variations of a coded PCM mask, the mask may be equipped with multiple waveguides or optical fibers feeding each individual pixel to change their properties at adjustable laser power levels. In some variations, the elements of a PCM coded mask may be smaller than the individual pixels in an FPA (focal plane array) covered by the mask. In some cases, a “superpixel” made up of smaller individual PCM coded mask elements may be coded onto one pixel of an FPA or other photodetector. In some variations, a single “pixel” of a PCM coded mask may be 10 microns or smaller. In some variations, the size of the “superpixel” may not necessarily match the pixel size of an underlying detector pixel. In some variations, the “superpixels” may be 2-dimensional arrays of PCM elements. The sizes of such arrays may match those of underlying detector pixels or may have larger or smaller sizes depending on an intended use or desired effect(s) of the PCM coded mask. Such a variation is shown in FIG. 2 a. In the variation shown, a PCM coded mask may be made up of multiple individually controllable PCM elements 2100 , 220 . Such PCM elements may be aggregated into “superpixels” 2000 . In some variations, such PCM coded mask superpixels 2000 may be equipped with a particular pattern that establishes a transmission pattern within the superpixel 2000 . In some variations, such a pattern may be repeated in some or all of the superpixels 2000 , 2300 . In some variations, different patterns may be applied to different superpixels 2400 in the PCM coded mask. In some variations, a superpixel in such a PCM coded mask may be controlled by a PCM controller (not shown) by setting a particular predetermine or otherwise preconfigured pattern onto the superpixel. In some such variations, the PCM controller and/or the superpixel(s) of the PCM coded mask may be equipped with one or more preconfigured or otherwise predetermined mask patterns that may be triggered by a particular signal or signal set transmitted from the PCM controller to a superpixel. In other variations, the PCM controller may address each PCM pixel element 2100 , 2200 individually. In further variations, the PCM controller may optionally address a PCM superpixel 2000 to establish a particular pattern in the superpixel 2000 or address individual PCM coded mask elements 2100 , 2200 to establish a particular refractive index or transmission state of that element. In one particular variation, a coded PCM mask element may be an individually addressable square element measuring 10 microns on a side. In some variations, such individually addressable elements may be aggregated into 16×16 superpixels that each cover one detector pixel of an FPA. In some variations, the coded PCM mask may include a 512×512 array of such 16×16 superpixels. In further variations, each superpixel in such an array may be equipped or otherwise configured with a particular masking pattern. In some variations, a superpixel 2000 may correspond to less than one pixel of an FPA. In some such variations, a group of superpixels may correspond to one or more pixels of an FPA. In other variations, a superpixel may correspond to more than one pixel of an FPA and/or have a shape or arrangement that does not overlap directly with an FPA pixel. For example, an FPA having a 30-micron pixel pitch may be covered by a coded PCM mask equipped with superpixels measuring 20 microns by 40 microns. In other variations, the superpixels may not all be the same shape. In some variations, the superpixels may not be square or rectangular. In some variations, the superpixels may have irregular shapes, such as L-shapes. Such variations are depicted in FIG. 2 b. In one variation, irregularly-shaped coded PCM mask superpixels 2900 , 2920 may be configured to fit together to form a rectangular shape that may be associated with a size of one or more underlying pixels. In some variations, such superpixels 2900 , 2920 may have different PCM masks. Such different masks may complement each-other or may be individually determined. In other variations, such superpixels 2950 , 2940 may have the same masks. In some variations, the PCM mask superpixels may be asymmetrically shaped 2960 , 2930 and may or may not be configured to form regular shapes such as squares, rectangles, triangles, or other polyhedrons. In such variations, the mask of each superpixel 2960 , 2930 may be individually established or separately controlled. In further variations, the PCM mask superpixels may be irregular shapes such as “cross” type shapes 2970 , 2910 , step-sided pyramids, t-shapes, s-shapes, or other shape variations. In some variations, such superpixels 2910 , 2970 may be shaped differently from each-other. In some variations, such superpixels 2910 , 2970 may have different mask patterns. Although discussed so far with respect to only two states (transmission/absorption, or on/off), some PCM mask variations also allow for graded/scaled masking instead of just switching mask elements/pixels into “on” and “off” states. In some variations large refractive index changes (delta n ˜2.4) can be achieved. In some variations, refractive index can be tailored from n˜3.8 in the amorphous to n˜6.2 in the hexagonal crystalline via meta-stable face centered cubic transition of the material structure. FIG. 3 a depicts such a range of refractive indexes for PCM GST in amorphous and crystalline states. The graph in FIG. 3 a shows the refractive index (n) and extinction coefficient (k) dispersion of Ge 2 Sb 2 Te 5 at the two extremes (amorphous and hexagonal crystalline phases). The extinction coefficient is related to the absorption. The index is shown by the solid line and the extinction coefficient by the dotted lines. As can be seen in the diagram, the refractive index of the PCM may vary based on a desired wavelength or wavelength range. In the variation shown, an index of refraction is depicted for near infra red (NIR) and mid-wave infra red (MWIR) imaging. As is shown in the diagram, for imaging wavelengths from approximately 1 to 5 microns, the amorphous PCM has an extinction coefficient of zero, making it essentially transparent to IR radiation. By contrast, the crystalline PCM has an extinction coefficient greater than zero, making it essentially opaque (or lossy) to IR radiation. Such variations may be realized using materials such as GST (Ge 2 Sb 2 Te 5 ) or other materials on the Ge—Sb—Te system or other PCM compositions Using a PCM coded mask as described herein for compressive sensing enables the optical design to be greatly simplified because there is no mechanical actuation of reflective elements and therefore a much simpler optical design. Furthermore, because the solution discussed herein operates in transmission (as compared to reflective designs using DMA) allowing for a simpler optical configuration; it does not require mechanical actuation (on/off states can be achieved by a phase transition from amorphous to crystalline state and design architecture) and can be adapted to the encoding scheme at the same spatial and/or temporal rate as the desired image/video reconstruction (it can be reconfigured/switched at nanosecond speeds using an external laser or voltage stimuli). This is so because switching times can be controlled by changing/optimizing the film structure in which the PCM layer is deposited. FIG. 3 b shows a chart indicating changes in reflectivity of an example of a PCM film stack using GST based on changes to an underlying layer of ZnS—SiO 2 . As can be seen from the chart, an initially crystallized PCM region 300 may have a reflectivity normalized to 1. When amorphized by either an appropriate voltage or laser stimulus 310 , the reflectivity may drop to approximately 0.8, with thicker layers of ZnS—SiO 2 being associated with a higher reflectivity. Subsequently, when re-crystallized 330 , a PCM layer disposed on a thicker region of ZnS—SiO 2 recovers its reflectivity more quickly. In cases where the ZnS—SiO 2 is less than a certain thickness 320 , a PCM film stack may have some difficulty in recovering an initial reflectivity. In some cases, even after a significant time period (160 nsec or more), reflectivity may not be recovered. As can be understood from the diagram in FIG. 3 b , there is flexibility in the design of a PCM coded mask architecture that can be used to optimize or otherwise configure the device properties. Although the example above depicts a particular film stack configuration using GST over ZnS—SiO 2 , other materials and material combinations may be used. Similarly, although the example shown varies the thickness of the ZnS—SiO 2 to change the film stack properties, the composition of that layer (and/or other layers) and the thicknesses of other layers (such as, for instance, the GST layer) may also be altered to change the properties of the PCM film stack. As can be seen in the diagram of FIG. 3 b , switching time for changing from crystallized to amorphous and back to crystallized states can be realized in as little as ˜15 nanoseconds. In some cases, amorphization may be realized in less than one nanosecond and crystallization may be realized in under 15 nanoseconds. Such fast switching time enables the creation and use of PCM coded masks for that can be reconfigured at fast switching times (few nsec as compared to millisecond for the DMA), providing the ability for better image reconstruction and quality, especially when the target object is moving. In the variation shown, the 15 nm, 25 nm, and 50 nm thicknesses of ZnS—SiO 2 require fluencies of 52 mJ/cm 2 , 47 mJ/cm 2 , and 31 mJ/cm 2 , respectively, to achieve the transition from crystallized to amorphous states. Such fluence levels may be realized with nanosecond or femtosecond lasers. Also, in the variation shown, the third layer of the PCM material stack is Aluminum. In other variations, this layer may be omitted or replaced with materials such as doped silicon or indium tin oxide (ITO). Material composition of the underlying layers of a PCM material stack may be determined based on a desired wavelength or waveband of electro-optical radiation to be detected by an underlying photodetector. Doped silicon and ITO, for example, are transparent to infra-red radiation. Only exemplary embodiments of the present invention are shown and described in the present disclosure. It is to be understood that the present invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein. Such variations are not to be regarded as departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims:

Variations of the techniques, systems, devices, and methods discussed herein pertain to a pixel-level mask for a photo-detector. Such a mask may have a layer of reconfigurable phase-change material (PCM) configured to vary between a first refractive index and a second refractive index. Such a PCM layer may be divided into individual pixel areas such that each individual pixel area may be set to have the first refractive index or the second refractive index. The PCM layer may be disposed on a photo-detector such that incident radiation detected by the photo-detector must pass through the PCM layer in order to be detected. The mask may also include or otherwise be operably connected to a PCM controller that can control the refractive index of an individual pixel area or a group of pixel areas aggregated into a superpixel.

FIELD OF THE INVENTION [0001] The present invention relates to printing inks for the intaglio printing process, also referred to as engraved steel die printing process. In particular, oxidatively curing inks comprising a combination of fusible wax and a UV curing binder component are disclosed. These inks can be printed on a standard printing press and allow to significantly reduce or eliminate the undesired set-off which can occur after printing and stacking the printed sheets. Using the inks of the present invention results in less set-off contaminated printed sheets, allowing for a higher pile-stacking of the printed good, for the use of increased engraving depths, of a more challenging intaglio design, and for the printing on less porous substrates, while enabling the printing on a standard printing press, and offering the possibility of using a lower printing plate temperature. BACKGROUND OF THE INVENTION [0002] In the engraved steel die printing process, hereafter called intaglio printing process, a rotating engraved steel cylinder, carrying a pattern or image to be printed, and heated to a temperature of the order of 80° C., is supplied with ink by one or more template inking cylinders. Subsequent to the inking, any excess of ink on the plain surface of the printing cylinder is wiped off by a rotating wiping cylinder. The remaining ink in the engraving of the printing cylinder is transferred under pressure onto the substrate to be printed, which may be a paper or plastic material in sheet form, while the wiping cylinder is cleaned by a wiping solution. Other wiping techniques can also be used, such as paper wiping or tissue wiping (“calico”). [0003] One of the distinguishing features of the intaglio printing process is that the film thickness of the ink transferred to the substrate can be varied from a few micrometers to several tens of micrometers by a correspondingly shaped printing plate. This ability to vary the film thickness is a most desirable feature of the intaglio printing process and can be used to produce embossing effects, i.e. to confer tactility to the printed document, as well as to produce shade variations using one and the same ink. [0004] The pronounced relief of the intaglio printing accentuates the problem of “set-off”, which is the transfer of ink from one printed sheet to the back side of the next following printed sheet in a stack, or to the back of the endless sheet in a web. The factors influencing the “set-off” are determined by the printing ink formulation, the engraving depth and evenness, the printing conditions, the printing substrate, the number of stacked sheets per pile, the time between printing and handling of the piles and the way how the printed piles of paper are handled after printing. [0005] The “set-off” caused by the residual tackiness of the printed ink, which adheres to the substrate surface of the back of the next sheet, is aggravated when pressure is applied to a pile of stacked printed sheets. Depending on its extent, “set-off” can irreversibly spoil the printed product affected by it. A classical method to avoid losses of printed good due to “set-off” is to interleave separation sheets between all printed sheets; this leads however to a slowing down of the printing process and also to a more expensive printing. [0006] The problem of reducing set-off in oxidatively curing inks has been addressed in the art in several ways: [0007] by using high molecular weight oxidatively curable binders, [0008] by solvents with relatively low boiling point which would partially evaporate on the printing plate, [0009] by waxes, forming a protective layer on the ink film, [0010] by a high filler to binder ratio which would reduce the residual tackiness of the ink, and [0011] by efficient metal catalysts which ensure the rapid through-curing of the printed ink film. [0012] WO 03/066759 (and the related JP 2002-38065 and JP 01-289878) disclose a dual-curing ink matrix, comprising a UV curable material as the principal component (around 40 wt-%), together with an oxidatively curing alkyd resin as a secondary component (around 5 wt-%), a photoinitiator, and an oxidative polymerization catalyst. The disclosed ink composition does not comprise fusible wax. [0013] This ink is subjected to UV curing immediately following the printing operation, whereupon it instantly dries, at least at the surface, with the consequence that set-off cannot occur. A slower, in-depth post-curing takes place during the following hours and days according to an oxypolymerization mechanism, allowing for a good adhesion of the ink to the substrate even in the presence of UV-opaque pigments or fillers. [0014] The ink according to WO 03/066759 requires particular, e.g. EPDM rubber equipped, printing presses, designed for the printing of UV curing inks; the ink cannot be printed on an Intaglio printing press equipped for printing standard oxypolymerization curing, greasy inks. [0015] WO 01/38445 A1 addressed the “set-off” of intaglio printing inks on polymer substrates. The binder of the therein disclosed intaglio printing ink includes an auto-oxidizable polyester resin having fatty acid residues, and a wax dispersion having a glass transition temperature below the maximum temperature achieved during the printing process. The disclosed printing ink further includes solvents and pigments and can be cured under UV radiation. This printing ink contains no acrylates at all. [0016] The majority of intaglio printing inks used today are still alkyd based, greasy inks, which cure according to a purely oxidative drying mechanism. They traditionally contain hydrocarbon solvents. In consequence, the printing machines in the majority of printing works are equipped with inking systems, printing blankets and wiping cylinders which are specifically designed to resist to the alkyd- and hydrocarbon solvent-based chemistry of these traditional intaglio printing inks, but which, in turn, do not resist to the more polar UV-ink chemistry. [0017] Oxidatively drying alkyds, as compared to UV-curing inks have, however the shortcomings of an inherently slow drying, which results in a lower production rate, of the need to use environment-unfriendly organic solvents (VOC=volatile organic compounds), and of the intrinsic proneness of these inks to produce “set-off” as a consequence of their slow drying. Their main advantage, in turn, is a good in-depth curing provided by the oxidative drying mechanism, resulting in good physical and chemical resistances of the printed and dried product. The printing equipment adapted to print them is furthermore already in place at every printing work. [0018] UV-curing intaglio printing inks, on the other hand, have the advantage of a fast or almost immediate surface drying, eliminating waiting times and allowing for a high production rate. The presence, in the ink formulation, of volatile organic compounds can be avoided, and set-off does not occur due to the instant-drying. [0019] The shortcomings of UV-inks, in turn, are that in-depth curing remains a challenge, in particular in case of a high pigment loading in the ink and/or the presence of pigments which are opaque or which have a high absorbance in the UV spectrum. UV-curable intaglio printing inks are furthermore significantly more expensive than traditional alkyd based inks, and, even more important, the printing equipment needs a major change of all components which come into contact with the UV-curable printing ink, in particular the rollers made of rubber or other polymer materials, which must be redesigned to resist the different chemistry of the UV-inks. [0020] The chemical composition of UV-curing intaglio printing inks is noteworthy entirely different from that of alkyd-/hydrocarbon solvent based intaglio printing inks. When UV-curable intaglio printing inks come in contact with the alkyd-/hydrocarbon solvent-specific rubber components of the inking system, the printing blankets and the wiping cylinders of the printing machine, they can cause a swelling or shrinking of the rubber, which in turn alters the geometry of the rollers and blankets. This results in a low printing quality, as well as in a reduced roller lifetime, altogether increasing the printing and maintenance cost. [0021] In practice, to allow for the printing of UV-curing intaglio inks, the rollers of the printing machine must be made of a special material or protected by a highly resistant compound such as non-polar EPDM rubber (ethylene propylene diene monomer rubber). Thus an additional cost arises for the printer if he changes from traditional alkyd-based intaglio inks to energy-curable intaglio inks, which is caused on the one hand by the more expensive energy-curable (UV-curable) intaglio printing ink itself, and on the other hand by the expensive upgrade of the printing equipment to become UV-ink compliant. A further disadvantage results for the printer who needs to print in both technologies, because each time he changes the type of printing ink (UV-curable or oxidatively curable, respectively), all corresponding parts of the printing machine must be changed accordingly in a time-consuming operation. [0022] It would thus be highly desirable to have available an ink which combines the favorable set-off properties of the UV intaglio inks with the good in-depth curing of the alkyd intaglio inks, which results in high physical and chemical resistances of the printed ink on the document, and which is compatible with (i.e. printable without change on) the existing intaglio printing equipment in place at the printers' premises. [0023] It is the object of the present invention to provide an intaglio printing ink which has very good set-off resistance and in-depth curing values, and which can be printed on the conventional intaglio printing equipment designed for oxidatively curing inks. SUMMARY OF THE INVENTION [0024] The present invention is related to an intaglio printing ink composition comprising as a principal component an oxidatively curable material, such as an alkyd resin or a modified alkyd resin, and, as an auxiliary component, a combination of a UV curable material and of a fusible wax, characterized in that said composition, after a thermal cycling from 25° C. to 80° C., to 25° C., and after irradiation with a curing dose of UV light, shows an increase in its complex dynamic modulus of at least 50%, preferably at least 100%. [0025] The thermal cycling used in the present invention corresponds to the ink's typical variation of temperature during the conventional intaglio printing process. The temperature of the intaglio plate during the printing operation is traditionally chosen to be around 80° C., and the inks are formulated in consequence as to the melting temperature range of their fusible wax components. The inks of the present invention, having a particular mechanism to increase viscosity after printing, allow for more freedom in choosing the printing plate temperature. In particular, inks containing temperature-sensitive components can be formulated so as to be printable at a lower temperature, such as 60° C. or even 50° C., whilst still obtaining a good set-off resistance of the freshly printed sheets. [0026] According to the present invention, a curing dose of UV light means a dose which would dry-cure a corresponding UV-ink. [0027] Said increase in complex dynamic modulus means that the printed ink is gelling following the UV-irradiation, and in consequence loses much of its initial tackiness. The dynamic modulus is a measure for the ink's rheologic behavior; an increase of this modulus by 50% is highly significant with respect to set-off resistance. [0028] In particular, the ink according to the present invention has, as a principal component, an oxidative curing material in an amount between 20 and 50 wt-% of the total printing ink, which provides it with good in-depth drying properties, and, as an auxiliary component, a combination of fusible wax in amounts up to 10 wt.-%, preferably between 2 and 5 wt-%, and a UV curing material in amounts between 2 and 15 wt-%. [0029] It was found that the said combination of fusible wax and the UV curing component allowed the printed ink to be surface-stabilized through a short UV irradiation following the printing operation, so as to avoid set-off, while still being printable on standard printing equipment at full printing speed, but allowing for a higher stacking of the printed goods. The good in-depth curing and the physical and chemical resistances of traditional oxidatively curing intaglio inks are maintained. [0030] The ink of the invention has chemical properties which are close to the ones of traditional intaglio inks, and it can, for this reason, be printed on a conventional intaglio printing press, without the need for changing the rubber parts on the printing machine which come into contact with the printing ink. The only requirement for the printer is the additional presence of a UV irradiating unit on an otherwise standard intaglio printing press. [0031] The intaglio printing ink of the present invention is principally an oxidatively curing intaglio ink, which in addition to wax, comprises a UV-curable component, preferably in an amount of 2 to 15 wt-%, more preferably of 4 to 8% by weight of the total printing ink composition. Through a UV exposure immediately after the printing operation, the printed ink surface is stabilized, so as to allow a stockpiling (stacking) of the printed sheets, without producing “set-off” even under particularly unfavorable conditions. Significantly higher stacks of printed goods can therefore be envisaged. [0032] The ink of the present invention is, however, not dry after the short UV irradiation following the printing operation. This is evidenced by the fact that, under strong pressure, the printed and UV-irradiated ink of the present invention nevertheless transfers to a second sheet of substrate, whereas a printed and UV-irradiated UV-curing ink does not. The surface and in-depth curing of the ink of the present invention takes place during the hours or days which follow the printing operation, through an oxypolymerization process under the influence of air oxygen, as known for traditional intaglio inks. [0033] The formulation of oxidatively curing inks is known to the skilled person. Such inks comprise an oxidatively curable material and an oxypolymerization catalyst (drier). Oxidatively curable materials, useful as the oxidatively curable component, can be of natural or synthetic origin. Typical oxidatively curing materials of natural origin are oligomers or polymers based on vegetable oils, such as linseed oil, tung oil, tall oil, as well as other drying oils known to skilled person. Typical oxidatively curing materials of synthetic origin are alkyd resins, such as can be obtained, as known to the skilled in the art, for example by the joint condensation (esterification) at 180° C. to 240° C. of [0034] one or more polycarboxylic acids, such as ortho-, iso-, or ter-phthalic acids, ortho-tetrahydrophthalic acid, fumaric acid, maleic acid, or a corresponding anhydride thereof; [0035] one or more polyhydric alcohols, such as glycol, trimethylolethane, pentaerythritol, sorbitol, etc.; and [0036] one or more unsaturated fatty acids, such as linseed oil, tung oil or tall oil fatty acids. [0037] Such oxidatively curable components are present in the ink according to the invention preferably in amounts of 20 to 50% by weight, most preferably of 30 to 45% by weight, of the total printing ink. [0038] The UV-curable material, useful as the UV-curable component, can be selected from the group of acrylate monomers, oligomers or polymers, such as amino acrylates, epoxy acrylates, polyester acrylates, urethane acrylates, self-photoinitiating oligomer acrylates, dendritic acrylates, as well as mixtures thereof. Preferred UV-curable components are acrylate oligomers and polymers. [0039] The intaglio printing ink of the present invention further comprises at least one siccativating agent, i.e. an oxypolymerization catalyst, which may be the salt of a long-chain fatty acid with a polyvalent metal cation, such as cobalt(2+), vanadyl(2+), manganese(2+), or cerium(3+). Salts of the said type are oil soluble and thus compatible with fatty alkyd based inks. The ink may further comprise soaps of calcium and/or zirconium and/or cerium as a co-siccativating agent to further improve the in-depth curing. The siccativating agent is usually present in amounts of up to 5% by weight, preferably of 1 to 3% by weight, of the total printing ink composition. [0040] The intaglio printing ink of the present invention further comprises at least one photoinitiator for initiating the polymerization reaction of the UV-curable components. The photoinitiator is usually present in amounts of up to 5% by weight, preferably of 1 to 3% by weight, of the total printing ink composition. Suitable photoinitiators are known to the skilled person and are e.g. of the acetophenone type, the benzophenone type, the α-aminoketone type, or, preferably, the phosphine oxide type. One suitable photoinitiator is Irgacure 819 from Ciba. [0041] The intaglio printing ink composition may further comprise photoinitiator stabilizers (UV stabilizer) in an amount of up to 3%, preferably of 0.5 to 3%, more preferably of 1.5% by weight of the total printing ink. [0042] The inventors further found out that the simultaneous presence of, on the one hand, fusible wax, which is known to reduce the “set-off” in traditional intaglio printing inks, and, on the other hand, UV-curable acrylates, resulted in a synergistic effect in preventing the “set-off” of the printed intaglio inks of the present invention to a dramatic and unexpected degree, if the inks are subjected to UV irradiation immediately after the printing operation. [0043] The intaglio printing ink of the present invention thus further comprises at least one fusible wax, such as a Montan wax based material, e.g. refined Montan wax, Montanic-acid, -amides, or -esters; modified or saponified Montan wax, or Carnauba wax, or other similar synthetic long chain ester wax or mixtures thereof. The fusible wax or waxes are comprised in the intaglio printing ink of the present invention in amounts of up to 10% by weight, preferably between 1 to 10%, more preferably between 1 to 5%, and even more preferably between 2 to 5% by weight of the total printing ink. [0044] Within the context of the present invention, fusible wax refers to a wax or a wax mixture having a melting point or a melting interval of the neat product in the range of between 50-120° C., preferably of between 55-100° C., more preferably of between 60-85° C. In the printing ink composition, the corresponding melting points or melting intervals of the wax are lowered due to the presence of other compounds. [0045] The intaglio printing ink composition may further comprise other components such as pigments for providing the color of the ink, fillers, emulsifiers, solvents, e.g. for the viscosity adjustment, as well as special additives and/or markers for security or forensic purposes. DETAILED DESCRIPTION OF THE INVENTION [0046] The intaglio printing ink composition of the present invention comprises at least one oxidatively curable principal component, preferably in amounts between 20 and 50 wt-% of the total ink composition, at least one UV-curable component, preferably in amounts between 2 and 15 wt-% of the total ink composition, at least one oxypolymerization drier, at least one photoinitiator, and at least one fusible wax, preferably in amounts between 1 to 10 wt-%, of the total ink composition. Optionally, pigments, fillers, additives and solvents, as well as a stabilizing agent for the UV-curing part, may be present. [0047] The oxidatively curable component can be selected from the group consisting of the alkyd resins and the modified alkyd resins of synthetic or natural origin, in particular phenol-, epoxy-, urethane-, silicone-, acryl- and vinyl-modified alkyd resins, neutralized acid alkyds, and siccativating vegetable oils. Typical oxidatively curing materials of synthetic origin are the alkyd resins obtained by esterification of a mixture of one or more polyhydric carboxylic acids or acid derivatives, such as anhydrides and/or their hydrogenated equivalents, and one or more unsaturated fatty acids of natural origin, with one or more polyols, such as ethylene glycol, glycerol, pentaerythritol etc. Examples for such alkyd resins are disclosed in EP 0 340 163 B1, the respective content thereof being incorporated herein by reference, in particular the examples II and III. [0048] The oxidatively curable component is present in amounts of 20 to 50% by weight, preferably of 25 to 40% by weight, and most preferably in an amount of 30 to 35% by weight of the total printing ink. [0049] The siccativating agent (drier), i.e. the oxypolymerization catalyst, is added to promote the in-depth curing of the alkyd under the influence of air oxygen. Said drier is typically based on transition metal salts which are soluble in the oil based printing ink medium. The ions of the chemical elements with numbers 23 to 29, as well as those of certain other chemical elements, are potentially useful in driers. Particularly preferred is a combination of cobalt and manganese carboxylates, or of cobalt, manganese and zirconium carboxylates, wherein the carboxylate is a long-chain carboxylic acid anion. A particularly preferred drier comprises cobalt(II) octoate, manganese(II) octoate, and zircon(IV) octoate in a hydrocarbon solvent. Other suitable driers have been disclosed in co-pending patent application EP07112020.8 of the same applicant. The drier is present in amounts of up to 5%, preferably 0.5 to 5 wt-%, and more preferably of 1 to 3 wt-% of the total printing ink. [0050] The UV-curable component is preferably an acrylate, a monomer or preferably an oligomer or polymer. Said acrylate may be selected from the group consisting of the amino acrylates, the epoxy acrylates, the polyester acrylates, the urethane acrylates, the self-photoinitiating oligomeric acrylates, the dendrimeric acrylates, and mixtures thereof. Examples of suitable UV-components are given in Table 1. [0000] TABLE 1 Resin Type Trade Name Supplier acrylate monomers TMPTA, HDDA, NPGDA, PETA, Cytec and many other products and many other from different suppliers suppliers amino acrylates Genomer 5275 Rahn Uvecryl P115 UCB epoxy acrylates Craynor 132 Sartomer Laromer LR 8765 BASF polyesters acrylates Ebecryl 450 Cytec urethanes acrylates Photomer 6618 Cognis Actilane 245 Akzo Ebecryl 2003 Cytec Ebecryl 220 Cytec dendritic acrylates BDE-1029 IGM Resins BDE 1025 IGM Resins Self-photoinitiating Drewrad 1122 Ashland oligomer acrylate Acrylate oligomer Ebecryl 600 Cytec [0051] The UV-curable component is preferably present in an amount of 2 to 15% by weight, more preferably of 4 to 8% by weight, most preferably of 5 to 7% by weight, of the total printing ink. [0052] The intaglio printing ink of the present invention further comprises at least one photoinitiator. Said photoinitiator is typically present in amounts of up to 5% by weight, preferably of 0.5 to 5% by weight, more preferably in amounts of 1 to 3% by weight, and most preferably of 1 to 2% by weight of the total printing ink. [0053] Suitable photoinitiators can be chosen from the group consisting of the α-aminoketones (e.g. Irgacure 369, Irgacure 907), the α-hydroxyketones (e.g. Irgacure 2959), the phosphine oxides (e.g Irgacure 819), the thioxanthones (e.g. ITX), the oligomeric thioxanthones (e.g. Genopol TX-1), the oligomeric amino benzoates (Genopol AB-1), the oligomeric benzophenones (e.g. Genopol BP-1). These types of photoinitiators are known to the skilled person; they generate free radicals upon UV irradiation, initiating a radical polymerization reaction of the UV curable component, such as the acrylate. [0054] Fusible waxes suitable to carry out the present invention may be chosen from the group of refined Montan wax, Montanic-acid, -amide, -ester; modified or saponified Montan wax, Carnauba wax, long chain ester wax, and mixtures of these. Examples of suitable waxes are given in Table 2. The melting point or melting range of the fusible wax suitable to carry out the invention is between 50 to 120° C., preferably between 55 to 100° C., more preferably between 60 to 85° C. [0000] TABLE 2 Type of Wax Trade Name Melting Point* Refined Montan wax Licowax U ~86° C. Montanic acids Licowax S ~82° C. Licowax SW ~83° C. Licowax LP ~83° C. Licowax UL ~83° C. Licowax NC ~84° C. Esterified Montanic Licowax E ~82° C. acids Licowax F ~79° C. Licowax KP ~87° C. Licowax KPS ~82° C. Esterified, partly Licowax O ~100° C.  saponified Montanic Licowax OP ~100° C.  acids Licowax OM ~89° C. Montan based Printwax MM8015 ~95° C. Montan/Carnauba Printwax MX6815 ~90° C. The indicated melting points are those given by the suppliers for the neat wax. Licowax is supplied by CLARIANT Printwax is supplied by DEUREX GmbH, Töglitz [0055] Other type of waxes, such as paraffin, polypropylene, polyethylene amide or PFT waxes and the like, can be further comprised in the printing ink composition of the present invention without disturbing the synergistic effect on the set-off displayed by the simultaneous presence of fusible wax and acrylate under UV irradiation immediately after printing. They may be used for adjusting other properties of the intaglio printing ink, such as rub resistance or rheological behavior, as known to the skilled person. [0056] According to a further aspect of the invention, a photoinitiator-stabilizer (UV-stabilizer) may also be comprised in the ink. Such photoinitiator-stabilizers are known to the skilled person. Useful stabilizers are e.g. Florstab UV-1, supplied by Kromachem, and Genorad 16, supplied by Rahn. [0057] Said photoinitiator-stabilizer is comprised in the ink in an amount of up to 3%, preferably of 0.5 to 3%, more preferably in an amount of 1 to 2%, most preferably in an amount of 1.5% by weight of the total printing ink. [0058] The presence of the UV-stabilizer serves to avoid a premature polymerization during the preparation or during the handling of the ink prior to use on the printing press as well as prior to the radiation-curing step. Furthermore, the UV-stabilizer provides a longer shelf live to the printing ink. [0059] The intaglio ink of the present invention further may comprise pigments and fillers, as well as mineral solvents. The pigment content of intaglio printing ink composition is generally in the range of 3 to 30%, more usually in the range of 5 to 15%, by weight of the total printing ink. Suitable pigments for use in intaglio inks are known to the skilled person. [0060] According to a further aspect of the invention, the filler content of the printing ink composition may be in the range of 5 to 50%, by weight of the total printing ink. The filler can be e.g. of natural origin, such as chalk, china clay, exfoliated mica, or talcum, or synthetically prepared, such as precipitated calcium carbonates, barium sulfate, bentonite, aerosil, titanium dioxide, or also mixtures of some of these. [0061] Suitable mineral solvents for embodying the present inventions are linear or branched organic hydrocarbon solvents with chain lengths of C 10 to C 15 and having a boiling point between 180 and 290° C., such as PKW 1/3, PKW 4/7 AF, PKWF 6/9 neu or PKW 6/9 AF (e.g. from Halterman), as well as fatty acid esters. Oxygenated or polar solvents, such as glycol ethers, may be added as co-solvents. [0062] The viscosity of the ink is adjusted with mineral solvent and additives, e.g. Aerosil, to about 1 to 40 Pa·s, preferably about 3 to 25 Pa·s, more preferably to about 6 to 15 Pa·s, measured on a cone-plate geometry at 1000 s −1 and 40° C. [0063] The intaglio printing ink of the present invention is preferably prepared according to the following process, comprising the steps of: [0000] a) grinding together, preferably on a three-roll mill, at least one oxypolymerization-curable component, such as an alkyd resin, at least one UV-curable component, such as an acrylate, at least one fusible wax, and optional fillers and solvents, to obtain a homogeneous dispersion; b) grinding together, preferably on three-roll mill, at least one oxypolymerization-curable component, such as an alkyd resin, at least one pigment, and optional fillers and solvents to obtain a homogeneous dispersion; c) mixing and grinding together the dispersion of step a), the dispersion of step b), an oxidative drier (siccativating agent), a photoinitiator and an optional photoinitiator stabilizer, to obtain the printing ink of the invention. [0064] A first oxypolymerization-curable component, such as an alkyd resin, may be used in step a) and a second, different oxypolymerization-curable component, such as an alkyd resin, in step b), in order to assure best compatibility with the UV-curable acrylate and with the pigment, respectively. [0065] Care must be taken during the mixing together of the printing ink components that the temperature does not exceed 50° C., because the UV curable component, such as an acrylate component, may undergo a premature polymerization reaction, making the ink useless for further application. For this reason, the mixing of the ink components is preferably carried out on an open three roll mill system rather than in a ball mill mixing equipment. [0066] As will be appreciated by the skilled person, the production of the ink according to the present invention is not restricted to the indicated process; however, using the indicated process prevents any uncontrolled heating of the printing ink and therefore offers some guarantees against the premature and uncontrolled polymerization of the acrylic components during the ink manufacturing step. [0067] The inventors have found that there is an inherent correlation between the “set-off” shown by an intaglio printing ink and its internal structural properties, sometimes also referred to as the cohesion force or cohesive strength, which can be considered as the force which is necessary to disrupt an applied coating layer (film splitting). [0068] The complex dynamic modulus G* is a measure for the said cohesive strength of the ink, and is defined as: [0000] G*=G′+iG″ [0069] wherein G′ is the elastic modulus (also called storage modulus), [0070] and G″ is the plastic or viscous modulus (also called loss modulus). [0071] The inventors surprisingly found that the simultaneous presence of fusible wax and a moderate amount of UV-curable acrylate oligomer significantly increased G* after thermal cycling, followed by exposure of the ink to UV light. In other words, the internal cohesion of the ink increased, which turned out to strongly decrease the “set-off” tendency of the ink: [0072] Due to the simultaneous presence of the fusible wax and the UV curable component, after irradiation of the printed intaglio ink of the present invention by UV light following the printing operation, involving a thermal cycling of the ink, no “set-off” was observed any more, as is the case for UV-irradiated UV-curing inks. In contrast to UV-curing inks, the ink of the present invention is, however, not “dry” after the UV-irradiation, and only dries through oxypolymerization during the following hours and days. The present ink remains, as to its principal parts, an oxidatively curing intaglio ink having good in-depth drying and long-term mechanical and chemical resistances, which can be printed using standard printing equipment with rubber parts designed for printing greasy alkyd inks, given that a UV-irradiation unit is present on the printing press. [0073] The UV-radiation may hereby be generated by conventional mercury UV-lamps, electron-less bulb UV-lamps, pulsed UV-lamps, UV-light-emitting-diodes (UV-LED's) and the like, capable of emitting UV-A, UV-B, and/or UV-C radiation. [0074] A method of intaglio printing, using an intaglio printing ink according to the present invention, comprises thus the steps of a) intaglio-printing the ink onto a substrate, hereby cycling the ink's temperature from room temperature to printing plate temperature and back to room temperature; b) subjecting the printed document to UV-radiation following the printing operation; and c) storing the printed document for several days, to allow for oxidative curing of the printed ink. [0075] According to the present invention, room temperature is meant to be 25° C. The printing plate temperature is typically 80° C., as described above, but with specific inks can be as low as 50° C. [0076] The features of the disclosed intaglio ink result in a neat advantage for the printer, who can run his standard intaglio press with higher efficiency and versatility. These improvements are reached through the synergistic effect onto the “set-off” tendency of the printed ink of small amounts of both, fusible wax and UV-curable acrylates. [0077] The present invention will now be described in more detail with reference to non-limiting examples and drawings. [0078] FIG. 1 shows a plot of the experimentally determined complex dynamic modulus (G*, Pa), measured before and after heat-cycling (25° C.-80° C.-25° C.) of the ink, against the experimentally determined set-off resistance value (determined according to the method given below on an empirical scale going from 1 (bad) to 6 (excellent)) for four different intaglio inks of the prior art, each without and with a fusible wax component. [0079] FIG. 2 a - c illustrate the synergistic effect of the simultaneous presence of fusible wax and UV-curable acrylate in an intaglio ink to prevent set-off after printing for the following example 1 and comparative examples 1 to 3. In detail: [0080] FIG. 2 a shows a plot of the experimentally determined set-off value versus the complex dynamic modulus G*=G′+iG″ [Pa, as an absolute value] [0081] FIG. 2 b shows a plot of the set-off value versus the elastic component G′ (real part of G*; also called the storage modulus) [0082] FIG. 2 c shows a plot of the set-off value versus the plastic or viscous component G″ (imaginary part of G*, also called the loss modulus). [0083] FIG. 3 shows the intaglio-printed test image used to assess the set-off and drying properties of the inks (shown in FIG. 4 a - d ). [0084] FIG. 4 a - d illustrate the cooperative effect of a UV-curable component and a fusible wax onto the set-off properties of the inks, as exemplified with example 1 and comparative example 1. EXAMPLE 1 Ink of the Present Invention (“Modified 30”) [0085] An intaglio ink according to the present invention was prepared as follows (the amounts are given as wt.-% with respect to the final ink composition): [0086] A first part of the ink was prepared by combining the following components, and grinding them on a conventional three-roll mill (Bühler SDY-200), as known to the skilled in the art, so as to form a homogenous dispersion: [0000] Part I Component Amount (wt.-%) Neutralized acid alkyd 11 (prepared as disclosed in EP 0 340 163 B1, p. 9, l. 45-51) Acrylated oligomer 7 (Ebecryl 600, of Cytec) Surfactant 3 (sodium dodecylbenzene-sulfonate) Mineral solvent 4 (PKWF 6/9 neu, of Haltermann) Talcum 2 Polyethylene wax 2 (Ceridust 9615A, of Clariant) Fusible wax 5 (Carnauba wax) Mineral filler 24.5 (Sturcal L, of Specialty Minerals) Total 58.5 [0087] A second part of the ink was prepared by combining the following components, and grinding them on a three-roll mill, so as to form of a homogenous dispersion: [0000] Part II Component Amount (wt.-%) Modified alkyd 12.5 (Urotuföl SB650 MO 60, of Reichhold Chemie, or the alkyd resin of part I) Phenolic modified rosin based varnish 5.5 (solution of Sylvaprint MP6364 of Arizona (45%) in PKWF 4/7 (15%) and linseed oil (40%)) Mineral solvent 1 (PKWF 6/9 neu, of Haltermann) PB 15:3 blue pigment 7 (Irgalite blue GLO, of CIBA) Mineral filler 9.5 (Sturcal L, of Specialty Minerals) Total 35.5 [0088] The final ink was prepared by combining on a three-roll mill the above parts I and II with the following additional components: [0000] Final ink Component Amount (wt.-%) Part I 58.5 Part II 35.5 Photoinitiator 2 (Irgacure 819, of Ciba) UV stabilizer 1.5 (Florstab 1, of Floridienne) Metal drier 2.5 (blend of octa-soligen cobalt (12 parts) and Octa-soligen manganese (8 parts), of Borchers) Total 100 [0089] The viscosity of the final ink was adjusted with mineral solvent and additives, e.g. Aerosil, to about 1 to 40 Pa·s, preferably about 3 to 25 Pa·s, more preferably to about 6 to 15 Pa·s, measured on a cone-plate geometry at 1000 s −1 and 40° C. COMPARATIVE EXAMPLE 1 “Modified 30 without Wax” [0090] The ink was prepared as described above in example 1, except that in part I no fusible wax was added. Instead, the amount of the mineral filler (Sturcal L, of Specialty Minerals) was raised to 29.5 wt.-% (based on the final ink composition) in order to compensate for the lack of fusible wax. COMPARATIVE EXAMPLE 2 “Standard” [0091] The ink was prepared as descried in example 1, except that no UV-curable resin was present. [0092] A first part of the ink was prepared by combining the following components, and grinding them on a three-roll mill, so as to form a homogenous dispersion (the amounts are given as wt.-% with respect to the final ink composition): [0000] Part I Component Amount (wt.-%) Neutralized acid alkyd 18 (prepared as disclosed in EP 0 340 163 B1, p. 9, l. 45-51) Acrylated oligomer — (Ebecryl 600, of Cytec) Surfactant 3 (sodium dodecylbenzene-sulfonate) Mineral solvent 4 (PKWF 6/9 neu, of Haltermann) Talcum 2 Polyethylene wax 2 (Ceridust 9615A, of Clariant) Fusible wax 5 (Carnauba wax) Mineral filler 24.5 (Sturcal L, of Specialty Minerals) Total 58.5 [0093] A second part of the ink was prepared by combining the following components, and grinding them on a three-roll mill, so as to form a homogenous dispersion (the amount of the alkyd resin and the filler in part II was increased to compensate for the lack of UV-photoinitiator and UV-stabilizer in the final ink): [0000] Part II Component Amount (wt.-%) Modified alkyd 14 (Urotuföl SB650 MO 60, of Reichhold Chemie, or the alkyd resin of part I) Phenolic modified rosin based varnish 5.5 (solution of Sylvaprint MP6364 of Arizona (45%) in PKWF 4/7 (15%) and linseed oil (40%)) Mineral solvent 1 (PKWF 6/9 neu, of Haltermann) PB 15:3 blue pigment 7 (Irgalite blue GLO, of CIBA) Mineral filler 11.5 (Sturcal L, of Specialty Minerals) Total 39 [0094] The final ink was prepared by combining on a three-roll mill the above parts I and II with the following additional components: [0000] Final ink Component Amount (wt.-%) Part I 58.5 Part II 39 Photoinitiator — (Irgacure 819, of Ciba) UV stabilizer — (Florstab 1, of Floridienne) Metal drier 2.5 (blend of octa-soligen cobalt (12 parts) and Octa-soligen manganese (8 parts), of Borchers) Total 100 [0095] The viscosity of the final ink was adjusted with mineral solvent and additives, e.g. Aerosil, to about 1 to 40 Pa·s, preferably about 3 to 25 Pa·s, more preferably to about 6 to 15 Pa·s, measured on a cone-plate geometry at 1000 s −1 and 40° C. COMPARATIVE EXAMPLE 3 “Standard without Wax” [0096] The ink was prepared as described above in comparative example 2, except that in part I no fusible wax was added. Instead, the amount of the Mineral filler (Sturcal L, of Specialty Minerals) was raised to 29.5 wt.-% (based on the final ink composition) in order to compensate for the lack of fusible wax. Measurements [0097] The set-off resistance values were determined as follows: 10 intaglio prints were made on banknote paper (175×145 mm) on a trial press with the exemplary inks, using a standard, heated intaglio plate having fine, medium and deep engravings (up to 120 μm). The 10 printed sheets were immediately stacked on top of each other, with 10 blank interleaving sheets between them, and weight of 2 kg was placed on the stack. After 24 hours, the stack was separated, and the set-off to the interleaving sheets was evaluated on a statistical basis, by comparing each interleaving sheet with a scale of reference set-off sheets. A value between 1 (bad) and 6 (excellent) was attributed to each sheet, and the mean value of the 10 sheets was taken as being representative of the set-off of the ink in question. [0098] The reference set-off sheets represent a standard intaglio image ( FIG. 3 ) in a linear series of photometric graduations, going from perfect copy (set-off value 1) to no copy at all (set-off value 6). Set-off values for practicable inks must be close to 6. [0099] The complex dynamic modulus G* (in Pa) of the inks in question was determined on a AR1000 rheometer from TA Instruments in oscillating mode at 25° C.; cone 4 degree, 2 cm diameter, frequency 1 Hz. [0100] In FIG. 1 , a plot of the experimentally determined complex dynamic modulus G* (in Pa) against the set-off resistance values (as determined above) is shown. FIG. 1 refers to intaglio inks which are formulated as given in Comparative Example 2 (“Standard”) and in Comparative Example 3 (“Standard without wax”), with variations as to the type and the quantity of fusible wax, as well as solvent content. These inks do not contain any UV-curable components. The four inks to the left correspond to comparative example 3 (i.e. inks without wax). The four inks to the right of the graph correspond to Comparative Example 2 and contain different kinds and concentrations of fusible waxes. A first set of complex dynamic modulus values was determined on the freshly prepared inks (otherwise as described above) (triangular points in FIG. 1 ). A second set of set-off resistance values and of complex dynamic modulus values was measured on the same inks after a thermal cycle, in which the ink's temperature was raised to 80° C. (i.e. the temperature of the printing plate) and cooled to 25° C. again (square points in FIG. 1 ). Only the square points represent a (dynamic modulus/set-off) value pair; the triangular points, corresponding to the not thermally cycled inks, do only represent the dynamic modulus values of the corresponding inks before printing and have been extrapolated from the square points with respect to the set/off resistance values. For determining set-off values, the inks must noteworthy be printed, and therefore mandatory pass through a thermal cycling. [0101] A glance at FIG. 1 shows that the inks without fusible wax (points to the left) show only a slight increase in G* after thermal cycling. These inks remain tacky after printing, and correspondingly produce set-off, as indicated by their lower set-off resistance values. The inks with fusible wax (points to the right) show a large increase in G* after thermal cycling. These inks lose their tackiness upon printing, and correspondingly avoid set-off, as indicated by their higher set-off resistance values. [0102] The observed increase in complex dynamic modulus after the heating/cooling cycle is an indicator of the ink's internal structural change upon printing. It can be seen that inks showing a large increase of the complex dynamic modulus G* (i.e. the group of inks to the right of the graph, which comprise fusible wax) upon thermal cycling have higher set-off resistance values than inks showing a small increase of the complex dynamic modulus (i.e. the group of inks to the left of the graph, without fusible wax). [0103] FIG. 2 illustrates the synergistic effect of the combination of fusible wax and UV-curable acrylate in an intaglio ink in preventing set-off after printing. The inks according to example 1 and comparative example 1 to 3 were applied as follows: A 15 micrometer thick layer of the ink in question was applied onto a 80° C. preheated glass plate using a SHINN applicator. The glass plate was placed at 80° C. in an oven for additional 10 seconds, then cooled to 25° C. again. Where indicated, the glass plate was then subjected to UV-irradiation (1 pass, 50 m/min, 150 W/cm, 2 UV lamps); this treatment is designated as “2×100 UV”. The ink layer was subsequently scratched off the glass plate with a spatula and measured on the AR1000 rheometer. [0104] FIG. 2 a shows a plot of the experimentally determined set-off resistance values (determined as described above) versus the complex dynamic modulus G* (in Pa as an absolute value). [0105] FIG. 2 b shows a plot of the set-off value versus the elastic component G′ (real part of G*; also called the storage modulus) of the measured complex dynamic modulus G*. [0106] FIG. 2 c shows a plot of the set-off value versus the plastic or viscous component G″ (imaginary part of G*, also called the loss modulus) of the measured complex dynamic modulus G*. [0107] The ink of example 1, comprising both wax and UV-curable acrylate, and subjected to the above thermal cycle, followed by UV-irradiation (“Modified 30+2×100 UV”), has the highest value of complex dynamic modulus G* (Pa), and also provides the best set-off resistance values of all investigated inks. The set-off properties furthermore correlate in the same way with both components of the complex dynamic modulus, i.e. with the elastic (G′) and with the plastic (G″) modulus; the latter being the more important contributor to the complex dynamic modulus. In particular, an unexpectedly high increase of the set-off resistance value after the above thermal cycle was observed with the ink of example 1. Said increase exceeded the respective increase of the set-off resistance value of the other examined inks by far. [0108] As can be inferred from FIG. 2 a , the UV-irradiation of the ink of the present invention led to a more than twofold increase of the complex dynamic modulus G*. Even for the same ink without wax, an about twofold increase of the complex dynamic modulus G* was observed. On the other hand, for the standard ink, with or without wax, UV-irradiation did not show any noticeable effect on the complex dynamic modulus G*. [0109] The cooperative effect of wax and UV-curable acrylate in preventing set-off was assessed as follows: FIG. 3 shows the intaglio-printed test image used to assess said set-off and drying properties of the inks. This test intaglio plate has different engraving depths, varying from shallow (fine-line pattern in the face and hair part), to middle-deep (hat part), to deep engraving (SICPA guilloches). The deep engraving yields the most sensitive parts on the printed image for assessing the set-off properties. The latter are assessed by subjecting a fresh print covered by a sheet of paper to a weight of 2 kg during 24 hours, then separating the sheet of paper from the print. The set-off image is the reverse of the printed image. [0110] FIG. 4 a - d illustrate the cooperative effect of a UV component and a fusible wax onto the set-off properties of the ink. The ink of example 1 was used in the cases shown in FIGS. 4 b and 4 d , whereas in the cases of FIG. 4 a and FIG. 4 c . the ink of comparative example 1 (i.e. the fusible wax (Carnauba wax) was replaced by 5% mineral filler) was used. In the cases shown in FIGS. 4 c and 4 d , a UV-irradiation as described above was carried out, whereas in the cases shown in FIGS. 4 a and 4 b , no UV-irradiation was carried out. [0111] In the absence of UV-irradiation and wax ( FIG. 4 a , comparative example 1), a bad set-off note (5.44) resulted. The presence of fusible wax ( FIG. 4 b , example 1) already considerably improved the set-off note (5.60). UV-irradiation in the absence of fusible wax ( FIG. 4 c , comparative example 1) gave a similar result (5.66). Set-off was completely absent ( FIG. 4 d , example 1) in the presence of fusible wax after UV-irradiation (note 5.90).

The present invention relates to printing inks for the intaglio printing process, also referred to as engraved steel die printing process. In particular, oxidatively curing inks comprising a combination of fusible wax and a UV curing binder component are disclosed. These inks can be printed on a standard printing press, and, through a short UV irradiation after printing, allow to significantly reduce or eliminate the undesired set-off which can occur after printing and stacking the printed sheets. Using the inks of the present invention results in less set-off contaminated printed sheets, allowing for a higher pile-stacking of the printed good, for the use of increased engraving depths, of a more challenging intaglio design, and for the printing on less porous substrates, whilst enabling the printing on a standard printing press, and offering the possibility of using a lower printing plate temperature.

This invention relates to the joining of dense bodies of refractory metal such as tungsten or molybdenum to carbonaceous bodies, and more particularly to the employment of reaction brazing at high temperature to join dense bodies of tungsten or molybdenum or alloys thereof to carbonaceous supports, such as graphite or carbon-carbon composites. Even more particularly, the invention relates to the reaction brazing of x-ray generating anodes made primarily of either molybdenum or tungsten, to graphite supports or to carbon matrix, carbon fiber-reinforced composite supports to produce assemblies suitable for use at high temperature in a vacuum environment where temperature cycling will be experienced and collectively would tend to result in undesirable chemical reactions, e.g. carbon diffusion from the support and formation of substantial metal carbide. BACKGROUND OF THE INVENTION There are various applications where it is desirable to attach a tungsten or molybdenum refractory body to a carbonaceous substrate in a manner so as to create an effective joinder that will remain satisfactory for extended periods in a high temperature environment, i.e. above 1000° C. and in certain instances above 1500° C. or even above 2000° C. One such use of such structures is in the field of rotating x-ray anodes, and U.S. Pat. No. 3,579,022 shows the creation of a rotary anode for an x-ray tube wherein a tungsten-rhenium alloy is bonded to a graphite base by first depositing a thin stratum of rhenium having a thickness of a few micrometers. In U.S. Pat. No. 3,649,355, a graphite base for a rotary x-ray anode is first plasma-sprayed with tungsten to produce a coating of substantially pure tungsten, or an alloy thereof with rhenium, osmium or the like. Thereafter, an outer layer of tungsten is preferably deposited from a gaseous phase using CVD or the like. In U.S. Pat. No. 3,689,795, a molybdenum or molybdenum alloy base having a thickness of about 6 millimeters is used, and a focal track of pure tungsten or a tungsten-rhenium alloy is applied thereto by chemical vapor deposition (CVD) or a like process. To improve the crack resistance of such a molybdenum base, it is suggested to form the base using powder metallurgical techniques from a mixture of metal powders so the base will contain from 50 to 500 ppm of boron. U.S. Pat. No. 4,132,917 shows a graphite body which has a metal band brazed thereon for a focal track. Illustrated in the patent is the use of a molybdenum or molybdenum alloy layer which is contiguous with the graphite body, and a layer of a tungsten-rhenium alloy that is superimposed thereon. In one embodiment, a thin coating of titanium carbide is applied to the graphite by CVD before brazing a metallic ring of the desired shape using Ti or Zr foil or powder paste, which ring may be formed by a powder metallurgical process. U.S. Pat. No. 4,516,255 discloses the use of a rotating x-ray anode made from a molybdenum alloy containing some carbon, such as TZM, which is provided with a focal path of tungsten or a tungsten alloy. Using plasma spraying or the like, an oxide coating, such as titanium oxide, is formed on the TZM body, preferably after an intermediate layer of molybdenum (Mo) or tungsten (W) having a thickness between 10 and 200 μm has been applied by plasma spraying or the like. U.S. Pat. No. 4,990,402 teaches joining a metal part to a fiber-reinforced pyrolytic graphite structure or the like such as a structure wherein which the fibers are irregularly arrayed. In order to solder a molybdenum alloy component, such as TZM, thereto, a solder is used which is 70% silver, 27% copper and about 3% titanium. Although such methods of joinder have proved reasonably effective for certain applications, the search has continued for improved methods of bonding dense refractory metal bodies, such as those of tungsten, molybdenum and their alloys, to carbonaceous supports by creating bonds that will exhibit excellent high temperature stability over a long term even in the face of a relatively substantial difference in coefficients of thermal expansion that would tend to create stresses at such a joint, while also resisting diffusion of carbon from such support into the dense refractory metal body. In addition, when the joinder is of an x-ray anode to a support, the thermal conductivity through the joint should preferably be adequate so that it does not create a heat flow choke that would deter heat being generated from flowing freely away from the anode, and the heat capacity of the support and its emissivity should be adequate to dissipate heat transferred to it. SUMMARY OF THE INVENTION The invention provides methods for joining bodies of refractory metal in elemental form to carbonaceous supports in a manner that creates a bond which is capable of withstanding temperatures at least as high as 1300° C. and preferably of at least 1500 to 1600° C. for substantial lengths of time, even higher temperatures for short periods, and perhaps more importantly of being able to withstand frequent cycling between far lower temperatures, e.g. close to room temperature, and such high temperatures. Alternative methods to certain preferred methods produce bonds which are capable of operating at a temperature of about 2000° C. or above. In certain of these preferred methods, a Reactive metal, preferably in the form of a foil, and a powder mixture containing a boride of the refractory metal being joined, a carbide of the Reactive metal, and preferably additional elemental metal, e.g. of the foil and/or the metal body, are introduced between complementary surfaces of the bodies being joined. This assembly is then heated to a reaction-brazing temperature (as hereinafter more specifically defined). For joining dense tungsten bodies, e.g. those made of single crystal tungsten or the like, an alcohol slurry of particles of tungsten boride plus a carbide of a Reactive metal, e.g. hafnium (Hf), carbide and/or zirconium (Zr) carbide, may be applied to the carbonaceous support, which slurry may also include some of these metals in elemental form. When a Mo or Mo alloy body is being joined, Mo boride is substituted for W boride. Reactive metal in the form of a paste or preferably a foil is juxtaposed with the W or Mo surface to be joined. The slurry does preferably contain powder of the Reactive metal of the foil (and also the metal of the carbide should it be different), and it also preferably contains W or Mo powder (depending upon the body being joined). The method produces a strong joint of low thickness having good thermal conductivity that is particularly valuable in the construction of an x-ray anode. The carbonaceous substrates may, for example, be dense graphite bodies or carbon-carbon composites wherein either bundles of carbon fibers or carbon filaments from woven cloth are oriented in a direction transverse to the surface of the dense refractory body being joined, which composites may also contain fibers oriented parallel to such surface. In a particular aspect, the invention provides a method of making an x-ray tube target anode, which method comprises providing a dense body of tungsten (W) or molybdenum (Mo) metal suitable for serving as a target anode to create x-rays, providing a carbonaceous support body capable of withstanding high temperatures under vacuum conditions and having a surface complementary to a surface of said dense body, coating said complementary surface of said support body with a layer of a material containing a mixture of particulate Hf carbide or Zr carbide and particulate tungsten boride or molybdenum boride, and joining said dense body to said carbonaceous anode support by introducing a layer of elemental hafnium (Hf) or zirconium (Zr) between said complementary surfaces of said support body and said dense body, juxtaposing said complementary surfaces of said dense body and said support, and heating to a reaction-brazing temperature under vacuum or an inert atmosphere such that said dense body thereafter strongly adheres to said carbonaceous support body. The resultant product allows good heat flow from the anode body into the support at its high temperature of operation. In a more particular aspect, the invention provides a method of joining a dense tungsten(w) or molybdenum(Mo) body to a carbonaceous support, which method comprises providing a dense W or Mo metal body, which body has one surface designated for joinder to another body, providing a carbonaceous support body capable of withstanding high temperatures in the absence of air, which support has a surface complementary to said designated surface of said dense body, coating said complementary surface of said support body with a layer of a material comprising a mixture of particles of a refractory metal boride and of a metal carbide, providing a Reactive metal layer and juxtaposing said two complementary surfaces with said layer therebetween, and joining said dense body to said carbonaceous support body by heating to a reaction-brazing temperature such that said refractory metal body thereafter strongly adheres to said carbonaceous support while an intermediate barrier forms between said two bodies which thereafter diminishes diffusion of carbon from said support body into said refractory metal body. In a still more particular aspect, the invention provides a method of joining a dense tungsten(w) or molybdenum(Mo) refractory metal body to a carbonaceous support, which method comprises the steps of providing a dense W or Mo refractory metal body, which body has one surface designated for joinder to another body, providing a carbonaceous support capable of withstanding high temperatures in the absence of air, which support has a surface complementary to said designated surface of said dense body, coating said complementary surface of said support with a layer of a material comprising a mixture of particles of a boride of the refractory metal of the body and of a Reactive or refractory metal carbide, juxtaposing said two complementary surfaces, and joining said refractory metal body to said carbonaceous support by heating to a reaction-brazing temperature of at least about 2200° C. such that said refractory metal body thereafter strongly adheres to said carbonaceous support and an intermediate barrier forms therebetween which diminishes diffusion of carbon from said support into said refractory metal body both during said joining step and later during use of said body in a high temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS Shown in FIG. 1 is a method of joining a dense refractory metal body to a carbonaceous support embodying various features of the invention. Shown in FIG. 2 is an alternative method of joining a dense refractory metal body to a carbonaceous support embodying various features of the invention. Shown in FIG. 3 is another alternative method of joining a dense refractory metal body to a carbonaceous support embodying various features of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS It has been found that the general desire to join a dense refractory metal body of tungsten or molybdenum to a carbonaceous substrate having a relatively low coefficient of thermal expansion (CTE), including carbon-carbon composites, can be very effectively achieved using reaction brazing in the presence of a refractory metal boride and a Reactive metal carbide. By “dense body of tungsten or molybdenum”, for purposes of this application, is meant a body having a density at least 80% of its theoretical maximum density (preferably at least about 90% and more preferably at least about 95%), which body contains elemental tungsten, elemental molybdenum or an alloy of either that respectively comprises at least about 90% tungsten or 90% molybdenum. By Reactive metal is meant a metal having a melting point of about 1600° C. or above which forms a carbide and which forms a eutectic with either Mo or W at a temperature below its melting point and below the respective melting point of Mo or W; elements from Groups IVb and Vb of the Periodic Table are preferred, with elements of Group IVb being more preferred and Hf and Zr being most preferred. One of the difficulties in creating a strong, stable bond between a carbonaceous substrate and a dense body of refractory metal such as tungsten or molybdenum, which bond will remain strong and stable for substantial periods of time at high temperatures, i.e. at least about 1300° C. and preferably at least about 1600° C., and conceivably of about 2000° C. is the accommodation of the stresses that necessarily result from the substantial differences in the linear CTEs. It is important to be able to produce a bond having a structure that will withstand the strains and stresses which necessarily will occur during substantial temperature excursions between ambient and operating temperatures because of the CTE differences. For example, at room temperature, the CTE of tungsten is about 4.5×10 −6 /° C., and the CTE of molybdenum is about 5.43×10 −6 /° C., and when there is a substantial difference between the CTE of the dense refractory metal body and that of a carbonaceous substrate (e.g. a fibrous composite substrate may have a CTE of about 1×10 −6 /° C. in the direction of orientation of the fibers whereas dense graphite substrates can vary from about 3-9×10 −6 /° C.), there is the distinct possibility of developing high strains at and near the interface of the bond during temperature excursions. Of course, such excursions are to be expected because high temperature operation for such structures is generally anticipated, as for example when the structure will serve as a rotating x-ray anode, because present x-ray tube anodes reach such high temperatures that their operation must be frequently interrupted to allow them to cool. Various carbonaceous supports are contemplated including graphite, pyrolytic graphite, fiber-reinforced pyrolytic graphite and carbon-carbon composites. Carbon-carbon composites, wherein carbon fibers are embedded in a carbon matrix, have become widely available in recent years and can be created with very good structural properties; accordingly, they have become one preferred material for use in high temperature structural applications, including use as a support base for a rotating x-ray anode. Such a carbon-carbon composite will generally have a density of at least about 1.7 g/cm 3 and an emissivity in the range of about 0.85 to 0.99 so as to allow for adequate dissipation of heat. Such composites may be fashioned from lay-ups having various orientations of carbon fiber arrays or graphite fiber cloths, and often they are fashioned from woven carbon fiber fabric or from bundles or tows of carbon fiber filaments that are suitably aligned in generally parallel fashion in alternating layers, although carbon-carbon composites having a three-dimensional carbon frameworks may also be used and may be preferred. When such a carbon-carbon composite is used for the base material to support a dense refractory metal body, the orientation is preferably such that the alignment of some of the bundles of fiber or of the woven sheets is transverse to, preferably perpendicular to, the juxtaposed surface of the refractory metal body being joined. The carbon fibers or filaments that are present in such composites have higher tensile strength in the axial direction, and because they are preferably aligned transverse to the surface of joinder, the joint will be stronger. Of course, when there is a three-dimensional carbon fiber framework, there will always be some carbon fibers that will be oriented transverse to any surface. Traditional carbonaceous supports for x-ray tube anodes utilize graphite having a density of at least about 75% of theoretical density. Graphite has a number of different crystalline forms, and the preferred graphite forms for use as a rotating anode support are those having a relatively high CTE approaching that of the metallic body. Although isotrophy is not considered to be a criterion of major importance, preferred graphites are those that would be categorized as being isotropic, as opposed to anisotropic. Such graphites are readily commercially available, as from Toyo Tanso and the Poco Graphite Co. One preferred graphite is Toyo Tanso grade IG-610U. While many early attempts at creating joints, as evidenced by some of the patents mentioned hereinbefore, utilized layers of tungsten or the like that had been deposited from a vaporous atmosphere, as by CVD, to serve as a focal path for a rotating anode for x-ray generation, it is believed that the durability of such an arrangement may be inherently limited as a result of the stresses mentioned hereinbefore, i.e. that would be created as a result of the difference in the CTEs, thus limiting the useful lifetime of such a structure. Another limitation on useful lifetime results from the effect that extremely high temperature at the joint would have on the thin metal and the adjacent carbon body. It has since been found that, by using a pre-prepared dense body of tungsten, e.g single-crystal tungsten, or of molybdenum, to support a tungsten focal track, structures having high temperature stability and durability can be created. Although elemental tungsten or elemental molybdenum may be used, an alloy of either TZM (99% Mo, 0.5% Ti, 0.07% Zr and 0.05% C, by weight) or TZC (having a somewhat greater amount of carbon) is often used, rather than Mo, because such has greater strength and is readily commercially available. Likewise, alloys of W, e.g. with a small amount of Re, might also be used. However, for a rotating x-ray anode, single crystal material, rather than polycrystalline material, may be preferred. In addition to creating a strong bond that will resist the strains expected to be experienced during high temperature excursions, it has also been found worthwhile that the joint should provide a thin but effective barrier to carbon diffusion therethrough from the support to the anode body. It is felt that a joint should preferably be constructed to retard the diffusion or migration of carbon from the support body; otherwise, a carbide zone may be formed not only within the region of the initial joint itself, but throughout an expanded region intruding into the surface regions of the anode. Such diffusion-resistance may be particularly of value in the field of x-ray anodes where longevity and continued high thermal conductivity during operation in a high temperature environment are important, because the thermal conductivity of such a metal carbide is substantially lower than that of the bodies being joined. Moreover, a fairly thick carbide zone is more prone to develop cracks as a result of thermal cycling because of inherent differences in CTEs. It is found that such an effective barrier to the creation of a relatively thick layer of metal carbide can be achieved as a part of a strong joint by coating the surface of the carbonaceous substrate, where joinder will take place, with a mixture that contains a particulate boride of the refractory metal body to be joined and a particulate Reactive metal carbide, preferably Hf carbide or Zr carbide. For example, if the intention is to join a dense body of tungsten to the carbonaceous support, an initial precursor layer in the form of a mixture of particulate tungsten boride and hafnium carbide may be applied to the appropriate surface of the composite. Such application may take place in any suitable fashion, and thereafter reaction brazing results in the creation of a relatively thin, strong joint of good overall thermal conductivity. When a Mo dense body is to be joined to a carbonaceous support, a particulate mixture of either Hf carbide or Zr carbide and Mo boride may be used which preferably comprises a major portion of the metal carbide and a minor portion of the metal boride. If for example instead a dense tungsten body is to be attached to a carbonaceous support, tungsten powder in combination with either hafnium or zirconium powder would preferably be used as a minor part of the particulate mixture being employed in the reaction brazing. The particles in such mixtures may range in size up to about 50 μm; however, preferably particles having an average size in the range of about 5 μm to about 25 μm and more preferably particles with an average size between about 5 μm and about 15 μm are used. Often the metal carbide will be present in an amount at least about 2-3 times the weight of the metal boride and more preferably about 2.5 to 3.5 times the weight of the metal boride. Such mixtures of particulate metal carbide and particulate refractory metal boride can be slurried with an alcohol and with a binder, such as a cellulose derivative, to create an adherent, paste-like material that can be conveniently first brushed as a viscous fluid onto the surface in question. The mixture being coated onto the carbonaceous substrate preferably also includes minor amounts of the elemental metals that are present in the carbide and boride constituents; for example, molybdenum or tungsten powder and hafnium or zirconium powder may be present, e.g. in individual amounts equal to about 10 to 20 weight % of the total particulate mixture. The particle size of the elemental metals can be about the same as set forth above, or they may be slightly smaller. As a general rule, such elemental metal powders are each preferably employed in an amount about equal to or within about 25% of the weight of the boride. Moreover, the amount of Mo or W powder should be approximately equal to the amount of Hf or Zr. Overall, Mo or W powder is preferably not employed at a weight percentage that is more than about 20% greater or less than that for the Hf or Zr, and preferably there is not more than about a 10% difference in the weight percents. They are most preferably employed in about equal amounts. Overall, the particulate mixture preferably consists essentially of between about 14% and about 20% by weight of the refractory metal boride, between about 45% and 56% by weight of the Reactive metal carbide, and between about 13% and about 19% each of Hf and Mo powders. More preferably, the mixture contains between about 15% and about 19% of MoB or WB and between about 46% and about 55% of hafnium or zirconium carbide, with the remainder preferably being essentially equal amounts of elemental hafnium and molybdenum. Once the surface has been coated with such a slurry, it may be heated to a temperature sufficient to sinter the boride and carbide particles, as depicted in FIG. 2, under vacuum conditions or in an inert atmosphere which is essentially devoid of O 2 , N 2 , H 2 , CO, CO 2 and SO x , (except for trace amounts such as might be present in high purity commercial gases), all of which are considered to be potentially deleterious to achieving strong bond having long-term stability. The time and temperature of the reaction-sintering step is adjusted as well known to those having skill in this art, depending upon the particular compounds that are present. For example, if the slurried layer includes molybdenum boride and hafnium carbide, a reaction-sintering step might be carried out at a temperature of about 1850 to about 1950° C. for about 20 to 30 minutes, after raising the coated substrate reasonably slowly to this temperature. As a result, there is an interdiffusion of metals and a reaction between the carbonaceous substrate and one or more of the metals and the boride-containing material in the slurry. Only partial melting occurs, and this phase wets and interacts with the carbon surface and create a very thin, adherent layer of hafnium and molybdenum carbide; this layer effectively diminishes the diffusion of carbon into the remainder of the braze region during the subsequent reaction-brazing step and during subsequent use. Although such pre-sintering is effective, it may be unnecessary as alternatively it has been found that such joinder of a dense refractory metal body to a carbonaceous support may be effectively carried out using a single heating step (FIG. 1) as described hereinafter following a brief description of this two-step process, depicted in FIG. 2 . Although use of a boride of the same refractory metal as the dense body that is to be joined is preferred, there are other options. For example, when a Mo body is being joined, one or more other compatible refractory or Reactive metal borides, such as tungsten boride, vanadium boride and/or zirconium boride, may be used either together with, or to the exclusion of, Mo boride. The tungsten boride may be WB, W 2 B or W 2 B 5 ; however, preferably W 2 B is used, particularly when a W body is being bonded. Similarly, the molybdenum boride may be MoB 2 , MoB, Mo 3 B 4 or Mo 3 B 5 ; preferably, however, MoB is used. A relatively thin, but continuous layer of such particulate material slurry is preferably applied so that the final thickness of the joint is about 0.007 in (0.18 mm) or less, preferably not greater than about 0.005 in (0.13 mm) and more preferably about 0.003 in (0.08 mm) plus or minus 0.001 in (0.03 mm). Although hafnium carbide is the more preferred carbide, instead of using hafnium carbide particles in this sintering mixture, zirconium carbide might be substituted for part or all of the Hf carbide. Alternatively, either might be used together with particles of molybdenum carbide, vanadium carbide, or tungsten carbide in the slurry for coating the carbonaceous surface. The second step of the preferred, somewhat lower temperature joining method introduces a layer of Hf or Zr between the surface of the dense refractory metal body and the reaction-sintered surface of the carbonaceous support; thereafter, reaction-brazing is carried out. The layer can be one of a dense paste of metal particles or metallic foil. Metal foil is preferably used, and it may be in the form of sheet material about 1-3 mils (0.001-0.003 in) in thickness. It is placed adjacent the surface of the dense refractory metal body to be joined and can be a single sheet or multiple sheets, depending in part on what is commercially available. For example, two sheets of 1 mil (0.001 in, 0.0254 mm) thick hafnium foil may be used to provide a layer 2 mils in thickness. When the single-step method (FIG. 1) is used, the foil layer is simply located atop the air-dried slurry-coated carbonaceous substrate. The introduction of a continuous layer of a paste mode of small Reactive metal particles is feasible but much less desirable. Then the dense refractory metal body is juxtaposed, and the reaction-sintering step is carried out. Regardless of whether the one-step or the two-step method is used, the composition of the reaction braze material will be essentially the same. As previously mentioned, the material should include a mixture of a refractory metal boride and a Reactive metal carbide, preferably with additional compatible elementary Reactive and refractory metals, e.g. Hf and Mo powder. As earlier mentioned, the braze material is applied as a mixture of a binder and such particulate materials, preferably as an alcohol slurry of a binder and the particulate/powder mixture, using a suitable alcohol, such as ethyl alcohol. A cellulose derivative or a comparable organic binder, that will be removed by dissociation and volatilization during the subsequent heating to the reaction-sintering temperature, is preferably used to create a fluid mixture having the consistency of a flowable paste that can be uniformly brushed or otherwise suitably applied onto the carbonaceous surface. Once the braze material coating has been applied, it is heated in air to cure the binder. For example, heating to 125° C. for about 12 hours will partially polymerize a cellulose binder and vaporize the alcohol. Clean foil which is free of contaminants is then placed to cover the overall coated surface of the substrate, and the dense refractory metal body is lightly pressed thereatop, sandwiching the foil therebetween to prepare the assembly for the thermal braze cycle. Either gravity or preferably a small weight placed atop the dense refractory body is relied upon during the reaction-brazing cycle to maintain the surfaces in juxtaposition with each other. For example, it may be desirable to have a pressure of about 0.2 to 0.8 psi on the foil. The thermal cycle which is used will generally include staged heating as described hereinafter to a temperature at or near that of the desired reaction-brazing temperature. The staged heating up to the reaction-brazing temperature will usually take place over at least 1 hour and preferably over about 2 hours or more. The reaction-brazing temperature should then be held for a period of at least 10 minutes, more preferably at least about 15 minutes, and most preferably over at least about 20 minutes. This arrangement assures that the surface of the metal body alloys with the thin foil, the alloy (eutectic phase) of which also participates with the boride and carbon that may be present to form additional carbides en route to forming a strong, stable reaction-brazed joint, which includes a thin barrier layer of refractory metal carbide and eutectoid phases which collectively diminish diffusion of carbon from the carbonaceous substrate into the upper region of the joint and the dense refractory metal body during future high temperature operation. Moreover, it is believed that the presence of the elemental Hf and/or Zr and the elemental Mo or W are helpful in creating an eutectoid (i.e. solid state) reaction wherein there will be such a metallic alloy zone on the Mo body (or W body) side of the carbide layer. For example, it may be a solid solution of Hf and HfMo 2 that, at and above the eutectic temperature, forms a liquid solution of about 28 weight % Mo and about 72 weight % Hf which dissolves some MoB and carbon; however, there is a reversal during cooling below 1865° C. where an Hf-rich solid solution and the compound HfMo 2 form from the liquid phase. Then, after cooling to about 1230° C., a eutectoid (i.e., solid state) reaction occurs wherein the Hf-rich solid solution phase decomposes to a Hf phase of low Mo solubility plus additional of the compound HfMo 2 ; i.e. Hf(β)←Hf(α)+HfMo 2 . It is felt important that the resultant joint be able to accommodate such thermal cycling, to which an X-ray target anode and other such devices will be subjected, where the temperature exceeds the eutectoid temperature (1230° C.) so that this repeated eutectoid reaction will be experienced within the joint. One example of the preparation of a carbon-carbon composite suitable for joinder as a support for an x-ray anode employs commercially available carbonaceous material which is at least about ½ inch in thickness and which has Z-axis fiber bundles that are oriented substantially perpendicular to the surface at which bonding is to be achieved. The composite is cleaned in ethanol using ultrasonic cleaning and then baked under vacuum conditions at about 1000° C. for an hour, followed by baking at a temperature of about 2600° C. for about 10 to 15 minutes, to remove any volatiles that might otherwise potentially have an adverse effect upon the integrity of the joint. One preferred alternative material is dense graphite such as that available from the Toyo Tanso Co. of Japan as their grade:IG-610U. Generally, the graphite is preferably isotropic and should have a density of at least about 75% of its theoretical density of 2.26 gm/cm 3 , e.g. about 77 to 80%; it should have a coefficient of thermal expansion of at least about 5×10 −6 /° C., but preferably not greater than about 6×10 −6 /° C. Such graphite should also have a thermal conductivity of at least about 100 W/m° C. As previously indicated, the preferred brazing material is a slurry of a mixture of particulates together with an organic binder in a suitable organic solvent, e.g. ethyl alcohol. The binder may be a cellulose compound, such as hydroxypropylcellulose, or any other commercially available organic binder that will be removed as a result of heating under vacuum conditions or leave no more than a minute carbon residue. The metal carbide particles and the refractory metal boride particles may be of about the same size range. Generally, the particle sizes between about 50 μm and about 5 μm may be used, and particles which pass through a 325 mesh (45 μm) screen may be used, but particles between about 5 μm and about 15 μm are generally preferred. Although elemental Reactive and refractory metals may also be used in the same particle size range, these materials are commercially available in powder form; thus, molybdenum and/or tungsten and hafnium and/or zirconium are conveniently supplied as powders in a size between about 20 μm and about 5 μm. The slurry layer is preferably applied in a thickness so as to result in a joint which is about 2 mils (about 50 μm) thick without the contribution of the foil. The reaction-brazing temperature will vary somewhat depending upon the materials that are being used, but the assembly will generally be held at such temperature for at least about 15 minutes. Very generally, a temperature well below the melting point of the dense refractory metal, i.e. molybdenum or tungsten, is chosen so that melting of such clearly does not occur. However, the temperature should be sufficiently high so that a eutectic is formed between the foil, a minor amount of the metal powder and the Mo or W material at the surface being bonded; this eutectic takes part in creating a strong bond at this surface during the reaction-brazing step. For example, molybdenum is considered to have a melting point of about 2890° K. (2617° C.), and whereas alloys of Mo with hafnium (M.P. of 2503° K., 2230° C.) have a measured eutectic point at about 1930° C., it appears to be depressed to about 1865° C. as a result of the presence of carbon and the boride phase. Thus, it is found that operation can be carried out at a temperature slightly below the measured eutectic point for a system using the two metals, i.e. molybdenum and hafnium, and will produce a very effective braze as part of this overall novel joining method. Accordingly, in such a system, a reaction-brazing temperature between about 1835° C. and 1895° C. is preferred, with a temperature between about 1850° C. and about 1880° C. being more preferred and a brazing temperature of about 1865° C. being most preferred. Alternatively, when zirconium carbide and zirconium powder are included in the slurry instead of hafnium carbide and hafnium powder, the measured eutectic temperature of Zr (M.P. of 2125° K., 1852° C.) and Mo is lower, i.e. about 1520° C.; accordingly, such a reaction-brazing might be carried out at a temperature below 1500° C., e.g. about 1460° C., or at a higher temperature if desired. When tungsten or an alloy thereof is used as the dense refractory material, although it has a much higher melting point, i.e. about 3680° K. (3407° C.), it also forms a eutectic with hafnium at close to the eutectic temperature of Mo and Hf, i.e. about 1930° C. Accordingly, brazing temperature ranges below 1900° C., as generally mentioned above, should also be appropriate for W/Hf. Moreover, pure tungsten and zirconium form a eutectic at a temperature of about 1660° C., so temperatures about 20 to 30° C. below this may be suitable for reaction-brazing using a comparable mixture containing W and Zr. However, somewhat higher brazing temperatures, e.g. up to the measured eutectic temperature of the refractory metal of the body and the Reactive metal in the slurry, may generally be used without detriment. In fact, if even higher operational temperatures should be desired, a higher temperature operational joint may be produced, as described hereinafter, by reaction-brazing W to C using a particulate mixture of WB and HfC or WC that is devoid of significant amounts of elemental metals so that the eutectic does not include contribution from an elemental Reactive metal. The amount of alcohol and/or organic binder in the mixture is not particularly critical so long as potential separation of the various particle fractions is prevented, i.e. to prevent partitioning as a result of different weights or densities. It is generally satisfactory that a sufficient amount of binder is used so as to provide integrity in the coated layer, i.e. so that it will remain in place on the surface and there will be uniformity of particle distribution throughout. The thickness of the coated layer will usually be between about 0.5 mil and about 3 mils (0.076 mm) and preferably between about 1 mil and 2 mils (0.051 mm). Once the surface of the substrate has been coated to provide a layer of the appropriate depth, the binder is cured by heating in air for about 12 hours while the alcohol is volatized. The foil sheet or sheets are then positioned thereatop and sandwiched between this coated surface and the dense refractory metal body being joined. A weight is preferably added to the assembly so that gravity will create a light pressure during the reaction-brazing step. Generally, the amount of weight should be equal to the weight of the dense refractory metal body plus or minus about 50%; in one experiment, weight was added to create a normal pressure stress of 0.4 lb/in 2 (0.00276 MPa) which proved adequate. As previously mentioned, the heating (and preferably the cool-down) preferably take place in stages to bring the assembly from ambient or room temperature up to the reaction-brazing temperature, where it will be held for a period of at least about 15 minutes and then returned it to ambient. Such stages may be varied with some amount of latitude; for example, the temperature may be raised at a substantially linear rate from ambient to about 700° C. over a time of about 60 to 90 minutes, although a shorter period may be used. Thereafter, the temperature is preferably raised to the desired reaction-brazing temperature in two or three increments, with brief soakings preferably being used at such intermediate incremental temperatures to assure that temperature gradients within the assembly are minimized. Likewise, upon the initial stage of cooling, a slower rate is preferred to enable any liquid phase to solidify uniformly in place within the assembly, thereby preventing radial flow and the potential creation of voids in the joint. The following examples describe methods presently preferred for the reaction-brazing of such materials and constitute the best mode known by the inventors for carrying out the invention. However, they should be understood to be merely exemplary and not to constitute limitations upon the scope of the invention which is set forth in the claims that are appended hereto. EXAMPLE I Preparations are made to join a graphite ring machined to have an outer diameter of about 5.35 inches (13.59 cm) and an inner diameter of about 2 inches (5.08 cm) to a disk of TZM (molybdenum alloy) of about the same outer diameter (about 5.25 in) which has a central hole of 0.5 inches (1.3 cm) and a thickness of 0.416 inch (1.06 cm) at its greatest thickness. The TZM disk has a flat lower surface and a beveled top surface so that its thickness is greater in the center at the region of the half-inch hole. The graphite ring is machined from IG610U near-isotropic, medium grain, fine porosity graphite having a CTE of about 6×10 −6 /° C., which is relatively close to the CTE of molybdenum, i.e. 5.43×10 −6 /° C. The graphite ring has a thickness of about 2 inches at its center and a bevel toward its outer circumference. The planar face of the graphite ring was ground using abrasive paper having a silicon carbide grit of Mesh Size No. 240 and then cleaned using ultrasonic cleaning in ethanol. After pumping the cleaned part free of alcohol under vacuum, it was subjected to a high temperature bake-out along with a similarly cleaned ¾ inch diameter graphite sample that was to be used as a process control and microstructure analysis specimen. Heating of the graphite parts was carried out for about 30 minutes at 1920° C. under a vacuum of about 10 −4 Torr. This bake-out releases and disperses any volatiles that might otherwise be released during the subsequent reaction-sintering and potentially form undesirable porosity in the liquid phase of the reaction-braze material. A brazing slurry is then formed from a particulate/powder mixture in alcohol, i.e. ethanol, using a solution of 99 parts ethanol and 1 part hydroxypropylcellulose, which was stirred to obtain a solution of transparent clarity and stored so as to prevent absorption of water from the atmosphere. All of the powders used had greater than 99.5% purity. All were of less than 325 mesh size (about 45 μm), and most of them had an average particle size of about 10 μm, being generally between about 5 μm and about 20 μm. The powder mixture was formulated using four different powders in the following weight percents: Hf—16%, Mo—16%, MoB—17% and HfC—51%. Each powder was individually added to the solution and mixed to achieve 10 parts of this powder mixture in 6 parts by weight of the cellulose alcohol solution; it was then stirred slowly by hand with a Teflon stir rod for about 20 minutes to thoroughly mix it and obtain a uniform gray-colored slurry of viscous but pourable and paintable consistency. The top surfaces of the graphite ring and the ¾ inch diameter graphite cylinder were then coated with the powder slurry. The graphite ring weighed about 886 grams, and about 4 grams of the powder slurry were applied uniformly across the flat face of the graphite ring that had an area of about 19.33 in , i.e. about 1 gram of powder slurry per 5 sq. in. Painting was carried out by hand using an artist-quality bristle paint brush. The slurry was applied in layers and allowed to air dry. The graphite ring and the test cylinder were periodically weighed until the desired amount of the powder mixture had been applied to both. Once these levels were achieved, the graphite parts, with the powder slurry-coated faces positioned upwards and horizontal, were heated in a convection oven at about 125° C. allowing the cellulose binder to cure in air over 9 to 10 hours, during which time ethanol and any water that might be present evaporated. The parts were then removed, allowed to cool and then associated with hafnium foil. Two rings of hafnium foil, each about 0.001 in. (0.025 mm) thick, were used; each had an O.D. just slightly less than the O.D. of the graphite ring and slightly greater than the O.D. of the TZM ring, which is about 5.25 in.(13.34 cm) and an I.D. slightly smaller than the I.D. of the graphite rim. Assemblies are then created with the hafnium foil disposed horizontally upon the slurry-coated flat surfaces of the graphite support and with the TZM ring resting upon the Hf foil. A similar TZM disk having a flat lower surface is used to overlie two circular disks of Hf foil on the test cylinder. Three metal weights of tungsten and tantalum were then positioned atop the TZM disk to bring the total weight bearing upon the hafnium foil disks to about 2836 grams, which corresponds to a downward pressure of about 0.4 psi over the surface area of about 19.33 square inches. The test sample was similarly weighted. The two assemblies were then transferred to a vacuum furnace having tungsten heating elements disposed within a water-cooled exterior boundary, which was then evacuated to about 9×10 −6 Torr. Heating was carried out at a rate of about 600° C. per hour until a temperature of about 700° C. was reached, at which time the temperature was held for about 5-15 minutes (soaking). The rate of heating was then increased to about 1,000° C. per hour, which rate was thereafter used. Once the target temperature of 1200° C. was reached, it was held for 5-10 minutes, and after 1600° C. was reached, it was held for about 10-20 minutes. Heating was then continued to about 1865° C., the desired reaction-brazing temperature, and the assembly was held at this temperature for 20-30 minutes at a furnace pressure of about 1×10 −4 Torr. As the temperature rises, the Hf foil becomes joined to the Mo alloy body by solid-state diffusion reaction and by the eutectic reaction, i.e. solid Hf (alloyed with Mo) phase+HfMo 2 phase forms liquid eutectic phase at eutectic temperatures. Following completion of the reaction-brazing step, the assemblies were slowly cooled at a rate of about 200° C. per hour for the first 100° and held at about 1765° for about 10 minutes. Cooling at the same rate to 1600° was then effected, and this temperature was held for about 1 minute. The rate of cooling was then increased to about 1000° C. per hour until about 600° C., where the rate gradually slowed as radiative cooling efficiency begins to diminish. After ambient temperature was reached, e.g. below about 40° C., the furnace vacuum was ended, and pressure was returned to atmospheric. Visual examination of the parts shows that brazing is uniform about the entire periphery and that the Hf foil has formed a smooth substantially continuous fillet at the outer surface of the juncture. Both assemblies were examined under a stereomicroscope at magnifications between 3× and 10×, and no evidence of any microcracks was detected. Examination was then carried out using x-ray radiography, and the results were negative indicating that there appeared to be no substantial defects present in the joint region of either assembly. The smaller assembly was then mounted in epoxy and cross-sectioned across a diameter of the cylinder. It was then remounted in epoxy which was cured to create a metallographic mount. Using standard metallographic grinding and polishing techniques, the cross-section was prepared and then examined in a scanning electron microscope to observe the microstructure in the joint region and check for any voids or large pores, cracks or other nonuniformities; none were found. Measurements of the joint thickness were made, and the thickness was found to be between about 0.0025 and about 0.003 inch (0.064 and 0.076 mm). Based upon these observations, it is concluded that this reaction-brazing has resulted in the creation of a molybdenum disk supported upon a dense graphite substrate that will be excellently suited for use as a rotating anode in commercial x-ray tubes because a strong, defect-free bond has been achieved as a result of this reaction-brazing process. EXAMPLE II A procedure as generally set forth in Example I is carried out using a 2-inch diameter graphite ring and a TZM disk of comparable size. Following application of the slurry to the flat surfaces of the graphite ring substrate and a test cylinder, they are reaction-sintered in accordance with the-two-step process depicted in FIG. 2 . The coated graphite supports are placed in the vacuum furnace under the same vacuum conditions and heated to a temperature of about 1945° C. over a time period of about 2 hours and 30 minutes using a very similar heating schedule to that previously described. Once this reaction-sintering temperature is reached, the coated supports are held at this temperature for about 30 minutes. Thereafter, heating is discontinued, and the furnace is cooled to ambient temperature using a schedule essentially the same as in Example I. Thereafter, the two rings of hafnium foil are inserted atop the sintered layer, and a TZM disk is placed thereatop and weighted generally as described in Example I. The test cylinder is separately assembled as before. The assemblies are then returned to the vacuum furnace, and reaction-brazing is carried out using the time and temperature schedule set forth in Example I heating to a temperature of about 1865° C. Following cooling down under similar conditions to Example I, the assemblies are removed, and examination and cross-sectioning of the test cylinder show that a strong, uniform joinder of the bodies has been achieved. In order to test the longevity and other characteristics of the reaction brazes that are being obtained, the Example II sample and a comparable 2-inch diameter sample fabricated according to the process of Example I are soaked for about 50 hours at about 1600° C. in the vacuum furnace under a vacuum of about 10 −4 Torr. Following such soaking at 1600° C., the samples are caused to cycle between 1600° C. and 750° C., being repeatedly allowed to drop over about 50 minutes to 750° C. before raising the temperature back to 160° C. over the next 50 minutes. This process is repeated 20 times so that the samples have each been subjected to 21 thermal cycles. Each time, the samples are held at the 1600° C. level for about 10 minutes and are similarly held at the 750° C. level for about 10 minutes; this constitutes a severe test cycle designed to test the suitability of the product to withstand the cycling that a rotating anode would be expected to experience. Following the 1600° soak and the 21 cycles as described, the joined bodies are examined by X-ray radiography and otherwise, and the bonds appear to be continuous and strong. When the samples are cross-sectioned transverse to the joint and subjected to metallographic examination, it is seen that the thickness of the joint has not grown and that there are only minor amounts of molybdenum carbide and molybdenum boride phases in the grain boundaries of the TZM body adjacent to the joint microstructure of the assemblies made using the one-step method of Example I. A very thin continuous layer of hafnium-rich carbide (equal to about 20% of the thickness of the joint) extends throughout the entire circular area and has remained substantially the same thickness as when it was formed by reaction-brazing. This continuous carbide layer and the balance of the joint microstructure of carbide and boride discrete phases, in conjunction with the Hf plus HfMo 2 eutectoid phase form a very effective barrier to carbon migration from the graphite substrate into the dense molybdenum alloy (TZM) body. The foregoing is confirmed by microhardness readings. Examination of the Example II sample shows a quite similar joint microstructure; however, there is included a thin zone of molybdenum carbide/boride phase that is formed generally adjacent the eutectoid rich zone of the joint that appears to have resulted from C and B diffusion during the high temperature test exposure following the initial reaction-sintering step. However, because the joint thickness has remained about the same and prevented growth of a thick carbide zone into the TZM alloy body, the sample retains good thermal conductivity across the bond (as does the sample from the method of Example I) which is an important feature for a rotating x-ray anode. Both methods produce quite acceptable resultant products and are considered to be very well-suited for manufacturing rotating x-ray anodes that can be used for a substantial length of time at temperatures in the range of 1500-1600° C. without suffering deleterious consequences. The somewhat simpler one-step process is considered to be presently preferred because of the economics of its practice; moreover microscopy examination shows that there is a lesser indication of carbon and/or boron diffusion, i.e. there is detection of a lesser, minor presence of carbide-boride phases, which are only in the grain boundaries of the adjoining Mo alloy body, and only a minimal increase in microhardness. EXAMPLE III A procedure as generally set forth in Example I is carried out using a 2-inch diameter carbon-carbon composite ring and a single crystal W disk of comparable size. A brazing slurry is formed from a particulate/powder mixture in alcohol, i.e. ethanol, using a solution of 99 parts ethanol and 1 part hydroxypropylcellulose. The powder mixture is formulated using equal weight percents of tungsten boride and tungsten carbide and is mixed to achieve 10 parts of this powder mixture in 6 parts by weight of the cellulose alcohol solution. The top surfaces of the carbon-carbon ring and the test cylinder are coated with the powder slurry by painting by hand using an artist-quality bristle paint brush. The slurry is applied in layers and allowed to air dry. The ring and the test cylinder are periodically weighed until the desired amount of the powder mixture has been applied to both. Once these levels are achieved, the carbon-carbon parts, with the slurry-coated faces positioned upwards and horizontal, are heated in a convection oven at about 125° C. allowing the cellulose binder to cure in air over 9 to 10 hours, during which time ethanol and any water that might be present evaporate. The parts are then removed, allowed to cool and then reaction-sintered as generally depicted in FIG. 3 . The coated carbon-carbon supports are placed in a high temperature furnace under the same vacuum conditions; the furnace is back-filled with argon and heated to a temperature of about 2350° C. over a time period of about 1 hour using a heating schedule similar but more rapid than that previously described. Once this reaction-sintering temperature is reached, the coated supports are held at this temperature for about 7 minutes. Thereafter, heating is discontinued, and the furnace is cooled to ambient temperature using a schedule essentially the same as in Example I. Thereafter, each sintered layer is coated with a second layer of the same slurry material, which may optionally include up to about 5% of carbon powder, and then similarly air-dried. A single-crystal W disk is placed thereatop and weighted generally as described in Example I. The test cylinder is separately assembled as before with a similar W disk. The assemblies are then returned to the vacuum furnace, and reaction-brazing is carried out in vacuum, or optionally in inert gas, using a time and temperature schedule generally as set forth in Example I but heating to a final temperature of about 2350° C. and holding that temperature for about 10 to 15 minutes. Following cooling down under a similar schedule as that in Example I, the assemblies are removed, and examination and cross-sectioning of the test cylinder show that a strong, uniform joinder of the bodies is achieved and that the single crystal W disc will be excellently suited for use as a rotating anode in commercial x-ray tubes because its character will allow its operation at a temperature as high as about 85% of the reaction-brazing temperature, e.g. about 2000° C. Although the invention has been described with regard to certain preferred embodiments, it should be understood that various modifications and changes as would be obvious to one having the ordinary skill in this art may be made without departing from the invention which is set forth in the claims which are appended hereto. For example, other dense graphite such as dense pyrolytic graphite may be used; by “dense” is generally meant having at least about 75% of theoretical maximum density, with at least about 90% being preferred. Likewise, carbon fiber-carbon matrix composites having a density of at least about 1.7 gm/cm 2 may also be employed. Other solvents and binders as well known in this art may be employed as they do not take part in the final brazing step. The disclosures of all U.S. patents mentioned hereinbefore are expressly incorporated by reference. By major amount is meant at least about 40 weight %, and by minor amount is meant not more than about 25 weight %. By a temperature of about a certain number of degrees is meant plus or minus 20 degrees. Particular features of the invention are emphasized in the claims that follow.

Reaction-brazing of tungsten or molybdenum metal bodies to carbonaceous supports enables an x-ray generating anode to be joined to a preferred lightweight substrate. Complementary surfaces are provided on a dense refractory metal body and a graphite or a carbon-carbon composite support. A particulate braze mixture comprising Hf or Zr carbide, Mo or W boride, Hf or Zr powder and Mo or W powder is coated onto the support surface, and hafnium or zirconium foil may be introduced between the braze mixture and the refractory metal body complementary surface. Reaction-brazing is carried out at or near the eutectic point of the components, which may be influenced to some extent by the presence of carbon and boride. Heating to about 1865° C. for a Mo/Hf combination creates a thin, dense, strong braze that securely joins the two bodies and creates a thin barrier of carbide and boride microphases near and along the interface with the carbon support that diminishes carbon diffusion into the metal body during extended exposures at elevated temperatures (above those presently used in x-ray tubes), even well above the eutectoid temperature.

FIELD OF THE INVENTION [0001] The present invention relates to the use of flavone derivatives as TNFα (tumor necrosis factor-α) antagonists or inhibitors. BACKGROUND OF THE INVENTION [0002] Flavonoids are a group of polyphenolic compounds exhibiting a variety of important bioactivities such as anti-inflammatory, antihepatotoxic and anti-ulcer actions. They also inhibit enzymes such as aldose reductase and xanthine oxidase. They are potent antioxidants and have free radical scavenging abilities. Many have antiallergic, antiviral actions and some of them provide protection against cardiovascular mortality. They have been shown to inhibit the growth of various cancer cell lines in vitro, and reduce tumour development in the experimental animals (Narayana et al., Indian Journal of Pharmacology 2001; 33: 2-16). [0003] Flavonoid compounds disclosed in WO 01/64701, or U.S. Pat. No. 6,706,865, has a chemical structure of formula (II) in which R 8 is a substituted or unsubstituted phenyl group; R 7 is a hydrogen atom or a hydroxyl group; and n is an integer of 1 to 4 and have reductase inhibitory effect, active oxygen extinguishing effect, carcinogenesis promotion inhibitory effect, anti-inflammatory effect, and so on. Astilbin is a flavanone represented by the following formula (III) and is one of digydroflavonol glycoside isolated from root of Astilbe thunbergii Miq. , which is gerbaceous perennial of saxifragaceous, as well as from the plant matter of Asmilaxylabra, Engelhardtia, Lyoniaovalifolia, Engelhardtiachrysolepos, Chloranthus glarber, Astilbe, microphylla, and so on. Astilbin has been reported to exhibit some important bioactivities such as aldose redutase inhibitory effect, active oxygen extinguishing effect, carcinogenesis promotion inhibitory effect, anti-inflammatory effect, and so on (Japanese Patent Publication Nos. 97/30984, 94/247851, and 94/256194), and therefore, astilbin is to be a very useful compound as anti-allergic drug or anticancer drug. However the anti-inflammatory mechanism has not yet been established. Of the several inflammatory mediators known to date, TNFα is one of by far the most potent and characterized cytokines, it is selected to test whether flavone derivatives inhibit the binding of TNFα to TNFα-R1 by L929 cell proliferation/cytotoxicity assay. [0004] TNFα plays an important role in the host defense. It causes resistance to many pathogenic microorganisms and some viruses. Even if TNFα has undoubtedly a beneficial function (mainly on the systematic level), it could lead to pathological consequences. TNFα plays a significant role in the pathogenesis of septic shock, characterized by hypotension and multiple organ failure among others. TNFα is the main mediator of cachexia characterized by abnormal weight-loss of cancer patients. Often TNFα is detected in the synovial fluid of patients suffering from arthritis. There was a broad spectrum of diseases, where TNFα could play an important role. Compounds binding with TNFα may be therefore useful in the treatment of numerous pathologies in which TNFα is involved, such as rheumatoid arthritis, Crohn's disease, plaque sclerosis, septic shock, cancer or cachexia associated with an immunodeficiency. SUMMARY OF THE INVENTION [0005] It has been found by the present inventor that a flavone derivative of formula (I) in which R 1 , R 2 , R 3 , R 4 and R 5 independently represent hydrogen, hydroxy or an ester group; R 6 represents hydrogen, hydroxy, an ester group or an O-glycoside group such as O-rhamnose, O-glucoside, O-retinoside or O-xyloside; and represents a single bond or a double bond; or the pharmaceutically acceptable salt thereof is useful for inhibiting the binding of TNFα to TNF-R1 or the release of TNFα and therefore may be used as TNFα antagonists or inhibitors in the treatment of numerous pathologies in which TNFα is involved, such as rheumatoid arthritis, Crohn's disease, plaque sclerosis, septic shock, cancer or cachexia associated with an immunodeficiency. It is found that Myricitrin, quercitrin and quercetin-3-D-glucoside exhibit an inhibitory activity with IC 50 values of 116.03, 160.77 and 95.74 μM on L929 cell proliferation/cytotoxicity assay without cell cytotoxicity. In addition, in the animal model of collagen-induced arthritis, the flavone derivatives exhibited 50% inhibitory activity. The flavone derivatives are promising sources with high TNFα inhibitor or antogonist activity. [0006] Therefore, the first aspect of the present invention is a pharmaceutical composition for antagonizing or inhibiting TNFα in a mammal, including human, comprising an amount of a compound of formula (I) or the pharmaceutically acceptable salt thereof effective in antagonizing or inhibiting TNFα and a pharmaceutically acceptable carrier. [0007] The second aspect of the present invention is a pharmaceutical composition for treating a disease or condition for which a TNFα antagonist or inhibitor is indicated in a mammal, including human, comprising an amount of a compound of formula (I) or the pharmaceutically acceptable salt thereof effective in antagonizing or inhibiting TNFα and a pharmaceutically acceptable carrier. [0008] The third aspect of the present invention is a method for antagonizing or inhibiting TNFα in a mammal, including human, comprising administering to said mammal an amount of the compound of formula (I) or the pharmaceutically acceptable salt thereof effective in antagonizing or inhibiting TNFα. [0009] The fourth aspect of the present invention is a method for treating a disease or condition for which a TNFα antagonist or inhibitor is indicated in a mammal, including human, comprising administering to said mammal an amount of the compound of formula (I) or the pharmaceutically acceptable salt thereof effective in antagonizing or inhibiting TNFα. BRIEF DESCRIPTIONS OF THE DRAWINGS [0010] The accompanied drawings are to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. [0011] FIG. 1 is a HPLC chromatogram of Chamaesyce hirta ( L ) Millsp. methanolic extract. [0012] FIG. 2 shows the results of L929 cellular assay of Chamaesyce hirta ( L ) Millsp. methanolic extract. [0013] FIG. 3 illustrates the isolation of quercitrin and myricitrin from Chamaesyce hirta ( L ) Millsp. methanolic extract. [0014] FIG. 4 is a HPLC chromatogram of quercitrin. [0015] FIG. 5 is a HPLC chromatogram of myricitrin. [0016] FIG. 6 shows the results of L929 cellular assay on quercitrin. [0017] FIG. 7 shows the results of L929 cellular assay on myricitrin. [0018] FIG. 8 is a LC/MS chromatogram of quercitrin. [0019] FIG. 9 is a LC/MS chromatogram of myricitrin. [0020] FIG. 10 is the 1 H-NMR spectrum of quercitrin. [0021] FIG. 11 is the 1 H-NMR spectrum of myricitrin. [0022] FIG. 12 shows the results of inhibition assay on myricitrin, quercitrin and quercetin-3-D-glucoside. [0023] FIGS. 13-1 to 13 - 10 show in vivo test results by using rats with collagen-induced arthritis. DETAILED DESCRIPTION OF THE INVENTION [0024] The compound of formula (I) may be administered to mammals via oral, parenteral (such as subcutaneous, intravenous, intramuscular, intrasternal and infusion techniques), rectal, intranasal, topical or transdermal (e.g., through the use of a patch) routes, etc. The compound of formula (I) or the salt thereof may be administered alone or in combination with pharmaceutically acceptable carriers or diluents by any of the routes previously indicated, and such administration may be carried out in single or multiple doses. Suitable pharmaceutical carriers include solid diluents or fillers, sterile aqueous media and various non-toxic organic solvents, etc. [0000] Experiments [0000] 1. Preparation of the Methanolic Extract of Chamaesyce hirta ( L ) Millsp. [0025] Possible TNFα inhibitor candidates were found in herbal ingredients fractionated by HPLC from herbal extract. Fifty grams of Chamaesyce hirta ( L ) Millsp. was washed and dried. Methanol was added to the weighed herb (10/1, v/w) to extract the herbal ingredients at room temperature for 3 days. The extract was filtered and the filtrate was concentrated under rotatory evaporator (Heidolph Laborota 4000) until the volume was reduced to about 50 mL. ( FIG. 3 ) [0000] 2. HPLC Analysis of the Methanolic Extract Obtained From Chamaesyce hirta ( L ) Millsp. [0026] Then a separation procedure was performed. One hundred μl of the concentrated filtrate of the herb extract was applied to a pre-equilibrated HPLC system (Shimadu). A TSK Gel 80™ reverse phase column (TOSOH) was used for separation. The solvent used for separation was double distilled water and absolute ethanol at 0˜100% gradient for 96 minutes at a flow rate of 0.75 mL/min. [0027] One-minute fractions were collected and dried using SpeedVac (Savant). Each fraction was re-dissolved in 100 μl 10% ethanol for screening for TNFα inhibitors. The fractions with TNFα inhibitor activity were then further purified by HPLC until the purity was more than 95%. [0028] A compound having TNFα inhibitor activity was found in the methanolic extract of Chamaesyce hirta ( L ) Millsp. by using the procedures described above. In FIG. 1 , a chromatogram of the crude methanolic extract of Chamaesyce hirta ( L ) Millsp. is shown. The crude methanolic extract of Chamaesyce hirta ( L ) Millsp. was fractionalized on a TSK Gel ODS 80™(TOSOH) reverse phase column. The particle size of the gel in this column was 5 μm, and the column size was 250×4.6 mm. The mobile phase used was a mixture of H 2 O (A buffer) and absolute ethanol (B buffer) at a flow rate of 0.75 mL/min. The column was sequentially eluted as follows: 0% B for the first 5 minutes; a linear gradient of 0˜15% B for 15 minutes; 15˜50% B for 60 minutes; 50˜100% B for 10 minutes and 100% B for 6 minutes. The detection was performed at a wavelength of 280 nm with a detection sensitivity of 0.01 AUFS. [0000] 3. L929 Cellular Assay [0000] Cell Culture [0029] L929 cells were cultured in Eagle's Minimal Essential Medium (MEM) containing 10% equine serum, 1% P/S and 1% non-essential amino acid. Confluent L929 cells were washed with 2 ml PBS (phosphate-buffered saline) solution and then trypsinized with 1 ml 1×trypsin, followed by resuspending in complete medium. Two hundred microliter of cell suspension was aspirated for cell density counting. The remainder was centrifuged at 1500 rpm for 5 min. The supernatant was removed and the complete medium was added to dilute cells at a concentration of 1.5×10 5 cells/ml. Add 100 μl of cell suspension to each well in 96-well flat-bottomed microtitre plates and incubated for 24 hrs in 5% CO 2 atmosphere at 37° C. incubator. [0000] TNFα Activity Assay [0030] Crude herbal extracts were resuspended in 1×PBS and sterilized with 0.22 μm filters. Varying concentrations of herbal extract were incubated for 1 hr with equal volume of commercial TNFα 0.2 ng/ml. Before the end of the 1 hr pre-incubation, removing the medium from the 24 hr incubated 96-well plate, and added a 50 μl fresh medium containing 4 μg/ml of Actinomycin D into the 96-well plate. Transferred the 50 μl of pre-incubated mixture of herbal extraction and TNFα to the 96-well plate with the medium containing Act D to give the final concentration of Act D (2 μg/ml), TNFα(0.1 ng/ml). The mixture of Act D (2 μg/ml) and TNFα (0.1 ng/ml) were added as positive control and Act D 2 μg/ml only was used as negative control. Alter gently shaking for 24 hrs in 5% CO 2 atmosphere at 37° C. incubator. [0000] Cytotoxicity [0031] The same samples as those for TNFα activity assay were added to the 96-well plate with the medium containing Act D to give the final concentration of Act D 2 μg/ml. Mixed well by gently shaking and then incubated for 24 hrs in 5% CO 2 atmosphere at 37° C. incubator. 50 μl XTT mixture (XTT−1: XTT−2=50:1) was added to each well, and incubated in a CO 2 incubator for 4 hrs. Read with ELISA (enzyme-linked immunosorbent assay) reader at O.D (optical density) 490/630 nm. Calculation of the TNFα Activity Inhibition and Cytotoxicity TNF ⁢   ⁢ α ⁢   ⁢ Inhibition ⁢   ⁢ % = O . D ⁢ . dilut + TNF + Act . ⁢ - O . D ⁢ . TNFa + Act O . D ⁢ . Act ⁢   ⁢ only ⁢ - O . D ⁢ . TNFa + Act × 100 ⁢ % Cytotoxicity ⁢   ⁢ % = O . D ⁢ . dilut . + ActD O . D ⁢ . ActD ⁢   ⁢ only × 100 ⁢ % 4. Quercitrin and Myricitrin Identification (1) Thin-Layer Chromatography [0032] For TLC experiment, precoated plates of silica gel 60F 254 (E. Merck) were used and spotting was done with capillary tubes. The plates were scanned on a UV observed box (Gamag). The solvent system was chloroform:methanol:ethyl acetate/MeOH=20/1.5 for pure quercitrin and ethyl acetate/MeOH=6/1 for pure myricitrin. TLC of the isolated quercitrin and myricitrin showed a single spot with its R f value 0.63 and 0.6 in this solvent system. [0000] (2) LC/MS Spectrum [0033] The atmospheric pressure ionization with ESI mass spectrum of molecular ions was obtained on a LC/MS (Varian). The mobile phase was water/EtOH. Quercitrin Mass: 445 (M+H) + ( FIG. 8 ), myricitrin 461 (M+H) + ( FIG. 9 ). [0000] (3) HPLC Spectrum [0034] The HPLC spectra of quercitrin and myricitrin were obtained. The reference standard was obtained by TSK Gel ODS 80™ (5 μm) TOSOH reverse phase column (4.6×250 mm) using a Shimadu HPLC system with a mobile phase containing ethanol and water. The HPLC analysis of the quercitrin gave a single peak with retention time of 46.3 min ( FIG. 4 ), and retention time of myricitrin was 51.8 min ( FIG. 5 ). The following HPLC condition should be used when carrying out this analysis: Gradient Time (min) B buffer (EtOH) % 0˜5  0  5˜20 0˜15 20˜80 15˜50  80˜90 50˜100 90˜96 100 [0035] A buffer: H 2 O [0036] Flow Rate: 0.75 mL/min [0037] Detection Wavelength: 280 nm [0038] Injection volume: 100 μL [0000] (4) 1 H-NMR Spectrum [0039] The 1 H-NMR spectrum of quercitrin is shown in FIG. 10 . 1 H-NMR (600 MHz, Acetone-d 6 ) δ0.91 (3H, d, J=6.0 Hz, Me rhamnose), 3.31-4.20 (4H, m, sugar protons), 5.52 (1H, d, J=1.2 Hz, H-1″), 6.26 (1H, d, J=1.8 Hz, H-6), 6.47 (1H, d, J=1.8 Hz, H-8), 6.99 (1H, d, J=7.8 Hz, H-5′), 7.40 (1H, dd, J=2.4, 7.8 Hz, H-6′), 7.50 (1H, d, J=2.4 Hz, H-2′). [0040] The 1 H-NMR spectrum of myricitrin is shown in FIG. 11 . 1 H NMR (600 MHz, CD 3 OD) δ 0.96 (3H, d, J=6.0 Hz, Me rhamnose), 3.31-4.20 (4H, m, sugar protons), 5.31 (1H, d, J=1.2 Hz, H-1″), 6.26 (1H, d, J=1.8 Hz, H-6), 6.36 (1H, d, J=2.4 Hz, H-8), 6.95 (2H, s, H-2′ and H-6′). [0000] 5. Anti-Inflammatory Effect of Myricitrin and Quercetin-3-D-glucoside on Rats With Collogen-Induced Arthritis [0041] SD rats of SPF grade were supplied from BioLasco. Prior to performing the study, the animals were accommodated for 4 days after being received. Weighing, blood sampling, measuring the paw volumes and other related records for each animal were established. The rats were immunized and boosted with bovine collagen II-EFA (Incomplete Freund's Adjuvant, from Sigma) to induce arthritis (CIA). The CIA rats were grouped into 6 groups and daily injected with the drug candidates (myricitrin and quercetin-3-D-glucoside respectively). Dexamethasone (0.2 mg) was used as a positive control and 5% ethanol as a negative control. Treatment period was 7 days. Body weight and paw volumes were measured and blood sampling were collected at day 0, 3, 6, 10 and 14. [0042] Six days after the final dosing, all the animals were sacrificed. The affected hind limbs were removed for histological assessment. The parameters of body weights and paw volumes were measured and compared for before, during and after treatment with drug candidates. [0043] Collagen-induced arthritis was found on day 9th after boostering, the volumes of hind paw swelled 2-2.5 times that of normal hind paws. (See FIG. 13-1 in which FIG. 13-1 a shows hind paw before CII-IFA injection. FIG. 13-1 b shows hind paw with collagen-induced arthritis. Swelling and erythema appeared.) The group treated with myricitrin showing decreased percentage, 65.98%, of edema volumes for hind paws after continual treatment for 6 days. On the 3 rd day and 7 th day after treatment stopped, the decreased percentage of edema were 55.95% and 50.93% for myricitrin. (See FIG. 13-2 , in which FIG. 13-2 a shows volumes of left hind paw for group myricitrin. The volume of T0 is before injected CII-IFA, T1 is before treatment, T3 is day 6th of treatment, T4 and T5 are day 3rd and day 7th after administered. FIG. 13-2 b shows different time points of edema percentage comparison with non-treatment volume of paw. T3 is 1−(T3−T1/T1−T0)%, T4 is 1−(T1-T4/T1−T0)% and T5 is 1−(T1-T5/T1−T0)%.). In the group treated with quercetin-3-D-glucoside, it appeared slight decrease percentage of edema volume in the treatment period (8.59%) in comparison with non-treatment. After stop administer day 3rd the decrease percentage was down to 24.93% and increase to 80.47% on day 7th. (See FIG. 13-3 , in which FIG. 13-3 a shows volumes of left hind paw for group quercetin-3-D-glucoside. The volume of T0 is before injected CII-IFA, T1 is before treatment, T3 is day 6th of treatment, T4 and T5 are day 3rd and day 7th after administered. FIG. 13-3 b shows different time points of edema percentage compared with non-treatment volume of paw. T3 is 1−(T3−T1/T1−T0)%, T4 is 1−(T1-T4/T1−T0)% and T5 is 1−(T1-T5/T1−T0)%.) While the group treated with dexamethasone was 28.21% on the 3 rd day and 29.97% on the 7 th day in decreased percentage of edema. (See FIG. 13-4 , in which FIG. 13-4 a shows volumes of left hind paw for group dexamethasone. The volume of T0 is before injected CII-IFA, T1 is before treatment, T3 is day 6th of treatment, T4 and T5 are day 3rd and day 7th after administered. FIG. 13-4 b shows different time points of edema percentage compared with non-treatment volume of paw. T3 is 1−(T3−T1/T1−T0)%, T4 is 1−(T1-T4/T1−T0)% and T5 is 1−(T1-T5/T1−T0)%.) Histopathological changes with loose connective tissues, lymphocytes infiltration around joint, periarticular edema and proliferation of synovial ling cells were observed in all arthritis samples ( FIG. 13-6 to FIG. 13-10 ) but not in normal samples ( FIG. 13-5 ). FIG. 13-5 shows a normal histological slice of joint of non-immune with collagen II. FIG. 13-6 shows a histopathological slice of rats with CIA and treated (IP) with myricitrin, in which proliferation of cell and infiltration of lymphocytes could be observed. FIG. 13-7 shows a histopathological slice of rats with CIA and treated (IP) with quercetin-3-D-glucoside, in which proliferation of synovial ling cell and infiltration of lymphocytes was shown. FIG. 13-8 shows a histopathological slice of rats with CIA and treated (IP) with dexamethasone. Proliferation of synovial ling cell and infiltration of erythrocytes and some lymphocytes could be observed. FIG. 13-9 shows a histopathological slice of rats with CIA and treated (IP) with 5% ethanol. Proliferation of synovial ling cell and infiltration of lymphocytes could be observed. FIG. 13-10 shows a histopathological slice of rats with CIA treated with dexamethasone. Periarticular edema and infiltration of lymphocytes were observed.

The use of flavone derivatives of formula (I) in which R 1 , R 2 , R 3 , R 4 and R 5 independently represent hydrogen, hydroxy or an ester group; R 6 represents hydrogen, hydroxy, an ester group or an O-glycoside group such as O-rhamnose, O-glucoside, O-retinoside or O-xyloside; and

FIELD OF INVENTION [0001] The invention relates to an apparatus and method for measuring local brain water content, perfusional pulsatile changes and the real time derivation of brain stiffness by comparison of perfusional and intracranial pressure tracings. BACKGROUND OF INVENTION [0002] Monitoring intracranial pressure (ICP) in real time in intensive care units has become an established standard of care in guiding physicians in the management of severe head injury. Treatment of head trauma increases pressure on the brain requiring monitoring intracranial pressure. This is particularly true in complicated cases of hydrocephalus as a post-craniotomy adjunct to detect brain swelling and in selected instances of brain infection and stroke. As brain swelling worsens due to the disease process, baseline pressure and waveform changes signal the need to aggressively attempt to reverse the course of the swelling with medications and pulmonary ventilation changes. [0003] Intracranial pressure monitoring is normally performed by inserting a shunt through a hole in the cranium. A ventriculostomy catheter connected to an external pressure transducer is then introduced via the shunt into the brain substance. The shunt may also be used to drain excess fluid from the brain substance. An external pressure transducer provides accurate pressure measurements since a reliable baseline may be established. However, an external pressure transducer requires invasive procedures, risking a patient's health. [0004] More recently, a miniaturized fiberoptic or strain gauge pressure transducer is inserted into the brain substance. The miniaturized transducer greatly reduces the invasiveness of the insertion procedure, but no practical method exists to establish a baseline measurement. This creates accuracy problems since many factors over the course of treatment may shift baseline measurements. Additionally, the ICP sensor and data from it alone do not allow a direct measurement of how edematous or congested the specific region of the brain is. Furthermore, swelling provides a widely ranging pressure change related to age and causes of the swelling. Finally, the ICP sensor alone does not provide a measurement of real time brain stiffness or compliance, a helpful indicator of imminent deterioration risk. [0005] Static measurement may be achieved by magnetic resonance imaging (“MRI”), but this does not provide real time data. Real time information would greatly facilitate the detection of true shunt failure in the management of hydrocephalus. However, since real time measurement cannot be done with internal sensors, shunt failure must be inferred from late presenting clinical deterioration and anatomical changes as seen in imaging studies of the MRI. Additionally, the transport of a critically ill patient to an MRI facility is hazardous. [0006] There is therefore a need for an instrument which may be inserted through a single aperture in the skull for simultaneous and continuous monitoring of both intracranial pressure and cerebral water content. There is another need for an instrument which may continuously measure pulsatile changes, altering apparent water content relating to beat-to-beat tissue perfusion due to cardiac output of blood to the brain. There is a further need for an instrument which provides the continuous measurement of tissue congestion related to venous back pressure from mechanical ventilation. There is another need for an instrument which derives the percent water content of the brain for comparison against normal values. There is yet another need for a system to monitor the more gradual baseline changes in wetness or brain edema of intracellular or extracellular origin related to the disease process. There is another need for an instrument which can simultaneously display the intracranial pressure (ICP) waveform and the pulsatile perfusional or momentary congestion changes of the brain. There is still another need for an apparatus and method for comparing the differences in lagtime between the ICP and perfusional waveforms, from which a realtime measurement of brain stiffness or compliance is derived. SUMMARY OF THE INVENTION [0007] These needs may be addressed by the present invention which is embodied in one aspect of the invention which is a probe for measuring tissue water content in a region of interest in the brain. The probe has an implantable tissue water content sensor having two plates with a proximal and distal end. The two plates are separated by a dielectric material and the distal end is implantable in brain tissue. An impedance matching circuit is coupled to the proximal end of one of the plates. A first output terminal is coupled to the matching circuit resistor and a second output terminal is coupled to one of the plates. A remotely positioned frequency spectrum analyzer receives an output signal from the first and second output terminals. A digital computer has a display, the digital computer having an input coupled to the output signal from the water content probe and the spectrum analyzer, the computer programmed to display the resonant frequency of the sensor indicative of water content in the brain tissue. [0008] Another aspect of the present invention is a method of measuring tissue water content in a selected region of interest in the brain. A capacitive sensor having two plates outside the selected region of interest is calibrated and the resonant frequency of the sensor in air is determined. The capacitive sensor is calibrated in a mixture of water and NaCl. The resonant frequency of the sensor in the mixture is determined. A linear baseline frequency in relation to water content based on the resonant frequencies of the sensor in air and the mixture is established. The capacitive probe is implanted through a skull aperture such that the capacitive plates are exposed to the brain cortex and subjacent white matter. Interrogatory frequency scanning by a spectrum analyzer coupled to the sensor is produced to determine the center point of resonance by passage of the signal. True tissue water content is approximated by curve-fitting the frequency of resonance with the baseline frequency. [0009] Another aspect of the present invention is a method of deriving beat-to-beat perfusional and congestion changes in brain tissue. The method includes inserting a water content probe having two conductive plates and a dielectric in the brain tissue. Signals at different frequencies on the water content probe are sent. A standing wave ratio at different frequencies is determined. A water content change tracing which fluctuates with cardiac output pulsatile perfusion of the tissue is then determined. [0010] Another aspect of the present invention is a method of deriving realtime compliance or stiffness of brain tissue. The intracranial pressure of the brain tissue is measured. An intracranial waveform from the measurements of the intracranial pressure is then plotted. The pulsatile congestion changes in water content of the brain tissue is measured. A pulsatile congestion change waveform is plotted from the measurements of the pulsatile congestion change. The waveforms of intracranial pressure and the pulsatile congestion change in water content on a computer are simultaneously plotted. The stiffness of the brain is then determined from the simultaneous plotting. [0011] Another aspect of the present invention is a probe for measuring tissue water content in a region of interest in the brain. The probe has an implantable tissue water content sensor having two plates with a proximal and distal end. The two plates are separated by a dielectric material and the distal end is implantable in brain tissue. A signal transmitting circuit is coupled to the proximal end of one of the plates. A signal receiver is provided. A remotely positioned frequency spectrum analyzer is coupled to the signal receiver. A digital computer is provided having a display and an input which is coupled to the output signal from the water content probe and the spectrum analyzer. The computer is programmed to display the resonant frequency of the sensor indicative of water content in the brain tissue [0012] It is to be understood that both the foregoing general description and the following detailed description are not limiting but are intended to provide further explanation of the invention claimed. The accompanying drawings, which are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the method and system of the invention. Together with the description, the drawings serve to explain the principles of the invention. BRIEF DESCRIPTION OF DRAWINGS [0013] This invention is pointed out with particularity in the appended claims. However, other objects and advantages together with the operation of the invention may be better understood by reference to the following illustrations, wherein: [0014] FIG. 1 is a perspective view of a brain stiffness probe according to an embodiment of the present invention. [0015] FIG. 2 is a partial cutaway view depicting the probe in FIG. 1 inserted through an aperture in the skull such that it is exposed to direct contact with brain tissue. [0016] FIG. 3 is a block diagram with the probe components and remotely placed measuring equipment for both the water content sensor component and intracranial pressure component according to one embodiment of the present invention. [0017] FIG. 4A - FIG. 4D are frequency resonance curves and calibration and measurement of tissue water content taken using a system according to the present invention. [0018] FIG. 5 is a waveform diagram showing pulsatile changes in microscopic center frequency shifts in the water content probe according to the present invention due to perfusion of the brain by cardiac pulsatile output. [0019] FIG. 6 is a block diagram of a wireless implementation of a water content probe according to the present invention. [0020] FIG. 7A-7B are waveform diagrams which show the phase or lagtime relationship between the pressure waveform and perfusional waveform derived from the water content component of the combined probe according to the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT [0021] While the present invention is capable of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiment illustrated. [0022] In accord with one embodiment of the invention, a combined probe 10 for measuring brain wetness and intracranial pressure is shown in FIG. 1 . The probe 10 has a water content sensor 11 which has two conductive plates 12 and 14 on opposite sides of a printed circuit board (PCB) substrate 16 . The conductive plates 12 and 14 are silver in the preferred embodiment but any suitable conductor material may be used. The substrate 16 in the preferred embodiment measures 5 cm in length, 2 mm in width, and 0.5 mm in depth. The probe 10 has a proximal end 18 and a distal end 20 . Multiple holes 22 extend across the PCB substrate 16 . The holes 22 increase sensitivity to real time pulsatile perfusional changes in tissue as they increase the surface area in contact with the brain tissue. The proximal end 18 has a surface mount resistor 24 on one side. A coaxial cable 26 has a core conductor member 28 and a shielding conductor 30 which is circumferentially located around the core member 28 . [0023] The surface mount resistor 24 is coupled between the proximal end 18 and one end of the coaxial cable 26 . The surface mount resistor 24 provides impedance matching between the core 28 of the coaxial cable 26 and the plate 12 . The impedance matching provided by the surface mount resistor 24 and the cable 26 is employed to achieve noise immunity in the cable 26 and allow the analysis electronics to be located at a distance from the water content sensor 11 . Other types of impedance matching circuits such as a balanced antenna approach may be used as well. The plate 14 is connected directly to the shielding conductor 30 of the coaxial cable 26 . The other end of the coaxial cable 26 is connected via an adapter 32 to a controller unit 34 . In this sample, the adapter 32 is a PL250 type which minimizes signal loss to the cable 26 . [0024] The water content sensor 11 is inserted through a plastic bolt 36 via an aperture 38 . The plastic bolt 36 has a pair of hex nuts 40 and 42 which are mounted on a main body section 44 . The main body 44 has an exterior surface with threads. A lug nut 46 is coupled to the main body 44 and has corresponding interior threads. The lug nut 46 may be rotated on the main body 44 and provides a connection for the cable 26 . [0025] The probe 10 is inserted to a depth in brain tissue up to the plastic bolt 36 via the aperture. The hex nuts 40 and 42 and the lug nut 46 are tightened on the main body 44 of the bolt 36 to provide a seal and to allow the plastic bolt 36 to be positioned and held in the aperture 38 . The bolt 36 is designed such that the surface mount resistor 24 lies about 1 mm above the surface of the brain, placing nearly the full length of the plates 12 and 14 in the brain tissue. Since the water of the brain bears a moderate salinity (typically 130-150 mEq Na+ per 1000 ml), an extremely thin-sputtered layer of insulation 50 insulates the electrical plates 12 and 14 from direct tissue contact. The insulation layer 50 is Teflon in the preferred embodiment, but any type of insulation may be used. The insulation layer 50 allows the point of resonance of the water content sensor 11 to be precisely measurable. The configuration of the capacitive plates 12 and 14 may be used in a tubular configuration to allow a silicone external ventricular drain through the lumen. In such a configuration, the electrically conductive plate surfaces are located on the length of the tube on opposite hemispheres to create a similar capacitive effect. [0026] FIG. 2 shows a cutaway view of a head 60 with a brain 62 shown through the frontal lobes as seen by a typical MRI. The brain 62 is encased by a cranium 64 . The containment of the cranium 64 creates pressure on the brain 62 which may be excessive due to fluid buildup. A skull aperture 66 (or burr hole) is created in the cranium 64 after a scalp incision. This routine procedure in the intensive care unit would normally be followed by the introduction of an ICP sensor or ventriculostomy catheter as is presently known. [0027] The plastic ventriculostomy bolt 36 in the preferred embodiment is commercially available through Codman and Shurtleff Incorporated, Raynham, Mass. The plastic bolt 36 is tapped and threaded snugly into the cranium 64 . The water content sensor 11 is passed through the bolt 36 to a depth such that the sensing capacitive plates 12 and 14 are exposed to cortex and white matter of the brain 62 . The plastic bolt 36 provides stable fixation of electrical connections and prevents movement of the sensor 11 in the brain 62 by secure fixation at the skull aperture 66 (burr hole). [0028] An intra cranial pressure (“ICP”) sensor 70 passes through the bolt 36 into the subjacent cortical tissue of the brain 62 . The ICP sensor 70 is an electrical strain gauge type and measures changes in resistance due to pressure. Alternatively, any implantable pressure sensor such as a fiber optic sensor may be used. A fiber optic sensor has lasers coupled to dual fiber optic cables. A diaphragm is coupled to the end of the fiber optic cables and distorts light in reaction to pressure, producing changes in either light amplitude or frequency. In other cases, an external strain gauge which is coupled via tubing to a ventriculostomy catheter or a cranial bolt may be used to measure pressure. [0029] The output voltage of the ICP sensor 70 is carried by a cable 72 . The strain gauge ICP sensor 70 in this example is commercially available from Codman and Shurtleff Incorporated, Raynham, Mass. but any appropriate pressure sensor may be used. The ICP sensor 70 may be inserted separately from the bolt 36 and/or inserted at a separate site on the cranium if desired. This is to be avoided in most cases, but certain circumstances may require the separate insertion of the ICP sensor 70 and the water content sensor 11 . [0030] The respective wiring connections to and from the water content sensor 11 and the ICP sensor 70 are coupled to the controller unit 34 which is at a remote location. Alternatively, the cables may be connected to a signal transmitter if it is desired to eliminate the cables. The technique of positioning the combined sensors is identical to the routine insertion of a ventriculostomy catheter for monitoring and carries with it the same acceptably low risks. [0031] FIG. 3 is a block diagram of the control unit 34 of the combined ICP-water content probe 10 . The ICP sensor 70 is a strain-gauge type which has a wheatstone bridge 74 of standard configuration having a pressure transducer 76 and three resistors 78 , 80 and 82 . The voltage of the bridge 74 changes in accordance to pressure changes on the pressure transducer 76 . The output voltage of the bridge 74 represents the sensed pressure on transducer 76 and is coupled to the input of an analog to digital convertor 84 via the cable 72 . The output of the analog to digital convertor 84 is coupled to a digital computer 86 . [0032] The water content sensor 11 is coupled via the coaxial cable 26 to an input of a spectrum analyzer 88 . The spectrum analyzer 88 in the preferred embodiment is an AEA-Tempo 150-525 Analyst manufactured by Tempo Research of Vista, Calif. The spectrum analyzer 88 sweeps an interrogating frequency from 150 MHZ to 550 MHZ every 2 seconds to the water content sensor 11 in the preferred embodiment. The frequency spectrum for measuring brain water content without interference from other sources is optimally measured between 400 and 600 MHZ. However, other ranges may be useful depending on the probe length. [0033] The direct output from the spectrum analyzer 88 is coupled to the digital computer 86 and a second output is coupled to an analog to digital convertor 90 . This allows display of the resonant frequency of the water content sensor 11 determined from the direct output, as well as heart beat to heart beat changes in frequency and standing wave ratio (SWR) from the digital to analog converter 90 . The outputs from the spectrum analyzer 88 and the digital to analog convertor 90 are plotted on a display 92 . The display 92 is preferably a high resolution monitor but any display device may be used. [0034] The digital computer 86 contains software necessary to simultaneously display the pulsatile waveform outputs from the ICP sensor 70 and the water content probe 11 on the display 92 . As will be explained below, the brain water content and blood congestion alter the resonant frequency of the water content probe 11 and provides an indication of the real time read out of apparent tissue water content and the stiffness of the brain 62 which is independent of baseline water content or pressure. [0035] FIGS. 4A-4D illustrates the process of probe calibration and water content determination of brain tissue which is displayed using the software on the digital computer 86 in conjunction with the display 92 . The water content sensed by the water content sensor 11 of the probe 10 in FIGS. 1 and 2 is indicative of the effect of the surrounding tissue dielectric on the speed of transmission of the interrogating signal through the plates 12 and 14 . Similar in concept to time domain reflectometry and familiar to those skilled in the art, the spectrum analyzer 88 will display a resonant frequency when the water content sensor 11 is placed in tissue. This resonance is a function of plate capacitance of the plates 12 and 14 (most strongly affected by probe length in this configuration) and the adjacent dielectric of the material of the substrate 16 . The PCB dielectric material 16 between the plates 12 and 14 and the extremely thin-sputtered layer 50 have dielectric constants near air (dielectric of 1). In contrast, the brain is normally about 70% water. As the dielectric of H2O is 80, the tissue water content overwhelmingly determines the resonant frequency measured from the water content sensor 11 . [0036] FIG. 4A shows the output plot of the spectrum analyzer 88 displayed by the digital computer 86 when the water content sensor 11 is entirely exposed to air. Since no significant water content related dielectric slows the signal in air, the resonant frequency of the water content sensor 11 is 440 MHZ. FIG. 4B shows the output plot when the water content sensor 11 is inserted in a 100% normal saline and water compound (simulating brain water and salinity). The resonant frequency of the water content sensor 11 has decreased to 167 MHZ as shown in FIG. 4B . This reduction is due to the overwhelming dielectric effect of the surrounding water with its high dielectric constant. [0037] FIG. 4C shows the sharp resonant curve of the output of the water content sensor 11 when placed in the brain tissue 62 as shown in FIG. 2 . The resonant frequency is 307 MHZ in FIG. 4C . The water content of the brain tissue 62 is proportional to the resonant frequency. The different resonant frequencies sensed by the sensor 11 in differing conditions of water content may be plotted. FIG. 4D shows the linearity of a typical output curve from the water content sensor 11 from submersing the sensor 11 in water as in FIG. 4A to full exposure in air as in FIG. 4B . By testing the water content sensor 11 in tissue utilizing dry and wet weight water content determinations, the linear range of clinical significance from 65% (very dehydrated brain) to 80% (very edematous brain) may be tested and provides a measurement standard for water content determination. [0038] The measurable accuracy of the water content sensor 11 is up to 0.1% of water content change. In clinical use, however, the absolute local water content determination is not as useful as the trending of water content of the brain tissue over the course in the intensive care unit against a baseline measurement. The long term trends are more useful data since insertion of the water content sensor 11 , as any probe, into the brain 62 , causes a temporary injury edema which develops about the sensor 11 and artificially increases the baseline water content in the region. Additionally, effects of local minor accumulation of a non-flowing blood clot against the sensor plates 12 and 14 or incomplete passage to full depth of the plates 12 and 14 will offset the true water content baseline. Despite these considerations, the baseline measurement is used as a control against the course of illness and therapeutic intervention with dehydrating drugs such as furosemide and mannitol or ventilator changes provide a real time feedback of impact of the physician's regimen on the patient. [0039] When the baseline water content is plotted over hours of time on a computer such as the computer 86 , gradual shifts in the water content may be analyzed. For example, the initial shift in water content represents the initial placement edema and its resolution. The longer term shift in water content may represent the trend of brain swelling in the region of monitoring, edema due to head injury, or the effects of therapy. Alternatively, the changes in resonant frequency may also be logged using a spectrum/frequency analyzer such as a Model HP8568A manufactured by Hewlett-Packard. However, much smaller changes of significance to the course of the illness may be measured from heart beat to heart beat as will be explained below. Thus, the water content sensor 11 may be used in isolation without the associated intracranial pressure sensor 70 , yielding profitable data for the patient. [0040] FIG. 5 shows a pulsatile baseline 500 obtained from minute apparent water content change. Either one of two techniques may be used to obtain the water content change on a heart beat to heart beat basis. The first technique involves use of the frequencies around the resonant frequency. When the spectrum analyzer 88 is employed to identify the standing wave ratio (“SWR”) at resonance, a properly placed water content sensor 11 will show an SWR of 1.0. The frequency of resonance relates to the water content which is 307 MHZ in FIG. 4D . [0041] However, if the frequency just to the right of the resonant point in FIG. 4D is selected where maximum change in SWR occurs per unit frequency change, typically an SWR of about 1.15, the beat-to-beat change of SWR may be plotted. The beat to beat SWR changes thus correlates to the local increased water content sensed by the water content sensor 11 which is due to transient increased tissue congestion and arteriolar dilation due to blood flow. An undulating waveform 502 as a function of time is shown in FIG. 5 . The undulating waveform 502 is measured from the water content sensor 11 as a function of the change in SWR from heart beat to heart beat. A slower baseline undulation relates to back pressure on the venous side of the brain from positive pressure ventilation of the patient or may be evoked by transient jugular vein compression (termed the Queckenstedt maneuver). [0042] Alternatively, the beat-to-beat effect may be measured by tracking the center frequency of resonance deviation when the water content sensor 11 in FIGS. 1 and 2 is viewed as the variable component of a simple LC resonant circuit 100 as shown in FIG. 6 . The sensor 11 is coupled to an inductor 102 . The sensor 11 and the inductor 102 may thus be integrated in an implanted sensor unit 104 . A second inductor 106 is coupled to the processing circuitry which includes a signal generator and resonant frequency measurement device as explained above. Since the value of the first inductor 102 is fixed, the resonant frequency will shift as a function of water content of the tissue surrounding the sensor unit 104 . The resonant frequency is measured wirelessly by sensing magnetic field energy from the second inductor 106 and the signal generator. [0043] A significant advantage of this approach is that beat-to-beat pulsatile changes and baseline water content may be measured wirelessly using a spectrum analyzer pick-up circuit across the scalp from a wholly implanted resonant circuit. This technique allows long term, wireless monitoring of a region of interest over months to years for determining optimal compliance and control of hydrocephalus in patients treated by a ventriculoperitoneal shunting procedure. [0044] With reference to FIGS. 1 and 2 , when the intracranial pressure (ICP) waveform is plotted simultaneously with the pulsatile water content waveform derived from the two techniques described above, a phase relationship between the waveforms is seen. FIG. 7A shows a simultaneous plot of pressure 600 versus a pulsatile water content plot 602 . The pressure plot 600 precedes pulsatile congestion as sensed by the water content probe plot 602 . This indicates that peak vascular congestion lags peak pressure. FIG. 7A depicts the phase relationship plotted of a healthy, normal brain. In FIG. 7A , brain stiffness is within acceptable levels and thus the phase of beat to beat water content resonant frequency is phase shifted from the pressure changes by 115 degrees. [0045] In contrast, FIG. 7B shows the pressure and water content plots 600 and 602 superimposed on each other in an example of worsening brain compliance or stiffness. The beat to beat water content resonant frequency is phase shifted from the pressure changes by 68 degrees. This relationship is also demonstrated by a combined ICP-blood flow probe such as when monitoring a patient with a thermal probe as described in U.S. Pat. No. 4,739,771 to the same inventors and incorporated by reference herein. In a normal, relaxed brain, the peak flow or vascular congestion may lag substantially, especially in a child with an open antereor fontanel. As the brain becomes progressively swollen with brain edema in head injury the lag narrows until the two waveforms are essentially co-incidental. Similarly, poor compliance in a patient with shunt failure will show the pattern of narrowing of lag time. The relationship can also be measured in real time as a function of phase lag adjusted for frequency (heart beat), akin to phase lag plotting in current phase compared to voltage phase in inductive circuits. Thus, the relationship by lag in seconds or phase angle adjusted for frequency provides a measure of brain stiffness which is independent of transducer amplitude, accuracy or stability, allowing a frequency domain relationship applicable to long term monitoring including implants. [0046] It will be apparent to those skilled in the art that the disclosed measurement method and apparatus described above may be modified in numerous ways and assume many embodiments other than the preferred forms specifically set out and described above. Alternatives to the capacitive water content sensing technology include time domain reflectometry and square-wave frequency based sensors as well as fiberoptic sensors. The time domain reflectometry views the sensing components as a model transmission line. The reflection of a signal is measured as a function of water content. The square wave frequency based sensor uses a broad range of frequencies to determine water content as a function of the frequencies observed. The proper interpretation of the square wave frequency signals requires the appropriate circuitry. The fiberoptic sensor uses a light signal of a certain wavelength which is propagated down an implanted fiber. An optical grating is used to determine reflection of the light signal which is a function of the water content. [0047] The pulsatile flow relationship to the ICP waveform can be derived by use of transducers such as thermistors (as described in the author's cited patent), or other heat clearance transducers as well as by transcranial impedance measurement and local tissue laser Doppler technique. The transcranial impedance measurement is performed by placing an ohmmeter on the head and measuring the signals at high frequency. An alternate impedance measurement may be used using a four probe method. Two impedance probes measure the output while two probes input the signal. The laser Doppler technique uses a laser to send a signal to the tissue of interest. The shift in Doppler frequency is measured to determine the water content. [0048] An antenna sensor may be used for the water content sensor instead of the capacitive approach explained above. The entirety of the circuitry which includes the implanted circuit with an antenna to sense the water content in the tissue and a transmitter can be reduced to an integrated circuit as part of an implant or integrated onto the probe itself, allowing transcranial, wireless interrogation. The present invention is not limited by the foregoing descriptions but is intended to cover all modifications and variations that come within the scope of the spirit of the invention and the claims that follow.

A method and system to determine brain stiffness is disclosed. A probe to measure tissue water content is inserted through an aperture (burr hole) in the cranium into brain tissue. The probe has two electrically separated plate conductors with a dielectric which forms a capacitor plane. One conductor has a surface mount resistor to allow exact impedance matching to the core of a coaxial cable. The other conductor attaches electrically to the shield of the coaxial cable. The probe is stabilized in the brain tissue through a plastic ventriculostomy bolt which has been secured by screw tapping into the cranium. The coaxial cable connects to a spectrum analyzer. Brain water content and blood congestion alter the resonant frequency of the probe, allowing a realtime readout of apparent tissue water content. By monitoring the momentary shift in center resonant frequency or, alternatively, the standing wave ratio slightly off resonant frequency, a beat-to-beat pulsatile waveform is derived relating to the perfusion of the brain. A strain gauge intracranial pressure sensor (ICP) is separately affixed through the bolt and adjacent to the water content probe. By comparing the phase angle or lag time difference between the pressure tracing and the perfusion tracing, a realtime measurement of organ stiffness or compliance is derived.

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2015-0090290, filed on Jun. 25, 2015 in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. TECHNICAL FIELD [0002] The present inventive concept relates to a semiconductor device and a method of fabricating the same. DISCUSSION OF RELATED ART [0003] Multigate transistors have been suggested. The multigate transistors are easy to scale down, securing transistor performances. Without the increase of gate length of the multigate transistors, current control capability may be increased and short channel effects (SCE) may be suppressed. SUMMARY [0004] According to an exemplary embodiment of the present inventive concept, a semiconductor device is provided as follows. A first fin-type pattern is disposed on a substrate. A first field insulating film is adjacent to a sidewall of the first fin-type pattern. A second field insulating film is adjacent to a sidewall of the first field insulating film. The first field insulating film is interposed between the first fin-type pattern and the second field insulating film. The second field insulating film comprises a first region and a second region. The first region is closer to the sidewall of the first field insulating film. A height from a bottom of the second field insulating film to an upper surface of the second region is larger than a height from the bottom of the second field insulating film to an upper surface of the first region. [0005] According to an exemplary embodiment of the present inventive concept, a semiconductor device is provided as follows. A first and a second fin-type patterns are spaced from each other. A first trench is disposed between the first and the second fin-type patterns. A first field insulating film having a recess is disposed in the first trench. A second field insulating film is disposed in the recess. [0006] According to an exemplary embodiment of the present inventive concept, a semiconductor device is provided as follows. A first trench is disposed in a substrate. A first field insulating film is disposed in the first trench. A second trench penetrates the first field insulating film. A bottom surface of the second trench is lower than a bottom surface of the first trench. A second field insulating film is disposed in the second trench. A recess is formed within the second field insulating film. A third field insulating film is disposed in the recess. An upper surface of the third field insulating film is higher than an upper surface of an uppermost portion of the second field insulating film. [0007] According to an exemplary embodiment of the present inventive concept, a method of fabricating a semiconductor device is provided as follows. A first trench and a fin-type pattern are formed, and the fin-type pattern is adjacent to the first trench. A first field insulating film fills the first trench. A second trench is formed within the first trench by partially etching the first field insulating film. A bottom surface of the second trench is lower than a bottom surface of the first trench. A second field insulating film is formed in the second trench. The first and the second field insulating films are simultaneously etched to partially expose the fin type pattern. After the simultaneous etching of the first and the second field insulating films, an upper surface of the second field insulating film is formed higher than the first field insulating film due to a difference in etch selectivity. [0008] According to an exemplary embodiment of the present inventive concept, a method of fabricating a semiconductor device is provided as follows. First and second fin-type active patterns are formed on a substrate. A first preliminary field insulating film, a second preliminary field insulating film, and a third preliminary field insulating film are formed in a first region between the first and the second fin-type active patterns. Upper surfaces of the first, the second and the third preliminary field insulating films and upper surfaces of the first and the second fin-type active patterns are substantially coplanar with each other. The third preliminary field insulating film is interposed between the first and the second preliminary field insulating films. A bottom surface of the third preliminary field insulating film is lower than bottom surfaces of the first and the second preliminary field insulating films. A first etching process is performed at a first etch rate on the third preliminary field insulating film to form a third field insulating film. An upper surface of the third field insulating film is lower than the upper surfaces of the first and the second fin-type active patterns. A second etching process is performed at a second etch rate on the first and the second preliminary field insulating films to form first and second field insulating films so that upper surfaces of the first and the second field insulating films are lower than the upper surface of the third field insulating film. The first etching process and the second etching process are simultaneously performed and the first etch rate is smaller than the second etch rate. BRIEF DESCRIPTION OF DRAWINGS [0009] These and other features of the inventive concept will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings of which: [0010] FIG. 1 is a layout diagram of a semiconductor device according to an exemplary embodiment of the present inventive concept; [0011] FIG. 2 is a cross sectional view taken along line A-A′ of FIG. 1 ; [0012] FIG. 3 is a cross sectional view taken along line B-B′ of FIG. 1 ; [0013] FIG. 4 is a cross sectional view taken along line C-C′ of FIG. 1 ; [0014] FIG. 5 is a cross sectional view of a semiconductor device according to an exemplary embodiment of the present inventive concept; [0015] FIGS. 6 and 7 are cross sectional views of a semiconductor device according to an exemplary embodiment of the present inventive concept; [0016] FIG. 8 is a cross sectional view of a semiconductor device according to an exemplary embodiment of the present inventive concept; [0017] FIG. 9 is a cross sectional view of a semiconductor device according to an exemplary embodiment of the present inventive concept; [0018] FIG. 10 is a cross sectional view of a semiconductor device according to an exemplary embodiment of the present inventive concept; [0019] FIG. 11 is a block diagram of a system-on-a-chip (SoC) system comprising a semiconductor device according to an exemplary embodiment of the present inventive concept; [0020] FIG. 12 is a block diagram of an electronic system comprising a semiconductor device according to an exemplary embodiment of the present inventive concept; [0021] FIGS. 13 to 15 illustrate exemplary semiconductor systems including a semiconductor device according to an exemplary embodiment of the present inventive concept; [0022] FIGS. 16 to 19 show a method of fabricating a semiconductor device according to an exemplary embodiment of the present inventive concept; [0023] FIGS. 20 and 21 show a method of fabricating a semiconductor device according to an exemplary embodiment of the present inventive concept; and [0024] FIG. 22 shows a method of fabricating a semiconductor device according to an exemplary embodiment of the present inventive concept. [0025] Although corresponding plan views and/or perspective views of some cross-sectional view(s) may not be shown, the cross-sectional view(s) of device structures illustrated herein provide support for a plurality of device structures that extend along two different directions as would be illustrated in a plan view, and/or in three different directions as would be illustrated in a perspective view. The two different directions may or may not be orthogonal to each other. The three different directions may include a third direction that may be orthogonal to the two different directions. The plurality of device structures may be integrated in a same electronic device. For example, when a device structure (e.g., a memory cell structure or a transistor structure) is illustrated in a cross-sectional view, an electronic device may include a plurality of the device structures (e.g., memory cell structures or transistor structures), as would be illustrated by a plan view of the electronic device. The plurality of device structures may be arranged in an array and/or in a two-dimensional pattern. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS [0026] Exemplary embodiments of the inventive concept will be described below in detail with reference to the accompanying drawings. However, the inventive concept may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the thickness of layers and regions may be exaggerated for clarity. It will also be understood that when an element is referred to as being “on” another element or substrate, it may be directly on the other element or substrate, or intervening layers may also be present. It will also be understood that when an element is referred to as being “coupled to” or “connected to” another element, it may be directly coupled to or connected to the other element, or intervening elements may also be present. Like reference numerals may refer to the like elements throughout the specification and drawings. [0027] Hereinbelow, a semiconductor device according to an exemplary embodiment will be explained with reference to FIGS. 1 to 4 . [0028] FIG. 1 is a layout diagram of a semiconductor device 1 according to an exemplary embodiment, and FIG. 2 is a cross sectional view taken along line A-A′ of FIG. 1 . FIG. 3 is a cross sectional view taken along line B-B′ of FIG. 1 , and FIG. 4 is a cross sectional view taken along line C-C′ of FIG. 1 . [0029] Referring to FIGS. 1 to 4 , the semiconductor device 1 may include a first to a fourth fin-type patterns F 1 -F 4 , a first to a fourth shallow trenches ST 1 -ST 4 , a deep trench DT, a first field insulating film 120 , a second field insulating film 130 and a first gate electrode 210 . [0030] The first to the fourth fin-type patterns F 1 -F 4 may extend in a first direction X 1 , respectively. The first to the fourth fin-type patterns F 1 -F 4 may be spaced from each other in a second direction Y 1 . The third shallow trench ST 3 may be formed between the first fin-type pattern F 1 and the second fin-type pattern F 2 (or 110 ). The first shallow trench ST 1 , the second shallow trench ST 2 and the deep trench DT may be formed between the second fin-type pattern F 2 (or 110 ) and the third fin-type pattern F 3 . The fourth shallow trench ST 4 may be formed between the third fin-type pattern F 3 and the fourth fin-type pattern F 4 . [0031] The first fin-type pattern F 1 and the second fin-type pattern F 2 (or 110 ) may be formed in a first active region ACT 1 of a substrate 100 . The third fin-type pattern F 3 and the fourth fin-type pattern F 4 may be formed in a second active region ACT 2 of the substrate 100 . [0032] As illustrated in FIG. 1 , dual fin structures having the deep trench DT in the middle may be provided, although exemplary embodiments are not limited thereto. Accordingly, single fin structures may be formed on both sides of the deep trench DT, or only one side may be the single fin structure. Further, a multi fin structure having a plurality of fins may be formed instead of the dual fin structure. [0033] The substrate 100 may be a silicon substrate, a bulk silicon or a silicon-on-insulator (SOI), for example. In an exemplary embodiment, the substrate 100 may include a semiconductor material such as germanium, or a compound semiconductor material such as a IV-IV group compound semiconductor or a III-V group compound semiconductor, for example. In an exemplary embodiment, the substrate 100 may be a base substrate having an epitaxial layer formed thereon. [0034] In an exemplary embodiment, the IV-IV group compound semiconductor may be a binary compound or a ternary compound including at least two or more of carbon (C), silicon (Si), germanium (Ge), and tin (Sn). In an exemplary embodiment, the IV-IV group compound semiconductor of the binary or the ternary compound may be doped with a IV group element. [0035] In an exemplary embodiment, the III-V group compound semiconductor may be a binary compound, a ternary compound and a quaternary compound which may include a III group element including aluminum (Al), gallium (Ga), or indium (In) and a V group element including phosphorus (P), arsenic (As) or antimony (Sb). [0036] For the convenience of a description, it is assumed that the first to the fourth fin-type patterns F 1 -F 4 are silicon fin-type active patterns which include silicon. [0037] As illustrated in FIG. 1 , the first to the fourth fin-type patterns F 1 -F 4 may be in a rectangular shape, but the present inventive concept is not limited thereto. The first to the fourth fin-type patterns F 1 -F 4 in the rectangular shape may include a long side extended in the first direction X 1 and a short side extended in the second direction Y 1 . [0038] The second fin-type pattern 110 may include a first portion 110 - 1 and a second portion 110 - 2 . The second portion 110 - 2 of the second fin-type pattern may be disposed on both sides of the first portion 110 - 1 of the second fin-type pattern in the first direction X 1 . [0039] The second fin-type pattern 110 may include, on both sides, a first side surface and a second side surface opposed to each other in the second direction Y 1 . The first shallow trench ST 1 may be in contact with the first side surface, and the third shallow trench ST 3 may be in contact with the second side surface. For example, the second fin-type pattern 110 may be defined by the first shallow trench ST 1 and the third shallow trench ST 3 . [0040] The first shallow trench ST 1 may be formed to be in contact with the first side surface of the second fin-type pattern 110 . For example, a bottom surface of the first shallow trench ST 1 may be an upper surface of the substrate 100 , and one side surface of the first shallow trench ST 1 may be the first side surface of the second fin-type pattern 110 . A first portion 120 a of the first field insulating film may be formed in the first shallow trench ST 1 . A third portion 120 c of the first field insulating film may be formed in the third shallow trench ST 3 . [0041] The third shallow trench ST 3 may be formed to be in contact with the second side surface of the second fin-type pattern 110 . For example, a bottom surface of the third shallow trench ST 3 may be the upper surface of the substrate 100 , and one side surface of the third shallow trench ST 3 may be the second side surface of the second fin-type pattern 110 . Further, the other side surface of the third shallow trench ST 3 may be the one side surface of the first fin-type pattern F 1 . [0042] The first shallow trench ST 1 may be in contact with the second fin-type pattern 110 and may also contact the deep trench DT. That is, the first shallow trench ST 1 may contact the deep trench DT at a side opposite to the side contacting the second fin-type pattern 110 . [0043] The third fin-type pattern F 3 may include, on both sides, a first side surface and a second side surface opposed to each other in the second direction Y 1 . The first side surface of the third fin-type pattern F 3 may face the first side surface of the second fin-type pattern F 2 (or 110 ). The second shallow trench ST 2 may be in contact with the first side surface of the third fin-type pattern F 3 , and the fourth shallow trench ST 4 may be in contact with the second side surface of the third fin-type pattern F 3 . For example, the third fin-type pattern F 3 may be defined by the second shallow trench ST 2 and the fourth shallow trench ST 4 . [0044] The second shallow trench ST 2 may be formed to be in contact with the first side surface of the third fin-type pattern F 3 . For example, a bottom surface of the second shallow trench ST 2 may be the upper surface of the substrate 100 , and one side surface of the second shallow trench ST 2 may be the first side surface of the third fin-type pattern F 3 . A second portion 120 b of the first field insulating film may be formed in the second shallow trench ST 2 . A fourth portion 120 d of the first field insulating film may be formed in the fourth shallow trench ST 4 . [0045] The fourth shallow trench ST 4 may be formed to be in contact with the second side surface of the third fin-type pattern F 3 . For example, a bottom surface of the fourth shallow trench ST 4 may be the upper surface of the substrate 100 , and one side surface of the fourth shallow trench ST 4 may be the second side surface of the third fin-type pattern F 3 . Further, the other side surface of the fourth shallow trench ST 4 may be one side surface of the fourth fin-type pattern F 4 . [0046] The second shallow trench ST 2 may be in contact with the third fin-type pattern F 3 and may also be in contact with the deep trench DT. For example, the second shallow trench ST 2 may be in contact with the deep trench DT at a side opposite to the side contacting the third fin-type pattern F 3 . For example, the first shallow trench ST 1 and the second shallow trench ST 2 may be formed on both sides of the deep trench DT. [0047] The deep trench DT may be in contact with the first shallow trench ST 1 and the second shallow trench ST 2 . The bottom surface of the deep trench DT may be connected with the bottom surfaces of the first shallow trench ST 1 and the second shallow trench ST 2 . The bottom surfaces of the first shallow trench ST 1 and the second shallow trench ST 2 may each be higher than the bottom surface of the deep trench DT. Accordingly, stepped portions may be formed between the bottom surface of the deep trench DT, and the bottom surfaces of the first shallow trench ST 1 and the second shallow trench ST 2 . [0048] Accordingly, the first shallow trench ST 1 and the third shallow trench ST 3 may define the second fin-type pattern 110 , and the second shallow trench ST 2 and the fourth shallow trench ST 4 may define the third fin-type pattern F 3 . The deep trench DT may define the first active region ACT 1 and the second active region ACT 2 . For example, the first active region ACT 1 and the second active region ACT 2 may be divided from each other with reference to the deep trench DT. A second field insulating film 130 may be formed in the deep trench DT. [0049] A first trench T 1 may be defined by the first side surface of the second fin-type pattern F 2 (or 110 ) and the first side surface of the third fin-type pattern F 3 . The first field insulating film 120 may be formed in the first trench T 1 . Further, a second trench T 2 may penetrate the first trench T 1 so that a bottom surface of the second trench T 2 is lower than a bottom surface of the first trench T 1 . The second trench T 2 may be filled with the second field insulating film 130 . Accordingly, the first trench T 1 may be filled with the first field insulating film 120 and the second field insulating film 130 . At this time, the first field insulating film 120 may contact an inner side surface of the first trench T 1 in the second direction Y 1 , but may not contact the second field insulating film 130 . The first field insulating film 120 may contact both sides of the second field insulating film 130 . [0050] The first field insulating film 120 may be formed on the substrate 100 , and disposed around the first to the fourth fin-type patterns F 1 -F 4 . The first field insulating film 120 is formed so as to partially surround the first to the fourth fin-type patterns F 1 -F 4 , and a portion of the first to the fourth fin-type patterns F 1 -F 4 may protrude upward higher than an upper surface of the first field insulating film 120 . For example, the first field insulating film 120 may partially fill the first to the fourth shallow trenches ST 1 -ST 4 . [0051] For example, the first field insulating film 120 may be an oxide layer, a nitride layer, an oxynitride layer or a multi-layer combining thereof. Further, the first field insulating film 120 may include poly silazene (PSZ), undoped silica glass (USG) or high-density plasma deposition (HDP) oxide. The present inventive concept is not limited thereto. [0052] The second field insulating film 130 may be formed on the substrate 100 and disposed in the deep trench DT. A portion of the first to the fourth fin-type patterns F 1 -F 4 may protrude upward higher than the upper surface of the second field insulating film 130 . For example, the upper surface of the second field insulating film 130 may be formed lower than the upper surfaces of the first to the fourth fin-type patterns F 1 -F 4 . [0053] The second field insulating film 130 may include a first region 130 - 1 and a second region 130 - 2 . The first region 130 - 1 may be in contact with the first field insulating film 120 . The first region 130 - 1 may be located between the first field insulating film 120 and the second region 130 - 2 . The first region 130 - 1 , together with the second region 130 - 2 , may fill the deep trench DT. [0054] The second region 130 - 2 may be formed at a farther distance from the second fin-type pattern F 2 (or 110 ) and the third fin-type pattern F 3 , than the first region 130 - 1 is. The second region 130 - 2 may be in an integrated structure with the first region 130 - 1 . The second region 130 - 2 , together with the first region 130 - 1 , may fill the deep trench DT. [0055] For example, the second field insulating film 130 may be an oxide layer, a nitride layer, an oxynitride layer or a multi-layer combining thereof. In an exemplary embodiment, the second field insulating film 130 may include, for example, silicon oxide, silicon nitride, silicon oxynitride, or a low-k dielectric material with a smaller dielectric constant than silicon oxide. For example, the low-k dielectric material may include flowable oxide (FOX), Tonen silazene (TOSZ), borosilica glass (BSG), phosphosilica glass (PSG), borophosphosilica glass (BPSG), plasma enhanced tetra ethyl ortho silicate (PETEOS), fluoride silicate glass (FSG), carbon doped silicon oxide (CDO), xerogel, aerogel, amorphous fluorinated carbon, organo silicate glass (OSG), parylene, bis-benzocyclobutenes (BCB), SILK, polyimide, porous polymeric material, or a combination thereof, but the present inventive concept is not limited thereto. [0056] An upper surface of the first region 130 - 1 of the second field insulating film 130 may be lower than an upper surface of the second region 130 - 2 . The upper surface of the first region 130 - 1 of the second field insulating film 130 may be higher than the upper surface of the first field insulating film 120 . For example, the upper surface of the second region 130 - 2 of the second field insulating film 130 may be higher than the upper surface of the first field insulating film 120 . The heights of the upper surfaces of the first region 130 - 1 and the second region 130 - 2 of the second field insulating film 130 may be lower than the heights of the first to the fourth fin-type patterns F 1 -F 4 . [0057] A lower surface of the first portion 120 a of the first field insulating film may be in contact with the bottom surface of the first shallow trench ST 2 , and the lower surface of the second field insulating film 130 may be in contact with the bottom surface of the deep trench DT. Accordingly, the lower surface of the first field insulating film 120 may be higher than the lower surface of the second field insulating film 130 . [0058] The first gate electrode 210 may be formed to extend in the second direction Y 1 and intersect the first to the fourth fin-type patterns F 1 -F 4 . The first gate electrode 210 may be disposed on the first to the fourth fin-type patterns F 1 -F 4 , and on the first field insulating film 120 and the second field insulating film 130 . The first gate electrode 210 may be formed on the first portion 110 - 1 of the second fin-type pattern. [0059] The first gate electrode 210 may be formed on the first to the fourth fin-type patterns F 1 -F 4 , and on the first field insulating film 120 and the second field insulating film 130 . The first gate electrode 210 may be formed to partially surround the side surfaces of the first to the fourth fin-type patterns F 1 -F 4 and surround the upper surfaces of the first to the fourth fin-type patterns F 1 -F 4 . The bottom surface of the first gate electrode 210 may be formed along the profile of the first to the fourth fin-type patterns F 1 -F 4 , the first field insulating film 120 and the second field insulating film 130 , i.e., formed along the profile of the upper surfaces of the first and the second field insulating films 120 and 130 . [0060] The first gate electrode 210 may have a first thickness h 1 at a portion overlapping the second region 130 - 2 of the second field insulating film 130 . The first gate electrode 210 may have a second thickness h 2 at a portion overlapping the first region 130 - 1 of the second field insulating film 130 . The first gate electrode 210 may have a third thickness h 3 at a portion overlapping the first field insulating film 120 . The first gate electrode 210 may have a fourth thickness h 4 at a portion overlapping the second fin-type pattern F 2 (or 110 ). [0061] As illustrated, the first thickness h 1 is smaller than the second thickness h 2 , and the second thickness h 2 is smaller than the third thickness h 3 . Further, the fourth thickness h 4 is smaller than the first thickness h 1 . [0062] The upper surface of the first gate electrode 210 may be formed to be coplanar by a chemical-mechanical planarization (CMP) process. Accordingly, the thickness of the first gate electrode 210 may have different thickness along the second direction Y 1 according to the profile of the lower surface of the first gate electrode 210 . [0063] The fourth thickness h 4 of the first gate electrode 210 may be smaller than the first thickness h 1 , the second thickness h 2 and the third thickness h 3 , because the height of the upper surface of the second fin-type pattern 110 is greater than the heights of the upper surfaces of the first field insulating film 120 and the second field insulating film 130 . [0064] The first thickness h 1 of the first gate electrode 210 may be smaller than the second thickness h 2 and the third thickness h 3 , because the upper surface of the second region 130 - 2 of the second field insulating film 130 is higher than the upper surface of the first region 130 - 1 of the second field insulating film 130 and higher than the upper surface of the first field insulating film 120 . [0065] Gate insulating films 211 and 212 may be formed between the first to the fourth fin-type patterns F 1 -F 4 and the first gate electrode 210 . The gate insulating films 211 and 212 may include an interfacial layer 211 and a high-k dielectric insulating film 212 . [0066] The interfacial layer 211 may be formed by partially oxidizing the first fin-type pattern 110 . The interfacial layer 211 may be formed along the profile of the first fin-type pattern 110 protruding upward higher than the upper surfaces of the first and the second field insulating films 120 and 130 . In an exemplary embodiment, the first fin-type pattern 110 is a silicon fin-type pattern including silicon, and the interfacial layer 211 may include a silicon oxide layer. [0067] In an exemplary embodiment, the interfacial layer 211 may be formed along the upper surfaces of the first and the second field insulating films 120 and 130 . In an exemplary embodiment, the interfacial layer 211 may be formed along the upper surfaces of the first and the second field insulating films 120 and 130 according to a method of forming the interfacial layer 211 . For example, the interfacial layer 211 may be conformally formed by a deposition process such as a chemical vapor deposition (CVD) process. [0068] Further, even in an example where the first and the second field insulating films 120 , 130 include silicon oxide, the interfacial layer 211 may be formed along the upper surfaces of the first and the second field insulating films 105 , 106 , if there is difference in the physical properties between the silicon oxide included in the first and the second field insulating films 120 , 130 and the silicon oxide layer included in the interfacial layer 211 . [0069] The high-k dielectric insulating film 212 may be formed between the interfacial layer 211 and the first gate electrode 210 . The high-k dielectric insulating film 212 may be formed along the profile of the first fin-type pattern 110 protruding upward higher than the upper surfaces of the first and the second field insulating films 120 and 130 . Further, the high-k dielectric insulating film 212 may be formed between the first gate electrode 210 , and the first field insulating film 120 and the second field insulating film 130 . [0070] For example, the high-k dielectric insulating film 212 may include silicon oxynitride, silicon nitride, hafnium oxide, hafnium silicon oxide, lanthanum oxide, lanthanum aluminum oxide, zirconium oxide, zirconium silicon oxide, tantalum oxide, titanium oxide, barium strontium titanium oxide, barium titanium oxide, strontium titanium oxide, yttrium oxide, aluminum oxide, lead scandium tantalum oxide, or lead zinc niobate, and the present inventive concept is not limited thereto. [0071] A gate spacer 215 may be disposed on a sidewall of the first gate electrode 210 extending in the second direction Y 1 . The gate spacer 215 may include, for example, silicon nitride (SiN), silicon oxynitride (SiON), silicon oxide (SiO 2 ), silicon oxycarbonitride (SiOCN), or a combination thereof. [0072] The source/drain 115 may be formed on both sides of the first gate electrode 210 , and on the first fin-type pattern 110 . [0073] For example, the source/drain 115 may be formed on the second portion 110 - 2 of the first fin-type pattern. [0074] The source/drain 115 may be formed of an epitaxial layer formed by epitaxy. In an exemplary embodiment, the source/drain 115 may be an elevated source/drain. The epitaxial layer 115 e may fill a recess 110 r formed in the second portion 110 - 2 of the first fin-type pattern. [0075] An outer circumference of the epitaxial layer 115 e may have a variety of shapes. For example, the shape of the outer circumference of the epitaxial layer 115 e may have diamond, circle or rectangle. FIG. 4 illustrates a diamond shape (or pentagon or hexagon shape), for an example. [0076] In an exemplary embodiment, the semiconductor device 1 may be a P-type Metal-Oxide-Semiconductor (PMOS) transistor, and the source/drain may include a compressive stress material. For example, the compressive stress material may be SiGe which has a higher lattice constant compared to Si. For example, the compressive stress material may increase mobility of the carrier in the channel region by exerting compressive stress on the first fin-type pattern 110 . [0077] In an exemplary embodiment, the semiconductor device 1 may be an N-type Metal-Oxide-Semiconductor (NMOS) transistor, and the source/drain 115 may include a tensile stress material. For example, the first fin-type pattern 110 is silicon, and the tensile stress material may include SiC which has a smaller lattice constant than the silicon. For example, the tensile stress material may increase mobility of the carrier in the channel region by exerting tensile stress on the first fin-type pattern 110 . [0078] An interlayer insulating film 190 may cover the first fin-type pattern 110 , the source/drain 115 and the first gate electrode 210 . The interlayer insulating film 190 may be formed on the first and the second field insulating films 120 and 130 . [0079] For example, the interlayer insulating film 190 may include silicon oxide, silicon nitride, silicon oxynitride, or a low-k dielectric material with a smaller dielectric constant than silicon oxide. For example, the low-k dielectric material may include flowable oxide (FOX), Tonen silazene (TOSZ), undoped silica glass (USG), borosilica glass (BSG), phosphosilica glass (PSG), borophosphosilica glass (BPSG), plasma enhanced tetra ethyl ortho silicate (PETEOS), fluoride silicate glass (FSG), carbon doped silicon oxide (CDO), xerogel, aerogel, amorphous fluorinated carbon, organo silicate glass (OSG), parylene, bis-benzocyclobutenes (BCB), SILK, polyimide, porous polymeric material, or a combination thereof, but the present inventive concept is not limited thereto. [0080] The material of the first field insulating film 120 may have a higher etch rate than the material of the second field insulating film 130 . In this case, a simultaneous etching process performed on the first field insulating film 120 and the second field insulating film 130 may form different heights of the first field insulating film 120 and the second field insulating film 130 . For example, the second field insulating film 130 may be formed with a higher upper surface than that of the first field insulating film 120 . [0081] As the heights of the upper surfaces of the first field insulating film 120 and the second field insulating film 130 increase, the lower surface of the first gate electrode 210 may have a relatively increased height. That is, as the thickness or the volume of the first gate electrode 210 decreases, the effective capacitance thereof will decrease, thus further enhancing AC performance and reliability of the semiconductor device 1 . That is, the first gate electrode 210 and the source/drain 115 can have enhanced AC performances. [0082] Hereinbelow, a semiconductor device 2 according to an exemplary embodiment will be explained with reference to FIGS. 1 and 5 . The description of those described above with respect to the semiconductor device 1 will omitted or be made as brief as possible. [0083] FIG. 5 is a cross sectional view of a semiconductor device according to an exemplary embodiment. FIG. 5 is a cross sectional view taken along line B-B′ of FIG. 1 . [0084] Referring to FIG. 5 , the semiconductor device 2 may include a liner 112 . [0085] The liner 112 may be formed within the first to the fourth shallow trenches ST 1 -ST 4 . The liner 112 may be formed conformally along the bottom surfaces and the side surfaces of the first to the fourth shallow trenches ST 1 -ST 4 . In an exemplary embodiment, the liner 112 may be formed only partially on the side surfaces of the first to the fourth shallow trenches ST 1 -ST 4 . The first field insulating film 120 may partially fill the first to the fourth shallow trenches ST 1 -ST 4 , and the liner 112 may be formed between the first field insulating film 120 and the substrate 100 . The liner 112 need not be formed on the side surfaces of the first to the fourth fin-type patterns F 1 -F 4 which protrude farther than the first field insulating film 120 . [0086] Hereinbelow, a semiconductor device 3 according to an exemplary embodiment will be explained with reference to FIGS. 1, 6 and 7 . The descriptions of those described above with reference to the semiconductor devices 1 and 2 will be omitted or will be made as brief as possible. [0087] FIGS. 6 and 7 are cross sectional views of a semiconductor device according to an exemplary embodiment. FIG. 6 is a cross sectional view taken along line B-B′ of FIG. 1 , and FIG. 7 is an expanded view of the encircled area D of FIG. 6 . [0088] Referring to FIGS. 6 and 7 , the semiconductor device 3 may include a second field insulating film 130 and a third field insulating film 140 . [0089] The third field insulating film 140 may partially fill the deep trench DT. The third field insulating film 140 may be in contact with the bottom surface and the side surface of the deep trench DT. The third field insulating film 140 may be formed conformally on the bottom surface and the side surface of the deep trench DT. [0090] The third field insulating film 140 may include a recess R. The recess R may be formed on the third field insulating film 140 . A side surface of the recess R may be the third field insulating film 140 , and a bottom surface of the recess R may also be the third field insulating film. [0091] The second field insulating film 130 may fill the recess R. The second field insulating film 130 and the first field insulating film 120 may be spaced apart from each other. The third field insulating film 140 may be formed between the second field insulating film 130 and the first field insulating film 120 . [0092] The uppermost portion of the upper surface of the third field insulating film 140 may be higher than the upper surface of the first field insulating film 120 and lower than the upper surface of the second field insulating film 130 . The etch rate of the material of the third field insulating film 140 may be higher than the etch rate of the second field insulating film 130 . The etch rate of the material of the third field insulating film 140 may be equal to or lower than the etching rate of the first field insulating film 120 . [0093] The third field insulating film 140 may include the same material as the first field insulating film 120 . For example, the third field insulating film 140 may include poly silazene (PSZ), undoped silica glass (USG) or high-density plasma deposition (HDP) oxide, and the present inventive concept is not limited thereto. [0094] The first gate electrode 210 may have a fifth thickness h 5 at a portion overlapping the third field insulating film 140 . The fifth thickness h 5 may be thicker than the first thickness h 1 , the second thickness h 2 and the fourth thickness h 4 . The fifth thickness h 5 may be thinner than the third thickness h 3 . This is attributable to the relationship between the height of the upper surface of the third field insulating film 140 , and the heights of the upper surfaces of the second fin-type pattern F 2 (or 110 ), the first field insulating film 120 and the second field insulating film 130 . [0095] As illustrated in FIG. 6 , the bottom surface of the recess R may be formed higher than the bottom surfaces of the first shallow trench ST 1 and the second shallow trench ST 2 . The present inventive concept is not limited thereto. The depth of the recess R may be set such that the second field insulating film 130 may fill the recess R completely without forming an air gap between the second field insulating film 130 and the third field insulating film 140 . For example, the depth of the recess R may vary according to the gap filling capability of the second field insulating film 130 . [0096] The second field insulating film 130 may have less gap filling capability compared to the first field insulating film 120 . If the deep trench DT is formed with the second field insulating film 130 only, an air gap may be formed in the deep trench DT, and thus the performance and reliability of the semiconductor device 3 may be reduced. Accordingly, the third field insulating film 140 may be first formed in the deep trench DT, and then the second field insulating film 130 may fill up the remaining space of the deep trench DT. [0097] In this manner, the third field insulating film 140 may completely fill up the inner space of the deep trench DT, and the second field insulating film 130 may have an upper surface formed high such that the thickness of the first gate electrode 210 is reduced. The capacitance between the gate electrode and the source/drain may be reduced and the interior of the deep trench DT may be filled without generating an air gap. [0098] The uppermost portion of the upper surface of the third field insulating film 140 , i.e., the upper surface of the third field insulating film 140 which is exposed, i.e., not covered by the second field insulating film 130 may have a predetermined width ‘a’ in the second direction Y 1 . If the third field insulating film 140 has a width greater than the width ‘a’, the area of the second field insulating film 130 may decrease, and thus the capacitance reduction effect of the increased height of the upper surface of the second field insulating film 130 may decrease. If the third field insulating film 140 has a width smaller than the width ‘a’, an air gap may be formed between the second field insulating film 130 and the third field insulating film 140 . For example, the first gate electrode 210 or the gate insulating films 211 and 212 need not be formed conformally. Accordingly, the predetermined width ‘a’ may be set so that the recess R may be completely filled without reducing the capacitance reduction effect. For example, the width ‘a’ may be less than about 30 nm. [0099] Hereinbelow, a semiconductor device 4 according to an exemplary embodiment will be explained with reference to FIGS. 1 and 8 . The descriptions of those described above with reference to the semiconductor devices 1 - 3 will be omitted or will be made as brief as possible. [0100] FIG. 8 is a cross sectional view of a semiconductor device 4 according to an exemplary embodiment. FIG. 8 is a cross sectional view taken along line B-B′ of FIG. 1 . [0101] Referring to FIG. 8 , the semiconductor device 4 may include a third field insulating film 140 disposed in a recess R, an upper sidewall of the third field insulating film 140 is in contact with the first field insulating film and a lower sidewall of the third field insulating film 140 is spaced apart from the first field insulating film 120 . [0102] Accordingly, a portion of the side surface of the second field insulating film 130 formed in the recess R may be in contact with the first field insulating film 120 , and the rest portion of the side surface of the second field insulating film 130 may be in contact with the third field insulating film 140 . The upper surface of the third field insulating film 140 may be fully covered by the second field insulating film 130 and need not be exposed. [0103] In this case, the second field insulating film 130 may be formed to fill the deep trench D between the first portion 120 a and the second portion 120 b of the first field insulating film. At this time, since the upper surface of the second field insulating film 130 is formed higher than the upper surface of first field insulating film 120 , the capacitance of the first gate electrode 210 may be reduced and the AC performance of the semiconductor device 4 may be enhanced. [0104] Further, since the upper surface of the third field insulating film 140 is fully covered by the second field insulating film 130 , generation of an air gap may be prevented in the subsequent process between the third field insulating film 140 and the first gate electrode 210 . Accordingly, the semiconductor device 4 can have increased performance. [0105] Hereinbelow, a semiconductor device 5 according to an exemplary embodiment will be explained with reference to FIGS. 1 and 9 . The descriptions of those described above with reference to the semiconductor devices 1 - 4 will be omitted or will be made as brief as possible. [0106] FIG. 9 is a cross sectional view of the semiconductor device 5 according to an exemplary embodiment. FIG. 9 is a cross sectional view taken along line B-B′ of FIG. 1 . [0107] Referring to FIG. 9 , the semiconductor device 5 may include a recess R of which sidewall is in contact with a first field insulating film 120 . [0108] The side surface of a second field insulating film 130 formed in the recess R may be in contact with the first field insulating film 120 . The upper surface of a third field insulating film 140 may be fully covered by the second field insulating film 130 and need not be exposed. [0109] The sidewall of a deep trench DT may include a first region I and a second region II. The first region I may be in contact with the second field insulating film 130 , and the second region II may be in contact with the third field insulating film 140 . The first region I may be located on the second region II. [0110] The second field insulating film 130 may fill the first region I of the deep trench DT disposed between the first portion 120 a and the second portion 120 b of the first field insulating film. The upper surface of the second field insulating film 130 is formed high, and the capacitance of the first gate electrode 210 may be reduced and the AC performance of the semiconductor device 5 may be increased. [0111] Further, since the upper surface of the third field insulating film 140 is fully covered by the second field insulating film 130 , generation of an air gap may be prevented in the subsequent process. Accordingly, the semiconductor device 5 may have increased performance. [0112] Hereinbelow, a semiconductor device 6 according to an exemplary embodiment will be explained with reference to FIGS. 1 and 10 . The descriptions of those described above with reference to FIGS. 1 and 10 will be omitted or will be made as brief as possible. [0113] FIG. 10 is a cross sectional view of the semiconductor device 6 according to an exemplary embodiment. FIG. 10 is a cross sectional view taken along line B-B′ of FIG. 1 . [0114] Referring to FIG. 10 , the semiconductor device 6 may include a curved upper surface formed by an upper surface of a second field insulating film 130 and an upper surface of a third field insulating film 140 . [0115] The upper surface of the first field insulating film 120 may be lower than the upper surface of the third field insulating film 140 . The upper surface of the first field insulating film 120 may be in a bowl shape. For example, the upper surface of the first field insulating film 120 may include a portion that is lower than a contacting portion between the upper surface of the first field insulating film 120 and the second fin-type pattern F 2 (or 110 ). [0116] The uppermost portion of the upper surface of the third field insulating film 140 may be higher than the upper surface of the first field insulating film 120 and lower than the upper surface of the second field insulating film 130 . The uppermost portion of the third field insulating film 140 may be located on the exposed upper surface of the third field insulating film 140 . For example, the upper surface that is not covered by the second field insulating film 130 may include the uppermost portion of the upper surface of the third field insulating film 140 . The exposed, upper surface of the third field insulating film 140 may be higher than the upper surface of the first field insulating film 120 and lower than the upper surface of the second field insulating film 130 . [0117] The second field insulating film 130 may be in a convex shape. The uppermost portion of the upper surface of the second field insulating film 130 may be formed higher than the height of a portion at which the second field insulating film 130 and the third field insulating film 140 meet. As illustrated, there may be two portions at which the second field insulating film 130 and the third field insulating film 140 meet in the second direction Y 1 , and the uppermost portion of the second field insulating film 130 may be located between these two portions. [0118] FIG. 11 is a block diagram of an SoC system 1000 comprising a semiconductor device according to an exemplary embodiment. [0119] Referring to FIG. 11 , the SoC system 1000 includes an application processor 1001 and a dynamic random-access memory (DRAM) 1060 . [0120] The application processor 1001 may include a central processing unit (CPU) 1010 , a multimedia system 1020 , a bus 1030 , a memory system 1040 and a peripheral circuit 1050 . [0121] The CPU 1010 may perform an arithmetic operation necessary for the driving of the SoC system 1000 . In an exemplary embodiment, the CPU 1010 may be configured on a multi-core environment which includes a plurality of cores. [0122] The multimedia system 1020 may be used for performing a variety of multimedia functions on the SoC system 1000 . The multimedia system 1020 may include a three-dimensional (3D) engine module, a video codec, a display system, a camera system, or a post-processor. [0123] The bus 1030 may be used for exchanging data communication among the CPU 1010 , the multimedia system 1020 , the memory system 1040 and the peripheral circuit 1050 . In some exemplary embodiments, the bus 1030 may have a multi-layer structure. Specifically, an example of the bus 1030 may be a multi-layer advanced high-performance bus (AHB), or a multi-layer advanced eXtensible interface (AXI), and the present inventive concept is not limited herein. [0124] The memory system 1040 may provide environments necessary for the application processor 1001 to connect to an external memory (e.g., DRAM 1060 ) and perform high-speed operation. In some exemplary embodiments, the memory system 1040 may also include a separate controller (e.g., DRAM controller) to control an external memory (e.g., DRAM 1060 ). [0125] The peripheral circuit 1050 may provide environments necessary for the SoC system 1000 to have a seamless connection to an external device (e.g., main board). Accordingly, the peripheral circuit 1050 may include a variety of interfaces to allow compatible operation with the external device connected to the SoC system 1000 . [0126] The DRAM 1060 may function as an operation memory necessary for the operation of the application processor 1001 . In some exemplary embodiments, the DRAM 1060 may be arranged externally to the application processor 1001 , as illustrated. Specifically, the DRAM 1060 may be packaged into a package on package (PoP) type with the application processor 1001 . [0127] At least one of the above-mentioned components of the SoC system 1000 may include a semiconductor device according to an exemplary embodiment of the present inventive concept. [0128] FIG. 12 is a block diagram of an electronic system comprising a semiconductor device according to an exemplary embodiment. [0129] Referring to FIG. 12 , the electronic system 1100 may include a controller 1110 , an input/output (I/O) device 1120 , a memory device 1130 , an interface 1140 and a bus 1150 . The controller 1110 , the I/O device 1120 , the memory device 1130 and/or the interface 1140 may be coupled with one another via the bus 1150 . The bus 1150 corresponds to a path through which data travels. [0130] The controller 1110 may include at least one of microprocessor, digital signal process, micro controller and logic devices capable of performing functions similar to those mentioned above. The I/O device 1120 may include a keypad, a keyboard or a display device. The memory device 1130 may store data and/or commands. The interface 1140 may perform a function of transmitting or receiving data to or from communication networks. The interface 1140 may be wired or wireless. For example, the interface 1140 may include an antenna or a wired/wireless transceiver. [0131] Although not illustrated, the electronic system 1100 may additionally include an operation memory configured to enhance operation of the controller 1110 , such as a high-speed dynamic random-access memory (DRAM) and/or a static random access memory (SRAM). [0132] A semiconductor device fabricated according to an exemplary embodiment of the present inventive concept may be provided within the memory device 1130 , or the controller 1110 or the I/O device 1120 . [0133] The electronic system 1100 is applicable to a personal digital assistant (PDA) portable computer, a web tablet, a wireless phone, a mobile phone, a digital music player, a memory card, or almost all electronic products that are capable of transmitting and/or receiving data in wireless environment. [0134] FIGS. 13 to 15 illustrate exemplary semiconductor systems including a semiconductor device according to an exemplary embodiment. [0135] FIG. 13 illustrates a tablet PC 1200 , FIG. 14 illustrates a laptop computer 1300 , and FIG. 15 illustrates a smartphone 1400 . According to the exemplary embodiments explained above, the semiconductor device may be used in these devices, i.e., in the tablet PC 1200 , the laptop computer 1300 or the smartphone 1400 . [0136] A semiconductor device according to an exemplary embodiment may be applicable to an integrated circuit device not illustrated herein. [0137] For example, an exemplary semiconductor system need not be limited to the tablet PC 1200 , the laptop computer 1300 and the smartphone 1400 which are exemplified above. [0138] In an exemplary embodiment, the semiconductor system may include a computer, a ultra mobile PC (UMPC), a workstation, a net-book, personal digital assistants (PDA), a portable computer, a wireless phone, a mobile phone, an e-book, a portable multimedia player (PMP), a portable game player, a navigation device, a black box, a digital camera, a three-dimensional television, a digital audio recorder, a digital audio player, a digital picture recorder, a digital picture player, a digital video recorder, or a digital video player. [0139] Hereinbelow, a method of fabricating a semiconductor device according to an exemplary embodiment will be explained with reference to FIGS. 3 and 16 to 19 . FIGS. 16 to 19 are cross sectional views showing a method of fabricating a semiconductor device according to an exemplary embodiment. In the following description, descriptions of those described above with reference to the semiconductor devices 1 - 6 will be omitted or will be made as brief as possible for the sake of brevity. [0140] Referring to FIG. 16 , a fin-type pattern F and a shallow trench ST are formed on a substrate 100 . A plurality of fin-type patterns F and a plurality of shallow trenches ST may be formed. The fin-type pattern F may be defined by the shallow trench ST, and the shallow trench ST may be defined by the fin-type pattern F. For example, a side surface of the fin-type pattern F may be a sidewall of the shallow trench ST. The height of the fin-type pattern F may be substantially the same with the depth of the shallow trench ST. The fin-type patterns F may be spaced apart from each other at a uniform interval. The shallow trenches ST may also be spaced apart from each other at a uniform interval. [0141] A first field insulating film 120 may fill the shallow trench ST. The first field insulating film 120 may completely fill the shallow trench ST. An upper surface of the fin-type pattern F and an upper surface of the first field insulating film 120 may be formed to be coplanar with each other. The term “coplanar surfaces” refers to surfaces being made planar by the planarization process and may include a presence of minute stepped portions. [0142] Next, a mask layer M is formed on the first field insulating film 120 and the fin-type pattern F. The mask layer M may be uniformly formed on the first field insulating film 120 and the fin-type pattern F. [0143] Referring to FIG. 17 , a deep trench DT is formed by etching the mask layer M, the fin-type pattern F and the first field insulating film 120 . [0144] The deep trench DT may be formed deeper than the shallow trench ST. The fin-type pattern F may be partially removed by the deep trench DT. A portion of the first field insulating film 120 may be completely removed by the deep trench DT, while the rest portion of the first field insulating film 120 may be partially removed. However, the present inventive concept is not limited thereto. [0145] The deep trench DT may include an inclined sidewall as illustrated, having a downwardly decreasing width. However, the present inventive concept is not limited thereto. [0146] Referring to FIG. 18 , a second preliminary field insulating film 130 P 1 is formed. The second preliminary field insulating film 130 P 1 may fill the deep trench DT. The second preliminary field insulating film 130 P 1 may be formed on the mask layer M. The second preliminary field insulating film 130 P 1 may be etched later to become the second field insulating film 130 . [0147] Referring to FIG. 19 , a portion of the second preliminary field insulating film 130 P 1 and the mask layer M are removed. With the partial removal, the second preliminary field insulating film 130 P 1 may be planarized to be a second planarized field insulating film 130 P 2 . [0148] An upper surface of the second planarized field insulating film 130 P 2 may be substantially coplanar with the upper surface of the first field insulating film 120 and a upper surface of the fin-type pattern F. The second planarized field insulating film 130 P 2 may be etched so that the second field insulating film 130 may be formed, as shown in FIG. 3 , for example. [0149] Referring back to FIG. 3 , the second planarized field insulating film 130 P 2 and the first field insulating film 120 may be etched to thus form the second field insulating film 130 . These etching processes may be performed at the same time. For example, the first field insulating film 120 and the second planarized field insulating film 130 P 2 may be etched simultaneously. The second planarized field insulating film 130 P 2 has a lower etch rate compared to the first field insulating film 120 . Accordingly, the upper surface of the second field insulating film 130 may be higher than the upper surface of the first field insulating film 120 . [0150] The gate insulating films 211 and 212 may then be formed on the first field insulating film 120 and the second field insulating film 130 . The first gate electrode 210 may then be formed on the gate insulating films 211 , 212 . The thickness of the first gate electrode 210 may vary according to a profile of the upper surfaces of the first field insulating film 120 and the second field insulating film 130 . Accordingly, the thickness of the first gate electrode 210 may be decreased due to the upper surface of the second field insulating film 130 which is formed higher than the upper surface of the first field insulating film 120 . As a result, the parasitic capacitance between the first gate electrode 210 and the source/drain 115 , as shown in FIG. 2 for example, may be reduced. [0151] Hereinbelow, a method of fabricating a semiconductor device according to an exemplary embodiment will be explained with reference to FIGS. 1, 2, 6, 16, 17, 20 and 21 . FIGS. 20 and 21 show a method of fabricating a semiconductor device according to an exemplary embodiment. In the following description, descriptions of those described above with reference to the semiconductor devices 1 - 6 will be omitted or will be made as brief as possible for the sake of brevity. [0152] Referring to FIG. 20 , a third preliminary field insulating film 140 P 1 and a second preliminary field insulating film 130 P 1 are formed. [0153] The third preliminary field insulating film 140 P 1 may partially fill the deep trench DT. The third preliminary field insulating film 140 P 1 may be conformally formed along the side surface and the bottom surface of the deep trench DT. The third preliminary field insulating film 140 P 1 may have a recess formed on the upper surface. The second preliminary field insulating film 130 P 1 may be formed in the recess. The third preliminary field insulating film 140 P 1 may be formed on the mask layer M. The third preliminary field insulating film 140 P 1 may be etched later to become the third field insulating film 140 . [0154] The second preliminary field insulating film 130 P 1 may completely fill the deep trench DT. For example, the second preliminary field insulating film 130 P 1 may fill the recess. The second preliminary field insulating film 130 P 1 may be formed on the third preliminary field insulating film 140 P 1 . The second preliminary field insulating film 130 P 1 may be etched later to become the second field insulating film 130 . [0155] In an exemplary embodiment, the second preliminary field insulating film 130 P 1 and the third preliminary field insulating film 140 P 1 are formed of silicon nitride and silicon oxide, respectively. [0156] Referring to FIG. 21 , a portion of the second preliminary field insulating film 130 P 1 , a portion of the third preliminary field insulating film 140 P 1 , and the mask layer M are removed. With the partial removal, the third preliminary field insulating film 140 P 1 may become a third planarized field insulating film 140 P 2 . With the partial removal, the second pre-field insulating film 130 P 1 may become a second planarized field insulating film 130 P 2 . [0157] An upper surface of the third planarized field insulating film 140 P 2 , and an upper surface of the second planarized field insulating film 130 P 2 may be substantially coplanar with the upper surface of the first field insulating film 120 and the upper surface of the fin-type pattern F. The term “coplanar” may include a presence of minute stepped portions. The second planarized field insulating film 130 P 2 may be etched later to become the second field insulating film 130 , and the third planarized field insulating film 140 P 2 may be etched later to become the third field insulating film 140 . [0158] Referring back to FIG. 6 , the third planarized field insulating film 140 P 2 , the second planarized field insulating film 130 P 2 , and the first field insulating film 120 may be etched to thus form the third field insulating film 140 and the second field insulating film 130 . These etching processes may be performed at the same time. For example, the third planarized field insulating film 140 P 2 , the first field insulating film 120 and the second planarized field insulating film 130 P 2 may be etched simultaneously. The third field insulating film 140 may have a lower etch rate compared to the first field insulating film 120 . Accordingly, the upper surface of the third field insulating film may be higher than the upper surface of the first field insulating film 120 . Further, the second field insulating film 130 may have a lower etch rate compared to the third field insulating film 140 . Accordingly, the upper surface of the second field insulating film 130 may be higher than the upper surface of the third field insulating film 140 . [0159] The gate insulating films 211 and 212 may then be formed on the third field insulating film 140 , the first field insulating film 120 and the second field insulating film 130 . The first gate electrode 210 may then be formed on the gate insulating films 211 and 212 . The thickness of the first gate electrode 210 may vary along the second direction of Y 1 according to a profile of the upper surfaces of the third field insulating film 140 , the first field insulating film 120 and the second field insulating film 130 . Accordingly, the thickness of the first gate electrode 210 may be decreased due to the upper surface of the third field insulating film 140 and the upper surface of the second field insulating film 130 which are formed higher than the upper surface of the first field insulating film 120 . As a result, the parasitic capacitance between the first gate electrode 210 and the source/drain 115 may be reduced. [0160] Hereinbelow, a method of fabricating a semiconductor device according to an exemplary embodiment will be explained with reference to FIGS. 1, 2, 6, 16, 17, 21 and 22 . FIG. 22 shows a method of fabricating a semiconductor device according to an exemplary embodiment. In the following description, the descriptions of those made with reference to the semiconductor devices 1 - 6 and the method for fabricating a semiconductor device described above will be omitted or will be made as brief as possible for the sake of brevity. [0161] Accordingly, the redundant description of the processes illustrated and described with reference to FIGS. 16 and 17 will be omitted. [0162] Referring to FIG. 22 , the third preliminary field insulating film 140 P 1 , the second preliminary field insulating film 130 P 1 and a third dummy field insulating film 142 are formed. [0163] The third preliminary field insulating film 140 P 1 may partially fill the deep trench DT. The third preliminary field insulating film 140 P 1 may be conformally formed along the side surface and the bottom surface of the deep trench DT. The third preliminary field insulating film 140 P 1 may have a recess formed on the upper surface. The second preliminary field insulating film 130 P 1 may be formed in the recess R. The third preliminary field insulating film 140 P 1 may be only partially formed on the side surface of the deep trench DT. The third preliminary field insulating film 140 P 1 may be etched later to become the third field insulating film 140 . [0164] The second preliminary field insulating film 130 P 1 may partially fill the deep trench DT. For example, the second preliminary field insulating film 130 P 1 may fill the recess. The second preliminary field insulating film 130 P 1 may be formed on the third preliminary field insulating film 140 P 1 . The second preliminary field insulating film 130 P 1 may be etched later to become the second field insulating film 130 . The upper surface of the second preliminary field insulating film 130 P 1 may be formed higher than the upper surface of the third preliminary field insulating film 140 P 1 . However, the present inventive concept is not limited thereto. [0165] The upper surface of the second preliminary field insulating film 130 P 1 may be formed higher than the fin-type pattern F. A height difference G between the upper surface of the second preliminary field insulating film 130 P 1 and the upper surface of the fin-type pattern F may have about 50 nm or less, for example, because the upper surface of the second field insulating film 130 has to be lower than the upper surface of the fin-type pattern F after the simultaneous etching of the second preliminary field insulating film 130 P 1 and the third preliminary field insulating film 140 P 1 . [0166] However, the present inventive concept is not limited thereto. For example, the upper surface of the second pre-field insulating film 130 P 1 may be formed lower than or equal to the fin-type pattern F. [0167] The third dummy field insulating film 142 may be formed on the second preliminary field insulating film 130 P 1 and the third pre-field insulating film 140 P 1 . The third dummy field insulating film 142 may completely fill the deep trench DT. The third dummy field insulating film 142 may also be formed conformally on the mask layer M. The third dummy field insulating film 142 and the third preliminary field insulating film 140 P 1 may be formed of substantially the same material. Accordingly, while the interface between the third dummy field insulating film 142 and the third preliminary field insulating film 140 P 1 is illustrated herein, in an exemplary embodiment, the interface need exist. [0168] The forming of the third dummy field insulating film 142 may facilitate forming of the coplanar upper surfaces of the third field insulating film 140 , the first field insulating film 120 and the second field insulating film 130 during the subsequent planarization process. [0169] The subsequent processes according to FIGS. 21 and 6 are then performed in the same manner as described above. [0170] While the present inventive concept has been shown and described with reference to exemplary embodiments thereof, it will be apparent to those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the inventive concept as defined by the following claims.

A semiconductor device is provided as follows. A first fin-type pattern is disposed on a substrate. A first field insulating film is adjacent to a sidewall of the first fin-type pattern. A second field insulating film is adjacent to a sidewall of the first field insulating film. The first field insulating film is interposed between the first fin-type pattern and the second field insulating film. The second field insulating film comprises a first region and a second region. The first region is closer to the sidewall of the first field insulating film. A height from a bottom of the second field insulating film to an upper surface of the second region is larger than a height from the bottom of the second field insulating film to an upper surface of the first region.

FIELD OF THE INVENTION [0001] The present invention relates to tubular prostheses such as grafts and endoluminal prostheses including, for example, stent-grafts and aneurysm exclusion devices, and methods for placement of such grafts and endoluminal structures. Further, the present invention relates to a stent graft and deployment method. BACKGROUND OF THE INVENTION [0002] A wide range of medical treatments have been previously developed using “endoluminal prostheses,” which terms are herein intended to mean medical devices which are adapted for temporary or permanent implantation within a body lumen, including both naturally occurring or artificially made lumens. Examples of lumens in which endoluminal prostheses may be implanted include, without limitation: arteries such as those located within coronary, mesentery, peripheral, or cerebral vasculature; veins; gastrointestinal tract; biliary tract; urethra; trachea; hepatic shunts; and fallopian tubes. Various types of endoluminal prostheses have also been developed, each providing a uniquely beneficial structure to modify the mechanics of the targeted luminal wall. [0003] A number of vascular devices have been developed for replacing, supplementing or excluding portions of blood vessels. These vascular grafts may include but are not limited to endoluminal vascular prostheses and stent grafts, for example, aneurysm exclusion devices such as abdominal aortic aneurysm (“AAA”) devices that are used to exclude aneurysms and provide a prosthetic lumen for the flow of blood. [0004] One very significant use for endoluminal or vascular prostheses is in treating aneurysms. Vascular aneurysms are the result of abnormal dilation of a blood vessel, usually resulting from disease or a genetic predisposition, which can weaken the arterial wall and allow it to expand. While aneurysms can occur in any blood vessel, most occur in the aorta and peripheral arteries, with the majority of aneurysms occurring in the abdominal aorta. Typically an abdominal aneurysm will begin below the renal arteries and may extend into one or both of the iliac arteries. [0005] Aneurysms, especially abdominal aortic aneurysms, have been treated in open surgery procedures where the diseased vessel segment is bypassed and repaired with an artificial vascular graft. While considered to be an effective surgical technique in view of the alternative of a fatal ruptured abdominal aortic aneurysm, the open surgical technique suffers from a number of disadvantages. The surgical procedure is complex and requires long hospital stays due to serious complications and long recovery times and has high mortality rates. In order to reduce the mortality rates, complications and duration of hospital stays, less invasive devices and techniques have been developed. The improved devices include tubular prostheses that provide a lumen or lumens for blood flow while excluding blood flow to the aneurysm site. They are introduced into the blood vessel using a catheter in a less or minimally invasive technique. Although frequently referred to as stent-grafts, these devices differ from covered stents in that they are not used to mechanically prop open natural blood vessels. Rather, they are used to secure an artificial lumen in a sealing engagement with the vessel wall without further opening the natural blood vessel that is already abnormally dilated. [0006] Typically these endoluminal prostheses or stent grafts are constructed of graft materials such as woven polymer materials (e.g., Dacron,) or polytetrafluoroethylene (“PTFE”) and a support structure. The stent-grafts typically have graft material secured onto the inner diameter or outer diameter of a support structure that supports the graft material and/or holds it in place against a luminal wall. The prostheses are typically secured to a vessel wall above and below the aneurysm site with at least one attached expandable annular spring member that provides sufficient radial force so that the prosthesis engages the inner lumen wall of the body lumen to seal the prosthetic lumen from the aneurysm [0007] Abdominal Aortic Aneurysms are frequently treated with bifurcated devices that provide an artificial lumen for flow of blood past the aneurysm and into the iliac vessels that branch off from the aorta. One such commonly used device comprises a bifurcated device having one branch portion longer than the other branch portion. This enables deployment of the main body through one of the iliac arteries where the longer branch is deployed. An extension leg is then deployed through the second iliac artery and is connected with the shorter branch portion. [0008] Iliac vessels associated with abdominal aneurysms frequently have tortuous and twisted anatomies and other structural abnormalities that can prevent effect introduction of an extension leg through an iliac vessel. Often it must be decided prior to deployment whether to use a single lumen prosthesis through one iliac vessel and join the vessels with a shunt further down in the anatomy, or to use a bifurcated prosthesis with an extension. Often a surgeon may not be able to determine the appropriate course of action until the prosthesis is in place or after attempts have been made to deploy an extension graft through a tortuous iliac artery. It would be desirable to provide a device that would enable the decision to be made during the deployment procedure. Devices have been proposed in U.S. Pat. No. 6,102,938, incorporated herein by reference, that provide for sealing off a bifurcated portion of a bifurcated AAA device before or after deployment. Such device is designed for situations where a determination is made during a procedure that it would not be possible to introduce an extension leg into the shorter bifurcated portion to provide blood flow through one of the iliac vessels. It would be desirable to provide an improved or alternative device for accomplishing such task. [0009] Frequently, the AAA procedures are performed in emergency situations where the aorta has ruptured or is extremely fragile and about to rupture. In these situations, frequently a single leg device is deployed through the aorta and one of the iliac vessels occluding the second iliac vessel. This may be done because of the importance of reestablishing blood flow through the aorta and iliac vessel and stopping the loss of blood through the ruptured or rupturing vessel. Such situations may not permit deployment of the second (extension) leg. During this crucial time, in using an existing bifurcated device, blood would be able to flow through the shorter bifurcated portion of the prosthesis into the area of the aneurysm. Accordingly it would be desirable to provide an improved or alternative device that allows for deployment of a bifurcated device in emergency situations that would prevent further blood flow into the area of the aneurysm. SUMMARY OF THE INVENTION [0010] Accordingly one embodiment according to the present invention provides a novel device and method that include providing a bifurcated device with one leg initially in an occluded position preventing flow of blood through that portion into the aorta. Once the implant is in place and blood is excluded from the aneurysm site, an extension may be introduced and the occluded side opened to blood flow through the extension. [0011] An embodiment of the endoluminal prosthesis comprises a bifurcated tubular member constructed of a graft material and at least one annular support member. The tubular graft is formed of a woven fiber for conducting fluid. The tubular member includes, a proximal opening and distal openings though the bifurcated portions providing a lumen or lumens through which body fluids may flow. When deployed, annular support members support the tubular graft and/or maintain the lumen in a conformed, sealing arrangement with the inner wall of a body lumen. One of the bifurcated portions is provided with a valve that can open or close to permit or prevent the flow of blood through the bifurcated portion. Various embodiments of the valve includes a member that move a section of graft or other material over or away from the opening into the short iliac leg of the bifurcated prosthesis to close or open the short leg to the flow of blood. [0012] The annular support members of an embodiment of the prosthesis each comprise an annular expandable member formed by a series of connected compressible diamond structures. Alternatively, the expandable member may be formed of an undulating or sinusoidal patterned wire ring or other compressible spring member. Preferably the annular support members are radially compressible springs biased in a radially outward direction, which when released, bias the prosthesis into conforming fixed engagement with an interior surface of the vessel. Annular support members are used to create a seal between the prosthesis and the inner wall of a body lumen as well as to support the tubular graft structure. The annular springs are preferably constructed of Nitinol. Examples of such annular support structures are described, for example, in U.S. Pat. Nos. 5,713,917 and 5,824,041 incorporated herein by reference. When used in an aneurysm exclusion device, the support structures have sufficient radial spring force and flexibility to conformingly engage the prosthesis with the body lumen inner wall, to avoid excessive leakage, and prevent pressurization of the aneurysm, i.e., to provide a leak resistant seal. Although some leakage of blood or other body fluid may occur into the aneurysm isolated by the prosthesis, an optimal seal will reduce the chances of aneurysm pressurization and resulting rupture. [0013] The annular support members are attached or mechanically coupled to the graft material along the tubular graft by various means, such as, for example, by stitching onto either the inside or outside of the tubular graft. [0014] An embodiment according to the present invention provides such a tubular graft for endoluminal placement within a blood vessel for the treatment of abdominal and other aneurysms. In this embodiment, the endoluminal prosthesis is an aneurysm exclusion device forming a lumen for the flow of body fluids excluding the flow at the aneurysm site. The aneurysm exclusion device may be used for example, to exclude an aneurysm in the aorta (Abdominal Aortic Aneurysm (“AAA”) device) in which the prosthesis is bifurcated. [0015] The generally Y-shaped bifurcated tubular prosthesis has a trunk joining at a graft junction with a pair of lateral limbs, namely an ipsilateral limb and a contralateral limb. In a bifurcated prosthesis, the proximal portion of the prosthesis comprises a trunk with a proximal opening and the distal portion is branched into at least two branches with distal openings. Preferably the ipsilateral limb is longer so that when deployed, it extends into the common iliac. The contralateral limb includes a valve located therein that is initially in a closed position in which body fluids flow from the proximal opening through the distal opening of the ipsalateral limb while the flow of body fluid through the contralateral limb is prevented by the valve. A single limb extension member is provided having a mating portion for coupling with a lateral limb of a bifurcated member and an adjustable length portion extending along an axis from a distal end of the mating portion. The insertion of the limb extension into the contralateral portion of the main prosthesis opens the valve which is then in part maintained open by the extension limb, permitting blood flow from the proximal opening in the main prosthesis through the distal opening in the contralateral and extension limbs. [0016] The valve in one embodiment comprises a plurality of support members coupled to a section of graft material. One of the support members is an annular member forming an opening for the flow of body fluids. A proximal support member is a semicircular member which has an closed position in which the section of graft material forms a cover over the opening formed by the annular member, and an open position in which the section of graft material is held is a position against the wall of the prosthesis so that the opening formed by the annular member is in fluid communication with the flow of body fluid through the prosthesis. [0017] In another embodiment the valve comprises a plurality of annular support members coupled to a section of graft material where at least one of the annular support members is configured to be folded to form a semicircular member engaged to an inner circumference of the bifurcated prosthesis. When the valve is in an open position, the support members are in an open configuration whereby the annular members and a section of graft material form a lumen through which blood may flow. When the valve is in a closed position, one of the annular support members is folded to that the graft material attached to the folded annular member is drawn across the opening through the short leg in which the valve is located. [0018] In another embodiment the valve comprises a graft material sewn in part on an inner circumference of the bifurcated prosthesis and forming a pocket when the valve is closed. A portion of an annular member is sewn on to at least a portion of the section of graft material not sewn on to the prosthesis. When the valve is in a closed position, the annular member holds section of the graft material in a position over the opening in the short leg of the prosthesis. The annular member in this position is across from the location where the opposite side of the section of graft material is sewn on to the prosthesis. When the valve is in a closed position, the annular member holds the pocket formed by the section of graft material closed. The annular member in this position is against the location where the section of graft material is sewn on to the prosthesis so that the opening in the short leg provides a lumen through which blood may flow from the proximal end of the prosthesis to the distal end of the short leg. [0019] The compressed profile of the prosthesis, including the valve, is sufficiently low to allow the endoluminal graft to be placed into the vasculature using a low profile delivery catheter. The prosthesis can be placed within a diseased vessel via deployment means at the location of an aneurysm. Various means for deliver of the device through the vasculature to the site for deployment, are well known in the art and may be found for example is U.S. Pat. Nos. 5,713,917 and 5,824,041. In general, the endoluminal prosthesis is radially compressed and loaded in a catheter for delivery to the deployment site. The aneurysm site is located using an imaging technique such as fluoroscopy and is guided through a femoral iliac artery with the use of a guide wire to the aneurysm site. Once appropriately located, a sheath restraining the tubular graft may be retracted to release the annular springs to expand and attach or engage the tubular member to the inner wall of the body lumen. The iliac extension is also loaded into a catheter and is then located into the main body of the stent graft and within the iliac vessel and is placed through an opened valve where it is deployed. According to an embodiment, when deployed, the iliac has proximal annular springs which when located within the inner lumen of the main body hold or maintain the valve open. The distal portion of the extension extends into one of the iliac vessels. BRIEF DESCRIPTION OF THE DRAWINGS [0020] [0020]FIG. 1 is a side elevational view of an endoluminal prosthesis of the prior art. [0021] [0021]FIG. 2A is a side view of a valve in a closed position as positioned in a prosthesis according to an embodiment of the invention. [0022] [0022]FIG. 2B is a top cross sectional of a proximal most support member of the valve of FIG. 2A. [0023] [0023]FIG. 2C is a top cross sectional of a middle support member of the valve of FIG. 2A. [0024] [0024]FIG. 2D is a top cross sectional of a distal most support member of the valve of FIG. 2A. [0025] [0025]FIG. 2E is a front cut away view of the valve of FIG. 2A in a closed position. [0026] [0026]FIG. 2F is a back cut away view of the valve of FIG. 2A in a closed position. [0027] [0027]FIG. 3 is a top view of the prosthesis and valve of FIG. 2A. [0028] [0028]FIG. 4A is a side view of a valve of the prosthesis of FIG. 2A in an open position. [0029] [0029]FIG. 4B is a side view of the valve of FIG. 4A in an open position. [0030] [0030]FIG. 5 is a top view of the prosthesis and valve of FIGS. 4 A- 4 B. [0031] [0031]FIG. 6 is a perspective partial cutaway view of the prosthesis of FIG. 2A. [0032] [0032]FIG. 7 is perspective partial cutaway view of the prosthesis of FIG. 4A with an extension in place and the valve in an open position. [0033] [0033]FIG. 8 is a side view of another embodiment of a valve in a closed position according to the invention. [0034] [0034]FIG. 9A is a top view of the prosthesis and valve of FIG. 8. [0035] [0035]FIG. 9B is a front cut away view of the valve of FIG. 9A in an open position. [0036] [0036]FIG. 9C is a back cut away view of the valve of FIG. 9A in an open position. [0037] [0037]FIG. 10 is a side view of a valve of the prosthesis of FIG. 8 in an open position. [0038] [0038]FIG. 11A is a top view of the prosthesis and valve of FIG. 10. [0039] [0039]FIG. 11B is a side view of the valve of FIG. 11A in an open position. [0040] [0040]FIG. 12 is a side view of another embodiment of a valve in a closed position according to the invention. [0041] [0041]FIG. 13 is a perspective partial cutaway view of the prosthesis of FIG. 12. [0042] [0042]FIG. 14 is a side view of a valve of the prosthesis of FIG. 12 in an open position. [0043] [0043]FIG. 15 is perspective partial cutaway view of the prosthesis of FIG. 14. DETAILED DESCRIPTION [0044] [0044]FIG. 1 illustrates a bifurcated prosthesis of the prior art. The prosthesis 210 is shown in place in an abdominal aorta 20 . The aorta 20 is joined by renal arteries 22 and 24 at the aorto-renal junction 26 . Just below the aorta-renal junction 26 is an aneurysm 28 , a diseased region where the vessel wall is weakened and expanded. Below the aneurysm 28 , the aorta 20 bifurcates into right and left iliac vessels 21 , 23 , respectively. The elongated bifurcated tubular prosthesis 210 is deployed at the region of aneurysm 28 for the purpose of relieving blood pressure against the weakened vessel wall, by acting as a fluid conduit through the region of the aneurysm 28 . In its deployed condition, a main body portion 216 of the prosthesis 210 defines a conduit for blood flow through the aorta 20 and into the iliac vessel 21 . Before deploying an iliac extension (not shown), blood unobstructedly flows through the short iliac portion 219 into the aorta 20 as illustrated. [0045] Annular support members (rings) 212 attached to a tubular graft 25 , are designed to exert a radially outward force, sufficient to bias the tubular graft 215 of the endoluminal prosthesis 210 into conforming fixed engagement with the interior surface of aorta 20 above aneurysm 28 . The tubular graft 215 provides a leak resistant seal between the prosthesis and the inner wall of the aorta 20 . The proximal aortic portion 217 of the prosthesis 210 is located within aorta 20 , and the long ipsalateral iliac portion limb 218 is located within the right iliac vessel 21 . The short iliac portion 219 is located within the aorta 20 . The flow of blood after the main body portion 216 has been deployed is illustrated in FIG. 1. [0046] After deployment of the main body portion 216 , a contralateral iliac extension limb (not shown) may be located within left iliac vessel 23 , and near the graft junction 221 within the short iliac portion 219 . The contralateral iliac extension limb (not shown) may include a proximal support member biasing the extension into conforming fixed engagement with the interior surface of the short iliac portion 219 . [0047] To deploy the prosthesis 210 , the main body portion 216 of the prosthesis is loaded into a catheter (not shown). The main body is placed in a constrained position within a sheath or cover (not shown) of the catheter and maintains main body 216 in a compressed configuration as it is delivered to the aneurysm site. The main body portion 216 is delivered in a compressed state via catheter through a surgically accessed femoral artery, to the desired deployment site. The cover is retracted when the distal end of the catheter (not shown) is located at the deployment site, releasing the annular members 212 from the compressed position to expand into the deployed position illustrated in FIG. 1. [0048] Using a second catheter (not shown), the contralateral iliac extension limb (not shown) may be separately deployed through a surgically accessed femoral artery and into the short iliac portion 219 after placement of the main body portion 216 . [0049] FIGS. 2 A- 15 illustrate embodiments of the endoluminal prosthesis, delivery systems and methods according to the present invention. The arrows in these figures indicate the flow of blood when deployed in the corresponding configuration, within an aorta of a patient. Although an endoluminal prosthesis, delivery system and method according to the invention may be used in any bifurcated or branched body lumen that conducts body fluid, they are described herein with reference to a bifurcated device used in the treatment of an aortic aneurysm, in particular in the abdomen of a patient. [0050] FIGS. 2 A- 7 illustrate an embodiment of the invention in which a bifurcated prosthesis 50 includes a main aortic portion 52 , which splits into a long iliac portion 53 and a short iliac portion 54 . The main aortic portion 52 and the iliac portions 53 , 54 define a conduit splitting into two conduits through which blood may flow to bypass an aortic aneurysm. The prosthesis 50 comprises a tubular graft 55 and a series of radially compressible annular support members (not shown but similar to support members 212 described above with reference to FIG. 1) attached to tubular graft 55 . The annular support members support the graft and/or bias the prosthesis 50 into conforming fixed engagement with an interior surface of an aorta 20 . The annular support members are preferably spring members having predetermined radii and are preferably constructed of a material such as Nitinol in a superelastic, shape set annealed condition. The tubular graft 55 is preferably formed of a biocompatible, low-porosity woven fabric, such as a woven polyester. The graft material is thin-walled so that it may be compressed into a small space, yet capable of acting as a strong, leak-resistant, fluid conduit when in tubular form. In this embodiment, the annular support members are sewn to the outside of the tubular graft 55 material by sutures. Alternative mechanisms of attachment may be used (such as embedding or winding within material, adhesives, staples or other mechanical connectors) and the annular support members may be attached to the inside of the tubular graft 55 . [0051] A valve 60 is located adjacent or within the conduit corresponding to the short iliac portion 54 . The valve 60 has an open position (FIGS. 4 A- 4 B, 5 and 7 ) and a closed position (FIGS. 2A, 2E, 2 F, 3 and 6 ). The valve 60 includes three support members 61 , 62 , 63 generally formed of attached diamond-like structures. The distal most support member 61 (FIG. 2D) comprises an annular member in which the diamond-like structures are attached in a ring. The support members 62 (FIG. 2C) and 63 (FIG. 2B) comprise cylindrical-wall-like partial rings or semicircular members. The valve 60 may be a separate insert that is held in position within the short iliac portion 54 by the radial force of the support member 61 which may be a spring member formed e.g., of Nitinol against the inside of the short iliac portion 54 . Alternatively or in addition, the valve 60 may be attached to the inner wall of the short iliac portion 54 by suturing or other attachment means. [0052] The support members 62 , 63 may be flipped (elastically everted) from a first position forming a semicircle with an inner and outer circumference, to a second position in which the side forming the inner circumference in the first position becomes the outer circumference in the second position and the side forming the outer circumference in the first position becomes the inner circumference in the second position (the ends approximately maintaining their position to the inner wall of the short iliac leg). The support members 62 , 63 are in the first and closed position in FIGS. 2A, 2E, 2 F, 3 and 6 and are in the second and open position in FIGS. 4 A- 4 B, 5 and 7 . [0053] The support members 61 , 62 , 63 are sewn onto a section of graft material 65 . The section of graft material 65 is configured to extend around the inner circumference of the annular support member 61 forming a tube around the annular support member 61 . The section of graft material 65 is shaped or cut so that it is generally semicircular in shape where it is sewn around the support members 62 , 63 to match the shape of those members 62 , 63 . The section of graft material 65 is located on the inner circumference of the support members 62 , 63 when they are in the first, closed position, and, on the outer circumference of the support members 62 , 63 when they are in the second, open position. [0054] When in the first and closed position as illustrated in FIGS. 2A, 2E, 2 F, 3 , and 6 , the support member 61 holds the section of graft material 65 in place around the circumference of the lumen in the short iliac portion 54 of the prosthesis 50 where it forms a lumen 66 . The support members 62 and 63 hold the section of graft material 65 in a position over the lumen 66 forming a cover 67 (FIG. 3) that prevents the flow of blood through the lumen 66 or the short iliac portion 54 . The proximal most support member 63 holds a portion 65 a of a section of the graft material 65 against a first portion 55 a of an inner circumference of the tubular graft 55 . (FIGS. 2E, 2F) The support member 62 located between support members 61 and 63 provides a transition for the section of the graft material 65 across the lumen 66 to provide the cover 67 (FIGS. 2E, 2F). [0055] The support members 62 and 63 are flipped (elastically everted) over into the second, open position as illustrated in FIGS. 4 A- 4 B, 5 and 7 . In this position, the graft material 65 surrounding the support members 62 , 63 that in the first position formed the cover 67 , is held in position against the inner wall (i.e., a second portion 55 b of an inner circumference of the tubular graft 55 opposite from the first portion 55 a of the inner circumference) of the short iliac portion 54 of the prosthesis 50 so that it does not interfere with the flow of blood through the lumen 66 . [0056] In one embodiment the prosthesis 50 is deployed as follows. The valve 60 is initially in a closed position and the prosthesis 50 is loaded into a catheter 80 . The prosthesis 50 along with the valve 60 may be radially compressed within a delivery catheter 80 . The catheter 80 is located in position to deploy the prosthesis in the abdominal aorta of a patient with an aneurysm in the aorta (not shown) below the aortarenal junction (not shown). The prosthesis is deployed by retracting a sheath that is holding the prosthesis 50 in its radially compressed position. [0057] Surgical methods and apparatus for accessing the surgical site are generally known in the art and may be used to place the catheter within the vasculature and deliver the prosthesis to the deployment site. Additionally, various actuation mechanisms for retracting sheaths of catheters are known in the art. The prosthesis 50 may be delivered to the deployment site by one of several ways. A surgical cut down may be made to access a femoral iliac artery. The catheter 80 is then inserted into the artery and guided to the aneurysm site using fluoroscopic imaging where the prosthesis 50 is then deployed. The members 51 supporting the graft 55 , biased in a radially outward direction, are released to expand and engage the prosthesis 50 in the vessel against the vessel wall to provide an artificial lumen for the flow of blood. Another technique includes percutaneously accessing the blood vessel for catheter delivery, i.e., without a surgical cutdown. An example of such a technique is set forth in U.S. Pat. No. 5,713,917, incorporated herein by reference. [0058] When deployed, the prosthesis 50 is in position with the aortic portion 52 engaging the neck region just below the renal arteries 22 , 24 . The long iliac portion 53 is located within the iliac vessel 21 while the short iliac portion 54 is within the aorta 20 just proximal of the iliac vessel 23 as illustrated in FIG. 2A, 3 and 6 . [0059] Referring to FIG. 7, a catheter 80 has been inserted through the iliac vessel 23 in a manner that is typically used to deploy an extension graft, and the extension member 68 has been deployed. In inserting the catheter 80 , the tip 81 of the catheter 80 is first inserted by guiding it between the inner wall of the short iliac portion 54 and the outer circumference of the support members 62 , 63 in their closed position. The tip 81 of the catheter 80 is tapered so that as it is inserted, it flips the support members 62 , 63 into the second position, opening the valve 60 . The support members 62 , 63 demonstrate an over center spring action whereby they are stable in both the closed and open valve positions illustrated in FIGS. 2 A- 7 . Once the support members 62 , 63 are moved over a center, they will move to the opposite position. [0060] Once the support member 62 , 63 are moved from the closed valve position to the open valve position, the extension member 68 that is loaded in the catheter 80 is released from the catheter 80 in a position in which at least a portion of the extension member 68 is located within the lumen 66 in the open valve 60 and maintains the valve 60 in an open position with the radial force exerted by support members 69 on the extension member 68 (as shown in FIG. 7). The extension member 68 extends into the iliac artery and forms a lumen for the flow of blood therethrough. The support members are constructed of a Nitinol that is preset to maintain a closed configuration so in the absence of an opening force, the valve will close [0061] According to this embodiment, the valve 60 is initially in a closed position when the prosthesis 50 is deployed. Thus, flow of blood into the aneurysm through the short iliac portion or leg 54 is prevented until an extension member 68 is placed the second iliac artery 23 and into the short iliac portion 54 . The valve 60 thus will remain closed if the surgeon determines that it is not feasible or desirable to deploy an extension member through the iliac vessel 23 . [0062] FIGS. 8 - 11 B illustrate another embodiment according to the invention in which a bifurcated prosthesis 110 includes a main aortic portion 112 , which splits into a long iliac portion 113 and a short iliac portion 114 . The main aortic portion 112 and the iliac portions 113 , 114 define a conduit splitting into two conduits through which blood may flow to bypass an aortic aneurysm. The prosthesis 110 comprises a tubular graft 115 and a series of radially compressible annular support members (not shown but similar to support members 212 described above with reference to FIG. 1) attached to tubular graft 115 . The annular members support the graft and/or bias the prosthesis 110 into conforming fixed engagement with an interior surface of an aorta (not shown). The annular support members are preferably spring members having predetermined radii and are preferably constructed of a material such as Nitinol in a superelastic, shape set annealed condition. The tubular graft 115 is preferably formed of a biocompatible, low-porosity woven fabric, such as a woven polyester. The graft material is thin-walled so that it may be compressed into a small diameter, yet capable of acting as a strong, leak-resistant, fluid conduit when in tubular form. In this embodiment, the annular support members are sewn on to the outside of the tubular graft 115 material by sutures. Alternative mechanisms of attachment may be used (such as embedding or winding within material, adhesives, staples or other mechanical connectors) and the annular support members may be attached to the inside of the tubular graft 115 . [0063] A valve 120 is located adjacent or within the conduit corresponding to the short iliac portion 114 . The valve 120 has an open position (FIGS. 10, 11A and 11 B) and a closed position (FIGS. 8 and 9A- 9 C). The valve 120 includes three support members 121 , 122 and 123 comprising attached diamond-like structures formed into rings. The valve 120 may be held in position within the short iliac portion 114 by the radial force of the distal most support member 121 which may be a spring member formed e.g., of Nitinol. Alternatively or in addition, the valve 120 may be attached in part to the inner wall of the short iliac portion 114 , for example, by suturing or other mechanical means. [0064] The support members 121 , 122 , 123 are sewn onto section of a graft material 125 . The graft material 125 extends around the inner circumference of the annular support members 121 , 122 , 123 forming at tube around the inner circumference of the annular support members 121 , 122 , 123 . [0065] The support members 122 , 123 may be flipped (elastically everted) from a first position in which the support members are folded into semicircular configurations (wherein each ring forming a support member ( 122 , or 123 ) are folded into two folded halves), to a second position in which the support members 122 , 123 are opened into ring configurations. The support members 122 , 123 are in the first and closed position in FIGS. 8 and 9A- 9 C and are in the second and open position in FIGS. 10, 11A and 11 B. [0066] When in the first and closed position as illustrated in FIGS. 8 , and 9 A- 9 C, the support member 121 holds the section of the graft material 125 in place around the circumference of the lumen in the short iliac portion 114 of the prosthesis 110 where it forms a lumen 126 . The support members 122 and 123 are folded so that the outer side of a portion 125 b of the section of the graft material 125 is held in a position over the lumen 126 , thus forming a cover 127 that prevents the flow of blood through the lumen 126 or the short iliac portion 114 . The proximal most support member 123 holds a portion 125 a of a section of the graft material 125 against an inner circumference of a portion of the valve 120 that is held against a first portion 115 a of the inner circumference of the short iliac portion 114 of the tubular graft 115 (FIGS. 9B, 9C). The support member 122 located between support members 121 and 123 provides a transition for the section of the graft material 125 across the lumen 126 to provide the cover 127 (FIGS. 9B, 9C). [0067] The support members 122 and 123 are flipped over into the second, open position as illustrated in FIGS. 10, 11A and 11 B. In this position, the portion 125 a of the section of the graft material 125 surrounding the support members 122 , 123 that in the first position formed the cover 127 , is in tubular configuration, in which the section of the graft material 125 is held against the inner wall of the short iliac portion 114 of the prosthesis 110 so that it does not interfere with the flow of blood through the lumen 126 . The prosthesis 120 in the open position, as illustrated in FIG. 11B, extends partially proximally of the inner wall of the graft junction 121 within the short iliac portion 119 that divides the short iliac portion 119 from the long iliac portion 118 . [0068] The prosthesis 110 is deployed in a manner similar to the prosthesis 50 described above with reference to FIGS. 2 A- 7 . The valve 120 is initially in a closed position and the prosthesis 110 is loaded into a catheter (not shown). The prosthesis 110 along with the valve 120 may be radially compressed within a delivery catheter and is positioned and deployed in the abdominal aorta of a patient. According to this embodiment, the valve 120 is initially in a closed position when the prosthesis 110 is deployed. Thus, flow of blood into the aneurysm through the short iliac portion or leg 114 is prevented until an extension member (not shown) is placed through the second iliac artery (not shown) and into the short iliac portion 114 . The valve 120 thus will remain closed if the surgeon determines that it is not feasible or desirable to deploy an extension member through the iliac vessel. [0069] An extension graft (not shown) is deployed in a manner similar to the deployment of the extension member 68 described above with reference to FIG. 7. Accordingly, the tip of a catheter into onto which the prosthesis 110 is loaded (not shown) is guided between the folded portions 122 a , 122 b of the support member 122 in its closed configuration, and the folded portions 123 a , 123 b of the support member 123 in its closed configuration. The tip of the catheter is tapered so that as it is inserted, it opens the support members 122 , 123 into the second positions, opening the valve 120 . The extension member that is loaded in the catheter is then released from the catheter in a position in which at least a portion of the extension member is located within the lumen 126 in the open valve 120 and maintains the valve 120 in an open position with the radial force exerted by the extension member. The extension member extends into the iliac artery and forms a lumen for the flow of blood therethrough. The support members 122 , 123 are constructed of a similar material as support members 61 , 62 , and 63 , described above with reference to FIGS. 2 A- 7 . [0070] FIGS. 12 - 15 illustrate an embodiment of the invention in which a bifurcated prosthesis 150 includes a main aortic portion 152 , which splits into a long iliac portion 153 and a short iliac portion 154 . The main aortic portion 152 and the iliac portions 153 , 154 define a conduit splitting into two conduits or lumens through which blood may flow to bypass an aortic aneurysm including lumen 156 through the short iliac portion 154 . The prosthesis 150 comprises a tubular graft 155 and a series of radially compressible annular support members (not shown, but similar to support members 212 described herein with reference to FIG. 1) attached to tubular graft 155 . The annular members 151 support the graft and/or bias the prosthesis 150 into conforming fixed engagement with an interior surface of an aorta. The annular support members are preferably spring members having predetermined radii and are preferably constructed of a material such as Nitinol in a superelastic, shape set annealed condition. The tubular graft 155 is preferably formed of a biocompatible, low-porosity woven fabric, such as a woven polyester. The graft material is thin-walled so that it may be compressed into a small diameter, yet capable of acting as a strong, leak-resistant, fluid conduit when in tubular form. In this embodiment, the annular support members are sewn on to the outside of the tubular graft 155 material by sutures. Alternative mechanisms of attachment may be used (such as embedding or winding within material, adhesives, staples or other mechanical connectors) and the annular support members may be attached to the inside of the tubular graft 155 . [0071] A valve 160 is located adjacent or within the lumen 156 of the short iliac portion 154 . The valve 160 has an open position (FIGS. 14 and 15) and a closed position (FIGS. 12 and 13). The valve 160 comprises a support member 161 sewn onto a section of graft material 165 shaped in the form of a pocket. The support member 161 comprises attached diamond-like structures formed into a semicircular member and is sewn onto the top edge of the pocket-shaped section of graft material 165 . The support member 161 is constructed of a similar material as support members 61 , 62 , and 63 , described above with reference to FIGS. 2 A- 7 . The support member 161 has a first position corresponding to the first and closed position of the valve in which the support member is in sealing engagement with a portion of the inner circumference of the tubular graft 155 of the prosthesis 150 . The support member 161 has a second position corresponding to the second and open position of the valve 160 where the support member 161 is in sealing engagement with a second portion of an inner circumference of the tubular graft 155 , the second portion being on a opposite side of the tubular graft from the first portion. A portion of the section of graft material 165 is secured, e.g., sewn, onto the inner wall of the short iliac portion 154 that forms the lumen 156 , i.e. to the second portion of the inner circumference of the tubular graft 155 , so that the portion of the section of graft material provides a leak resistant seal with the inner wall of the tubular graft 155 . The graft material 165 , when the valve 160 is in the first and closed position as illustrated in FIGS. 12 , and 13 , forms a cover 167 over the lumen 156 in the short iliac portion 154 of the prosthesis 150 that prevents the flow of blood through the lumen 156 . The graft material 165 extends around the inner circumference of the annular support members 161 so that graft material 165 and the support structure 161 when in the closed position, form a leak resistant seal with the inner wall of the short iliac portion 154 . In addition to attaching the graft 165 to the inner wall of the short iliac portion 154 , the valve 160 is held in position within the short iliac portion 154 by the radial force of the support member 161 which may be a spring member formed e.g., of Nitinol. The support member 161 holds the valve 160 in the first and closed position in FIGS. 12 and 13 and in the second and open position in FIGS. 14 and 15. [0072] The support member 161 may be flipped from a first position in which the valve 160 is closed, to a second position in which the valve 160 is open. In the first position, the support member forms a semicircle with an inner and outer circumference. When it is in its second position, the side forming the inner circumference in the first position becomes the outer circumference in the second position and the side forming the outer circumference in the first position becomes the inner circumference in the second position. When the support member 161 is flipped over into the second, open position as illustrated in FIGS. 14 and 15 the graft material 165 surrounding the support member 161 that in the first position formed the cover 167 , and the graft material 165 that is attached to the inner wall of the short iliac portion 154 , is held by the support member 161 against the inner wall of the short iliac portion 154 of the prosthesis 150 so that it does not interfere with the flow of blood through the lumen 156 . The graft material 165 is located on the inner circumference of the support member 161 when it is in the first, closed position, and, on the outer circumference of the support member 161 when it is in the second, open position. [0073] The prosthesis 150 is deployed in a manner similar to the prosthesis 50 described above with reference to FIGS. 2 A- 7 . The valve 160 is initially in a closed position and the prosthesis 150 is loaded into a catheter (not shown). The prosthesis 150 along with the valve 160 may be radially compressed within a delivery catheter and is positioned and deployed in the abdominal aorta of a patient. Thus, flow of blood into the aneurysm through the short iliac portion or leg 154 is prevented until an extension member (not shown) is placed through the second iliac artery (not shown) and into the short iliac portion 154 . The valve 160 thus will remain closed if the surgeon determines that it is not feasible or desirable to deploy an extension member through the iliac artery. [0074] An extension graft (not shown) is deployed in a manner similar to the deployment of the extension member 68 described above with reference to FIG. 7. Accordingly, the tip of a catheter into onto which the prosthesis 150 is loaded (not shown) is guided between the inner wall of the short iliac portion 154 and the outer circumference of the support member 161 in its closed position. The tip of the catheter is tapered so that as it is inserted, it flips the support member 161 into the second position whereby the support member 161 holds the graft material 165 in a position against the inner wall of the short iliac portion so that the valve 160 is open and the graft material 165 does not obstruct the flow of blood through the short iliac portion 154 . The extension member that is loaded in the catheter is then released from the catheter in a position in which at least a portion of the extension member is located adjacent the support member 161 and maintains the valve 160 in an open position with the radial force exerted by the extension member. The extension member extends into the iliac artery and forms a lumen for the flow of blood therethrough. [0075] While the invention has been described with reference to particular embodiments, it will be understood to one skilled in the art that variations and modifications may be made in form and detail without departing from the spirit and scope of the invention.

A bifurcated endoluminal prosthesis is provided that includes a valve or gate in one of the bifurcated branches. The valve or gate prevents flow of blood through the branch when it is closed and permits the flow of blood when it is open. In one variation, the valve comprises a spring member attached to a graft material substantially impermeable to the flow of blood. The spring member holds the graft material over the opening that forms a lumen in the bifurcated portion. The spring member may be flipped from a closed position in which it is initially deployed, to an open position whereby the graft material forms an opening continuous with lumen in the bifurcated portion permitting the flow of blood therethrough. The invention may be used in bifurcated or branched tubular grafts for endoluminal placement within a body lumen, including blood vessels, and for the treatment of abdominal and other aneurysms.

[0001] This application claims the benefit of U.S. Provisional Application No. 60/258,494, filed Dec. 29, 2000. BACKGROUND OF THE INVENTION [0002] Silica powders are used in the production of silica glass products such as optical windows, scintillators and optical filters. [0003] Fine control of the processes is required to produce end products with desired characteristics. Variations in characteristics result in products with little or no economic value. [0004] Needs exist for better starter materials to ensure uniformity of products. SUMMARY OF THE INVENTION [0005] Silica grains of desired sizes and desired compositions and doping for use as starter materials in silica products are produced using the present invention. [0006] According to the invention, silica powders are introduced or created in a vacuum chamber. [0007] A gas or gases plasma heats the powders rendering them sticky. The surfaces melt and the powder particles agglomerate and fuse into larger particles as they pass through the plasma. [0008] Microwave/electron cyclotron resonance (MW-ECR) or other methods for generating plasma may be introduced in the chamber. Argon, nitrogen, ammonia, oxygen and other gasses may be used for the plasma. One or more sources producing the same or different gas plasma may be coupled with the same chamber. The plasma ports all may be directed at the same chamber section, or they may be cascaded in specific orders. Each chamber may contain one or more plasma generators resulting in certain plasma density. Such chambers may form a cascade. Fused silica grains traveling through the cascade may experience increase or decrease in temperature. The same vacuum or different vacuums may be present at each plasma port. The plasma ports may be within one chamber or they may be in separate chambers. Chambers may be separated or not separated by gate valves. Plasma chamber cascades may be employed to achieve the desired grain properties. The plasma flow may consist of pure plasma, plasma and carrier gas, or plasma and neutral gas. The plasma may have, plasma and any mixture of neutral gases. The plasma density and temperature may be adjusted to fit the grain size of the fused silica introduced in the chamber in order to obtain certain desired grain size, grain size distribution and OH content. [0009] Microwave electron cyclotron resonance plasma (MW-ECR) sources, among any other plasma generators may be used for production of synthetic fused silica grain of desired size or for processing of natural quartz powder into powder with certain grain size and quality. The plasma source used will allow for clean, temperature and density controlled stream of plasma that will allow for controlling the fused silica or natural quartz grain temperature for certain periods of time. [0010] Synthetic fused silica powder may be introduced in the chamber as powder, powder and plasma mix, powder obtained via pyrolisis of silicon tetrachloride, silicon tetra fluoride, organosilicate compounds, and other silicon based compounds, organic or inorganic. When subjected to heat, plasma stream, EM field or other methods suitable for this purpose the powder will result in fused silica particles having the desired purity, OH content and particle size distribution. [0011] Ion temperatures in the vicinity of 1 eV and electron temperatures between 4-7 eV may be used. The density of the plasma (˜10 10 cm −3 ) and its temperature are determined by the plasma source array and the placement of each plasma generator and they will determine the temperature of the silica grain and how much it will fuse into larger grains of silica. A plasma exposure cascade may further enhance the grain size to the desired grain volume or grain weight. Heating individual grains to such high temperatures before the fusion and after the fusion and possibly repeating this process within a cascade of plasma exposure eliminates OH group presence in the fused silica and the reaction with various gases in plasma or neutral state can further purify the silica grain and the soot produced from the same. Repeat of the silica grain with plasma/neutral gas interaction, and the appropriate time length for the contact will determine the appropriate temperature of the reaction taking place and the fusion between different grains into grains having desired grain size and purity. Reactive plasma such as atomic chlorine, fluorine and other ions may be used to remove certain impurities in the fused silica grain. [0012] Dopant may be introduced in gaseous, liquid or solid state for doping of the grains while they are fusing or as a later step in the fused silica processing. [0013] Additional grain heating by means of resistive, RF or any other heating methods may be used. Multi zone heating arrangement in the chamber may be applied for this purpose. Equilibrium chamber vacuum or differential vacuum may be present during the synthetic fused silica or natural quartz grain processing. [0014] The so purified material can remain in granular state, or it can be deposited on a bait that can be made of quartz, graphite, silicon carbide, ceramic, metal or metal alloy that possesses any porosity: from very porous to solid material. The bait can have any desired shape and cross section to better suit the step processing of the fused silica. [0015] In one embodiment synthetic fused silica or natural quartz powder may be introduced simultaneously. The plasma heated powder jets from plurality of ports enter the chamber and they are “contained” within certain elliptically shaped cloud. Other plasma for additional grain heating and purification may be introduced in the particle cloud. Reactive gasses in plasma or neutral state may also be introduced in the particle cloud for purification or other purposes. [0016] The grains collide among themselves forming larger grains. The high temperature of the grain provides for removal of the OH content in the grain. The high temperature of the grain and the reactions the grain is subjected to in the particle cloud or in the chamber in general provides for removal of various trace elements that are pumped out in gaseous form. [0017] Such produced grain may be subjected to a cascade of individual or interconnected chambers that further contribute to the grain size, grain size distribution and grain purity. [0018] In another embodiment the powder is deposited in a tray that can be heated. Synthetic fused silica or natural quartz having desired purity, OH content and grain size distribution is obtained. This powder can further be used in various processes for fabrication of fiber optic preforms, synthetic fused silica, natural quartz or their combination made into tubes for modified chemical vapor deposition (MCVD), for fabrication of fiber optic preforms, doped or undoped cores for axial vapor deposition methods, for fiber optic preforms fabrication, solid rods and plate shaped members for semiconductor wafers and optical components fabrication. [0019] These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the claims and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0020] FIGS. 1 - 16 discuss different embodiments for the synthetic fused silica fabrication, applications and products made by the same. [0021] [0021]FIG. 1 show forming of fused silica grains from powder particles. [0022] [0022]FIG. 2 shows collecting, treating and processing the fused silica grains. [0023] [0023]FIG. 3 adds electrodes and an electric field to the softened fused silica. [0024] [0024]FIG. 4 shows double crucible used in the process. [0025] [0025]FIG. 5 shows direct plate or bar formation. [0026] [0026]FIG. 6 is a schematic perspective representation of a porous preform-general chamber, which may be horizontal, vertical or any other position. [0027] [0027]FIG. 7 shows a cross-sectional view of the chamber shown in FIG. 1, in which one or a plurality of deposition rods made from carbon, SiC, ceramic or graphite may be rotated to collect the glass soot. [0028] [0028]FIG. 8 shows spacing of plural preforms in a chamber. [0029] [0029]FIG. 9 shows multiple preforms with rotation and translation in the silica grain streams in the chamber. [0030] [0030]FIG. 10 shows dopant gas distribution to and through the preform. [0031] [0031]FIG. 11 shows rotating and translating the preform of in powder streams and forming a cladding layer. [0032] [0032]FIG. 12 shows vitrifying and densifying a cladding layer on a core. [0033] FIGS. 13 A- 13 D show transforming a tubing into a solid member. [0034] [0034]FIGS. 14A and 14B show transforming a tubing into a solid member. [0035] [0035]FIGS. 15A and 15B show vitrifying a silica tube and the product produced. [0036] [0036]FIG. 16 schematically shows forming a plate or bar from a tubular or rod preform formed from fused silica grains. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0037] [0037]FIG. 1 shows a chamber 300 with burners 3 and small grain silica powder introduction ports 37 . The burners 3 create fine silica powder from precursor materials and heat the plasma 311 . A differential reduced pressure 301 is drawn on the chamber using valved vacuum line 303 . A valved gas inlet 305 provides dopant gas and inert gas. A valved vent 307 removes combustion gasses and excess dopant gas. Microwave electron cyclotron resonance heaters 309 create the high temperature plasma 311 . The fine grain silica powders pass through the plasma and are heated and softened. The hot soft surfaces of the fine grain powder particles cause agglomeration and fusing of the powder particles into large grain silica particles. Uniform grain size is created, and OH content is reduced or eliminated. The plasma fields are controlled so that surface melting of the increasing size particles is maintained in the plasma. The plasma 311 contains multiple heat zones. Multizone resistance or radio frequency (RF) heaters 309 may be used to maintain temperatures in plasma fields 311 . The fused particles are collected in a heated rotating tray 313 which is rotated clockwise or counter clockwise or in alternating directions and elevated and lowered as sho9en by arrows with a turning and elevating device 314 . [0038] The first chamber produces silica and other soot of desired size. The vacuum chamber has plurality of vacuum ports, gas inlet ports, vent ports, reactive burners, and silica powder delivery ports. The chamber is heated by resistance or RF heating, plasma heating or any other mean of heating, connected through plurality of feedthroughs. Crucible made from graphite, silicon carbide, ceramic material, metal or metal alloys receives the material. The vacuum chamber can be multiple chambers. [0039] [0039]FIG. 2 shows a chamber 183 for producing silica powder 185 and other metal oxides from burners 3 and from soot 187 introduced from ports and agglomerated in plasma 189 into grains having desired particle size. Fine oxide particles, in suit made from burners 3 or delivered through plurality of ports 37 on the chamber are heated in plasma 189 and allowed to recombine. The plasma 189 is created by hot temperatures produced in inert gases by heating in a multizone arrangement. Depending on the time the particles stay hot and the distance the particles travel, they recombine into larger grains of desired size. The vacuum chamber 183 has multizone heating zones Z1-Z6 with heaters 184 . Microwave electron cyclotron resonance heating, in zones Z1, Z2 and Z3 of increasing temperatures, resistive heating, RF heating of the plasma 189 or other heating methods of the grains may be employed. [0040] The soot is collected in a crucible 191 . A heater 193 in zone Z4 keeps the sized grains hot in crucible 191 . The hot grains are doped using a dopant injector 195 , as shown in FIG. 2. The grains 185 may be melted 196 , funneled and flowed around a former 197 and filled with an inert gas with a dopant 199 or an inert gas 199 to form a tube 201 . Tube 201 passes out of chamber 183 through a gate 202 after solidification in zone Z6 in which temperatures are maintained by heaters 198 . [0041] The vacuum chamber having plurality of vacuum ports, gas inlet ports, vent ports, reactive burners, and silica powder delivery ports. The chamber is heated by resistance heating, RF heating, plasma heating or any other means of heating connected through plurality of feedthroughs. A funnel made from graphite, silicon carbide, ceramic material, metal or metal alloys receives the material. The material is softened in the funnel and transformed into a fused quartz article of choice. The fused silica article can rotate clockwise or counterclockwise. This material can feed into a fabrication apparatus. [0042] Another chamber employing the new soot grain enlargement process for tube or rod fabrication is as shown in FIG. 3. In that embodiment electric field generator 177 with electrodes 179 and 181 provides an electric field across the softened fused silica flow 125 . Electrode 179 is located within the softened bubble 125 which forms tube 201 . Electrode 181 is located outside the bubble 125 . A plasma tube surface removal unit 204 cleans the surface of the tube in a hot plasma. [0043] [0043]FIG. 4 shows a double crucible 203 in the chamber. A vacuum chamber 183 having plurality of vacuum ports, gas inlet ports, vent ports, and a fused silica feed material introduction port is heated by resistance or RF heating or any other means of heating, connected through plurality of feedthroughs. A second crucible 203 made from graphite, silicon carbide, ceramic material, metal or metal alloys receives, holds and melts the material from the feed crucible 191 , softens the same and remelts the material. A dopant gas from tube 195 is added to the molten material in crucible 203 . A fused silica tube is produced. Pluralities of ultrasound generators 206 are in contact with the crucible to provide proper mixing and outgassing. Additional vacuum ports are placed above the softened material to remove any gas bubbles. The chamber can be a single chamber or plurality of chambers. [0044] [0044]FIG. 5 shows a plate or bar forming chamber 211 in which the infeed is a tube 201 or rod. The plate or bar forming chamber 211 directly coupled to chamber 183 for receiving the fused silica tube input 217 directly from the output of chamber 183 . The plate/bar fabrication chamber 211 has two separated chambers. A vacuum chamber 213 having plurality of valved vacuum ports 221 , gas inlet ports 223 , vent ports 225 and a fused silica feed material 217 introduction port 227 is heated by resistance of RF heating 219 or any other means of heating, connected through a plurality of feedthroughs. A crucible 230 made from graphite, silicon carbide, ceramic material, metal or metal alloys receives the material 231 from the feed tube 217 , softens, dopes, degasifies and solidifies the material. A fused silica plate or a bar 210 is produced. A plurality of ultrasound generators 233 are in contact with the crucible to promote proper mixing and outgassing. Additional vacuum ports 235 are placed above the softened material to remove any gas bubbles. The chamber can be a single chamber or plurality of chambers 213 , 215 with sequentially controlled heat zones. [0045] The plate/bar fabrication chamber is a vacuum chamber having plurality of vacuum ports, gas inlet ports, and vent ports. A fused silica feed material introduction port is heated by microwave, resistance, RF heating, or any other means of heating, connected through plurality of feedthroughs. A crucible made from graphite, silicon carbide, ceramic material, metal or metal alloys receives the material form the feed rod, softens the same and solidifies the material. A fused silica plate or a bar is produced. Plurality of ultrasound generators are in contact with the crucible to promote proper mixing and outgassing. Additional vacuum ports are placed above the softened material to remove any gas bubbles. The chamber can be a single chamber or plurality of chambers. [0046] [0046]FIGS. 6 and 7 show a plurality of substrates 11 with controlled temperature housed in a vacuum chamber 1 . A plurality of burners 3 for oxidation 5 of metal halides 7 such as SiCl4, SiF4 and others are either imbedded in the chamber wall 8 or they are placed inside the chamber. The proximity of the burners to the substrates 11 as well as the distance of the substrates from the center 9 of the chamber are optimized based on the number of the substrates 11 , the number of the burners 3 and their relative positions. The chamber 1 may have round, rectangular or any other suitable shape that is needed to optimize the process. Vacuum ports 13 with valves 15 , vents 17 with valves 19 and a plurality of gas inlet ports 21 with valves 23 are also added to the chamber. The chamber may be vertical, horizontal, sloped and any other position or combination suitable for the new process. The chamber walls 8 may have a cooling jacket 25 for temperature control and appropriate venting apparatus for the gasses generated during the deposition. Appropriate openings are provided at one end, at each end or on one or two sides of the chamber for loading and unloading of the chamber. [0047] A plurality of power feeds for resistive heating 29 or RF coils 31 and appropriate power feedthroughs 33 and shields 35 are also included in the chamber. [0048] The chamber may have plurality of ports 37 for introduction of soot 39 made during another operation. [0049] The chamber and the substrate assembly may be rotated in respect to each other clockwise or counterclockwise at certain desired speeds. Each substrate may be rotated around its axis clockwise or counterclockwise at certain desired speeds. All rotations are aimed at establishing conditions for good thickness and uniformity properties of the deposited material in the porous perform 41 . [0050] [0050]FIG. 9 shows a tubular substrate 11 with deposited material 43 . Each substrate 11 may be made of solid, porous or perforated material made from graphite, silicon carbide, ceramic, metal or metal alloys. It may have round, rectangular or any other cross section. It may be tubular, solid or tubular with solid core made from the same or other material. The ends 45 may have the same cross section throughout, or the ends may have different dimensions or shapes. The ends 45 may be mechanically connected to the substrate 11 or they may be part of the substrate. A gas line 47 or vacuum line may be connected with the hollow portion of each substrate having tubular shape, with or without a central rod. [0051] [0051]FIG. 10 shows an apparatus consisting of a vacuum chamber 51 having plurality of vacuum ports 53 , vent lines 55 , and gas ports 57 doping ports 59 for purging and doping purposes, plurality of power feedthroughs 61 with or without cooling lines 63 in them for resistive, RF 65 or any other form of heating the substrate 11 of the preform 41 and the preform itself. The chamber may have multiple heating zones 67 to accommodate the process being performed there. Rotation and translation mechanisms 60 rotate 62 and translate 64 the substrate 11 and preform 41 . Slip rings 66 conduct power from source 68 to heat the substrate 11 . [0052] In FIG. 10 the dopant gases 58 surround the preform 41 , and purge or dopant gases 56 from purge or dopant line 54 flow outward from the porous substrate through the porous preform 41 . [0053] As shown in FIG. 11, a doped or undoped cladding layer 77 may be added to a doped or undoped preform core silica deposit 75 . Several preforms 41 may be constructed at the same time using the independent rotation mechanism and support 70 . [0054] As shown in FIG. 12, the core-forming silica layer 75 may be vitrified 76 initially before deposition of the cladding layer 77 , followed by vitrification 78 of the cladding layer, all within the single chamber 51 . The independent rotation mechanism 70 permits deposit and vitrification of layers on multiple preforms concurrently. [0055] [0055]FIGS. 13A and 13B show cross-sections of tube-shaped preforms 41 with a hole 81 , an inner tubular layer 83 , and an outer tubular layer 85 . Supporting the preform 41 between ends, heating the preform to softening temperature and rotating the preform shrinks the preform to the solid member 86 with a solid core 87 and cladding 89 , as shown in FIGS. 13C and 13D. [0056] [0056]FIG. 15A shows a vitrified silica tube 90 in a chamber 51 . The vitrified tube 90 is removed from the chamber, as shown in FIG. 15B. Detaching the independent rotation mechanism from support ends 45 allows the substrates to be detached from the mechanism 70 . Alternatively, the mechanism may be left in place on the support 45 while the individual substrates 11 are removed. [0057] When the substrate is fused silica, the tube is ready to be used or ready to be softened and to be compacted and densified into a solid. [0058] Alternatively, the substrate 11 may be heated, and the fused silica tube 90 may be slid off the substrate after a film is melted adjacent the substrate, after the ends 91 are removed as shown in FIGS. 12A and 12B. [0059] The tubing 90 that is removed has a hole 93 and a tube wall 95 , as shown in FIG. 13A, before it is compressed into a solid doped fused silica rod 97 , as shown in FIG. 13B. [0060] [0060]FIGS. 14A and 14B show fusing a doped fused silica tubing 90 to a doped fused silica rod 97 . [0061] [0061]FIG. 16 shows a plate/bar fabrication chamber 211 . A vacuum chamber 213 having plurality of valved vacuum ports 221 , gas inlet ports 223 , vent ports 225 and a fused silica feed material 217 from introduction port 227 is heated by resistance or RF heating 219 or any other means of heating, connected through a plurality of feedthroughs. A crucible 230 made from graphite, silicon carbide, ceramic material, metal or metal alloys receives the material 231 from the feed tube 217 , and softens, dopes, degasifies and solidifies the material. A fused silica plate or a bar 210 is produced. A plurality of ultrasound generators 233 are in contact with the crucible to prevent proper mixing and outgassing. Additional vacuum ports 235 are placed above the softened material to remove any gas bubbles. The chamber can be a single chamber or plurality of chambers 213 , 215 with sequentially controlled heat zones. [0062] [0062]FIG. 16 also shows a plate or bar forming chamber 211 in which the infeed 217 is a solid rod. [0063] The heating of the substrate may be accomplished by separate heaters positioned axially along or in the substrate. Alternatively if resistance heating is used, the heating wire may be varied in shape, form or size along the length of the substrate. The substrate may be linear or planar and may be made in one element or plural elements. A singe control or multiple independent controls may be used. The varied heating of the substrate may be used to effect uniformity of the preform in an axial direction. Alternatively the varied heating may be used to effect varied densities or porosities of the perform along it's length or per unit area. EXAMPLES [0064] Silica Glass Body Fabrication [0065] Production of synthetic fused silica glass bodies having controlled density and desired size and shape have been of interest to the natural quartz or synthetic fused silica glass industry for some time. The densities of the formed silica body mainly depend on the temperature of the flame, the distance between the substrate and the burner, and rotational and translational speeds of the substrate. Densities between 10% and 30% have been reported by this approach. The size of the body and the optimal ratio between the wall thickness (W t ) and the outside diameter (D o ), Wt/D o , as well as the ratio between the outside diameter (D o ) and the Inside diameter (D i ), D o /D i , and the way the body is held during the deposition depend greatly on the density of the body surface temperature and the body density. [0066] To overcome the current limitations and to produce large glass bodies made from synthetic fused silica, natural quartz or combination thereof, substrate heating and surface heating has been introduced. The amount of the surface heating will greatly depend on the substrate temperature, the chamber pressure, the size of the quartz particles and their temperature at impact of the surface and the size of the quartz member fabricated. Silica preforms, doped or undoped, having desired density and optimized diameter ratio can be fabricated following the examples shown below. Example No. 1 Silica Body Fabrication [0067] A heated substrate having temperature of about 1000°-1400° C. is subjected to plurality of silica particle stream either generated in situ by high temperature reactions of silica precursors, or fabricated in a separate process and then introduced via ports on the chamber in pure form, doped form, mixed with neutral gas, gas plasma or combination thereof. The so accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited, and layer by layer the silica member is formed. The silica particle stream may be doped or undoped. The temperature of the substrate might be sufficient to keep the surface of the so formed body at the same temperature. The silica body so formed is hot enough to allow for formation of a solid fused silica body. Densities between 80% and 100% may be expected as a result. [0068] The substrate may be tubular or solid form having the desired diameter and cross section. Desired ratios between the outside and inside diameters may be obtained using this method. If tubular, the substrate may be solid or porous, depending on the dopant or reactive gas flow desired. This achieves optimized silica material-to-gas contact. The hot substrate may also serve as a heater for the dopant gas and increased reaction time. Porous substrates can also diminish the possibility of gas bubbles entrapment near the surface of the substrate. [0069] Substrate and surface temperatures between about 700° C. and 1600° C. may result in various silica densities from 10% to 100%. Controlling the fused silica body temperature by controlling the substrate and surface temperature may result in control of the pore size and pore density in the material. If the variation is in the radial direction, exposure to dopant gas over periods of time will result in radial gradient of the dopant distribution. By doing so silica members having radially graded indexes of refraction may be fabricated. [0070] If the substrate is other than a silica core, doped or undoped made from fused silica or natural quartz; the resulting silica member may be in tubular form or may be in solid form after collapsing the tube. [0071] Employing non uniform substrate heating along the length of the body, one may obtain a silica member having variable density over its length. Example No. 2 Doped and Undoped Layer Combination Silica Body Fabrication [0072] Step 1. [0073] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle stream introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited, and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0074] Step 2. [0075] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for about 0.3 to 6 hours at temperature of about 800-1400° C., the silica material is doped. [0076] Step 3. [0077] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. A vitrified tubular silica body having desired wall thickness is formed. [0078] Step 4. [0079] The so formed vitrified tubular silica body is heated to temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0080] Step 5. [0081] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. The newly deposited porous silica is vitrified, and a tubular silica body having desired doped inner wall thickness IW t and undoped other wall OW t desired wall thickness is formed. The duration of the silica deposition for certain substrate cross sections and sizes can be adjusted to allow for various ratios between the wall thicknesses of the doped and undoped portion of the tubular member, e.g., 1:2, 1:3, 1:5, etc. Example No. 3 Doped Non-Porous and Undoped Porous Layer Combination Silica Body Fabrication [0082] Step 1. [0083] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle stream introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited, and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0084] Step 2. [0085] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for about 0.3-6 hours at temperature of about 800-1400° C., the silica material is doped. [0086] Step 3. [0087] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. A vitrified tubular silica body having desired wall thickness is formed. [0088] Step 4. [0089] The so formed vitrified tubular silica body is heated to temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. The duration of the silica deposition for certain substrate cross sections and sizes can be adjusted to allow for various ratios between the wall thicknesses of the doped and undoped portion of the tubular member, e.g., 1:2, 1:3, 1:5, etc. Example No. 4 Undoped Core and Fluorine Doped Cladding Fiber Optic Preform Fabrication [0090] Step 1. [0091] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle stream introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0092] Step 2. [0093] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0094] Step 3. [0095] The so formed vitrified tubular silica body is heated to temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0096] Step 4. [0097] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for about 0.3-6 hours at temperature of about 800-1400° C., the silica material is doped. [0098] Step 5. [0099] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. The newly deposited porous silica is vitrified, and a tubular silica body having desired doped inner wall thickness IW t and undoped outer wall OW t desired wall thickness is formed. [0100] Step 6. [0101] The substrate is transferred out of the deposition chamber area, and the substrate is removed. If wetting between the substrate and silica occurs, the substrate is heated to the softening point of the silica. The contact between the substrate and the silica member is melted and the substrate is removed. [0102] Step 7. [0103] The so formed silica member is collapsed and a solid rod like silica member is formed. Undoped core (high index of refraction material) surrounded by fluorine doped cladding (low index of refraction material) having desired diameter and length is formed. The duration of the silica deposition for certain substrate cross sections and sizes can be adjusted to allow for various ratios between the core diameter and the outside cladding layer diameter of the fiber optic preform, e.g., 1:2, 1:3, 1:5, etc. The length of the chamber and the translation capabilities can provide basis for fabrication fiber optic preforms that are up 6 inches or more in diameter and several meters in length. Example No. 5 Doped Core and Fluorine Doped Cladding Fiber Optic Preform fabrication [0104] Step 1. [0105] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica and dopant particle stream introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0106] Step 2. [0107] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0108] Step 1. [0109] The so formed vitrified tubular silica body is heated to temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0110] Step 4. [0111] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for about 0.3-6 hours at temperature of about 800-1400° C., the silica material is doped. [0112] Step 5. [0113] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. The newly deposited porous silica is vitrified, and a tubular silica body having desired doped inner wall thickness IW t and undoped outer wall OW t desired wall thickness is formed. [0114] Step 6. [0115] The substrate is transferred out of the deposition chamber area and the substrate is removed. If wetting between the substrate and silica occurs, the substrate is heated to the softening point of the silica. The contact between the substrate and the silica member is melted, and the substrate is removed. [0116] Step 7. [0117] The so formed silica member is collapsed and a solid rod like silica member is formed. Undoped core (high index of refraction material) surrounded by fluorine doped cladding (low index of refraction material) having desired diameter and length is formed. The duration of the silica deposition for certain substrate cross section and size can be adjusted to allow for various ratios between the core diameter and the outside cladding layer diameter of the fiber optic preform, e.g., 1:2, 1:3, 1:5, etc. The length of the chamber and the translation capabilities can provide basis for fabrication fiber optic preforms that are up 6 inches or more in diameter and several meters in length. Example No. 6 Doped Core and Fluorine Doped Graded Index of Refraction Cladding Fiber Optic Preform Fabrication [0118] Step 1. [0119] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica and dopant particle stream introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0120] Step 2. [0121] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0122] Step 3. [0123] The so formed vitrified tubular silica body is heated to temperature of about 1300° C. and is subjected to plurality of silica particle stream introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0124] Step 4. [0125] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for T 1 hours at temperature of 800-1400° C., the silica material is doped. T□ is about 0.3 to 2 hours. [0126] Step 5. [0127] The substrate and/or chamber temperature is raised to about 1400-1500° C. while rotating the substrate. The newly deposited porous silica is vitrified, and a tubular silica body having desired doped inner wall thickness IW t and undoped outer wall OW t desired wall thickness is formed. [0128] Step 6. [0129] The so formed vitrified tubular silica body is heated to temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The o accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0130] Step 7. [0131] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for T 2 >T 1 hours at a temperature of about 1100° C.-1400° C., the silica material is doped. T 2 is about 0.4-4 hours. [0132] Step 8. [0133] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. The newly deposited porous silica is vitrified, and a tubular silica body having desired doped inner wall thickness IW t and undoped outer wall OW t desired wall thickness is formed. [0134] Step 9. [0135] The so formed vitrified tubular silica body is heated to temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0136] Step 10. [0137] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for T 3 >T 2 hours at temperature of about 1100° C.-1400° C., the silica material is doped. T 3 is about 0.5-5 hours. [0138] Step 11. [0139] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. The newly deposited porous silica is vitrified, and a tubular silica body having desired doped inner wall thickness IW t and undoped outer wall OW t desired wall thickness is formed. [0140] Step 12. [0141] The so formed vitrified tubular silica body is heated to temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0142] Step 13. [0143] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for T 4 >T 3 hours at temperature of about 1100° C.-1400° C., the silica material is doped. T 4 is about 0.6 to 6 hours [0144] Step 14. [0145] The substrate and/or chamber temperature is raised to 1400-1600° C. while rotating the substrate. The newly deposited porous silica is vitrified and a tubular silica body having desired doped inner wall thickness IW t and undoped outer wall OW t desired wall thickness is formed. [0146] Steps 15-17. [0147] Repeat Steps 12-14 while further reducing the exposure to gaseous dopant, SiF4 in this case. [0148] Step 18. [0149] The substrate is transferred out of the deposition chamber area and the substrate is removed. If wetting between the substrate and silica occurs, the substrate is heated to the softening point of the silica. The contact between the substrate and the silica member is melted and the substrate is removed. [0150] Step 19. [0151] The so formed silica member is collapsed and a solid rod like silica member is formed. Undoped core (high index of refraction material) surrounded by graded index of refraction fluorine doped cladding (low index of refraction material) having desired diameter and length is formed. The duration of the silica deposition for certain substrate cross section and size can be adjusted to allow for various ratios between the core diameter and the outside cladding layer diameter of the fiber optic preform, e.g., 1:2, 1:3, 1:5, etc. The length of the chamber and the translation capabilities can provide basis for fabrication fiber optic preforms that are up 6 inches or more in diameter and several meters in length. Example No. 7 Doped Core Having Graded Index of Refraction and Fluorine Doped Graded Index of Refraction Cladding Fiber Optic Preform Fabrication [0152] Step 1. [0153] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica and dopant particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0154] Step 2. [0155] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0156] Step 3. [0157] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle streams and reduced dopant particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0158] Step 4. [0159] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0160] Step 5. [0161] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle streams and further reduced dopant particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. Porous silica body having about 25-35% solid glass density is obtained by this process. [0162] Step 6. [0163] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0164] Step 7-9 [0165] Repeat steps 4-6 further reducing the dopant levels in the deposited silica by lowering the dopant concentrations in the dopant particle streams, etc. [0166] Step 10. [0167] The so formed vitrified tubular silica body is heated to temperature of 1300° C. and is subjected to plurality of silica particle stream introduced via ports on the chamber. The so accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. Porous silica body having 25-35% solid glass density is obtained by this process. [0168] Step 11. [0169] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for T 1 hours at temperature of about 1100° c.-1400° C. the silica material is doped. T 1 is about 0.3 to 2 hours. [0170] Step 12. [0171] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. The newly deposited porous silica is vitrified, and a tubular silica body having desired doped inner wall thickness IW t and undoped outer wall OW t desired wall thickness is formed. [0172] Step 13. [0173] The so formed vitrified tubular silica body is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. Porous silica body having about 25-35% solid glass density is obtained by this process. [0174] Step 14. [0175] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for T 2 >T 1 hours at temperature of about 1100° C.-1400° C. the silica material is doped. T 2 is about 0.4 to 4 hours. [0176] Step 15. [0177] The substrate and/or chamber temperature is raised to about 1400-1500° C. while rotating the substrate. The newly deposited porous silica is vitrified, and a tubular silica body having desired doped inner wall thickness IW t and undoped outer wall OW t desired wall thickness is formed. [0178] Step 16. [0179] The so formed vitrified tubular silica body is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0180] Step 17. [0181] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for T 3 >T 2 hours at temperature of about 1100° C.-1400° C. the silica material is doped. T 3 is about 0.6 to 6 hours. [0182] Step 18. [0183] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. The newly deposited porous silica is vitrified, and a tubular silica body having desired doped inner wall thickness IW t and undoped outer wall OW t desired wall thickness is formed. [0184] Step 19. [0185] The so formed vitrified tubular silica body is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having 25-35% solid glass density is obtained by this process. [0186] Step 20. [0187] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and/or the chamber into the deposited porous silica material for T 4 >T 3 hours at temperature of 1100° C.-1400° C., the silica material is doped. T 4 is about 0.6 to 6 hours [0188] Step 21. [0189] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. The newly deposited porous silica is vitrified and a tubular silica body having desired doped inner wall thickness IW t and undoped outer wall OW t desired wall thickness is formed. [0190] Step 22-24. [0191] Repeat Steps 12-14 while further reducing the exposure to gaseous dopant, SiF4 in this case. [0192] Step 25. [0193] The substrate is transferred out of the deposition chamber area and the substrate is removed. If wetting between the substrate and silica occurs, the substrate is heated to the softening point of the silica. The contact between the substrate and the silica member is melted and the substrate is removed. [0194] Step 26. [0195] The so formed silica member is collapsed and a solid rod like silica member is formed. Undoped core (high index of refraction material) surrounded by graded index of refraction fluorine doped cladding (low index of refraction material) having desired diameter and length is formed. The duration of the silica deposition for certain substrate cross sections and sizes can be adjusted to allow for various ratios between the core diameter and the outside cladding layer diameter of the fiber optic preform, e.g., 1:2, 1:3, 1:5, etc. The length of the chamber and the translation capabilities can provide basis for fabrication fiber optic preforms that are up 6 inches or more in diameter and several meters in length. The radial distribution of the index of refraction in the core and the cladding will depend on the thickness of the doped layer deposited and on the pore density in the as deposited preform. Example No. 8 Doped Core Having Graded Index of Refraction and Fluorine Doped Cladding Having Graded Index of Refraction Fiber Optic Preform Fabrication [0196] Step 1. [0197] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica and dopant particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0198] Step 2. [0199] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0200] Step 3. [0201] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle stream and reduced concentration dopant particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% fused silica density is obtained by this process. [0202] Step 4. [0203] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0204] Step 5. [0205] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle streams and further reduced concentration dopant particle stream introduced via ports on the chamber. The so accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% fused silica density is obtained by this process. [0206] Step 6. [0207] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0208] Step 7-9. [0209] Repeat steps 4-6 further reducing the dopant levels in the deposited silica by further lowering the dopant concentrations in the dopant particle stream. Repeat until the desired index of refraction profile in radial direction is obtained. [0210] Step 10. [0211] The so formed vitrified tubular silica body is heated to a temperature of about 1380° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 80-90% fused silica density is obtained by this process. [0212] Step 11. [0213] The so formed silica body is heated to a temperature of about 1370° C. and is subjected to plurality of silica particle stream introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 75-85% solid glass density is obtained by this process. [0214] Step 12. [0215] The so formed vitrified tubular silica body is heated to temperature of 1360° C. and is subjected to plurality of silica particle stream introduced via ports on the chamber. The so accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 65-75% fused silica density is obtained by this process. [0216] Step 13. [0217] The so formed vitrified tubular silica body is heated to a temperature of about 1330° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 50-60% fused silica density is obtained by this process. [0218] Step 14. [0219] The so formed vitrified tubular silica body is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% fused silica density is obtained by this process. [0220] Step 15. [0221] Introducing silicon tetra fluoride, SiF 4 , through the chamber into the deposited porous silica material for about 0.3-6 hours at temperature of 1100° C.-1400° C. the silica material is doped. The amount of the SiF 4 penetrating the cladding will be proportional to the pore density and the exposure time at given temperature of the preform. [0222] Step 16. [0223] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. The newly deposited porous silica is vitrified, and a tubular silica body having desired cladding layer wall thickness is formed. Repeat until the desired index of refraction profile in radial direction is obtained. [0224] Step 17. [0225] The substrate is transferred out of the deposition chamber area and the substrate is removed. If wetting between the substrate and silica occurs, the substrate is heated to the softening point of the silica. The contact between the substrate and the silica member is melted and the substrate is removed. [0226] Step 18. [0227] The so formed silica member is collapsed and a solid rod like silica member is formed. Undoped core (high index of refraction material) surrounded by graded index of refraction fluorine doped cladding (low index of refraction material) having desired diameter and length is formed. The duration of the silica deposition for certain substrate cross sections and sizes can be adjusted to allow for various ratios between the core diameter and the outside cladding layer diameter of the fiber optic preform, e.g., 1:2, 1:3, 1:5, etc. The length of the chamber and the translation capabilities can provide basis for fabrication fiber optic preforms that are up 6 inches or more in diameter and several meters in length. The radial distribution of the index of refraction in the core and the cladding will depend on the thickness of the doped layer deposited and on the pore density in the deposited preform. Example No. 9 Fluorine Doped Cladding Having Graded Index of Refraction Fiber Optic Preform Fabrication Using Prefabricated Doped or Undoped Core Rod [0228] Step 1. [0229] Prefabricated silica doped or undoped rod is heated to a temperature of about 1400° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The so accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 90-100% fused silica density is obtained by this process. [0230] Step 2. [0231] Prefabricated silica doped or undoped rod is heated to a temperature of about 1380° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 80-90% fused silica density is obtained by this process. [0232] Step 3. [0233] The so formed silica body is heated to a temperature of about 1370° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 75-85% solid glass density is obtained by this process. [0234] Step 4. [0235] The so formed vitrified tubular silica body is heated to a temperature of about 1360° C. and is subjected to plurality of silica particle stream introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 65-75% fused silica density is obtained by this process. [0236] Step 5. [0237] The so formed vitrified tubular silica body is heated to a temperature of about 1330° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 50-60% fused silica density is obtained by this process. [0238] Step 6. [0239] The so formed vitrified tubular silica body is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% fused silica density is obtained by this process. [0240] Step 7. [0241] Introducing silicon tetra fluoride, SiF 4 , through the chamber into the deposited porous silica material for about 0.3-6 hours at temperature of about 1100° -1400° C. the silica material is doped. The amount of the SiF 4 penetrating the cladding will be proportional to the pore density and the exposure time at given temperature of the preform. [0242] Step 8. [0243] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. The newly deposited porous silica is vitrified, and a tubular silica body having desired cladding layer wall thickness is formed. Repeat until the desired index of refraction profile in radial direction is obtained. [0244] Step 26. [0245] The so formed silica member is vitrified and a solid rod like silica member is formed. Doped or undoped core (high index of refraction material) surrounded by graded index of refraction fluorine doped cladding (low index of refraction material) having desired diameter and length is formed. The duration of the silica deposition for certain substrate cross sections and sizes can be adjusted to allow for various ratios between the core diameter and the outside cladding layer diameter of the fiber optic preform, e.g., 1:2, 1:3, 1:5, etc. The length of the chamber and the translation capabilities can provide basis for fabrication fiber optic preforms that are up 6 inches or more in diameter and several meters in length. The radial distribution of the index of refraction in the core and the cladding will depend on the thickness of the doped layer deposited and on the pore density in the as deposited preform. Example No. 10 Process For Fabrication of Fluorine Doped Cladding Tube Having Graded Index of Refraction Fiber Optic Preform Fabrication [0246] Step 1. [0247] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1400° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 90-100% fused silica density is obtained by this process. [0248] Step 2. [0249] Prefabricated silica doped or undoped rod is heated to a temperature of about 1380° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 80-90% fused silica density is obtained by this process. [0250] Step 3. [0251] The so formed silica body is heated to a temperature of about 1370° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The so accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 75-85% solid glass density is obtained by this process. [0252] Step 4. [0253] The so formed vitrified tubular silica body is heated to a temperature of about 1360° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 65-75% fused silica density is obtained by this process. [0254] Step 5. [0255] The so formed vitrified tubular silica body is heated to a temperature of about 1330° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 50-60% fused silica density is obtained by this process. [0256] Step 6. [0257] The so formed vitrified tubular silica body is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% fused silica density is obtained by this process. [0258] Step 7. [0259] Introducing silicon tetra fluoride, SiF 4 , through the porous substrate and the chamber into the deposited porous silica material for about 0.3-6 hours at temperature of about 1100° C.-1400° C., the silica material is doped. The amount of the SiF 4 penetrating the cladding will be proportional to the pore density and the exposure time at given temperature of the preform. [0260] Step 7. [0261] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate. The porous silica is vitrified and a tubular silica body having desired cladding layer wall thickness is formed. [0262] Step 9. [0263] The substrate is transferred out of the deposition chamber area and the substrate is removed. If wetting between the substrate and silica occurs, the substrate is heated to the softening point of the silica. The contact between the substrate and the silica member is melted and the substrate is removed. The duration of the silica deposition for certain substrate cross sections and sizes can be adjusted to allow for various ratios between the inner diameter and the outside diameter of the tubing fiber optic preform, e.g., 1:2, 1:3, 1:5, etc. The length of the chamber and the translation capabilities can provide basis for fabrication doped tubing for fiber optic preforms that are up 12 inches or more in diameter and several meters in length. The radial distribution of the index of refraction in the cladding will depend on the thickness of the doped layer deposited and or the pore density in the as deposited preform. Example No. 11 Doped Core Having Graded Index of Refraction For Fiber Optic Preform Fabrication [0264] Step 1. [0265] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica and dopant particle streams introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% solid glass density is obtained by this process. [0266] Step 2. [0267] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0268] Step 3. [0269] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle streams and reduced concentration dopant particle stream introduced via ports on the chamber. The so accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% fused silica density is obtained by this process. [0270] Step 4. [0271] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0272] Step 5. [0273] Rotating and translating, a substrate consisting of porous tubing is heated to a temperature of about 1300° C. and is subjected to plurality of silica particle streams and further reduced concentration dopant particle stream introduced via ports on the chamber. The accelerated particles collide with the substrate and deposit themselves on the substrate. Subsequent particles deposit on the material already deposited and layer by layer the silica member is formed. A porous silica body having about 25-35% fused silica density is obtained by this process. [0274] Step 6. [0275] The substrate and/or chamber temperature is raised to about 1400-1600° C. while rotating the substrate and maintained there for certain time interval. A vitrified tubular silica body having desired wall thickness is formed. [0276] Step 7-9. [0277] Repeat steps 4-6 further reducing the dopant levels in the deposited silica by further lowering the dopant concentrations in the dopant particle stream. Repeat until the desired index of refraction profile in radial direction is obtained. [0278] Step 10. [0279] The substrate is transferred out of the deposition chamber area and the substrate is removed. If wetting between the substrate and silica occurs, the substrate is heated to the softening point of the silica. The contact between the substrate and the silica member is melted and the substrate is removed. [0280] Step 11. [0281] The so formed silica member is collapsed and a solid rod like silica member is formed. Graded index of refraction core having desired diameter and length is formed. The duration of the silica deposition for certain substrate cross sections and sizes can be adjusted to allow for various ratios between the inner diameter and the outside diameter of the tubing fiber optic preform, e.g., 1:2, 1:3, 1:5, etc. The length of the chamber and the translation capabilities can provide basis for fabrication doped cores for fiber optic preforms that are up 12 inches or more in diameter and several meters in length. The radial distribution of the index of refraction in the cladding will depend on the thickness of the doped layer deposited and on the pore density in the deposited preform. [0282] While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention, which is defined in the following claims.

Silica grain of desired properties and size is created in a vacuum chamber. Fine silica powder is injected in the chamber or silica powder is formed in situ by combusting precursors. A plasma is formed centrally in the chamber to soften the silica powders so that they stick together and form larger grains of desired size. The grains are collected, doped, fused and flowed into tubes or rods. A puller pulls the tube or rod through a chamber seal into a lower connected vacuum chamber. The tube or rod is converted to rods and fibers or plates and bars in the connected chamber. Fused silica in a crucible tray is subjected to ultrasound or other oscillations for outgassing. Gases are removed by closely positioned vacuum ports.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ion implantation, and more especially, to −low temperature ion implantation. 2. Background of the Related Art Low temperature ion implantation is a new application of ion implantation. It has been discovered that a relatively low wafer temperature during ion implantation is advantageous for the formation of shallow junctions, especially ultra-shallow junctions, which are more and more important for continued miniaturization of semiconductor devices. Besides, it also has been proven to be useful for enhancing the yield of the ion implantation. At the start of the current low temperature ion implantation, a wafer is moved from an environment, such as an atmosphere environment, into an implanter. As shown in FIG. 1 a , before the implant process is started, a cooling process (from t c to t i ) cools the wafer temperature from an environment temperature (T R ) of about 15˜25° C. to a prescribed implant temperature (T P ) (or to be essentially equal to the prescribed implant temperature), which usually is lower than the freezing point of water and generally is about −15˜−25° C. As usual, the prescribed implant temperature represents the setting temperature of an E-chuck, which is used to hold the wafer. Herein, the wafer can be cooled at least in a cassette outside the implanter, in a loadlock chamber of the implanter, in a chamber of the implanter, and so on. In general, as shown in FIG. 1 b , a backside gas with a constant pressure (P 0 ) is applied to cool the wafer and it requires several seconds (even minutes) to cool down the wafer from the environment temperature (T R ) to the prescribed implant temperature (T P ). After that, the backside gas with the constant pressure is still applied to cool the wafer during the implant process. Referring still to FIG. 1 a , during the implant process (from t i to t h ) of the wafer, the wafer is heated by the ion beam energy and cooled by a cooling mechanism, such as a backside cooling gas. Usually, to keep the wafer to have appropriate implant quality in the low temperature ion implantation, the pressure of the backside gas is properly adjusted to ensure the wafer temperature is always equal to the prescribed implant temperature (T P ) or at least is not higher an upper-limited temperature (T L ) during the implant process. Herein, the rise curve of the wafer temperature during the implant process (from t i to t h ) may be linear or non-linear, and the rise curve shown in FIG. 1 a is only a sketch. On the other hand, if the upper-limited temperature (T L ) is close to the prescribed implant temperature (T P ), as shown in FIG. 1 a ′, the wafer temperature during the implant process (from t i to t h ) may be thought of as constant. After finishing the implant process, referring still to FIG. 1 a or FIG. 1 a ′, a heating process (from t h to t f ) proceeds to heat the implanted wafer until the wafer has an environment temperature (T R ′). Herein the environment temperature (T R ′) may correspond to the atmosphere environment temperature, so that the difference between the implanted wafer temperature, which will be moved out of the ion implanter immediately, and the environment temperature is decreased. Hence, owing to the decreased temperature difference, the water condensation problem on the wafer surface induced by the temperature difference may be avoided or minimized. In general, after the implant process, the implanted wafer is transferred into a loadlock chamber in a vacuum state to proceed with the heating process. As usual, to avoid any potential contamination, the implanted wafer is not heated by an active heat source but is heated by thermal radiation between the wafer and the load-lock chamber walls. After the temperature of the implanted wafer reaches the environment temperature (T R '), the load-lock chamber is vented and the implanted wafer is moved outside the loadlock chamber immediately. Herein, owing to the low efficiency of the radiation heat transfer mechanism, it requires some seconds (even some minutes) to heat up the implanted wafer from the prescribed implant temperature (T P ) to the environment temperature (T R ′). Therefore, both the cooling process and heating process are time-consuming, so that the wafer throughput of the low temperature ion implantation is limited. SUMMARY OF THE INVENTION In order to solve the foregoing problems, this invention provides a method for low temperature ion implantation with improved wafer throughput. A feature of the invention is that the operation of the cooling mechanism is stronger in the cooling process and weaker in the implant process. Hence, the cooling rate can be enhanced and then the required period of the cooling process can be shortened. Accordingly, a low temperature ion implant may proceed in accordance with the following steps in sequence. Firstly, a cooling process proceeds to cool a wafer, wherein a temperature adjustment device is operated in a first state so that a temperature of the wafer is changed from a first temperature to a second temperature. Then, implant the wafer in an implantation chamber, wherein a temperature adjustment device is operated in a second state so that a temperature of the wafer is essentially between the second temperature and a third temperature higher than the second temperature. Next, transfer the implanted wafer into a load lock chamber. Finally, vent vacuum in the loadlock chamber and then move the wafer outside the loadlock chamber. Herein, as an example, the temperature adjustment device applies a gas to cool the wafer, the first state corresponds to a first pressure of the gas and the second state corresponds to a second pressure of the gas, wherein the first pressure is higher than the second pressure. Another feature of the invention is that the wafer is not immediately moved out the ion implanter after a vacuum venting process is finished. Hence, the wafer temperature may be increased quickly inside the ion implanter before the wafer is moved into the outside environment. Accordingly, a low temperature ion implant may proceed in accordance with the following steps in sequence. Firstly, a cooling process proceeds to cool a wafer from a first temperature to a second temperature. Next, implant the wafer in an implantation chamber as a temperature of the wafer is essentially between the second temperature and a third temperature higher than the second temperature; then, transfer the implanted wafer into a load-lock chamber in a vacuum state, wherein the load-lock chamber has at least an atmosphere door as an interface between the load-lock chamber and an outside environment, wherein the atmosphere door is closed when the load-lock chamber in the vacuum state. And then, proceed with a vacuum venting process in the load-lock chamber and wait an extra time after the vacuum venting process until the wafer has a third temperature. Finally, open the atmosphere door and move the wafer outside the load-lock chamber. Still another feature of the invention is that a temperature measurement device is used to monitor the wafer temperature. Hence, to change the operation of the cooling mechanism and to open the atmosphere door can be more precisely controlled. Of course, to minimize potential contamination, a non-contact type temperature measuring device may be used. Significantly, the invention never limits the practical details about the operation of the cooling apparatus in the cooling process and the operation of the cooling apparatus in the implant process. The only limitation is that the operation of the cooling apparatus is higher (stronger) in the cooling process but is lower (weaker) in the implantation process. Similarly, the invention never limits the practical period of the extra waiting time. The only limitation is that the wafer is not moved out the ion implanter immediately after the vacuum venting process. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 a and FIG. 1 a ′ are two diagrams illustrating conventional relations between the wafer temperature and the time during the low temperature ion implantation step; FIG. 1 b is a diagram illustrating a conventional relation between the gas pressure and the time during the cooling process and the implant process; FIG. 2 a and FIG. 2 b are two diagrams respectively illustrating relations between the gas pressure and the time during the cooling process and the implant process in accordance with two embodiments of the present invention; FIG. 2 c is a diagram illustrating relation between the wafer temperature and the time in accordance with an embodiment of the present invention; FIG. 3 is a diagram illustrating different forces applied to a wafer in accordance with an embodiment of the present invention; and FIG. 4 is a diagram illustrating a relation between the wafer temperature and the time during the low temperature ion implantation step in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The detailed description of the present invention will be discussed in the following embodiments, which are not intended to limit the scope of the present invention, but can be adapted for other applications. While drawings are illustrated in details, it is appreciated that the quantity of the disclosed components may be greater or less than that disclosed, except expressly restricting the amount of the components. In one embodiment, the temperature adjustment device applies a gas to cool the wafer, wherein the gas is a backside gas to take heat away the wafer from the backside of the wafer. As shown on FIG. 2 a , a first state from time of t c to t i is that the temperature adjustment device applies a gas with a first pressure (P 1 ), and a second state from time of t i to t h is that the temperature adjustment device applies a gas with a second pressure (P 2 ). Herein, the first pressure is higher than the second pressure and the first pressure is a constant. Further, the first pressure may be variable with time, or as shown in FIG. 2 b , the first pressure is temporarily increased to be higher than the second pressure. In other non-illustrated embodiment, the first pressure may be temporarily varied, continually varied or continuously varied during the cooling process, when the first pressure is higher than the second pressure. As shown in FIG. 2 c , in the above embodiments, the required time of the cooling process is reduced because the higher gas pressure during the cooling process may more efficiently take the heat away. Herein, the upper-limited temperature (T L ) is assumed to be slightly higher than the prescribed implant temperature (T P ) and the wafer temperature variation is assumed to be linear, although they are independent on the main characteristics of this embodiment. Clearly, the higher the gas pressure is, the faster the wafer temperature is reduced. Hence, the essential mechanism of these embodiments is that the gas pressure is higher during the cooling process but is lower during the implant process. In other words, how the gas pressure is varied during the cooling pressure is not limited. For example, when the average gas pressure during the cooling process is higher than the fixed gas pressure in the implant process, it is optional that the gas pressure is lower than the fixed gas pressure during some portions of the cooling process. To compare with the conventional prior art, the main difference between the above embodiment(s) and the conventional prior art is the gas pressure in the cooling process. Reasonably, the above embodiment(s) use higher gas pressure in the cooling process, and then the decreased rate of the wafer temperature is higher in the cooling process. Therefore, by comparing FIG. 2 c with FIG. 1 a , the above embodiments can effectively shorten the required period of the cooling process to reduce the wafer temperature from environment temperature to the required implant temperature. It is noted that the higher gas pressure will cause a higher pushing force (F p ), which attempts to push the wafer 12 away, as shown in FIG. 3 . In general, the wafer 12 is held by using an E-chuck 14 , which provides an electrostatic force (F e ) to the wafer. The electrostatic force (F e ) is an attracting force to cause the wafer 12 to be held on the E-chuck 14 stably. Hence, to avoid the unacceptable damage or displacement of the wafer 12 , the gas pressure has to be balanced with the electrostatic force. In other words, the pushing force (F p ) from the gas pressure has to be equal to or less than the attracting force. Further, when the higher gas pressure is needed to speed up the cooling process, the electrostatic force (F e ) should be correspondingly increased to prevent unacceptable movement or damage of the wafer 12 . Of course, depending on the design of the ion implanter, sometimes the gravity force on the wafer also is a portion of the repulsing force or the attracting force. However, the gravity force is a constant and may be viewed as a background only. Further, although back side gas cooling is the commonly used cooling mechanism, the invention is not limited by the practical details of the cooling mechanism. In another embodiment, the temperature adjustment device is a temperature controlled chuck capable of holding the wafer. Hence, the temperature adjustment device operated in the first state means that the temperature controlled chuck is adjusted to have a lower working temperature, and the temperature adjustment device operated in the second state means that the temperature controlled chuck is adjusted to have a higher working temperature. According to the different working temperature of a temperature controlled chuck, a wafer held by the temperature controlled chuck will have a different wafer temperature, especially a different changing rate of wafer temperature, during the cooling process and the implant process. In general, the low temperature ion implantation process is divided into at least an implant process, a cooling process to cool down the wafer before the implant process and a heating process to heat up the wafer after the implant process. In the present invention, because the period of the cooling process is shortened, the throughput of the low temperature ion implantation step is improved. Moreover, as an example, to precisely adjust the pressure of the backside gas as the wafer is cooled to the required temperature for properly implanting the wafer, a temperature measurement device is optionally configured near the wafer to detect the wafer temperature so let the wafer temperature may be dynamically monitored in a real-time manner. The temperature measurement device may be a thermocouple, an infrared thermometer, a non-contact type temperature measurement device or any combination thereof. Moreover, to avoid any potential contamination, such as particle contamination from the interaction between the temperature measurement device and the ion beam, a non-contact type temperature measurement device is an option. On the other hand, another embodiment is a method for low temperature ion implantation, please refer to FIG. 4 . Firstly, a cooling process proceeds to cool a wafer from a first temperature to a second temperature, wherein the first temperature is room temperature (T R ). Then, implant the wafer in an implantation chamber as the wafer temperature is essentially between the second temperature and a third temperature, wherein the third temperature is higher than the second temperature and is an upper-limited temperature (T L ) which is allowable for the low temperature ion implantation step. Depending on the additional details of the implant process, the upper-limited temperature may be equal to, close to or visibly different than the second temperature. And then, transfer the implanted wafer into a load-lock chamber in a vacuum state at time of t h , wherein the load-lock chamber has at least one atmosphere door as an interface between the load-lock chamber and outside environment, wherein the atmosphere door is closed when the load-lock chamber is in the vacuum state. Next, execute a vacuum venting process in the load-lock chamber, wherein the vacuum venting process proceeds at a time t v . Sequentially, wait an extra time after the vacuum venting process until the wafer has a fourth temperature at time t f , wherein the fourth temperature (T 4 ) is higher than the prescribed implant temperature (T P ) and the upper-limited temperature (T L ). And finally, open the atmosphere door and move the wafer outside the load-lock chamber. Herein, the upper-limited temperature (T L ) is assumed to be slightly higher than the prescribed implant temperature (T P ) and the wafer temperature variation is assumed to be linear, although that is immaterial to the main characteristics of this embodiment. In this embodiment, the wafer contacts the air from the outside environment after the atmosphere door is opened. Clearly, the wafer has the fourth temperature being higher than the prescribed implant temperature (T P ) and the upper-limited temperature (T L ) before the atmosphere door is opened, and then the water condensation on the surface of the wafer may be minimized. Moreover, during the vacuum venting process, a gas admitted into the load-lock chamber is a warm dry gas or heated nitrogen gas. Hence, after the vacuum venting process and before the opening of the atmosphere door, the wafer in the load lock chamber is surrounded by this gas so that the wafer temperature may be quickly raised. Note that the energy interchange mechanism between the gas surrounding the wafer and the wafer itself is significantly more efficient than the radiation mechanism between the vacuum environment surrounding the wafer and the wafer itself. Therefore, to induce same temperature increase, the required extra time by using the embodiment is significantly shorter than the required time by using the prior art that the wafer is heated by a radiation mechanism between the wafer and a vacuum environment in the load-lock chamber. Accordingly, the throughput of low temperature ion implantation may be further improved by the embodiments. Moreover, as described in the above embodiments, to properly control the extra time, even the fourth temperature, a temperature measurement device is configured near the wafer to detect the wafer temperature, so that the temperature adjusting process may be stopped immediately when the required third temperature is arrived. The temperature measurement device may be chosen from a thermocouple, an infrared thermometer or a non-contact type temperature measurement device for minimizing any potential condensation. Although the present invention has been explained in relation to its preferred embodiment, it is to be understood that other modifications and variations can be made without departing from the spirit and scope of the invention as hereafter claimed.

Techniques for low temperature ion implantation are provided to improve throughput. Specifically, the pressure of the backside gas may temporarily, continually or continuously increase before the starting of the implant process, such that the wafer may be quickly cooled down from room temperature to be essentially equal to the prescribed implant temperature. Further, after the vacuum venting process, the wafer may wait an extra time in the load lock chamber before the wafer is moved out the ion implanter, in order to allow the wafer temperature to reach a higher temperature quickly for minimizing water condensation on the wafer surface. Furthermore, to accurately monitor the wafer temperature during a period of changing wafer temperature, a non-contact type temperature measuring device may be used to monitor wafer temperature in a real time manner with minimized condensation.

This is a continuation of application Serial No. 840,785, filed March 18, 1986 now U.S. Pat. 4,782,526. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone set of the type including a telephone body and a handset adapted to be placed in position on the former and more particularly to improvement of or relation to a telephone of the abovementioned type which assures that the handset is firmly held on the telephone body in order that it is not easy to fall down from the latter. 2. Description of the Prior Art To facilitate understanding of the present invention it will be helpful that a typical conventional telephone of the above-mentioned type will be briefly described with reference to FIG. 1 which is a schematic side view of a telephone adapted to be mounted on a motorcar (hereinafter referred to simply as telephone). The telephone has a pawl B and a pawl C incorporated in a telephone body A and both the pawl B and C are biased in the opposite direction under the effect of resilient force of springs b and c. As is apparent from the drawing, the foremost ends of the pawls B and C are fitted into recesses E and F which are formed on the handset D whereby the latter is firmly held on the telephone body A. In order to inhibit the handset D held on the telephone body from rattling or falling down from the latter during running of a motorcar under the vibratory condition there is a necessity for allowing the pawls B and C to be thrusted against the recesses E and F on the handset D with a high intensity of resilient force. However, the fact that an intensity of thrusting force of the pawls B and C against the handset D, that is, an intensity of urging force of the pawls B and C is determined to a high level means that a high intensity of manual force is required when the handset D is placed in position on the telephone body A or when the handset D is removed or taken up from the telephone body A. As a result, the telephone is difficult or troublesome to operate. Since an arrangement is made such that the two pawls B and C are urged with a high intensity of resilient force, it is unavoidably necessary that both the springs b and c are designed in larger dimensions. This leads to a necessity for a wide hollow space in the interior of the telephone body A so as to allow the larger springs b and c to be accommodated therein. This means that the whole telephone become larger. SUMMARY OF THE INVENTION Thus, the present invention has been made with the foregoing background in mind and its object resides in providing an improved telephone of the early-mentioned type which assures that a handset properly held on a telephone body is reliably inhibited from falling down from the latter and the handset is placed on and taken up from the telephone body with a lower intensity of manual force. Another object of the present invention is to provide an improved telephone of the early mentioned type which is designed in smaller dimensions. To accomplish the above objects there is proposed according to the present invention a telephone of the type including a handset which is formed with a holding recess in the central area thereof, the holding recess having faces oppositely located to one another each of the faces being formed with an engagement recess, and a telephone body which is integrally formed with a projected portion having the trapezoidal configuration as seen from the side, the projected portion being adapted to be fitted into the holding recess of the handset, both the end faces of the projected portion including first and second engagement blocks adapted to be fitted into the engagement recesses of the handset, the first and second engagement blocks being biased in the opposite direction under the effect of resilient force of spring means, wherein the improvement consists in that at least the first engagement block is disposed so as to move in the direction at a substantially right angle relative to the direction of mounting and dismounting of the handset on and from the telephone body and moreover it is formed with an engagement face on the bottom thereof which extends in the direction of movement of the first engagement block and that the engagement recess is formed with an engagement portion adapted to come in contact with the engagement face of the engagement block, the position of the engagement portion being so determined that it is located in alignment with the engagement face of the first engagement block when the latter is fitted into the engagement recess on the handset. By virtue of the arrangement made in that way it is assured that the handset is reliably held on the telephone body. Since holding of the handset is achieved mainly by cooperation of the engagement face with the engagement portion, there is no necessity for a high intensity of urging force for actuating the first and second engagement blocks. Thus, small-sized urging means such as coil spring or the like can be used for the purpose of actuating the engagement blocks, resulting in the whole telephone being designed and constructed in smaller dimensions. Other objects, features and advantages of the present invention will become readily apparent from reading of the following description which has been prepared in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings will be briefly described below. FIG. 1 is a schematic side view of a conventional telephone of the type including a telephone body and a handset. FIG. 2 is a perspective view of a telephone of the above-mentioned type in accordance with the present invention, particularly showing an appearance of the whole structure of the telephone handset of which is held in position of the telephone body. FIG. 3 is a side view of the telephone in FIG. 2. FIG. 4 is a partially sectioned side view of the telephone in accordance with an embodiment of the invention, particularly illustrating how essential components constituting the telephone are arranged. FIG. 5 is a sectional plan view of the telephone taken in line V-V in FIG. 3. FIG. 6 is a fragmental vertical sectional view of the telephone, particularly illustrating how the handset is firmly held in position on the telephone body in the area including a cradle on the telephone sending side. FIG. 7 is a fragmental vertical sectional view of the telephone taken in line VII-VII in FIG. 3, particularly illustrating how an unlocking button is incorporated in the telephone body. FIG. 8 is a sectional plan view of a telephone in accordance with other embodiment of the present invention, wherein leaf springs are employed as actuating means for engagement blocks. FIG. 9 is a sectional plan view of a telephone in accordance with another embodiment of the present invention, wherein the one engagement block is actuated directly by means of an actuating member. FIG. 10 is a fragmental vertical sectional view of a telephone in accordance with further another embodiment of the present invention, wherein the handset is raised up by means of a button with a compression spring accommodated therein in the area including a cradle on the sending side. FIG. 11 is a fragmental vertical sectional view of a telephone in accordance with still further another embodiment of the present invention similar to FIG. 10, wherein the handset is raised up by means of a block made of elastomeric material in the area including a cradle on the sending side. FIG. 12 is a fragmental vertical sectional view of a telephone in accordance with a modified embodiment of the present invention similar to FIG. 10, wherein a pawl and an engagement recess are designed in a different manner on the sending side. FIG. 13 is a fragmental vertical sectional view of a telephone in accordance with other modified embodiment of the present invention, wherein a pawl and an engagement recess are designed in another different manner on the receiving side. FIG. 14 is a fragmental vertical sectional view of a telephone in accordance with another modified embodiment of the present invention similar to FIG. 13, wherein an engagement block is turnably disposed on the receiving side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Now, the present invention will be described in a greater detail hereunder with reference to the accompanying drawings which illustrate preferred embodiments thereof. First, referring to FIGS. 2 and 4, the telephone of the invention includes a telephone body 1 and a handset 2. The telephone body 1 is integrally formed with a projected portion 1a having the trapezoidal configuration as seen from the side on its upper central part and moreover it includes a telephone receiving side cradle 3 on the right-hand side and a telephone sending side cradle 4 on the left-hand side of the trapezoidal projected portion 1a (as seen in FIGS. 3 and 4). The cradle 4 is provided with a first engagement block 100 on the one end face 1c of the projected portion 1a so as to allow an engagement pawl 101 to be projected therefrom, whereas the cradle 3 is provided with a second engagement block 100' on the other end face 1b of the projected portion 1a so as to allow an engagement pawl 101' to be projected therefrom. On the other hand, the handset 2 includes a telephone receiving section 5, a telephone sending section 6 and a junction section 2a by way of which the receiving section 5 and the sending section 6 are jointed to one another whereby a holding recess 2b is formed by the combination of receiving section 5, sending section 6 and junction section 2a. Further, the handset 2 has oppositely located faces in the holding recess 2b, one of the oppositely located faces being an inside face 5a of the receiving section 5 and the other one being an inside face 6a of the sending section 6. The inside face 5a of the receiving section 5 is formed with an engagement recess 7, whereas the inside face 6a of the sending section 6 is formed with an engagement recess 8. As will be apparent from FIG. 4, the handset 2 is held on the body 1 by fitting the pawls 101 and 101' of the engagement blocks 100 and 100' into the engagement recesses 7 and 8. At this moment the central part of the trapezoidal projected portion 1a is received in the hollow space as defined by the holding recess 2b of the handset 2. The handset 2 has a rear face 2c located opposite to the holding recess 2b and a control portion 2e with a number of control buttons 2d arranged thereon disposed in the area located on the left-hand side as seen in FIG. 2 (on the right-hand side as seen in FIGS. 3 and 4) on the rear face 2c. Further, the handset 2 includes a grasping portion 2f in the area located on the right-hand side as seen in FIG. 2 so as to allow the handset 2 to be easily grasped by an operator. As shown in FIG. 4, a hook button 9 is accommodated in the sending side cradle 4 of the telephone body 1. Further, as shown in FIG. 3, the telephone body 1 is provided with an unlocking button 10 which will be described later in more details on the upper part of the side wall of the telephone body 1. It should be noted that the handset 2 is placed on the telephone body 1 at such a properly determined position that operator's fingers can reach the lower area of the grasping portion 2f, that is, an operator can take up the hand set 2 from the telephone body 1. Incidentally, the pair of engagement blocks 100 and 100' disposed on both the side faces 1b and 1c of the trapezoidal portion 1a of the telephone body 1 are designed in the same structure. Since both the engagement blocks 100 and 100' function in the same manner, the same components constituting the engagement block 100 as those of the engagement block 100' are identified by the same reference numerals with a prime mark attached thereto respectively and their detailed description with respect to function and structure will not be required. As shown in FIGS. 4 to 6, the engagement block 100 includes a block body 102 the fore end of which is designed in the form of a pawl 101. The block body 102 is formed with an elongated hole 103 in the longitudinal direction. As will be best seen in FIG. 5, a cam face 104 is formed at the position located behind the elongated hole 103 in the side wall of the block 100 (rightwards relative to the latter as seen in the drawing). Each of the engagement blocks 100 and 100' is disposed to slidably move in both the leftward and rightward directions as seen in FIG. 4, that is, in the direction at a right angle relative to the direction of mounting and dismounting of the handset 2 to and from the telephone body 1 (in the direction as identified by arrow marks W - W in the drawing) in the space as defined by the combination of a ceiling wall 11, side guide plates 12 depending from the ceiling wall 11 and a cover plate 13 bridged between both the lower ends of the side guide plates 12 of the telephone body 1. As will be best seen in FIG. 6, a tongue 14 is fitted into each of the elongated holes 103 and 103' of the engagement blocks 100 and 100' while extending therethrough. With respect to the engagement block 100 disposed on the sending side in the left-hand area as seen in FIG. 4 to function as first engagement block a compression coil spring 15 is interposed between the tongue 14 and the rear face of the pawl 101 whereby the engagement block 100 is normally biased in the leftward direction as seen in the drawing under the effect of resilient force of the compression coil spring 15. On the other hand, with respect to the engagement block 100' disposed on the receiving side in the righthand area in FIG. 4 to function as second engagement block a compression coil spring 17 is interposed between a central partition plate 16 located behind the engagement block 100' and the rear end face of the latter whereby the engagement block 100' is normally biased in the rightward direction as seen in the drawing under the effect of resilient force of the compression coil spring 17. It should be noted that the engagement block 100' on the receiving side is biased under the effect of a higher intensity of resilient force than that of the engagement block 100 on the sending side. Further, it should be noted that the pawls 101 and 101' of the engagement blocks 100 and 100' on both the sending and receiving sides are inhibited from projecting from the end faces 1b and 1c of the trapezoidal portion 1a in excess of a predetermined distance toward the area located above the cradles 3 and 4 due to the existence of the tongue 14 which is fitted into the elongated holes 103 and 103'. As shown in FIG. 6, the pawl 101 of the engagement block 100 is designed in the tapered structure including a larger inclined face 101a and a smaller inclined face 101b. Further, the engagement block 100 has an engagement face 101c on the bottom of the pawl 101, the engagement face 101c extending from the smaller inclined face 101b in the rearward direction (in the rightward direction as seen in the drawing), that is, in the direction of movement of the engagement block 100. As shown in FIG. 4, the larger inclined face 101a' of the engagement block 100' on the receiving side is oriented rightwards and extends upwardly at a certain inclination angle. Next, description will be made below as to the hook button 9 with reference to FIG. 6. As will be apparent from the drawing, the hook button 9 includes a button body 9a vertically slidably fitted into a chamber 18 which is formed in the cradle 4 on the sending side and it is normally biased upwardly under the effect of resilient force of a compression coil spring 19 which is accommodated in the hollow space of the button body 9a. As shown in FIG. 4, the hook button 9 is provided with an arm 9b which extends downwardly of the button body 9a. A magnet 9c is fixedly attached to the lower end of the arm 9b. Further, the telephone body 1 is equipped with a lead switch 30 in the area located below the hook button 9, the lead switch 30 serving as a hook switch for switching from the operative state to the inoperative state and vice versa. Thus, a hook switch mechanism 40 is constituted by the combination of hook button 9, compression spring 19 and lead switch 30. Next, description will be made below as to the unlocking button 10 with reference to FIGS. 5 and 7. The unlocking button 10 comprises a button portion 20 and a rod 21 extending from the inside wall of the button portion 20 toward the side wall of the engagement block 100 on the sending side and the fore end of the rod 21 comes in contact with cam face 104 of the engagement block 100. The button portion 20 is slidably fitted into an opening 22 which is formed on the side wall of the telephone body 1 at the position in the proximity of the upper edge thereof, the opening 22 extending at a right angle relative to the direction of movement of the engagement block 100. A compression spring 23 is interposed between the button portion 20 and the side guide plate 12 whereby the unlocking button 10 is normally biased outwardly of the body 1 (in the rightward direction as seen in FIG. 7) under the effect of resilient force of the compression spring 23. Incidentally, reference numeral 24 designate a stopper pawl which serves to inhibit the unlocking button 10 from being sprung outwardly of the telephone body 1. As shown in FIG. 4 which illustrates the inoperative state where the handset 2 is placed on the telephone body 1, the pawls 101 and 101' of the engagement blocks 100 and 100' on both the sending and receiving sides are engaged to the engagement recess 7 on the receiving section 5 and the engagement recess 8 on the sending section 6. At this moment the fore end 101d of the pawl 101 of the engagement block 100 on the sending side comes in engagement against the rear face 8a of the engagement recess 8, while the engagement face 101c of the pawl 101 comes in contact with the engagement portion 8b of the engagement recess 8. As is apparent from the drawing, the engagement portion 8b occupies a small area in the engagement recess 8 which is located opposite to the engagement face 101c of the pawl 101. Specifically, the engagement portion 8b is designed in the form of a plane extending in the longitudinal direction of the handset 2 in the same manner as the engagement face 101c of the pawl 101. By virtue of the arrangement made in that way it is assured that the handset 2 is inhibited from being unintentionally disengaged from the telephone body 1, because the engagement portion 8b in the engagement recess 8 is locked by means of the engagement face 101c so as not to cause any upward displacement of the engagement portion 8b when an operator takes up the handset 2 from the telephone body 1. Since the sending section 6 of the handset 2 is normally urged upwardly by means of the hook button 9 as mentioned above, it results that the engagement portion 8b is brought in tight contact with the engagement face 101c of the pawl 101. Thus, there is no fear of causing rattling movement of the handset 2 under any vibratory condition. Further, since the engagement block 100 on the receiving side is biased with an intensity of resilient force higher than that of the engagement block 100' on the sending side as mentioned above, the handset 2 is caused to forcibly move in the rightward direction as seen in FIGS. 3 and 4 until the inside face 6a of the sending section 6 abuts against the left-hand end face 1c of the trapezoidal portion 1a of the telephone body 1. As a result, the handset 2 is inhibited from an occurrence of rattling movement. While the handset 2 is properly placed on the telephone body 1, the button body 9a of the hook button 9 is forcibly depressed in the chamber 18 against resilient force of the compression spring 19 by means of the sending section 6 of the handset 2, as shown in FIG. 4. At this moment the magnet 9c moves to the position located in the vicinity of the lead switch 30. This causes the lead switch 30 to be opened under the influence of magnetic force whereby the telephone becomes inoperative. When an operator wants to take up the handset 2 from the telephone body 1, he is required to depress the unlocking button 10. When the unlocking button 10 is displaced in the direction as identified an arrow mark X in FIG. 5, the fore end of the rod 21 on the unlocking button 10 comes in slidable contact with the cam face 104 of the engagement block 100 on the sending side whereby the engagement block 100 is displaced toward the central part of the telephone body 1 in the direction as identified by an arrow mark Y. This causes the engagement face 101c of the pawl 101 of the engagement block 100 to be disengaged from the engagement portion 8b of the engagement recess 8 on the sending section 6 of the handset 2, resulting in the sending section 6 of the handset 2 being raised up under the effect of upward resilient force of the hook button 9. At this moment disengagement of the sending section 6 of the handset 2 achieved in that way is followed by disengagement of the receiving section 5 of the same. Now, the handset 2 is ready to be removed or taken up from the telephone body 1. Alternatively, removal of the handset 2 from the telephone body 1 may be carried out by displacing the handset 2 against resilient force of the engagement block 100' on the receiving side in the leftward direction as seen in FIGS. 3 and 4. Due to the fact that the pawl 101 of the engagement block 100 on the sending side is inhibited from projection into the area located above the cradle 4 on the sending side in excess of a predetermined distance because of the existence of the tongue 14, the pawl 101 of the engagement block 100 can be disengaged from the engagement recess 8 by displacing the handset 2 in the leftward direction. Thereafter, the sending section 6 of the handset 2 is raised up under the effect of upward resilient force of the hook button 9 and the sending receiving section 5 of the same is then released from the engaged state. Now, the handset 2 is ready to be removed or taken up from the telephone body 1. Further, as another method of removing or taking up the handset 2 from the telephone body 1 removal or taking-up of the handset 2 may be achieved by way of the steps of displacing the receiving section 5 of the handset 2 in the upward direction by operator' s force, allowing the lower edge 7a of the engagement recess 7 as shown in FIG. 4 to come in slidable contact with the larger inclined face 101a' of the engagement block 100' on the receiving side, displacing the engagement block 100' in the leftward direction as seen in the drawing until the engagement block 100' is disengaged from the receiving section 5 and thereafter disengaging the sending section 6 from the engagement block 100. Once the handset 2 is removed from the telephone body 1 in accordance with one of the above-mentioned various methods, the hook button 9 is released from the depressed state which is maintained by the dead weight of the sending section 6 and thereafter it is displaced upwardly under the effect of resilient force of the compression spring 19. Thus, the magnet 9c is parted away from the lead switch 30 and thereby the lead switch 30 is closed. This leads to a result that the telephone becomes operative. On the other hand, when the handset 2 is placed on the telephone body 1, it is forcibly depressed on the latter by operator's hand in such a manner that the receiving section 5 of the handset 2 is located opposite to the cradle 3 on the receiving side while the sending section 6 of the same is located opposite to the cradle 4 on the sending side. Thereafter, the pawl 101' of the engagement block 100' on the receiving side is caused to move forward beyond the inside face 5b of the receiving section 5 until it is fitted into the engagement recess 7 and at the same time the pawl 101 of the engagement block 100 on the sending side is caused to move forward beyond the inside face 6b of the sending section 6 until it is fitted into the engagement recess 8 whereby the handset 2 is firmly held on the body 1. At this moment the button body 9a of the hook button 9 is depressed into the chamber 18 by means of the projected part of the sending section 6 and thereby the telephone becomes inoperative again by turning off the lead switch 30. Next, other embodiment of the present invention will be described below with reference to FIG. 8. In this embodiment the engagement block 200 for the sending side disposed leftsides relative to the side guide plates 212 as seen in the drawing is fixedly provided with a leaf spring 215. Both the ends 215a and 215b of the leaf spring 215 are attached to the ceiling wall 11 whereby the engagement block 200 is normally biased in the leftward direction as seen in the drawing under the effect of restorative resilient force of the leaf spring 215. As is apparent from the drawing, the engagement block 200 is formed with a cam face 204 on the one side wall thereof and an unlocking button 10 is disposed at the position located opposite to the cam face 204. The structure of the unlocking button 10 is entirely the same as that shown in FIGS. 2 to 7 and moreover the manner of actuating the engagement block 200 by operating the unlocking button 10 is entirely the same as that in the foregoing embodiment. On the other hand, the engagement block 200' for the receiving side disposed rightwards relative to the side guide plates 212 as seen in the drawing is fixedly provided with a leaf spring 217 and both the ends 217a and 217b of the leaf spring 217 are attached to the ceiling wall 11 whereby the engagement block 200' is normally biased in the rightward direction as seen in the drawing under the effect of restorative resilient force of the leaf spring 217. The handset 2 is firmly held on the telephone body 1 by cooperative function of the engagement blocks 200 and 200'. Next, another embodiment of the present invention will be described below with reference to FIG. 9. In this embodiment the engagement block 300 on the sending side is provided with an actuating member 320 which extends from the one side wall of the engagement block 300 toward the side wall of the telephone body 1. The one end 320a of the actuating member 320 is projected outwardly of an opening 321 which is formed on the one side wall of the telephone body 1. When the end part 320a of the actuating member 320 is displaced in the direction as identified by an arrow mark Z in the drawing, the engagement block 300 on the sending side is caused to move in the rightward direction as seen in the drawing, that is, in the direction as identified by an arrow mark Z whereby the handset 2 is disengaged from the telephone body 1. It should be noted that the manner of disposing the engagement block 300' on the receiving side as well as the manner of actuating it are entirely same the as those relative to the engagement block 100' in the embodiment as shown in FIGS. 2 to 7. FIGS. 10 and 11 illustrate a modified structure in which the hook button 9 adapted to displace the handset 2 in the vertical direction in accordance with the embodiment as shown in FIGS. 2 to 7 is modified. In the case of the embodiment as shown in FIG. 10 an arrangement is made such that a button 90 is slidably accommodated in the chamber 18 which is formed in the cradle 4 on the sending side and a compression spring 19 is interposed in the hollow space as defined between the button 90 and the bottom wall 18a of the chamber 18 in order to displace the sending section 6 upwardly by means of the button 90 under the effect of resilient force of the compression spring 19. On the other hand, in the case of the embodiment as shown in FIG. 11 a chamber 180 formed in the cradle 4 on the sending side is filled with a block 95 made of elastomeric material. The block 95 is fixedly secured to the bottom of the chamber 180 with the aid of an adhesive or the like means in order to inhibit it from being removed from the chamber 180. As will be apparent from the drawing, the block 95 is held in the compressed state under the influence of dead weight of the sending section 6 and the latter is normally urged in the vertical direction under the effect of restorative resilient force of the block 95. It should of course be understood that a distance of displacement of the button 90 from the loaded state to the unloaded state in the embodiment as shown in FIG. 10 as well as a distance of displacement of the elastic block 95 from the loaded state to the unloaded state in the vertical direction in the embodiment as shown in FIG. 11 are so determined that the lower edge 8c of the engagement recess 8 can be raised up above the foremost end 101d of the pawl 101 of the engagement block 100. Next, description will be made below as to other embodiment of the present invention as shown in FIG. 12. In this modified embodiment the pawl 401 of the engagement block 400 has an inclined face 401a which extends toward the foremost end 401b at a certain downward inclination angle and moreover it has an engagement face 401c which extends from the foremost end 401b of the pawl 401 in the direction of movement of the engagement block 400. On the other hand, the engagement recess 80 has a face which extends from the rear wall 80a thereof in the direction of movement of the engagement block 400 whereby an engagement portion 80b is constituted by the aforesaid face. Further, the engagement recess 80 has an inclined face 80c which extends from the right-hand edge of the engagement portion 80b at a certain downward inclination angle as seen in the drawing. While the handset 2 is held at the illustrated inoperative state, the engagement face 401c of the engagement block 400 is engaged to the engagement portion 80b of the engagement recess 80, resulting in the handset 2 being firmly placed on the telephone body 1. In this embodiment removal of the handset 2 from the telephone body 1 is achieved by way of the steps of displacing the engagement block 400 in the rightward direction by a distance corresponding to the depth of the engagement portion 80b in the engagement recess 80 and causing the foremost end 401b of the pawl 401 to move in the rightward direction in conformance with the inclined face 80c of the engagement recess 80 until it moves beyond the ridge 6b' of the sending section 6 while the handset 2 is raised up under the effect of resilient force of the hook button 9. On the other hand, placing of the handset 2 on the telephone body 1 is achieved by way of the steps of locating the sending section 6 above the cradle 4 on the sending side, depressing the handset 2 on the cradle 4 so as to allow the ridge 6b' of the sending section 6 to come in slidable contact with the tapered face 401a of the engagement block 400, displacing the engagement block 400 in the rightward direction as seen in the drawing until the foremost end 401b of the pawl 401 moves beyond the ridge 6b' and finally causing the pawl 401 to be introduced into the engagement recess 80. In the case of another embodiment of the present invention as shown in FIG. 13 the engagement recess 70 in the receiving section 5 has an inclined face 70a in the lower area which extends toward the opened side (in the leftward direction as seen in the drawing) at a certain downward inclination angle. The engagement block 500 on the receiving side includes a pawl 501 of which foremost end is designed in the flat shape and the lower edge 501a of the foremost end of the pawl 501 is adapted to abut against the inclined face 70a of the engagement recess 70 whereby the handset 2 is held in position on the telephone body 1. As the handset 2 is raised up from the illustrated state, the engagement block 500 is forcibly displaced in the leftward direction as seen in the drawing by means of the inclined face 70a and thereafter the pawl 501 moves beyond the ridge 5b' of the receiving section 5. Now, the handset 2 is ready to be taken up from the telephone body 1. On the other hand, holding of the handset 2 on the telephone body 1 is achieved by way of the steps of depressing the receiving section 5 toward the cradle 3 on the receiving side, causing the ridge 5b' of the receiving section 5 to thrust the engagement block 500 in the leftward direction until the ridge 5b' moves beyond the pawl 501 and finally causing the pawl 501 to be introduced into the engagement recess 70. Finally, description will be made below as to a modified embodiment of the present invention as shown in FIG. 14. In this embodiment an engagement block 600 on the receiving side is supported turnable about a shaft 601 which is horizontally held in the telephone body 1. The engagement block 600 is normally turned in the direction as identified by an arrow mark P under the effect of resilient force of a helical torsion spring 602 which is spanned between the shaft 601 and the engagement block 600 and a pawl 603 of the latter is projected into an engagement recess in the cradle on the receiving side. As is apparent from the drawing, the pawl 603 of the engagement block 600 includes a lower inclined face 603a which extends in the rightward direction at a certain upward inclination angle and an upper inclined face 603b which extends in the rightward direction as seen in the drawing at a certain downward inclination angle. The engagement block 600 is formed with a projection 604 which is adapted to abut against a stopper 11a on the inside surface of the ceiling wall 11 of the telephone body 1. Thus, a distance of projection of the pawl 603 outwardly of the trapezoidal portion 1a is restricted by abutment of the projection 604 against the stopper 11a in that way. To firmly hold the handset 2 on the telephone body 1 the receiving section 5 is first located above the cradle 3 on the receiving side and it is then depressed toward it. Thus, the ridge 5a of the receiving section 5 comes in slidable contact with the upper inclined face 603b of the pawl 603 whereby the engagement block 600 is caused to turn in the anticlockwise direction against resilient force of the helical torsion spring 602. When the ridge 5a moves beyond the foremost end 603c of the pawl 603, the latter is introduced into the engagement recess 7. As a result, the handset 2 is firmly held on the telephone body 1. On the other hand, when the receiving section 5 is raised up, the lower edge 7a of the opened side of the engagement recess 7 comes in slidable contact with the lower inclined face 603a of the pawl 603 whereby the latter is displaced in the leftward direction as seen in the drawing. When the ridge 5a of the receiving section 5 moves beyond the pawl 603, the latter is disengaged from the engagement recess 7. Now, the handset 2 is ready to be removed from the telephone body 1. While the present invention has been described above with respect to typical preferred embodiments thereof, it should of course be understood that it should not be limited only to them but various changes or modifications may be made in any acceptable manner without departure from the spirit and scope of the invention as defined by the appended claims.

An improved telephone set of the type including a telephone body and a handset adapted to be placed on the former wherein the telephone set includes features which prevents displacement of the handset from the telephone body. The telephone body has a pair of engagement blocks incorporated therein of which part is projected outwardly of the telephone body and they are fitted into engagement recesses on the handset whereby the latter is firmly placed on the telephone body. At least the one engagement block has an engagement face which is adapted to come in contact with the engagement portion in the corresponding engagement recess, wherein each engagement block includes a pawl portion. Displacement of the handset occurs by displacing one of the pawl portions out of its respective engagement recess followed by displacement of the handset in a second direction which is different from the first direction which causes the displacement of the other pawl portion out of its respective engagement recess. Thus, the handset is reliably held on the telephone body.

FIELD OF THE INVENTION [0001] The present invention relates to an information processing apparatus, control method therefor, computer program, and storage medium. BACKGROUND OF THE INVENTION [0002] A software failure at a low recall ratio is often dealt with by obtaining a software processing log. The processing log is conventionally obtained by correcting an application software module and adding a processing log obtaining routine. The method which requires correction of application software such as embedding of a log obtaining code complicates correction processing. [0003] Against this background, there is proposed a method capable of obtaining a processing log by providing a log obtaining module without performing any complicated correction of application software itself (see Japanese Patent Application Laid-open No. 2004-38311). In software divided into a plurality of modules; the log obtaining module mediates a call for a function present in a given module from a module corresponding to application software, and obtains a processing log in the given module which responds to the call. [0004] Processes executed in the software include processes which must always call a predetermined end function after a call for a function whose operation is paired with that of the end function, such as memory allocation/memory free or the start of a device/the end of the device. At this time, if processing which has not ended because its end function has not been called remains, the processing influences execution of another processing. Thus, it must be reliably determined whether an end function has been called. SUMMARY OF THE INVENTION [0005] It is an object of the present invention to make it possible to determine whether processing by functions whose operations are paired has normally ended. [0006] According to one aspect of embodiments of the present invention, an information processing apparatus which executes a first module, a second module, and a third module for mediating a call from the first module to a function in the second module and obtaining a log of processing in the second module in response to the call comprises a log obtaining unit which obtains the log from the third module, an extraction unit which extracts, from the obtained log, attribute information of functions and identifiers assigned to the functions, and an end determination unit which determines, on the basis of attribute information of a first function and a second function among the extracted functions, identifiers assigned to the first function and the second function, whether the processing in the second module has normally ended. [0007] Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof. BRIEF DESCRIPTION OF THE DRAWINGS [0008] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. [0009] FIG. 1 is a block diagram showing an example of the configuration of an information processing apparatus according to an embodiment of the present invention; [0010] FIG. 2 is a view for explaining a case wherein software divided into a plurality of modules is loaded into the memory of the information processing apparatus according to the embodiment of the present invention; [0011] FIG. 3 is a view showing an example of the memory configuration of the information processing apparatus when a function call is mediated using IAT Patch as a log obtaining code according to the embodiment of the present invention; [0012] FIG. 4 is a timing chart showing an example when IAT Patch processing is executed in the information processing apparatus according to the embodiment of the present invention; [0013] FIG. 5 is a view showing an example of operation when an executable file EXE is executed in the information processing apparatus according to the embodiment of the present invention; [0014] FIG. 6 is a view showing an example of a memory configuration when the executable file EXE creates an interface instance exported to a COM server in the information processing apparatus according to the embodiment of the present invention; [0015] FIG. 7 is a view showing the memory configuration of the information processing apparatus according to the embodiment of the present invention; [0016] FIG. 8 is a timing chart showing an example when VTable Patch processing is executed in the information processing apparatus according to the embodiment of the present invention; [0017] FIG. 9 is a view showing an example of operation when the executable file EXE is executed in the information processing apparatus according to the embodiment of the present invention; [0018] FIG. 10 is a view showing an example of processing subjected to a handle check when handle check processing is performed in the information processing apparatus according to the embodiment of the present invention; [0019] FIG. 11 is a view showing an example of a handle attribute definition file according to the embodiment of the present invention; [0020] FIG. 12 is a view showing another example of processing subjected to the handle check when handle check processing is performed in the information processing apparatus according to the embodiment of the present invention; [0021] FIG. 13 is a view showing another example of the handle attribute definition file according to the embodiment of the present invention; [0022] FIG. 14 is a flowchart when a handle check application is executed to perform log analysis processing in the information processing apparatus according to the embodiment of the present invention; and [0023] FIG. 15 is a table showing an example of a processing result display window displayed on a display 8 in step 1421 in the flowchart of FIG. 14 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0024] Preferred embodiments of the present invention will now be described in detail in accordance with the accompanying drawings. [0025] FIG. 1 is a block diagram showing an example of the configuration of an information processing apparatus according to an embodiment. For descriptive convenience, the information processing system is constructed in one PC in the embodiment. However, characteristic features of the present invention are effective regardless of whether the information processing system is constructed in one PC or in a plurality of PCs as a network system. [0026] The information processing apparatus comprises a CPU 1 , chipset 2 , RAM 3 , harddisk controller 4 , display controller 5 , harddisk drive 6 , CD-ROM drive 7 , and display 8 . The information processing apparatus incorporates a signal line 11 which connects the CPU 1 and chipset 2 , a signal line 12 which connects the chipset 2 and RAM 3 , a peripheral bus 13 which connects the chipset 2 and various types of peripheral devices 4 and 5 , a signal line 14 which connects the harddisk controller 4 and harddisk drive 6 , a signal line 15 which connects the harddisk controller 4 and CD-ROM drive 7 , and a signal line 16 which connects the display controller 5 and display 8 . [0027] To explain the information processing apparatus according to the embodiment, how to load, into a memory in a normal state, software which is divided into a plurality of modules will be explained with reference to FIG. 2 . FIG. 2 is a view showing an example of the internal configuration of the RAM. [0028] In general, software divided into a plurality of modules exists separately as an executable file EXE ( 23 ) which controls the overall operation, and a dynamic link library DLL ( 27 ) which exists as a module and plays a complementary role of EXE. Both EXE and DLL are loaded into the RAM 3 . EXE is made up of a code segment ( 28 ), data segment ( 29 ), and import function address table ( 22 ). The import function address table is subdivided into DLLs ( 21 and 24 ) to which functions belong. Each DLL holds an address at which each function is loaded ( 30 to 35 ). [0029] The entities of the functions in the DLLs are loaded for the respective DLLs ( 25 and 26 ), and the functions are loaded as parts of corresponding DLLs ( 36 to 41 ). In FIG. 2 , one EXE uses functions in two dynamic link libraries for A.DLL and B.DLL. Functions used actually are six functions: Func AA, Func AB, Func AC, Func BA, Func BB, and Func BC. [0030] When a code in the code segment 28 of EXE calls the function Func AA, a Func AA address ( 30 ) that is written in the import function address table is read. In practice, the address of a Func AA code ( 36 ) which is read as part of A.DLL is written. By calling the address, the EXE code can call Func AA of A.DLL. [0031] An example of the memory configuration of the information processing apparatus when a function call is mediated using IAT Patch (Import Address Table Patch) as a log obtaining code will be explained with reference to FIG. 3 . [0032] After the start of obtaining a log, C.DLL ( 58 ) serving as an IAT Patch DLL is loaded into the memory. C.DLL rewrites the addresses of functions written in an import function address table ( 52 ) into those ( 61 to 66 ) of log obtaining codes Func CAA, Func CAB, Func CAC, Func CBA, Func CBB, and Func CBC in C.DLL. The codes ( 73 to 78 ) of Func CAA, Func CAB, Func CAC, Func CBA, Func CBB, and Func CBC in C.DLL record logs, and call corresponding functions Func AA, Func AB, Func AC, Func BA, Func BB, and Func BC ( 67 to 72 ) which have been loaded in the memory and wait for function calls. [0033] FIG. 4 is a timing chart showing IAT Patch processing in FIG. 3 . For descriptive convenience, FIG. 4 shows an example of how the log obtaining code based on IAT Patch operates when EXE calls Func AA in A.DLL. The same processing is also performed for another function. [0034] When EXE ( 91 ) calls Func AA ( 94 ), a log obtaining code in C.DLL saves a DLL name and function name in the memory, saves the call time in the memory, saves parameters upon the call in the memory, and saves memory contents represented by pointer parameters upon the call in the memory ( 95 ). After that, C.DLL calls Func AA in A.DLL ( 93 ) that is supposed to be called ( 96 ). Func AA processing ( 97 ) in A.DLL ends, and control returns to C.DLL ( 98 ). C.DLL saves the return time in the memory, saves the return value in the memory, and saves memory contents represented by pointer parameters upon return in the memory ( 99 ). C.DLL writes the saved log information in a file ( 100 ), and control returns to EXE as if Func AA of A.DLL normally ended ( 101 ). [0035] FIG. 5 is a view showing an example of operation when the executable file EXE is executed in the information processing apparatus according to the embodiment. In general, an executable EXE ( 113 ) calls functions in DLL- 1 ( 116 ) and DLL- 2 ( 117 ). In FIG. 5 , a log obtaining code called an API tracer is embedded ( 114 ) to generate a processing log ( 115 ). The API tracer operates on the basis of a file ( 111 ) which describes the function definitions of DLL- 1 and DLL- 2 , and a setup scenario ( 112 ) representing a DLL and a function in the DLL for which an import function table is rewritten to obtain a log. [0036] FIG. 6 is a view showing an example of a memory configuration when an executable file EXE ( 118 ) creates an interface instance exported to a COM (Component Object Model) server in the information processing apparatus according to the embodiment. [0037] In general, when an interface instance is created, requested interfaces ( 121 and 122 ) and their methods ( 130 to 135 ) are created in the COM server, and loaded into the memory. Virtual address tables ( 118 and 120 ) are created for created interfaces, and passed to EXE which has requested the creation. The virtual address tables hold addresses ( 124 to 129 ) created for the respective methods. EXE utilizes these pieces of information, and calls the interfaces. In FIG. 6 , one EXE creates two interface instances for Interface A and Interface B, and utilizes methods in the interfaces. Methods used actually are Method AA, Method AB, Method AC, Method BA, Method BB, and Method BC. [0038] When the EXE code calls the function Method AA, a Method AA address ( 124 ) written in the virtual address table is read. The address ( 124 ) describes the address of a Method AA code ( 130 ) which is created as part of Interface A in the COM server. By calling the address, the EXE code can call Method AA of Interface A. [0039] FIG. 7 is a view showing the memory configuration of the information processing apparatus according to the embodiment. This memory configuration is different from that in FIG. 6 in that a method call is mediated using VTable Patch (Virtual address Table Patch) as a log obtaining code. [0040] After the start of obtaining a log, a VTable Patch DLL ( 143 ) is loaded into the memory. The DLL rewrites the addresses of methods written in virtual address tables ( 136 and 138 ) into those ( 145 to 150 ) of log obtaining codes Method A′A, Method A′B, Method A° C., Method B′A, Method B′B, and Method B° C. in the DLL. The codes ( 157 to 162 ) of Method A′A, Method A′B, Method A° C., Method B′A, Method B′B, and Method B° C. in the DLL record logs, and call Method AA, Method AB, Method AC, Method BA, Method BB, and Method BC ( 151 to 156 ) which have been loaded in the memory and wait for method calls. [0041] FIG. 8 is a timing chart showing VTable Patch processing in FIG. 7 . For descriptive convenience, FIG. 8 shows an example of how the log obtaining code based on VTable Patch operates when EXE calls Method AA of Interface A in the COM server. The same processing is also performed for another function. [0042] When EXE ( 163 ) calls Method AA ( 166 ), a log obtaining code in the DLL saves a module name, interface name, and method name in the memory, saves the call time in the memory, saves parameters upon the call in the memory, and saves memory contents represented by pointer parameters upon the call in the memory ( 167 ). Thereafter, the DLL calls Method AA in the COM server ( 165 ) that is supposed to be called ( 168 ). Method AA processing ( 169 ) in the COM server ends, and control returns to DLL ( 170 ). The DLL saves the return time in the memory, saves the return value in the memory, and saves memory contents represented by pointer parameters upon return in the memory ( 171 ). The DLL writes the saved log information in a file ( 172 ), and control returns to EXE as if Method AA in the COM server normally ended ( 173 ). [0043] FIG. 9 is a view showing an example of operation when the executable file EXE is executed in the information processing apparatus according to the embodiment. In general, an executable EXE ( 176 ) calls methods in COM server- 1 ( 179 ) and COM server- 2 ( 180 ). In FIG. 9 , a log obtaining code called an API tracer is embedded ( 177 ) to generate a processing log ( 178 ). The API tracer operates on the basis of a file ( 174 ) which describes the function definitions of COM server- 1 ( 179 ) and COM server- 2 , and a setup scenario ( 175 ) representing a COM server, an interface in the COM server, and a method for the interface for which a virtual address table is rewritten to obtain a log. [0044] FIG. 10 is a view showing an example of processing subjected to a handle check when handle check processing is performed in the information processing apparatus according to the embodiment. In the embodiment, a handle corresponds to an identifier for identifying a function. [0045] In FIG. 10 , an application ( 1001 ) calls a device control module ( 1005 ) via a log obtaining module ( 1011 ) to control a device ( 1010 ). In FIG. 10 , the application ( 1001 ) corresponds to EXE ( 91 ) in FIG. 4 and EXE ( 163 ) in FIG. 8 . The log obtaining module ( 1011 ) corresponds to C.DLL ( 92 ) in FIG. 4 and DLL ( 164 ) in FIG. 8 . The device control module ( 1005 ) corresponds to A.DLL ( 93 ) in FIG. 4 and the COM server ( 165 ) in FIG. 8 . [0046] An OpenDevice function ( 1002 ) powers on a device ( 1007 ), obtains and ensures a control handle for the device ( 1006 ), and returns the handle to a host application ( 1003 ). [0047] A CloseDevice function ( 1004 ) powers off the device ( 1009 ) on the basis of the handle obtained by the OpenDevice function, and releases the control handle. When the OpenDevice function is used, the CloseDevice function ( 1004 ) must always be called, in order to free the handle area and power off a device. If the paired OpenDevice ( 1002 ) and CloseDevice ( 1004 ) are not called, the device is kept ON and the handle allocation area is not freed. This may pose a problem in executing another application. [0048] FIG. 11 is a view showing an example of a handle attribute definition file according to the embodiment. The handle attribute definition file is held by a handle check application in the information processing apparatus, and used to check the functions in FIG. 10 . A handle attribute definition file ( 1101 ) describes a DLL ( 1102 ) subjected to a handle check, and a function definition file ( 1103 ) for the target DLL. The DLL subjected to a handle check corresponds to the device control module ( 1005 ) in FIG. 10 . The function definition file ( 1103 ) describes information including the return value and parameters of functions in the target DLL, and is used to extract information necessary to perform a handle check from log data stored in the log obtaining module ( 1011 ). The function definition file ( 1103 ) corresponds to the function definitions 111 and 174 in FIGS. 5 and 9 . [0049] In the handle attribute definition file ( 1101 ), handle attribute settings are defined by TraceFunc ( 1104 ), GroupID ( 1105 ), FuncProperty ( 1106 ), and ParaError ( 1107 ) for each function. More specifically, TraceFunc ( 1104 ) sets a function name, and GroupID ( 1105 ) sets a function group which defines a handle attribute. FuncProperty ( 1106 ) sets which of Open, Close, and OpenClose is defined as a handle attribute of the function. ParaError ( 1107 ) can set the return value of the function or which of arguments is defined with the Open/Close attribute. Further, ParaError ( 1107 ) can make a setting of excluding the function from targets of handle check processing when the return value or argument has a specific value. [0050] In FIG. 11 according to the embodiment, TraceFunc=OpenDevice ( 1104 ) defines the OpenDevice function. It is defined that the OpenDevice function belongs to group 0x01 by GroupID=0x01( 1105 ), it has the Open attribute by FuncProperty=0x02 ( 1106 ), the DWORD value serving as a return value is the Open value by ParaError=0.DWORD, 0x02,!=0.0 ( 1107 ), and handle check processing is done only when the value is not 0. [0051] TraceFunc=CloseDevice ( 1108 ) defines the CloseDevice function. It is defined that the CloseDevice function belongs to the same group 0x01 as that of OpenDevice by GroupID=0x01( 1109 ), it has the Close attribute by FuncProperty=0x01( 1110 ), the DWORD value serving as the first argument is the Close value by ParaError=1.DWORD, 0x01,!=0.0 ( 1111 ), and handle check processing is done only when the value is not 0. These definitions provide handle attribute settings of performing a handle check using the return value of the OpenDevice function and the first argument of the CloseDevice function. [0052] FIG. 12 is a view showing another example of processing subjected to the handle check when handle check processing is performed in the information processing apparatus according to the embodiment. FIG. 12 shows a function when an application ( 1201 ) calls a memory allocation module ( 1207 ) via a log obtaining module ( 1216 ) to request an OS ( 1213 ) to allocate/free the memory. In FIG. 12 , the application ( 1201 ) corresponds to EXE ( 91 ) in FIG. 4 and EXE ( 163 ) in FIG. 8 . The log obtaining module ( 1216 ) corresponds to C.DLL ( 92 ) in FIG. 4 and DLL ( 164 ) in FIG. 8 . The memory allocation module ( 1207 ) corresponds to A.DLL ( 93 ) in FIG. 4 and the COM server ( 165 ) in FIG. 8 . [0053] A MemoryAlloc function ( 1202 ) issues a memory allocation request to the OS ( 1208 ), obtains the handle of an allocated memory ( 1209 ), and returns the handle to a host application ( 1203 ). A MemoryFree function ( 1206 ) requests the OS to free the memory ( 1212 ) on the basis of the handle obtained by the MemoryAlloc function. When the MemoryAlloc function is used, the MemoryFree function must always be called, in order to free the memory in the OS. If the paired MemoryAlloc and MemoryFree are not called, the memory is kept allocated in the OS and memory leak occurs. [0054] The above processing is almost the same as that in the example of FIG. 10 , and in FIG. 12 , a MemoryRealloc function ( 1204 ) further exists. The MemoryRealloc function re-allocates the memory ( 1210 ) on the basis of the memory area allocated by the MemoryAlloc function. When the MemoryRealloc function is used, a memory re-allocation request ( 1210 ) is issued to the OS on the basis of the handle of the MemoryAlloc function. The OS performs memory re-allocation processing and returns the handle ( 1211 ). At this time, in the OS, the handle may be identical to or different from that for the original memory depending on the memory allocation status. [0055] FIG. 13 is a view showing another example of the handle attribute definition file according to the embodiment. The handle attribute definition file is held by the handle check application in the information processing apparatus, and used to check the functions in FIG. 12 . [0056] A handle attribute definition file ( 1301 ) contains the same handle attribute settings as the contents shown in FIG. 11 , and definitions ( 1312 to 1316 ) for the MemoryRealloc function having the OpenClose handle attribute. Definitions ( 1304 to 1307 ) for the MemoryAlloc function and those ( 1308 to 1311 ) for the MemoryFree function have the same contents as those in FIG. 11 . [0057] In the definitions of the MemoryRealloc function, the OpenClose attribute is set by FuncProperty=0x04 ( 1314 ). For this reason, ParaError has two settings, and ParaError=1.DWORD,0x01,!=0.0 ( 1315 ) defines that the DWORD value serving as the first argument is the Close value and handle check processing is done only when the value is not 0. [0058] ParaError=0.DWORD, 0x02,!=0.0 ( 1316 ) defines that the DWORD value serving as the return value is the Open value and handle check processing is done only when the value is not 0. These definitions provide handle attribute settings of performing a handle check at the return value of the MemoryAlloc function, the first argument of the MemoryFree function, and the return value and first argument of the MemoryRealloc function. [0059] FIG. 14 is a flowchart when the handle check application is executed to perform log analysis processing in the information processing apparatus according to the embodiment. The handle check application is stored in the HDD 6 in FIG. 1 , read out to the RAM 3 , and executed by the CPU 1 . [0060] The handle check application obtains the log of a DLL subjected to a handle check from the log obtaining module on the basis of the handle attribute definition file shown in FIG. 11 or 13 (S 1401 ). The log contains a handle serving as a function identifier, and function attribute information such as the function name, function group, and handle attribute. [0061] Handle check processing proceeds by checking the obtained log sequentially from the start to end (S 1402 to S 1419 ). It is determined whether a function obtained as the log has been set by the handle attribute definition (S 1403 ). If it is determined that the function has not been defined, the function is not processed. If it is determined that the function has been defined, it is determined which of the Open, Close, and OpenClose attributes is set as the FuncProperty setting in the handle attribute definition file for the function (S 1404 ). [0062] If it is determined that the function has the Open attribute, a handle value is obtained in accordance with the ParaError setting to determine whether the value is a valid handle value (S 1405 ). Whether the value is valid is based on the setting contents of ParaError in the handle attribute definition file. In FIGS. 11 and 13 , the handle attribute definition file defines that handle check processing is done only when the value is not 0. Thus, it is determined that the handle value is valid unless it is 0. [0063] If it is determined that the handle value is invalid, the flow returns to S 1403 to process another function without performing any handle check processing. If it is determined that the handle value is valid, a function having the same GroupID as that of the current function and having a handle of the Open attribute is registered by handle check processing in a handle registration table for registering an unmatched function. Then, if the function is registered, it is determined whether the handle value of the registered function is different from that of the current function (S 1408 ). If the handle value of the registered function and that of the current function coincide with each other, it is determined that the result of Open processing is invalid, and an error flag is set for the function subjected to handle check processing (S 1412 ). If no function has been registered, or the function has been registered but the handle values are different from each other, function information and the handle value of the Open attribute are saved in the handle registration table (S 1411 ). [0064] If the function attribute is the Close attribute, a handle value is obtained in accordance with the ParaError setting to determine whether the value is a valid handle value (S 1406 ). The determination criterion of whether the value is valid is the same as that for the Open attribute. If it is determined that the handle value is invalid, the flow returns to S 1403 to process another function without performing any check processing. If it is determined that the handle value is valid, it is determined whether a function having the same GroupID as that of the current function and having a handle of the Open attribute or OpenClose attribute has been registered in the handle registration table, and whether the handle value is equal to the handle value of the current function (S 1409 ). If no function has been registered in the handle registration table, or the function has been registered but the handle values are different from each other, it is determined that the current processing is Close processing called without any Open processing, and the error flag is set for the function subjected to handle check processing (S 1414 ). If the handle values coincide with each other, the Open and Close processes are normally done, and the function information and handle values in the handle registration table are deleted (S 1413 ). [0065] If the function attribute is the OpenClose attribute, the handle value of the Close attribute is obtained in accordance with the ParaError setting to determine whether the value is a valid handle value (S 1407 ). This determination method is also the same as the above-described one. If it is determined that the handle value is invalid, the flow returns to S 1403 to process another function without performing any check processing. If it is determined that the handle value is valid, it is determined whether a function having the same GroupID as that of the current function and having a handle of the Open attribute has been registered in the handle registration table, and whether the handle value is equal to the handle value of the current function (S 1410 ). [0066] If no function has been registered, or the function has been registered but the handle values are different from each other, it is determined that the current processing is Close processing called without any Open processing, and the error flag is set for the function subjected to handle check processing (S 1415 ). If the handle values coincide with each other, the Open and Close processes are normally done, and the function information and handle values in the handle registration table are deleted (S 1415 ). [0067] The handle value of the Open attribute is obtained in accordance with the ParaError setting to determine whether the value is a valid handle value (S 1417 ). If it is determined that the handle value is invalid, processing for the current function ends, and processing for another function continues in S 1403 . If it is determined that the handle value is valid, the same processing (S 1418 ) as those (S 1408 , S 1411 , and S 1412 ) for a function of the Open attribute is executed. [0068] The above processing is repeated. If all functions registered in the log have undergone handle check processing, functions left in the handle registration table at that time correspond to Open processes for which no Close processing has been done, and the error flag is set for these functions (S 1420 ). [0069] As a result, handle check processing ends for all functions in the log, and the processing results are displayed on the display 8 (S 1421 ). All the functions contained in the log are listed in a processing result display window. For a function for which the error flag has been set in handle check processing, it is displayed that a handle check error has occurred. [0070] FIG. 15 is a table showing an example of the processing result display window displayed on the display 8 in S 1421 of FIG. 14 . Error information is displayed as “x” in the handle check error column ( 1501 ) of the log. For a function with “x”, the error flag is set in handle check processing. [0071] In FIG. 15 , a function on the first line ( 1502 ) of the log represents that the module is HandleCheck.dll, the function is OpenDevice, no argument is set, and the return value is DWORD handle whose value of 0x5034206D. In handle check processing, information on this function is added to the unmatched-function table at this stage. [0072] The second line ( 1503 ) represents a CloseDevice function for Close processing that is paired with the function on the first line. The first argument defined by the Close attribute is 0x5034206D which is equal to the value of the handle check definition on the first line. In this processing, OpenDevice on the first line and CloseDevice on the second line are normally processed. Thus, the function on the first line is deleted from the table, and no error information is displayed in the handle check error column. [0073] For a CloseDevice function on the third line ( 1504 ), the argument has the same value as that of the Open function on the first line that has already been closed by the Close function on the second line. OpenDevice having the same return value as this argument value does not exist in the table. Thus, an error is displayed in the handle check error column. On the fourth line ( 1505 ), MemoryAlloc is executed, and its information is added to the table. However, MemoryAlloc results in an error because MemoryFree serving as Close processing is not called even after handle check processing proceeds to the end of the log. [0074] Also, a MemoryFree function on the seventh line ( 1508 ) results in an error because this function has the same handle value as a MemoryAlloc function on the fifth line ( 1506 ) that has already been closed by a MemoryRealloc function on the sixth line ( 1507 ). A MemoryFree function on the eighth line ( 1509 ) is normally processed because it has the same value as a value which has been re-allocated and opened by the MemoryRealloc function on the sixth line ( 1507 ). [0075] As described above, according to the embodiment, handles serving as the identifiers of paired functions are defined. Processing which has not normally ended can be detected on the basis of an obtained log. [0076] More specifically, according to the embodiment, whether Open/Close processing of a function is not omitted can be checked. A failure in normally ending processing (e.g., a power On/Off failure of a device or memory leak) can be easily detected, decreasing the number of debagging steps and that of evaluation steps. [0077] A characteristic feature of the present invention is to check processing associated with a function/method handle without changing any function/method code. Handle check processing itself is not limited to the above-described method. Other Embodiment [0078] Note that the present invention can be applied to an apparatus comprising a single device or to system constituted by a plurality of devices. [0079] Furthermore, the invention can be implemented by supplying a software program, which implements the functions of the foregoing embodiments, directly or indirectly to a system or apparatus, reading the supplied program code with a computer of the system or apparatus, and then executing the program code. In this case, so long as the system or apparatus has the functions of the program, the mode of implementation need not rely upon a program. [0080] Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the claims of the present invention also cover a computer program for the purpose of implementing the functions of the present invention. [0081] In this case, so long as the system or apparatus has the functions of the program, the program may be executed in any form, such as an object code, a program executed by an interpreter, or script data supplied to an operating system. [0082] Examples of storage media that can be used for supplying the program are a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a CD-RW, a magnetic tape, a non-volatile type memory card, a ROM, and a DVD (DVD-ROM, DVD-R or DVD-RW). [0083] As for the method of supplying the program, a client computer can be connected to a website on the Internet using a browser of the client computer, and the computer program of the present invention or an automatically-installable compressed file of the program can be downloaded to a recording medium such as a hard disk. Further, the program of the present invention can be supplied by dividing the program code constituting the program into a plurality of files and downloading the files from different websites. In other words, a WWW (World Wide Web) server that downloads, to multiple users, the program files that implement the functions of the present invention by computer is also covered by the claims of the present invention. [0084] It is also possible to encrypt and store the program of the present invention on a storage medium such as a CD-ROM, distribute the storage medium to users, allow users who meet certain requirements to download decryption key information from a website via the Internet, and allow these users to decrypt the encrypted program by using the key information, whereby the program is installed in the user computer. [0085] Besides the cases where the aforementioned functions according to the embodiments are implemented by executing the read program by computer, an operating system or the like running on the computer may perform all or a part of the actual processing so that the functions of the foregoing embodiments can be implemented by this processing. [0086] Furthermore, after the program read from the storage medium is written to a function expansion board inserted into the computer or to a memory provided in a function expansion unit connected to the computer, a CPU or the like mounted on the function expansion board or function expansion unit performs all or a part of the actual processing so that the functions of the foregoing embodiments can be implemented by this processing. [0087] As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims. CLAIM OF PRIORITY [0088] This application claims priority from Japanese Patent Application No. 2004-364782 filed on Dec. 16, 2004, which is hereby incorporated by reference herein.

An information processing apparatus executes a first module, a second module, and a third module for mediating a call from the first module to a function in the second module and obtaining the log of processing in the second module in response to the call. The apparatus obtains the log from the third module, extracts, from the obtained log, attribute information of functions and identifiers assigned to the functions, and determines, on the basis of attribute information of a first function and a second function among the extracted functions, identifiers assigned to the first function and the second function, whether processing in the second module has normally ended.

The present application claims the benefit of U.S. Provisional Patent Application No. 60/487,580, filed on Jul. 17, 2003; the present application is also a continuation-in-part of U.S. patent application Ser. No. 10/234,859, filed Sep. 5, 2002 (status pending), which is a continuation-in-part of U.S. patent application Ser. No. 10/036,796, filed Jan. 7, 2002 U.S. Pat. No. 6,843,657, which claims the benefit of U.S. Provisional Patent Application No. 60/260,893, filed on Jan. 12, 2001 and U.S. Patent Application No. 60/328,396, filed on Oct. 12, 2001. Each above identified application is incorporated herein by this reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to electrical interconnection systems, and more specifically, to a high speed, high-density interconnection system for differential and single-ended transmission applications. 2. Discussion of the Background Backplane systems are comprised of a complex printed circuit board that is referred to as the backplane or motherboard, and several smaller printed circuit boards that are referred to as daughtercards or daughterboards that plug into the backplane. Each daughtercard may include a chip that is referred to as a driver/receiver. The driver/receiver sends and receives signals from driver/receivers on other daughtercards. A signal path is formed between the driver/receiver on a first daughtercard and a driver/receiver on a second daughtercard. The signal path includes an electrical connector that connects the first daughtercard to the backplane, the backplane, a second electrical connector that connects the second daughtercard to the backplane, and the second daughtercard having the driver/receiver that receives the carried signal. Various driver/receivers being used today can transmit signals at data rates between 5–10 Gb/sec and greater. The limiting factor (data transfer rate) in the signal path is the electrical connectors that connect each daughtercard to the backplane. Further, the receivers are capable of receiving signals having only 5% of the original signal strength sent by the driver. This reduction in signal strength increases the importance of minimizing cross-talk between signal paths to avoid signal degradation or errors being introduced into digital data streams. With high speed, high-density electrical connectors, it is even more important to eliminate or reduce cross-talk. Thus, a need exists in the art for a high-speed electrical connector capable of handling high-speed signals that reduces cross-talk between signal paths. SUMMARY OF THE INVENTION The present invention provides a high-speed electrical interconnection system designed to overcome the drawbacks of conventional interconnection systems. That is, the present invention provides an electrical connector capable of handling high-speed signals effectively. In one aspect the present invention provides an interconnect system having a first circuit board, a second circuit board and a connector for connecting the first circuit board to the second circuit board. The first circuit board includes (a) a first differential interconnect path, (b) a first signal pad on a surface of the first circuit board and (c) a second signal pad also on the surface of the first circuit board, wherein the first differential interconnect path includes a first signal path electrically connected to the first signal pad and a second signal path electrically connected to the second signal pad. The second circuit board includes a second differential interconnect path. The connector electrically connects the first differential interconnect path with the second differential interconnect path. The connector may include the following: an interposer having a first face and a second face opposite the first face, the first face facing the surface of the first circuit board; a first conductor having an end adjacent to the second surface of the interposer; a second conductor parallel with and equal in length to the first conductor, the second conductor also having an end adjacent to the second surface of the interposer; a dielectric material disposed between the first conductor and the second conductor; a first elongated contact member having a conductor contact section, a board contact section and an interim section between the conductor contact section and the board contact section, the conductor contact section being in physical contact with the end of the first conductor, the board contact section being in physical contact with and pressing against a surface of the first signal pad, but not being secured to the first signal pad, and the interim section being disposed in a hole extending from the first face of the interposer to the second face of the interposer, wherein the first signal pad exerts a force on the first contact member and the first contact member is free to move in the direction of the force to a limited extent. In another aspect, the present invention provides a connector for electrically connecting a signal path on a first circuit board with a signal path on a second circuit board. The connector may include: a first, a second and a third spacer; a first circuit board disposed between the first and second spacers; and a second circuit board disposed between the second and third spacers. The first circuit board has a first face abutting a face of the first spacer and a second face abutting a face of the second spacer. The second face has a set of signal conductors disposed thereon. Each of the signal conductors disposed on the second face has a first end adjacent a first edge of the second face, a second end adjacent a second edge of the second face, and an interim section between the first end and the second end. The second circuit board has a first face abutting a face of the second spacer and a second face abutting a face of the third spacer. The first face of the second circuit board having a set of signal conductors disposed thereon. Each of the signal conductors disposed on the first face having a first end adjacent a first edge of the first face, a second end adjacent a second edge of the first face, and an interim section between the first end and the second end. The first edge of the second face of the first circuit board is parallel and spaced apart from the first edge of the first face of the second circuit board. Advantageously, to reduce cross-talk, none of the first ends of the signal conductors on the first circuit board are aligned with any of the first ends of the signal conductors on the second circuit board. In another aspect, the present invention provides a spacer for a connector. The spacer may include a first face having a set of M grooves disposed thereon, each of the M grooves extending from a first edge of the first face to a second edge of the first face; a second face having a set of N grooves disposed thereon, each of the N grooves extending from a first edge of the second face to a second edge of the second face; and an elongate finger projecting outwardly from a side of the spacer for attaching the spacer to a part of the connector. The above and other features, embodiments and advantages of the present invention, as well as the structure and operation of preferred embodiments of the present invention, are described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated herein and form part of the specification, help illustrate various embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. In the drawings, like reference numbers indicate identical or functionally similar elements. Additionally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears. FIG. 1 is an exploded view of a connector in accordance with an example embodiment of the present invention. FIG. 2 is a view of a printed circuit board according to an embodiment of the present invention. FIG. 3 is a front side view of the printed circuit board shown in FIG. 2 . FIG. 4 is a perspective view of a spacer in accordance with an example embodiment of the present invention. FIG. 5 is a top view of a first face of the spacer shown in FIG. 4 . FIG. 6 is a top view of a second face of the spacer shown in FIG. 4 . FIG. 7 is a front side view of the spacer shown in FIG. 4 . FIG. 8 is a top view of a first face of a second spacer. FIG. 9 is a top view of a second face of the second spacer. FIG. 10 is a perspective view of an apparatus consisting of a circuit board sandwiched between two spacers. FIG. 11 is a front side view of the apparatus shown in FIG. 10 . FIG. 12 illustrates an arrangement of multiple circuit boards and multiple spacers according to an example embodiment of the present invention. FIG. 13 is a top view of a first face of a circuit board according to an embodiment of the present invention. FIG. 14 illustrates how the alignment of the conductors on an A type circuit board differs from alignment of the conductors on a B type circuit board. FIG. 15 illustrates a contact member according to one embodiment of the invention. FIGS. 16 and 17 illustrate a cell according to one embodiment of the invention. FIGS. 18 and 19 illustrate that cells may be configured to fit into an aperture of an interposer. FIG. 20 illustrates a finger of a spacer inserted into a corresponding notch of an interposer. FIG. 21 illustrates the arrangement of the interposers 180 in relation to board 120 and in relation to boards 2190 and 2180 , according to one embodiment FIG. 22 is a cross-sectional view of an embodiment of the connector 100 . FIG. 23 illustrates an embodiment of backbone 150 . FIG. 24 illustrates an embodiment of an end cap 199 . FIG. 25 is an exploded view of backbone 150 and an end cap 199 . FIG. 26 is a view of a backbone 150 and an end cap 199 assembled together. FIG. 27 is a view of a spacer connected to backbone 150 . FIG. 28 illustrates an embodiment of mounting clip 190 b. FIG. 29 is an exploded view of clip 190 b and end cap 199 . FIG. 30 is a view of clip 190 b having an end cap 199 attached thereto. FIG. 31 illustrates an embodiment of shield 160 . FIG. 32 is an exploded view of shield 160 and an interposer 180 . FIG. 33 is a view of shield 160 being connected to an interposer 180 . FIG. 34 is a view of an assembled connector with an interposer 180 and clip 190 a omitted. FIGS. 35 and 36 are different views of an almost fully assembled connector 100 according to one embodiment assembled without cells in FIG. 35 and with 2 cells in FIG. 36 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is an exploded view of a connector 100 in accordance with an example preferred embodiment of the present invention. Some elements have been omitted for the sake of clarity. As illustrated in FIG. 1 , connector 100 may include at least one printed circuit board 120 having electrical conductors printed thereon. In the embodiment shown, connector 100 may further include a pair of spacers 110 a and 110 b , a pair of interposers 180 a and 180 b , a pair of end-caps 190 a and 190 b , a backbone 150 , a shield 160 , and a pair of endplates 190 a and 190 b . Although only one circuit board and only two spacers are shown in FIG. 1 , one skilled in the art will appreciate that in typical configurations connector 100 will include a number of circuit boards and spacers, with each circuit board being disposed between two spacers, as will be described herein. FIG. 2 is a view of printed circuit board 120 . In the embodiment shown, circuit board 120 is generally rectangular in shape. As shown, circuit board 120 may have one or more electrical conductors disposed on a face 220 thereof. In the embodiment shown, board 120 has four conductors 201 , 202 , 203 , and 204 disposed on face 220 . Each conductor 201 – 204 has a first end, a second and an interim section between the first and second ends. The first end of each conductor is located at a point on or adjacent a first edge 210 of face 220 and the second end of each conductor is located at a point on or adjacent a second edge 211 of face 220 . In many embodiments, second edge 211 of face 220 is perpendicular to first edge 210 , as shown in the embodiment illustrated in FIG. 2 . Although not shown in FIG. 2 , there are corresponding electrical conductors on the opposite face of circuit board 120 . More specifically, for each conductor 201 – 204 , there is a conductor on the opposite face that is a mirror image of the conductor. This feature is illustrated in FIG. 3 , which is a front side view of board 120 . As shown in FIG. 3 , conductors 301 – 304 are disposed on face 320 of board 120 , which face 320 faces in the opposite direction of face 220 . As further illustrated, conductors 301 – 304 correspond to conductors 201 – 204 , respectively. When the interconnection system 100 of the present invention is used to transmit differential signals, one of the electrical conductors 201 – 204 and its corresponding electrical conductor on the opposite face may be utilized together to form the two wire balanced pair required for transmitting the differential signal. Since the length of the two electrical conductors is identical, there should be no skew between the two electrical conductors (skew being the difference in time that it takes for a signal to propagate the two electrical conductors). In configurations where connector 100 includes multiple circuit boards 120 , the circuit boards are preferably arranged in a row in parallel relationship. Preferably, in such a configuration, each circuit board 120 of connector 100 is positioned between two spacers 110 . FIG. 4 is a perspective side view of spacer 110 a according to one embodiment of the invention. As shown, spacer 110 a may have one or more grooves disposed on a face 420 thereof, which face 420 faces away from board 120 . In the embodiment shown, face 420 of spacer 110 a has three grooves 401 , 402 and 403 disposed thereon. Each groove 401 – 403 extends from a point at or near a first edge 410 of face 420 to a point at or near second edge 411 of face 420 . In many embodiments, second edge 411 of face 420 is perpendicular to first edge 410 , as shown in the embodiment illustrated in FIG. 4 . As further shown, face 420 of spacer 110 a may have one or more recesses disposed at an edge of face 420 . In the embodiment shown, there are two sets of four recesses-disposed at an edge on face 420 . The first set of recesses includes recesses 421 a–d , and the second set of recesses includes recesses 431 a–d . Each recess 421 a–d is positioned directly adjacent to the end of at least one groove and extends from a point on edge 410 of face 420 to a second point spaced inwardly from edge 410 a short distance. Similarly, each recess 431 a–d is positioned directly adjacent to the end of at least one groove and extends from a point on edge 411 of face 420 to a second point spaced inwardly from edge 411 a short distance. Accordingly, in the embodiment shown, there is at least one recess between the ends of all the grooves. Each recess 421 , 431 is designed to receive the end of spring element (see FIG. 16 , elements 1520 ). Although not shown in FIG. 4 , there may be grooves and recesses on the opposite face 491 of spacer 110 a . In a preferred embodiment, the number of grooves on the first face of a spacer 110 is one less (or one more) than the number of grooves on the second face of the spacer 110 , but this is not a requirement. Similarly, in the preferred embodiment, the number of recesses on the first face of a spacer 110 is two less (or two more) than the number of recesses on the second face of the spacer 110 . This feature is illustrated in FIGS. 5–7 , where FIG. 5 is a top view of face 420 , FIG. 6 is a top view of the opposite face (i.e., face 491 ), and FIG. 7 is a front side view of spacer 110 a. As shown in FIG. 5 , grooves 401 – 403 , recesses 421 a–d , and recesses 431 a–d are disposed on face 420 of spacer 110 a . Similarly, as shown in FIG. 6 , grooves 601 – 604 , recesses 621 a–c , and recesses 631 a–c are disposed on face 491 of spacer 110 a , which face 491 faces in the opposite direction of face 420 . Grooves 601 – 604 are similar to grooves 401 – 404 in that each groove 601 – 604 extends from a point on a first edge 610 of face 491 to a point on a second edge 611 of face 491 . Likewise, recesses 621 and 631 are similar to recesses 421 and 431 . Like each recess 421 , each recess 621 extends from a point on edge 610 of face 491 to a second point spaced inwardly from edge 610 a short distance. Similarly, each recess 631 extends from a point on edge 611 of face 491 to a second point spaced inwardly from edge 611 a short distance. Each recess 621 , 631 is designed to receive the end of a spring element (see FIG. 16 , elements 1520 ). The figures illustrate that, in some embodiments, the number of grooves on one face of a spacer 110 is one less (or one more) than the number of grooves on the opposite face of the spacer. And also show that the number of recesses on one face may be two less (or two more) than the number of recesses on the opposite face. In the embodiment shown in FIGS. 4–6 , each recess on one face is positioned so that it is generally directly opposite an end of a groove on the other face. For example, recess 421 a is generally directly opposite an end of groove 604 and recess 621 a is generally directly opposite an end of groove 403 . This feature can be more easily seen by examining FIG. 7 , which is a front side view of the spacer. Referring back to FIG. 4–6 , FIG. 4 shows that spacer 110 a may further include three fingers 435 , 437 , and 440 . It also shows that that spacer 110 a may also include a slot 444 and a first pair of bosses 450 disposed on and projecting outwardly from face 420 and a second pair of bosses 650 disposed on and projecting outwardly from face 491 . Bosses 650 are provided to fit in the apertures 244 of circuit board 120 . This feature enables board 120 to be properly aligned with respect to the adjacent spacers 110 a and 110 b. Finger 435 is located towards the top of the front side of spacer 110 a and finger 437 is located towards the front of the bottom side of spacer 110 a . Finger 435 projects outwardly from the front side of spacer 110 a in a direction that is perpendicular to the front side of the spacer. Similarly, finger 437 projects outwardly from the bottom side of spacer 110 a in a direction that is perpendicular to the bottom side of the spacer. Fingers 435 , 437 function to attach spacer 110 a to interposers 180 b , 180 a , respectively. More specifically, interposer 180 a includes a recess 1810 (see FIG. 18 ) for receiving and retaining finger 437 . Similarly interposer 180 b includes a recess for receiving and retaining finger 435 . Fingers 435 , 437 each include a protrusion 436 and 438 , respectively. The protrusions are sufficiently resilient to allow them to snap into corresponding recesses in the corresponding interposers. Slot 444 is located towards but spaced apart from the backside of spacer 110 a . Slot 444 extends downwardly from the top side of spacer 110 to form finger 440 . Finger 440 and slot 444 function together to attach spacer 110 a to backbone 150 . Referring back to spacer 100 b (see FIG. 1 ), in the embodiment shown, spacer 110 b is similar but not identical to spacer 110 a . Accordingly, in some embodiments connector 100 includes two types of spacers: type A and type B. In other embodiments, more or less than two types of spacers may be used. FIGS. 8 and 9 further illustrate spacer 110 b (the type B spacer) according to one embodiment. FIG. 8 is a top view of a face 820 of spacer 110 b . Face 820 faces circuit board 120 . As shown in FIG. 8 , face 820 is similar to face 491 of spacer 110 a , which also faces board 120 . Like face 491 , face 820 has four grooves 801 – 804 , a first set of three recesses 821 a–c , and a second set of three recesses 831 a–c. Grooves 801 – 804 are similar to grooves 601 – 604 in that each groove 801 – 804 extends from a point on a first edge 810 of face 820 to a point on a second edge 811 of face 820 . Likewise, recesses 821 and 831 are similar to recesses 621 and 631 . Like each recess 621 , each recess 821 extends from a point on edge 810 of face 820 to a second point spaced inwardly from edge 810 a short distance. Similarly, each recess 831 extends from a point on edge 811 of face 820 to a second point spaced inwardly from edge 811 a short distance. FIG. 9 is a top view of a face 920 of spacer 110 b . Face 920 faces away from circuit board 120 in the opposite direction of face 820 . As shown in FIG. 9 , face 920 is similar to face 420 of spacer 110 a , which also faces away from board 120 . Like face 420 , face 920 has three grooves 901 – 903 , a first set of four recesses 921 a–d , and a second set of four recesses 931 a–d. Grooves 901 – 903 are similar to grooves 401 – 403 in that each groove 901 – 903 extends from a point on a first edge 910 of face 920 to a point on a second edge 911 of face 920 . Likewise, recesses 921 and 931 are similar to recesses 421 and 431 . Each recess 421 extends from a point on edge 910 of face 920 to a second point spaced inwardly from edge 910 a short distance, and each recess 931 extends from a point on edge 911 of face 920 to a second point spaced inwardly from edge 911 a short distance. Spacer 110 b also includes three fingers 835 , 837 , and 840 , a slot 844 , and a pair apertures 850 extending through spacer 110 b . Apertures 850 are provided to receive bosses 650 . This feature enables spacer 110 b to be properly aligned with respect to spacers 110 a. Unlike finger 435 , which is located towards the top of the front side of spacer 110 a , finger 835 is located towards the bottom of the front side of spacer 110 b . Similarly, unlike finger 437 , which is located towards the front of the bottom side of spacer 110 a , finger 837 is located towards the back of the bottom side of spacer 110 b . Finger 835 projects outwardly from the front side of spacer 110 a in a direction that is perpendicular to the front side of the spacer, and finger 437 projects outwardly from the bottom side of spacer 110 a in a direction that is perpendicular to the bottom side of the spacer. Like fingers 435 , 437 , fingers 835 , 837 function to attach spacer 110 b to interposers 180 b , 180 a , respectively. As discussed above, board 120 is positioned between spacers 110 a and 110 b . This feature is illustrated in FIG. 10 . Although not shown in FIG. 10 , bosses 650 of spacer 110 a protrude though apertures 244 of board 120 and through apertures 850 of spacer 110 b . This use of bosses 650 facilitates the proper alignment of spacers 110 a,b and board 120 . When board 120 is properly aligned with the spacers, conductors 201 – 204 and 301 – 304 are aligned with grooves 601 – 604 and 801 – 804 , respectively. This feature is illustrated in FIG. 11 . As shown in FIG. 11 , grooves 601 – 604 , which are disposed on the side of spacer 110 a facing board 120 , are positioned on the spacer to mirror electrical conductors 201 – 204 on printed circuit board 120 . Likewise, grooves 801 – 804 , which are disposed on the side of spacer 110 b facing board 120 , are positioned on the spacer to mirror electrical conductors 301 – 304 . Grooves 601 – 604 and 801 – 804 , among other things, prevent electrical conductors 201 – 204 and 301 – 304 from touching spacer 110 a and 110 b , respectively. In this way, the electrical conductors disposed on board 120 are insulated by the air caught between board 120 and the grooves. Spacers 110 may be fabricated either from an electrically conductive material or from a dielectric material and coated with an electrically conductive layer to electromagnetically shield the electrical conductors of the printed circuit board 120 . Furthermore, the complex impedances of the electrical conductors and their associated grooves can be adjusted by varying the dimensions thereof. Still furthermore, the grooves can include a layer of a dielectric material, such as Teflon, to further adjust the complex impedances of the electrical conductors and their associated channels as well as adjusting the breakdown voltage thereof. Referring now to FIG. 12 , FIG. 12 illustrates an example arrangement of spacers 110 and circuit boards 120 when multiple circuit boards are used in connector 100 . As shown, boards 120 and spacers 110 are aligned in a row in parallel relationship and each circuit board 120 is sandwiched between two spacers 110 . In the example shown, there are two types of circuit boards (A) and (B), as well as the two types of spacers (A) and (B) discussed above. The A type circuit boards are identical to each other and the B type circuit boards are identical to each other. Similarly, The A type spacers are identical to each other and the B type spacers are identical to each other. In the embodiment shown, spacers 110 and boards 120 are arranged in an alternating sequence, which means that between any two given A type spacers there is a B type spacer and vice-versa, and between any two given A type boards there is a B type board and vice-versa. Thus, an A type spacer is not adjacent to another A type spacer and an A type board is not adjacent to another A type board. Accordingly, in this example configuration, each board 120 is disposed between an A type spacer and a B type spacer. As can be seen from FIG. 12 , each face of each board 120 b (the B type board) has three conductors thereon. FIG. 13 is a top view of one face 1320 of a B type board (the other face not shown is a mirror image of face 1320 ). As shown in FIG. 13 , there are three conductors 1301 , 1302 , and 1303 disposed on face 1320 . By comparing FIG. 13 to FIG. 2 (which is a top view of a face of an A type board), one can see that the A and B type boards are nearly identical. One difference being the number of conductors on each face and the alignment of the conductors on the face. In the embodiment shown, the B type boards have one less electrical conductor than do the A type boards. Referring to FIG. 14 , FIG. 14 illustrates how the alignment of the conductors 1301 – 1303 on the B type boards differs from alignment of the conductors 201 – 204 on the A type boards. FIG. 14 shows representative boards 120 a and 120 b in a side by side arrangement so that a front edge 1401 on board 120 a is spaced apart from and parallel with a corresponding front edge 1402 on board 120 b . From FIG. 14 , one can clearly see that the ends of the conductors on the B type board located at edge 1402 are not aligned with the ends of the conductors on the A type board located at edge 1401 . For example, in the example shown, the end of any given conductor on the B type board is interstitially aligned with respect to the ends of two adjacent conductors on the A type board. That is, if one were to draw the shortest line from the end of each conductor on the B board to the adjacent face of the A board, each line would terminate at a point that is between the ends of two conductors on the A board. For example, the shortest line from the end of conductor 1301 to the adjacent face of board 120 a ends at a point that is between the ends of conductors 204 and 203 . An advantage of having the conductors be misaligned is that it may reduce cross-talk in the connector. Referring back to FIG. 12 , one can clearly see that each conductor on each board 120 is aligned with a groove on the spacer directly adjacent the conductor. That is, each groove on each spacer 110 is designed to mirror a corresponding conductor on an adjacent board 120 . Because each conductor is aligned with a corresponding groove, there is a space between the conductor and the spacer. When connector 100 is fully assembled, each conductor on a board 120 comes into physical and electrical contact with two contact members (see FIG. 15 for a representative contact member 1530 a ), an end of each of which fits into the space between the adjacent spacer and the conductor. More specifically, the first end of each conductor comes into physical and electrical contact with the contact portion of a first contact member and the second end of each conductor comes into physical and electrical contact with the contact portion second contact member, and the contact portions of the first and second contact members are each disposed in the space between the corresponding end of the conductor and the spacer. Each contact member functions to electrically connect the conductor to which it makes contact to a trace on a circuit board to which the connector 100 is attached. FIG. 15 illustrates a contact member 1530 a , according to one embodiment of the invention, for electrically connecting a conductor 201 on a board 120 to trace on a circuit board (not shown in FIG. 15 ) to which the connector 100 is attached. Only a portion of contact member 1530 a is visible in FIG. 15 because a portion is disposed within a housing 122 . As shown in FIG. 15 , contact member 1530 a contacts an end of conductor 201 (the spacers and interposers are not shown to better illustrate this feature). In some embodiments, the ends of the conductor 201 are wider than the interim portions so as to provide more surface area for receiving the contact portion of the contact members. Partially shown in FIG. 15 is another contact member 1530 b . Contact member 1530 b has a bottom portion that is also housed in housing 122 . Contact member 1530 b contacts an end of conductor 301 , which can't be seen in FIG. 15 . Housing 122 is preferably fabricated of an electrically insulative material, such as a plastic. The electrical contacts 1530 of each housing 122 can either be disposed within the housing during fabrication or subsequently fitted within the housing. Contact members 1530 may be fabricated by commonly available techniques utilizing any material having suitable electrical and mechanical characteristics. They may be fabricated of laminated materials such as gold plated phosphor bronze. While they are illustrated as being of unitary construction, one skilled in the art will appreciate that they may be made from multiple components. As further shown in FIG. 15 , housing 122 may be configured to hold two elongate springs 1520 a and 1520 b . Springs 1520 extend in the same direction as contact members 1530 and 1531 . The distal end of a spring 1520 is designed to be inserted into a corresponding spacer recess. For example, distal end of spring 1520 a is designed to be received in recess 621 c . The combination of the housing 122 , contact members 1530 , and springs 1520 is referred to as a cell 1570 . FIGS. 16 and 17 further illustrate cell 1570 according to one embodiment. FIG. 17 is an exploded view of cell 1570 . As shown, the housing 122 is generally rectangular in shape and includes apertures 1710 for receiving springs 1520 and apertures 1720 for receiving contact members 1530 . Apertures 1720 extend from the top side of housing to bottom side of the housing so that proximal ends 1641 of contact members 1730 can project beyond the bottom side of housing 122 , as shown in FIG. 16 . Apertures 1710 extend from the top surface of housing 122 towards the bottom surface, but do not reach the bottom surface. Accordingly, when a spring 1520 is inserted into an aperture 1710 the proximal end will not project beyond the bottom surface of housing 122 . While open apertures 1710 are illustrated, it is understood that closed apertures can also be used As illustrated in FIG. 17 , each contact member 1530 , according to the embodiment shown, has a proximal end 1641 and a distal end 1749 . Between ends 1641 and 1749 there is a base portion 1743 , a transition portion 1744 and a contact portion 1745 . Base portion 1743 is between proximal end 1641 and transition portion 1744 , transition portion is between base portion 1743 and contact portion 1745 , and contact portion 1745 is between transition portion 1744 and distal end 1749 . In the embodiment shown, base portion 1743 is disposed in aperture 1720 so that generally the entire base portion is within housing 122 , transition portion 1744 is angled inwardly with respect to the base portion, and distal end 1749 is angled outwardly with respect to the transition portion and therefore functions as a lead-in portion. In a preferred embodiment, the contact portion of a contact member is not fixed to the end of the conductor with which it makes physical and electrical contact. For example, the contact portions are not soldered or otherwise fixed to the board 120 conductors, as is typical in the prior art. Instead, in a preferred embodiment, a contact member 1630 is electrically connected to its corresponding conductor with a wiping action similar to that used in card edge connectors. That is, the contact portion of the contact member merely presses against the end of the corresponding conductor. For example, referring back to FIG. 15 , the contact portion of contact member 1530 a merely presses or pushes against the end portion of conductor 201 . Because it is not fixed to the conductor, the contact portion can move along the length of the conductor while still pressing against the conductor, creating a wiping action. This wiping action may ensure a good electrical connection between the contact members and the corresponding electrical conductors of the printed circuit boards 120 . Referring now to FIGS. 18 and 19 , FIGS. 18 and 19 illustrate that each cell 1570 is designed to fit into an aperture 1811 of an interposer 180 . In the embodiment shown, each interposer 180 includes a first set of apertures 1811 a (see FIG. 19 ) arranged in a first set of aligned rows to create a first row and column configuration and a second set of apertures 1811 b arranged in a second set of aligned rows to create second row and column configuration. In the embodiment shown, each row in the second set is disposed between two rows from the first set. For example, row 1931 , which is a row of apertures 1811 b , is disposed between rows 1930 and 1932 , each of which is a row of apertures 1811 a. As shown in the figures, the second row and column configuration is offset from the first row and column configuration so that the apertures of the second set are aligned with each other but not aligned with the apertures of the first set, and vice-versa An interposer 180 may electromagnetically shield the electrical conductors of the printed circuit boards 120 by being fabricated either of a conductive material or of a non-conductive material coated with a conductive material. As also shown in FIGS. 18 and 19 , interposers 180 include notches 1810 along a top and bottom side. Each notch 1810 is designed to receive the end of a finger of a spacer 110 . Preferably, the finger snaps into a corresponding notch to firmly attach the spacer 110 to the interposer 180 . This feature is illustrated in FIG. 20 . When connector 100 is fully constructed, each aperture in the first and second set receives a cell 1570 . The housing 122 of each cell 1570 has a tab 1633 arranged to fit within a slot 1888 disposed within a corresponding aperture of the interposer 180 , which slot 1888 does not extend the entire length of the aperture. The tab 1633 , therefore, prevents the cell 1570 from falling through the aperture. It is to be understood that the specific shape of the cells and corresponding apertures are merely for exemplary purposes. The present invention is not limited to these shapes. Additionally, when connector is fully constructed, the interposers are arranged so that the contact portion 1745 of each contact member 1530 contacts a corresponding conductor. FIG. 21 illustrates this concept. FIG. 21 illustrates the arrangement of the interposers 180 in relation to board 120 and in relation to boards 2190 and 2180 . The spacers 110 are not shown in the figure to illustrate that board 120 and interposers 180 are arranged so that the front side 2102 of board 120 is aligned with the center line of a column of apertures on spacer 180 b and so that the bottom side 2104 of board 120 is aligned with the center line of a column of apertures on spacer 180 a . FIG. 21 also shows two cells 1570 , each disposed in an aperture of an interposer 180 . As shown in FIG. 21 , a contact member 1530 of each cell 1570 makes physical contact with a corresponding conductor. Although not shown in FIG. 21 , when connector 100 is in use, the proximal end 1641 of each contact member 1530 a,b contacts a conducting element on a circuit board connected to connector 100 . For example, end 1641 of contact member 1530 b contacts a conducting element on circuit board 2190 and end 1641 of contact member 1530 a contacts a conducting element on circuit board 2180 . Accordingly, FIG. 21 illustrates that there is at least one electrical signal path from board 2190 to board 2180 through connector 100 . This electrical signal path includes conductor 214 , contact member 1530 b and contact member 1530 a . As is appreciated by one skilled in the art, connector 100 provides multiple electrical signal paths from board 2190 and 2180 , wherein each signal path includes two contact members 1530 and a conductor on a board 120 . According to the embodiment illustrated in FIG. 21 , each interposer is arranged in parallel relationship with one circuit board connected to connector 100 . More specifically, interposer 180 a is in parallel relationship with circuit board 2180 and interposer 180 b is in parallel relationship with circuit board 2190 . Accordingly, one face of interposer 180 a faces board 2180 and one face of interposer 180 b faces board 2190 . Referring now to FIG. 22 , FIG. 22 is a cross-sectional view of the connector 100 and shows that when connector 100 is in use, as described above, each proximal end 1641 of each contact member 1530 contacts a conducting element 2194 on circuit board 2190 . In a preferred embodiment, each conducting element 2194 is a signal pad, and not a via. Accordingly, in a preferred embodiment, connector 100 is a compression mount connector because each proximal end 1641 merely presses against the circuit board and is not inserted into a via in the circuit board. However, in other embodiments, each element 2194 may be a via or other electrically conducting element. in a preferred embodiment, the board 2190 includes a differential signal path that includes a first signal path 2196 a (e.g., a first trace) and a second signal path 2196 b (e.g., a second trace). As shown, the first pad 2194 is connected to the first signal path 2196 a and the second conducting element 2194 b is is connected to the first signal path 2196 b . It should be noted that the second circuit board 2180 may also have a pair of conducting elements, like elements 2194 , electrically connected to a pair of signal paths, like paths 2196 . As shown in FIG. 22 , a cell 1570 is inserted into an aperture of interposer 180 . As further shown, the distal end of each contact member 1530 of cell 1570 extends beyond the upper face 2250 of the interposer and the proximal end 1641 of each contact member 1530 extends beyond the bottom face 2251 of the interposer, which faces board 2190 and is generally parallel thereto. Each proximal end 1641 presses against a conducting element 2194 on board 2190 . Likewise, each contact portion 1745 of contact member 1530 presses against a conductor on board 120 . Thus, a contact member 1530 electrically connects a conductor on board 120 with a conducting element 2194 on board 2190 . As illustrated in FIG. 22 , the ends of the conductors on board 120 are near the upper face 2250 of interposer. When end 1641 of a contact member 1530 presses against a corresponding element 2194 a normal force caused by the element is exerted on the contact member. Because the contact member 1530 is held firmly within housing 1570 , the normal force will cause housing 122 to move in the direction of the normal force (i.e., away from the circuit board 2190 ). However, springs 1520 limit how far housing 122 will move away from board 2190 because when the housing 122 moves away from board 2190 , springs 1520 will compress and exert a force on the housing in a direction that is opposite of the direction of the normal force caused by board 2190 . This is so because the distal ends of the springs abut a surface of a spacer 110 and the spacer is firmly attached to the interposer 180 , which itself does not move relative to the board 2190 . Thus, springs 1502 will compress and exert a force on housing in a direction opposite the normal force. Referring back to FIG. 1 , each spacer 110 may be configured to attach to an elongate backbone 150 . Additionally, connector 100 may include two end caps 100 a and 100 b , each of which is designed to attach to a respective end of backbone 150 . The backbone 150 and end caps 100 are discussed below. Referring to FIG. 23 , FIG. 23 illustrates an embodiment of backbone 150 . Backbone 150 , according to the embodiment shown, includes bosses 2300 arranged to mate with the end caps 100 as well as slots 2320 , each arranged to receive finger 440 of a spacer 110 , as shown in FIG. 27 . Backbone 150 may further include tines 2330 arranged to mate with the spacers 110 . Referring to FIG. 24 , FIG. 24 illustrates an embodiment of an end cap 199 . End cap 199 , according to the embodiment shown, includes apertures 2402 arranged to mate with bosses disposed on adjacent spacers as well as bosses 2300 disposed on the backbone 150 . The end cap 199 further includes both a screw 2420 and a pin 2410 arranged to mechanically interface connector 100 with a circuit board, which may have a large number of layers, for example, more than 30 layers, as well as a tongue 2430 arranged to mate with an end plate 190 b (see FIGS. 1 and 25 ). While the end cap 199 is illustrated as being symmetrical, that is, can be used on either end of connector 100 , separate left and right-handed end caps may also be used. The screw 2420 and pin 2410 of the end cap 199 may be integrally formed with the end cap 199 or may be attached thereto after fabrication of the end cap 199 . It has been found that it is often necessary to utilize a metal rather than a plastic screw 2420 in view of the mechanical stresses involved. It is understood that the present invention is not limited to the use of a screw 2420 and pin 2410 but rather other fastening means may also be used. As noted previously, both the end caps 100 and spacers 110 can be fabricated of an insulative material, such as a plastic, covered with a conductive material to provide electromagnetic shielding or can be fabricated entirely of a conductive material, such as a metal. FIG. 25 is an exploded view of backbone 150 and an end cap 199 and FIG. 26 is a view of a backbone 150 and an end cap 199 assembled together. Referring to FIGS. 25 and 26 , the bosses 2300 of the backbone 150 are disposed within corresponding apertures 2402 in the end caps 100 forming a rigid structure. The use of bosses 2300 and apertures 2402 is for exemplary purposes and the present invention is not limited thereto. That is, other fastening means can be used to mechanically connect the backbone 150 to the end caps 100 . Furthermore, as shown in FIG. 27 , a combination of fingers 440 and mating slots are used to mechanically connect the spacers 110 to the backbone 150 . The illustrated combination is for exemplary purposes and the present invention is not limited thereto. In a similar fashion, as discussed above, the fingers 435 , 437 , 835 , 837 of the spacers 110 are arranged to mate with corresponding slots in the interposer 180 . The illustrated combination of fingers and slots is for exemplary purposes and the present invention is not limited thereto. Referring back to FIG. 1 , FIG. 1 shows that connector 100 may also include a two mounting clips 190 a and 190 b and a shield 160 . Mounting clips 190 and shield 160 are combined with the above described parts of the connector 100 to form a composite arrangement. The mounting clip 190 and shield 160 may be electrically conductive so as to electromagnetically shield the signal carrying elements of connector 100 . The mounting clip 190 and shield 160 will be discussed in detail below. FIG. 28 illustrates an embodiment of mounting clip 190 b . Mounting clip 190 b , according to the embodiment shown, includes: (a) pins 2860 arranged to mate with a hole in a circuit board (e.g., board 2190 or 2180 ) and (b) slots 2870 arranged to receive the tongues and 2430 of the end caps 100 . Pins 2860 function to connect clip 190 b to a circuit board by mating with the circuit board holes mentioned above. Pins 2860 may be electrically conducting and may electrically and physically connect to a ground plane of the circuit board to which it is connected. FIG. 29 is an exploded view of clip 190 b and end cap 199 and FIG. 30 is a view of clip 190 b having an end cap 199 attached thereto. As shown in FIG. 30 , tongue 2430 of end cap 199 is arranged to mate with a corresponding slot 2870 in clip 190 b . As with the other illustrated fastening means, the present invention is not limited to the use of a tongue and corresponding slot. Referring now to FIG. 31 , FIG. 31 illustrates an embodiment of shield 160 . Shield 160 , according to the embodiment shown, includes hooks 3100 arranged to fit in slots in an interposer 180 . FIG. 32 is an exploded view of shield 160 and an interposer 180 . FIG. 33 is a view of shield 160 being connected to an interposer 180 . FIG. 33 illustrates how the hooks 3100 of shield 160 snap into slots in interposer 180 , thereby mechanically connecting the two. FIG. 34 is a view of an assembled connector with an interposer 180 and clip 190 a omitted. FIGS. 35 and 36 are different views of an almost fully assembled connector 100 according to one embodiment. When fully assembled, each aperture in each interposer holds a cell 1570 . Referring to FIG. 35 , FIG. 35 shows end caps 199 a and 199 b , shield 160 , interposer 180 a and clip 190 b. Referring to FIG. 36 , FIG. 36 shows end caps 199 a and 199 b , interposers 180 a and 180 b , and clips 190 a and 190 b . The clip 190 a may be attached to the overall assembly by any usual fastening means and can include pins or other fastening means to attach the assembled connector 100 to a daughtercard, for example. The additional interposer 180 b and additional clip 190 a may be identical to the interposer 180 a and end plate 190 b or can be different (or not present at all), depending upon the application of the interconnection system assembly. While the two interposers 180 have been illustrated as being perpendicular to each other, the present invention is not limited thereto. That is, for some applications, the planes of the two interposers 180 can be at a 45-degree angle or other angle, for example. Thus, connector 100 need not be a “right-angle” connector. As can be seen from FIGS. 34–36 , the entire interconnection system assembly attaches together to form a rigid structure in which the electrical conductors on the printed circuit boards 120 may be entirely electromagnetically shielded. While various embodiments/variations of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

The present invention provides a high-speed electrical interconnection system designed to overcome the drawbacks of conventional interconnection systems. That is, the present invention provides an electrical connector capable of handling high-speed signals effectively.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a divisional of U.S. patent application Ser. No. 09/661,657, filed Sep. 14, 2000, now U.S. Pat. No. 6,498,409, the contents of which are incorporated herein by reference. This application claims the benefit of U.S. Provisional Application 60/154,279 filed Sep. 16, 1999, the contents of which are incorporated herein by reference. TECHNICAL FIELD The invention relates to a tachometer apparatus and methodology for determining the velocity of a motor as applied to a vehicle steering system. BACKGROUND OF THE INVENTION Speed sensors, or detectors of various types are well known in the art. In recent years the application of speed detection to motor control functions has stimulated demands on the sophistication of those sensors. Rotational speed sensors are commonly configured in the same manner as an electric machine, for example, a coil is placed in proximity to rotating magnets whereby the magnetic field induces a voltage on the passing coil in accordance with Faraday's Law. The rotating permanent magnets induce a voltage on the coil and ultimately a voltage whose frequency and magnitude are proportional to the rotational speed of the passing magnets. Many of the tachometers that are currently available in the art exhibit a trade off between capabilities and cost. Those with sufficient resolution and accuracy are often very expensive and perhaps cost prohibitive for mass production applications. Those that are inexpensive enough to be considered for such applications are commonly inaccurate or provide insufficient resolution or bandwidth for the application. Thus, there is a need, in the art for a low cost robust tachometer that provides sufficient accuracy and resolution for motor control applications and yet is inexpensive enough to be cost effective in mass production. SUMMARY OF THE INVENTION The above-identified drawbacks of the prior art are alleviated by the method described in the invention. A method and apparatus for determining the velocity of a rotating device is described herein. The apparatus includes a set of sense magnets affixed to a rotating shaft of a rotating device and a circuit assembly, which interact to form an air core electric machine. The circuit assembly includes a circuit interconnection having a plurality of sense coils and sensors affixed thereto. The circuit assembly is adapted to be in proximity to the set of sense magnets on the rotating part. A controller is coupled to the circuit assembly, where the controller is adapted to execute an adaptive algorithm that determines the velocity of the rotating device. The algorithm is a method of combining a derived velocity with a velocity from the tachometer. The algorithm includes a plurality of functions including: receiving a position signal related to the rotational position of the shaft; determining a derived velocity from the position signal; generating a plurality of tachometer velocity signals; determining a compensated velocity in response to the plurality tachometer velocity signals; and blending the compensated velocity with derived velocity to generate a blended velocity output. BRIEF DESCRIPTION OF THE DRAWINGS Referring now to the drawings wherein like elements are numbered alike in the several FIGURES: FIG. 1 depicts the cross-section of the fixed and rotating parts of a tachometer; FIG. 2 depicts the sense magnet end-view illustrating the low and high-resolution poles; FIG. 3 depicts a partial view of a tachometer coil arrangement in the circuit interconnection; FIG. 4 depict the expected output waveform from the low-resolution tachometer coils; FIG. 5 depicts a partial view of an alternative embodiment of the tachometer coil arrangement in the circuit interconnection board; FIG. 6 depict the expected output waveform from the high-resolution position sensor; FIG. 7 depicts a top-level functional block diagram of a method for determination of the rotational speed; FIG. 8 depicts the Speed Estimation process; FIG. 9 depicts the Offset Compensation process; FIG. 10 depicts the Get Phase process; FIG. 11 depicts the Blend process; FIG. 12 depicts the AlignToPolled process; and FIG. 13 depicts the Gain process. DETAILED DESCRIPTION OF THE INVENTION The present invention may be utilized in various types of motors and other rotational devices such as, for example, motors employed in a vehicle steering system. A preferred embodiment of the invention, by way of illustration is described herein as it may be applied to a motor tachometer in an electronic steering system. While a preferred embodiment is shown and described, it will be appreciated by those skilled in the art that the invention is not limited to the motor speed and rotation but also to any device where rotational motion and velocity are to be detected. A preferred embodiment of the invention provides a structure and method by which the rotational position and velocity of a motor are determined. Referring to FIG. 1, the invention employs a tachometer structure 10 comprised of rotational part 20 and a fixed circuit assembly 30 . Where the rotational part, 20 includes a rotating shaft 22 and sense magnet 24 . The rotating shaft 22 is connected to, or an element of the device, (not shown) whose rotational speed is to be determined. Referring to FIG. 2, an axial (end) view of the sense magnet 24 is depicted. The sense magnet 24 is attached to the rotating shaft 22 and arranged in two concentric, annular configurations, a first of smaller radius surrounded by the second of larger radius. The concentric, annular configurations may be coplanar. The low-resolution magnet 26 comprising the inner annulus of sense magnet 24 is constructed as a six-pole permanent magnet. While the preferred embodiment utilizes the stated configuration, other configurations are reasonable. The magnet structure need only be sufficient to allow adequate detection in light of the sensing elements utilized, processing employed, and operational constraints. The high-resolution magnet 28 comprising the outer annulus of sense magnet 24 is configured as a 72-pole permanent magnet 28 . Again, the magnet structure need only be sufficient to allow adequate detection in light of the sensing elements, processing employed, and operational constraints. Each of the magnets 26 and 28 is comprised of alternating north and south poles equally distributed around each respective annulus. One skilled in the art would appreciate that the magnets when rotated generate an alternating magnetic field which when passed in proximity to a conductor (coil) induce a voltage on the conductor. Further, using well-understood principles the magnitude of the voltage induced is proportional to the velocity of the passing magnetic field, the spacing and orientation of the coil from the magnets. FIGS. 1 and 3 depict the circuit assembly 30 . The circuit assembly 30 includes; a plurality of tachometer coils 40 , low-resolution Hall sensor set 34 , and high-resolution position sensor 36 . The circuit assembly 30 is placed parallel to and in close proximity to the axial end of the rotating sense magnet 24 . A circuit interconnection 38 provides electrical interconnection of the circuit assembly 30 components and may be characterized by various technologies such as hand wiring, a printed card, flexible circuit, lead frame, ceramic substrate, or other circuit connection fabrication or methodology. A preferred embodiment for the circuit assembly 30 comprises the abovementioned elements affixed to a printed circuit board circuit interconnection 38 of multiple layers. Referring to FIGS. 1 and 3, the tachometer coils 40 are located on the circuit assembly 30 in such an orientation as to be concentric with the sense magnet 24 in close proximity to the inner annulus low resolution poles 26 . In a preferred embodiment of the invention, the conductive tachometer coils 40 are an integral part of the circuit interconnection 38 . The tachometer coils 40 include two or more spiraling conductor coils 42 - 48 concentrically wound in a serpentine fashion such that each conductor comprises a twelve turn winding on each of two layers. Coil A is comprised of windings 42 and 48 and coil B is comprised of windings 46 and 44 . Each of the windings is configured such that it spirals inward toward the center on one layer and outward from the center on the second layer. Thereby, the effects of the windings' physical construction variances on the induced voltages are minimized. Further, the tachometers coils 40 are physically arranged such that each has an equivalent effective depth on the circuit assembly 30 . That is, the windings are stacked within the circuit assembly 30 such that the average axial distance from the magnets is maintained constant. For example, the first layer of coil A, winding 42 could be the most distant from the magnets, and the second layer of coil A, winding 48 the closest to the magnets, while the two layers of coil B 46 and 44 could be sandwiched between the two layered windings of coil A. The exact configuration of the coil and winding arrangement stated is illustrative only, many configurations are possible and within the scope of the invention. The key operative function is to minimize the effects of multiple winding effective distances (gaps) on the induced voltages. While two twelve turn windings are described, the coil configuration need only be sufficient to allow adequate detection in light of the magnetic field strength, processing employed, physical and operational constraints. FIG. 3 depicts a partial view of a preferred embodiment. Three turns of the first layer of coil A, winding 42 are shown. Each winding is comprised of six active 50 and six inactive 52 segments per turn. The active segments 50 are oriented approximately on radials from the center of the spiral while the inactive segments 52 are orientated as arcs of constant radius. The active segments 50 are strategically positioned equidistant about the circumference of the spiral and directly cutting the flux lines of the field generated by the low resolution magnet 26 . The inactive segments 52 are positioned at equal radial distances and are strategically placed to be outside the magnetic flux lines from the low resolution magnet 26 . One skilled in the art will appreciate that the winding is uniquely configured as described to provide maximum voltage generation with each passing pole of the low-resolution magnet 26 in the active segments 50 and minimal or no voltage generation with each passing pole of the low resolution magnet 26 in the inactive segments 52 . This results in predictable voltage outputs on the tachometer coils 40 for each rotation of the low-resolution magnet 26 . A preferred embodiment employs two coils, on two layers each with 144 active and 144 inactive segments. However, it will be understood that only the quantity of active segments 50 not the inactive segments 52 is relevant. Any number of inactive segments 52 is feasible, only dictated by the physical constraints of interconnecting the active segments 50 . Additionally, the tachometer coils 40 are comprised of two (or more) complete spiral serpentine windings 42 - 48 , 46 - 44 . The windings 42 - 48 and 46 - 44 may be oriented relative to one another in such a way that the voltages generated by the two coils would possess differing phase relationships. Further, that the orientation may be configured in such a way as to cause the generated voltages to be in quadrature. In a preferred embodiment where the low-resolution poles are comprised of six magnets of sixty degree segments, the two coils are rotated concentrically relative to one another by thirty degrees. This rotation results in a phase difference of 90 degrees between the two generated voltages generated on each coil. In an exemplary embodiment, the two generated voltages are ideally configured such that the voltage amplitude is discernable for all positions and velocities. In an exemplary embodiment, the two generated voltages are trapezoidal. FIGS. 4 and 6 depicts the output voltage generated on the two coils as a function of rotation angle of the rotating shaft 22 for a given speed. In another embodiment of the invention, the windings may be individually serpentine but not necessarily concentric. Again, the coil configuration need only be sufficient to allow adequate detection in light of the magnetic field strength, processing employed, physical and operational constraints. One skilled in the art would recognize that the coil could be comprised of many other configurations of windings. FIG. 5 depicts one such a possible embodiment of the invention. Referring again to FIG. 1, in a preferred embodiment, the Hall sensor set 34 is located on the circuit assembly 30 in an orientation concentric with the tachometer coils 40 and concentric with the rotating part 20 . Additionally, the Hall sensor set is placed at the same radius as the active segments 50 of the tachometer coils 40 to be directly in line axially with the low-resolution poles 26 of the sense magnet 24 . The Hall sensor set 34 is comprised of multiple sensors equidistantly separated along an arc length where two such sensors are spaced equidistant from the sensor between them. In a preferred embodiment, the Hall sensor set 34 is comprised of three Hall effect sensors, 34 a , 34 b , and 34 c , separated by 40 degrees and oriented along the described circumference relative to a predetermined reference position so that absolute rotational position of the rotating part 20 may be determined. Further, the Hall sensor set 34 is positioned to insure that the active segments 50 of the tachometer coils 40 do not interfere with any of the Hall sensors 34 a , 34 b , and 34 c or vice versa. It is also noteworthy to consider that in FIG. 1, the Hall sensor set 34 is depicted on the distant side of the circuit assembly 30 relative to the low-resolution magnet 26 . This configuration addresses the trade between placing the Hall sensor set 34 or the tachometer coils 40 closest to the low-resolution magnet 26 . In a preferred embodiment, such a configuration is selected because the signals from the Hall sensor set 34 are more readily compensated for the additional displacement when compared to the voltages generated on the tachometer coils 40 . It will be appreciated by those skilled in the art that numerous variations on the described arrangement may be contemplated and within the scope of this invention. The Hall sensor set 34 detects the passing of the low-resolution magnet 26 and provides a signal voltage corresponding to the passing of each pole. This position sensing provides a signal accurately defining the absolute position of the rotational part 20 . Again, in the preferred embodiment, the three signals generated by the Hall sensor set 34 with the six-pole low-resolution magnet facilitate processing by ensuring that certain states of the three signals are never possible. One skilled in the art will appreciate that such a configuration facilitates error and failure detection and ensures that the trio of signals always represents a deterministic solution for all possible rotational positions. The position sensor 36 is located on the circuit assembly 30 in such an orientation as to be directly in line, axially with the magnets of the outer annulus of the sense magnet 24 , yet outside the effect of the field of the low-resolution magnet 26 . The position sensor 36 detects the passing of the high-resolution magnet 28 and provides a signal voltage corresponding to the passing of each pole. To facilitate detection at all instances and enhance detectability, the position sensor 36 includes two Hall effect sensors in a single package separated by a distance equivalent to one half the width of the poles on the high-resolution magnet 28 . Thus, with such a configuration the position signals generated by the position sensor 36 are in quadrature. One skilled in the art will appreciate that the quadrature signal facilitates processing by ensuring that one of the two signals is always deterministic for all possible positions. Further, such a signal configuration allows secondary processing to assess signal validity. FIG. 6 depicts the output voltage as a function of rotational angle of the position sensor 36 for a given speed. It is noteworthy to point out that the processing of the high-resolution position allows only a relative determination of rotational position. It is however, acting in conjunction with the information provided by the low-resolution position signals from the Hall sensor set 34 that a determination of the absolute position of the rotating part 20 is achieved. Other applications of the low-resolution position sensor are possible. In another embodiment of the invention, the structure described above is constructed in such a fashion that the active segments of the tachometer coils 40 are at a radial proximity to the sense magnets instead of axial. In such an embodiment, the prior description is applicable except the rotational part 20 would include magnets that are coaxial but not coplanar and are oriented such that their magnetic fields radiate in the radial direction rather than the axial direction. Further, the circuit assembly 30 may be formed cylindrically rather than planar and coaxial with the rotational part 20 . Finally, the tachometer coils 40 , Hall sensor set 34 , and position sensor 36 , would again be oriented such that the active segments 50 would be oriented in the axial direction in order to detect the passing magnetic field of the low-resolution magnet 26 . FIG. 7 depicts the top-level block diagram of the processing functions employed on the various signals sensed to determine the rotational speed of a rotating device. The processing defined would be typical of what may be performed in a controller. Such a controller may include, without limitation, a processor, logic, memory, storage, registers, timing, interrupts, and the input/output signal interfaces as required to perform the processing prescribed by the invention. Referring again to FIG. 7, where the blocks 100 - 1000 depict the adaptive algorithm executed by the abovementioned controller in order to generate the tachometer output. The first four blocks 100 , 200 , 400 , 600 perform the “forward” processing of the tachometer coil signals to arrive at the final blended output. While, the last two 800 , 1000 comprise a “feedback” path thereby constructing the adaptive nature of the algorithm. In FIG. 7, the function labeled Speed Estimation 100 generates a digital, derived velocity signal. The process utilizes Motor_Position_HR the high-resolution position sensed by 36 , and a processor clock signal for timing. The process outputs a signal Motor_Vel_Der_ 144 which is proportional to the velocity of the motor over the sample period of the controller. Continuing to Offset Compensation 200 where processing is performed to generate filtered tachometer signals to remove offsets and bias. The process utilizes the two tachometer coil signals HallTachVoltX 1 , HallTachVoltX 2 , the derived velocity Motor_Vel_Der_ 144 and two phase related feedback signals int_Phase 0 and int_Phase 1 as inputs and generates compensated velocity outputs X 1 _Corr and X 2 _Corr. Continuing to Get Phase 400 where processing is performed to ascertain magnitude and phase relationships of the two compensated velocities. Inputs processed include the compensated velocities X 1 _Corr, X 2 _Corr, and the motor position Motor_Position_SPI as derived from the high-resolution position detected by sensor 36 . The process generates two primary outputs, the selected tachometer magnitude tach 13 vel_mag and the selected tachometer phase tach_vel_sign. Moving to the Blend 600 process where predetermined algorithms determine a blended velocity output. The process utilizes the selected tachometer magnitude tach_vel_mag and the selected tachometer phase tach_vel 13 sign to generate two outputs; the blended velocity Blend_Vel_Signed and the velocity sign OutputSign. Considering now the AlignToPolled 800 process wherein the tachometer magnitude tach_vel_mag is time shifted based upon the magnitude of the derived velocity Motor_Vel_Der_ 144 . The selected signal is filtered and supplied as an output as Filtered_Tach. Finally, looking to Gain 1000 where the process generates an error command resultant from the difference between the derived velocity and filtered tachometer under predetermined conditions. The error signal is integrated and utilized as an error command signal for gain adjustment feedback The process utilizes the derived velocity Motor_Vel_Der_ 144 and the Filtered_Tach signal as inputs to generate two outputs int_Phase 0 and int_Phase 1 . These two signals form the gain adjustment feedback that is then utilized as an input in the abovementioned Offset Compensation 200 . Referring now to FIG. 7 and FIG. 8 for a more detailed description of the functional operation of each of the processes identified above. FIG. 8 depicts the functions that comprise the Speed Estimation 100 process block. This process is a method of extracting a digital, derived velocity based on the per sample period of change of the position signal. The process utilizes as an input Motor_Position_HR the high-resolution position detected by sensor 36 , and outputs a signal Motor_Vel_Der _ 144 , which is proportional to the derived velocity of the motor. The process computes the velocity by employing two main functions. The first is the Deltact calculation process 102 where a position change DELTA_POSITION is computed by subtracting the high-resolution position Motor_Position_HR delayed by one sample from the current high-resolution position Motor_Position_HR. That is, subtracting the last position from the current position. The position difference is then divided by the difference in time between the two samples. An equation illustrating the computation is as follows: Deltact = P 0 - P - 1 T 0 - T - 1 A preferred embodiment of the above equation evaluates a changing measured position over a fixed interval of time to perform the computation. It will be appreciated by those skilled in the art, that the computation may be performed with several variations. An alternative embodiment, evaluates a changing measured time interval for a fixed position change to perform the computation. Further, in yet another embodiment, both the interval of time and interval position could be measured and compared with neither of the parameters occurring at a fixed interval. A filter 104 further processes the calculated Deltact value. Where the filtering characteristics are selected and determined such that the filter yields a response sufficiently representative of the true velocity of the motor without adding excessive delay. One skilled in the art will appreciate and understand that there can be numerous combinations, configurations, and topologies of filters that can satisfy such requirements. A preferred embodiment employed a four-state moving average filter. The signal is labeled Motor_Vel_Der, which is then scaled at gain 106 and output from the process as the value labeled Motor_Vel_Der_ 144 . This parameter is utilized throughout the invention as a highly accurate representation of the velocity. FIG. 9 depicts the functions that comprise the Offset Compensation process 200 . The process extracts the respective offset and bias from each of the two tachometer coil signals HallTachVoltX 1 and HallTachVoltX 2 resulting in compensated velocity outputs X 1 _Corr and X 2 _Corr. The extraction is accomplished by an algorithm that under predetermined conditions subtracts from each of the tachometer signals its low frequency spectral components. The algorithm is characterized by scaling 202 ; a selective, adaptive, filter 204 ; and a gain schedule/modulator Apply Gain 210 . Where, the scaling 202 provides gain and signal level shifting resultant from the embodiment with an analog to digital conversion; the adaptive filter 204 comprises dual selective low pass filters 206 and summers 208 enabled only when the tachometer signals' levels are valid; and gain scheduling, which is responsive to feedback signals int_Phase 0 and int_Phase 1 from the Gain process 1000 . The adaptive filter 204 is characterized by conditionally enabled low pass filters 206 , and summers 208 . The low pass filters 206 under established conditions, are activated and deactivated. When activated, the filter's 206 results are the low frequency spectral content of the tachometer signals to a predetermined bandwidth. When deactivated, the filter 206 yields the last known filter value of the low frequency spectral content of the tachometer signals. It is important to consider that the filter 206 is activated when the tachometer signals are valid and deactivated when they are not. In a preferred embodiment, this occurs when the tachometer signals saturate at a high velocity. Various conditions may dictate the validity of the tachometer signals. In a preferred embodiment, within certain hardware constraints, to satisfy low speed resolution and bandwidth requirements, high speed sensing capability with the tachometer signals is purposefully ignored. This results in the tachometer signals saturating under high speed operating conditions. As such, it is desirable to deactivate the filters 206 under such a condition to avoid filtering erroneous information. A summer 208 subtracts the low pass filter 206 outputs to the original tachometer signals thereby yielding compensated tachometer signals with the steady state components eliminated. The filter 206 characteristics are established to ensure that the filter response when added to the original signals sufficiently attenuates the offsets and biases in the tachometer signals. One skilled in the art will appreciate that there can be numerous combinations, configurations, and topologies of filters that can satisfy such requirements. A preferred embodiment employs an integrating loop low pass filter. The gain scheduling function Apply Gain 210 is responsive to feedback signals int_Phase 0 and int_Phase 1 from the Gain process 1000 (discussed below). The Apply Gain 210 process scales the compensated velocity outputs X 1 _Corr and X 2 _Corr as a function of the feedback signals int_Phase 0 and int_Phase 1 . Thereby providing a feedback controlled correction of the velocity signal for accuracy and speed correction. FIG. 10 depicts the internal process of Get Phase 400 where processing is performed to ascertain magnitude and phase relationships of the two compensated velocities. Inputs processed include the offset compensated velocities X 1 _Corr, X 2 _Corr, the motor position Motor 13 Position_ SPI, and a calibration adjustment signal TachOffset. The motor position signal Motor_Position_SPI derived from the high-resolution position as detected by sensor 36 and indexed to the absolute position as described earlier. The TachOffset input allows for an initial fabrication based adjustment to address differences or variations in the orientation of the tachometer coils 40 (FIGS. 1 and 3) and the low-resolution Hall sensor set 34 (FIG. 1 ). The process generates two primary outputs, the selected tachometer magnitude tach_vel_mag and the selected tachometer phase tach_vel_sign. The process independently determines which tachometer signal magnitude and phase to select by making a comparison with the high-resolution position Motor_Position_SPI. The process determines the magnitude of the two velocities X 1 _Corr and X 2 _Corr at 402 . Then at comparator 404 determines the larger of the two and then generates a discrete, Phase_Sel, indicative of which velocity has the larger magnitude. The larger magnitude velocity is selected because by the nature of the two trapezoidal signals, one is guaranteed to be at its maximum. The discrete Phase_Sel controls a switch 406 , which in turn passes the selected tachometer velocity magnitude termed tach_vel_mag. The discrete Phase_Sel is also utilized in later processes. A second and separate comparison at 408 with the high-resolution position Motor_Position_SPI extracts the respective sign associated with the velocity. Again, it will be understood that those skilled in the art may conceive of variations and modifications to the preferred embodiment shown above. For example, one skilled in the art would recognize that the phase information could have also been acquired merely by utilizing the position information alone. Such an approach however, suffers in that it would be highly sensitive to the precise positioning and timing on the trapezoidal waveforms to insure an accurate measurement. Such a restriction is avoided in the preferred embodiment, thereby simplifying the processing necessary. FIG. 11 depicts the Blend 600 process function where predetermined algorithms determine a blended velocity output. The process utilizes the selected tachometer magnitude tach_vel_mag, the derived velocity Motor_Vel Der_ 144 and the selected tachometer phase tach_vel_sign to generate two outputs; the blended velocity Blend_Vel_Signed and the velocity sign OutputSign. A blended velocity solution is utilized to avoid the potential undesirable effects of transients resultant from rapid transitions between the derived velocity and the tachometer-measured velocity. The process selects based upon the magnitude of the derived velocity Motor_Vel_Der_ 144 a level of scheduling at gain scheduler 602 of the derived velocity with the compensated, measured, and selected velocity, tach_vel_mag. Summer 604 adds the scheduled velocities, which are then multiplied at 606 by the appropriate sign as determined from the tachometer phase tach_vel_sign to generate the blended composite signal. The blended composite signal comprises a combination of the tachometer measured velocity and the derived velocity yet without the negative effects of saturation or excessive time delays. FIG. 12 depicts the AlignToPolled 800 process, which time shifts (delays) the tachometer magnitude tach_vel_mag to facilitate a coherent comparison with the derived velocity Motor_Vel_Der_ 144 . The filtering is only employed when the tachometer magnitude tach_vel_mag is within a valid range as determined in processes 802 and 804 . The valid range is determined based upon the magnitude of the derived velocity Motor_Vel_Der_ 144 . As stated earlier, the validity of the tachometer signals is related to high speed saturation, while for the derived velocity it is a function of filtering latency at very low speed. A selection switch 804 responsive to the magnitude of the derived velocity Motor_Vel_Der_ 144 controls the application of the tach_vel_mag signal to the filter. The multiplication at 808 applies the appropriate sign to the tach_vel_mag signal. A filter 806 is employed to facilitate generation of the time delay. The appropriate time delay is determined based upon the total time delay that the derived velocity signals experience relative to the tachometer signals. The time shift accounts for the various signal and filtering effects on the analog signals and the larger time delay associated with filtering the derived velocity signal. As stated earlier, the derived velocity signal experiences a significant filtering lag, especially at lower speeds. Introducing this shift yields a result that makes the tachometer signals readily comparable to the derived velocity. The selected signal is delivered as an output as Filtered_Tach. In a preferred embodiment, the resultant filter 806 is a four state moving average filter similar to the filter 104 (FIG. 8) implemented in the Speed Estimation process. One skilled in the art will recognize that there can be numerous combinations, configurations, and topologies of filters that can satisfy such requirements. Referring now to FIG. 13, the Gain 1000 process block where an error command is generated and subsequently utilized as a gain correction in the adaptive algorithm of the present invention. In a preferred embodiment, the error command is resultant from a ratiometric comparison 1002 of the magnitudes of the derived velocity to the filtered tachometer velocity. The ratio is then utilized to generate an error signal at summer 1004 . Under predetermined conditions, controlled by state controller 1006 , error modulator 1008 enables or disables the error signal. That is, modulator 1008 acts as a gate whereby the error signal is either passed or not. The state controller 1006 allows the error signal to be passed only when the error signal is valid. For example, when both the filtered tachometer velocity and the derived velocity are within a valid range. In a preferred embodiment, the error signal is passed when the magnitude of the Motor_Vel_Der_ 144 signal is between 16 and 66.4 radians per second. However, the modulator is disabled and the error signal does not pass if the magnitude of the Motor_Vel_Der_ 144 signal exceeds 72 or is less than 10.4 radians per second. Under these later conditions, the ratiometric comparison of the two velocities and the generation of an error signal is not valid. At very small velocities, the signal Motor_Vel_Der_ 144 exhibits excessive delay, while at larger velocities, that is in excess of 72 radians per second, the tachometer signals are saturated. The error signal when enabled is passed to the error integrator 1010 , is integrated, and is utilized as an error command signal for gain adjustment feedback. The error integrators 1010 selectively integrate the error passed by the modulator 1008 . The selection of which integrator to pass the error signal to is controlled by the time shifted Phase_Sel signal at delay 1012 . These two correction signals int_Phase 0 and int_Phase 1 form the gain adjustment feedback that is then utilized as an input in the abovementioned Offset Compensation 200 process. The disclosed invention may be embodied in the form of computer-implemented processes and apparatuses for practicing those processes. The present invention can also be embodied in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. The present invention can also be embodied in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits. It will be understood that those skilled in the art may conceive variations and modifications to the preferred embodiment shown herein within the scope and intent of the claims. While the present invention has been described as carried out in a specific embodiment thereof, it is not intended to be limited thereby but is intended to cover the invention broadly within the scope and spirit of the claims.

A method and system for determining the velocity of a rotating device is described herein. The system includes an apparatus with a set of sense magnets affixed to a rotating shaft of the rotating device and a circuit assembly. The circuit assembly includes a circuit interconnection having a plurality of sense coils and sensors affixed thereto. The circuit assembly is adapted be in proximity to the set of sense magnets on the rotating part. A controller is coupled to the circuit assembly, where the controller executes an adaptive algorithm that determines the velocity of the rotating device. The algorithm is a method of combining a derived velocity with a velocity from the tachometer. The algorithm includes a plurality of functions including: receiving a position signal related to the rotational position of the shaft; determining a derived velocity from the position signal; generating a plurality of tachometer velocity signals; determining a compensated velocity in response to the plurality tachometer velocity signals; and blending the compensated velocity with derived velocity to generate a blended velocity output.

FIELD OF THE INVENTION [0001] The present invention relates to novel intermediates which are useful in the synthesis of calcipotriol {(5Z, 7E, 22E, 24S)-24-cyclopropyl-9,10-secochola-5,7,10(19),22-tetraene-1α-3β-24-triol} and methods for the preparation thereof. The present invention relates further to the use of intermediates produced with said methods for making calcipotriol or calcipotriol monohydrate. BACKGROUND OF THE INVENTION [0002] Calcipotriol or calcipotriene (structure I) [CAS 112965-21-6] shows a strong activity in inhibiting undesirable proliferation of epidermal keratinocytes [F. A. C. M. Castelijins, M. J. Gerritsen, I. M. J. J. van Vlijmen-Willems, P. J. van Erp, P. C. M. van de Kerkhof; Acta Derm. Venereol. 79, 11, 1999]. The efficacy of calcipotriol (Ia) and calcipotriol monohydrate (Ib) in the treatment of psoriasis was shown in a number of clinical trials [D. M. Ashcroft et al.; Brit. Med. J. 320, 963-67, 2000] and calcipotriol is currently used in several commercial drug formulations. [0003] A key step in the synthesis of calcipotriol or intermediates useful for the synthesis of calcipotriol is the attachment of the cyclopropyl-enone side chain to the CD-ring of suitable precursors, which has been described with a Wittig reagent IV. [0004] For example, in an industrial synthesis of calcipotriol, the cyclopropyl containing phosphorane side chain IV is reacted with the aldehyde IIIa in a Wittig reaction to give the enone Va, wherein R 1 and R 2 are tert-butyldimethylsilyl (see e.g. WO 87/00834 or M. J. Calverley; Tetrahedron, 43 (20), 4609-19, 1987). Calcipotriol is then obtained from the key intermediate Va by reduction to the C-24 alcohol followed by photoisomerisation and the removal of the silyl protecting groups. [0005] The Wittig processes using the phosphorane IV have a number of disadvantages, especially on a large scale: a) During the C═C-bond forming reaction triphenylphosphine oxide is formed as a side product which is difficult to remove from the reaction mixture. The formation of triphenylphosphine oxide currently adds an additional chromatographic step to the process outlined above. b) The Wittig reaction furthermore necessitates reaction temperatures above 95° C. due to the low reactivity of the phosphorane IV. Lower reaction temperatures would be advantageous in an industrial process. [0006] It is an object of this invention to provide an alternative process which may overcome one or more of the various problems and disadvantages described above. The present invention thus provides a novel process which can be run at lower temperature and which avoids the tedious chromatographic removal of triphenylphosphine oxide to produce intermediates useful for the synthesis of calcipotriol, such as the enone of general structure Va. SUMMARY OF THE INVENTION [0007] It was surprisingly found that a compound of general structure IIa, wherein the carbon marked with an asterisk is either connected by a single bond to a carbon atom of a vitamin D analogue fragment at C-17, or to a fragment of a precursor for the synthesis of a vitamin D analogue at a C-17 analogous position, can be reacted with a phosphonate of general structure VII, wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy, in the presence of a base, to give a compound of general structure of general structure II, wherein the carbon marked with an asterisk is either connected by a single bond to a carbon atom of a vitamin D analogue fragment at C-17, or to a fragment of a precursor for the synthesis of a vitamin D analogue at a C-17 analogous position. [0008] Accordingly, a compound of general structure IIIa, IIIb, VIa, VIb, XIIIa, XIIIb, XVa, or XVb, or IXX, wherein R 1 and R 2 are the same or different and represent hydrogen or a hydroxy protecting group, and wherein R 5 represents hydrogen or a hydroxy protecting group, can be reacted with a phosphonate of general structure VII, wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy, in the presence of a base, to give a compound of general structure Va, Vb, VIIIa, VIIIb, XIVa, XIVb, XVIa, XVIb, or XX respectively, wherein R 1 , R 2 , and R 5 are as defined above. [0009] This process, also called Wadsworth-Emmons, Wittig-Horner, or Horner-Emmons-Wadsworth reaction, has several advantages over the use of the phosphorane reagent IV: a) The reagent of general structure VII is more reactive than the corresponding phosphorane allowing the usage of mild reaction conditions such as low temperature, typically below 35° C. b) The phosphorus product of the reaction is a phosphate ester, and hence soluble in water, unlike triphenylphosphine oxide, which makes it easy to separate it from the enones Va, Vb, VIIIa, VIIIb, XIVa, XIVb, XVIa, XVIb, or XX. c) The Wittig-Horner reaction is more trans-selective resulting in a better yield and in improved purity of the desired products Va, Vb, VIIIa, VIIIb, XIVa, XIVb, XVIa, XVIb, or XX. [0010] In a first aspect, this invention relates to a method of reacting a compound of general structure IIIa, IIIb, VIa, VIb, XIIIa, XIIIb, XVa, XVb, or IXX as above with a phosphonate of general structure VII to give a compound of general structure Va, Vb, VIIIa, VIIIb, XIVa, XIVb, XVIa, XVIb, or XX as above. [0011] In another aspect, this invention relates to a compound of general structure Vb, wherein R 1 and R 2 are the same or different and each represent a hydroxy protecting group, or R 1 represents hydrogen and R 2 represents a hydroxy protecting group, or R 2 represents hydrogen and R 1 represents a hydroxy protecting group. [0012] In yet another aspect, this invention relates to 20(R),1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(Z),7(E),10(19)-triene. [0013] In yet another aspect, this invention relates to a compound of general structure XIVa, wherein R 1 represents hydrogen or a hydroxy protecting group, with the proviso that R 1 cannot be tert-butyldimethylsilyl. [0014] In yet another aspect, this invention relates to a compound of general structure XIVb, wherein R 1 represents hydrogen or a hydroxy protecting group. [0015] In yet another aspect, this invention relates to a compound of general structure VII, wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy, provided that that the compound is not (2-cyclopropyl-2-oxoethyl)-phosphonic acid diethyl ester. [0016] In yet another aspect, this invention relates to a compound of general structure IIIa, wherein R 1 and R 2 are the same or different and represent hydrogen or a hydroxy protecting group, with the provisos that R 1 and R 2 cannot both be tert-butyldimethylsilyl, tert-butyidiphenylsilyl, or triisopropylsilyl; with the further proviso that when R 2 is tert-butyldimethylsilyl, R 1 cannot be tert-butyldiphenylsilyl. [0017] In yet another aspect, this invention relates to a compound of general structure IIIb, wherein R 1 represents a hydroxy protecting group, and R 2 represents hydrogen or a hydroxy protecting group; or R 1 represents a hydrogen or a hydroxy protecting group, and R 2 represents a hydroxy protecting group, except acetyl; with the proviso that R 1 and R 2 cannot both be tert-butyldimethylsilyl. [0018] In yet another aspect, this invention relates to a compound of general structure VIa or VIb, wherein R 1 and R 2 are the same or different and represent hydrogen or a hydroxy protecting group, with the proviso that R 1 and R 2 cannot both be tert-butyldimethylsilyl. [0019] In yet another aspect, this invention relates to a compound of general structure XIIIa, wherein R 1 represents hydrogen or a hydroxy protecting group, except tert-butyldimethylsilyl. [0020] In yet another aspect, this invention relates to a compound of general structure XIIIb, wherein R 1 represents a hydroxy protecting group, except tert-butyldimethylsilyl. [0021] In yet another aspect, this invention relates to a compound of general structure XVa or XVb, wherein R 1 represents a hydroxy protecting group, except tert-butyldimethylsilyl, triisopropylsilyl, acetyl, or triethylsilyl. [0022] In yet another aspect, this invention relates to a compound of general structure XX, wherein R 5 represents hydrogen or a hydroxy protecting group. [0023] In yet another aspect, this invention relates to a compound of general structure XXIa, wherein R 5 and R 6 are the same or different and represent hydrogen or a hydroxy protecting group, with the provisos that when R 5 is hydrogen R 6 is not tert-butyldimethylsilyl, and when R 5 is benzoate, R 6 is not tert-butyldimethylsilyl or hydrogen. [0024] In yet another aspect, this invention relates to a compound of general structure XXII, wherein R 6 represents hydrogen or a hydroxy protecting group, except tert-butyldimethylsilyl. [0025] In yet another aspect, this invention relates to a compound of general structure XXIIIb, wherein R 1 and R 2 are the same or different and represent hydrogen or a hydroxy protecting group, and wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy. [0026] In yet another aspect, this invention relates to a compound of general structure XVIa or XVIb, wherein R 1 represents hydrogen or a hydroxy protecting group. [0027] In a still further aspect, this invention relates to the use of a compound, such as a compound of general formula Vb, XIVa, XIVb, VII, IIIa, IIIb, VIa, VIb, XIIIa, XIIIb, XVa, XVb, XX, XXIa, XXII, XXIIIB, or Va as defined above, as an intermediate in the manufacture of calcipotriol or calcipotriol monohydrate. [0028] In a further aspect, this invention relates to a method for producing calcipotriol or calcipotriol monohydrate, the method comprising the steps of: [0000] (i) reacting a compound of general structure IIIa, [0000] wherein R 1 and R 2 are the same or different and represent hydrogen or a hydroxy protecting group, [0029] with a phosphonate of general structure VII, wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy, [0000] in the presence of a base, to give a compound of general structure Va, wherein R 1 and R 2 are as defined above; [0030] (ii) reducing the compound of general structure Va with a suitable reducing agent to give a compound of general structure IXa or a mixture of compounds of general structure IXa and IXb, wherein R 1 and R 2 are as defined above; (iii) optionally separating the compound of general structure IXa from the mixture of compounds of general structure IXa and IXb; (iv) photoisomerising the compound of general structure IXa to the compound of general structure Xa, wherein R 1 and R 2 are as defined above; (v) when R 1 and/or R 2 are not hydrogen, removing the hydroxy protecting group(s) R 1 and/or R 2 of the compound of general structure Xa to generate calcipotriol; and (vi) optionally crystallising the calcipotriol from a mixture of an organic solvent and water to give calcipotriol monohydrate. [0031] In a still further aspect, this invention relates to a method for producing calcipotriol or calcipotriol monohydrate, the method comprising the steps of: [0000] (i) reacting a compound of general structure IIIb, [0000] wherein R 1 and R 2 are the same or different and represent hydrogen or a hydroxy protecting group, [0032] with a phosphonate of general structure VII, wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy, [0000] in the presence of a base, to give a compound of general structure Vb, wherein R 1 and R 2 are as defined above; [0033] (ii) reducing the compound of general structure Vb with a suitable reducing agent to give a compound of general structure Xa or a mixture of compounds of general structure Xa and Xb, wherein R 1 and R 2 are as defined above; (iii) optionally separating the compound of general structure Xa from the mixture of compounds of general structure Xa and Xb; (iv) when R 1 and/or R 2 are not hydrogen, removing the hydroxy protecting group(s) R 1 and/or R 2 of the compound of general structure Xa to generate calcipotriol; and (v) optionally crystallising the calcipotriol from a mixture of an organic solvent and water to give calcipotriol monohydrate. [0034] In a still further aspect, this invention relates to a method for producing calcipotriol or calcipotriol monohydrate, the method comprising the steps of: [0000] (i) reacting a compound of general structure VIa and/or VIb, [0000] wherein R 1 and R 2 are the same or different and represent hydrogen or a hydroxy protecting group, [0035] with a phosphonate of general structure VII, wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy, [0000] in the presence of a base, to give a compound of general structure VIIIa and/or VIIIb, wherein R 1 and R 2 are as defined above; [0000] (ii) heating the compounds of general structure VIIIa and/or VIIIb above 60° C. in the presence of a base to give a compound of general structure Va, [0000] wherein R 1 and R 2 are as defined above; [0000] (iii) reducing the compound of general structure Va with a suitable reducing agent to give a compound of general structure IXa or a mixture of compounds of general structure IXa and IXb, [0000] wherein R 1 and R 2 are as defined above; [0000] (iv) optionally separating the compound of general structure IXa from the mixture of compounds of general structure IXa and IXb; [0000] (v) photoisomerising the compound of general structure IXa to the compound of general structure Xa, [0000] wherein R 1 and R 2 are as defined above; [0000] (vi) when R 1 and/or R 2 are not hydrogen, removing the hydroxy protecting group(s) R 1 and/or R 2 of the compound of general structure Xa to generate calcipotriol; and [0000] (vii) optionally crystallising the calcipotriol from a mixture of an organic solvent and water to give calcipotriol monohydrate. [0036] In a still further aspect, this invention relates to a method for producing calcipotriol or calcipotriol monohydrate, the method comprising the steps of: [0000] (i) reacting a compound of general structure VIa and/or VIb, [0000] wherein R 1 and R 2 are the same or different and represent hydrogen or a hydroxy protecting group, [0037] with a phosphonate of general structure VII, wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy, [0000] in the presence of a base, to give a compound of general structure VIIIa and/or VIIIb, wherein R 1 and R 2 are as defined above; [0038] (ii) reducing the compounds of general structure VIIIa and/or VIIIb, with a suitable reducing agent in an inert solvent, to give compounds of general structure XIaa and/or XIba, or a mixture of compounds of general structure XIaa and/or XIba and XIab and/or XIbb, wherein R 1 and R 2 are as defined above; (iii) optionally separating the compounds of general structure XIaa and/or XIba from the reaction mixture; (iv) heating the compounds of general structure XIaa and/or XIba above 60° C. in the presence of a base to give a compound of general structure IXa, wherein R 1 and R 2 are as defined above; (v) optionally separating the compound of general structure IXa from the reaction mixture; (vi) photoisomerising the compound of general structure IXa to the compound of general structure Xa, wherein R 1 and R 2 are as defined above; (vii) when R 1 and/or R 2 are not hydrogen, removing the hydroxy protecting group(s) R 1 and/or R 2 of the compound of general structure Xa to generate calcipotriol; and (viii) optionally crystallising the calcipotriol from a mixture of an organic solvent and water to give calcipotriol monohydrate; wherein steps (vi) and (vii) may be in reversed order. [0039] In a still further aspect, this invention relates to a method for producing calcipotriol or calcipotriol monohydrate, the method comprising the steps of: [0000] (i) reacting a compound of general structure XIIIa, [0000] wherein R 1 represents hydrogen or a hydroxy protecting group, [0040] with a phosphonate of general structure VII, wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy, [0000] in the presence of a base, to give a compound of general structure XIVa, wherein R 1 is as defined above; [0000] (ii) hydroxylating the compound of general structure XIVa with suitable hydroxylating agent to give a compound of general structure Va, [0000] wherein R 1 represents hydrogen or a hydroxy protecting group and R 2 is hydrogen; [0041] (iii) optionally reacting the compound of general structure Va, wherein R 1 represents hydrogen or a hydroxy protecting group and R 2 is hydrogen with a suitable protecting agent to give a compound of general structure Va, wherein R 1 and R 2 are the same or different and represent a hydroxy protecting group; [0000] (iv) reducing the compound of general structure Va with a suitable reducing agent to give a compound of general structure IXa or a mixture of compounds of general structure IXa and IXb, [0000] wherein R 1 and R 2 are as defined above; [0000] (v) optionally separating the compound of general structure IXa from the mixture of compounds of general structure IXa and IXb; [0000] (vi) photoisomerising the compound of general structure IXa to a compound of general structure Xa, [0000] wherein R 1 and R 2 are as defined above; [0000] (vii) when R 1 and/or R 2 are not hydrogen, removing the hydroxy protecting group(s) R 1 and/or R 2 of the compound of general structure Xa to generate calcipotriol; and [0000] (viii) optionally crystallising the calcipotriol from a mixture of an organic solvent and water to give calcipotriol monohydrate. [0042] In a still further aspect, this invention relates to a method for producing calcipotriol or calcipotriol monohydrate, the method comprising the steps of: [0000] (i) reacting a compound of general structure XIIIb, [0000] wherein R 1 represents hydrogen or a hydroxy protecting group, [0043] with a phosphonate of general structure VII, wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy, [0000] in the presence of a base, to give a compound of general structure XIVb, wherein R 1 is as defined above; [0000] (ii) photoisomerising the compound of general structure XIVb to a compound of general structure XIVa, [0000] wherein R 1 is as defined above; [0000] (iii) hydroxylating the compound of general structure XIVa with suitable hydroxylating agent to give a compound of general structure Va, [0000] wherein R 1 represents hydrogen or a hydroxy protecting group and R 2 is hydrogen; [0044] (iv) optionally reacting the compound of general structure Va, wherein R 1 represents hydrogen or a hydroxy protecting group and R 2 is hydrogen with a suitable protecting agent to give a compound of general structure Va, wherein R 1 and R 2 are the same or different and represent a hydroxy protecting group; [0000] (v) reducing the compound of general structure Va with a suitable reducing agent to give a compound of general structure IXa or a mixture of compounds of general structure IXa and IXb, [0000] wherein R 1 and R 2 are as defined above; [0000] (vi) optionally separating the compound of general structure IXa from the mixture of compounds of general structure IXa and IXb; [0000] (vii) photoisomerising the compound of general structure IXa to the compound of general structure Xa, [0000] wherein R 1 and R 2 are as defined above; [0000] (viii) when R 1 and/or R 2 are not hydrogen, removing the hydroxy protecting group(s) R 1 and/or R 2 of the compound of general structure Xa to generate calcipotriol; and [0000] (ix) optionally crystallising the calcipotriol from a mixture of an organic solvent and water to give calcipotriol monohydrate. [0045] In a still further aspect, this invention relates to a method for producing calcipotriol or calcipotriol monohydrate, the method comprising the steps of: [0000] (i) reacting a compound of general structure XVa and/or XVb, [0000] wherein R 1 represents a hydrogen or a hydroxy protecting group, [0046] with a phosphonate of general structure VII, wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy, [0000] in the presence of a base, to give a compound of general structure XVIa and/or XVIb, [0000] wherein R 1 is as defined above; [0000] (ii) heating the compounds of general structure XVIa and/or XVIb above 60° C. in the presence of a base to give a compound of general structure XIVa, [0000] wherein R 1 is as defined above; [0000] (iii) hydroxylating the compound of general structure XIVa with suitable hydroxylating agent to give a compound of general structure Va, [0000] wherein R 1 represents hydrogen or a hydroxy protecting group and R 2 is hydrogen; [0047] (iv) optionally reacting the compound of general structure Va, wherein R 1 represents hydrogen or a hydroxy protecting group and R 2 is hydrogen with a suitable protecting agent to give a compound of general structure Va, wherein R 1 and R 2 are the same or different and represent a hydroxy protecting group; [0000] (v) reducing the compound of general structure Va with a suitable reducing agent to give a compound of general structure IXa or a mixture of compounds of general structure IXa and IXb, [0000] wherein R 1 and R 2 are as defined above; [0000] (vi) optionally separating the compound of general structure IXa from the mixture of compounds of general structure IXa and IXb; [0000] (vii) photoisomerising the compound of general structure IXa to the compound of general structure Xa, [0000] wherein R 1 and R 2 are as defined above; [0000] (viii) when R 1 and/or R 2 are not hydrogen, removing the hydroxy protecting group(s) R 1 and/or R 2 of the compound of general structure Xa to generate calcipotriol; and [0000] (ix) optionally crystallising the calcipotriol from a mixture of an organic solvent and water to give calcipotriol monohydrate. [0048] In a still further aspect, this invention relates to a method for producing calcipotriol or calcipotriol monohydrate, the method comprising the steps of: [0000] (i) reacting a compound of general structure IXX, [0000] wherein R 5 represents hydrogen or a hydroxy protecting group, [0000] with a phosphonate of general structure VII, [0049] wherein R 3 and R 4 are the same or different and represent alkyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl, each being optionally substituted with one or more substituents selected form the group consisting of alkyl, aralkyl, cycloalkyl, cycloalkenyl, haloalkyl, hydroxyalkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, aryl, oxo, alkoxycarbonyl, alkylcarbonyloxy, halogen, alkoxy, carboxy, sulfo or hydroxy, in the presence of a base, [0000] to give a compound of general structure XX, wherein R 5 is as defined above; [0050] (ii) reducing the compound of general structure XX with a suitable reducing agent to give a compound of general structure XXIa or a mixture of compounds of general structure XXIa and XXIb, wherein R 5 is as defined above and R 6 is hydrogen; (iii) optionally separating the compound of general structure XXIa from the mixture of compounds of general structure XXIa and XXIb; (iv) protecting the allylic hydroxy group of the compound of general structure XXIa with a suitable hydroxy protecting reagent to give a compound of general structure XXIa, wherein R 6 is a hydroxy protecting group and R 5 is as defined above; (v) when R 5 is not hydrogen, removing the hydroxy protecting group R 5 of the compound of general structure XXIa to give a compound of general structure XXIa, wherein R 5 is hydrogen; (vi) oxidising the hydroxy group of the compound of general structure XXIa with a suitable oxidising agent to give a compound of general structure XXII, wherein R 6 is as defined above; (vii) coupling of the compound of general structure XXII with a Wittig reagent XXIIIa or a Wittig Horner reagent XXIIIb, wherein R 1 and R 2 represent a hydrogen or a hydroxy protecting group, and wherein R 3 and R 4 are as defined above; in the presence of a base to give a compound of general structure XXIVa, wherein R 1 and R 2 are the same or different and represent hydrogen or a hydroxy protecting group, and wherein R 6 is as defined above; (viii) when R 6 is not hydrogen, removing the hydroxy protecting group R 6 of the compound of general structure XXIVa; (ix) optionally separating the compound of general structure XXIVa; (x) when R 1 and R 2 are not hydrogen, removing the hydroxy protecting group(s) R 1 and R 2 of the compound of general structure XXIVa to generate calcipotriol; and (xi) optionally crystallising the calcipotriol from a mixture of an organic solvent and water to give calcipotriol monohydrate. DETAILED DESCRIPTION OF THE INVENTION Definitions [0051] As used herein, “vitamin D-analogue” means any derivative of vitamin D 2 or D 3 , such as 1α,25-dihydroxyvitamin D 2 or 1α,25-dihydroxyvitamin D 3 , including derivatives wherein one or more of the A, C, or D ring are modified or/and where the side chain attached to C-17 is different from natural vitamin D 2 or D 3 . Examples of vitamin D-analogues can for example be found in [“Vitamin D”, D. Feldman, Ed., Academic Press, San Diego, USA, 1997] and [G.-D. Zhu et al., Chem. Rev. 1995, 95, 1877-1952] and references cited therein, and include hydroxy protected or unprotected calcipotriol, and isomers and derivatives of calcipotriol. [0052] As used herein, “vitamin D-analogue fragment” means a C-17 radical of a vitamin D-analogue as defined above without the side chain usually attached at C-17. Examples of vitamin D-analogue fragments are represented by structures A, B, C, D, E, F, G, H; wherein the C-17 analogous positions in the sense of the present invention are indicated below; and wherein R 1 and R 2 are the same or different and represent hydrogen or a hydroxy protecting group. [0053] As used herein, “a precursor for the synthesis of a vitamin D-analogue” means any molecule useful in the synthesis of a vitamin D derivative as defined above, such as a starting material or intermediate, wherein part of the precursor molecule becomes incorporated into the final vitamin D-analogue. Examples include, but are not limited to steroid ring systems, such as ergosterol, cholesterol, or 7-dehydrocholesterol, or derivatives of the CD-rings of steroids, such as Grundmann's ketone or derivatives of Grundmann's ketone. Examples of precursors for the synthesis of a vitamin D-analogue can for example be found in [G.-D. Zhu et al., Chem. Rev. 1995, 95, 1877-1952] and references cited therein. Examples of specific derivatives of CD-rings of steroids, which are in particular useful are the ring structures M and N illustrated below, wherein PG is hydrogen or a hydrogen protecting group as defined below. [0054] A C-17 analogous position of such a precursor is intended to mean the carbon atom of said precursor, which will correspond to the C-17 carbon atom in the final vitamin D-analogue or calcipotriol. [0055] As used herein, “a fragment of a precursor for the synthesis of a vitamin D-analogue” means a radical of a precursor for the synthesis of a vitamin D-analogue as defined above. For example a fragment of a precursor for the synthesis of a vitamin D-analogue may be a steroid ring system fragment, which may be represented by structure Q or R, wherein the C-17 analogous positions in the sense of the present invention are indicated below. [0056] Other examples of fragments of a precursor for the synthesis of a vitamin D-analogue are fragments of derivatives of the CD-rings of steroids, which may for example be represented by structure O or P, wherein the C-17 analogous positions in the sense of the present invention are indicated and wherein PG is as defined above. [0057] As used herein a “hydroxy protecting group” is any group which forms a derivative that is stable to the projected reactions wherein said hydroxy protecting group can be selectively removed by reagents that do not attack the regenerated hydroxy group. Said derivative can be obtained by selective reaction of a hydroxy protecting agent with a hydroxy group. Silyl derivatives, e.g. trialkylsilyl, such as tert-butyldimethylsilyl, trimethylsilyl, triethylsilyl, diphenylmethylsilyl, triisopropylsilyl, tert-butyldiphenylsilyl, forming silyl ethers are examples of hydroxy protecting groups. Silyl chlorides such as tert-butyldimethylsilyl chloride (TBSCI), trimethylsilylchloride, triethylsilylchloride, diphenylmethylsilylchloride, triisopropylsilylchloride, and tert-butyidiphenylsilylchloride are examples of hydroxy protecting agents. Silyl chlorides are for example reacted with the hydroxy group(s) in the presence of a base, such as imidazole. Hydrogen fluoride, such as aqueous HF in acetonitrile, or tetra n-butylammonium fluoride are examples of reagents which can remove silyl groups. Other hydroxy protecting groups include ethers, such as tetrahydropyranyl (THP) ether, benzyl ether, tert-butyl ether, including alkoxyalkyl ethers (acetals), such as methoxymethyl (MOM) ether, or esters, such as chloroacetate ester, trimethylacetate, acetate or benzoate ester. Non-limiting examples of hydroxy protecting groups and methods of protection and removal, all included in the scope of this application, can for example be found in “Protective Groups in Organic Synthesis”, 3 rd ed., T. W. Greene & P. G. M. Wuts eds., John Wiley 1999 and in “Protecting Groups”, 1 st ed., P. J. Kocienski, G. Thieme 2000, Jarowicki, K., Kocienski, P., J. Chem. Soc., Perkin Trans. 1, 2000, 2495-2527, all of which are hereby incorporated by reference. [0058] As used herein, “alkyl” is intended to mean a linear or branched alkyl group, which may be cyclic or acyclic, having one to twenty carbon atoms, such as 1-12, such as 1-7, such as 1-4 carbon atoms. The term includes the subclasses normal alkyl (n-alkyl), secondary and tertiary alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec.-butyl, tert.-butyl, pentyl, isopentyl, hexyl, isohexyl, and the tert-butyldimethyl group. [0059] The term “halogen” is intended to indicate a substituent from the 7 th main group of the periodic table, preferably fluoro, chloro and bromo. [0060] The term “alkenyl” is intended to indicate a mono-, di-, tri-, tetra- or pentaunsaturated hydrocarbon radical comprising 2-10 carbon atoms, in particular 2-6 carbon atoms, such as 2-4 carbon atoms, e.g. ethenyl, propenyl, butenyl, pentenyl or hexenyl. [0061] The term “alkynyl” is intended to indicate an hydrocarbon radical comprising 1-5 triple C—C bonds and 2-20 carbon atoms, the alkane chain typically comprising 2-10 carbon atoms, in particular 2-6 carbon atoms, such as 2-4 carbon atoms, e.g. ethynyl, propynyl, butynyl, pentynyl or hexynyl. [0062] The term “haloalkyl” is intended to indicate an alkyl group as defined above substituted with one or more halogen atoms as defined above. [0063] The term “hydroxyalkyl” is intended to indicate an alkyl group as defined above substituted with one or more hydroxy groups. [0064] The term “alkoxy” is intended to indicate a radical of the formula —OR′, wherein R′ is alkyl as indicated above, e.g. methoxy, ethoxy, n-propoxy, isopropoxy, butoxy, etc. [0065] The term “alkoxycarbonyl” is intended to indicate a radical of the formula —C(O)—O—R′, wherein R′ is alkyl as indicated above, e.g. methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxycarbonyl, etc. [0066] The term “alkylcarbonyloxy” is intended to indicate a radical of the formula —O—C(O)—R′, wherein R′ is alkyl as indicated above. [0067] The term “cycloalkyl” is intended to indicate a saturated cycloalkane radical comprising 3-20 carbon atoms, preferably 3-10 carbon atoms, in particular 3-8 carbon atoms, such as 3-6 carbon atoms, e.g. cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl. [0068] The term “cycloalkenyl” is intended to indicate mono-, di- tri- or tetraunsaturated non-aromatic cyclic hydrocarbon radicals, comprising 3-20 carbon atoms, typically comprising 3-10 carbon atoms, such as 3-6 carbon atoms, e.g. cyclopropenyl, cyclobutenyl, cyclopentenyl or cyclohexenyl. [0069] The term “aryl” is intended to indicate a radical of aromatic carbocyclic rings comprising 6-20 carbon atoms, such as 6-14 carbon atoms, preferably 6-10 carbon atoms, in particular 5- or 6-membered rings, optionally fused carbocyclic rings with at least one aromatic ring, such as phenyl, naphthyl, indenyl and indanyl. [0070] The term “aralkyl” is intended to indicate an alkyl group as defined above substituted with one or more aryl radicals as defined above. [0071] The term “aralkenyl” is intended to indicate an alkenyl group as defined above substituted with one or more aryl radicals as defined above. [0072] The term “aralkynyl” is intended to indicate an alkynyl group as defined above substituted with one or more aryl radicals as defined above. [0073] As used herein “suitable reducing agent” is intended to mean any agent capable of reducing, preferably enantioselectively or diastereoselectively reducing, the C-24 keto group of a compound of general structure XX, Va, Vb, VIIIa, or VIIb to give preferably a compound of general structure XXIa (R 6 =hydrogen), IXa, Xa, XIaa, or XIba respectively. Examples of reducing agents include, but are not limited to borane reducing agents, metallic hydrides, such as lithium aluminium hydride, sodium borohydride, or AlH 3 , optionally in the presence of lanthanide salts (e.g. LaCl 3 , CeBr 3 , CeCl 3 ), or NaBH 3 (OAc), Zn(BH 4 ) 2 , and Et 3 SiH. Borane reducing agents include borane, borohydrides, and borane complexes with amines or ethers. Non-limiting examples of borane reducing agents e.g. include N,N-diethylaniline-borane, borane-tetrahydrofuran, 9-borabicyclononane (9-BBN), or borane dimethylsulfide. Other reducing agents include, but are not limited to, hydrogen in the presence of a catalyst, such as platinum or ruthenium, sodium in ethanol, isopropyl alcohol and aluminium isopropoxide, and zinc powder in water or alcohol. [0074] When reducing the C-24 keto group of a compound of general structure XX, XVIa, XVIb, VIIIa, or VIIIb, the term “suitable reducing agent” includes chiral reducing agents or chiral ligand-reducing agent complexes, such as the complex of LiAlH 4 and 2,2′-dihydroxy-1,1′binaphthyl. Other examples are hydrogen in the presence of binaphthyl derivatives, such as 2,2′-dihydroxy-1,1′binaphthyl derivatives, e.g. (R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl-ruthenium acetate. [0075] Chiral reducing agents or chiral ligand-reducing agents include reducing agents where a chiral auxiliary is reacted with the reducing agent prior to the reduction in situ to form a chiral reducing agent or the where the chiral auxiliary may for example serve as a chiral ligand in a complex with the reducing agent, i.e. for example to give a chiral reducing agent. The present invention includes the use of such chiral reducing agents or chiral ligand-reducing agent complexes, which were prepared and isolated separately before being used for the reduction. [0076] For example, the chiral auxiliary may react with a borane reducing agent prior to the reduction in situ to form a chiral borane reducing agent or the chiral auxiliary may serve as a chiral ligand in a borane complex. Examples of such chiral borane reducing agents are chiral oxaborolidines or oxazaborolidines, such as chiral oxazaborolidine reagents derived from (1R,2S)-cis-1-amino-2-indanol, (1S,2R)-cis-1-amino-2-indanol, (S)-prolinol, (R)-prolinol or B-(3-pinanyl)-9-borabicyclo[3.3.2]nonane (alpine-borane), or e.g. 5,5-diphenyl-2-methyl-3,4-propano -1,3,2-oxazaborolidine, (S)-2-methyl-CBS-oxazaborolidine, (R)-2-methyl-CBS-oxazaborolidine. The present invention therefore includes the use of such chiral reducing agents, such as chiral borane reducing agents, or chiral ligand-reducing agent complexes, such as chiral ligand-borane complexes, which were prepared and isolated before being used for the reduction. [0077] Another example of a chiral ligand in a complex with the reducing agent is the complex of LiAlH 4 and 2,2′-dihydroxy-1,1′binaphthyl. [0078] The reduction of a compound of general structure XX, XVIa, XVIb, VIIIa, or VIIb may be carried out in the presence of a chiral auxiliary, such as in an inert solvent. Non-limiting examples of chiral auxiliaries include chiral 1,2-amino-alcohols, such as chiral cis-1-amino-2-indanol derivatives, such as (1S,2R)-(−)-cis-1-amino-2-indanol, or cis-1-amino-1,2,3,4-tetrahydronaphthalen-2-ol, such as (1S,2R)-cis-1-amino-1,2,3,4-tetrahydronaphthalen-2-ol. Other examples are binaphthyl derivatives, such as (R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl-ruthenium acetate 2,2′-dihydroxy-1,1′binaphthyl derivatives. Further examples include but are not limited to (R)-(+)-α,α-diphenyl-2-pyrrolidinmethanol, (R)-(+)-2-amino-4-methyl-1,1-diphenyl-1-pentanol, (R)-(−)-2-amino-3-methyl-1,1-diphenyl-1-butanol, (R)-(+)-2-amino-1,1,3-triphenyl-1-propanol, and (1R,2S)-(−)-2-amino-1,2-diphenyl ethanol. [0079] As used herein, “separating a compound” includes the purification and/or isolation of a compound, e.g. to at least 90% purity, such as to at least 95% purity, such as 97% purity, 98% purity, or 99% purity. The term “separating a compound” also includes the meaning of enhancing the concentration of the compound in a mixture of such compounds, optionally comprising solvents, such that the mixture is further enriched with a desired or preferred compound or isomer, such as an epimer, after said separation. Most preferably R 1 and/or R 2 represent alkylsilyl, such as tert-butyldimethylsilyl, and most preferably R 1 and R 2 are the same, and R 6 is hydrogen when compounds of the present invention are separated by chromatography. [0080] As used herein, “inert solvent” means any organic solvent compatible with said suitable reducing agent under the reaction conditions employed, or mixtures of such solvents. The choice of such solvent will depend on the specific reducing agent used. Non-limiting examples of inert solvents include hydrocarbons, such as toluene, and ethers, such as tert-butyl methyl ether or tetrahydrofuran. PREFERRED EMBODIMENTS [0081] In another aspect, this invention relates to 20(R),1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene obtained by a process comprising the method of reacting a compound of general structure IIIa with a phosphonate of general structure VII. [0082] In a further aspect, this invention relates to 20(R),1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(Z),7(E),10(19)-triene obtained by a process comprising the method of reacting a compound of general structure IIIb with a phosphonate of general structure VII. [0083] In a still further aspect, this invention relates to the SO 2 adducts of 20(R),1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene obtained by a process comprising the method of reacting a compound of general structure VIa or VIb with a phosphonate of general structure VII. [0084] In a currently preferred embodiment of the present invention R 1 and/or R 2 represent alkylsilyl, such as tert-butyldimethylsilyl, most preferably R 1 and R 2 are the same. [0085] In another embodiment of the present invention R 1 and/or R 2 represent hydrogen, most preferably R 1 and R 2 are the same. [0086] In a currently preferred embodiment of the present invention R 3 and/or R 4 represent alkyl, such as (C 1 -C 6 )alkyl, such as methyl, ethyl, or 1-propyl, most preferably R 3 and R 4 are the same. [0087] In one embodiment of the present invention the hydroxy protecting group R 5 is alkylsilyl, such as triethylsilyl, and the hydroxy protecting group R 6 is alkylsilyl, such as tert-butyldimethylsilyl. [0088] Compounds and intermediates of the present invention may comprise asymmetrically substituted (chiral) carbon atoms and carbon-carbon double bonds which may give rise to the existence of isomeric forms, e.g. enantiomers, diastereomers and geometric isomers. Epimers are known as diastereomers that have opposite configuration (R or S) at only one of multiple tetrahedral stereogenic centres in molecules having multiple stereogenic centres, such as the vitamin D analogues to which the present invention is directed. Designation of, for example, C-24 as the epimeric centre of a pair of enantiomers therefore implies that the configuration at the other stereogenic centres of the pair are identical. The present invention relates to all isomeric forms, such as epimers, either in pure form or as mixtures thereof. Pure stereoisomeric forms of the compounds and the intermediates of this invention may be obtained by the application of procedures known in the art, such as by chromatography or crystallisation, or by stereoselective synthesis. [0089] The indication of a specific conformation or configuration either in the formulas or the names of compounds or intermediates of the present invention shall indicate that this specific conformation or configuration is a preferred embodiment of the invention. The indication of a specific conformation or configuration either in the formulas or the names of compounds or intermediates of the present invention shall include any other isomer than specifically indicated, either in pure form or as mixtures thereof, as a further embodiment of the present invention. METHODS OF PREPARATION [0090] Compounds of general structure IIIa can for example be synthesised according to methods disclosed for example by M. J. Calverley, Tetrahedron, Vol. 43, No. 20, pp. 4609-4619, 1987 or in WO 87/00834. For example compound IIIa, wherein both R 1 and R 2 are tert-butyldimethylsilyl which preparation is described in these references can be deprotected with aqueous hydrofluoric acid in acetonitrile or with tetrabutylammonium fluoride to give a mixture of compounds wherein R 1 or R 2 are hydrogen, or to give a compound wherein R 1 and R 2 are hydrogen. This mixture of compounds can for example be separated by chromatography or crystallised as generally described herein. By reaction of said compounds of general structure IIIa, wherein R 1 and/or R 2 are hydrogen with a suitable protecting agent, new groups R 1 and/or R 2 can be introduced. Depending on the stoichiometry of the protecting agent used and the reaction conditions, mixtures of unprotected, monoprotected, and deprotected compounds can be obtained. Any intermediate of a mixture wherein one of R 1 or R 2 is hydrogen can then be isolated by chromatography and reacted with suitable protecting agent different from the first one used, to give compounds of general structure IIIa, wherein R 1 is different from R 2 . [0091] Compounds of general structure IIIb can be obtained from compounds of general structure IIIa by photo isomerisation, such as with UV-light in the presence of a triplet sensitizer, such as anthracene or 9-acetylanthracene. Such processes are well known to a person skilled in the art of vitamin D-derivatives and are for example described by M. J. Calverley, Tetrahedron, Vol. 43, No. 20, pp. 4609-4619, 1987 or in WO 87/00834 which are hereby incorporated by reference. [0092] Compounds of general structure VIa and/or VIb can be obtained from compounds of general structure IIIa or IIIb by treatment of a compound of general structure IIIa or IIIb with sulphur dioxide. The sulphur dioxide used can be liquid, gaseous or being dissolved in a suitable solvent. Suitable solvents for this Diels-Alder type reaction are all solvents, which are compatible with the reaction conditions, such as alkanes, such as hexane or heptane, hydrocarbons, such as xylenes, toluene, ethers, such as diethyl ether or methyl-tert-butyl ether (MTBE), acetates, such as ethyl acetate or 2-propyl acetate, halogenated solvents such as dichloromethane, or mixtures of said solvents, such as a mixture of a water immiscible solvent and water, e.g. toluene and water. The reaction can also be carried out in neat sulphur dioxide without a solvent. A suitable reaction temperature of the process is −50° C. to 60° C., such as −30° C. to 50° C., such as −15° C. to 40° C., such as −5° C. to 30° C., such as 0° C. to 35° C., such as 5° C. to 30° C. most such as 10° C. to 25° C., such as 15° C. to 20° C. Preferably the sulphur dioxide is used in excess (mol/mol), such as 5-100 molar excess, such as 7-30 molar excess, such as 10-15 molar excess. Any excess of unreacted sulphur dioxide can be removed from the reaction mixture by e.g. washing with aqueous base, such as aqueous sodium hydroxide or by distilling the sulphur dioxide off, optionally together with a solvent, optionally under reduced pressure. Reacting compounds of general structure IIIa with sulphur dioxide usually leads to mixtures of the two epimers VIa and VIb. The molar ratio VIa/VIb of the mixture of the epimers obtained in the Diels-Alder reaction will depend on the groups R 1 and R 2 and the reaction conditions used. [0093] Compounds of general structure XVa and XVb can for example be synthesised as previously described in EP 0078704 for R 1 =tert-butyldimethylsilyloxy (Example 11 (c). Compounds XVa and XVb, wherein R 1 is tert-butyldimethylsilyl can for example be deprotected with a suitable deprotecting reagent, such as aqueous hydrofluoric acid in acetonitrile or with tetrabutylammonium fluoride to give compounds, wherein R 1 is hydrogen, which then can be reacted with a suitable protecting agent, to give compounds of general structure XVa and XVb with a group R 1 different from the starting compound. Furthermore compounds of general structure XVa and XVb can be synthesised by ozonolysis of compounds 6a, 6b, 7a, or 7b disclosed in Tetrahedron, Vol. 43, No. 20, pp. 4609-4619, 1987. [0094] Compounds of general structure XIIIa can for example be synthesised starting from the sulphur dioxide adducts XVa and XVb by base assisted retro Diels-Alder reaction, such as described below. Different groups R 1 may be introduced, before or after the retro Diels-Alder reaction, by methods well known to a person skilled in the art of organic chemistry and as for example described above for compounds of general structure IIIa. [0095] Compounds of general structure XIIIb can be obtained from compounds of general structure XIIIa, and vice versa, by photo isomerisation as described above. [0096] The C,D-ring building blocks of general structure IXX can for example be prepared from vitamin D 2 (ergocalciferol) by methods disclosed in Eur. J. Org. Chem, 2003, 3889-3895; J. Med. Chem. 2000, 43, 3581-3586; J. Med. Chem. 1995, 38, 4529-4537, Chemical Reviews, 1995, Vol. 95, No. 6, and J. Org. Chem. 1992, 57, 3173-3178. Different groups R 5 can be introduced by using standard protection group chemistry such as described herein. [0097] The sulphur dioxide adducts of the present invention are preferably converted to the unprotected triene derivatives in the presence of a base in a retro Diels-Alder reaction. The reaction may be carried out in all solvents, which are compatible with the reaction conditions, such as alkanes, such as hexane or heptane, hydrocarbons, such as xylenes, toluene, ethers, such as diethyl ether or methyl-tert-butyl ether (MTBE), acetates, such as ethyl acetate or 2-propyl acetate, halogenated solvents such as dichloromethane, water or mixtures of said solvents. Methods of this retro Diels Alder type reaction are well known to a person skilled in the art of vitamin D synthesis (see e.g. M. J. Calverley, Tetrahedron, Vol. 43, No. 20, pp. 4609-4619, 1987 or in WO 87/00834). Preferred solvents are toluene, tert-butyl methyl ether, water, or mixtures thereof. Suitable bases to be used in the retro Diels-Alder reaction include, but are not limited to NaHCO 3 , KHCO 3 , Na 2 CO 3 , or K 2 CO 3 . In a preferred embodiment of the present invention, the base is aqueous NaHCO 3 and/or the retro Diels-Alder reaction is run above 60° C., such as between 60° C. and 120° C., most preferably above 70° C., such as between 74° C. and 79° C., typically for about one-two hours. [0098] Compounds of general structure VIa and/or VIb can be further obtained by ozonolysis of the SO 2 adducts of 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-9,10-seco-ergosta-5,7(E),10(19),22(E)-tetraene as for example described in Tetrahedron, Vol. 43, No. 20, pp. 4609-4619, 1987, optionally followed by deprotection and protection of the hydroxy groups as described above for compounds of general structure IIIa and/or IIIb. [0099] The synthetic methods used in the present invention are well known to a person skilled in the art of vitamin D synthesis or organic chemistry. Suitable reaction conditions can e.g. be found in Tetrahedron, Vol. 43, No. 20, pp. 4609-4619, 1987, in WO 87/00834, in WO 94/15912, in U.S. Pat. No. 69,553,962, and in Chemical Reviews, 1995, Vol. 95, No. 6; and the references cited therein, all of which hereby are incorporated by reference. [0100] The reduction of the compounds of general structure VIIIa and/or VIIIb, or XVIa and/or XVIb respectively, or XX is preferably carried out by reacting with a chiral borane reducing agent, such as a chiral oxaborolidines or oxazaborolidines, such as chiral oxazaborolidine reagents derived from N,N-diethylaniline-borane and (1S,2R)-cis-1-amino-2-indanol, (1R,2S)-cis-1-amino-2-indanol, (1S,2R)-cis-1-amino-2-indanol, (S)-prolinol, (R)-prolinol or B-(3-pinanyl)-9-borabicyclo[3.3.2]nonane (alpine-borane), or e.g. 5,5-diphenyl-2-methyl-3,4-propano-1,3,2-oxazaborolidine, (S)-2-methyl-CBS-oxazaborolidine, (R)-2-methyl-CBS-oxazaborolidine. These reduction methods and methods for the preparation of the compounds of general structure VIIIa and/or VIIIb have been described in detail in U.S. Appl. No. 60/553,962. The molar ratio of chiral auxiliary/reducing agent is preferably in the range of 2.3-2.7. The reduction reaction is usually carried out in a temperature interval between 5° C. to 35° C., preferably 10° C. to 30° C., preferably 15° C. to 25° C., most preferably 15° C. to 20° C. The reducing agent is preferably used in an equimolar amount or in molar excess to a compound of general structure VIIIa and/or VIIIb, or XVIa and/or XVIb respectively, or XX, such as in 2.5-3.0 molar excess. [0101] The process results in the enantioselective/diastereoselective reduction of the prochiral ketone of general structure VIIIa and/or VIIIb, or XVIa and/or XVIb respectively, or XX, such that the C-24 epimers XIa and/or XIb, or XVIa and/or XVIb respectively, or XXIa (R 6 =hydrogen) are formed in preference. Such borane-catalysed reactions were for example reviewed by Deloux and Srebnik [Chem. Rev. 93, 763, 1993]. Examples of efficient catalysts based on chiral modified borane can for example be found in [A. Hirao, J. Chem. Soc. Chem. Commun. 315, 1981; E. J. Corey, J. Am. Chem. Soc. 109, 7925, 1987]. Examples of the synthesis and/or use of e.g. 1,2- and 1,3-amino alcohols in stereoselective reduction with borane can e.g. be found in [E. Didier et al.; Tetrahedron 47, 4941-4958, 1991; C. H. Senanayake et al., Tetrahedron Letters, 36(42), 7615-18, 1995, EP 0698028, EP 0640089, EP 0305180, WO 93/23408, WO 94/26751]. The synthesis and/or use of chiral cis-1-amino-2-indanol derivatives in borane reductions can e.g. be found in [C. H. Senanayake, Aldrichimica Acta, 31 (1), 1-15, 1998; A. K. Ghosh et. al., Synthesis, 937-961, 1998; Y. Hong et. al., Tetrahedron Letters, 35(36), 6631-34, 1994; B. Di Simone, Tetrahedron Asymmetry, 6(1) 301-06, 1995; Y. Hong et al., Tetrahedron Letters, 36(36), 6631-34, 1994; R. Hett et al., Org. Process Res. & Dev., 2, 96-99, 1998; or EP 0763005], and references cited therein. [0102] The method for producing calcipotriol as described herein may be modified with regard to the order of the reaction steps, by omitting one or more reaction steps, or by introducing additional purification or reaction steps at any stage of the reaction sequence. The present invention includes all such modifications. A person skilled in the art of vitamin D chemistry or organic chemistry will know where such modifications can be made. [0103] The method for producing calcipotriol as described herein includes further all variants, where the hydroxy protecting groups R 1 and/or R 2 for compounds or intermediates, where R 1 and/or R 2 are not hydrogen, are removed at any stage of the reaction sequence. Compounds or intermediates, where R 1 and/or R 2 are hydrogen may be protected with protecting agents at any stage of the reaction sequence, including protecting agents which yield other protecting groups than those removed earlier in the reaction sequence. [0104] The reduction of a compounds of general formula XIVa, XIVb, XVIa, XVIb, XX, Va, Vb, VIIIa, and/or VIIIb with a suitable reducing agent in an inert solvent will, depending on the reducing agent and the reaction conditions used, give a mixture of the C-24 epimers of the corresponding alcohols formed, such as the compounds of general structures IXa and IXb, or such as the compounds of general structure Xa and Xb, or such as the compounds of general structure XIaa and XIab or XIba and XIbb, or such as XXIa and XXIb. Depending of the composition of the mixture, the desired epimers XXIa, IXa, Xa, XIaa, or XIba are advantageously separated by common purification methods known to the skilled person in the art before proceeding in the reaction sequence. [0105] The separation, isolation, and purification methods of the present invention include, but are not limited to chromatography, such as adsorption chromatography (including column chromatography and simulated moving bed (SMB)), crystallisation, or distillation. The separation, isolation, and purification methods may be used subsequently and in combination. Column chromatography, useful for the separation of vitamin D analogues of the present invention is well known to those skilled in the art of pharmaceutical chemistry. The technique employs a column packed with a stationary phase, for example silica, such as pretreated silica onto which sample to be separated is loaded. The sample is then eluted with a suitable eluent. Elution can be isocratic or so-called solvent programmed (gradient), wherein the composition of the eluent is varied regularly (e.g. linearly) or irregularly (e.g. stepwise over time. Pretreated silica gel, well known to a person skilled in the art of chromatography, is a suitable stationary phase. Elution with 5% (v:v) ethyl acetate in hexane or heptane followed by neat ethyl acetate is but one example of an elution program that produces the desired separation. Other suitable eluents will be deduced by the skilled person through routine methods of development, e.g. by using mixtures of heptane and ethylacetate of suitable polarity. [0106] For the chromatography steps, any combination of stationary phase (packing) and eluent that is capable of resolving the mixtures, e.g. if C-24 epimers, can be used. Such combinations can be readily determined by the skilled person by routine experimentation. [0107] The Horner-Emmons reagents of general structure VII can be synthesized by various synthetic approaches, ranging from the direct Arbuzov reaction of trisubstituted phosphites, e.g. trialkylphosphites, such as triethylphosphite or trimethylphosphate, with 2-halo-1-cyclopropylethanone, such as 2-chloro-1-cyclopropylethanone or 2-bromo-1-cyclopropylethanone [B. A. Arbuzov, Pure Appl. Chem. 1964, 9, 307] to methods using organometallic reagents (see for example references 5 (a)-(k) in [B. Corbel et al., Synth. Communications, 1996, 26(13), 2561-2568]). Other methods of preparation include the Michaelis-Becker process [G. Sturtz, Bull. Soc. Chim. Fr., 1964, 2333] and the use of masked carbonyl compounds (see for example references 8 (a)-(k) in [B. Corbel et al., Synth. Communications, 1996, 26(13), 2561-2568]. A safe and economical procedure for the preparation of β-keto phosphonates is based on the acylation of magnesium enolate derivative of trialkylphosphonoacetate using magnesium chloride-triethylamine followed by decarboxylation [D. Y. Kim, Synth. Commun. 1996, 26(13), 2487-2496; B. Corbel et al., Synth. Commun., 1996, 26(13), 2561-2568]. Another approach is based on the reactions of α-halophosphonates with esters promoted by a soluble Co(0) complex or by magnesium metal [F. Orsini, Synthesis, 2002, 12, 1683-1688]. Many other procedures are described in the literature and can for example be found in references cited in the above articles, e.g. by D. Y. Kim et al. and by F. Orsini et al. [0108] The Wittig-Horner reaction is usually performed by mixing a compound of general structure IXX, XXII, IIIa, IIIb, VIa and/or VIb, XIIIa, XIIIb, XVa and/or XVb with a phosphonate and a base in an appropriate solvent. The addition of reagents may be in either order, though the addition of the base as the last reagent to the stirred mixture can be advantageously depending on the base used. [0109] Preferably, the phosphonates of the general structure VII include groups R 3 and/or R 4 , which render the corresponding phosphate esters XII water soluble, as this will allow the removal of the phosphate esters XII by aqueous extraction from the reaction mixture. [0110] For example those groups of R 3 and/or R 4 of compounds VII or XII are advantageous, which result in a water solubility for compounds of general structure XII of at least 0.1 mg/ml at pH 9.5 and 20° C., such as at least 0.5 mg/ml at pH 9.5 and 20° C., such as at least 1 mg/ml at pH 9.5 and 20° C., such as at least 5 mg/ml at pH 9.5 and 20° C., such as at least 10 mg/ml at pH 9.5 and 20° C. [0111] In a another embodiment of the invention, phosphonates of general structure VII are preferred, where the water solubility of the corresponding phosphonic acid XII is equal or higher in comparison to the solubility of phosphonic acid XII where R 3 and R 4 are ethyl. Appropriate solvents for the Wittig-Horner reaction include hydrocarbons, such as xylenes, toluene, hexanes, heptanes, cyclohexane, and ethers, such as tert-butyl methyl ether, diethyl ether, 1,4-dioxane, diethoxymethane, 1,2-dimethoxyethane, or tetrahydrofuran, and other solvents such as acetonitrile, 2-methyltetrahydrofuran, diglyme, monoglyme, NMP, DMF, DMSO, or acetates, such as ethyl acetate or 2-propyl acetate, or halogenated solvents such as dichloromethane, chlorobenzene, or water, or mixtures of said solvents. [0112] In a preferred embodiment of the invention the reaction is carried out under phase transfer conditions using a mixture of water and a water-immiscible solvent, such as toluene or xylene with a suitable phase transfer catalyst, such as a tetraalkylammonium salt, e.g. a tetrabutylammonium hydroxide, halide, or hydrogensulfate, such as tetrabutylammonium bromide or chloride, or tetrabutylammonium hydrogensulfate. [0113] Suitable bases for the Wittig-Horner reaction include hydroxides, such as tetraalkylammonium hydroxides, e.g. tetrabutylammoniumhydroxide, or alkalimetalhydroxides, such as sodium hydroxide, potassium hydroxide, or group 2 element hydroxides, such as Mg(OH) 2 , including aqueous solutions of such hydroxides. Other suitable bases include, depending on the reaction conditions and solvents used, sodium hexamethyldisilazane (NaHMDS) or hydrides, such as sodium or calcium hydride, or alkoxides, such as sodium ethoxide, potassium tert-butoxide, or lithium tert-butoxide. [0114] The reaction temperature for the Wittig-Horner reactions will depend on the reaction conditions and solvents used. Typically for the reaction of compounds of general structure VIa and/or VIb, or XVa and/or XVb, reaction temperatures above 50° C. should be avoided. Suitable reaction temperature for the Wittig-Horner reaction of VIa and/or VIb, or XVa and/or XVb, are in the range of −80° C. to 50° C., such as −50° C. to 50° C., such as −30° C. to 50° C., such as −15° C. to 40° C., such as −5° C. to 35° C., such as 0° C. to 35° C., such as 5° C. to 30° C., such as 10° C. to 30° C., such as 1° C. to 30° C., such as 10° C. to 25° C., such as 5° C. to 20° C. Suitable reaction temperature for the Wittig-Horner reaction of IXX, XXII, IIIa, IIIb, XIIIa, or XIIIb are in the range of −80° C. to 150° C., such as −50° C. to 150° C., 40° C. to 120° C., such as −30° C. to 100° C., −20° C. to 80° C., such as −15° C. to 60° C., such as −10° C. to 50° C. such as −5° C. to 40° C., such as 0° C. to 35° C., such as 5° C. to 30° C., such as 10° C. to 30° C., such as 15° C. to 30° C., such as 10° C. to 25° C., such as 5° C. to 20° C. [0115] The phosphonate VII or XXIIIb is usually used in an equimolar amount or in molar excess with regard to the aldehydes, such as 100% excess, or 30% excess, or 50% excess, or 65% excess, or 70% excess, or 80% excess, or 90% excess, or 100% excess, or 150% excess, or 200% excess, or 300% excess. [0116] The base is usually used equimolar or in molar excess with regard to the phosphonate VII or XXIIIb, such as 10% excess, or 30% excess, or 50% excess, or 65% excess, or 70% excess, or 80% excess, or 90% excess, or 100% excess, or 150% excess, or 200% excess, or 300% excess, or 350% excess, or 400% excess, or 425% excess, or 450% excess, or 500% excess. [0117] The optimal reaction conditions for the Wittig-Horner reaction, such as the solvents, bases, temperature, work-up procedures, stoichiometries, or the reaction times will depend on the starting compounds, e.g. the groups R 1 and/or R 2 in the aldehydes of general structure IIIa, IIIb, VIa, VIb, XIIIa, XIIIb, XVa, or XVb, and the group R 6 of the aldehydes XXII, and the phosphonates VII and XXIIIb, e.g. the groups R 3 and R 4 . [0118] The stereoselectivity (trans-selectivity) of the reaction may be controlled by the reaction conditions and the choice of the phosphonate VII and XXIIIb (groups R 3 and R 4 ). [0119] The oxidation of the compounds of general structure XXIa, wherein R 5 is hydrogen and R 6 is hydrogen or preferably a hydroxy protecting group, such as tert-butyldimethylsilyl, to a compound of general structure XXII may for example be performed with pyridinium dichromate (PDC), Dess-Martin reagent, pyridinium chlorochromate (PCC), N-methylmorpholine N-oxide (NMO), such as N-methylmorpholine N-oxide on silica, tetrapropylammonium perrhutenate, for example in dichloromethane. [0120] The Wittig reagent XXIIIa can be prepared according to the methods described in Chemical Reviews, 1995, Vol. 95, No. 6 and J. Org. Chem. 2002, 67, 1580-1887. The Wittig Horner reagent XXIIIb may for example be prepared from compound 6 disclosed in J. Org. Chem. 2002, 67, 1580-1887, followed by reaction with suitable halogenating agent, such as thionyl chloride, and reaction of the resulting halogenide or chloride with triethyl phosphate in a Michaelis Arbuzov reaction, such as by heating with triethylphosphite. [0121] Coupling conditions of coupling compound XXII with XXIIIa or XXIIIb can also be found in Chemical Reviews, 1995, Vol. 95, No. 6, or J. Org. Chem. 2002, 67, 1580-1887, and references cited therein. A suitable base is for example an lithiumalklyl derivative, such as sec-butyl lithium or n-butyllithium. [0122] Hydroxylation, such as hydroxylation of the compound of general structure XIVa can be achieved with a suitable hydroxylating agent, for example by a selenite mediated allylic hydroxylation, such as under the conditions developed by Hesse, e.g. with selene dioxide (SeO 2 ), such as with SeO 2 and N-methylmorpholine N-oxide in refluxing methanol and/or dichloromethane) [J. Org. Chem. 1986, 51, 1637] or as described in Tetrahedron Vol. 43. No. 20, 4609-4619, 1987 or in WO87/00834. The undesired hydroxy epimer formed during hydroxylation may be removed by the general separation and chromatography methods described herein. [0123] Calicpotriol hydrate can be obtained by crystallisation of calcipotriol from aqueous solvents, such as for example by methods described in WO 94/15912. EXAMPLES [0000] General: [0124] All chemicals, unless otherwise noted were from commercial sources. For 1 H nuclear magnetic resonance (NMR) spectra (300 MHz) and 13 C NMR (75.6 MHz) chemical shift values (δ) (in ppm) are quoted, unless otherwise specified; for deuteriochloroform solutions relative to internal tetramethylsilane (δ=0.00) or chloroform (δ=7.26) or deuteriochloroform (6=76.81 for 13 C NMR) standard. The value of a multiplet, either defined (doublet (d), triplet (t), quartet (q)) or not (m) at the approximate mid point is given unless a range is quoted. All organic solvents used were of technical grade. Chromatography was performed on silica gel optionally using the flash technique. Preferably the silica was from Merck KGaA Germany: LiChroprep® Si60 (15-25 μm). Appropriate mixtures of ethyl acetate, dichloromethane, methanol, hexane and petroleum ether (40-60) or heptane were used as eluents unless otherwise noted. [0125] Experimental conditions regarding melting points, elemental analysis, UV-VIS absorption, 1 H NMR, and mass spectrometry data were, unless otherwise noted, as described by M. J. Calverley in Tetrahedron, Vol. 43, No. 20, p. 4614-15, 1987. [0000] Preparation 1: (2-cyclopropyl-2-oxoethyl)phosphonic acid diethyl ester [0000] Compound VII (R 3 , R 4 =ethyl) [0126] Cyclopropane carbonyl chloride (ALDRICH) (125 g) was added slowly to a mixture of anhydrous magnesium chloride (102 g), triethylphosphonoacetate (219 g), and triethyl amine (310 g) in toluene (1600 ml) with stirring keeping the temperature below 25° C. The mixture was stirred for another 30 minutes followed by the cautious addition of first water (950 ml), followed by a mixture of concentrated hydrochloric acid (250 ml) and water (350 ml), keeping the temperature below 25° C. The organic phase was separated, washed with an aqueous sodium chloride (400 g NaCl in 1200 ml water) and then washed with water (1600 ml). The organic phase was then concentrated in vacuo to the lowest possible volume to give 3-cyclopropyl-2-(diethoxyphosphoryl)-3-oxo-propionic acid ethyl ester as an oil. Water was added (40 ml) to the oil and this mixture was refluxed for approximately 3 hours. More water (2000 ml) was added to the reaction mixture and the title compound was extracted with methylene chloride. The solvents were removed in vacuo to give the title compound as oil. The 31 P NMR, and mass spectrometry data were found to be in full accordance with structure. 1 H NMR (CDCl 3 ): 4.16 (m,4H), 3.21 (d,2H), 2.20 (m,1H), 1.34 (t,6H), 1.11 (m,2H), 0.98 (m,2H) ppm. [0000] Preparation 2: (2-cyclopropyl-2-oxoethyl)phosphonic acid dimethyl ester [0000] Compound VII (R 3 , R 4 =methyl) [0127] The same procedure as in Preparation 1 may be used, but using trimethylphosphonoacetate instead of triethylphosphonoacetate. The 31 P NMR, and mass spectrometry data were found to be in full accordance with the structure. 1 H NMR (CDCl 3 ): 3.80 (d,6H), 3.22 (d,2H), 2.17 (m,1H), 1.11 (m,2H), 0.98 (m,2H) ppm. Example 1 20(R),1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene [0000] Compound Va (R 1 , R 2 =tert-butyldimethylsilyl) [0128] A mixture of (2-cyclopropyl-2-oxoethyl)phosphonic acid diethyl ester (compound VII/R 3 , R 4 =ethyl) (46.0 g, 209 mmol), 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene (compound IIIa/R 1 , R 2 =tert-butyldimethylsilyl) prepared according to M. J. Calverley, Tetrahedron, Vol. 43, No. 20, pp. 4609-4619, 1987 (72.2 g, 126 mmol), toluene (1100 ml), water (122 ml), tetrabutyl ammonium bromide (3.13 g), and sodium hydroxide solution 27.7% (128.0 g) was stirred at 30° C. for approximately one hour followed by stirring at ambient temperature (15-25° C.) overnight. When the reaction was judged to be complete as checked by HPLC [Column LiChrosorb Si 60 5 μm 250×4 mm from Merck, 1.5 ml/min flow, detection at 270 nm, hexane/ethylacetate 100:2 (v:v)], water was added (500 ml). The pH of the reaction mixture was adjusted to pH 8.5-9.5 by addition of phosphoric acid solution (ca. 20%) keeping the temperature between 20-25° C. The organic phase was separated followed by the addition of hexane (200 ml) and methanol (170 ml). The organic phase was once washed with a mixture of water (670 ml), saturated aqueous sodium chloride (120 ml), and saturated aqueous sodium hydrogen carbonate (20 ml). The organic solvents were removed in vacuo and the remainder was dissolved in a mixture of methanol (500 ml) and hexane (580 ml), and the solution was then washed with water (400 ml). The organic solvents were again removed in vacuo and the remainder was crystallised from tert-butyl methyl ether/methanol. The crystals were filtered off, washed twice with methanol and dried under vacuum to give the title compound 20(R),1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene (65.2 g, 102 mmol). The melting point, elemental analysis, UV-VIS absorption, and mass spectrometry data were found to be in full accordance with the structure as described earlier by M. J. Calverley in Tetrahedron, Vol. 43, No. 20, p. 4616, 1987 for compound 17. 13 C NMR (CDCl 3 ): 200.4, 153.4, 151.8, 142.5, 135.5, 128.1, 121.4, 116.5, 106.5, 70.0, 67.0, 56.0, 55.3, 46.0, 43.7, 40.2, 40.1, 36.4, 28.7, 27.4, 25.7, 25.6, 23.2, 22.1, 19.3, 18.5, 18.1, 17.9, 12.1, 10.7, 10.7, −5.0, −5.0, −5.1, −5.1 ppm. Example 1A 20(R), 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene [0000] Compound Va (R 1 , R 2 =tert-butyldimethylsilyl) [0129] To a solution of (2-cyclopropyl-2-oxoethyl)phosphonic acid diethyl ester (compound VII/R 3 , R 4 =ethyl) (1.51 g) and THF (16 ml) was added NaHMDS (sodium hexamethyldisilazane) (3.2 ml, 2M in THF) over 10 min below −50° C. and stirred additionally for 3-4 hr followed by addition of a solution of 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene (compound IIIa/R 1 , R 2 =tert-butyldimethylsilyl) (2 g) in THF (3 ml) below −50° C. The reaction was stirred additionally for 2 hr below −50° C. and then 2 hr at −25° C. before the temperature was elevated to room temperature overnight. The reaction was checked for completion by HPLC [Column LiChrosorb Si 60 5 μm 250×4 mm from Merck, 1.5 ml/min flow, detection at 270 nm, hexane/ethylacetate 100:2 (v:v)]. Example 1B 20(R),1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene [0000] Compound Va (R 1 , R 2 =tert-butyldimethylsilyl) [0130] To a solution of (2-cyclopropyl-2-oxoethyl)phosphonic acid diethyl ester (compound VII/R 3 , R 4 =ethyl) (1,51 g) and THF (16 ml) was added NaH (265 mg) over 3 min below −50° C. and stirred additionally for 2-3 hr followed by addition of a solution of 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene (compound IIIa/R 1 , R 2 =tert-butyldimethylsilyl) (2.1 g) in THF (3 ml) below −50° C. The reaction was stirred further for 2 hr below −50° C. and then 3.5 hr at −25° C. before the temperature was elevated to room temperature overnight. The reaction was checked for completion by HPLC [Column LiChrosorb Si 60 5 μm 250×4 mm from Merck, 1.5 ml/min flow, detection at 270 nm, hexane/ethylacetate 100:2 (v:v)]. Example 1C 20(R),1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene [0000] Compound Va (R 1 , R 2 =tert-butyldimethylsilyl) [0131] To a solution of (2-cyclopropyl-2-oxoethyl)phosphonic acid dimethyl ester (compound VII/R 3 , R 4 =methyl) (1,51 g) and THF (16 ml) was added NaHMDS (3.2 ml, 2M in THF) over 10 min below −50° C. and stirred further 4 hr followed by addition of a solution of 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene (compound IIIa/R 1 , R 2 =tert-butyldimethylsilyl) (2 g) in THF (3 ml). The reaction was stirred additionally for 2 hr below −50° C. and then 2 hr at −25° C. before the temperature was elevated to room temperature overnight. The reaction was checked for completion by HPLC [Column LiChrosorb Si 60 5 μm 250×4 mm from Merck, 1.5 ml/min flow, detection at 270 nm, hexane/ethylacetate 100:2 (v:v)]. Example 1D 20(R) 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene [0000] Compound Va (R 1 , R 2 =tert-butyldimethylsilyl) [0132] A mixture of (2-cyclopropyl-2-oxoethyl)phosphonic acid dimethyl ester (compound VII/R 3 , R 4 =methyl) (1.08 g), 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene (compound IIIa/R 1 , R 2 =tert-butyldimethylsilyl) (1.28 g), toluene (15 ml), water (1.2 ml), tetrabutyl ammonium bromide (49 mg), and sodium hydroxide solution 27.7% (1.54 ml) was stirred at 33° C. overnight. The reaction was checked for completion by HPLC [Column LiChrosorb Si 60 5 μm 250×4 mm from Merck, 1.5 ml/min flow, detection at 270 nm, hexane/ethylacetate 100:2 (v:v)]. [0000] Preparation 3: 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(Z),7(E),10(19)-triene [0000] Compound IIIb (R 1 , R 2 =tert-butyldimethylsilyl). [0133] 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene (compound IIIa/R 1 , R 2 =tert-butyldimethylsilyl) may be photoisomerised in toluene using anthracene as triplet sensitizer followed by chromatography of the crude product to give the title compound. 13 C NMR (CDCl 3 ): 204.8, 148.1, 139.7, 135.4, 122.7, 118.2, 111.1, 71.9, 67.3, 55.4, 51.3, 49.6, 46.0, 45.9, 44.6, 40.1, 28.6, 26.3, 25.7, 25.6, 23.1, 22.3, 18.0, 18.0, 13.4, 12.2, −4.9, −5.0, −5.3 ppm. Example 2 20(R),1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(Z),7(E),10(19)-triene [0000] Compound Vb (R 1 , R 2 =tert-butyldimethylsilyl). [0134] The same procedure as in Example 1 may be used, using 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(Z),7(E),10(19)-triene (compound IIIb/R 1 , R 2 =tert-butyldimethylsilyl) as the starting material, except that the product may be purified by chromatography instead of crystallisation to give the title compound. 1 H NMR (CDCl 3 ): 6.78 (dd,1H), 6.24 (d,1H), 6.16 (d,1H), 6.02 (d,1H), 5.19 (d,1H), 4.87 (d,1H), 4.38 (m,1H), 4.20 (m,1H), 2.85 (dd,1H), 2.46 (dd,1H), 2.38-1.20 (m,16H), 1.13 (d,3H), 1.08 (m,2H), 0.91 (m,2H), 0.89 (s,18H), 0.59 (s,3H), 0.07 (m,12H) ppm. [0000] Preparation 4: 1(S),3 (R)-dihydroxy-20(S)-formyl-9,10-secopregna-5(Z),7(E),10(19)-triene IIIb (R 1 , R 2 =hydrogen) [0135] 1 (S), 3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(Z),7(E),10(19)-triene (compound IIIb/R 1 , R 2 =tert-butyldimethylsilyl) from Preparation 3 may be deprotected with aqueous hydrofluoric acid (40%) to give the title compound IIIb (R 1 , R 2 =hydrogen) compound. 1 H NMR (CDCl 3 ): 9.58 (d,1H), 6.37 (d,1H), 6.04 (d,1H), 5.33 (s,1H), 4.99 (s,1H), 4.43 (m,1H), 4.23 (m,1H), 2.85 (dd,1H), 2.60 (dd,2H), 2.44-2.26 (m,2H), 2.10-1.30 (m,14H), 1.14 (d,3H), 0.60 (s,3H) ppm. Example 4 1(S),3(R)-dihydroxy-20(R)-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(Z),7(E),10(19)-triene [0000] Compound Vb (R 1 , R 2 =hydrogen) [0136] The same procedure as in Example 1 may be used, using 1(S),3(R)-dihydroxy-20(S)-formyl-9,10-secopregna-5(Z),7(E),10(19)-triene (compound IIIb/R 1 , R 2 =hydrogen) from Preparation IV as the starting material, except that the product may be purified by chromatography instead of crystallisation to give the title compound. 13 C NMR (CDCl 3 ): 200.8, 152.1, 147.7, 142.2, 133.5, 128.3, 124.7, 117.4, 111.8, 70.7, 66.8, 56.1, 55.5, 46.1, 45.2, 42.8, 40.3, 40.2, 29.0, 27.4, 23.5, 22.3, 19.5, 18.7, 12.3, 11.0 ppm. [0000] Preparation 5: 1(S),3(R)-bis(trimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(Z),7(E),10(19)-triene [0137] Compound IIIb (R 1 , R 2 =trimethylsilyl). [0138] 1(S),3(R)-dihydroxy-20(S)-formyl-9,10-secopregna-5(Z),7(E),10(19)-triene (compound IIIb/R 1 , R 2 =hydrogen) from Preparation 4 may be reacted with trimethyl silyl chloride in the presence of triethylamine in dichloromethane. The obtained raw product may be purified by chromatography to give the pure title compound. 13 C NMR (CDCl 3 ): 204.7, 147.8, 140.1, 135.2, 122.9, 118.1, 111.4, 71.4, 67.0, 55.4, 51.3, 49.5, 46.0, 45.7, 44.6, 40.1, 28.7, 26.3, 23.2, 22.3, 13.4, 12.2, 0.0, −0.1 ppm. [0000] Preparation 6: 1(S)-tert-butyldimethylsilyloxy-3(R)-hydroxy-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene [0000] IIIa (R 1 =hydrogen, R 2 =tert-butyldimethyl silyl), and 1(S)-hydroxy-3(R)-tert-butyldimethylsilyloxy-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene [0000] IIIa (R 1 =tert-butyldimethylsilyl, R 2 =hydrogen). [0139] 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene (compound IIIa/R 1 , R 2 =tert-butyldimethylsilyl) may be partially deprotected with tetrabutylammonium fluoride to give a mixture of the title compounds and the unprotected derivative IIIa (R 1 , R 2 =hydrogen). The compounds of the mixture may be separated by column chromatography to give pure fractions of the title compounds IIIa (R 1 =hydrogen, R 2 =tert-butyldimethylsilyl), 1 H NMR (CDCl 3 ): 9.59 (d,1H), 6.50 (d,1H), 5.86 (d,1H), 5.01 (s,1H), 4.94 (s,1H), 4.48 (t,1H), 4.24 (m,1H), 2.88 (dd,1H), 2.62 (dd,1H), 2.50-2.30 (m,2H), 2.11-1.30 (m,14H), 1.13 (d,3H), 0.88 (s,9H), 0.60 (s,3H), 0.06 (s,3H), 0.04 (s,3H) ppm; and IIIa (R 1 =tert-butyldimethylsilyl, R 2 =hydrogen), 1 H NMR (CDCl 3 ): 9.59 (d,1H), 6.49 (d,1H), 5.86 (d,1H), 5.07 (s,1H), 4.95 (s,1H), 4.49 (m,1H), 4.20 (m,1H), 2.87 (dd,1H), 2.52 (dd,1H), 2.45-2.30 (m,2H), 2.12-1.31 (m,14H), 1.13 (d,3H), 0.86 (s,9H), 0.59 (s,3H), 0.06 (s,6H) ppm. Example 5 1(S)-tert-butyldimethylsilyl-3(R)-hydroxy-20(R)-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene [0000] Compound Va (R 1 =hydrogen, R 2 =tert-butyldimethylsilyl) [0140] The same procedure as in Example 1 may be used, using 1(S)-tert-butyldimethylsilyl-3(R)-hydroxy-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene (compound IIIa/R 1 =hydrogen, R 2 =tert-butyldimethylsilyl) from Preparation 6 as the starting material, except that the product may be purified by chromatography instead of crystallisation gave the title compound. 1 H NMR (CDCl 3 ): 6.75 (dd,1H), 6.50 (d,1H), 6.14 (d,1H), 5.84 (d,1H), 5.00 (s,1H), 4.92 (s,1H), 4.47 (t,1H), 4.22 (m,1H), 2.85 (dd,1H), 2.62 (dd,1H), 2.43 (dd,1H), 2.29 (m,1H), 2.15-1.15 (m,15H), 1.11 (d,3H), 1.06 (m,2H), 0.87 (s,9H), 0.86 (m,2H), 0.59 (s,3H), 0.06 (s,3H), 0.04 (s,3H) ppm. Example 6 1(S)-hydroxy-3(R)-tert-butyldimethylsilyl-20(R)-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene [0000] Compound Va (R 1 =tert-butyldimethylsilyl, R 2 =hydrogen) [0141] The same procedure as in Example 1 may be used, using 1(S)-hydroxy-3(R)-tert-butyldimethylsilyl-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene (compound IIIa/R 1 =tert-butyldimethylsilyl, R 2 =hydrogen) from Preparation 6 as the starting material, except that the product may be purified by chromatography instead of crystallisation gave the title compound. 1 H NMR (CDCl 3 ): 6.76 (dd,1H), 6.49 (d,1H), 6.14 (d,1H), 5.85 (d,1H), 5.06 (s,1H), 4.95 (s,1H), 4.49 (m,1H), 4.19 (m,1H), 2.86 (dd,1H), 2.52 (dd,1H), 2.45-1.20 (m,17H), 1.12 (d,3H), 1.07 (m,2H), 0.88 (m,2H), 0.86 (s,9H), 0.59 (s,3H), 0.06 (s,6H) ppm. Example 7 20(R),1(S),3(R)-bis(tert-butydimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene SO 2 -adducts [0000] Compound VIIIa and VIIIb (R 1 , R 2 =tert-butyldimethylsilyl) [0142] A mixture of (2-cyclopropyl-2-oxoethyl)phosphonic acid diethyl ester (Compound VII R 3 , R 4 =ethyl) (30 g), 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene SO 2 -adducts (compounds VIa and VIb/R 1 , R 2 tert-butyldimethylsilyl) (34.8 g) (compounds 14a and 14 b described in M. J. Calverley, Tetrahedron, Vol. 43, No. 20, pp. 4609-4619, 1987), toluene (350 ml), water (35 ml), tetrabutyl ammonium bromide (1.01 g), and sodium hydroxide solution 27.7% (35 ml) was stirred at 33° C. for approximately 1.5 hour. When the reaction was judged to be complete as checked by HPLC [Column LiChrosorb Si 60 5 μm 250×4 mm from Merck, 1.5 ml/min flow, detection with MS, hexane/ethylacetate 100:2 (v:v)], water was added (160 ml). The pH of the reaction mixture was adjusted to pH 8.5-9.5 by addition of phosphoric acid solution (ca. 20%) keeping the temperature between 20-25° C. The organic phase was separated followed by the addition of MTBE (90 ml), water (600 ml), saturated aqueous sodium chloride (60 ml), and saturated aqueous sodium hydrogen carbonate (10 ml). The toluene phase was separated and the solvent removed in vacuo without heating (preferably below 30° C.) to give the two epimeric SO 2 -adducts VIIIa and VIIIb/R 1 , R 2 =tert-butyldimethylsilyl as a solid mixture predominantly containing VIIIa as checked by TLC. The two epimeric SO 2 -adducts VIIIa and VIIIb could be separated by chromatography. Crystalline VIIIa could be furthermore obtained by tituration of the solid mixture with methanol. 1 H NMR (CDCl 3 ) VIIIa/R 1 , R 2 =tert-butyldimethylsilyl=6.73 (dd,1H), 6.14 (d,1H), 4.69 (d,1H), 4.62 (d,1H), 4.35 (s,1H), 4.17 (m,1H), 3.92 (d,1H), 3.58 (d,1H), 2.61 (m,1H), 2.29 (m,1H), 2.2-1.2 (m,16H), 1.11 (d,3H), 1.05 (m,2H), 0.90 (m,2H), 0.87 (s,9H), 0.85 (s,9H), 0.68 (s,3H), 0.06 (s,3H), 0.05 (s,3H), 0.04 (s,3H), 0.02 (s,3H) ppm. Example 8 20(R),3(R)-(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E),10(19)-triene SO 2 -adducts [0000] Compound XVIa and XVIb (R 1 =tert-butyldimethylsilyl) [0143] The same procedure as in Example 7 using 3(R)-(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene SO 2 -adducts (mixture of the two epimeric SO 2 -adducts XVa and compound XVb) as the starting material giving the two epimeric SO 2 -adducts XVIa and XVIb/R 1 =tert-butyldimethylsilyl as a solid mixture predominantly containing XVIa as checked by TLC. The two epimeric SO 2 -adducts XVIa and XVIb could be separated by chromatography. Crystalline XVIa could be furthermore obtained by tituration of the solid mixture with methanol. 13 C-NMR (CDCl 3 ) (mixture of the two epimeric SO 2 -adducts XVIa and XVIb/R 1 =tert-butyldimethylsilyl) 200.3, 151.6, 151.4, 149.8, 149.2, 130.5, 130.1, 128.3, 128.1, 126.6, 126.3, 110.5, 110.0, 67.4, 66.7, 66.6, 66.3, 58.0, 57.9, 55.8, 55.6, 55.3, 55.2, 46.3, 45.5, 39.9, 39.7, 34.4, 34.1, 33.9, 31.4, 30.8, 30.5, 29.6, 29.1, 27.3, 27.1, 26.7, 25.6, 25.1, 24.4, 24.1, 23.6, 23.2, 22.4, 21.9, 21.9, 19.4, 19.3, 18.6, 18.4, 17.9, 17.9, 13.9, 12.2, 11.9, 10.8, −5.0 ppm. Example 9 20(R),3(R)-(tert-butyldimethylsilyloxy)-20-(3′-cyclopropyl-3′-oxoprop-1′(E)-enyl)-9,10-secopregna-5(E),7(E) 10(19)-triene [0000] Compound XIVa (R 1 =tert-butyldimethylsilyl) [0144] A mixture of ETH655 (2-cyclopropyl-2-oxoethyl)phosphonic acid diethyl ester (compound VII/R 3 , R 4 =ethyl) (22.4 g), 3(R)-(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene (compounds XIIIa/R 1 =tert-butyldimethylsilyl) (27 g) prepared according to M. J. Calverley, Tetrahedron, Vol. 43, No. 20, pp. 4609-4619, 1987, toluene (328 ml), water (35 ml), tetrabutyl ammonium bromide (0.93 g), and sodium hydroxide solution 27.7% (38 g) was stirred at 33° C. for approximately 1 hour. When the reaction was judged to be complete as checked by HPLC [Column LiChrosorb Si 60 5 μm 250×4 mm from Merck, 1.5 ml/min flow, detection at 270 nm, hexane/ethylacetate 100:2 (v:v)], water was added (150 ml). The pH of the reaction mixture was adjusted to pH 7.8 by addition of phosphoric acid solution (ca. 20%) keeping the temperature between 20-25° C. The organic phase was separated followed by the addition of water (2000 ml), saturated aqueous sodium chloride (36 ml), and saturated aqueous sodium hydrogen carbonate (6 ml). The organic solvents were removed in vacuo. 13 C NMR (CDCl 3 ) (compound XIVa/R 1 =tert-butyldimethylsilyl): 200.3, 151.8, 149.8, 142.8, 136.4, 128.1, 119.7, 116.1, 107.4, 69.2, 56.1, 55.3, 45.9, 40.2, 40.0, 37.3, 35.0, 30.9, 28.7, 27.3, 25.7, 23.2, 22.0, 19.3, 18.5, 18.0, 12.2, 10.7, −4.9 ppm. Example 10 1-Cyclopropyl-4-(4-triethylsilanyloxy-7a-methyl-octahydro-inden-1-yl)-pent-2-en-1-one [0000] Compound XX (R 5 =triethylsilyl) [0145] 2-(7a-Methyl-4-triethylsilanyloxy-octahydro-inden-1-yl)-propionaldehyde IX (R 5 =triehtylsilyl), which was synthesised as described in Eur. J. Org. Chem. 2003, pp. 3889-3895, (2 g) was added to a mixture of Li-tert.-butoxide (0.6 g) and (2-cyclopropyl-2-oxoethyl)phosphonic acid diethyl ester (compound VII/R 3 , R 4 =ethyl) (1.62 g) in THF (50 ml) at −50° C. After complete reaction the reaction was quenched with water (50 ml) and extracted with hexane (100 ml). The organic phase was filtered through silica gel and concentrated in vacuo to give compound XX (R 5 =triethylsilyl) as an clear oil (2 g). 1 H-NMR (CDCL 3 ): 6.74 (dd,1H), 6.12 (d,1H), 4.03 (m,1H), 2.40-0.80 (m,21H), 1.06 (d,3H), 0.94 (t,9H), 0.54 (q,6H) ppm. [0000] Preparation 7: 1-Cyclopropyl-4-(4-triethylsilanyloxy-7a-methyl-octahydro-inden-1-yl)-pent-2-en-1-(S)-ol [0000] Compound XXIa (R 5 =triethylsilyl) [0146] (1S,2R)-(−)-cis-1-amino-2-indanol (6.33 g, 0.87 eq.) was mixed with MTBE (100 ml) under a nitrogen atmosphere at 15-25° C. followed by the addition of N,N-diethylaniline-borane (16.0 ml, 1.85 eq.) at that temperature. The mixture was stirred until no more evolution of hydrogen could be observed. 1-Cyclopropyl-4-(4-triethylsilanyloxy-7a-methyl-octahydro-inden-1-yl)-pent-2-en-1-one (compound XX/R 5 =triethylsilyl) from Example 10 (19.0 g) was dissolved in MTBE (80 ml) at room temperature and then added dropwise to said mixture at 15-25° C. over 2 hours. The mixture was stirred for ca. 10 minutes after complete addition and then quenched with saturated aqueous NaHCO 3 (100 ml) and extracted with hexane (200 ml). The organic phase was separated and washed with 1 M hydrochloric acid (4×120 ml) at 0-10° C. followed by washing with saturated aqueous NaHCO 3 (100 ml) and water (50 ml) giving the mixture of compound XXIa and XXIb (R 5 =triethylsilyl) in a molar ratio of 87:13 as checked by HPLC analysis. {Column LiChrosorb Si 60 5 μm 250×4 mm from Merck 1 ml/min flow, MS-detection, hexane/ethylacetate 90:10 (v:v): RT XXIa=ca. 9.9 min, RT XXIb=ca. 8.4 min}. 1 H-NMR (CDCl 3 ) XXIa/R 5 =triethylsilyl: 138.0, 128.3, 76.6, 69.1, 56.2, 41.9, 40.5, 39.0, 34.4, 30.1, 27.4, 22.8, 20.0, 17.5, 17.3, 13.5, 6.7, 4.7, ppm; XXIb/R 5 =triethylsilyl: 138.2, 128.4, 77.1, 69.2, 56.1, 53.0, 41.9, 40.5, 39.1, 34.4, 27.5, 22.8, 20.0, 17.5, 17.4, 13.5, 6.7, 4.8 ppm.

The present invention relates to novel methods for the preparation of intermediates which are useful in the synthesis of cacipotriol. The present invention relates further to the use of intermediates produced with said methods for making calcipotriol or calcipotriol monohydrate.

TECHNOLOGICAL FIELD [0001] The invention generally provides processes for recovery of acid from acid-rich solutions and mixtures. BACKGROUND [0002] The regeneration of chemical-spent acid from industrial processes is highly desirable for a verity of reasons, ranging from reducing industrial waste and contamination of landfills to reduction of costs associated with the reproduction of acid. [0003] The recovery of acid has been demonstrated in a variety of industrial set-ups. [0004] U.S. Pat. No. 2,631,974 [1] discloses an electrolytic system for the recovery of certain ingredients from the waste liquors discharged from various chemical processes, in particular with the recovery of sulfate ions in acid aqueous solutions containing them by the conversion thereof into aqueous sulfuric acid solutions of sufficient purity to be of commercial value. [0005] U.S. Pat. No. 8,052,953 [2] discloses a method for recovering sulfuric acid from concentrated acid hydrolysate of plant cellulose material. [0006] One of the main barriers in utilizing acid in industrial applications is the relatively high cost which is associated mainly with a high energy requirement needed to recover it. Therefore, there is great need for reducing the production cost and energy requirements involved in such processes. [0007] Sulfuric acid is one of the more common acids in industrial use. The addition of hydrogen peroxide to sulfuric acid results in the formation of a very strong oxidizer, known as Caro's Acid or the Piranha solution, which has the ability to oxidize or hydroxylate most metal surfaces and remove most organic matter. The common application of the Piranha solution is in the microelectronics industry to clean photoresist residues from silicon wafers. It is also used to clean glassware by hydroxylating the surface, thus increasing the number of silanol groups on the surface. [0008] U.S. Pat. No. 3,856,673 [3] discloses a process for purifying a spent acid stream containing organic impurities and at least 60% sulfuric acid. The process disclosed utilizes a stoichiometric amount of an oxidizer such as hydrogen peroxide to achieve oxidation of organic materials such as nitrocresols and nitrophenolic compounds. [0009] Huling et al [4] teach oxidation of organic compounds utilizing hydrogen peroxide. REFERENCES [0000] [1] U.S. Pat. No. 2,631,974 [2] U.S. Pat. No. 8,052,953 [3] U.S. Pat. No. 3,856,673 [4] Huling S. G. and Pivetz B. E. In Situ Chemical Oxidation. Engineering Issue. Ground Water and Ecosystem Restoration Information Center, UAEPA, EPA/600/R-06/072 (2006) SUMMARY OF THE INVENTION [0014] The inventors of the present invention have developed a unique, efficient and cost-effective process for the recovery of acid from acid-rich solutions. The process of the invention utilizes a strong oxidizer, such as Caro's acid, to disintegrate or render insoluble organic or inorganic materials such as carbohydrates and complexes thereof contained in acid-rich solutions, to thereby make efficient and simple the separation and recovery of the acid solution. The acid recovered is thus obtained as an aqueous acid solution, being free of organic matter, and containing nearly all of the acid originally contained in the acid-rich solution. [0015] Thus, the invention described herein affords separating and recovering acids, such as sulfuric acid, from a variety of organic components such as hydrolysates of plant cellulose materials commonly used in the paper industry, such components may or may not be “in solution”, namely some or all of the organic components may be insoluble in the original acid-rich solution to be recovered. [0016] In one of its aspects, the present invention provides a process for acid recovery from an acid-rich aqueous solution, the solution comprising at least one acid to be recovered and at least one organic material (being different from the acid material and typically containing at least one carbohydrate material or a complex thereof), the process comprising: treating said solution with at least one oxidizer or at least one precursor of the oxidizer, wherein the oxidizer is capable of oxidizing the organic material contained in the solution into at least one insoluble or gaseous species; removing or allowing separation of said insoluble or gaseous species from the acid solution; [0019] to yield a substantially enriched acid solution, substantially free of organic matter (being free of said organic impurities, as disclosed herein). [0020] The invention further provides a process for recovery of acid, such as sulfuric acid, from an acid-rich mixture comprising at least one acid, e.g., sulfuric acid, and an amount of organic matter, the process comprising contacting the mixture with an oxidizer or a precursor thereof, thus producing an acid enriched solution, wherein the oxidized organic matter precipitates or evaporates from the acid enriched mixture. [0021] The enriched acid solution being substantially free of organic matter may be further treated to further remove traces of unoxidized organic matter, residues of oxidized organic matter and insoluble species. [0022] In some embodiments, the enriched acid solution being substantially free of organic matter contains up to 1,000 ppm of organic matter. [0023] The acid solution may be any acid-containing aqueous solution which is used or generated in any one of a variety of industries or industrial processes, ranging from stainless steel production to microchip manufacturing. As the acid content may vary based on the industry or the process producing the acid waste, the process of the invention may be suitably configured and adapted to achieve full recovery of the acid. [0024] In accordance with the invention, the oxidizer or a precursor thereof (e.g., hydrogen peroxide) is added to the acid-rich solution at room temperature. The reaction mixture comprising the acid-rich solution and the oxidizer or precursor thereof may be allowed to react over a period of between 1 hours and 7 days at room temperature (25-30° C.), at a temperature above 50° C., or at a temperature above 60° C., or at a temperature above 70° C., or at a temperature above 80° C., or at a temperature above 90° C., or at a temperature above 100° C., or at a temperature above 110° C., or at a temperature above 120° C., or at a temperature above 130° C., or at a temperature above 140° C., or at a temperature above 150° C., or at a temperature between 50° C. and 100°, or at a temperature between 60° C. and 110°, or at a temperature between 70° C. and 120°, or at a temperature between 80° C. and 130°, or at a temperature between 90° C. and 140°, or at a temperature between 100° C. and 150°, or at a temperature between 50° C. and 150°, or at a temperature between 60° C. and 140°, or at a temperature between 70° C. and 130°, or at a temperature between 80° C. and 120°, or at a temperature between 90° C. and 100° C. [0025] In accordance with the invention, the oxidizer or a precursor thereof (e.g., hydrogen peroxide) is added to the acid-rich solution at a temperature below room temperature (being the temperature at which the reaction mixture comprising the acid-rich solution and the oxidizer or precursor thereof may be allowed to react). In some embodiments, the temperature is between −30° C. (minus 30 degrees Centigrade) and 0° C. In some embodiments, the temperature is between −30° C. and −20° C. In some embodiments, the temperature is between −30° C. and −10° C. In some embodiments, the temperature is between −20° C. and −10° C. In some embodiments, the temperature is between −20° C. and 0° C. In some embodiments, the temperature is between −10° C. and 0° C. In some embodiments, the temperature is between −30° C. and 5° C. In some embodiments, the temperature is between −30° C. and 10° C. In some embodiments, the temperature is between −30° C. and 15° C. In some embodiments, the temperature is between −30° C. and 20° C. In some embodiments, the temperature is between −30° C. and 25° C. In some embodiments, the temperature is between −30° C. and 30° C. In some embodiments, the temperature is between 0° C. and 5° C. In some embodiments, the temperature is between 0° C. and 10° C. In some embodiments, the temperature is between 0° C. and 15° C. In some embodiments, the temperature is between 0° C. and 20° C. In some embodiments, the temperature is between 0° C. and 25° C. In some embodiments, the temperature is between 0° C. and 30° C. [0026] In some cases, the oxidizer or a precursor thereof is added to the acid-rich solution at room temperature and the temperature of the reaction mixture is allowed to increase spontaneously (in case of an exothermic reaction). In some embodiments, the temperature increase is controlled such that the temperature does not increase above 50° C., above 60° C., above 70° C., above 80° C., above 90° C., above 100° C., above 110° C., above 120° C., above 130° C., above 140° C., or to above 150° C. [0027] After the oxidizer completely oxidizes the organic material, traces of the organic material and the remaining oxidizing agents may be removed from the acid enriched solution using any method that is common in the field of the art. In some embodiments, the solid oxidized material and solid oxidizer may be removed by filtration. Where the oxidized material is a gaseous species, it may be removed from the acid-enriched solution by evaporation, by heating, under vacuum, by stirring, or by saturating the acid-enriched solution with an inert gas. [0028] In some embodiments, the trace materials and the remaining oxidizing agents may be removed by mechanical or chemical adsorption or by absorption e.g., on activated carbon, by flocculation or precipitation. [0029] The process of the invention may be repeated by employing consecutive cycles and using the herein defined substantially carbon-free acid formulation as a substrate in acid-based processes. [0030] The oxidizer used in accordance with the invention is typically a “strong oxidizer” which is capable of converting an organic material into one or more oxide forms which are less soluble or more easily evaporable as compared to the unoxidized form. The oxidizer is said of being a strong oxidizer as it is capable of oxidizing the majority of the organic material contained in the solution, namely 100 wt % of the organic material, 99%, 98%, 97%, 96%, 95%, 94%, 93%, 92%, 91%, 90%, between 80% and 100%, between 90% and 100%, between 80% and 95%, or between 80% and 90% of the organic material. Typically, the oxidized form of the organic material is insoluble in the acid solution or is easily removable from the acid solution, e.g., by evaporation, by filtration, by heating, under vacuum, by activated carbon, etc. [0031] In some embodiments, the oxidizer has a Standard Electrode Potentials)(E° greater than +1 Volts. [0032] In some embodiments, the oxidizer is selected to have E° between +1 and +2. The oxidizer is selected to effectively oxidize the organic material without substantially chemically affecting the acid component. Some non-limiting examples of oxidizers include ammonium perchlorate, ammonium permanganate, barium peroxide, bromine, calcium chlorate, calcium hypochlorite, chlorine trifluoride, chromium anhydride, chromic acid, dibenzoyl peroxide, fluorine, hydrogen peroxide, magnesium peroxide, nitrogen trioxide, perchloric acid, potassium bromated, potassium chlorate, potassium peroxide, propyl nitrate, sodium chlorate, sodium chlorite, sodium perchlorate, sulphuric acid and sodium peroxide. [0033] In some embodiments, the oxidizer is hydrogen peroxide (H 2 O 2 ). [0034] In other embodiments, the oxidizer is H 2 SO 5 (Caro's acid). In some embodiments, H 2 SO 5 (Caro's acid) is formed in situ. [0035] In some embodiments, the oxidizer is utilized for forming in situ a stronger oxidizer. [0036] According to embodiments where the oxidizer is formed in situ, an oxidizer (e.g., hydrogen peroxide) or a precursor of the oxidizer which is convertible into the oxidizer in the presence of the acid in the acid-rich solution, is added to the acid-rich solution and transforms an amount of the acid in the solution into the oxidizer. In embodiments where a precursor of the strong oxidizer is hydrogen peroxide and the acid is sulfuric acid, a small amount of “Caro's acid” forms in situ and oxidizes the carbon-based or carbon-containing material, e.g., carbohydrates, to at least one insoluble or gaseous species (e.g., CO 2 and SO 2 ) and water; thus, yielding a substantially carbon-free acid enriched solution (e.g., sulfuric acid). [0037] Thus, the invention also contemplates a process for acid recovery from an acid-rich aqueous solution, the solution comprising at least one organic material (being different from the acid material and selected, e.g., from carbohydrates and complexes thereof), the process comprising: treating said solution with Caro's acid or with at least one precursor thereof for enabling in situ formation of Caro's acid in the solution, wherein the organic material contained in the solution is transformed into at least one insoluble or gaseous species; removing or allowing separation of said insoluble or gaseous species from the acid solution; [0040] to yield a substantially enriched acid solution, substantially free of organic matter. [0041] As noted above, where Caro's acid is used in the process of the invention, the acid-rich solution may be treated with an amount of a pre-prepared Caro's acid or may be treated with an amount of sulfuric acid and hydrogen peroxide, step wise, to form in situ the Caro's acid and permit transformation of the organic material, as detailed herein. [0042] The invention further provides a process for recovery of sulfuric acid from an aqueous solution rich in sulfuric acid, the solution further comprising at least one soluble organic material, as defined herein, the process comprising: treating said solution with Caro's acid or with hydrogen peroxide, to transform the organic material contained in the solution into at least one insoluble or gaseous species; removing or allowing separation of said insoluble or gaseous species from the acid solution; [0045] to yield a substantially enriched acid solution, substantially free of organic matter. [0046] The “acid rich solution” is generally a formulation or a combination of materials or a mixture or a medium comprising between about 5% and between about 98% acid by weight, water and at least one carbon material. The acid in the acid-rich solution may be an organic or mineral acid. In some embodiments, the solution comprises between about 5% and about 90% acid by weight, or between about 30% and about 85% acid by weight, or between about 30% and about 80% acid by weight, or between about 30% and about 75% acid by weight, or between about 30% and about 60% acid by weight. [0047] In some embodiments, the solution comprises between about 35% and about 95% acid by weight, or between about 40% and about 95% acid by weight, or between about 45% and about 95% acid by weight, or between about 50% and about 95% acid by weight, or between about 55% and about 95% acid by weight. [0048] In some embodiments, the solution comprises between about 40% and about 90% acid by weight, or between about 50% and about 85% acid by weight, or between about 60% and about 80% acid by weight, or between about 60% and about 75% acid by weight, or between about 60% and about 65% acid by weight. [0049] In some embodiments, the solution comprises between about 60% and about 90% acid by weight, or between about 60% and about 85% acid by weight, or between about 60% and about 80% acid by weight, or between about 60% and about 75% acid by weight, or between about 60% and about 65% acid by weight, or between about 70% and about 90% acid by weight, or between about 70% and about 85% acid by weight, or between about 70% and about 80% acid by weight, or between about 70% and about 75% acid by weight, or between about 80% and about 95% acid by weight, or between about 80% and about 90% acid by weight, or between about 80% and about 85% acid by weight, or between about 90% and about 95% acid by weight. [0050] In some embodiments, the concentration of the acid in the acid-rich solution is between 1 and 98%, or between 30% and 63%. In other embodiments, the concentration of the acid is between 40% and 63%, between 59% and 63% or is between 60 and 64%. [0051] The acid to be recovered from the acid-rich solution may be a single type of acid or a combination of acids. The acid is usually recovered as an aqueous solution. [0052] As the process of the invention permits conversion of the organic soluble and insoluble materials contained in the acid-rich solution into insoluble organic materials or gaseous species, and permitting their removal, without substantially affecting the acid content, the process of the invention is suited for recovering a plurality of acids and acid combinations. In some embodiments, the acid to be recovered is a mineral acid. Some non-limiting examples of mineral acids include hydrochloric acid (HCl), nitric acid (HNO 3 ), phosphoric acid (H 3 PO 4 ), sulfuric acid (H 2 SO 4 ), boric acid (H 3 BO 3 ), hydrofluoric acid (HF), hydrobromic acid (HBr) and perchloric acid (HClO 4 ). [0053] In some embodiments, the acid is sulfuric acid (H 2 SO 4 ). In some embodiments, the acid-rich solution containing sulfuric acid is treated with a precursor of a strong oxidizer capable of reacting with an amount of the sulfuric acid in the solution to form a strong oxidizer. In some embodiments, the precursor is hydrogen peroxide. [0054] As stated above, the majority of the organic material contained in the acid-rich solution is removed. Thus, the resulting substantially carbon-free acid solution contains an aqueous acid (e.g. sulfuric acid) solution that contains less than 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.3%, 0.1% by weight of a carbon material. [0055] The amount of the organic material remaining after acid recovery, namely the Total Organic Carbon (TOC) may be determined by a variety of methods, for example: (1) TOC Analyzer, and (2) titration with analytical KMnO 4 . [0056] In some embodiments, the TOC may be measured in parts per million (ppm). In such embodiments, the resulting substantially carbon-free acid solution contains between 0.05 and 900 ppm TOC. In some embodiments, the amount of TOC is between 5 and 900 ppm, between 5 and 500 ppm, between 5 and 300 ppm, between 10 and 900 ppm, between 10 and 500 ppm, between 10 and 300 ppm, between 50 and 900 ppm, between 50 and 500 ppm, between 50 and 300 ppm, between 100 and 900 ppm, between 100 and 500 ppm, between 100 and 300 ppm, between 500 and 1,000 ppm, between 600 and 1,000 ppm, between 700 and 1,000 ppm, between 800 and 1,000 ppm or between 900 and 1,000 ppm. [0057] The carbon material may be any carbonaceous material, i.e., any material containing or composing carbon. The carbonaceous material may be of high molecular weight. [0058] The “organic material”, or “organic matter”, or “carbon materials”, all being used herein interchangeably, is “carbonaceous material”, based on carbon and may or may not be soluble in the acid solution. In some embodiments, the organic matter is insoluble in the acid solution. In some embodiments, the organic matter is fully soluble in the acid solution. In some embodiments, the organic matter is a mixture of such materials, some are soluble and the remaining insoluble in the acid solution. In some embodiments, the organic matter comprises at least 50% insoluble material (in the acid solution). In some embodiments, the organic matter comprises a mixture of soluble and insoluble materials, present in a ratio of 0.001:99.999, respectively (out of the total amount, weight, of the organic matter to be oxidized and removed). In some embodiments, the w/w ratio is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 2:3, 2:5, 2:7, 2:9, 2:11, 11:2, 9:2, 7:2, 5:2, 3:2, respectively. [0059] The organic material may be selected from biological materials, organic materials derived from nature, solvents, and/or organic chemicals used in various industries. In some embodiments, the organic material is selected from natural materials such as hydrocarbons, carbohydrates, proteins, amino acids, lignin, lipid and natural resins. In some embodiments, the carbonaceous material is at least one carbohydrate material. [0060] In some embodiments, the organic material to be oxidized and thereby removed is at least one hydrolysate of plant cellulose material, e.g., as commonly used in the paper industry. In some embodiments, the organic material to be oxidized and thereby removed is at least one carbohydrate or a complex thereof. In some embodiments, the organic material to be oxidized and thereby removed is at least one carbohydrate decomposition product, such as furfural, levulinic acid, hydroxymethylfurfural (HMF), acetic acid, formic acid, monosaccharides such as glucose and xylose and others. [0061] For example, sulfuric acid-containing waste solutions are products of a great variety of processes used in the biomass industry where biomass, such as wood or wood products, is treated with acid to separate out various hydrocarbons, particularly carbohydrates. Cellulose which makes up the major part of plant biomass is greatly used in a variety of industries, particularly in the paper industry, e.g., acid-rich solutions of hydrolyzed cellulose products. [0062] Nano Crystalline Cellulose (NCC) also known as Cellulose Whiskers (CW) and crystalline nanocellulose (CNC), are fibers produced from acid hydrolysis of cellulose, typically being high-purity single crystals of cellulose. Thus, in such processes for the production of NCC large amounts of acid, e.g., sulfuric acid, are used, which may be regenerated as disclosed herein. [0063] Thus, the herein defined acid-rich solution may be a byproduct of a process of NCC production or a byproduct of any chemical process which yields the herein defined acid-rich solution. Thus, in some embodiments, the carbon material is a hemicellulose derivative. In some embodiments, the carbon material is selected from galactose, rhamnose, arabinose, xylose, mannose, cellulose, glucose, hydroxymethylfurfural (HMF), galacturonic acid, lignin derivatives, levulinic acid, cellulose ethers and cellulose esters. [0064] In some embodiments, the carbon material is a carbohydrate, a disaccharide, a monosaccharide, an oligosaccharide or a polysaccharide. [0065] In some embodiments, the concentration of the acid (e.g., sulfuric acid) in the NCC acid-rich solution comprising acid and a carbohydrate is between 1 and 98%, or between 30% and 63%. In other embodiments, the concentration of the acid is between 40% and 63%, between 59% and 63% or is between 60 and 64%. [0066] Thus, the process of the invention may be utilized to purify and collect acid-rich solutions used in the paper industries and may comprise at least one carbohydrate as defined herein, or at least one hemicellulose or derivative thereof, or any of the carbonaceous materials disclosed. [0067] The amount of oxidizer precursor (e.g., hydrogen peroxide) to be added, according to some embodiments, to the acid-rich formulation for enabling in situ synthesis of the strong oxidizer (e.g., Caro's acid) depends of various parameters inter alia reaction time, temperature, carbohydrate concentration, acid:solid ratio, as recognized by the person of skill in the art. In some embodiments, the precursor, e.g., hydrogen peroxide, is added to the acid-rich formulation at a concentration of between about 2 and about 10%. In other embodiments, the amount of the precursor material, e.g., hydrogen peroxide is between 2 and 9%, between 2 and 8%, between 2 and 7%, between 2 and 6%, between 2 and 5%, between 2 and 4%, between 2 and 3%, between 3 and 10%, between 3 and 9%, between 3 and 8%, between 3 and 7%, between 3 and 6%, between 3 and 5%, between 3 and 4%, between 4 and 10%, between 4 and 9%, between 4 and 8%, between 4 and 7%, between 4 and 6%, between 4 and 5%, between 5 and 10%, between 5 and 9%, between 5 and 8%, between 5 and 7%, between 5 and 6%, between 6 and 10%, between 6 and 9%, between 6 and 8%, between 6 and 7%, between 7 and 10%, between 8 and 10%, or between 9 and 10%. [0068] In other embodiments, the amount of precursor material, e.g., hydrogen peroxide, is between 10 and 30%, between 12 and 30%, between 14 and 30%, between 16 and 30%, between 18 and 30%, between 20 and 30%, between 22 and 30%, between 24 and 30%, between 26 and 30%, between 28 and 30%, between 10 and 25%, between 12 and 25%, between 14 and 25%, between 16 and 25%, between 18 and 25%, between 20 and 25%, between 10 and 20%, between 12 and 20%, between 14 and 20%, between 16 and 20%, between 18 and 20%, between 25 and 30%, between 3 and 30%, between 5 and 30%, between 7 and 30% or between 9 and 30%. [0069] In some embodiments, the amount of the precursor material e.g., hydrogen peroxide, or the amount of the oxidizer is not stoichiometric. BRIEF DESCRIPTION OF THE DRAWINGS [0070] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: [0071] FIGS. 1A-C provide a general depiction of carbohydrate decomposition in the presence of a strong oxidizer. [0072] FIG. 1A depicts the carbohydrates produced following hydrolysis of cellulose. [0073] FIG. 1B shows the general decomposition process of carbohydrates. [0074] FIG. 1C shows a suggested mechanism for the oxidation of carbohydrates by H 2 SO 5 (Caro's acid). [0075] FIG. 2 shows the oxidation reaction progress monitored by colorimetric analysis using 5% H 2 O 2 . [0076] FIGS. 3A-B shows the absorbance vs. oxidation time using 3% H 2 O 2 ( FIG. 3A ) and 7.5% H 2 O 2 ( FIG. 3B ) for 0-19 days. [0077] FIG. 4 depicts an example for adsorption of the remaining organic traces and oxidizing agents in the solution using activated carbon. [0078] FIG. 5 describes adsorption of the remaining organic traces and oxidizing agents in the solution using activated carbon over time. DETAILED DESCRIPTION OF EMBODIMENTS [0079] The invention provides a process for separating or recovering acid from acid-rich solutions comprising soluble and/or insoluble organic matter. The cost-effectiveness of the process of the present invention is improved considerably compared to prior art processes as a result of using an oxidizer which is capable of substantially completely oxidizing the organic material while leaving unaffected the acid material, thus not affecting acid losses. Under such a set up, it is possible to carry out the acid recovery at a relatively low temperature, e.g., below 100° C., and from acid solutions containing no less than between 100 and 400 times as much organic contaminants. [0080] An additional advantage of the invention resides in the fact that no, or only little, undesired by-products, such as soluble oxidized organic materials are formed. These too may be removed by further processing of the acid solution. Example 1: Process of Recovering Acid from Acid-Rich Formulations [0081] 7.54 kg of 30% H 2 O 2 (5% of H 2 O 2 weight per weight final solution) were loaded at R.T to 38 kg ˜60% sulfuric acid suspension containing 2.2% carbohydrates (weight per solution weight). The composition of the suspension was around 2/3 of insoluble complex carbohydrates (e.g. cellulose, hemicellulose) and ⅓ soluble carbohydrates (monomeric+polymeric) and their derivatives. Such an acid formulation contained glucose (9.8 g/L-30 g/L), galactose (<0.2 g/L), arabinose (<0.2 g/L), mannose (<0.2 g/L), xylose (0.6 g/L-1.8 g/L), formic acid (<1 g/L), acetic acid (<1 g/L), levulinic acid (<1 g/L), hydroxymethylfurfural (HMF) (<0.2 g/L) and furfural (<0.2 g/L). [0082] The reaction mixture was stirred at R.T until it exothermed or was refluxed)(110°-130° and monitored by spectrophotometer. After 90 minutes the absorption in the region 400 nm-1100 nm reached a minimum, indicating that the majority of the organic material was oxidized. Thereafter, the reaction was cooled down. After 90 minutes, the solution was completely clear. [0083] The thus-obtained cleared acid formulation was basically free of organic matter, or contained very minute amounts of organic matter. To further purify the acid formulation, the following steps were optionally carried out. [0084] 0.76 kg of activated carbon (2% of Activated carbon weight per weight of initial 60% acid) were loaded at R.T to a “cleared solution” of 44 kg ˜50% sulfuric acid solution containing traces of carbohydrates and ˜5% H 2 O 2 . The solution was mixed and monitored by spectrophotometer and TOC levels measured by titration with KMnO 4 . After 8 h the absorption in the region 400 nm-1100 nm and the titer amount reached minimum and the reaction was cooled down and filtered. The “cleaned solution” was thereafter used in further acid-based reactions. Example 2: General Process of Recovering Acid from Acid-Rich Formulations from NCC Production Processes [0085] The above process was also used for acid recovery of acid formulations used in industrial process for utilizing paper products, paper pulp or generally cellulose materials. [0086] The general sequence of process steps is exemplifies herein by acid recovery from an acid-rich solution which is an end-solution in the production of NCC. The process of the invention may comprise: Step 1. Separation of concentrated sulfuric acid from the hydrolyzed NCC suspension; and Step 2. Decomposition of carbohydrates contained in the sulfuric acid solution by the addition of hydrogen peroxide. The oxidized products may thereafter be removed by a multitude of additional steps or ways. [0089] The process of the present invention may further comprise additional steps as follows: Step 1. Separation of concentrated sulfuric acid from the hydrolyzed NCC suspension; Step 2. Decomposition of carbohydrates contained in the sulfuric acid solution by the addition of hydrogen peroxide; Step 3. Decomposition of the remaining oxidizing agents by different methods such as UV, activated carbon etc.; and Step 4. Optionally, adsorption of the remaining organic traces in the solution using an adsorbent such as activated carbon. [0094] In a process conducted according to the invention, implementing steps 1, 2 and optionally steps 3 and 4, and in order to maximize recovery of the sulfuric acid, a controlled hydrolysis of cellulose fibers was further carried out. [0095] The conditions for the acid hydrolysis used to extract the crystalline particles from a variety of cellulose sources was very narrow (e.g., acid concentration, reaction time, temperature, acid:solid ratio). It is commonly known that during at the end of the hydrolysis, during NCC production, the mixture is typically diluted with water to quench the reaction, and only then the mixture undergoes a series of separation and washing (centrifugation or filtration). The more the acid is diluted, the less cost effective its recovery. Thus, the present invention renders such dilution steps unnecessary, and thus cost-effective. Example 3: Process of Recovering Acid from Acid-Rich Formulations from NCC Production Processes Step 1: Separation of Concentrated Acid [0096] Following separation of concentrated sulfuric acid from the hydrolyzed NCC suspension, the high majority of the reaction mixture weight was obtained in the supernatant in the first separation. This “used solution” contained nearly all of the acid originally used in the reaction for making the NCC, along with soluble carbohydrates. [0097] The NCC was precipitated with some of the acid originally put in. Step 2: Decomposition of Carbohydrates in Sulfuric Acid Solution by Hydrogen Peroxide [0098] The “used solution” contained a variety of carbohydrates. The composition of the “used solution” depended on the cellulosic raw material and on the hydrolysis conditions. FIG. 1A shows the carbohydrates produced from the hydrolysis of cellulose. For a solution that also contained other saccharides such as xylose, mannose and other hemicellulose derivatives, similar products were depicted. FIG. 1B shows the general decomposition process of the carbohydrates. [0099] The addition of hydrogen peroxide to sulfuric acid results in the formation of Caro's Acid or Piranha solution. A suggested mechanism for the oxidation of the carbohydrates by Caro's acid is provided in FIG. 1C which demonstrates how the organic matter is converted to carbon dioxide. [0100] 7.54 kg of 30% H 2 O 2 (5% of H 2 O 2 weight per weight final solution) were loaded at R.T to a “used solution” of 38 kg ˜60% sulfuric acid solution containing 2.6% carbohydrates (weight per solution weight). The oxidation reaction of the sulfuric acid solution was carried out five days after separation of the hydrolysis mixture (step 1). The reaction mixture was then refluxed)(110°-130° and monitored by spectrophotometer. After 90 minutes the absorption in the region 400 nm-1100 nm reached a minimum ( FIG. 2 ), indicating that the majority of the organic material was oxidized. Thereafter, the reaction was cooled down. The color reduction could be seen with time. After 90 minutes, the solution was completely clear. [0101] As FIGS. 3A-B show, for a given carbohydrate concentration, the optimal oxidation time was 90 minutes up to 6 days from the day of hydrolysis and first separation (i.e., step 1). Prolonged periods required longer oxidation times. However, complete oxidation and full recovery of acid was always possible. The optimal minimum percentage of hydrogen peroxide required for oxidizing the organic matter, depended on the carbohydrate concentration in the sulfuric acid solution. FIG. 4 shows that for a 2.6% concentration, 5% H 2 O 2 was optimal for some solutions since it enabled the same performance of 7.5% with less dilution of the acid. Step 3 (and Step 4): Adsorption of the Remaining Organic Traces and Oxidizing Agents in the Solution Using Activated Carbon. [0102] This optional step(s) in the recovery process has two objectives: [0103] A. Removal of organic traces that remained after step 2; [0104] B. Removal of oxidizer. [0105] 0.76 kg of activated carbon (2% of Activated carbon weight per weight of initial 60% acid) were loaded at R.T to a “cleared solution” of 44 kg ˜50% sulfuric acid solution containing traces of carbohydrates and ˜5% H 2 O 2 . The solution was mixed and monitored by spectrophotometer and TOC levels measured by titration with KMnO 4 . After 8 h the absorption in the region 400 nm-1100 nm and the titer amount reached minimum ( FIG. 5 ) and the reaction was cooled down and filtered. The “cleaned solution” was thereafter used in further acid-based reactions.

Provided is an unique, efficient and cost-effective process for the recovery of acid from acid-rich solutions. The process of the subject matter utilizes a strong oxidizer, such as Caro's acid, to disintegrate or render insoluble organic or inorganic materials such as carbohydrates and complexes thereof contained in acid-rich solutions, to make efficient and simple the separation and recovery of the acid solution. The acid recovered thus obtained is free of organic matter, and containing nearly all of the acid originally contained in the acid-rich solution.

FIELD OF THE INVENTION [0001] The field of this invention relates to techniques and equipment to gravel-pack and treat closely spaced zones and more particularly in applications where some degree of isolation is desired between the zones for accommodating different treatment plans. BACKGROUND OF THE INVENTION [0002] In producing hydrocarbons or the like from loose or unconsolidated and/or fractured formations, it is not uncommon to produce large volumes of particulate material along with the formation fluids. As is well known in the art, these particulates routinely cause a variety of problems and must be controlled in order for production to be economical. A popular technique used for controlling the production of particulates (e.g., sand) from a well is one which is commonly known as “gravel-packing.” [0003] In a typical gravel-packed completion, a screen is lowered into the wellbore on a work string and is positioned adjacent to the subterranean formation to be completed, e.g., a production formation. Particulate material, collectively referred to as “gravel,” and a carrier fluid is then pumped as a slurry down the work string where it exits through a “cross-over” into the well annulus formed between the screen and the well casing or open hole, as the case may be. The carrier liquid in the slurry normally flows into the formation through casing perforations, which, in turn, is sized to prevent flow of gravel therethrough. This results in the gravel being deposited or “screened out” in the well annulus where it collects to form a gravel pack around the screen. The gravel, in turn, is sized so that it forms a permeable mass, which allows the flow of the produced fluids therethrough and into the screen while blocking the flow of the particulates produced with the production fluids. [0004] One major problem that occurs in gravel-packing single zones, particularly where they are long or inclined, arises from the difficulty in distributing the gravel over the entire completion interval, i.e., completely packing the entire length of the well annulus around the screen. This poor distribution of gravel (i.e., incomplete packing of the interval) is often caused by the carrier fluid in the gravel slurry being lost into the more permeable portions of the formation, which, in turn, causes the gravel to form “sand bridges” in the annulus before all the gravel has been placed. Such bridges block further flow of slurry through the annulus, which prevents the placement of sufficient gravel (a) below the bridge in top-to-bottom packing operations or (b) above the bridge in bottom-to-top packing operations. [0005] To address this specific problem, “alternate path” well strings have been developed which provide for distribution of gravel throughout the entire completion interval, even if sand bridges form before all the gravel has been placed. Some examples of such screens include U.S. Pat. Nos.: 4,945,991; 5,082,052; 5,113,935; 5,417,284; 5,419,394; 5,476,143; 5,341,880; and 5,515,915. In these well screens, the alternate paths (e.g., perforated shunts or bypass conduits) extend along the length of the screen and are in fluid communication with the gravel slurry as the slurry enters the well annulus around the screen. If a sand bridge forms in the annulus, the slurry is still free to flow through the conduits and out into the annulus through the perforations in the conduits to complete the filling of the annulus above and/or below the sand bridge. [0006] One of the problems with the alternate path design is the relatively small size of the passages through them. These tubes are also subject to being crimped or otherwise damaged during the installation of the screen. Thus, several designs in the past have placed these tubes inside the outer surface of the screen. This type of design substantially increases the cost of the screen over commercially available screens. Yet other designs have recognized that it is more economical to place such tubes on the outsides of the screen and have attempted to put yet another shroud over the alternate paths which are on the outside of the screen to prevent them from being damaged during insertion or removal. Such a design is revealed in U.K application No. GB 2317 630 A. [0007] While such designs can be of some benefit in a bridging situation, they present difficulties in attempting to treat and gravel-pack zones which are fairly close together. Many times zones are so close together that traditional isolation devices between the zones cannot be practically employed because the spacing is too short. For example, situations occur where an upper and lower zone are spaced only 5-20 feet from each other, thus precluding a complete completion assembly in between screens for each of the zones. When these closely spaced zones are encountered, it is desirable to be able to gravel-pack and treat the formations at the same time so as to save rig time by eliminating numerous trips into the well. This method was explained in U.S. Pat. No. 6,230,803. At times these types of completions will also require some degree of isolation between them, while at the same time producing one or the other of the formations. In U.S. Pat. No. 6,230,803 a method was disclosed to facilitate fluid treatments such as fracture stimulation, as well as gravel packing, simultaneously, in two or more adjacent producing zones, while providing limited hydraulic isolation between two or more adjacent zones. That method minimized rig time for the completion by reducing the number of trips required to install the gravel screen assemblies and to treat the formation. The limitation of that method was that the two zones had to be treated simultaneously. This caused problems if the nature of the adjacent formations necessitated a different treatment program. The isolation of the zones after completion was also less than ideal. Accordingly, the present method seeks to allow the treatment of adjacent zones in a single trip one at a time so that different regimens can be used. It provides, in the preferred embodiment, a check valve for retention of fluids in the string against loss into the formation. It provides an option of isolating a zone while treating the other. The method of the present invention can also be used in a single producing zone to minimize bridging problems during gravel distribution by splitting the zone into segments and gravel packing each segment individually. These objectives and how they are accomplished will become clearer to those skilled in the art from a review of the detailed description of the preferred embodiment and the claims, which appear below. SUMMARY OF THE INVENTION [0008] A method is disclosed that allows for sequential treatment of two zones in a single trip while isolating the zones. A fluid loss valve prevents the column of fluid in the tubing from flowing into the lower formation until activated. Zone isolation is accomplished by manipulation of a port on a wash pipe attached to the crossover assembly. BRIEF DESCRIPTION OF THE DRAWINGS [0009] [0009]FIG. 1 is a section view of the equipment in place and the upper zone being treated while the lower zone is isolated; [0010] [0010]FIG. 2 is the view of FIG. 1 with the lower zone being treated; [0011] [0011]FIG. 3 shows both zones treated; [0012] [0012]FIG. 4 is an enlargement of the fluid loss prevention valve in the assembly; [0013] [0013]FIG. 5 is a detailed view of the wash pipe in position to allow treatment of the upper zone; and [0014] [0014]FIG. 6 is the view of FIG. 5 showing the wash pipe positioned for squeezing the lower zone. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0015] [0015]FIG. 1 shows a wellbore 10 and zones 12 and 14 to be treated. The preferred embodiment illustrates the method for two zones but those skilled in the art will appreciate that additional zones can be treated in a single trip with duplication of the equipment shown for doing two zones in one trip, as will be explained below. A tubular string 16 is used to run in a known crossover tool 18 , which is movable with respect to packer 20 after it is set. In FIG. 1, the packer 20 is shown in the set position and the crossover is set up to circulate to deposit gravel outside of screen 22 and adjacent the perforations 24 of zone 12 . Arrows 26 show the gravel and fluid mixture coming from the surface through the string 16 and going through the packer 20 . The gravel and fluid stream indicated by arrows 26 goes through crossover 18 and through ports 28 in the crossover tool 18 . Sliding sleeve valve 30 is left in the open position during run in so that the ports 32 are open for the gravel and fluid stream 26 to pass into annulus 34 . The stream passes through the screen 22 leaving the gravel in annulus 34 and the fluid to pass through the screen 22 into annular space 36 around the wash pipe 38 . Wash pipe 38 has several openings 40 which are shown in FIG. 1 as above seal 42 . Seal 42 keeps clean fluid from going down around the outside of the wash pipe 38 . Any fluid 26 that gets into the wash pipe 38 through openings 40 is stopped from exiting the lower end of the wash pipe 38 by a ball 44 pushed by the flow against a seat 46 . Return flow 26 passes through passage 48 lifting ball 50 off seat 52 . The return flow passes through passage 54 in crossover 18 and up to the surface via annulus 56 above the set packer 20 . A flapper 58 is held open by wash pipe 38 . When the wash pipe 38 is removed, the flapper 58 closes to prevent the column of fluid from the surface inside the string 16 from flowing into the formation and potentially causing damage. [0016] Packer 60 is supported by screen 22 and it in turn supports screen 62 at perforations 64 . Packer 60 is multi-bore. The first bore 66 communicates to inside screen 62 . The second bore 68 communicates with a standpipe 70 that is capped at cap 72 at its upper end. As shown in FIG. 1 gravel is deposited around the outside of standpipe 70 and standpipe 70 extends above perforations 24 . After the zone 12 is fully treated, including gravel packing and other operations that may be needed like acidizing, pressure on cap 72 can be raised to break it to provide access to zone 14 through bore 68 . Cap 72 can be a rupture disc or any other type of barrier that can be removed in any number of ways among them pressure, chemical reaction or some applied force. As shown in FIG. 2, the gravel and fluid stream 74 passes through standpipe 70 and bore 68 in packer 60 to lodge in annulus 76 adjacent perforations 64 . Returns pass through screen 62 and into wash pipe 38 to displace ball 44 off of seat 46 . Ports 40 in wash pipe 38 are now below seal 42 . This position of ports 40 effectively isolates zone 12 from returns. The returns 74 pass through passage 48 and return to the surface through annulus 56 in the manner previously described for zone 12 . Thus, although the gravel packing is done from top to bottom, each zone is independent and bridging in zone 12 has no effect on the deposition of gravel in zone 14 . [0017] [0017]FIG. 3 shows the crossover 18 and wash pipe 38 removed. The flapper 58 has slammed shut to prevent fluid loss to either zone 12 or 14 . Sliding sleeve 30 has been pushed closed by the removal of the wash pipe 38 . [0018] [0018]FIG. 5 shows the isolation of the lower zone 14 when treating the upper zone 12 by virtue of having openings 40 above seal 42 . Seal 42 seals around the outside of wash pipe 38 and ball 44 on seat 46 prevents returns from treating the zone 12 from reaching zone 14 . Additionally, bore 68 is closed at this time by cap 72 on standpipe 70 . FIG. 6 shows how zone 12 is isolated when treating zone 14 . Here the returns lift ball 44 off of seat 46 . Ports 40 are now below seal 42 forcing all returns to bypass zone 12 and rise to the crossover 18 . It should be noted that the cross-over 18 can be configured to close access to surface annulus 56 , in which case the gravel packing or acid treating or any other procedure will be without returns or by bull heading into the formation. [0019] [0019]FIG. 4 simply illustrates the flapper 58 held open by the wash pipe 38 . It slams shut as soon as the wash pipe 38 is removed. [0020] Those skilled in the art will appreciate that the zones can be closely spaced and can be treated separately in a single trip. Two or more zones can be sequentially treated in a single trip. The treatment can be by circulation with returns to the surface or elsewhere or without returns with the fluids driven into the formation being treated. When treating two zones, one is isolated when the other is treated. Finally, a fluid loss prevention feature, which is a flapper 58 in the preferred embodiment retains the liquid column in the tubular 16 and prevents its passage into the formation. The fluid prevention feature can be a flapper or ball device or any other valve that hold up the liquid column when the wash pipe 38 is pulled out. [0021] The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:

A method is disclosed that allows for sequential treatment of two zones in a single trip while isolating the zones. A fluid loss valve prevents the column of fluid in the tubing from flowing into the lower formation until activated. Zone isolation is accomplished by manipulation of a port on a wash pipe attached to the crossover assembly.

RELATED APPLICATIONS [0001] This application claims the benefit under 35 USC §119(e) to U.S. Provisional Application No. 62/006,556, filed on Jun. 2, 2014, the contents of which are hereby incorporated by reference in their entirety. FIELD OF THE INVENTION [0002] This invention relates to a system and method for modeling physical phenomena such as internal conditions and/or boundary conditions, as for example to model or determine fluid flows in, around and/or across objects or structures and, in particular, a system and method which operates to provide a numerical solution of partial differential equations (PDEs). BACKGROUND OF THE INVENTION [0003] Computer methods and algorithms which use partial differential equations to analyze and solve complex systems involving various forms of fluid dynamics having input boundary conditions are known. Computer modeling may allow a user to simulate the flow of air and other gases over an object or model the flow of fluid through a pipe. Computational fluid dynamics (CFD) is often used with high-speed computers to simulate the interaction of one or more fluids over a surface of an object defined by certain boundary conditions. Typical methods involve large systems of equations and complex computer modeling and include traditional finite difference methodology, cell-centered finite volume methodology and vertex-centered finite volume methodology, as for example are described in the inventors commonly owned U.S. patent application Ser. No. 14/207,027, filed Mar. 12, 2014, the disclosure of which is hereby incorporated in its entirety. [0004] Current computer modeling schemes have proven limited in the form of objects they can model and require different models and algorithms for different continuum mechanics applications, such as between compressible and non-compressible fluids and deformable solids. SUMMARY OF THE INVENTION [0005] The present invention provides for method and system for determining and/or modeling physical phenomena with internal conditions and/or boundary conditions, as for example, to determine or compute heat conduction and/or heat convection within fluid dynamics of compressible and/or non-compressible fluids around objects. In one particular embodiment, it is an object of this invention to provide a method and system which for example, includes a processor, a display or monitor and programme instructions operable to compute fluid flow over or through objects. In one possible embodiment, the system may be used to compute fluid flow over aircraft components, such as airflow over aircraft wings, fuselage, landing gear, pylons and the like. [0006] Preferably, the present system is operable to provide and display as a visual output a numerical or calculated solution to a physical phenomenon such as heat conduction or fluid flow in either bounded domains such as piping systems bounded by walls, human or animal arteries and the like; as well as unbounded solution domains, where for example, free air or liquid flows past an object. [0007] In another embodiment, the invention provides a method and system for computing and outputting as data, graphics, or other display and/or monitor, fluid dynamics of non-compressible liquids within a pipe or transport mechanisms, as for example, through static and/or movable valves, or other components which are described with other boundary conditions. [0008] The present invention further may provide a system and method for modeling physical phenomena such as internal fluid flows with boundary conditions of both bounded domains and unbounded domains. More preferably, the system provides for a numerical solution of partial differential equations (PDEs) which comprise a pre-processing component, a processing component and a post-processing component. [0009] The system preferably includes a processor and memory or other suitable input means for receiving a Cartesian mesh model of a bounded or unbounded domain or object, defined as a plurality of active, inactive and boundary nodes encompassing the domain and/or object. The processor may operate in conjunction with programme instructions for implementing the steps of discretizing a partial differential equation based on a stencil associated with each node in the mesh by (i) selecting an active node, (ii) identifying the stencil associated with the selected node, (iii) mapping the stencil from the physical domain to a generic uniform computational stencil, (iv) applying finite difference formulas on the computational stencil to approximate the partial differential equation by a finite difference equation, (v) solving the finite difference equation to obtain an approximate value for the solution at the selected node, (vi) repeating the above steps for all active nodes in the mesh, (vii) checking the iteration process for convergence, (viii) repeating the above steps (i)-(vii) if the solution has not converged, or (ix) terminating the iteration process if the solution has converged, and (x) printing all calculated data to an output file. [0010] More preferably, where the system operates to provide PDE models of a physical phenomenon occurring in a bounded domain, such as an internal fluid flow of liquid or air flow within a target object, such as piping or other passage bounded by walls, air flow in an automobile passenger compartment, flow in a pump, blood flow through arteries, or heat conduction in a solid object. A geometric, and preferably rectangular box (rectangle in 2-dimensional modeling; cube in 3-dimensional modeling) and preferably a Cartesian mesh is object-fitted wherein the mesh is superimposed or placed around the object domain, touching the domain at its extreme endpoints. [0011] Where the system operates to provide PDE models of phenomenon occurring in unbounded solution domains, such as external fluid flow or air flow over a target object, such as an aircraft or aircraft component structures such as wings, fuselage, pylon, landing gear, etc., air flow through wind turbines, and/or river flow around bridge piers, the system operates to generate both an object-fitted internal mesh or box superimposed around the object(s), as well as a larger surrounding outer reference mesh or reference box having its sides spaced away from object-fitted mesh and the object(s) inside. [0012] In yet a further alternate embodiment, the system and method provide for analysis and modeling of combinations of dynamic internal and external flows, such as air flow around moving road vehicles, and air flow around an aircraft during take-off or landing, and wherein the system processor is operable to generate superimposed boxes which provide mesh-structures for the solution domain using Cartesian cut-stencil based methods of finite difference solutions of PDEs. [0013] In one preferred method, a two-dimensional Cartesian mesh for a 2D bounded object or solution domain is generated by the system processor. The computer program stored in computer memory is operated to determine the active and inactive nodes in the mesh, as well as coordinates of the boundary nodes, namely the points where the mesh lines intersect with the boundary of the solution domain. Most preferably, the computer program also includes programme instructions to identify the neighbouring nodes for each node, and to record the neighbouring node coordinates or location, such that each node P has associated with it a “stencil” centered at P, with a node identifier (i.e. such as active, inactive, boundary) and in the case where a two-dimensional mesh is generated, a set of 4 (in 2D) neighbour nodes to the west (w), south (s), east (e) and north (n). [0014] In a three-dimensional mesh, a set of 6 (in 3D) neighbour nodes are generated, including further nodes front (f) and back (b). [0015] If all nodes on the stencil are indicated as active nodes, then the stencil does not touch the boundary of the domain and the stencil is described as “regular” or “uncut”. If the node P is adjacent to the boundary, then at least one of its neighbour nodes is identified or recognized as being a boundary node. Preferably, the program includes instructions to determine if the boundary node lies at the intersection of a mesh horizontal grid line and a vertical grid line and if so the node is identified as a “regular” boundary node, or otherwise the node is indicated as an “irregular” boundary node. [0016] Most preferably, for each boundary node, whether regular or irregular, the computer also includes stored program instructions operational to calculate and record an outward unit normal vector to the boundary. [0017] Accordingly, in one aspect, the present invention resides in a computer-implemented method for approximating partial differential equations for determining fluid flow of compressible and non-compressible liquids. The method comprising of a plurality of nodes; for each node P in the plurality of nodes: (i) locating all neighbouring nodes in the Cartesian mesh that are attached directly to the node P (4 neighbouring nodes in 2D, 6 neighbouring nodes in 3D); (ii) grouping all of the neighbouring nodes to form one stencil having a central vertex at node P; (iii) mapping the said stencil from the physical domain to a generic uniform computational stencil; (iv) approximating the transformed partial differential equation(s) at the vertex of the stencil centered at node P using difference formulas to obtain the finite difference equation(s). [0018] In another aspect, the present invention resides in a system for determining a physical phenomenon in relation to an object, and wherein the physical phenomenon is selected as being modelable by partial differential equations; input means for receiving a model of the object, the model defining the object as being contained within the Cartesian mesh comprising a plurality of active nodes, inactive nodes and boundary nodes; a processor coupled to a memory, the processor configured for implementing the steps of A. initializing an expected solution at each said active node; B. obtaining an approximate solution of a partial differential equation based on a stencil for each said active node by: i) selecting a first said active node, ii) identifying and mapping the stencil associated with the selected node to a generic uniform computational stencil, the computational stencil being characterized by an equal node spacing in each direction, iii) applying a finite difference formula at the selected node on the computational stencil to approximate the partial differential equation at the selected node by a finite difference equation, iv) solving the finite difference equation to obtain an approximate value of a calculated solution at the selected active node, and v) selecting a next active node, and repeating steps B (ii) to (iv) for each remaining said active mesh nodes. C. comparing the calculated solution to the expected solution for each said active node to determine convergence, and where convergence is determined, outputting the solution. [0027] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, wherein the processor further is configured whereby where convergence is not determined, select the calculated solution as a new expected solution for each said active node, and repeating steps B and C until convergence is determined. [0028] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein the physical phenomenon comprises a fluid flow within the object; said active nodes comprise coordinates of intersecting mesh lines within the object; said inactive nodes comprise coordinates of intersecting mesh lines outside the object; and said boundary nodes comprise coordinates of intersection of mesh lines and object boundary lines. [0029] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein the physical phenomenon comprises a heat transfer within the object; said active nodes comprise coordinates of intersecting mesh lines within the object; said inactive nodes comprise coordinates of intersecting mesh lines outside the object; and said boundary nodes comprise coordinates of intersection of mesh lines and object boundary lines. [0030] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein said physical phenomenon comprises a fluid flow about the object; said active nodes comprise coordinates of intersecting mesh lines outside the object; said inactive nodes comprise coordinates of intersecting mesh lines within the object; and said boundary nodes comprise coordinates of intersection of mesh lines and object boundary lines. [0031] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein the input means is for receiving a reference boundary surrounding and spaced a distance from the object, wherein the active nodes comprise intersecting mesh line nodes outside the object and within the reference boundary. [0032] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein said Cartesian mesh comprises a uniform object-fitted Cartesian grid. [0033] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein the Cartesian mesh is selected as a non-uniformly spaced object-fitted grid, wherein the mesh spacing is selectively biased by proximity to object boundary lines. [0034] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein the step of solving comprises, wherein if each neighboring node is an active node, assigning the solution at each neighboring node as the expected solution. [0035] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein the step of solving comprises, wherein if each neighboring node is an active node, assigning the solution at each neighboring node as the expected solution. [0036] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein the step of solving further comprises, if a said neighboring node is a boundary node, assigning the solution at the boundary node as a known boundary value. [0037] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein the step of approximating the partial differential equation comprises approximating the partial differential equation at the common vertex of the stencil centered at the selected node using finite difference formulas. [0038] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein physical phenomenon is one dimensional, and the step of mapping the stencil comprises: [0039] applying mapping of the selected active node P at coordinate x P and next adjacent neighbour nodes at coordinates x W , x E in accordance with formula (1). [0000] x=a 2 ξ 2 +a 1 ξ+a 0   (1) where a 2 =(x W −2x P +x E )/2=x″/2 a 1 =(x E −x W )/2=x′ a 0 =x P [0044] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein the physical phenomenon is two dimensional, and the step of mapping the stencil comprises: [0045] applying mapping of the selected active node P at coordinates (x P , y P ) and next adjacent neighbor nodes at coordinates (x W , y W ), (x E , y E ), (x S , y S ), (x N , y N ) in accordance with formula (2): [0000] x=a 2 ξ 2 +a 1 ξ+a 0 [0000] y=b 2 η 2 +b 1 η+b 0   (2) where a 2 =(x W −2x P +x E )/2=x″/2 b 2 =(y S −2y P +y N )/2=y″/2 a 1 =(x E −x W )/2=x′ b 1 =(y N −y S )2=y′ a 0 =x P b 0 =y P [0050] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein the physical phenomenon is three dimensional, and the step of mapping the stencil comprises: [0000] applying mapping of the selected node P at coordinates (x P , y P , z P ) and next adjacent neighbor nodes at coordinates (x W , y W , z W ), (x E , y E , z E ), (x S , y S , z S ), (x N , y N , z N ), (x F , y F , z F ), (x B , y B , z B ) in accordance with formula (3): [0000] x=a 2 ξ 2 =a 1 ξ+a 0 [0000] y=b 2 η 2 =b 1 η+b 0 [0000] z=c 2 ζ 2 +c 1 ζ+c 0   (3) where a 2 =(x W −2x P +x E )/2=x″/2 b 2 =(y S −2y P +y N )/2=y″/2 c 2 =(z F −2z P +z B )/2=z″/2 a 1 =(x E −x W )/2=x′ b 1 =(y N −y S )/2=y′ c 1 =(z B −z F )/2=z′ a 0 =x P b 0 =y P c 0 =z P [0057] In another aspect, the invention resides in a system in accordance with any of the foregoing aspects, further wherein the output solution is provided independently of mesh cell flux, mesh cell area and/or mesh cell boundary calculation. [0058] Further and other features of the invention will be apparent to those skilled in the art from the following detailed description of the embodiments thereof. BRIEF DESCRIPTION OF THE DRAWINGS [0059] Reference may now be had to the following detailed description taken together with the accompanying drawings, in which: [0060] FIG. 1 shows schematically a system for modeling flow dynamics or other physical phenomena using a computer system in accordance with a preferred embodiment of the present invention; [0061] FIG. 2 illustrates graphically, the identification of solution domains using the computer of FIG. 1 in modeling both the internal flow in bounded domains and the external flow in unbounded domains in accordance with a preferred method; [0062] FIG. 3 illustrates graphically the computer generation of a Cartesian mesh in a two-dimension bounded solution domain, and the identification of inactive, active and boundary nodes, generated for predicting internal flow in accordance with a preferred embodiment; [0063] FIG. 4 illustrates schematically the mapping of a general two-dimensional stencil associated with Cartesian mesh nodes shown in FIG. 3 , to a generic uniform computational stencil; [0064] FIGS. 5 and 6 illustrate the cut-stencil mapping for a one-dimensional non-uniform cut stencil with arms of arbitrary length, and for an interval containing many non-uniform one-dimensional stencils; [0065] FIG. 7 illustrates schematically the application of an iterative algorithm for time-dependent ordinary differential equation resulting from the discretization of the partial differential equation(s); [0066] FIGS. 8 to 10 illustrate graphically sample data outputs using the cut-stencil method of the current invention; [0067] FIG. 11 illustrates the formulation of a fourth-order solution scheme using the cut-stencil approach of the present invention; [0068] FIG. 12 shows graphically data output solutions obtained using second-order and fourth-order formulation schemes using the current invention, in comparison to an exact solution; [0069] FIG. 13 illustrates graphically determined local truncation errors using second-order and fourth-order formulation schemes of the current invention; [0070] FIGS. 14 and 15 illustrates graphically the results of an adaptive mesh procedure developed based on local truncation error calculations in accordance with the present invention; and [0071] FIG. 16 gives a 2D illustration of the essential difference between the use of cut stencils, which is the subject of this invention, and cut cells which are used in Finite Volume and Finite Element methods. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0072] FIG. 1 illustrates schematically a system 10 for determining or the predicted modelling of compressible and non-compressible fluids in accordance with a preferred embodiment of the invention. The system 10 includes a computer which includes main memory 25 , read only memory 26 , and storage memory 27 . A bus 12 provides electronic communication between the main memory 25 ROM, 26 and storage memory 27 , and the computer processor 16 and I/O board 14 . [0073] The I/O board 14 communicates via a suitable data connector 18 with the user operable keyboard 23 , video display 24 and cursor control 22 . In addition secondary communication output 21 may also be provided. The processor 16 stores computer program instructions which in operation of the system 10 are adapted to provide and output to a user a graphic and/or data output on the display 24 , which simulates fluid flow dynamics through and/or around physical boundary defining target object 30 (see for example FIG. 2 ). [0074] As will be described, in use of the system 10 , the user enters into the computer memory 25 object modeling parameters such as computer aided design (CAD) model of the target object 30 , boundary conditions and/or fluid properties or conditions by way of the key board 23 , PDA or other suitable input 18 . Optionally the modeling parameters may be displayed on the video display 24 in the manner shown in FIG. 2 . [0075] Preferred objects 30 to be modeled with the system 10 may include without limitation both two-dimensional or three-dimensional bounded structures such as pipes, arteries, and the like; as well as two-dimensional or three-dimensional unbounded domains such as external structures, river beds and the like. The system 10 may thus be used to model external and internal fluid or air flow around buildings, road vehicles or aircraft components, as well as flow along pipes. In an alternate embodiment, the present system 10 may also be used to predict and/or model heat flow or heat conduction through objects and/or liquids. [0076] The system 10 of the present invention provides for the numerical solution of partial differential equations (PDEs) which comprises pre-processing, processing and post-processing components. [0077] FIG. 2 shows a sample finite rectangular domain 32 used in the PDE modelling of a two-dimensional bounded domain system for the object 30 . In particular, the computer processor 16 operates to generate and superimpose a rectangular box 32 around the selected solution domain or domain of interest for the object 30 . The generated box 32 has a dimension selected to contact or touch the selected domain of interest on multiple sides, and preferably at each of its top, bottom and extreme endpoints. [0078] FIG. 3 shows the construction of a Cartesian mesh 50 for a 2D bounded solution domain. The computer processor 16 includes computer program having stored instructions operational to determine the active and inactive nodes 52 , 54 in the mesh 50 , as well as the coordinates of the boundary nodes 56 , namely, points where the mesh lines intersect with the boundary of the domain of interest. Most preferably, the computer program also identifies the neighbouring nodes for each node and records their coordinates (location). In this way, each node P has associated with it a “stencil” centered at P, with a node ID or identifier (active, inactive, boundary) and a set of 4 (in 2D) neighbour nodes to the west (W), south (S), east (E) and north (N), as for example are shown in FIG. 4 . [0079] If all nodes on the stencil are active nodes, then the stencil does not touch the boundary of the domain and the stencil is described as “regular” or “uncut.” If the node P is adjacent to the boundary, then at least one of its neighbours will be a boundary node. If the boundary node lies at the intersection of a horizontal grid line and a vertical grid line, the node is called a “regular” boundary node, otherwise it is an “irregular” boundary node. [0080] For all boundary nodes, whether regular or irregular, the computer program also calculates and records the outward unit normal vector to the boundary. [0081] In the above described construction of a Cartesian mesh, the mesh intersection with a domain boundary and identification of nodes may further form a basis for the Cartesian “cut-cell” and the “embedded mesh” technologies used with Finite Volume and Finite Element codes. However, unlike conventional methods where the discretization of the PDE is based on the geometry and connectivity of the cells in the mesh, Finite Difference discretization is used in the current invention based on the stencil associated with each node in the mesh. [0082] The inventor has further appreciated that cut-cell and embedded mesh formulations may require the computation and storage of a large amount of additional information, such as the unit normal vectors along all edges (2D) or faces (3D) of all cells (interior and cut), cell connectivity (in 2D each cell has 8 connected cells, 4 of them share an edge with the central cell, 4 share a point with the central cell), area (2D) or volume (3D) of each cell, length of each cell edge (2D) or surface area of each face (3D). In contrast, however, this additional information is not needed for the present cut-stencil method. [0083] FIGS. 4 to 6 illustrate graphically the essence of the cut-stencil method in accordance with a preferred embodiment. The general idea of mapping any stencil (stencil arms may be equal or of different lengths) to a generic uniform unit stencil (arms all have unit length) is shown graphically in FIG. 4 . The unique mapping that accomplishes this goal is given in FIG. 5 for the ID case, and is representative of the mappings used in both 2D and 3D application. FIG. 6 demonstrates a feature of the stencil mapping, and in particular, that each individual triplet of adjacent nodes has its own unique quadratic mapping to the uniform computational stencil. Focusing on the stencil as an entity and mapping it to a uniform computational stencil advantageously allows the treatment of cut stencils in the same way as regular stencils, allowing for a Finite Difference discretization of the PDE on any domain, irrespective of its complexity. [0084] It is noted that coordinate mappings are also sometimes used in numerical solutions of PDEs. Such mappings are, however, defined by mathematical functions that maps all logically connected nodes in the physical domain into a set of evenly distributed nodes in a computational domain. As such, the use of a single mapping function limits the ability to deal with highly complex domains. [0085] The general one-dimensional convection-diffusion equation often used by researchers to test their numerical formulations and solution algorithms is as follows: [0000] ∂ ϕ ∂ t  | P  - Γ  [ 1 x P ′ 2  ∂ 2  ϕ ∂ ξ 2  | P  - x P ″ x P ′ 3  ∂ ϕ ∂ ξ  | P ] + u x P ′  ∂ ϕ ∂ ξ  | P = S p [0086] The equation shown above is the 1D version, but extensions to 2D and 3D are straightforward and understood. Transformation of the convection-diffusion equation to the computational stencil centered at node P is illustrated as follows: [0087] Convection-Diffusion equation at node P transforms to [0000] ∂ ϕ ∂ t - Γ  ∂ 2  ϕ ∂ x 2 + u  ∂ ϕ ∂ x = S [0088] The time-dependent ordinary differential equation resulting from space discretization of the above equation is shown in FIG. 7 , and an iterative algorithm is given for the steady (time-independent) case. [0089] FIGS. 8 to 10 illustrate examples of calculations using the cut-stencil methodology in accordance with the present invention, and demonstrate graphically the strength and capabilities of the current system. [0090] The cut-stencil approach is a convenient framework from which to develop high-order solution schemes. Formulation of the 4 th -order scheme is illustrated graphically in FIG. 11 . A comparison between the 4 th -order, 2 nd -order and exact solutions are shown in FIG. 12 . [0091] Two important features of the cut-stencil method should be noted: 1) from a formulation perspective, one can easily devise 8 th -order, 16 th -order and higher-order schemes. 2) Secondly, there is no loss of accuracy at nodes adjacent to the boundary since they are treated in the same way as interior nodes. This is a significant improvement over all existing methods which use a high-order scheme at interior nodes, but must use a lower-order scheme at the boundary, thereby degrading the overall accuracy of the solution. [0092] Formulae for the local truncation errors (LTE) are easily derived in a Finite Difference approach. For the Finite Volume and Finite Element approaches, researchers have developed error estimates, but these serve only as approximations to the true error. Using the Taylor series expansion at node P in the discretized equation gives the modified differential equation, which provides an expression of the leading terms in the local truncation error (LTE), e.g., for steady convection-diffusion. Local truncation errors for second and fourth order schemes may be estimated as follows: [0000] 2 nd  -  order   scheme L . T . E . = R 2   x P ′   2  ϕ P  ξ 2 - x P ″ 6   x P ′3   3  ϕ P  ξ 3 - R 6  x P ′   3  ϕ P  ξ 3 + 1 12  x P ′2   4  ϕ P  ξ 2 4 th  -  order   scheme L . T . E . = 1 1440  x P ′2   6  ϕ P  ξ 6 - R 768   x P ′   6  ϕ P   ξ 6 +  x P ″ 480   x P ′3   5  ϕ P   ξ 5 - 7  R 960  x P ′   5  ϕ P  ξ 5 - R 32  x P ′   4  ϕ P  ξ 4 + R 12  x P ′   3  ϕ P  ξ 3 [0093] FIG. 13 shows graphically the LTE by means of the aforementioned formula, and illustrates one use of the LTE, to compare the accuracy of schemes of different orders. The table shown in FIG. 13 suggests that a prescribed level of accuracy can be achieved with much fewer nodes in a 4 th -order scheme (i.e. 40 cells) compared to a 2 nd -order scheme (i.e. 400 cells), i.e. a ratio of 1 to 10. Some 2D tests have shown that the ratio may be even more dramatic, at 1 to 100. This is significant since a typical industrial simulation may require 20,000,000 nodes or more for a 2 nd -order scheme (some researchers are using more than 1 billion nodes). Such computations are very expensive, requiring large computing resources, 1000's of CPU hours and long run times. The higher-order schemes based on the cut-stencil approach have the potential to reduce these calculations, thereby reducing demands on computer resources and shortening run times. [0094] The cut-stencil method is ideally suited for mesh adapting. FIGS. 14 and 15 show graphically the results of an adaptive mesh procedure that has been developed based on the LTE. Existing adaptive mesh methods are generally based on error estimates or solution gradients, which are not as predictive of the mesh region requiring adapting as the LTE is. [0095] FIG. 16 shows graphically an application of the cut-stencil method in 2D. The domain shown in FIG. 16 cannot be solved by traditional finite difference, due to the cut stencils around the boundary. As illustrated with reference to FIG. 16 , the domain can be solved using Finite Volume or Finite Element, but the solution procedures are much more complicated than the cut-stencil method. [0096] The solution provided by the present invention shows promising results with reduced relative errors and processing requirements, as for example the solution of the problem shown in FIG. 16 , as reflected in the following Table 1: [0000] TABLE 1 Relative Error (N = 242) %(Rel. %(Rel. Boundary error) Avg. at error) Max. at Equation condition internal nodes internal nodes Diffusion Dirichlet 0.021% 0.040% (all) Diffusion Neumann 0.023% 0.041% (West & South) Diff.- Conv. Dirichlet 0.012% 0.031% (central) (all) Diff.- Conv. Neumann 0.013% 0.030% (central ) (West & South) Diff.- Conv. Dirichlet 0.345% 0.873% (central/upwind) (all) [0097] Although the detailed description describes and illustrates various preferred embodiments and methods, the invention is not strictly limited to the best mode of the invention which is described. Variations and modifications will now occur to persons skilled in the art. For a definition of the invention, reference may be had to the appended claims.

A system includes a processor with stored instructions for generating a Cartesian mesh model of a bounded or unbounded object domain. The model includes active, inactive and boundary nodes which encompass the domain. The processor effects of discretizing a partial differential equation based on a stencil associated with each active node in the mesh by (i) selecting an active node, (ii) identifying the stencil associated with the selected node, (iii) mapping the stencil from the physical domain to a generic uniform computational stencil, (iv) applying finite difference formulas on the computational stencil to approximate the partial differential equation by a finite difference equation, (v) solving the finite difference equation to obtain an approximate value for the solution, and thereafter (vi) checking the iteration process for convergence. If the solution has not converged, the system repeats the aforementioned steps, or terminates the iteration process if the solution has converged, and outputs to a user the calculated data file.

RELATED APPLICATIONS This application is a continuation of co-pending U.S. patent application Ser. No. 12/622,871, filed on Nov. 20, 2009, which is a continuation of co-pending U.S. patent application Ser. No. 10/813,229, filed Mar. 31, 2004, now U.S. Pat. No. 7,660,822, the disclosures of which are hereby incorporated by reference herein. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to information searching systems and, more particularly, to systems and methods for sorting and displaying searches of aggregated information in multiple dimensions. 2. Description of Related Art Existing information searching systems use search queries to search through aggregated data to retrieve specific information that corresponds to the received search queries. Such information searching systems may search information stored locally, or in distributed locations. The World Wide Web (“web”) is one example of information stored in distributed locations. The web contains a vast amount of information and locating a desired portion of that information, however, can be challenging. This problem is compounded because the amount of information on the web and the number of new users inexperienced at web searching are growing rapidly. Search engines attempt to return hyperlinks to web documents in which a user is interested. Generally, search engines base their determination of the user's interest on search terms (called a search query) entered by the user. The goal of the search engine is to provide links to high quality, relevant results to the user based on the search query. Typically, the search engine accomplishes this by matching the terms in the search query to a corpus of pre-stored web documents. Web documents that contain the user's search terms are “hits” and are returned to the user. The search engine oftentimes ranks the documents using a ranking function based on the documents' perceived relevance to the user's search terms. In addition to determining relevance, existing search paradigms may use other dominant characteristics to sort the results of a search. For example, in shopping or product search (e.g., Froogle), users typically like to sort by price. As another example, when searching news stories or USENET/groups, users typically prefer to sort by date or recency. As a further example, when searching images, users may prefer to sort by image quality or image size. As yet another example, in geographic search, users may prefer to sort by distance. With existing search paradigms, users must choose to sort either by relevance or by the alternative characteristic, and can at best toggle between these modes. This creates a frustrating experience for the user in which important sorting dimensions are ignored (e.g., the user retrieves a lot of very cheap products that aren't what they wanted, or the user gets a lot of very recent articles that are not really about the topic they wanted). Existing search paradigms employed in any type of information searching system, thus, make it very difficult for users to easily find reasonably relevant data while, at the same time, also optimizing at least one other desired characteristic. Accordingly, it would be desirable to implement a search paradigm in an information searching system that permits sorting and display of search results by multiple alternative characteristics. SUMMARY OF THE INVENTION Systems and methods, consistent with the principles of the invention, implement a search paradigm that permits users to search and sort data according to multiple characteristics. Such characteristics may include relevance or another alternative characteristic, such as, for example, price, date, recency, image quality, image size, or geographic distance. Consistent with the principles of the invention, results of a search that sorts by multiple characteristics may be displayed in a document that plots the results of the search in a multi-dimensional graph, with each dimension of the graph corresponding to one of the multiple characteristics. According to one aspect consistent with the principles of the invention, a method of displaying the results of a search is provided. The method includes receiving one or more search queries. The method further includes searching stored data based on the one or more search queries to generate results, where the results are orderable by at least one search characteristic. The method also includes providing a document that includes a multi-dimensional graph of the results of the search, where at least one dimension of the multi-dimensional graph corresponds to the at least one search characteristic. According to another aspect, a method of plotting results of a data search is provided. The method includes executing one or more search queries to search stored data. The method further includes receiving results of the executed one or more search queries, where the results are orderable by at least one search characteristic. The method also includes designating a visual representation for each of the results and plotting each of the visual representations on a multi-dimensional graphical display, where at least one dimension of the multi-dimensional graphical display corresponds to the at least one search characteristic. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, explain the invention. In the drawings, FIG. 1 is a diagram of an overview of an exemplary implementation of the invention; FIG. 2 is a diagram of an exemplary network in which systems and methods consistent with the principles of the invention may be implemented; FIG. 3 is an exemplary diagram of a client and/or server of FIGS. 1 & 2 in an implementation consistent with the principles of the invention; FIGS. 4A and 4B are flowcharts of exemplary processing for providing multi-dimensional display documents according to an implementation consistent with the principles of the invention; FIG. 5 is a diagram of an exemplary news search document according to an implementation consistent with the principles of the invention; FIG. 6 is a diagram of an exemplary product search document according to an implementation consistent with the principles of the invention; FIG. 7 is a diagram of an exemplary two-dimensional display document according to an implementation consistent with the principles of the invention; FIG. 8 is a diagram of an exemplary document with news links according to an implementation consistent with the principles of the invention; and FIG. 9 is a diagram of an exemplary news document according to an implementation consistent with the principles of the invention. DETAILED DESCRIPTION The following detailed description of the invention refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements. Also, the following detailed description does not limit the invention. Systems and methods consistent with the principles of the invention implement a search paradigm that permits users to search and sort data according to multiple characteristics, such as, for example, relevance, price, date, recency, image quality, image size, or geographic distance. The results of the search may be plotted on a multi-dimensional graph, with each dimension of the graph corresponding to one of the multiple characteristics. A “document,” as the term is used herein is to be broadly interpreted to include any machine-readable and machine-storable work product. A document may include an e-mail, a web site, a file, a combination of files, one or more files with embedded links to other files, a news group posting, a blog, a web advertisement, etc. In the context of the Internet, a common document is a web page. Web pages often include textual information and may include embedded information (such as meta information, images, hyperlinks, etc.) and/or embedded instructions (such as Javascript, etc.). Exemplary System Overview FIG. 1 illustrates a system overview of one exemplary implementation of the invention. As shown in FIG. 1 , a server 120 may receive one or more data search queries 130 from a client 110 via, for example, a network (not shown). The one or more data search queries 130 may be explicitly provided by a user at the client 110 , or may, for example, be inferred from the user's past “web browsing” activity. The one or more search queries may be derived in any manner, such as, for example, user selection from a list of related search queries, user selection from a list of “canned” queries, etc. Server 120 may perform a search of aggregated data using the received one or more data search queries. The aggregated data may include data retrieved and aggregated from one or more data sources, such as, for example, news sources, image sources, product sources, or any other type of data source. Server 120 may sort the results of the search using multiple characteristics derived, at least in part, from the received one or more data search queries. For example, in one implementation, server 120 may sort the results of the search based on relevance and one other characteristic, such as, for example, price, data, recency, image quality, image size, or geographic distance. In other implementations, server 120 may sort the results of the search based on multiple characteristics, such as any combination of three or more of the above noted characteristics. Using the results of the search and sort, server 120 may then provide a multi-dimensional display document 140 to client 110 . Multi-dimensional display document 140 may plot the results of the search with each of the multiple characteristics, used to sort the results of the search, being represented as a dimension on the plot. For example, if document 140 includes a two-dimensional plot, then one dimension may be relevance, and another dimension may be price. Multi-dimensional display document 140 may include any number of dimensions (e.g., 2, 3, 4, etc.). Exemplary Network Configuration FIG. 2 is an exemplary diagram of a network 200 in which systems and methods consistent with the principles of the invention may be implemented. Network 200 may include multiple clients 110 connected to multiple servers 120 and 210 via a network 220 . Network 220 may include a local area network (LAN), a wide area network (WAN), a telephone network, such as the Public Switched Telephone Network (PSTN), an intranet, the Internet, a memory device, another type of network, or a combination of networks. Two clients 110 and two servers 120 and 210 have been illustrated as connected to network 220 for simplicity. In practice, there may be more or fewer clients and servers. Also, in some instances, a client may perform the functions of a server and a server may perform the functions of a client. Clients 110 may include client entities. An entity may be defined as a device, such as a wireless telephone, a personal computer, a personal digital assistant (PDA), a laptop, or another type of computation or communication device, a thread or process running on one of these devices, and/or an object executable by one of these devices. Servers 120 and 210 may include server entities that gather, process, search, and/or maintain documents in a manner consistent with the principles of the invention. Clients 110 and servers 120 and 210 may connect to network 220 via wired, wireless, and/or optical connections. In an implementation consistent with the principles of the invention, server 120 may include a search engine 225 usable by users at clients 110 . Server 120 may implement a data aggregation service by crawling a corpus of documents (e.g., web pages) hosted on data source server(s) 210 and store information associated with these documents in a repository of crawled documents. The data aggregation service may be implemented in other ways, such as by agreement with the operator(s) of data source server(s) 210 to distribute their hosted documents via the data aggregation service. Server 120 may additionally provide multi-dimensional plots of data retrieved based on one or more search queries provided by users at clients 110 . Each dimension of a multi-dimensional plot may correspond to a characteristic of the one or more search queries used to sort the searched data. Server(s) 210 may store or maintain documents that may be crawled by server 120 . Such documents may include data related to published news stories, products, images, user groups, geographic areas, or any other type of data. For example, server(s) 210 may store or maintain news stories from any type of news source, such as, for example, the Washington Post, the New York Times, Time magazine, or Newsweek. As another example, server(s) 210 may store or maintain data related to specific product data, such as product data provided by one or more product manufacturers. While servers 120 and 210 are shown as separate entities, it may be possible for one or more of servers 120 and 210 to perform one or more of the functions of another one or more of servers 120 and 210 . For example, it may be possible that two or more of servers 120 and 210 are implemented as a single server. It may also be possible for a single one of servers 120 or 210 to be implemented as two or more separate (and possibly distributed) devices. Exemplary Client/Server Architecture FIG. 3 is an exemplary diagram of a client or server entity (hereinafter called “client/server entity”), which may correspond to one or more of clients 110 and servers 120 and 210 , according to an implementation consistent with the principles of the invention. The client/server entity may include a bus 310 , a processing unit 320 , an optional main memory 330 , a read only memory (ROM) 340 , a storage device 350 , one or more input devices 360 , one or more output devices 370 , and a communication interface 380 . Bus 310 may include one or more conductors that permit communication among the components of the client/server entity. Processing unit 320 may include any type of software, firmware or hardware implemented processing device, such as, a microprocessor, a field programmable gate array (FPGA), combinational logic, etc. Main memory 330 may include a random access memory (RAM) or another type of dynamic storage device that stores information and instructions for execution by processing unit 320 , if processing unit 320 includes a microprocessor. ROM 340 may include a conventional ROM device or another type of static storage device that stores static information and/or instructions for use by processing unit 320 . Storage device 350 may include a magnetic and/or optical recording medium and its corresponding drive. Input device(s) 360 may include one or more conventional mechanisms that permit an operator to input information to the client/server entity, such as a keyboard, a mouse, a pen, voice recognition and/or biometric mechanisms, etc. Output device(s) 370 may include one or more conventional mechanisms that output information to the operator, including a display, a printer, a speaker, etc. Communication interface 380 may include any transceiver-like mechanism that enables the client/server entity to communicate with other devices and/or systems. For example, communication interface 380 may include mechanisms for communicating with another device or system via a network, such as network 220 . As will be described in detail below, the client/server entity, consistent with the principles of the invention, performs certain searching-related operations. The client/server entity may, in some implementations, perform these operations in response to processing unit 320 executing software instructions contained in a computer-readable medium, such as memory 330 . A computer-readable medium may be defined as one or more physical or logical memory devices and/or carrier waves. The software instructions may be read into memory 330 from another computer-readable medium, such as data storage device 350 , or from another device via communication interface 380 . The software instructions contained in memory 330 may cause processing unit 320 to perform processes that will be described later. Alternatively, hardwired circuitry may be used in place of, or in combination with, software instructions to implement processes consistent with the principles of the invention. Thus, implementations consistent with the principles of the invention are not limited to any specific combination of hardware circuitry and software. Exemplary Processing FIGS. 4A and 4B are flowcharts of exemplary processing for providing multi-dimensional display documents according to an implementation consistent with the principles of the invention. As one skilled in the art will appreciate, the processing exemplified by FIGS. 4A and 4B can be implemented in software and stored on a computer-readable memory, such as main memory 330 , ROM 340 or storage device 350 of server 120 . In other implementations, the processing exemplified by FIGS. 4A and 4B can be implemented in hardwired circuitry, such as combinational logic, within processing unit 320 of server 120 . Processing may begin with server 120 accessing external data sources (e.g., from server(s) 210 ), fetching the data content stored at the data sources and aggregating the fetched data content in a local memory (act 405 ) ( FIG. 4A ). For example, server 120 may use a web crawler (e.g., web robot) that may access documents hosted by data source server(s) 210 . Data source server(s) 130 may host, for example, data content related to news, products, images, user groups, or other types of data content. The fetched data content may then be indexed and grouped, using conventional indexing and grouping algorithms (act 410 ). Server 120 may then receive one or more search queries from a user at client 110 (act 415 ). Server 120 may support various types of search queries, such as, for example, searches by price, date, recency, image quality, image size or distance. In one implementation, server 120 may use one or more search queries derived in any type of manner. For example, any type of “clickable” query may be used by server 120 . Such “clickable” queries may, include, for example, selections from a list of related queries or selections from categories of queries. In another implementation, search queries entered by the user in the past may be ranked based on recency and frequency and made accessible through a menu placed on a search page for selection by the user. Selecting such a search query may reissue the search query. In a further implementation, one or more search queries may be inferred from the user's current or past browsing activity (e.g., a data search query may include an inferred set of keywords, etc.). Additionally, any combination of the above search queries may be supported by server 120 . In one implementation of the invention directed to news searching (e.g., Google News), as shown in FIG. 5 , a user may enter search text in a news search page 500 . News search page 500 may include various search features that permit the user to specify customized search parameters. News search page 500 may support search query forms such as (a) one or more keywords (e.g., ‘with all of the words,’ ‘with the exact phrase,’ ‘with at least one of the words,’ ‘without the words’) (b) topical categories (e.g., ‘topic=sports,’ ‘topic=crime’; (c) geographical categories (e.g., ‘geo=Asia,’ ‘geo=USA’); (d) geographical reporting areas (e.g., U.S. newspapers, European newspapers, etc.); (e) restrictions on the news sources to be considered (e.g., ‘return only articles from the news sources named,’ ‘do not return articles from the new source named’); and/or (g) a time window that defines a start and end of a time interval from which articles may be retrieved. A search query may additionally include any combination of the above forms of search query. In another implementation of the invention directed to product searching, as shown in FIG. 6 , a user may enter search text in a product search page 600 . Product search page 600 may include various search features that permit the user to specify customized search parameters. Product search page 600 may support search query forms such as (a) one or more keywords (e.g., ‘with all of the words,’ ‘with the exact phrase,’ ‘with at least one of the words,’ ‘without the words’); (b) a product price range (e.g., ‘display products whose price is between’); (c) a specification of where the one or more keywords should occur (e.g., ‘in the product name or description,’ ‘in the product description’); (d) a product category (e.g., ‘return products from the category’); (e) a specification of whether to group by store (e.g., ‘group by store,’ ‘show all products’); (f) a view selection (e.g., ‘list view,’ ‘grid view,’ ‘graph view’); and/or (g) a time window that defines a start and end of a time interval from which product data may be retrieved. A search query may additionally include any combination of the above forms of search query. Server 120 may then store the one or more search queries in local memory (e.g., main memory 330 , ROM 340 or storage device 350 ) (act 420 ). Server 120 , using search engine 225 , may execute the one or more search queries (act 425 ). The results of the executed search queries may be sorted using existing sorting techniques. Such sorting techniques may, for example, sort the results of the executed search queries by relevance. The sorting techniques may further sort the results of the executed search queries by one or more additional characteristics, such as, for example, price, date, recency, image quality, image size, geographic distance, etc. The sorted results of the one or more search queries may be provided to the user as a multi-dimensional display document (act 430 ) ( FIG. 4B ). The multi-dimensional display document may include a multi-dimensional graph of the sorted results of the one or more search queries, where each dimension of the graph corresponds to a characteristic of the executed search. For example, each dimension of the multi-dimensional display may correspond to one of relevance, price, date, recency, image quality, image size, geographic distance or any other appropriate search characteristic. Each search query result may be represented by small summaries, such as, for example, a small thumbnail image, an icon, or a fragment of text (e.g., a single word or short phrase). Since any form of summary may take up non-zero area in the plot of the multi-dimensional display, not all search results may be able to be displayed simultaneously on a single display document. In such a case, the plot may span across multiple pages of the document (i.e., a user may “page” from one page of the document to the next to view all of the results). In some implementations of the invention, the size of each of the summaries of the results may vary (e.g., more relevant equals a bigger icon or image). Because results may not be points on the plot, two results may overlap if centered about their true points. Therefore, consistent with the invention, the results may not have to be positioned exactly on the multi-dimensional plot. Results plotted on a dimension corresponding to relevance, in particular, may have their position shifted to a significant extent along the relevance dimension. So long as the relative ordering along the different dimensions is substantially preserved, some liberties may be taken in order to plot more results on the multi-dimensional display document. Optimal packing to preserve certain constraints of minimizing out-of-position-ness may likely be NP-hard. However, several simple greedy solutions may be possible to shift result positions slightly to fit more results in the multi-dimensional display document, and to make sure that whatever results are displayed may not be too far from their correct positions. In some implementations, for example, most relevant to least relevant results may be positioned accurately, but if there is overlap with a prior result, then results may be “shifted” in the less relevant direction until there is no overlap. Or, alternatively, an overlapping ‘more relevant’ result can be shifted up or down on the other axis up X % of the size of the thumbnails if it will prevent an overlap. However, this shift should be performed only if it also preserves the relative ordering along the other dimension with all currently positioned results. In one implementation, a fixed number of results may be positioned per “page” of the multi-dimensional display document. For example, each “page” may include the N most relevant results, or the N most relevant results and the M results that optimize another dimension (e.g., 10 most relevant and 10 cheapest in price). Displaying the N most relevant results, and the M results that optimize another dimension, provides advantage over a simple list because it simultaneously shows the relevance of the results and the ordering of the results in at least one other dimension. In another implementation, the particular overlaps on the plot might determine what results get displayed (e.g., continue including more results until there is room for no more, or until a threshold on number or relevance is passed). In yet another implementation, more relevant results may be permitted to overlap on top of less relevant results, but the amount of overlap may be permitted to increase only as relevance decreases, so that from the more relevant side of the plot to the less relevant side there is a sort of “fanning-out” with more and more results able to “peek out” from under their “neighbors.” Consistent with some implementations of the invention, natural restrictions may be performed on the range of one or more of the dimensions of the multi-dimensional display document (e.g., price restrictions, date restrictions). Restriction on the range of one or more of the dimensions may be achieved by implementing multiple (e.g., 2, 3, or 4) overlapping ranges that have different granularities (e.g., prices in $100 increments and prices in $20 increments). The user may implement a restriction (e.g., by “clicking” on a range if using a mouse interface) that “zooms” the display in, causing the selected range to “zoom” out to fill substantially the entire display of the multi-dimensional document. In a further implementation, the axes of the plot on the multi-dimensional display document may be scaled. The axes, thus, need not be linear, and any monotonic transformation of an axis may be used (e.g., a logarithmic scale for price or recency). In some instances, if a large gap between clusters of results exists, a monotonic “squeezing” of the space between the results could be used to bring them closer together and fit more results into the plot with less blank space (e.g., a simple piecewise linear transformation could be used that simply uses a different linear scaling for the gap between two clusters of results). This might be useful if the set of results plotted includes the top N results that optimize each axis independently. In another implementation, the multi-dimensional display document may plot multiple dimensions, with none of the dimensions being relevance (e.g., price vs. merchant rating, image quality vs. staleness, date vs. poster reputation, etc.). FIG. 7 illustrates an exemplary two-dimensional display document 700 consistent with one implementation of the invention. Two-dimensional display document 700 depicts a “graph view” of the results of a product search related to ‘digital cameras’ where the y-axis corresponds to ‘price’ and the x-axis corresponds to ‘relevance.’ If the user is using a “mouse,” moving the mouse over a target in the multi-dimensional display document (e.g., a thumbnail image, icon, etc.) may trigger the display of additional information. For example, in the product searching context, thumbnails with no text might be used to represent each product result and, upon “mouse-over” of a particular thumbnail, the title, exact price, and merchant for the offer might be displayed. Another possible representation for product searching might be a thumbnail image with a single word or phrase displayed in close association with the image (e.g., inside of, on top of, or in close proximity to). In certain subdomains (e.g., product categories), domain-specific summaries may be used. For example, in electronics domains, for queries that return many different models, the model number/string may be an appropriate one word label. For a digital camera query, thumbnails of digital cameras may appear with labels such as “S400,” “A70,” “G3,” etc. Accessories may be labeled with the word that describes the category of accessory (e.g., ‘battery,’ ‘case,’ ‘book,’ etc.). The accessory offers could be classified as accessories by price clustering or other classification signals and classified into the domain specific accessory types by another simple classifier. Upon “mouse-over” of the word or phrase, additional information may be displayed. Server 120 may determine whether a user selects a result from the multi-dimensional display document (act 435 ). In one implementation, for example, the user may select a result by “clicking” on an associated image, icon, or text, with a mouse. If the user selects a result from the provided multi-dimensional display document, then server 120 may provide a document(s) that corresponds to the selected result (act 440 ). For example, FIG. 9 illustrates an exemplary news document 900 that includes a news story 905 that corresponds to a specific selection by a user. According to another exemplary aspect, server 120 may, upon selection of a result, provide a document with one or more links to documents that correspond to the selected result. For example, FIG. 8 illustrates an exemplary document 800 that includes multiple links 805 corresponding to a news story related to a news search query provided by a user. If the user selects one of the one or more links of the provided document, then server 120 may provide a document(s) that corresponds to the selected link. For example, FIG. 9 illustrates an exemplary news document 900 that includes a news story 905 that corresponds to a specific link selected by a user. Returning to act 435 , if the user does not select a result from the multi-dimensional display document, then server 120 may determine whether the user selects a “next page” or a restricted range of the multi-dimensional display document (act 445 ). More results may exist then can fit on one page of the multi-dimensional display document, therefore, the user may select a subsequent page to view additional results. The user may further select a restricted range (e.g., by “clicking” on a range if using a mouse interface) to “zoom” the display in, causing the selected range to “zoom” out to substantially fill the entire display of the multi-dimensional display document. Server 120 may provide the selected “next page,” or the restricted range, of the multi-dimensional display document to the user (act 450 ). If the user does not select a “next page” or a restricted range, then processing may return to act 415 , with receipt of another search query(ies) from the user. CONCLUSION Systems and methods consistent with the principles of the invention enable the sorting of search results by multiple different characteristics, and display of those search results on a multi-dimensional graph. Each dimension of the multi-dimensional graph may correspond to one of the multiple characteristics. The foregoing description of preferred embodiments of the present invention provides illustration and description, but is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. For example, while a series of acts have been described with regard to FIGS. 4A and 4B , the order of the acts may be modified in other implementations consistent with the principles of the invention. Additionally, while aspects of the invention has been described with respect to searching information stored in the world-wide web (WWW), one skilled in the art will recognize that the sorting and displaying of search results in multiple dimensions, consistent with the principles of the invention, may be employed in any other type of information searching system. Also, non-dependent acts may be performed in parallel. It will also be apparent to one of ordinary skill in the art that aspects of the invention, as described above, may be implemented in many different forms of software, firmware, and hardware in the implementations illustrated in the figures. The actual software code or specialized control hardware used to implement aspects consistent with the principles of the invention is not limiting of the present invention. Thus, the operation and behavior of the aspects of the invention were described without reference to the specific software code—it being understood that one of ordinary skill in the art would be able to design software and control hardware to implement the aspects based on the description herein. Further, certain portions of the invention have been described as “logic” that performs one or more functions. This logic may include hardware, such as an application specific integrated circuit or a field programmable gate array, software, or a combination of hardware and software. The scope of the invention is defined by the following claims and their equivalents.

A system plots results of a data search. The system executes one or more search queries to search stored data. The system receives results of the executed one or more search queries, where the results are orderable by at least one search characteristic. The system designates a visual representation for each of the results. The system plots each of the visual representations on a multi-dimensional graphical display, where at least one dimension of the multi-dimensional graphical display corresponds to the at least one search characteristic.

[0001] This invention relates to a process and apparatus for the separation of a gas containing hydrocarbons. The applicants claim the benefits under Title 35, United States Code, Section 119(e) of prior U.S. Provisional Application No. 61/186,361 which was filed on Jun. 11, 2009. The applicants also claim the benefits under Title 35, United States Code, Section 120 as a continuation-in-part of U.S. patent application Ser. No. 12/689,616 which was filed on Jan. 19, 2010, and as a continuation-in-part of U.S. patent application Ser. No. 12/372,604 which was filed on Feb. 17, 2009. Assignees S.M.E. Products LP and Ortloff Engineers, Ltd. were parties to a joint research agreement that was in effect before the invention of this application was made. BACKGROUND OF THE INVENTION [0002] Ethylene, ethane, propylene, propane, and/or heavier hydrocarbons can be recovered from a variety of gases, such as natural gas, refinery gas, and synthetic gas streams obtained from other hydrocarbon materials such as coal, crude oil, naphtha, oil shale, tar sands, and lignite. Natural gas usually has a major proportion of methane and ethane, i.e., methane and ethane together comprise at least 50 mole percent of the gas. The gas also contains relatively lesser amounts of heavier hydrocarbons such as propane, butanes, pentanes, and the like, as well as hydrogen, nitrogen, carbon dioxide, and other gases. [0003] The present invention is generally concerned with the recovery of ethylene, ethane, propylene, propane, and heavier hydrocarbons from such gas streams. A typical analysis of a gas stream to be processed in accordance with this invention would be, in approximate mole percent, 90.3% methane, 4.0% ethane and other C 2 components, 1.7% propane and other C 3 components, 0.3% iso-butane, 0.5% normal butane, and 0.8% pentanes plus, with the balance made up of nitrogen and carbon dioxide. Sulfur containing gases are also sometimes present. [0004] The historically cyclic fluctuations in the prices of both natural gas and its natural gas liquid (NGL) constituents have at times reduced the incremental value of ethane, ethylene, propane, propylene, and heavier components as liquid products. This has resulted in a demand for processes that can provide more efficient recoveries of these products and for processes that can provide efficient recoveries with lower capital investment. Available processes for separating these materials include those based upon cooling and refrigeration of gas, oil absorption, and refrigerated oil absorption. Additionally, cryogenic processes have become popular because of the availability of economical equipment that produces power while simultaneously expanding and extracting heat from the gas being processed. Depending upon the pressure of the gas source, the richness (ethane, ethylene, and heavier hydrocarbons content) of the gas, and the desired end products, each of these processes or a combination thereof may be employed. [0005] The cryogenic expansion process is now generally preferred for natural gas liquids recovery because it provides maximum simplicity with ease of startup, operating flexibility, good efficiency, safety, and good reliability. U.S. Pat. Nos. 3,292,380; 4,061,481; 4,140,504; 4,157,904; 4,171,964; 4,185,978; 4,251,249; 4,278,457; 4,519,824; 4,617,039; 4,687,499; 4,689,063; 4,690,702; 4,854,955; 4,869,740; 4,889,545; 5,275,005; 5,555,748; 5,566,554; 5,568,737; 5,771,712;5,799,507; 5,881,569; 5,890,378; 5,983,664; 6,182,469; 6,578,379; 6,712,880; 6,915,662; 7,191,617; 7,219,513; reissue U.S. Pat. No. 33,408; and co-pending application Ser. Nos. 11/430,412; 11/839,693; 11/971,491; and 12/206,230 describe relevant processes (although the description of the present invention in some cases is based on different processing conditions than those described in the cited U.S. patents). [0006] In a typical cryogenic expansion recovery process, a feed gas stream under pressure is cooled by heat exchange with other streams of the process and/or external sources of refrigeration such as a propane compression-refrigeration system. As the gas is cooled, liquids may be condensed and collected in one or more separators as high-pressure liquids containing some of the desired C 2 + components. Depending on the richness of the gas and the amount of liquids formed, the high-pressure liquids may be expanded to a lower pressure and fractionated. The vaporization occurring during expansion of the liquids results in further cooling of the stream. Under some conditions, pre-cooling the high pressure liquids prior to the expansion may be desirable in order to further lower the temperature resulting from the expansion. The expanded stream, comprising a mixture of liquid and vapor, is fractionated in a distillation (demethanizer or deethanizer) column. In the column, the expansion cooled stream(s) is (are) distilled to separate residual methane, nitrogen, and other volatile gases as overhead vapor from the desired C 2 components, C 3 components, and heavier hydrocarbon components as bottom liquid product, or to separate residual methane, C 2 components, nitrogen, and other volatile gases as overhead vapor from the desired C 3 components and heavier hydrocarbon components as bottom liquid product. [0007] If the feed gas is not totally condensed (typically it is not), the vapor remaining from the partial condensation can be split into two streams. One portion of the vapor is passed through a work expansion machine or engine, or an expansion valve, to a lower pressure at which additional liquids are condensed as a result of further cooling of the stream. The pressure after expansion is essentially the same as the pressure at which the distillation column is operated. The combined vapor-liquid phases resulting from the expansion are supplied as feed to the column. [0008] The remaining portion of the vapor is cooled to substantial condensation by heat exchange with other process streams, e.g., the cold fractionation tower overhead. Some or all of the high-pressure liquid may be combined with this vapor portion prior to cooling. The resulting cooled stream is then expanded through an appropriate expansion device, such as an expansion valve, to the pressure at which the demethanizer is operated. During expansion, a portion of the liquid will vaporize, resulting in cooling of the total stream. The flash expanded stream is then supplied as top feed to the demethanizer. Typically, the vapor portion of the flash expanded stream and the demethanizer overhead vapor combine in an upper separator section in the fractionation tower as residual methane product gas. Alternatively, the cooled and expanded stream may be supplied to a separator to provide vapor and liquid streams. The vapor is combined with the tower overhead and the liquid is supplied to the column as a top column feed. [0009] In the ideal operation of such a separation process, the residue gas leaving the process will contain substantially all of the methane in the feed gas with essentially none of the heavier hydrocarbon components and the bottoms fraction leaving the demethanizer will contain substantially all of the heavier hydrocarbon components with essentially no methane or more volatile components. In practice, however, this ideal situation is not obtained because the conventional demethanizer is operated largely as a stripping column. The methane product of the process, therefore, typically comprises vapors leaving the top fractionation stage of the column, together with vapors not subjected to any rectification step. Considerable losses of C 2 , C 3 , and C 4 + components occur because the top liquid feed contains substantial quantities of these components and heavier hydrocarbon components, resulting in corresponding equilibrium quantities of C 2 components, C 3 components, C 4 components, and heavier hydrocarbon components in the vapors leaving the top fractionation stage of the demethanizer. The loss of these desirable components could be significantly reduced if the rising vapors could be brought into contact with a significant quantity of liquid (reflux) capable of absorbing the C 2 components, C 3 components, C 4 components, and heavier hydrocarbon components from the vapors. [0010] In recent years, the preferred processes for hydrocarbon separation use an upper absorber section to provide additional rectification of the rising vapors. The source of the reflux stream for the upper rectification section is typically a recycled stream of residue gas supplied under pressure. The recycled residue gas stream is usually cooled to substantial condensation by heat exchange with other process streams, e.g., the cold fractionation tower overhead. The resulting substantially condensed stream is then expanded through an appropriate expansion device, such as an expansion valve, to the pressure at which the demethanizer is operated. During expansion, a portion of the liquid will usually vaporize, resulting in cooling of the total stream. The flash expanded stream is then supplied as top feed to the demethanizer. Typically, the vapor portion of the expanded stream and the demethanizer overhead vapor combine in an upper separator section in the fractionation tower as residual methane product gas. Alternatively, the cooled and expanded stream may be supplied to a separator to provide vapor and liquid streams, so that thereafter the vapor is combined with the tower overhead and the liquid is supplied to the column as a top column feed. Typical process schemes of this type are disclosed in U.S. Pat. Nos. 4,889,545; 5,568,737; and 5,881,569, co-pending application Ser. Nos. 11/430,412 and 11/971,491, and in Mowrey, E. Ross, “Efficient, High Recovery of Liquids from Natural Gas Utilizing a High Pressure Absorber”, Proceedings of the Eighty-First Annual Convention of the Gas Processors Association, Dallas, Tex., Mar. 11-13, 2002. [0011] The present invention employs a novel means of performing the various steps described above more efficiently and using fewer pieces of equipment. This is accomplished by combining what heretofore have been individual equipment items into a common housing, thereby reducing the plot space required for the processing plant and reducing the capital cost of the facility. Surprisingly, applicants have found that the more compact arrangement also significantly reduces the power consumption required to achieve a given recovery level, thereby increasing the process efficiency and reducing the operating cost of the facility. In addition, the more compact arrangement also eliminates much of the piping used to interconnect the individual equipment items in traditional plant designs, further reducing capital cost and also eliminating the associated flanged piping connections. Since piping flanges are a potential leak source for hydrocarbons (which are volatile organic compounds, VOCs, that contribute to greenhouse gases and may also be precursors to atmospheric ozone formation), eliminating these flanges reduces the potential for atmospheric emissions that can damage the environment. [0012] In accordance with the present invention, it has been found that C 2 recoveries in excess of 95% can be obtained. Similarly, in those instances where recovery of C 2 components is not desired, C 3 recoveries in excess of 95% can be maintained. In addition, the present invention makes possible essentially 100% separation of methane (or C 2 components) and lighter components from the C 2 components (or C 3 components) and heavier components at lower energy requirements compared to the prior art while maintaining the same recovery level. The present invention, although applicable at lower pressures and warmer temperatures, is particularly advantageous when processing feed gases in the range of 400 to 1500 psia [2,758 to 10,342 kPa(a)] or higher under conditions requiring NGL recovery column overhead temperatures of −50° F. [−46° C.] or colder. [0013] For a better understanding of the present invention, reference is made to the following examples and drawings. Referring to the drawings: [0014] FIG. 1 is a flow diagram of a prior art natural gas processing plant in accordance with U.S. Pat. No. 5,568,737; [0015] FIG. 2 is a flow diagram of a natural gas processing plant in accordance with the present invention; and [0016] FIGS. 3 through 9 are flow diagrams illustrating alternative means of application of the present invention to a natural gas stream. [0017] In the following explanation of the above figures, tables are provided summarizing flow rates calculated for representative process conditions. In the tables appearing herein, the values for flow rates (in moles per hour) have been rounded to the nearest whole number for convenience. The total stream rates shown in the tables include all non-hydrocarbon components and hence are generally larger than the sum of the stream flow rates for the hydrocarbon components. Temperatures indicated are approximate values rounded to the nearest degree. It should also be noted that the process design calculations performed for the purpose of comparing the processes depicted in the figures are based on the assumption of no heat leak from (or to) the surroundings to (or from) the process. The quality of commercially available insulating materials makes this a very reasonable assumption and one that is typically made by those skilled in the art. [0018] For convenience, process parameters are reported in both the traditional British units and in the units of the Systeme International d'Unités (SI). The molar flow rates given in the tables may be interpreted as either pound moles per hour or kilogram moles per hour. The energy consumptions reported as horsepower (HP) and/or thousand British Thermal Units per hour (MBTU/Hr) correspond to the stated molar flow rates in pound moles per hour. The energy consumptions reported as kilowatts (kW) correspond to the stated molar flow rates in kilogram moles per hour. DESCRIPTION OF THE PRIOR ART [0019] FIG. 1 is a process flow diagram showing the design of a processing plant to recover C 2 + components from natural gas using prior art according to U.S. Pat. No. 5,568,737. In this simulation of the process, inlet gas enters the plant at 110° F. [43° C.] and 915 psia [6,307 kPa(a)] as stream 31 . If the inlet gas contains a concentration of sulfur compounds which would prevent the product streams from meeting specifications, the sulfur compounds are removed by appropriate pretreatment of the feed gas (not illustrated). In addition, the feed stream is usually dehydrated to prevent hydrate (ice) formation under cryogenic conditions. Solid desiccant has typically been used for this purpose. [0020] The feed stream 31 is divided into two portions, streams 32 and 33 . Stream 32 is cooled to −26° F. [−32° C.] in heat exchanger 10 by heat exchange with cool distillation vapor stream 41 a, while stream 33 is cooled to −32° F. [−35° C.] in heat exchanger 11 by heat exchange with demethanizer reboiler liquids at 41° F. [5° C.] (stream 43 ) and side reboiler liquids at −49° F. [−45° C.] (stream 42 ). Streams 32 a and 33 a recombine to form stream 31 a , which enters separator 12 at −28° F. [−33° C.] and 893 psia [6,155 kPa(a)] where the vapor (stream 34 ) is separated from the condensed liquid (stream 35 ). [0021] The vapor (stream 34 ) from separator 12 is divided into two streams, 36 and 39 . Stream 36 , containing about 27% of the total vapor, is combined with the separator liquid (stream 35 ), and the combined stream 38 passes through heat exchanger 13 in heat exchange relation with cold distillation vapor stream 41 where it is cooled to substantial condensation. The resulting substantially condensed stream 38 a at −139° F. [−95° C.] is then flash expanded through expansion valve 14 to the operating pressure (approximately 396 psia [2,730 kPa(a)]) of fractionation tower 18 . During expansion a portion of the stream is vaporized, resulting in cooling of the total stream. In the process illustrated in FIG. 1 , the expanded stream 38 b leaving expansion valve 14 reaches a temperature of −140° F. [−95° C.] and is supplied to fractionation tower 18 at a first mid-column feed point. [0022] The remaining 73% of the vapor from separator 12 (stream 39 ) enters a work expansion machine 15 in which mechanical energy is extracted from this portion of the high pressure feed. The machine 15 expands the vapor substantially isentropically to the tower operating pressure, with the work expansion cooling the expanded stream 39 a to a temperature of approximately −95° F. [−71° C.]. The typical commercially available expanders are capable of recovering on the order of 80-85% of the work theoretically available in an ideal isentropic expansion. The work recovered is often used to drive a centrifugal compressor (such as item 16 ) that can be used to re-compress the heated distillation vapor stream (stream 41 b ), for example. The partially condensed expanded stream 39 a is thereafter supplied as feed to fractionation tower 18 at a second mid-column feed point. [0023] The recompressed and cooled distillation vapor stream 41 e is divided into two streams. One portion, stream 46 , is the volatile residue gas product. The other portion, recycle stream 45 , flows to heat exchanger 10 where it is cooled to −26° F. [−32° C.] by heat exchange with cool distillation vapor stream 41 a. The cooled recycle stream 45 a then flows to exchanger 13 where it is cooled to −139° F. [−95° C.] and substantially condensed by heat exchange with cold distillation vapor stream 41 . The substantially condensed stream 45 b is then expanded through an appropriate expansion device, such as expansion valve 22 , to the demethanizer operating pressure, resulting in cooling of the total stream to −147° F. [−99° C.]. The expanded stream 45 c is then supplied to fractionation tower 18 as the top column feed. The vapor portion (if any) of stream 45 c combines with the vapors rising from the top fractionation stage of the column to form distillation vapor stream 41 , which is withdrawn from an upper region of the tower. [0024] The demethanizer in tower 18 is a conventional distillation column containing a plurality of vertically spaced trays, one or more packed beds, or some combination of trays and packing. As is often the case in natural gas processing plants, the fractionation tower may consist of two sections. The upper section 18 a is a separator wherein the partially vaporized top feed is divided into its respective vapor and liquid portions, and wherein the vapor rising from the lower distillation or demethanizing section 18 b is combined with the vapor portion of the top feed to form the cold demethanizer overhead vapor (stream 41 ) which exits the top of the tower at −144° F. [−98° C.]. The lower, demethanizing section 18 b contains the trays and/or packing and provides the necessary contact between the liquids falling downward and the vapors rising upward. The demethanizing section 18 b also includes reboilers (such as the reboiler and the side reboiler described previously) which heat and vaporize a portion of the liquids flowing down the column to provide the stripping vapors which flow up the column to strip the liquid product, stream 44 , of methane and lighter components. [0025] The liquid product stream 44 exits the bottom of the tower at 64 ° F. [18° C.], based on a typical specification of a methane to ethane ratio of 0.010:1 on a mass basis in the bottom product. The demethanizer overhead vapor stream 41 passes countercurrently to the incoming feed gas and recycle stream in heat exchanger 13 where it is heated to −40° F. [−40° C.] (stream 41 a ) and in heat exchanger 10 where it is heated to 104° F. [40° C.] (stream 41 b ). The distillation vapor stream is then re-compressed in two stages. The first stage is compressor 16 driven by expansion machine 15 . The second stage is compressor 20 driven by a supplemental power source which compresses the residue gas (stream 41 d ) to sales line pressure. After cooling to 110° F. [43° C.] in discharge cooler 21 , stream 41 e is split into the residue gas product (stream 46 ) and the recycle stream 45 as described earlier. Residue gas stream 46 flows to the sales gas pipeline at 915 psia [6,307 kPa(a)], sufficient to meet line requirements (usually on the order of the inlet pressure). [0026] A summary of stream flow rates and energy consumption for the process illustrated in FIG. 1 is set forth in the following table: [0000] TABLE I (FIG. 1) Stream Flow Summary - Lb. Moles/Hr [kg moles/Hr] Stream Methane Ethane Propane Butanes+ Total 31 12,398 546 233 229 13,726 32 8,431 371 159 156 9,334 33 3,967 175 74 73 4,392 34 12,195 501 179 77 13,261 35 203 45 54 152 465 36 3,317 136 49 21 3,607 38 3,520 181 103 173 4,072 39 8,878 365 130 56 9,654 41 13,765 30 0 0 13,992 45 1,377 3 0 0 1,400 46 12,388 27 0 0 12,592 44 10 519 233 229 1,134 Recoveries* [0027] [0000] Ethane 94.99% Propane 99.99% Butanes+ 100.00% Power [0028] [0000] Residue Gas Compression 6,149 HP [10,109 kW] * (Based on un-rounded flow rates) DESCRIPTION OF THE INVENTION [0029] FIG. 2 illustrates a flow diagram of a process in accordance with the present invention. The feed gas composition and conditions considered in the process presented in FIG. 2 are the same as those in FIG. 1 . Accordingly, the FIG. 2 process can be compared with that of the FIG. 1 process to illustrate the advantages of the present invention. [0030] In the simulation of the FIG. 2 process, inlet gas enters the plant as stream 31 and is divided into two portions, streams 32 and 33 . The first portion, stream 32 , enters a heat exchange means in the upper region of feed cooling section 118 a inside processing assembly 118 . This heat exchange means may be comprised of a fin and tube type heat exchanger, a plate type heat exchanger, a brazed aluminum type heat exchanger, or other type of heat transfer device, including multi-pass and/or multi-service heat exchangers. The heat exchange means is configured to provide heat exchange between stream 32 flowing through one pass of the heat exchange means and a distillation vapor stream arising from separator section 118 b inside processing assembly 118 that has been heated in a heat exchange means in the lower region of feed cooling section 118 a. Stream 32 is cooled while further heating the distillation vapor stream, with stream 32 a leaving the heat exchange means at −25° F. [−32° C.]. [0031] The second portion, stream 33 , enters a heat and mass transfer means in demethanizing section 118 e inside processing assembly 118 . This heat and mass transfer means may also be comprised of a fin and tube type heat exchanger, a plate type heat exchanger, a brazed aluminum type heat exchanger, or other type of heat transfer device, including multi-pass and/or multi-service heat exchangers. The heat and mass transfer means is configured to provide heat exchange between stream 33 flowing through one pass of the heat and mass transfer means and a distillation liquid stream flowing downward from absorbing section 118 d inside processing assembly 118 , so that stream 33 is cooled while heating the distillation liquid stream, cooling stream 33 a to −47° F. [−44° C.] before it leaves the heat and mass transfer means. As the distillation liquid stream is heated, a portion of it is vaporized to form stripping vapors that rise upward as the remaining liquid continues flowing downward through the heat and mass transfer means. The heat and mass transfer means provides continuous contact between the stripping vapors and the distillation liquid stream so that it also functions to provide mass transfer between the vapor and liquid phases, stripping the liquid product stream 44 of methane and lighter components. [0032] Streams 32 a and 33 a recombine to form stream 31 a , which enters separator section 118 f inside processing assembly 118 at −32° F. [−36° C.] and 900 psia [6,203 kPa(a)], whereupon the vapor (stream 34 ) is separated from the condensed liquid (stream 35 ). Separator section 118 f has an internal head or other means to divide it from demethanizing section 118 e, so that the two sections inside processing assembly 118 can operate at different pressures. [0033] The vapor (stream 34 ) from separator section 118 f is divided into two streams, 36 and 39 . Stream 36 , containing about 27% of the total vapor, is combined with the separated liquid (stream 35 , via stream 37 ), and the combined stream 38 enters a heat exchange means in the lower region of feed cooling section 118 a inside processing assembly 118 . This heat exchange means may likewise be comprised of a fin and tube type heat exchanger, a plate type heat exchanger, a brazed aluminum type heat exchanger, or other type of heat transfer device, including multi-pass and/or multi-service heat exchangers. The heat exchange means is configured to provide heat exchange between stream 38 flowing through one pass of the heat exchange means and the distillation vapor stream arising from separator section 118 b, so that stream 38 is cooled to substantial condensation while heating the distillation vapor stream. [0034] The resulting substantially condensed stream 38 a at −138° F. [−95° C.] is then flash expanded through expansion valve 14 to the operating pressure (approximately 400 psia [2,758 kPa(a)]) of rectifying section 118 c (an absorbing means) and absorbing section 118 d (another absorbing means) inside processing assembly 118 . During expansion a portion of the stream may be vaporized, resulting in cooling of the total stream. In the process illustrated in FIG. 2 , the expanded stream 38 b leaving expansion valve 14 reaches a temperature of −139° F. [−95° C.] and is supplied to processing assembly 118 between rectifying section 118 c and absorbing section 118 d. The liquids in stream 38 b combine with the liquids falling from rectifying section 118 c and are directed to absorbing section 118 d, while any vapors combine with the vapors rising from absorbing section 118 d and are directed to rectifying section 118 c. [0035] The remaining 73% of the vapor from separator section 118 f (stream 39 ) enters a work expansion machine 15 in which mechanical energy is extracted from this portion of the high pressure feed. The machine 15 expands the vapor substantially isentropically to the operating pressure of absorbing section 118 d, with the work expansion cooling the expanded stream 39 a to a temperature of approximately −99° F. [−73° C.]. The partially condensed expanded stream 39 a is thereafter supplied as feed to the lower region of absorbing section 118 d inside processing assembly 118 . [0036] The recompressed and cooled distillation vapor stream 41 c is divided into two streams. One portion, stream 46 , is the volatile residue gas product. The other portion, recycle stream 45 , enters a heat exchange means in the feed cooling section 118 a inside processing assembly 118 . This heat exchange means may also be comprised of a fin and tube type heat exchanger, a plate type heat exchanger, a brazed aluminum type heat exchanger, or other type of heat transfer device, including multi-pass and/or multi-service heat exchangers. The heat exchange means is configured to provide heat exchange between stream 45 flowing through one pass of the heat exchange means and the distillation vapor stream arising from separator section 118 b, so that stream 45 is cooled to substantial condensation while heating the distillation vapor stream. [0037] The substantially condensed recycle stream 45 a leaves the heat exchange means in feed cooling section 118 a at −138° F. [−95° C.] and is flash expanded through expansion valve 22 to the operating pressure of rectifying section 118 c inside processing assembly 118 . During expansion a portion of the stream is vaporized, resulting in cooling of the total stream. In the process illustrated in FIG. 2 , the expanded stream 45 b leaving expansion valve 22 reaches a temperature of −146° F. [−99° C.] and is supplied to separator section 118 b inside processing assembly 118 . The liquids separated therein are directed to rectifying section 118 c, while the remaining vapors combine with the vapors rising from rectifying section 118 c to form the distillation vapor stream that is heated in cooling section 118 a. [0038] Rectifying section 118 c and absorbing section 118 d each contain an absorbing means consisting of a plurality of vertically spaced trays, one or more packed beds, or some combination of trays and packing. The trays and/or packing in rectifying section 118 c and absorbing section 118 d provide the necessary contact between the vapors rising upward and cold liquid falling downward. The liquid portion of the expanded stream 39 a commingles with liquids falling downward from absorbing section 118 d and the combined liquid continues downward into demethanizing section 118 e. The stripping vapors arising from demethanizing section 118 e combine with the vapor portion of the expanded stream 39 a and rise upward through absorbing section 118 d, to be contacted with the cold liquid falling downward to condense and absorb most of the C 2 components, C 3 components, and heavier components from these vapors. The vapors arising from absorbing section 118 d combine with any vapor portion of the expanded stream 38 b and rise upward through rectifying section 118 c, to be contacted with the cold liquid portion of expanded stream 45 b falling downward to condense and absorb most of the C 2 components, C 3 components, and heavier components remaining in these vapors. The liquid portion of the expanded stream 38 b commingles with liquids falling downward from rectifying section 118 c and the combined liquid continues downward into absorbing section 118 d. [0039] The distillation liquid flowing downward from the heat and mass transfer means in demethanizing section 118 e inside processing assembly 118 has been stripped of methane and lighter components. The resulting liquid product (stream 44 ) exits the lower region of demethanizing section 118 e and leaves processing assembly 118 at 65° F. [18° C.]. The distillation vapor stream arising from separator section 118 b is warmed in feed cooling section 118 a as it provides cooling to streams 32 , 38 , and 45 as described previously, and the resulting distillation vapor stream 41 leaves processing assembly 118 at 105° F. [40° C.]. The distillation vapor stream is then re-compressed in two stages, compressor 16 driven by expansion machine 15 and compressor 20 driven by a supplemental power source. After stream 41 b is cooled to 110° F. [43° C.] in discharge cooler 21 to form stream 41 c, recycle stream 45 is withdrawn as described earlier, forming residue gas stream 46 which thereafter flows to the sales gas pipeline at 915 psia [6,307 kPa(a)]. [0040] A summary of stream flow rates and energy consumption for the process illustrated in FIG. 2 is set forth in the following table: [0000] TABLE II (FIG. 2) Stream Flow Summary - Lb. Moles/Hr [kg moles/Hr] Stream Methane Ethane Propane Butanes+ Total 31 12,398 546 233 229 13,726 32 8,679 382 163 160 9,608 33 3,719 164 70 69 4,118 34 12,164 495 174 72 13,213 35 234 51 59 157 513 36 3,248 132 46 19 3,528 37 234 51 59 157 513 38 3,482 183 105 176 4,041 39 8,916 363 128 53 9,685 40 0 0 0 0 0 41 13,863 30 0 0 14,095 45 1,475 3 0 0 1,500 46 12,388 27 0 0 12,595 44 10 519 233 229 1,131 Recoveries* [0041] [0000] Ethane 95.03% Propane 99.99% Butanes+ 100.00% Power [0042] [0000] Residue Gas Compression 5,787 HP [9,514 kW] * (Based on un-rounded flow rates) [0043] A comparison of Tables I and II shows that the present invention maintains essentially the same recoveries as the prior art. However, further comparison of Tables I and II shows that the product yields were achieved using significantly less power than the prior art. In terms of the recovery efficiency (defined by the quantity of ethane recovered per unit of power), the present invention represents more than a 6 % improvement over the prior art of the FIG. 1 process. [0044] The improvement in recovery efficiency provided by the present invention over that of the prior art of the FIG. 1 process is primarily due to two factors. First, the compact arrangement of the heat exchange means in feed cooling section 118 a and the heat and mass transfer means in demethanizing section 118 e in processing assembly 118 eliminates the pressure drop imposed by the interconnecting piping found in conventional processing plants. The result is that the portion of the feed gas flowing to expansion machine 15 is at higher pressure for the present invention compared to the prior art, allowing expansion machine 15 in the present invention to produce as much power with a higher outlet pressure as expansion machine 15 in the prior art can produce at a lower outlet pressure. Thus, rectifying section 118 c and absorbing section 118 d in processing assembly 118 of the present invention can operate at higher pressure than fractionation column 18 of the prior art while maintaining the same recovery level. This higher operating pressure, plus the reduction in pressure drop for the distillation vapor stream due to eliminating the interconnecting piping, results in a significantly higher pressure for the distillation vapor stream entering compressor 20 , thereby reducing the power required by the present invention to restore the residue gas to pipeline pressure. [0045] Second, using the heat and mass transfer means in demethanizing section 118 e to simultaneously heat the distillation liquid leaving absorbing section 118 d while allowing the resulting vapors to contact the liquid and strip its volatile components is more efficient than using a conventional distillation column with external reboilers. The volatile components are stripped out of the liquid continuously, reducing the concentration of the volatile components in the stripping vapors more quickly and thereby improving the stripping efficiency for the present invention. [0046] The present invention offers two other advantages over the prior art in addition to the increase in processing efficiency. First, the compact arrangement of processing assembly 118 of the present invention replaces five separate equipment items in the prior art (heat exchangers 10 , 11 , and 13 ; separator 12 ; and fractionation tower 18 in FIG. 1 ) with a single equipment item (processing assembly 118 in FIG. 2 ). This reduces the plot space requirements and eliminates the interconnecting piping, reducing the capital cost of a process plant utilizing the present invention over that of the prior art. Second, elimination of the interconnecting piping means that a processing plant utilizing the present invention has far fewer flanged connections compared to the prior art, reducing the number of potential leak sources in the plant. [0047] Hydrocarbons are volatile organic compounds (VOCs), some of which are classified as greenhouse gases and some of which may be precursors to atmospheric ozone formation, which means the present invention reduces the potential for atmospheric releases that can damage the environment. Other Embodiments [0048] Some circumstances may favor supplying liquid stream 35 directly to the lower region of absorbing section 118 d via stream 40 as shown in FIGS. 2 , 4 , 6 , and 8 . In such cases, an appropriate expansion device (such as expansion valve 17 ) is used to expand the liquid to the operating pressure of absorbing section 118 d and the resulting expanded liquid stream 40 a is supplied as feed to the lower region of absorbing section 118 d (as shown by the dashed lines). Some circumstances may favor combining a portion of liquid stream 35 (stream 37 ) with the vapor in stream 36 ( FIGS. 2 and 6 ) or with cooled second portion 33 a ( FIGS. 4 and 8 ) to form combined stream 38 and routing the remaining portion of liquid stream 35 to the lower region of absorbing section 118 d via streams 40 / 40 a. Some circumstances may favor combining the expanded liquid stream 40 a with expanded stream 39 a ( FIGS. 2 and 6 ) or expanded stream 34 a ( FIGS. 4 and 8 ) and thereafter supplying the combined stream to the lower region of absorbing section 118 d as a single feed. [0049] If the feed gas is richer, the quantity of liquid separated in stream 35 may be great enough to favor placing an additional mass transfer zone in demethanizing section 118 e between expanded stream 39 a and expanded liquid stream 40 a as shown in FIGS. 3 and 7 , or between expanded stream 34 a and expanded liquid stream 40 a as shown in FIGS. 5 and 9 . In such cases, the heat and mass transfer means in demethanizing section 118 e may be configured in upper and lower parts so that expanded liquid stream 40 a can be introduced between the two parts. As shown by the dashed lines, some circumstances may favor combining a portion of liquid stream 35 (stream 37 ) with the vapor in stream 36 ( FIGS. 3 and 7 ) or with cooled second portion 33 a ( FIGS. 5 and 9 ) to form combined stream 38 , while the remaining portion of liquid stream 35 (stream 40 ) is expanded to lower pressure and supplied between the upper and lower parts of the heat and mass transfer means in demethanizing section 118 e as stream 40 a. [0050] Some circumstances may favor not combining the cooled first and second portions (streams 32 a and 33 a ) as shown in FIGS. 4 , 5 , 8 , and 9 . In such cases, only the cooled first portion 32 a is directed to separator section 118 f inside processing assembly 118 ( FIGS. 4 and 5 ) or separator 12 ( FIGS. 8 and 9 ) where the vapor (stream 34 ) is separated from the condensed liquid (stream 35 ). Vapor stream 34 enters work expansion machine 15 and is expanded substantially isentropically to the operating pressure of absorbing section 118 d , whereupon expanded stream 34 a is supplied as feed to the lower region of absorbing section 118 d inside processing assembly 118 . The cooled second portion 33 a is combined with the separated liquid (stream 35 , via stream 37 ), and the combined stream 38 is directed to the heat exchange means in the lower region of feed cooling section 118 a inside processing assembly 118 and cooled to substantial condensation. The substantially condensed stream 38 a is flash expanded through expansion valve 14 to the operating pressure of rectifying section 118 c and absorbing section 118 d, whereupon expanded stream 38 b is supplied to processing assembly 118 between rectifying section 118 c and absorbing section 118 d. Some circumstances may favor combining only a portion (stream 37 ) of liquid stream 35 with the cooled second portion 33 a , with the remaining portion (stream 40 ) supplied to the lower region of absorbing section 118 d via expansion valve 17 . Other circumstances may favor sending all of liquid stream 35 to the lower region of absorbing section 118 d via expansion valve 17 . [0051] In some circumstances, it may be advantageous to use an external separator vessel to separate cooled feed stream 31 a or cooled first portion 32 a, rather than including separator section 118 f in processing assembly 118 . As shown in FIGS. 6 and 7 , separator 12 can be used to separate cooled feed stream 31 a into vapor stream 34 and liquid stream 35 . Likewise, as shown in FIGS. 8 and 9 , separator 12 can be used to separate cooled first portion 32 a into vapor stream 34 and liquid stream 35 . [0052] Depending on the quantity of heavier hydrocarbons in the feed gas and the feed gas pressure, the cooled feed stream 31 a entering separator section 118 f in FIGS. 2 and 3 or separator 12 in FIGS. 6 and 7 (or the cooled first portion 32 a entering separator section 118 f in FIGS. 4 and 5 or separator 12 in FIGS. 8 and 9 ) may not contain any liquid (because it is above its dewpoint, or because it is above its cricondenbar). In such cases, there is no liquid in streams 35 and 37 (as shown by the dashed lines), so only the vapor from separator section 118 f in stream 36 ( FIGS. 2 and 3 ), the vapor from separator 12 in stream 36 ( FIGS. 6 and 7 ), or the cooled second portion 33 a ( FIGS. 4 , 5 , 8 , and 9 ) flows to stream 38 to become the expanded substantially condensed stream 38 b supplied to processing assembly 118 between rectifying section 118 c and absorbing section 118 d. In such circumstances, separator section 118 f in processing assembly 118 ( FIGS. 2 through 5 ) or separator 12 ( FIGS. 6 through 9 ) may not be required. [0053] Feed gas conditions, plant size, available equipment, or other factors may indicate that elimination of work expansion machine 15 , or replacement with an alternate expansion device (such as an expansion valve), is feasible. Although individual stream expansion is depicted in particular expansion devices, alternative expansion means may be employed where appropriate. For example, conditions may warrant work expansion of the substantially condensed portion of the feed stream (stream 38 a ) or the substantially condensed recycle stream (stream 45 a ). [0054] In accordance with the present invention, the use of external refrigeration to supplement the cooling available to the inlet gas from the distillation vapor and liquid streams may be employed, particularly in the case of a rich inlet gas. In such cases, a heat and mass transfer means may be included in separator section 118 f (or a collecting means in such cases when the cooled feed stream 31 a or the cooled first portion 32 a contains no liquid) as shown by the dashed lines in FIGS. 2 through 5 , or a heat and mass transfer means may be included in separator 12 as shown by the dashed lines in FIGS. 6 though 9 . This heat and mass transfer means may be comprised of a fin and tube type heat exchanger, a plate type heat exchanger, a brazed aluminum type heat exchanger, or other type of heat transfer device, including multi-pass and/or multi-service heat exchangers. The heat and mass transfer means is configured to provide heat exchange between a refrigerant stream (e.g., propane) flowing through one pass of the heat and mass transfer means and the vapor portion of stream 31 a ( FIGS. 2 , 3 , 6 , and 7 ) or stream 32 a ( FIGS. 4 , 5 , 8 , and 9 ) flowing upward, so that the refrigerant further cools the vapor and condenses additional liquid, which falls downward to become part of the liquid removed in stream 35 . Alternatively, conventional gas chiller(s) could be used to cool stream 32 a, stream 33 a, and/or stream 31 a with refrigerant before stream 31 a enters separator section 118 f ( FIGS. 2 and 3 ) or separator 12 ( FIGS. 6 and 7 ) or stream 32 a enters separator section 118 f ( FIGS. 4 and 5 ) or separator 12 ( FIGS. 8 and 9 ). [0055] Depending on the temperature and richness of the feed gas and the amount of C 2 components to be recovered in liquid product stream 44 , there may not be sufficient heating available from stream 33 to cause the liquid leaving demethanizing section 118 e to meet the product specifications. In such cases, the heat and mass transfer means in demethanizing section 118 e may include provisions for providing supplemental heating with heating medium as shown by the dashed lines in FIGS. 2 through 9 . Alternatively, another heat and mass transfer means can be included in the lower region of demethanizing section 118 e for providing supplemental heating, or stream 33 can be heated with heating medium before it is supplied to the heat and mass transfer means in demethanizing section 118 e. [0056] Depending on the type of heat transfer devices selected for the heat exchange means in the upper and lower regions of feed cooling section 118 a, it may be possible to combine these heat exchange means in a single multi-pass and/or multi-service heat transfer device. In such cases, the multi-pass and/or multi-service heat transfer device will include appropriate means for distributing, segregating, and collecting stream 32 , stream 38 , stream 45 , and the distillation vapor stream in order to accomplish the desired cooling and heating. [0057] Some circumstances may favor providing additional mass transfer in the upper region of demethanizing section 118 e. In such cases, a mass transfer means can be located below where expanded stream 39 a ( FIGS. 2 , 3 , 6 , and 7 ) or expanded stream 34 a ( FIGS. 4 , 5 , 8 , and 9 ) enters the lower region of absorbing section 118 d and above where cooled second portion 33 a leaves the heat and mass transfer means in demethanizing section 118 e. [0058] A less preferred option for the FIGS. 2 , 3 , 6 , and 7 embodiments of the present invention is providing a separator vessel for cooled first portion 31 a , a separator vessel for cooled second portion 32 a, combining the vapor streams separated therein to form vapor stream 34 , and combining the liquid streams separated therein to form liquid stream 35 . Another less preferred option for the present invention is cooling stream 37 in a separate heat exchange means inside feed cooling section 118 a (rather than combining stream 37 with stream 36 or stream 33 a to form combined stream 38 ), expanding the cooled stream in a separate expansion device, and supplying the expanded stream to an intermediate region in absorbing section 118 d. [0059] It will be recognized that the relative amount of feed found in each branch of the split vapor feed will depend on several factors, including gas pressure, feed gas composition, the amount of heat which can economically be extracted from the feed, and the quantity of horsepower available. More feed above absorbing section 118 d may increase recovery while decreasing power recovered from the expander and thereby increasing the recompression horsepower requirements. Increasing feed below absorbing section 118 d reduces the horsepower consumption but may also reduce product recovery. [0060] The present invention provides improved recovery of C 2 components, C 3 components, and heavier hydrocarbon components or of C 3 components and heavier hydrocarbon components per amount of utility consumption required to operate the process. An improvement in utility consumption required for operating the process may appear in the form of reduced power requirements for compression or re-compression, reduced power requirements for external refrigeration, reduced energy requirements for supplemental heating, or a combination thereof. [0061] While there have been described what are believed to be preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto, e.g. to adapt the invention to various conditions, types of feed, or other requirements without departing from the spirit of the present invention as defined by the following claims.

A process and an apparatus are disclosed for the recovery of ethane, ethylene, propane, propylene, and heavier hydrocarbon components from a hydrocarbon gas stream in a compact processing assembly. The gas stream is cooled and divided into first and second streams. The first stream is further cooled to condense substantially all of it and is thereafter expanded to lower pressure and supplied as a feed between first and second absorbing means inside the processing assembly. The second stream is expanded to lower pressure and supplied as the bottom feed to the second absorbing means. A distillation vapor stream is collected from the upper region of the first absorbing means and directed into one or more heat exchange means inside the processing assembly to heat it while cooling the gas stream and the first stream. The heated distillation vapor stream is compressed to higher pressure and divided into a volatile residue gas fraction and a compressed recycle stream. The compressed recycle stream is cooled to condense substantially all of it by the distillation vapor stream in the one or more heat exchange means inside the processing assembly, and is thereafter expanded to lower pressure and supplied as top feed to the first absorbing means. A distillation liquid stream is collected from the lower region of the second absorbing means and directed into a heat and mass transfer means inside the processing assembly to heat it and strip out its volatile components while cooling the gas stream. The quantities and temperatures of the feeds to the first and second absorbing means are effective to maintain the temperature of the upper region of the first absorbing means at a temperature whereby the major portions of the desired components are recovered in the stripped distillation liquid stream.

RELATED APPLICATIONS [0001] This nonprovisional patent application claims priority to U.S. provisional patent application Ser. No. 61/835,684, filed Jun. 17, 2013, titled “Automatic Threshold Detection for Tachometer Signals,” the entire contents of which are incorporated herein by reference. FIELD [0002] This invention relates to analysis of machine vibration data. More particularly, this invention relates to a method for automatically determining a proper threshold for a tachometer signal in order to produce the desired tachometer pulses necessary for analysis of machine vibration data. BACKGROUND [0003] One of the most important characteristics of machine operation used in the analysis of vibration data is the rotational speed of the machine. Machine speed is often acquired from tachometer measurements. Accurate tachometer pulses are essential for applications such as order tracking, synchronous time averaging, single channel phase, Bode plots, and general turning speed calculations. Ideally, tachometer pulses are generated when illumination from a tachometer sensor passes over a section of reflective tape placed on a rotating portion of the machine, such as a rotating shaft. However, the shafts of most machines in industry do not have reflective tape. If they have reflective tape, often times the tape is covered with grime or has rubbed off or is otherwise damaged to some extent. Because a machine typically cannot be stopped in order to place reflective tape on the shaft, an analyst will collect tachometer data in hopes of getting a trigger from a keyway, a scratch on the shaft, or remnants of old reflective tape. The resulting tachometer waveform is typically noisy and small in amplitude and the tachometer pulses are not very distinctive. [0004] An ideal tachometer waveform consists of a series of distinct pulses, wherein each pulse indicates a single revolution of the shaft. To generate a tachometer pulse sufficient for the applications mentioned above, a threshold is set such that a rising (or falling) edge of the tachometer signal triggers a pulse when it passes the threshold. This threshold is manually entered by an analyst. In an ideal situation, where reflective tape is present resulting in a strong tachometer signal, the chosen threshold value will generally be acceptable for all measurements. However, when reflective tape is not present, the level of the tachometer signal varies from one machine to the next and the necessary threshold will be different for each measurement. [0005] What is needed, therefore, is an automatic method for calculating a proper threshold for a given tachometer signal in order to produce the desired tachometer pulses needed for machine vibration analysis. SUMMARY [0006] The various embodiments of the invention described herein extract an event from data. The data of interest is generally characterized by a rapid change in a signal amplitude. By applying a derivative to the signal, these rapid changes in amplitude become more evident and are much easier to see and quantify. When evaluating tachometer signals associated with a machine being monitored, the rapid change in signal amplitude occurs at a rate substantially equivalent to the running speed of the machine. Such tachometer signals may be generated by various sources, including but not limited to laser, optical, eddy current, magnetic, and LED sources. [0007] Embodiments of the invention can also be applied to vibration signals having repetitive and impulsive features. One example of an impulsive signal is a signal associated with a bearing defect. By taking the derivative of an acceleration waveform (sometimes referred to as a “jerk”), a threshold value can be calculated using an embodiment of the invention that extracts a repetitive signal associated with the impulsive characteristic generated from a defective bearing. Embodiments of the invention may be applied to any vibration waveform to extract information associated with impulse-driven information. [0008] A preferred method embodiment begins by passing a tachometer signal through a low-pass filter to exclude high-frequency noise. Preferably, the low-pass corner frequency of the filter is 250 Hz, but depending on the signal the desired corner frequency may vary between 100 Hz and 1000 Hz. Next, a running derivative of the filtered tachometer waveform is taken. The resulting signal is referred to herein as the derivative waveform (“Deriv_WF”). A new waveform is then created that includes only positive values from the derivative waveform that correspond to positive values in the associated low-pass filtered tachometer waveform. This new waveform is referred to herein as Deriv>0_WF. In general, a tachometer signal has the greatest derivative value (slope) when a tachometer pulse is present. Based on this observation, preferred embodiments of the method derive a threshold value using both the low-pass filtered tachometer waveform and Deriv>0_WF along with statistics from both waveforms. In alternative embodiments, a Deriv<0_WF waveform is derived using only negative values in the associated low-pass filtered tachometer waveform. A negative threshold value may be calculated for negative going pulses such as generated by proximity probe tachometers. [0009] In preferred embodiments, determination of the tachometer threshold value is based on finding a specified number of peaks in the Deriv>0_WF waveform and locating their associated peaks in the low-pass filtered tachometer waveform. Using a combination of statistics derived from both waveforms, one of three options will be selected: (1) a threshold is determined for the low-pass filtered waveform, which in turn is used to produce tachometer pulses; (2) although the low-pass filtered waveform does not provide a sufficient signal to produce a tachometer pulse, the associated Deriv>0_WF waveform does provide the information needed and therefore a threshold is calculated and applied to the Deriv>0_WF waveform that is used to generate tachometer pulses; [0012] (3) neither the low-pass filtered waveform nor Deriv>0_WF contains the necessary characteristics to produce a reliable tachometer pulse and the analyst is warned that the acquired signal is insufficient to generate tachometer pulses. [0013] Preferred embodiments of the method include: (1) three different methods to determine peaks in the Deriv>0_WF; (2) the ability to sort out peak values that are not consistent with peak values associated with the running speed; (3) determination of the threshold value based on various statistical criteria. [0017] Peaks representative of tachometer pulses in the raw tachometer waveform are determined from the peaks found in the Deriv>0_WF waveform. The Deriv>0_WF waveform consists of subsets or groups of positive peak values. (For example, in FIG. 4 , such a group (or subset) contains all the peaks found between “A” and “E.” Another group contains the single peak between “F” and “G.”) In some embodiments of the method, the peaks in Deriv>0_WF are found as the first peak of a group of positive peak values. In alternative embodiments, the selected peaks in Deriv>0_WF correspond to either the largest derivative value or the last peak from each group of peak values. To ensure that the selected set of Deriv>0_WF peaks are associated only with the speed of the machine, outlying peaks are culled out using a sorting routine described hereinafter. This routine preferably includes four methods to determine the selected peaks based on calculations of the mean and standard deviation of the set of peaks. [0018] Alternative embodiments of the method may employ a different statistical process, such as a mode, to find a frequently recurring family of peaks within the derivative waveform. For example, a statistical histogram, a cumulative distribution, or another probability density technique may be implemented to detect and identify a range of interest based on a mode or a most frequently recurring subset of data values within a population of data values from the derivative waveform. BRIEF DESCRIPTION OF THE DRAWINGS [0019] Further advantages of the invention are apparent by reference to the detailed description in conjunction with the figures, wherein elements are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein: [0020] FIG. 1 depicts a functional block diagram of a system for deriving information from a tachometer signal according to an embodiment of the invention; [0021] FIGS. 2 and 3 depict flowcharts of steps of a method for determining a threshold for a tachometer signal according to a preferred embodiment of the invention; and [0022] FIG. 4 depicts a portion of an example filtered tachometer waveform and a corresponding running derivative waveform. DETAILED DESCRIPTION [0023] FIG. 1 depicts a system 100 for deriving information from a tachometer signal. In the embodiment of FIG. 1 , a tachometer 104 is attached to a machine 102 to monitor the rotational speed of a component of the machine 102 , such as a rotating shaft. The tachometer 104 generates a tachometer signal that contains information about the rotational speed of the machine 102 . The tachometer signal is provided to a data collector 106 comprising an analog-to-digital converter (ADC) 108 for sampling the tachometer signal, a low-pass filter 110 , and buffer memory 112 . The data collector 106 may be a digital data recorder manufactured by TEAC or a vibration data collector. In a preferred embodiment, the ADC 108 samples the tachometer signal at 48,000 samples/second. The low-pass filter 110 is preferably an FIR filter with 49 taps, preferably with a corner frequency set between 250 and 1000 Hz. In a preferred embodiment, the low-pass corner frequency is set at 250 Hz for rotational speeds of 900 RPM and higher. [0024] In the embodiment of FIG. 1 , the tachometer signal data is transferred from the data collector 106 to a threshold processor 114 that performs the calculations and other information processing tasks described herein. In an alternative embodiment, the calculations and processing are performed by a processor in the data collector 106 . [0025] As depicted in FIG. 2 , a preferred method 10 for determining a threshold for a tachometer signal begins with the collection of the raw tachometer data (step 12 ). The tachometer signal data is passed through the low-pass filter 110 (step 14 ), which generates a filtered signal at its output referred to herein as “Filtered_WF.” [0026] Once Filtered_WF is stable (after about the 50 th sample), the root-mean-square (RMS) value of Filtered_WF is calculated (step 16 ), and the waveform is centered about the RMS value and then centered about zero with the RMS offset (DC offset) (step 18 ). The Crest Factor (CF) for Filtered_WF is then calculated according to: [0000] C   F = Largest   peak   of   Filtered_WF RMS   of   Filtered_WF . ( step   20 ) [0000] This value is referred to herein as Filtered_WF_CF_RMS. [0027] A running derivative of Filtered_WF is taken which is referred to as the Deriv_WF signal (step 22 ), wherein the zero value derivative point at the beginning is dropped. The Crest Factor (CF) for the Deriv_WF signal is calculated according to: [0000] C   F = Largest   peak   of   Deriv_WF RMS   of   Deriv_WF . ( step   24 ) [0000] This value is referred to as Deriv_CF_RMS. [0028] Using the Deriv_WF signal, a new waveform is created from the positive values in Filtered_WF that have only the positive derivative values (slopes). The new waveform retains all values that are greater than zero while setting all negative values (i.e. slope≦0) to zero (step 26 ). The resulting signal, referred to herein as Deriv>0_WF, looks like a “rectified” version of Deriv_WF, although this waveform is not actually rectified. Specifically, values greater than zero in Filtered_WF are determined, the slope of the resulting signal is calculated, and any slopes that are less than or equal to zero are set to zero. The mean value (μ) of the resulting signal is found and referred to as Deriv>0_Mean, and the standard deviation (σ) is found and referred to as Deriv>0_SD (step 28 ). In the preferred embodiment, values of zero are not used to calculate Deriv>0_Mean and Deriv>0_SD. In some embodiments, Deriv>0_WF is created in an opposite manner using only the negative slope of Deriv_WF, and the absolute value is taken of the resulting signal for further analysis. [0029] The upper portion of FIG. 4 depicts an example of Deriv>0_WF showing a set of peaks starting after 0.0075 seconds (point “A”) and ending just after 0.01 seconds (point “E”). The lower portion of FIG. 4 is the corresponding Filtered_WF that was used to produce Deriv>0_WF in the upper portion. The vertical lines show the derivative (slope) values associated with points in Filtered_WF. [0030] In a preferred embodiment, all peaks in Deriv>0_WF are found by one of three methods (step 30 ). Each method evaluates every group of points defined as a set of points (positive derivatives) bounded by zero: (1) The first peak in each set is evaluated. In this method, the peak is the first peak of the set where the peak is the most positive value before becoming less positive. For example, see point “B” in FIG. 4 . (2) Choose the “steepest” slope or largest derivative. This will be the tallest peak in each set. The tallest peak is associated with the steepest slope in the set. For example, see point “C” in FIG. 4 . (3) Choose the last peak in the set. This point is associated with the steepest slope of the line just before the peak occurs in Filtered_WF. For example, see point “D” in FIG. 4 . [0034] The N number of largest peaks are then found in Deriv>0_WF (step 32 ). The value of N can be user-selected or calculated as described in a process performed in a preferred embodiment to calculate the number of peaks for analysis. Typically, N is 20 for one second of data at speeds greater than 1800 RPM. The largest of these N peaks is found and the Crest Factor (CF) for the Deriv>0_WF data is determined according to: [0000] C   F = Largest   of   N   peaks   of   Deriv > 0  _WF RMS   of   Deriv > 0  _WF . ( step   34 ) [0000] This value is referred to as Deriv>0_CF_RMS. When calculating the RMS value of the Deriv>0_WF, values of zero are included. [0035] The N peaks found in step 32 are sorted by amplitude from largest to smallest (step 36 ), and any of the N peaks greater than the boundary of μ+σ are discarded as outliers (step 38 ). A statistical method used in a preferred embodiment to discard the outlier data is described in hereinafter (method 2). A Crest Factor for the remaining values is calculated according to: [0000] C   F = Largest   of   N   peaks   of   Deriv > 0  _WF   excluding_outliers RMS   of   Deriv > 0  _WF  _excluding  _outliers . ( step   40 ) [0000] This value is referred to as Adj_Deriv>0_CF_RMS. Preferably, the RMS calculation used for the Adj_Deriv>0_CF_RMS value does not incorporate the discarded peak values. [0036] Next locations in Deriv>0_WF are determined where the signal crosses zero to the right of the peaks ( FIG. 4 , points “E” and “G”) (step 42 ). These locations coincide with a peak in the Filtered_WF signal. The “base” value of Deriv>0_WF is then determined for each of the N peaks found in step 32 (step 44 ). This base value is preferably associated with the zero crossing of the Filtered_WF signal as indicated by point “A” in FIG. 4 or at a value where the derivative (slope) changes from negative to positive, such as point “F” in FIG. 4 which corresponds to a valley in the Filtered_WF data where the derivative changes from negative to positive. [0037] In preferred embodiments, the analysis used for threshold calculations is based on Filtered_WF data using either of two methods: (1) Using the difference between the Filtered_WF peak values determined in step 42 and the Filtered_WF values associated with the “base” value of Deriv>0_WF found in step 44 . This difference is referred to as “Max_Diff” (step 46 ). (2) Using the Filtered_WF peak values associated with the Deriv>0_WF values found in step 42 . This value is referred to as “Max Value” (step 48 ). [0040] The ratio of the CF values found in steps 40 and 20 is expressed as: [0000] Adj / Filter_CF  _RMS = ( Adj_Deriv > 0  _CF  _RMS ) ( Filtered_WF  _CF  _RMS ) . ( step   50 ) [0000] If Adj/Filter_CF_RMS is greater than or equal to three (step 52 ) and no maximum peaks were discarded in Deriv>0_WF (step 53 ), then the Deriv>0_WF waveform is used as the signal from which tachometer pulses are derived. The tachometer signal threshold (step 54 ) is calculated from the Deriv>0_WF waveform. If maximum peaks were discarded in Deriv>0_WF (step 53 ), then a “bad data” indication is generated (step 55 ). If Adj/Filter_CF_RMS is less than three (step 52 ), then the Filtered_WF waveform is used to create tachometer pulses and as a basis to set the tachometer signal threshold (step 56 ). Whichever waveform is used to set the threshold is referred to herein as the “decision WF.” [0041] Calculation of Threshold Value [0042] The set of amplitudes (values) of the decision WF used to calculate the threshold limit are preferably within μ±2σ, where the mean and standard deviation are calculated from the set of values used in calculating Max_Diff and Max_Value (steps 46 and 48 ). Details of a statistical method for discarding data outside the limits is described hereinafter (Method 3 with n=2). [0043] For calculations related to Max_Diff: [0000] Max_Threshold=MaxΔ+Base Value (step 58); and [0000] Min_Threshold=MinΔ+Base Value (step 60) [0000] where Δ=change (difference value) from the peak in the Filtered_WF waveform and the closest left-most base value; and Base value=amplitude value at a position in the Filtered_WF waveform where the slope changes from≦zero to positive. Min_Threshold can be greater than Max_Threshold because the MaxΔ value could have a small base value compared to MinΔ which could have an associated large base value. [0046] For calculations related to Max_Value: [0000] Max_Threshold=Amplitude of the largest peak taken from the sorted “N” peaks extracted from Filtered_WF (step 36) with Base Value=0 (step 62); and [0000] Min_Threshold=Amplitude of the smallest peak taken from the sorted “N” peaks extracted from the Filtered_WF (step 36) with Base Value=0 (step 64). [0047] Calculation of the Percent Difference Threshold (referred to herein as %_Diff_Threshold) indicates how much the difference between two values change from the average: [0000] Percent   Difference   Threshold = ( Max_Threshold ) - ( Min_Threshold ) ( ( Max_Threshold ) + ( Min_Threshold ) 2 ) . ( step   66 ) [0048] The Percent Mean Filtered Max Peak (referred to herein as %_Mean_Fltd_Max_PK) is the percent change in the amplitude values of the maximum peaks in the Filtered_WF data: [0000] %  _Mean  _Fltd  _Max  _PK = [ 1 - ( μ - σ μ ) ] * 100  % . ( step   68 ) [0000] This parameter is the percent mean taken from the “N” maximum peaks of the Filtered_WF data, where N is either a user-selected number of peaks or is calculated as described hereinafter in a process that calculates the number of peaks for analysis. The mean and standard deviation are calculated for the set of maximum peak values taken from the Filtered_WF data. [0049] If %_Mean_Fltd_Max_PK from step 68 is larger than ten, then the data is considered “questionable.” This means the data “jumps” around too much and it is difficult, if not impossible, to set a realistic threshold. A threshold can still be calculated but will probably not be useful. [0050] As shown in FIG. 3 , if Adj/Filter_CF_RMS from step 50 is less than three (step 52 ) and no peaks were discarded from the statistical analysis of the maximum peaks in Deriv>0_WF (step 70 ), then the method proceeds to evaluate the magnitude of %_Mean_Fltd_Max_PK determined in step 68 . If %_Mean_Fltd_Max_PK is less than or equal to ten (which means Max_Threshold and Min_Threshold are reasonably close in value) (step 72 ), then: [0000] Thrsh10=Min(Max_Threshold and Min_Threshold)−2*(|Max_Threshold−Min_Threshold|)(step 74). [0000] If %_Mean_Fltd_Max_PK is greater than ten (step 72), then: [0000] Thrsh10=Min(Max Threshold and Min Threshold)−(|Max Threshold−Min Threshold|)(step 76) [0000] and the method proceeds to step 78 . [0051] If %_Diff_Threshold (calculated at step 68 ) is greater than 40 (step 78 ), then [0000] Threshold = Mid_Threshold = ( Threshold_multiplier ) * ( Max_Threshold + Min_Threshold ) 2 [0000] where Threshold_multiplier is a user-selectable value between 0 and 1 (step 80 ). In preferred embodiments, the value used is 1. If %_Diff_Threshold (calculated at step 68 ) is less than or equal to 40 (step 78 ), then the method proceeds to step 82 . [0052] If %_Mean_Fltd_Max_PK is greater than or equal to 0.5 (step 82 ), then [0000] Threshold=Thrsh10 (step 84). [0000] If %_Mean_Fltd_Max_PK is less than 0.5 (step 82 ), then [0000] Threshold=0.67*Min(Max_Threshold and Min_Threshold) (step 86). [0000] Generally, %_Mean_Fltd_Max_PK is less than 0.5 when data is very steady and the values of the peaks are all about the same amplitude. [0053] Referring back to step 52 of FIG. 3 , if Adj/Filter_CF_RMS is less than three and peaks were discarded from the statistical analysis of the maximum peaks in Deriv>0_WF (step 70 ), then the method proceeds to step 88 . If %_Diff_Threshold is less than or equal to 40 (step 88 ), then [0000] Threshold=0.5×MinΔ+Min_base_value (step 90). [0000] If %_Diff_Threshold is greater than 40 (step 88 ), then [0000] Threshold=Min_Threshold (step 92). [0000] It should be noted that if peaks are discarded, then there are peaks in the original “number of peaks for analysis” which are statistical outliers (values greater than μ±nσ). [0054] Referring again to step 52 of FIG. 3 , if Adj/Filter_CF_RMS is greater than or equal to three and no peaks were discarded from statistical analysis of the maximum peaks in Deriv>0_WF, then the Deriv>0_WF waveform is used as the tachometer signal and to set the threshold (step 54 ) according to: [0000] Threshold=μ+2σ (step 94) [0000] where μ and σ are calculated from the N peaks of the Deriv>0_WF waveform. [0055] Tables 1 and 2 provide a summary of the threshold calculation. [0000] TABLE 1 Data Calculations Calculations to determine Threshold Filtered_WF_CF_RMS (step 20) Deriv_CF_RMS (step 24) Deriv > 0_CF_RMS Equivalent Equivalent Equivalent Values Values Values Differ (step 34) Value Value Value Differ Differ Adj_Deriv > 0_CF_RMS (step 40) Adj_Deriv > 0  _CF  _RMS Filtered_WF  _CF  _RMS ( step   52 )   ≧3 <3 ≧3 <3 Percent Difference ≦40% >40% ≦40% >40% Threshold (step 88) Threshold Value μ + 2σ for See Table 2. Mid_Threshold Bad Data 0.5*MinΔ + Min_Threshold Deriv > 0_WF Base Value [0000] TABLE 2 Percent Mean Filtered Max Peak Threshold Value <0.5 0.67 * Min(Max_Threshold and Min_Threshold) ≧0.5 and ≦10 Min of (Max_Threshold and Min_Threshold) − 2*(|Max_Threshold − Min_Threshold|) >10 Min(Max_Threshold and Min_Threshold) − (|Max_Threshold − Min_Threshold|) [0056] Method to Determine the Number (N) of Peaks for Analysis [0057] Following is a preferred embodiment of a routine for determining the number of largest peaks in a given waveform necessary to effectively evaluate data for determination of a threshold level. To calculate the number peaks (N) for analysis: [0000] If (Filter_WF_Kurtosis > Deriv_CF_RMS) AND   (Deriv>0_CF_RMS > Deriv_CF_RMS) AND   (Deriv>0_CF_RMS > Filter_WF_Kurtosis) THEN   Peak Multiplier = 1.5 Else   Peak Multiplier = 0.75 Endif   N = [Integer value (rounded up) of ((Peak Multiplier) × (Cycles of RPM))] where:  Filter_WF_Kurtosis is the kurtosis of the filtered waveform. Kurtosis is an indication of the    shape of the distribution of data. A value of 3 represents a normal distribution.    Values less than 3 indicate flatter distributions. Values greater than 3 indicate a    sharper (more narrow) distribution. Deriv_CF_RMS is the crest factor calculated from the waveform produced by taking the    derivative of the filtered waveform (Deriv_WF) as calculated above in step 24. Deriv>0_CF_RMS is the crest factor calculated form the waveform produced from derivative    values greater than zero (Deriv>0_WF) as calculated above in step 34. Peak Multiplier is the value used to scale the final number of peaks for analysis. Cycles of RPM is the number of RPM cycles present in a given waveform, calculated as:    Cycles of RPM = Sampling Rate (sec) × (Rated Speed (RPM) / 60) [0058] Methods for Sorting Out Statistical Outliers [0059] The following routine takes an array of data values and discards values outside the statistically calculated boundaries. In a preferred embodiment, there are four methods or criteria for setting the boundaries. [0060] Method 1: Non-Conservative, Using Minimum and Maximum Statistical Boundaries [0061] Consider an array of P values (or elements) where P 0 represents the number of values in the present array under evaluation. Now let P −1 represent the number of values in the array evaluated a single step before P 0 , let P −2 represent the number of values in the array evaluated a single step before P −1 , and let P −3 represent the number of values in the array evaluated a single step before P −2 . [0062] Step 1: [0000] While evaluating the array of values for either the first time or P 0 ≠ P −1 ,  {  Calculate the mean (μ) and standard deviation (σ) for P 0   If   n   σ μ ≥ 0.1 , then   ( n = 1 , 2   or   3 )   Include array values such that   μ − nσ < values < μ + nσ  Else   STOP, values are within statistical boundaries.  Endif  } [0063] Step 2: [0000]   If P 0 = P −1 , then  While P −1 ≠ P −2 , and P 0 = P −1   {   Calculate the mean (μ) and standard deviation (σ) for P 0    If   n   σ 2  μ ≥ 0.1 , then   ( n = 1 , 2   or   3 )  Include   array   values   such   that  μ - n   σ 2 < values < μ + n   σ 2     Else    STOP, values are within statistical boundaries.   Endif   }  Endif [0064] Step 3: [0000] If P 0 = P −1 = P −2 , and P −2 ≠ P −3 , then   Calculate the mean (μ) and standard deviation (σ) for P 0   Include array values such that   0.9μ < values < 1.1μ Else   STOP, values are within statistical boundaries. Endif [0065] Method 2: Non-Conservative, Using Maximum Statistical Boundary Only (No Minimum Boundary) [0066] Use the same procedure as in Method 1 except only values exceeding the upper statistical boundaries are discarded. The minimum boundary is set to zero. [0067] Method 3: Conservative, Using Minimum and Maximum Statistical Boundaries [0068] Discard values based on Method 1, Step 1 only. [0069] Method 4: Conservative, Using Maximum Statistical Boundary Only (No Minimum Boundary) [0070] Discard values based on Method 1, Step 1 only and based on values exceeding the upper statistical boundaries. The minimum boundary is set to zero. [0071] Example of Method 1 for Sorting Out Statistical Outliers [0072] As an example of the sorting Method 1, consider an original set of values, P 0 , containing the 21 values listed below in Table 3 below, with n=1. [0000] TABLE 3 0.953709 0.828080 0.716699 0.653514 0.612785 0.582031 0.579209 0.557367 0.545801 0.495215 0.486426 0.486053 0.475123 0.472348 0.467129 0.465488 0.446327 0.440497 0.437959 0.427256 0.411627 [0073] The mean (μ) of this original set, P 0 , is 0.54955 and standard deviation (σ) is 0.13982. Therefore, in Step 1 of Method 1, [0000] n   σ μ = 1 * 0.13982 0.54955 = 0.25442 . [0000] Since 0.25442 is greater than 0.1, calculate [0000] μ− nσ= 0.54955−1*0.13982=0.409735 [0000] and [0000] ν+ nσ= 0.54955+1*0.13982=0.689373. [0074] Next, define the set P −1 =P 0 and define a new set P 0 , the values of which are all the values of P −1 that are between the values μ+σ=0.689343 and μ−σ=0.409735. The set P 0 now contains the values listed below in Table 4, wherein three outlier values have been eliminated. [0000] TABLE 4 0.653514 0.612785 0.582031 0.579209 0.557367 0.545801 0.495215 0.486426 0.486053 0.475123 0.472348 0.467129 0.465488 0.446327 0.440497 0.437959 0.427256 0.411627 [0075] Since P 0 ≠P −1 , Step 1 is repeated, where for the set P 0 : [0000] μ=0.50234, [0000] σ=0.06946, [0000] σ/μ=0.138263, [0000] μ+σ=0.571797, and [0000] μ−σ=0.432887. [0076] Now define the set P −2 =P −1 , and P −1 =P 0 and define a new set P 0 , the values of which are all the values of P −1 that are between the values μ+σ=0.571797 and μ−σ=0.432887. The set P 0 now contains the values listed below in Table 5, wherein four more outlier values have been eliminated. [0000] TABLE 5 0.557367 0.545801 0.495215 0.486426 0.486053 0.475123 0.472348 0.467129 0.465488 0.446327 0.440497 0.437959 0.427256 0.411627 [0077] Since P 0 ≠P −1 , Step 1 is repeated, where for the set P 0 : [0000] μ=0.472473, [0000] σ=0.041332, and [0000] σ/μ=0.087481. [0000] Since [0000] σ/μ=0.087481≦1, [0000] all the members of the array P 0 are statistically close in value and need no more sorting. [0078] If at any point in the calculations P 0 =P −1 and P −1 ≠P −2 , then Step 2 would be executed instead of Step 1. In the example above, since P 0 ≠P −1 for every iteration, only Step 1 was necessary for the calculations. [0079] The foregoing description of preferred embodiments for this invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the invention and its practical application, and to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

A method is described for automatically determining a proper threshold for a tachometer signal in order to produce desired tachometer pulses necessary for analysis of machine vibration data. A tachometer signal is low-pass filtered to exclude high frequency noise and a running derivative of the filtered tachometer waveform is taken to create a derivative waveform. Another waveform is created that includes only positive values from the derivative waveform that correspond to positive values in the low-pass filtered tachometer waveform. In general, a tachometer signal has the greatest derivative value (slope) when a tachometer pulse is present. Based on this observation, a threshold value is determined using both the low-pass filtered tachometer waveform and the positive-value derivative waveform along with statistics from both waveforms.

CROSS-REFERENCE TO RELATED APPLICATION This application is the U.S. national phase of PCT Appln. No. PCT/EP2007/061825 filed Nov. 2, 2007 which claims priority to German application DE 10 2006 053 157.4 filed Nov. 10, 2006. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a process for evaporating constituents of a liquid by passing alternating current through the liquid. 2. Description of the Related Art In the process technology sector, it has been known for some time that, for an efficient heat transfer via hot surfaces, the temperature difference between heating surface and liquid to be heated must be at a maximum. However, problems arise when pursuing this maximum in the case of heating of liquids comprising gaseous and/or low-boiling components. When the surface temperature exceeds a critical temperature difference from the boiling point of the low-boiling component, a vapor film thus forms at the heating surface, which thermally insulates the liquid from the heating surface and therefore worsens the heat flow. This phenomenon is known as the “Leidenfrost phenomenon”. The necessary introduction of heat into the liquid in such cases can therefore be achieved only by increasing the heat exchange area. On the other hand, however, such an increase in the heating surface area is impossible or very expensive owing to the nature of the apparatus and process prerequisites. Alkylchlorosilanes are prepared by the route of the so-called direct synthesis from Si and MeCl. This affords a complex mixture of different alkylchlorosilanes with different boiling points. The target product is dichlorodimethylsilane with a boiling point of 71° C. (1013 mbar). In the distillative recovery of the pure alkylchlorosilanes from the product mixture obtainable by the direct synthesis, distillation residues with a boiling point of >71° C. are obtained. These are complex substance mixtures which contain compounds with SiSi, SiOSi, SiCSi, SiCCSi and SiCCCSi structures. The composition of these so-called “high boilers” is described in detail, for example, in EP 0 635 510. As a result of the raw material or of the selective addition of catalytically active constituents, not only Si, but also further impurities of Cu, Zn, Sn, Al, Fe, Ca, Mn, Ti, Mg, Ni, Cr, B, P and C are found in the product stream of the direct synthesis. The impurities are present in suspended or dissolved form. The dissolved impurities are usually chlorides. To heat the distillation residues, according to the prior art, for example, circulation evaporators, thin-film evaporators, short-path evaporators or heat exchangers are used. After removal of the lower-boiling components, in which the above problems exist in heat transfer, however, the thermal stability of the liquid constituents still present decreases under the influence of heat, and in the presence of the suspended or dissolved impurities. This results in oligomerization and polymerization reactions. The viscosities of the mixtures increase. This results in deposition of undesired deposits in pipelines, and in particular on the hot surfaces of the evaporators employed. Mass and energy transfer is increasingly hindered. Owing to heat transfer which has been reduced as a result, the surface temperature of the evaporator surfaces has to be increased further, which in turn leads to accelerated coverage thereof. As a result, the apparatus has to be cleaned often, the distillate yield falls, and the plant availability is unsatisfactory. A disadvantage of the above-described prior art processes is the principle of heat introduction. Heat is transferred to the liquid silanes via hot surfaces, for example metals or graphite, which are in turn heated by heat carriers (steam, heat carrier oil) or electrical heating elements. In the case of this type of heat transfer, the surface temperature of the heat-transferring medium must be higher than the liquid to be heated. These higher surface temperatures are the cause of the problems described. SUMMARY OF THE INVENTION The invention provides a process for evaporating constituents of a liquid which comprises constituents A which have high boiling points and do not boil at 1013 mbar, and constituents B which are gaseous at 20° C. and 1013 mbar and boil at least 30 K lower than the high-boiling constituents A, at least one constituent being at least partly dissociated to ions, wherein the liquid is heated by passing alternating current through it. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates one embodiment of an apparatus suitable for carrying out the process of the invention in plan view. FIG. 2 is a process flow diagram for one embodiment of the inventive process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS When electrically conductive liquids comprising gaseous and/or low-boiling components are heated by alternating current, virtually all of the energy in the liquid is utilized for heating, because no thermally insulating vapor film hinders heat transfer. The surfaces of the vessels and pipelines remain free of deposits. The heating and evaporation temperature may be regulated very rapidly and within narrow tolerances, since no heat transfer via hot surfaces is present. In the event of interruption of the liquid stream, no overheating of the liquid by hot surfaces is to be expected, and the introduction of heat can be interrupted abruptly by switching off the alternating current supply. The electrical field generated by the alternating current causes charge carriers to vibrate, which heats the liquid. A previously nonconductive liquid can be made electrically conductive by adding suitable salts, such that the desired heating occurs when an alternating voltage is applied. The high-boiling and nonboiling constituents A may be partly or fully dissociated to ions, i.e. may be electrically conductive, or nonconductive. When the high-boiling and non-boiling constituents A are nonconductive, the constituents B must be electrically conductive. Examples of electrically conductive constituents B are gaseous and low-boiling acids, such as formic acid, acetic acid, hydrochloric acid, nitric acid, and gaseous and low-boiling bases, such as trimethylamine, triethylamine and ammonia. The constituents B preferably boil at least 40 K lower than the high boiling constituents A, more preferably 50 K lower than the high-boiling constituents A. The alternating voltage is preferably at least 10 V, more preferably at least 50 V and most preferably at most 1000 V. The frequency of the alternating current is at least 10 Hz, preferably at least 30 Hz, more preferably at most 10,000 Hz, and most preferably at most 10,000 Hz. Alternating current also includes three-phase current. The specific electrical resistivity of liquid is preferably from 10 10 Ωm to 10 6 Ωm, more preferably from 10 9 Ωm to 10 8 Ωm. The process can be performed continuously or batchwise. A preferred apparatus for the process is constructed as follows: the liquid is at rest or circulates within a tubelike heater composed of two or more tubes one inside another, which function as electrodes. The electrical alternating current is applied to the electrodes. The intermediate space of the tubes which are preferably in a rotationally symmetric arrangement is filled by the liquid, which is heated by the alternating current. The two or more internal tubes are separated by an electrical insulation and are connected to one another in an outwardly liquid-tight manner. The materials of the electrodes must be electrically conductive and may, for example, be metals or graphite. In a preferred embodiment, the electrically conductive fractions of an alkyl chlorosilane distillation, such as the above-described distillation residues from the direct synthesis of methylchlorosilanes with a boiling point of >71° C., are heated by passing alternating current through them. Owing to the impurities present, these have a sufficient electrical conductivity. Values of the specific electrical resistivity of from 1.10 9 Ωm to 10.10 7 Ωm are determined. The constituents which have been dissociated to ions remain in the bottoms of the evaporator in the case of a distillation, or are discharged continuously via the bottom effluent, and do not influence the quality of the distillates. In a further preferred embodiment, the electrically conductive reaction mixtures of chlorosilanes and ethanol or methanol are heated and evaporated or outgassed by means of passage of alternating current. In a further preferred embodiment, the electrically conductive reaction mixture is prepared from chlorosilanes, such as tetrachlorosilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane or mixtures thereof, and an aqueous or nonaqueous alcohol, such as ethanol or methanol, by means of passage of alternating current. The conversion of the reaction can be completed only by driving out the HCl gas which forms in the reaction by increasing the temperature. Since this mixture is saturated with HCl, a thermally insulating gas layer is formed at the interface thereof in the case of heating by means of a heat exchanger. Heating by means of alternating current avoids this problem and allows inexpensive heating which is very effective based on the space requirement, since the heat is generated directly in the liquid volume and need not be transported over a large interface of a heat exchanger. In the example which follows, unless stated otherwise, a) all amounts are based on the mass; b) all pressures are 0.10 MPa (abs.); c) all temperatures are 20° C. Example The example is illustrated by FIG. 1 , which shows a heating and evaporating apparatus as a section view. In this apparatus, the liquid ( 5 ) enters the heating and evaporating apparatus from below, and the liquid is heated in the intermediate space ( 4 ) and exits again at the top as heated liquid or as vapor ( 6 ). Between the electrodes ( 1 ) and ( 2 ) which are in a rotationally symmetric arrangement flows an electrical alternating current. The electrodes ( 1 ) and ( 2 ) are separated from one another by an electrical insulation ( 3 ). The electrodes ( 1 ) and ( 2 ) are installed in a vertical glass vessel ( 10 ). The vapor is passed into a column with random packing ( 9 ), while an overflow of liquid is recirculated through conduit 11 to the vessel. The isolating transformer ( 7 ) and the flow regulator unit ( 8 ) feed the electrodes ( 1 ) and ( 2 ) with regulable electrical energy. Technical data of the heating and evaporating apparatus: electrode material: Cr, Ni steel length of the electrode ( 1 ): 200 mm diameter of the electrode ( 1 ): 50 mm diameter of the electrode ( 2 ): 30 mm electrode separation ( 4 ): 10 mm liquid volume: 700 ml Test results: start of the evaporation test: temperature of the liquid in the inlet ( 5 ) 30° C. temperature of the liquid in the vessel ( 4 ) 30° C. voltage: 240 V, frequency: 50 Hz, current: 0.3 A specific electrical resistivity: 4.5×10 9 Ωm temperature (vapor) at the outlet ( 6 ) 30° C. temperature of the electrodes ( 1 ) and ( 2 ): 30° C. during the continuous evaporating operation: temperature of the liquid in the inlet ( 5 ) 30° C. voltage: 240 V, frequency: 50 Hz, current: 0.3 A temperature of the liquid in the vessel ( 4 ) 220° C. specific electrical resistivity: 4.5×10 8 Ωm temperature (vapor) at the outlet ( 6 ): 190° C. temperature of the electrodes ( 1 ) and ( 2 ): 220° C. After operation for 50 h, the surfaces of the electrodes ( 1 ) and ( 2 ) exhibited neither any deposition nor any encrustation, nor was any abrasion of the electrode material evident.

Mixtures containing high boiling and low boiling components, at least one component being dissociatable into ions, are separated effectively by heating by passing an alternating electrical current through the mixture. The process is particularly effective in the workup of crude alkylchlorosilanes from the direct synthesis.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a method and system for creating a personalized display for a user of an electronic network. More specifically, the present invention relates to a method and system for determining a user's interests from the content of electronic documents viewed by the user and providing recommended documents and recommendation packages to a user based upon the determined interests. 2. Description of Related Art The number of Internet users continues to increase at an explosive rate. The World Wide Web (“Web”) has therefore now become a significant source of information, as well as products and services. As the numbers of Web users rise, Internet commerce, also referred to as “e-commerce” companies, and content providers are increasingly searching for strategies to target their information, products and services to those Web users. One technique that is currently being used to provide Web users with more relevant and timely information is “personalization.” Personalization can include sending a user an e-mail message tailored to that user, or providing customized Web pages that display information selected by, or considered of interest to the user. Personal merchandising, in which a unique view of an online store, featuring offerings targeted by customer profile is displayed, is another effective personalization technique. Personalization facilitates the targeting of relevant data to a select audience and can be a critical factor in determining the financial success of a Web site. Internet companies wishing to create highly personalized sites are currently poorly served by both personalization technology vendors and customer relationship marketing product vendors. Each of these vendors offers only part of the overall solution. In addition, a significant investment of time and resources by the client is required to deploy these current solutions. Most prior art personalization and Web user behavior (also known as clickstream) analysis technologies maintain a record of select Web pages that are viewed by users. This record, known as the “Web log” records which users looked at which Web pages in the site. A typical Web log entry includes some form of user identifier, such as an IP address, a cookie ID or a session ID, as well as the Uniform Resource Locator (“URL”) the user requested, e.g. “index.html.” Additional information such as the time the user requested the page or the page from which the user linked to the current Web page can also be stored in the Web log. Traditionally, such data has been collected in the file system of a Web server and analyzed using software, such as that sold by WebTrends and Andromedia. These analyses produce charts displaying information such as the number of page requests per day or the most visited pages. No analysis is performed of the internal Web page structure or content. Rather, this software relies on simple aggregations and summarizations of page requests. The prior art personalization methods also rely on the use of Web logs. One technology used in prior art personalization methods is the trend analysis method known as collaborative filtering. Examples of collaborative filtering systems are those of Net Perceptions (used for Amazon.com's book recommendations), Microsoft's Firefly, Personify, Inc., and HNC Software Inc.'s eHNC. One method of collaborative filtering is trend analysis. In trend analysis collaborative filtering, the pages requested by a user are noted, and other users that have made similar requests are identified. Additional Web pages that these other users have requested are then recommended to the user. For example, if User A bought books 1 and 2 from an on-line bookseller, a collaborative filtering system would find other users who had also bought books 1 and 2 . The collaborative filtering system locates 10 other users who on average also bought books 3 or 4 . Based upon this information, books 3 and 4 would be recommended to User A. Another type of collaborative filtering asks the users to rank their interest in a document or product. The answers to the questions form a user profile. The documents or products viewed by other users with a similar user profile are then recommended to the user. Systems using this technique include Reel.com's recommendation system. However, collaborative filtering is not an effective strategy for personalizing dynamic content. As an example, each auction of a Web-based auction site is new and therefore there is no logged history of previous users to which the collaborative filtering can be applied. In addition, collaborative filtering is not very effective for use with infrequently viewed pages or infrequently purchased products. Another technique used to personalize Internet content is to ask the users to rank their interests in a document. Recommendations are then made by finding documents similar in proximity and in content to those in which the user has indicated interest. These systems may use an artificial intelligence technique called incremental learning to update and improve the recommendations based on further user feedback. Systems using this technique include SiteHelper (Ngu and Wu, 1997), Syskill & Webert (Pazzani et al., 1996) Fab (Balabanovic, 1997), Libra (Mooney, 1998) and Web Watcher (Armstrong et al., 1995). Another technique that has been used to personalize Internet content is link analysis. Link analysis is used by such systems as the search engine Direct Hit and Amazon.com's Alexa®. The prior art link analysis systems are similar to the trend analysis collaborative filtering systems discussed previously. In the link analysis systems, however, the URL of a web page is used as the basis for determining user recommendations. Other prior art personalization methods use content analysis to derive inferences about a user's interests. One such content analysis system is distributed by the Vignette Corporation. In the content analysis method, pages on a client's Web site are tagged with descriptive keywords. These tags permit the content analysis system to track the Web page viewing history of each user of the Web site. A list of keywords associated with the user is then obtained by determining the most frequently occurring keywords from the user's history. The content analysis system searches for pages that have the same keywords for recommendation to the user. This prior art content analysis systems is subject to several disadvantages. First, tagging each page on the client's Web site requires human intervention. This process is time-consuming and subject to human error. The prior art content analysis systems can only offer recommendations from predefined categories. Furthermore, the prior art content analysis systems require a user to visit the client's Web site several times before sufficient data has been obtained to perform an analysis of the user's Web page viewing history. Other prior art content analysis systems automatically parse the current document and represent it as a bag of words. The systems then search for other similar documents and recommend the located documents to the user. Such systems include Letizia (Lieberman, 1995) and Remembrance Agent (Rhodes, 1995). These content analysis systems base their recommendations only on the current document. The content of the documents in the user's viewing history are not used. Many Web sites offer configurable start pages for their users. Examples of configurable start pages include My Yahoo! and My Excite. To personalize a start page using the prior art method, the user fills in a form describing the user's interests. The user also selects areas of interest from predefined categories. The user's personalized start page is then configured to display recommendations such as Web pages and content-based information that match the selected categories. This prior art method, however, is not automated. Rather, the user's active participation is required to generate the personalized Web start page. Furthermore, pages on the client's Web site must be tagged to be available as a recommendation to the user. In addition, recommendations can only be offered from predefined categories. Thus, the prior art personalized start pages may not provide relevant content to users who have eclectic interests or who are not aware of or motivated to actively create a personalized start page. Content Web sites are increasingly generating income by using advertising directed at users of the Web sites. In the prior art, advertising was targeted to users by using title keywords. In this method, keywords in the title of a Web page or otherwise specified by the author of the page are compared with the keywords specified for a particular advertisement. Another technique used is to associate specific ads with categories in a Web site. For example, advertisements for toys might be associated with Web site categories related to parenting. However, these prior art methods require human intervention to select the keywords or to determine the associations of advertisements with particular categories. Furthermore, the prior art methods cannot readily be used to target advertisements to dynamic content. It would therefore be an advantage to provide a method and system for providing Internet end users with relevant and timely information that is rapid to deploy, easy and inexpensive for client Web sites to use. It would be a further advantage if such method and system were available to automatically and dynamically determine the interests of a user and recommend relevant content to the user. It would be yet another advantage if such method and system were available to provide for a user a personalized recommendation package, such as an automatically generated start page for each user who visits a Web site. SUMMARY OF THE INVENTION One embodiment of the present invention provides a computer-implemented method for creating a personalized display of electronic-mail documents. The method includes creating a database entry including a user ID for each user of a client document server, the document server being coupled to an electronic-mail client. Requests for access to an e-mail document at the client document server are then tracked by a tracking module. Information regarding the request document is then stored, the information including information about the document that is obtained through textual analysis of the requested document. The stored information is then analyzed to construct a profile of the user requesting the document; that profile is then associated with the user ID. From the profile, interests of the user are determined utilizing a recommendation application. The user is then provided with electronic-mail notifications concerning recommended viewing of additional documents on the document server, The recommendations are based on the determined interests of a particular user. In another embodiment of the present invention, a method for automated analysis of electronic-mail documents is provided. The method includes a user viewing a document at a client document server, the document server being coupled to an electronic-mail client. Internal content information from the viewed document is transmitted to a recommendation application, which generates recommendation links in response to the transmitted content information. A further embodiment of the present invention provides an electronic-mail document analysis method. Through this method, internal content information of an e- mail document accessed by a user is received. Themes and concepts of the document are then determined. The document is then grouped into a folder on the client document server according to the themes and concepts; the document server being coupled to an electronic-mail client. Keywords are extracted from the documents in the folders to allow for summarization of the folder. A profile is then developed corresponding to a particular user and based on the themes and concepts of the folder. Utilizing this profile, personalized recommendations are generated with respect to viewing additional e-mail documents on the server. In yet another embodiment of the present invention, a method is disclosed for customizing electronic-mail document information provided over an electronic network. In this method, requests by a user of a client document server for e-mail documents are tracked, Filtered content is extracted from the requested e-mail documents and analyzed. A profile is then constructed based on the analyzed content and a profile is developed. Based on the profile, interests of the user are determined and the user is provided with subsequent information as to e-mail documents for review by the user. An embodiment of the present invention also provides a system for creating a personalized display of electronic-mail documents. The system includes means for: tracking requests by a user of a client document server for a document on the client document server; extracting filtered content from the requested document; analyzing the filtered content; constructing a profile of the user from the analyzed content determining the interests of the user; and providing the user with recommended information by email based upon the determined interests of the user. A further embodiment of the present invention provides a system for providing personalized electronic-mail document information including an e-mail client coupled to a computing device. A processor in the system executes software instructions to extract filtered content a viewed document; analyze the filtered content determine a theme or concept of the document cluster the document into a folder according to a theme or concept in the document; construct a profile of the user from the analyzed content; determine the interests of the user based on the user profile; categorize a second document according to the theme or concept of the folder; and recommend that the user access the second categorized document, the recommendation being based on the theme or concept of the second document. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow diagram of the personalization method according to the present invention FIG. 2 is a block diagram of a computer network system according to one embodiment of the present invention. FIG. 3 is a diagram of the system for Internet personalization, according to the preferred embodiment of the invention. FIG. 4 is a flow chart of the method for Internet personalization, according to the preferred embodiment of the invention FIG. 5 is a flow chart illustrating the formation of interest folders, according to the present invention. FIG. 6 is an example of a user profile generated by the recommendation software, according to the preferred embodiment of the present invention. FIG. 7 is an example of a recommendation start page according to the preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention is a computer-implemented method and system for creating a personalized display for a user of an electronic network. The method can be used with any electronic network including the Internet and, more specifically, the World Wide Web. The preferred embodiment of the present invention includes components for analyzing Web user behavior, for remote user tracking, and for interacting with the user. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one skilled in the art that the present invention may be practiced without the specific details. In other instances, well-known structures and devices are shown in block diagram form to facilitate explanation. The description of preferred embodiments is not intended to limit the scope of the claims appended hereto. Features of the Invention: The present invention provides a user personalization service to businesses and organizations that provide document servers. In the preferred embodiment, the invention is directed primarily to e-commerce and Internet businesses. The invention can be used to provide personalization and Web user behavior (referred to herein as “clickstream”) analysis. This service enables e-commerce and Internet sites to deliver highly personalized and relevant information to each of their users. The invention can be used with, but is not limited to, content sites and e-commerce sites. FIG. 1 is a flow diagram of the personalization method according to the present invention. The invention uses the recommendation software to remotely collect and process end user behavior 100 . Each user action is considered and analyzed in terms of the structural content of the document that is actually viewed by the user 105 . The interests of the user are determined 110 and the user can thereby be provided with a list of recommended documents that are selected according to the analysis of the content of the documents viewed by the user 115 . In addition, the invention can also be used to generate a personalized recommendation package, such as, in the preferred embodiment, a personalized start page or a personalized product catalogue for each user. The present invention is advantageous because, by having more relevant information delivered to each end user, the client can draw users back to the client document server and can create a barrier to their switching to a competing document server. This can result in increased advertising revenue accruing to the client, and e-commerce clients can receive more revenue from sales because each user will receive more relevant suggestions of products to buy and will return more regularly. The invention offers significant advantages to clients over the prior art personalization methods. For example, using the invention, a personalized recommendation package can be rapidly deployed, with minimal effect on the original client document server during deployment. The present invention avoids the requirement for clients to develop and invest in complex techniques for their own tracking and personalization and is therefore more economical than prior art personalization schemes. In addition, the present invention will enable clients to retain customers through improved one-to-one interaction as well as drive revenue from increased sales through cross-selling and up-selling of their products. Definitions: For purposes of this application, the present invention will be referred to as the “recommendation system”. The use of the term recommendation system is in no way intended to limit the scope of the present invention as claimed herein. As described in further detail herein, the recommendation system can include any suitable and well-known hardware and software components, and in any well-known configuration to enable the implementation of the present invention. The present invention is also implemented using one or more software applications that are accessible to the recommendation system. For purposes of this application, these software applications will be called the “recommendation software.” The use of the term recommendation software is in no way intended to limit the scope of the present invention as claimed herein. The personalization service according to the present invention is preferably provided by an entity, referred to for purposes of this application as the market analyst. The term “client,” as used herein, refers to the operator of a document server. In the preferred embodiment of the present invention, the client is the operator/owner of a Web site. The term “user” refers herein to an individual or individuals who view a document served by the client's document server. The recommendation system can include the market analyst's computers and network system, as well as any software applications resident thereon or accessible thereto. For purposes of this application, these components will be collectively referred to as the “marketing system.” The use of the term marketing system is in no way intended to limit the scope of the present invention as claimed herein. As described herein, the marketing system can include any suitable and well-known hardware and software components, and in any well-known configuration to enable the implementation of the present invention. In the presently preferred embodiment, the marketing system is maintained separately from the client document server. However, in alternative embodiments, the hardware and software components necessary to provide the personalization service can be a part of the client document server. In these alternative embodiments, the hardware and software components can be operated by, for example, a client e-commerce or Internet business itself. The client's computers and network system, as well as any software applications resident thereon or accessible thereto will be collectively referred to, for purposes of this application, as the “document server.” The term “document” is used to represent the display viewed by a user. In a Web-based embodiment, the document is a Web page. In an e-mail embodiment, the document can be an e-mail message or listing of messages, such as an in-box. As used herein, the term “database” refers to a collection of information stored on one or more storage devices accessible to the recommendation system and recommendation software, as described previously. The use of the term database is in no way intended to limit the scope of the present invention as claimed herein. The database according to the present invention can include one or more separate, interrelated, distributed, networked, hierarchical, and relational databases. For example, in the presently preferred embodiment of the invention, the database comprises a document database and a user database. The database can be created and addressed using any well-known software applications such as the Oracle 8™ database. The database according to the present invention can be stored on any appropriate storage device, including but not limited to a hard drive, CD-ROM, DVD, magnetic tape, optical drive, programmable memory device, and Flash RAM. The term “content sites” refers to Internet sites that are primarily providers of content based information such as news articles. Examples of content Web sites include CNET, MSN Sidewalk, and Red Herring. These sites can generate income from advertising, as well as syndication or referral fees for content. A content site's income can therefore be greatly dependent upon the Web site's ability to retain users. E-commerce sites are Internet sites whose primary business is the sale of goods or services. E-commerce businesses derive revenue from the sale of goods on their Web sites. A significant factor in the success of an e-commerce Web site is the site's ability to attract and retain customers. Syndicated content, as used herein, refers to other publisher's content that can be integrated into a client's document server. Hardware Implementation: Any or all of the hardware configurations of the present invention can be implemented by one skilled in the art using well known hardware components. In the presently preferred embodiment, the present invention is implemented using a computer. Such computer can include but is not limited to a personal computer, network computer, network server computer, dumb terminal, local area network, wide area network, personal digital assistant, work station, minicomputer, and mainframe computer. The identification, search and/or comparison features of the present invention can be implemented as one or more software applications, software modules, firmware such as a programmable ROM or EEPROM, hardware such as an application-specific integrated circuit (“ASIC”), or any combination of the above. FIG. 2 is a block diagram of a computer network system 200 according to one embodiment of the present invention. Any or all components of the recommendation system, the marketing system, the client document server, and the user's computer can be implemented using such a network system. In computer network system 200 , at least one client document server computer 204 is connected to at least one user computer 202 and to at least one marketing system computer 212 through a network 210 . The network interface between computers 202 , 204 , 212 can also include one or more routers, such as routers 206 , 208 , 214 that serve to buffer and route the data transmitted between the computers. Network 210 may be the Internet, a Wide Area Network (WAN), a Local Area Network (LAN), or any combination thereof. In one embodiment of the present invention, the client document server computer 204 is a World-Wide Web (“Web”) server that stores data in the form of ‘Web pages’ and transmits these pages as Hypertext Markup Language (HTML) files over the Internet network 210 to user computer 202 . Similarly, the marketing system computer can also be a WWW server. Communication among computers 202 , 204 , 212 can be implemented through Web-based communication. In some embodiments of the present invention, computers 202 , 204 , and 212 can also communicate by other means, including but not limited to e-mail. It should be noted that a network that implements embodiments of the present invention may include any number of computers and networks. Software Implementation: Any or all of the software applications of the present invention can be implemented by one skilled in the art using well known programming techniques and commercially available or proprietary software applications. The preferred embodiment of the present invention is implemented using an Apache Web server and Web-based communication. However, one skilled in the art will recognize that many of the steps of the invention can be accomplished by alternative methods, such as by e-mail. In the preferred embodiment of the invention, the operating system for the marketing system is Red Hat™ Linux™. However, any other suitable operating system can be used, including but not limited to Linux™, Microsoft Windows 98/95/NT, and Apple OS. The recommendation software can include but is not limited to a Web server application for designing and maintaining the market analyst's Web site, a database application for creating and addressing the database, software filters for screening the content of documents served by the client's document server, a text clustering application, a text categorization program, a presentation module, a spider and/or search engine for seeking relevant documents, an e-mail application for communication with users, a spread sheet application, and a business application for verifying orders, credit card numbers, and eligibility of customers. The recommendation software can include any combination of interrelated applications, separate applications, software modules, plug-in components, intelligent agents, cookies, JavaBeans™, and Java™ applets. (Java and all Java-based marks are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries.) The software applications that comprise the recommendation software can be stored on any storage device accessible to the marketing system, including but not limited to a hard drive, CD-ROM, DVD, magnetic tape, optical drive, programmable memory device, and Flash RAM. It will be readily apparent to one of skill in the art that the software applications can be stored on the same or different storage devices. In the preferred embodiment of the invention, the clustering application is implemented using the C programming language. However, in alternative embodiments, the clustering application can be implemented using other well-known programming languages, including but not limited to C++, Pascal, Java, and Fortran. The clustering application is preferably stored on the marketing system, but can alternatively be stored on any component accessible to the marketing system. In the preferred embodiment of the invention, the presentation module is implemented using Perl scripts and SQL. However, in alternative embodiments, the presentation module can be implemented in any other suitable programming language. The presentation module is preferably stored on the marketing system, but can alternatively be stored on any component accessible to the marketing system. In the preferred embodiment of the invention, the tracking module that is associated with the client's document server is implemented using Perl scripts. However, in alternative embodiments, the tracking module can be implemented using other well-known programming languages and software applications including but not limited to TCL, Java™ servlet, and Microsoft Active Server Page (“ASP”) applications. The tracking module is preferably stored on the client's document server, but can alternatively be stored on any component accessible to the document server. In the preferred embodiment of the present invention, content analysis and the generation of the user profiles, recommendations, and recommendation packages are all performed by the marketing system and recommendation software. However, in alternative embodiments of the present invention, any or all of these functions can also be performed by the client document server. The client document server performs the functions of data collection, data transfer to the marketing system and presentation of the recommendations and recommendation packages to the user. In the preferred embodiment of the invention, the database is implemented using Data Konsult AB's MySQL. However, in alternative embodiments, the tracking module can be implemented using other software applications including but not limited to Postgres, and Oracle® and Informix® database applications. The database is preferably stored on the marketing system server, but can alternatively be stored on any component accessible to the marketing system. The recommendation software is preferably a separate application from the marketing system operating system. However, one skilled in the art will readily recognize that the present invention can also be fully integrated into the marketing system operating system. DESCRIPTION OF THE EMBODIMENTS FIG. 3 is a diagram of the system 300 for Internet personalization, according to the preferred embodiment of the invention. A tracking module 306 is installed at the client document server 304 . In the presently preferred embodiment, a Web site manager embeds Hypertext Markup Language (“HTML”) links to the marketing system in the client document server and, specifically, on the client document server's start page. While the tracking module is implemented as a Perl module embedded in Apache in the preferred embodiment, the tracking can alternatively be implemented in other ways, for example using hypertext links. At the client document server 304 , the tracking module logs every request made by every user for documents and sends this information to the database 310 associated with the marketing system 308 . In the preferred embodiment of the present invention, the database 310 includes a document database module 312 for storing information relating to the document and contents of the document, and a user database module 314 for storing information relating to the user's document viewing behavior. In the preferred embodiment, each user is sent a user-identifier (“user ID”) 316 that is stored on the user's computer 302 . The tracking module sends the user ID and a document identifier (“document ID”) 318 to the marketing system 308 in response to each user's request to view a document on the client document server 304 . The recommendation software 320 is then used to process this information to construct a profile for the user and to make recommendations based thereupon. In the preferred embodiment, the presentation module 322 is operable to configure a recommendation package for the user into any desired format or appearance. FIG. 4 is a flow chart of the method for Internet personalization, according to the preferred embodiment of the invention. A tracking module is installed at a client document server. In the preferred embodiment of the present invention, the client document server is a Web site. However, in alternative embodiments, the present invention is implemented with a client e-mail or File Transfer Protocol (“ftp”) system. In this preferred embodiment, when a user requests a document on the client document server 400 , the tracking module searches for a user ID on the user's computer 405 . If a user ID is not located, the tracking module creates a new entry in the database and sends a user ID to the user's computer 410 . In the preferred embodiment, this involves sending a cookie to the user's Web browser. However, any other appropriate identifier can alternatively be used, such as an IP number. The tracking module installed at the client document server logs every request made by every user for documents and sends this information to the marketing system. Thus, when the user requests a different document in the client's document server, the tracking module logs this action by sending the user ID and a document identifier (“document ID”) to the database 415 . In the presently preferred embodiment, the document ID is the URL of the particular Web page. However, other document IDs such as a product number can also be used. In alternative embodiments of the present invention, the tracking module can send additional information, such as the time spent viewing a document and the price of items displayed on the document to the marketing system database. The subsequent actions on the client document server of any user who is entered in the marketing system database are similarly recorded in the marketing system database. In yet another embodiment of the present invention, the marketing system can act as a proxy server. In this embodiment, the tracking module could be installed at either the marketing system or the client document server, or at both. In this embodiment, the user requests documents from the marketing system. In response to such request, the marketing system requests the appropriate documents from the client document server and provides them to the user. In the preferred embodiment, documents and meta-data about the documents are stored in the document database module of the database. The document database can include other information obtained from the client, such as the price or size of an item. The user database module can include information obtained from the user, for example, whether the user placed a bid on an item, the user's name and address, which documents were viewed by the user, whether the user purchased an item, user profile or the time the user spent viewing a particular document. Information obtained from text analysis, document clustering, or document categorization can also be stored in the user database module. As the user browses through the client's document server, the marketing system uses the recommendation software to process the user's behavior, analyze the content of the user's document views and construct a profile for the user 420 . The recommendation software uses the information in the user database to make a determination of what interests the particular user. For example a user who browsed an auction Web site for antique Roman coins and baseball cards would be determined to have two interests. These interests are determined by an analysis of the actual content of each browsed document. The recommendation software uses any or all of the gathered information about the user to search through the content on the client's document server to find the local content considered most relevant to that particular user 425 . In the preferred embodiment of the invention, the marketing system regularly retrieves the content for each document and/or product on the client document server, for example, once per hour. The recommendation software analyzes each document a user views in terms of the (a) content and (b) ancillary information related to a user's viewing a document. The present invention uses this analysis of document content to provide a model for automatically deriving reasonable inferences regarding a user's interests and intentions in viewing particular documents. This model can then be used to generate a list of additional documents on the client document server, or elsewhere such as on another document server, that might be of interest to the user. These “recommendation documents” and “recommendation packages” provide a suggested product and/or document that is tailored to a user's interests and to the product and/or document that a user is currently viewing. The marketing system sends the recommended document(s), or a link to the recommended document(s) back to the client's document server 430 . The recommendations can include but are not limited to URLs, product numbers, advertisements, products, animations, graphic displays, sound files, and applets that are selected, based on the user profile, to be interesting and relevant to the user. For example, the most relevant ad for any page can be rapidly determined by comparing the current user profile with the description of the available advertisements. The user recommendations can be provided as a part of a personalized recommendation package. In the preferred embodiment of the invention, the recommendation package is a personalized Web start page for the user. For an e-mail server-based embodiment, the recommendation package can be personalized e-mail. The recommendation package gives each end user a unique view of the client document server by showing information that is relevant to that user. In the preferred embodiment, the document displayed to the user by the client document server includes a hypertext link that is used to access the personalized Web start page. When the user clicks on the hypertext link, the personalized start page is dynamically generated by the recommendation software at the marketing system. Each user will see a different view of the Web site based on the user's personal likes or dislikes, as determined automatically by the user's previous browsing behavior. Such automatic personalization minimizes the need for the client to specifically control document server content and permits the client to transparently provide information regarding the user's interests. When the user clicks on a link to this personalized Web page on the client's document server, the personalized page is served to the user from the marketing system. Although the page is served from the marketing system, the presentation module is operable to configure the personalized page to conform to the client's own branding and image, thereby maintaining the look and feel of the client's site. In addition, the Uniform Resource Locator (“URL”) link, which is the “Web address” of the personalized page is configured to appear to be a link to the client document server. In alternative embodiments of the present invention, the personalized Web page does not have to maintain the look and feel of the client's document server, but can have any desired appearance. In such embodiments, the presentation module is operable to configure the recommendation package into any desired format or appearance. Furthermore, there is no requirement that URL link provided to the user appear to link the Web page to any particular Web site. In one embodiment of the present invention, the user can switch back at any time to the from the personalized recommendation package, such as the personalized Web start page, to a non-personalized document, such as the generic start page of displayed by the client document server. In another embodiment of the invention, portions of the client's document server can be mirrored on the marketing system. The recommendation software can then search through the mirrored client document server for content relevant to the particular user. The recommendation software can also optionally include syndicated content from the marketing system or from the client's syndication providers in the personalized page. New standards based on XML such as Information Content Exchange (“ICE”) will facilitate the incorporation of syndication into Web sites. The recommendation software according to the present invention uses information regarding the client's document server structure in the personalization analysis. For example, if a user typically looks at books in a particular category of a bookseller's Web site, this information will be used by the recommendation software, in addition to any content information, to create a personalized view of the site for the user. FIG. 5 is a flow chart illustrating the formation of interest folders, according to the present invention. The recommendation software thereby extracts and organizes the interests and document viewing habits of the user. In the preferred embodiment of the invention, the recommendation software uses a statistical process referred to herein as document clustering to group together those documents of the client document server that have been viewed by the user according to their common themes and concepts. For each individual user, the recommendation software clusters those documents that have the most themes and concepts in common with one another into interest folders 505 . In the preferred embodiment, the recommendation software continually monitors each user and continually updates the user's interest folders and profile. The set of interest folders for each user can also be used to target advertisements to each user rather than, or in addition to content. In the presently preferred embodiment, each advertisement has an associated simple description. This description is specified by the creator of the ad. The description can be associated with the advertisement by methods including embedding in meta-language tags or in XML. Document clustering according to the present invention includes the automatic organization of documents into the most intrinsically similar groups or segments. As an example of the application of using document clustering, a user who enters the search term “Venus” into a search engine will likely receive documents about (a) Venus the planet; and (b) Venus the goddess. In the preferred embodiment of the present invention, the search results would therefore be clustered accordingly into two separate interest folders. None of the concepts in groups (a) and (b) are predefined but are formed as a result of the intrinsic similarity of the documents in each cluster. As a result, the clustering framework is very flexible for automatic organization of documents into groups. In the preferred embodiment of the present invention, the recommendation software uses a proprietary clustering algorithm to form the user interest folders. The clustering algorithm uses the textual content of the documents viewed by a user, in combination with structural information about the document server, and ancillary information about the user to determine the interest folders for a user. In an alternative embodiment, a clustering algorithm is also used to segment large numbers of users into different user folders. However, one skilled in the art would readily recognize that any other suitable clustering algorithm could also be used in alternative embodiments of the invention. One significant feature of the clustering algorithm used by the invention is that the output of the algorithm can be readily viewed and understood. Each document cluster (interest folder) is described by the most relevant keywords of the documents within the document cluster 510 . This feature enables both users and marketers to understand and control the degree of personalization and targeting that is made. The recommendation software can also be used to categorize documents 515 . Document categorization is the automatic placement of new documents into existing predefined categories. Document categorization is used in the preferred embodiment of the present invention to select, from a database, documents that match a user's interest folders. A document categorizer can learn how to place new documents into the correct categories so that, for example, a new Web page or product can be automatically placed into the correct user interest folder. As an example, given a user interest folder containing documents about Roman coins, a document categorizer could select the most relevant products for that user from a particular Web site. Because Web pages are diverse in structure and form, the recommendation software uses customizable filters that extract only the content deemed to be relevant to users. In addition to extracting the content of each page, the recommendation software uses filters to extract structure within this content. The present invention can also use adaptive filtering algorithms that analyze a Web site and review different filter known structures to automatically find an appropriate filter for a particular Web site. For example, an on-line bookseller's Web page can display information regarding a book that is available for purchase. The Web page can include such structure as: book price, author, description, and reviews. The fields of the document database are preferably customized to the bookseller's Web page such that the names of each of these fields can automatically be stored therein. The fields of the user database are similarly configured for automatic storage of information obtained from the user. This information is then included in the recommendation software's analysis. In the preferred embodiment of the invention, the recommendation software uses proprietary filters that are specific for each Web site. For example, each of two music distribution Web sites would have its own specific customized filter. Alternatively, the recommendation software can use filters that are specific for different types of Web sites. As an example, the recommendation software can have separate specific filters for such sites as auction Web sites, bookseller Web sites, and music Web sites. One skilled in the art would recognize that the recommendation software can also use any suitable commercially available filters. In the preferred embodiment, each interest folder is automatically summarized in terms of the most relevant keywords from the associated collection of pages in the folder. Keywords can be determined, for example, by using an information theoretic measure such as “Minimum Message Length” (“MML”) to determine the most relevant words to define a user's interest folder. Filters, such as the removal of “stopwords,” can be used to screen out common prepositions, articles, possessives, and irrelevant nouns, adjectives, etc. The keywords for a user's interest folders can be determined in any appropriate manner. In one embodiment of the invention, the message length of sending each word using the population frequency of the word is determined. This message length is referred to herein as the population message length of the word. The message length of sending each word using the interest folder's frequency of the word is then determined. This message length is termed herein the interest folder message length of the word. For each keyword, the interest folder message length of that keyword is then subtracted from the population message length of the word. The keywords for the user's interest folders are defined to be the words in which this distance is the greatest. FIG. 6 is an example of a user profile 600 generated by the recommendation software, according to the preferred embodiment of the present invention. The profile shown in the personalized Web page of FIG. 6 comprises two different interest folders 602 , 604 for a user of an on-line auction Web site. Each interest folder contains pages which are intrinsically similar to one another and dissimilar to pages in other interest folders. A specific interest folder contains a set of links 610 to auctions the user has viewed that are related to the theme of the interest folder. An interest folder can also include additional information including but not limited to information regarding the history of the user's Internet viewing, recommendations for the user, a summary of the user's purchases. In the example illustrated in FIG. 6 , each interest folder also has an associated set of keywords 612 that summarize the most important concepts of the particular interest folder, as determined by the recommendation software. In the preferred embodiment of the present invention, the user can display and edit the user profile of FIG. 6 . For example, if the user is no longer interested in Roman antiquities, this interest folder 612 can be deleted from the user profile. It is common for a user to regularly return to particular Web sites to look for specific information having a similar theme. For example, a user of an on-line auction Web site who collects Roman coins might frequently return to the antiquities section of the auction Web site. The present invention uses the profile of each user to automatically find other relevant pages in the Web site to recommend to the user. In the previous example, the recommendation software would search through all of the auctions currently running on the on-line auction Web site to search for those that match most closely with each of the user's interest folders. The present invention uses a sophisticated search engine that can incorporate any or all of the content and ancillary information in the user profile. FIG. 7 is an example of a recommendation start page 700 according to the preferred embodiment of the present invention. The user's interest folders 602 , 604 are displayed on the recommendation document. Each interest folder includes links to documents 610 that the recommendation software has selected based upon the user's profile. In the previous example of the Roman coin collector, the folder relating to this interest 604 includes links to auctions for Roman and other ancient coins. In the preferred embodiment of the present invention, a user can view and manage the user's profile. Thus, in the previous example, the user may wish to remove certain sections of the profile in order to stop receiving recommendations about Roman coin auctions. The recommendation software user interface allows users to delete interest folders, add extra keywords to an interest folder, or create their own interest folder from pages on a client document server. Because the user profiles are based primarily on keywords, the present invention can be used to not only target a user with content from the same Web site that the user is currently browsing, but also with content from other Web sites. For example, a user with an interest in collecting Roman coins could be automatically targeted with content from on-line publications related to antiquities. While the present invention is designed to automatically match users with relevant content, it is recognized that a client might wish to customize the manner in which users receive special promotions, event announcements and special news items. In the example of the Roman coin collector, a marketer of cruises might wish to target the collector with a promotion for a cruise of the Mediterranean. To enable marketers to interact easily with their users, the present invention provides the functionality to allow a marketer to search through the users' profiles using keywords in a standard search paradigm. Groups of users can be selected and then matched with relevant content either by hand or automatically using the present invention's content matching technology. While the invention is described in conjunction with the preferred embodiments, this description is not intended in any way as a limitation to the scope of the invention. Modifications, changes, and variations which are apparent to those skilled in the art can be made in the arrangement, operation and details of construction of the invention disclosed herein without departing from the spirit and scope of the invention. One skilled in the art will readily recognize that, in an embodiment that features Web-based interaction between the user, the market analyst, and the marketer, there are many different ways in which communication can be implemented through the Web page graphical user interface. For example, this communication can be implemented using elements including but not limited to a dialog box, check box, combo box, command button, list box, group box, slider bar, text box. In the preferred embodiment of the present invention, all client's and users use computer-implemented methods to interact with the market analyst, for example, using a Web page or e-mail. However, in alternative embodiments, one or more such customers can communicate with the market analyst using other methods of communication, including but not limited to telephone, fax, and mail. For example, in one embodiment, a user can request modifications to the user's profile by making a telephone call to a client or to the market analyst.

Systems and methods for providing a user with personalized recommendations of accessing electronic-mail at an electronic-mail document server are provided. Recommendations may be based on determined interests of the user based on the theme or concept of a previously categorized document, the previously categorized document having been previously accessed by the user.

FIELD OF THE INVENTION The present invention relates to a thin film transistor, and more particularly to a low-temperature polysilicon thin film transistor having a lightly doped drain (LDD) structure. The present invention also relates to a process for producing a thin film transistor. BACKGROUND OF THE INVENTION TFTs (Thin Film Transistors) are widely used as basic electronic devices for controlling pixels of a TFT liquid crystal display (TFTLCD). FIG. 1( a ) is a block diagram schematically illustrating a conventional TFTLCD. Such TFTLCD comprises an active matrix 10 and driving circuits 11 . The active matrix 10 is formed on a glass substrate 1 , whereas the driving circuits 11 are electrically connected to the active matrix 10 via external lines 12 . Nowadays, a so-called low-temperature polysilicon thin film transistor (LTPS-TFT) technology was developed due to improved electrical properties of TFT transistors and other benefits. Please refer to FIG. 1( b ). The active matrix 10 and the driving circuits 11 can be directly formed on the glass substrate 1 so as to reduce fabricating cost. A process for producing such LTPS-TFT is illustrated with reference to FIGS. 2( a ) to 2 ( f ). In FIG. 2( a ), a polysilicon layer 21 is formed on a glass substrate 2 by laser annealing an amorphous silicon layer applied to the glass substrate 2 at a low temperature, and patterning and etching the annealed silicon layer. Then, as shown in FIG. 2( b ), a photoresist 22 is formed on a selected region of the polysilicon layer 21 , and an ion-implantation procedure is performed on the resulting polysilicon layer 21 with the photoresist 22 serving as a mask. By the ion-implantation procedure, B + ions are implanted to form N-channel TFT zones. Then, a photoresist 23 is partially formed on the N-channel TFT zones, and PHx + ions are implanted into the N-channel TFT zones with the photoresist 23 serving as a mask, thereby forming source/drain regions 24 , as can be seen in FIG. 2( c ). After the photoresists 22 and 23 are removed, a gate insulator 25 is formed on the resulting structure. Then, gate metal 26 (for example made of molybdenum) is formed on the gate insulator 25 , as shown in FIG. 2( d ). The gate metal 26 for each N-channel TFT zone has cross-sectional area less than that of the corresponding photoresist 23 for that N-channel TFT zone formed in the previous step shown in FIG. 2( c ). Then, for N-channel TFT zones, lightly doped drain (LDD) regions 241 are formed by implanting P + ions with the gate metal 26 as a mask. The N-channel TFT zones are covered with a photoresist 27 , and then another ion implantation procedure is performed on the resulting structure with the photoresist 27 serving as a mask to form a P-channel TFT zone, as shown in FIG. 2( e ). The dopants are B 2 Hx + ions, and source/drain regions 242 are formed. Afterwards, an interlayer dielectric layer 28 and source/drain conductive lines 29 are formed in sequence, as shown in FIG. 2( f ), to obtain the desired LTPS-TFT structure. With the increasing development of integrated circuits, electronic devices have a tendency toward miniaturization. As a result of miniaturization, the channel between the source and drain regions in each TFT will become narrower and narrower. A so-called “hot electron effect” is rendered, which impairs stability of the LTPS-TFT and results in current leakage. The LDD regions are useful to reduce the hot electron effect. Conventionally, a process involving many masks and steps are involved in order to form the LDD regions. Another conventional process of forming LDD regions by a self-aligned procedure would involve reduced masking steps. For the self-aligned procedure, the LDD regions do not overlap with the gate metal 26 thereabove. It is found, however, improved device stability will be obtained when the gate metal 26 extends over the LDD region 241 to a certain extent. Unfortunately, there is likely to be parasitic capacitance occurring in the overlapped region between the gate metal 26 and the LDD region 241 , which adversely causes a voltage drift of the storage capacitor and liquid crystal capacitor in a pixel cell when the pixel is turned off. SUMMARY OF THE INVENTION It is an object of the present invention to provide a TFTLCD having an LDD region with satisfying stability and minimized voltage drift. According to a first aspect of the present invention, a thin film transistor display comprises a driving circuit comprising a first thin film transistor structure. The first thin film transistor structure comprises a first gate, source and drain regions, a first LDD region, a second LDD region and a first channel region between the first and the second LDD regions. The first gate region is disposed over the first channel region and overlaps with the first and the second LDD regions. An active matrix is controlled by the driving circuit and comprises a second thin film transistor structure. The second thin film transistor structure comprises a second gate, source and drain regions, a third LDD region, a fourth LDD region and a second channel region between the third and the fourth LDD regions. The second gate region is disposed over the second channel region and overlaps with neither of the first and the second LDD regions. Preferably, the length of the first gate region is greater than the length of the first channel region. Preferably, the length of the second gate region is no greater than the length of the second channel region. More preferably, the length of the second gate region is identical to the length of the second channel region. Preferably, the active matrix and the driving circuit are formed on the same substrate, e.g. a glass substrate. Preferably, the display is a liquid crystal display. Preferably, the thin film transistor display further comprises a passivation layer overlying the first and the second thin film transistor structures; and a plurality of contact plugs extending from the source/drain regions, respectively. According to a second aspect of the present invention relates to a process for producing a thin film transistor display. The process includes steps of providing a substrate; forming a polysilicon layer on the substrate; patterning the polysilicon layer to define a first and a second TFT regions; providing a first and a second doping masks on the polysilicon layer in the first and the second TFT regions to result in a first exposed portion in the first TFT region and a second exposed portion in the second TFT region; implanting a first doping material into the first and the second exposed portions, thereby defining a first doped region and a first channel region adjacent to the first doped region in the first TFT region, and a second doped region and a second channel region adjacent to the second doped region in the second TFT region; removing the first doping mask; providing a third doping mask on the first channel region, which partially overlies the first doped region, so as to result in a third exposed portion in the first TFT region smaller than the first exposed portion; implanting a second doping material into the third exposed portions to form first source/drain regions and simultaneously define a first LDD region; removing the second and the third doping masks; forming an insulator layer and a gate metal layer on the resulting structure; and patterning the gate metal layer to form a first and a second gate structures over the first and the second channel regions, respectively. The first gate structure is longer than the first channel, and the second gate structure has length smaller than or substantially equal to the second channel region. In one embodiment, the process further comprises a step of implanting a third doping material into the second TFT region with the second gate structure serving as a doping mask to form second source/drain regions and a second LDD region. In one embodiment, the process further comprises a step of covering a portion of the patterned polysilicon layer with a fourth doping mask before doping the patterned polysilicon layer for further defining a third TFT region. In one embodiment, the first TFT region is an N-channel TFT region of a driving circuit, the second TFT region is an N-channel TFT region of an active matrix, and the third TFT region is a P-channel TFT region. Preferably, the fourth doping mask is removed along with the second and the third doping masks. In one embodiment, the process further comprises steps of: forming a third gate structure over the third TFT region at the same time when the first and the second gate structures are formed; and implanting a third doping material into the third TFT region with the third gate region serving as a mask to form source/drain regions of the third TFT region. The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1( a ) is a block diagram schematically illustrating a conventional TFTLCD; FIG. 1( b ) is a block diagram schematically illustrating a conventional LTPS-TFTLCD; FIGS. 2( a ) to 2 ( f ) are schematic cross-sectional views illustrating a conventional process for producing an LTPS-TFTLCD having LDD regions; FIG. 3 is a schematic cross-sectional view illustrating the structure of an LTPS-TFTLCD according to a preferred embodiment of the present invention; FIGS. 4( a ) to 4 ( g ) are schematic cross-sectional views illustrating a process for producing an LTPS-TFTLCD having LDD regions according to a preferred embodiment of the present invention; and FIGS. 5( a ) to 5 ( f ) are schematic cross-sectional views illustrating a process for producing a CMOS thin film transistor according to a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As previously described, the fabricating cost of a low-temperature polysilicon thin film transistor liquid crystal display (LTPS-TFTLCD) is relatively low because the active matrix and the driving circuit are formed on the same glass substrate. In addition, the LTPS-TFTLCD has reduced hot electron effect due to the presence of an LDD region. When the LDD region and the gate metal of the LTPS-TFTLCD overlap with each other, i.e. the gate metal of the LTPS-TFTLCD, an improved device stability is obtained while accompanied by some adverse effects such as current leakage and parasitic capacitance. Therefore, voltage drift of the storage capacitor and liquid crystal capacitor in a pixel cell is caused. As is known, the thin film transistors in the active matrix and the driving circuit perform different functions and thus have different requirements. For example, the thin film transistor in the active matrix requires accurate voltage levels. On the contrary, good device stability is prerequisite for the thin film transistor in the driving circuit. Based on the above concept, a specified LTPS-TFTLCD is developed according to the present invention, as can be seen in FIG. 3 . The LTPS-TFTLCD comprises a driving circuit portion and an active matrix portion, which are formed on the same substrate 3 . In the driving circuit portion, an N-channel TFT M 1 and a P-channel TFT M 2 are included. In the active matrix portion, N-channel TFTs M 3 are included. The N-channel TFT M 1 comprises a gate structure 31 , source/drain regions 32 , LDD regions 33 and a channel region 34 . According to the present invention, the gate region 31 disposed over the channel region 34 overlaps with the LDD regions 33 in order to assure of good device stability. On the other hand, the thin film transistor structure M 3 , which comprises a gate structure 35 , source/drain regions 36 , LDD regions 37 and a channel region 38 , has the gate structure 35 thereof substantially staggered with the LDD regions 37 . In other words, the gate structure 35 does not overlap with the LDD regions 37 so as to reduce current leakage and parasitic capacitance. A process for producing an LTPS-TFT similar to that of FIG. 3 according a preferred embodiment of the present invention is illustrated with reference to FIGS. 4( a ) to 4 ( g ). In FIG. 4( a ), a polysilicon layer 41 is formed on a glass substrate 4 by laser annealing an amorphous silicon layer applied to the glass substrate 4 at low temperature, and patterning and etching the annealed silicon layer. Then, as shown in FIG. 4( b ), a photoresist 42 is formed on a selected region R 2 of the polysilicon layer 41 , which is defined as a P-channel TFT zone, and an ion-implantation procedure is performed on the resulting polysilicon layer 41 with the photoresist 42 serving as a mask. By the ion-implantation procedure, B + ions are implanted to form N-channel TFT zones in regions R 1 and R 3 . Then, photoresists 431 and 432 are formed on the N-channel TFT zones in the active matrix portion and the driving circuit portion, respectively, and PHx + ions are implanted into the exposed parts of the N-channel TFT zones with the photoresist 431 and 432 serving as masks, thereby defining source/drain regions 44 , as can be seen in FIG. 4( c ). Meanwhile, the channel region 442 of the N-channel TFT zone in the region R 1 , is defined. Afterwards, the photoresist 431 is removed and replaced by a photoresist 433 having greater as-shown cross-sectional length than the photoresist 431 . As shown in FIG. 4( d ), PHx + ions are continuously implanted into the N-channel TFT zones in the regions R 1 and R 3 with the photoresist 433 and 432 serving as masks, thereby forming heavily doped source/drain regions 440 and 442 for all the N-channel TFT zones in the regions R 1 and R 3 and LDD regions 441 for the N-channel TFT zone in the region R 1 . After the photoresists 42 , 432 and 433 are removed, a gate insulator layer 45 is formed on the resulting structure. Then, a gate metal layer (for example made of molybdenum) is formed on the gate insulator 45 , and the gate metal layer is patterned to form gate structures 461 , 462 and 463 . As shown in FIG. 4( e ), the gate structure 461 has cross-sectional length substantially the same as that of the photoresist 433 having been removed previously, and thus the gate structure 461 has length greater than the channel region 442 . On the other hand, the gate structure 463 has cross-sectional length less than that of the corresponding photoresist 432 having been removed in the previous step shown in FIG. 4( d ). Then, PHx + ions are continuously implanted with the gate metal structures 461 , 462 and 463 serving as masks in the regions R 1 , R 2 and R 3 , respectively, thereby defining source/drain regions 444 in the region R 2 , and forming LDD regions 445 for the N-channel TFT zones in the region R 3 of active matrix portion, as can be seen in FIG. 4( e ). Meanwhile, the channel region 446 of the N-channel TFT zone in the region R 3 is defined. In this embodiment, the gate structure 463 has length substantially identical to that of the channel region 446 . Depending on various processes, however, the present structure still works if the gate structure 463 is shorter than the channel region 446 . The N-channel TFT zones in the regions R 1 and R 3 are then covered with a photoresist 47 , and then another ion implantation procedure is performed on the resulting structure with the photoresist 47 serving as a mask so as to form a P-channel TFT zone in the region R 2 , as shown in FIG. 4( f ). The dopants are B 2 Hx + ions, and source/drain regions 446 are formed. Afterwards, an interlayer dielectric layer 48 and source/drain conductive lines 49 are formed, as shown in FIG. 4( g ), according to any proper technique, so as to obtain the desired LTPS-TFT structure. That is, the gate electrode 461 of the N-channel TFT in the driving circuit portion overlies the LDD regions 441 to exhibit good device stability, and the effect of the possible parasitic capacitance on a driving circuit is insignificant. On the other hand, the gate electrode 463 and the LDD regions 445 of the N-channel TFT in the active matrix portion stagger from each other to prevent from the voltage level drift resulting from current leakage and parasitic capacitance. The concept of the present invention can also be applied to produce a complimentary metal oxide semiconductor (CMOS) thin film transistor. The process will be illustrated with reference to FIGS. 5( a ) to 5 ( f ). In FIG. 5( a ), a polysilicon layer 51 is formed on a glass substrate 5 by laser annealing an amorphous silicon layer applied to the glass substrate 4 at low temperature, and patterning and etching the annealed silicon layer, thereby defining a first and a second TFT regions R 1 and R 2 to serve as an N-channel TFT zone and a P-channel TFT zone, respectively. Then, as shown in FIG. 5( b ), a photoresist 52 is formed on the polysilicon layer 51 in the N-channel TFT zone R 1 , and an ion-implantation procedure is performed on the resulting polysilicon layer 51 with the photoresist 52 serving as a mask. By the ion-implantation procedure, B + ions are implanted into the polysilicon layer 51 in the N-channel TFT zone R 1 . Then, as shown in FIG. 5( c ), a photoresist 53 is partially formed on the polysilicon layer 51 in the N-channel TFT zone R 1 , and PHx + ions are implanted into the polysilicon layer 51 in the N-channel TFT zone R 1 with the photoresist 53 serving as a mask. After the photoresists 52 and 53 are removed, a gate insulator 55 is formed on the resulting structure. Then, a gate metal layer (for example made of molybdenum) is formed on the gate insulator 55 , and the gate metal layer is patterned to form gate structures 561 and 562 , as shown in FIG. 5( d ). The gate structure 561 has cross-sectional length substantially the same as that of the polysilicon layer 51 in the N-channel TFT zone R 1 . Another ion implantation procedure is performed on the resulting structure with the gate structure 562 serving as a mask in the P-channel TFT zone R 2 . The dopants are B 2 Hx + ions, and source/drain regions 54 are formed. Then, the gate structure 561 is removed and replaced by another gate region 563 having cross-sectional length smaller than the gate structure 561 but greater than the channel region 510 of the polysilicon layer 51 . Preferably but not necessarily, the length of the gate structure 563 is equal to the total length of the channel region 510 plus the LDD regions 591 , as shown in FIG. 5( e ). Then, a photoresist 57 is formed on the gate region 563 , and the P-channel TFT zone is covered with a photoresist 58 . Then, PHx + ions are implanted into the N-channel TFT zone with the photoresist 57 serving as a mask, thereby forming source/drain regions 59 and LDD regions 591 in the N-channel TFT zone R 1 . Afterwards, an interlayer dielectric layer 60 and source/drain conductive lines 61 are formed, as shown in FIG. 5( f ), to obtain the desired CMOS structure. From the above description, it is known that the process for fabricating the TFTLCD having an LDD region is performed without increasing masking steps when compared with the conventional self-aligned procedure. Advantageously, the TFTLCD fabricated according to the present invention has an LDD region and a gate metal overlapped with each other so as to achieve good device stability. While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.

A thin film transistor display includes a driving circuit and an active matrix. The driving circuit comprises a first thin film transistor structure. The first thin film transistor structure includes a first gate, source and drain regions, a first LDD region, a second LDD region and a first channel region between the first and the second LDD regions. The first gate region is disposed over the first channel region, and partially or completely overlies the first and the second LDD regions. The active matrix is controlled by the driving circuit and comprises a second thin film transistor structure. The second thin film transistor structure includes a second gate, source and drain regions, a third LDD region, a fourth LDD region and a second channel region between the third and the fourth LDD regions. The second gate region is disposed over the second channel region and substantially overlaps with neither of the first and the second LDD regions.

BACKGROUND OF THE INVENTION (1) Field of the Invention The present invention relates to a laser-scanning microscope with sample illumination and detector means, which for the purpose of image acquisition illuminates and detects a sample in a raster scanning manner, with a real-time control device. The control device controls the illumination and detector means for illumination and detection and reads out detection signals, whereby the control device performs control and readout synchronously with a pixel cycle that determines the raster scanning. A data port is connected between the control device and the illumination and detector means and communicates with the control device via a parallel, bidirectional data stream and with the illumination and detector means via a serial, bidirectional high-speed data stream and for this reason performs a conversion of data from parallel into serial or vice versa. The invention further relates to a laser scanning microscope with sample illumination and detector means, which for purposes of image acquisition illuminate and detect a sample by raster scanning, with a real-time control device, which controls the illumination and detector means for illumination and detection and reads out detection signals. A control device controls the illumination and detection and reads out the detection signals synchronously with a pixel cycle that determines the raster scanning, a data port, connected between the control device and the illumination and detector means, communicates with the control device via a parallel, bidirectional data stream and with the illumination and detector means via a serial, bidirectional high-speed data stream and for this purpose performs a conversion of data from parallel into serial or vice versa. In a laser scanning microscope of this type, as is offered, for example, by Carl Zeiss AG under the designation LSM 510, image acquisition is carried out by exciting and scanning a sample pixel-by-pixel with excitation or illumination radiation. The image comes about by the intensity of radiation being allocated to the appropriate pixel coordinates and in this way coalescing into an image. Consequently, a pixel-synchronous matching of illumination and detector means, particularly of a scanner, i.e., of a deflecting device is required for illumination and detection in order to gather the information for the image. This implies that the highest data transmission rate possible should be used in the control as well as the readout of it since the speed and volume of the data transmission automatically impacts the length of time that is needed for imaging. Especially with biological samples, it would be desirable, though, to obtain an image as fast as possible, for example, to be able to analyze biological processes. At the same time, this is not only dependent on the data rate, i.e., the product of the data packet size and transmission frequency, but also on the reaction speed at which communication proceeds between the real-time control device and the illumination and detector means. The transmission frequency is a determining factor for this. Here it must also be borne in mind that not only the control of the deflecting device or the illumination units, e.g., lasers, etc., has to be carried out in a pixel-synchronous way, but rather that today's highly sensitive detector means require equally to a certain extent complex control for readout of the intensity of radiation to be allocated to the pixels. Photomultiplier tubes (PMTs) requiring among other things control of the radiation integration procedures and readout processes are cited as an example. For each pixel, data has to be transmitted to the PMT and data also has to be read out by the PMT. In the final analysis, therefore, an effort is being made to design the data communication so fast that it is not the time determinant in the operation chain. This implies that the data communication should be fast enough in order to process the data traffic needed for this within the minimum time that is needed for detection of a pixel's radiation by the detector (which is called the pixel time). For high-speed data communication different approaches, which however either need substantial device-related time and effort or have insufficient speed attainment, are familiar in data processing technology. (2) Summary of the Invention Therefore, the present invention's basic function is to refine a microscope or technique of the type designated at the beginning in such a way that control of the illumination and detector means is achieved with little time and effort. At the same time, the data rate attained allows for transmitting the data required for each pixel within the pixel time specified on the detector side. According to the invention this function is performed with a laser-scanning microscope of the designated type, in which the high-speed data stream from the illumination and detector means to the data port is made up of data packets with data bits and type bits and with no additional header or protocol bits. The data bits contain the data on the illumination and detector means and the type bits code the type of data. In the illumination and detector means, if need be, also in the control device, type information is stored that defines processing functions for data types coded by means of the type bits, and when sending, the illumination and detector means set the type bits for the data types in a type assessment. The function is performed further with a technique of the designated type, in which the high-speed data stream between the illumination and detector means and the data port is made up of data packets with data bits and type bits and with no additional header or protocol bits. The data bits contain data from the illumination and detector means and the type bits code the type of data. In the illumination and detector means and the control device, type information is stored that relates to processing functions for data types coded by means of the data bits, and, when sending the illumination and detector means and/or the control device, set the type bits for the data type in a type specification and the control device and/or the illumination and detector means defines the data types using the type bits in a type assessment and process the data coded in the data bits accordingly. According to the invention header or protocol data, as they are used in usual high-speed data systems (e.g. FireWire or USB) with serial communication and as they usually occur in a normal parallel-to-serial conversion, are dispensed with for the transmission of illumination and detector means. Therefore, a header no longer exists in the data packet as to, e.g., who is sending the data to which address in the bus they are directed, what can be done in case of error handling, etc. From the illumination and detector means to the control device, the data stream is made up exclusively of data bits and type bits, whereas the latter code information on the type of data stored in the data bits. Each module attached to the link carrying the data stream thus makes a type bit specification when delivering the data. The type bits are distinguishable from header bits of normal communications data streams by the fact that they contain no general information, but rather merely provide information on the processing of the data in the data bits which are to be subjected to in combination with type indications, which are authorized at the sending and receiving end, and the type assessment based on this at the receiving end. The high-speed data stream consequently is adjusted in a microscope-specific way and as a rule requires stored type information both on the receiving and sending end as to how the data are to be arranged or processed. This type of data communication, on the one hand, manages to eliminate any redundant information and thereby increases the effective useful rate for the data to be transmitted. On the other hand, it simplifies the data-related time and effort on the sending and receiving end, since the type specification can be designed very simply with the senders or recipients using type bits. This immediately gives the recipients the necessary information as to whether and, if need be, how they have to process data bits, or whether not at all. At the same time the senders do not have to administer and communicate address data. The invention-related conversion of the parallel, bidirectional data stream into a serial, bidirectional high-speed data stream, which is adapted to the requirements in the laser scanning microscope, further simplifies cabling in the microscope, since serial data cables need less space. In addition, a standard computer can be used for the real-time control device, and complex or costly special interfaces on the part of the real-time control device are left out. The conversion into/from the microscope-specific high-speed data stream first takes place at the data port that acts as the microscope's port. The invention-related concept for communication from the illumination and detector means to the control device is indeed particularly advantageous; however, a use in the reverse channel, which is located away from the control device, is equally possible. The utilization of high-speed data transmission with type bits has the added advantage that every data packet made up of data bits and type bits can now simultaneously be sent out or also received by multiple illumination and detector means' positions if for example the type assessment for a type of data reveals that it is relevant at different locations, e.g., by different illumination and detector means' units. With traditional address-based data communications, a simultaneous broadcasting of a data packet from and/or to different units would be impossible and instead of that multiple data packets would have to be furnished with different addresses and transmission delayed via the high-speed data stream. It is easily understandable that the useful data transmission rate achieved then would be reduced a number of times. Usually laser-scanning microscopes are broken down into individual modules, which act together in the illumination and scanning. Various illumination modules, which can be integrated into a microscope and provide radiation of various wavelengths, are an example of this. It is also a familiar practice to equip laser-scanning microscopes with different detector modules, which have, e.g., different spectral analysis capabilities. For such a modular design, it is desirable to provide a data manager to communicate with the individual modules and to connect to the individual modules according to the serial high-speed data stream, since the individual modules must be operated in coordination with each other, however, for the most part individually do not need the full data rate for communication; this data rate is only necessary in the interaction of all the modules on the part of a real-time control device. It is naturally advantageous for this design to make up the individual serial streams (which, e.g., can be designed pursuant to familiar LVDS data transmission) of data bits and types bits as well and dispensing with additional header bits between the individual modules and the data manager, since otherwise address and header information would have to be created and also transmitted by the individual modules. It will be more practical for the data manager to have the appropriate connectors for the individual modules. The data manager continues to work better with a fixed allocation scheme, by which it feeds the individual modules' data packets into the high-speed data stream. A time-consuming analysis of the individual data streams in the data manager or one requiring a processing unit is not necessary then, yet the real-time control device or the data port has to take into consideration the consolidation of the high-speed data stream from the individual data streams that is permanently set in the data manager, i.e., the individual data streams' data packets will be arranged by the data port or the real-time control device accordingly in the high-speed data stream in such a way that the allocation in the data manager is reflected in the structure of the high-speed data stream. Since a modularly designed laser scanning microscope is only seldom changed or in the case of redesign fixed connection regulations can be preset, this limitation does not constitute a hindrance. In addition, if need be, or as an alternative at the data port and/or in the real-time control device, a setting mechanism (e.g., as software or hardware device) can be provided, through which it and/or they are communicated to the individual modules that are bound to the individual data stream connectors so that the data port or the control device knows how the data packets in the high-speed data stream are composed of the individual data streams. For this reason, for a modular microscope it is advantageously provided that the illumination and detector means have multiple individual modules, which interact during the illumination and scanning, a data manager communicating with the individual modules and merging the high-speed data stream from individual serial streams of the individual modules and leading it out of the data port is connected between the data port and the individual modules of the illumination and detector means. The individual serial data streams between the data manager and individual modules are also made up of data bits and type bits and dispensing with additional header bits, the type information is stored in the individual modules and the individual modules perform the type assessment and the processing of the data coded in the data bits. Of course, this concept can also be used in direction of communication from the real-time control to the individual modules. The data manager's work is especially simple if the individual data streams are carrying data packets that are a fraction as long as the high-speed data stream's data packets. Preferably, the individual data streams' data packets are half as long as those of the high-speed data stream. Then the data manager simply composes each high-speed data stream data packet from two halves that are derived from two individual data streams. The data packet frequency of each individual data stream is then equal in size to that of the high-speed data stream, however with half the packet length. Half the frequency of the high-speed data stream is sufficient for an individual module, the data manager can make up each packet of the high-speed data stream alternatively separately from two individual data streams so that overall four individual data streams are used, which in each case have half the frequency of the high-speed data stream and half the packet length. The one high-speed data stream is then simply composed of four individual data streams. This is naturally also possible with simultaneous sending out (broadcast) of the individual data packets. In the same way, naturally, scaling is possible, i.e., two different data ports or a double data port can be provided which convert(s) the parallel data stream from the real-time data control device into two high-speed data streams. This can be practical in very complex laser-scanning microscopes. If it would be desirable to address numerous individual modules, it can be even more advantageous that multiple individual modules are connected to a single common data link and utilize this data link as a type of a data bus, whereas the type assessment in turn implicitly defines which individual module or which individual modules process or in the case of transmission send out a data packet's data that are coded in the data bits. In laser-scanning microscopes, the illumination and detector means also have actuators, which for the most part have a call back function to the control unit and which can be suited or set for operation without any impact occurring in the pixel cycle or shift being necessary, aside from elements to be controlled in a pixel-synchronous way. The pinhole shift mechanical data before the detectors are examples of such actuators. Other examples are the setting of drivers for acoustic-optical filters in illumination units, the drives for color distribution switchers or shutters, and safety screens or the like. All such components do have to have a certain setting during operation of the laser-scanning microscope, yet an activation and/or call back report occurring in the pixel cycle is unnecessary. Usually, such actuators have so far been controlled with slow working data busses, e.g., what is called a CAN bus, which implies that in traditional microscopes a (non-pixel-synchronous) slower (CAN) bus has to still be carried through the entire device along with the high-speed data communication. In the invention-related laser-scanning microscope, it is now possible to make separate settings data bus networking of the entire microscope unnecessary by embedding into the high-speed data stream with a certain type coding the settings data or callback data, which for example are added to the units according to the CAN bus protocol just mentioned, and by having the illumination and detector means extract from the high-speed data stream the settings data or the data port, the data manager or the control unit the reverse data using the type coding carried out by the respective transmitter and leading them to the actuators or processing them. The slow and not necessarily pixel-synchronous settings data, therefore, are fed into the high-speed data stream from the real-time control device or the data port and extracted on the receiving end, i.e. in the illumination and detector means. The opposite applies to reverse data. For this reason, it is provided in a preferable refinement of the microscope that the illumination and detector means have settings elements, which can be controlled when the microscope is in operation asynchronously to the pixel cycle, whereas the control device makes the suitable settings data for the settings elements, the settings elements are embedded, e.g., with a certain type coding or address into the high-speed data stream and the illumination and detector means extract the settings data and lead them to the settings elements. Alternatively or in addition this is carried out in the reverse channel. The CAN bus that was already mentioned is an efficient implementation for the forwarding of settings data to the settings elements. For this reason, it is provided for in a refinement that at least one individual module will make available a CAN bus for at least one settings element allocated to the individual module or provided for in it and will convert the settings data and/or reverse data into and/or from the CAN bus data by means of a converting element. In order to test the settings elements, which are controlled, e.g., via the CAN bus, usually full operation of the microscope is necessary, since all actuators are connected to a common CAN bus system. The invention-related design, in which the settings data are converted from and/or into the high-speed data stream from the illumination and detector means, i.e. usually from the individual modules, now allows for a design, in which the individual modules or individual components of the illumination-detector means can be tested individually. For this a diagnostic connector to the CAN bus is provided for in the individual module through which a direct CAN bus control of the settings element is possible for diagnostic and checking purposes. The diagnostic connector is therefore located between the converting element that converts the settings data from and/or into the high-speed data stream and the settings element. In that way it is possible to check the functionality of a settings element individually without having the rest of the microscope in operation. A more extensive check is possible if the converting element, which makes available, e.g., the CAN bus data, also performs a reverse conversion of the settings data into the serial data stream. Then the interaction between the control device and the individual module or its settings element can also be checked, since the control device obtains values fed in or presetting done by means of a reverse conversion at the diagnostic connector. The forward and reverse conversion in each case can be provided for, not only, individually, but also in combination. The use of individual data streams, as already mentioned, allows for a simple linking of different modules, whereas at the same time an unnecessarily high data rate is avoided on individual modules and the overall transmission rate of the high-speed data stream is distributed accordingly over the individual modules. Now the data manager can be designed in such a way that it will make an individual data stream available for each individual module. Alternatively, a option is presented whereby at least one of the individual modules has an outlet, to which it transfers the individual data stream introduced and assessed by it and through which an additional individual module is supplied. This individual data stream, therefore, is used as a data bus, whereas the length of the chain essentially is only limited by the transit time of the signals up to the last individual module and the data rate made available by the individual data stream. Such an individual data stream bus can be utilized particularly well if individual data modules are combined in it, which modules require varying data rates in both communication directions. Therefore, individual modules with a high upload rate will be more beneficially combined with individual modules that need a high download rate. In turn, naturally settings can be made at the control device or at the data port and consideration can be given to how the individual modules are linked to the individual data streams. In this way, the data manager simply can execute a segmentation and/or combination of the high-speed data stream into and/or out of the individual data stream(s). In other words, the high-speed data stream in its composition reflects the segmentation and/or combination of the individual data streams' data packets that is carried out in the data manager and how the individual modules are linked onto the individual data streams, i.e., which one of the individual data streams a certain individual module will receive. As far as the invention here is described with reference to a mechanism or a technique, this applies accordingly to the invention-related technique or mechanism, even if this matching of mechanism and technique characteristics should not be expressly mentioned. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be depicted more closely below with reference to drawings. The drawings show in: FIG. 1 is a schematic representation of a laser-scanning microscope in relation to control and data communication. FIG. 2 is a schematic representation of the laser-scanning microscope of FIG. 1 in relation to deflecting radiation in the microscope. FIG. 3 is a schematic representation similar to that of FIG. 1 with a more detailed reproduction of the configuration of the components of the microscope. FIG. 4 a is a more detailed schematic representation of a data manager in the microscope of FIGS. 1 and 3 . FIGS. 4 b , 4 c and 5 illustrate the apportionment of data packets by the data manager of FIG. 4 a. FIG. 6 is a schematic diagram of an individual module of the microscope in FIGS. 1 and 3 in relation to the control of a settings element. FIG. 7 is a schematic representation similar to FIG. 6 of a further configuration of an individual module. FIG. 8 is a schematic diagram of several individual modules, which are connected in a bus-like way to the data manager in FIG. 1 or 3 in the microscope. Furthermore, the attached Table 1 shows an example of data conversion of the microscope in FIG. 1 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. The schematic drawing in FIG. 1 shows a laser-scanning microscope system 1 that essentially is made up of a modular microscope 2 and a control device 3 . This microscope 2 represents a laser-scanning microscope known based on its principle of microscopy, with which a sample is scanned by means of raster scanning illumination as well as raster scanning detection. The microscope 2 for this reason is provided with appropriate modules 4 . 1 , 4 . 2 and 4 . 3 (they are taken together also provided with the reference number 4 ), which can be configured, for example, as a scanner module 4 . 1 , as a detector module 4 . 2 and as a laser module 4 . 3 . The modules (the number depicted in FIG. 1 is merely to be taken as an example) can be controlled by the control device 3 , whereby for the imaging a certain control situation has to exist for each pixel of an image in order that the necessary, coordinated operation of the modules is achieved. The control device 3 for this reason passes the appropriate control signals via a parallel data link 5 , which can be configured for example as a familiar PCI bus, on to the microscope 2 and receives the appropriate data from the microscope 2 . The parallel data link 5 on the microscope side is connected to a port 6 , which converts the parallel data stream into a serial data stream and passes it on via a serial high-speed data link 7 . This data link carries a serial high-speed data stream, in which the data delivered via the parallel data link 5 are carried by data packets as a serial sequence. The structure of these data packets and the mode of operation of this port 6 will be explained hereinafter. The functionality described below as well as the corresponding configuration is not limited to one direction of communication. Either of the two can only be implemented in the direction toward the modules, in the direction away from the modules or in both directions. A variation described below possibly only in one direction consequently can also be implemented in the opposite direction or in both directions. The serial data packets that are carried via the data link 7 are forwarded from a data manager 8 to three serial module data links 9 in the embodiment. The data manager 8 segments the high-speed data stream into individual data streams, which are then fed into the serial module data links 9 The control by the control device 3 has to coordinate the modules' work in virtually real time. This may be exemplified by means of the schematic drawing in FIG. 2 . It can be seen in FIG. 2 that that illumination radiation 12 provided by the laser module 4 . 3 , which excites florescence, e.g., in the sample, is directed to a sample field 10 through the scanner module 4 . 1 , whereby the sample field 10 is scanned by raster scanning of different pixels 11 . The radiation (e.g. fluorescence radiation) 13 that is caused and to be detected at an appointed position of the scanner module 4 . 1 by the illumination with an irradiation from the laser module 4 . 3 of one of the pixels 11 of the sample field 10 is in turn imaged by the scanner module 4 . 1 and then divided on a splitter 14 to the detector module 4 . 2 that verifies the radiation accordingly. An illumination beam path therefore exists between the laser module 4 . 3 upstream of the splitter 14 and the scanner module 4 . 1 , and the radiation to be detected is directed through a detection beam path from the pixel 11 , through the scanner module 4 . 1 and the splitter 14 to the detector module 4 . 2 in a detection beam path and verified at the detector. It is self-explanatory that operation and also readout of data from module 4 must be carried out in an inter-coordinated way for each of the pixels 11 . This control device 3 makes sure of this accordingly. For example, first the scanner module 4 . 1 is set to the coordinates of the pixel 11 . Then the laser module 4 . 3 is activated accordingly so that an illumination of the pixel takes place. At the same time or after a lag in time, a read out of the detected radiation is performed at the detector module 4 . 2 . The radiation intensity detected at that time is assigned to the pixel coordinates, stored accordingly and integrated into an image after completely raster scanning all pixels 11 in the sample field 10 . Of course this description as well as the representation in FIG. 2 is extremely simplified; still other controls are necessary, for instance focus adjustments, settings on a sample table, etc. But it is obvious from the description that the illumination and detector means, as they for example can be implemented by means of the individual modules 4 , have to be operated inter-coordinated in a pixel-synchronous manner that includes both the control of the modules as well as possibly the reading out of data from the modules (forward channel). What is essential here, as was mentioned, is that several modules 4 have been provided in the microscope and they, as the modules 4 . 1 - 4 . 3 , have to be operated in a pixel-synchronous manner in relation to each other, so that a certain adjustment of the modules (reverse channel) or read out of the modules is carried out with every pixel for the creation and detection of radiation intensity. The reading out or control here can change from pixel to pixel so that upon transition from one pixel to the next, as for example was already represented in FIG. 2 by means of the solid or the dotted line onto the sample field 10 , a further input of control values or read out of values is necessary at the modules by the control device 3 . The conversion of the data carried out in the microscope system 1 by means of the port 6 has various advantages. On the one hand, the control device 3 can now transmit the data over a traditional parallel data link 5 . Consequently, economical components can be utilized for the control device 3 , possibly even a store bought PC or notebook could be considered. The conversion of these data delivered in a parallel fashion into a serial high-speed data link 7 has the advantage that a simple cabling is possible in the microscope. Furthermore, a serial data stream lends itself far more easily to segmentation into the individual data streams through the serial module data links 9 or combined therefrom, as will be further described below. What is essential in the data that are carried over the serial high-speed data link 7 and then over the serial module data links 9 is that data packets are used in at least in one direction and transmit no protocol. Therefore, no header exists which receives for instance information on the sender, the receiver, address data, error handling specifications, time indications, etc. Instead, the data packets then contain exclusively data bits and type bits, whereby the data bits reproduce control data in the reverse channel, measurement data, or location report data in the forward channel and the type bits provide an indication of the type of data bits. In this way the serial high-speed data stream that runs over the data link 7 contains data packets, which combine two 16-bit packets each into a 32-bit packet, whereby the four more bits for the type coding (in bits 32 through 35 ) are transmitted in addition to the 2 times 16-bit raw data. Since the data communication from modules 4 to the control mechanism 3 contains no address information, the combination of the high-speed data stream has to take into consideration the segmentation into the serial individual data streams on the serial module data links 9 , particularly which individual modules 4 are connected to the respective serial module data links. For this reason, the data port 6 can accomplish the conversion. Alternatively, the data manager 8 can feed the initiating packets of the serial module data links 9 into or in the high-speed data stream according to a fixed plan. For instance every data packet from the link to the module 4 . 1 can become a first element of the high-speed data stream, every data packet from the link to the module 4 . 2 a second and every data packet from the link to the module 4 . 3 a third one. This similarly applies to the reverse channel. It can be provided for this variant which individual module 4 can be connected to which connector on the data manager 8 , or it will be stored in the control device 3 which module 4 is attached onto which connector of the data manager. On the other hand, it is possible that the data manager takes into consideration the structure of the high-speed data stream when it is forwarding to the individual module 4 and performs a variable conversion of the data packets. The use of the data packets of individual modules 4 over the serial module data links 9 is carried out with the configuration shown in FIG. 3 for the individual modules 4 in the following way (the explanation is carried out here, without any restriction, for the reverse channel): in the design, as it is shown in FIG. 3 , every individual module 4 is essentially subdivided into two units. The data packets of modules 4 . 1 - 4 . 3 are respectively gathered by a module operation switch 15 . 1 - 15 . 3 (when all taken together they are referenced under the reference number 15 ) and accordingly converted into control signals for the module. The module operation switches 15 , which for instance can each have an appropriate CPU, a ROM, a RAM as well as an ASIC, therefore, perform the type assessment and convert the data contained in the data packets' data bits, depending on the specification in the type bits, possibly into the corresponding control processes. The control will be carried out then over an operation link 16 . 1 , 16 . 2 , 16 . 3 (taken together under the reference number 16 ). Each operation link 16 leads to the corresponding module element 17 . 1 , 17 . 2 , 17 . 3 , (taken together accessed as module elements 17 ), which carry out the appropriate function in the laser-scanning microscope 2 . In the embodiment in FIG. 3 the module element 17 . 1 includes two galvanometer mirrors positioned at right angles to each other, the module element 17 . 2 a PMT and the module element 17 . 3 an illumination laser. In the forward channel the type assessment is replaced by the type big specification. The corresponding module operation switches 15 provide the respective module elements 17 via the operation links 16 with the appropriate supply voltages, control signals or read out the appropriate location report and measurement value signals. Every module operation switch 15 for this reason with the type assessment in the reverse channel checks whether the type bits indicate that the following data packets' data bits have to be converted from the module operation switch 15 into a corresponding control. At the same time, depending on the module in the reverse channel, the module operation switch 15 can create a corresponding data packet, e.g. with measurement values, by combining a corresponding coding (type bits) with appropriate values (data bits) in a data packet and leading it back over the serial module data link 9 to the data manager 8 and from there over the serial high-speed data link 7 and the port 6 on the parallel data link to the control device 3 . This functionality will now be described for the reverse and the forward channel for the example of the scanner module. For the complete raster scanning of a pixel 11 the control device 3 specifies via the parallel data line 5 that the scanner mirror should assume a certain position. This position specification is converted from the port 6 data packet of the serial high-speed data stream via the serial high-speed data link 7 . Thus at least one data packet runs over the serial high-speed data link 7 , which packet contains type bits (e.g. four type bits) that indicate that the following data bits that reproduce the position (coordinates) to be assumed by the galvanometer mirror. Upon segmentation of the high-speed data stream in the data manager 9 this data packet runs in the reverse channel over the serial module data link 9 to the module operation switch 15 . 1 . The module operation position 15 . 1 initiates a type assessment of all data packets, which are supplied to it over its serial module data link 9 . In this assessment it recognizes in the type bits of the said data packet that new coordinates are specified for the galvanometer mirror. The module operation switch 15 . 1 then provides appropriate voltage signals over the operation data link 16 . 1 to the module element 17 . 1 , i.e. the galvanometer mirror. The galvanometer mirrors thereupon assume the desired position. Since in the embodiment the galvanometer mirrors have a position report, the module operation switch 15 . 1 recognizes through the operation link 16 . 1 that the galvanometer mirror is in the desired position and thereupon creates a data packet for the forward channel, the data bits of which code the position the galvanometer mirror achieved and provides these data bits with the appropriate type bits, which are provided for in system 1 for this type of information and provides these data bits with the appropriate type bits, which are provided for in system 1 for this type of information. This report goes over the serial module data link 9 , the data manager 8 , the high-speed data link 7 , the port 6 as well as the parallel data link 5 and makes its way to the control device 3 , which thereby knows that the galvanometer mirrors, i.e. the scanner module 4 . 1 are adjusted to the coordinates of the desired pixel 11 . In the next step the control device 3 then effects delivery of illumination laser radiation, in turn by carrying out a corresponding reverse channel control via the parallel data link 5 so that in the end the module operation switch 15 . 3 contains a data packet, whose data bits code the details of the illumination radiation to be delivered, for instance the frequency, pulse start and pulse duration of a laser radiation pulse, which is recognized by the module operation switch 15 . 3 in the type bits of the data packet. A status report on delivery of the desired laser pulse is carried out possibly similarly as with the scanner module described in the forward channel. In a similar manner the control device 3 causes the detector module to operate, during which in the forward channel the PMT in the module element 17 . 2 accordingly is also controlled via the operation link 16 . 2 and measurement values are delivered back and in the reverse channel corresponding data packets arrive at the module operation switch 15 . 2 . In the embodiment in FIGS. 1 and 3 , the data manager 8 , as mentioned, performs a fixed combination and/or segmentation of the data stream carried over the serial high-speed data link 7 . For instance, as is shown in FIG. 4 a , the data manager accomplishes a feed from two serial module data links 9 A and 9 B, according to the plan as it is shown in the FIGS. 4 b and 4 c . Naturally, a combination or segmentation can also be carried out from and into more than two module data links. In FIG. 4 a for this reason two additional module data links 9 C and 9 D are shown. FIG. 4 b shows a high-speed data packet (hereinafter HS data packet for short) of the high-speed data stream that is designed as a 32-bit word. The data manager 8 segments this 32-bit word into two 16-bit words, which thereby constitute two data packets 20 and 21 . These data packets are transmitted for instance with signals in accordance with the LVDS standard, as it is described, e.g., in the LVDS Owner's Manual, 3 rd edition, 2004, National Semiconductor, USA. The first data packet 20 is allocated to the first serial module data links 9 A, the second data packet 21 to the second module data link 9 B. Either by means of the control device 3 or by means of the port 6 it is seen to that the configuration of the 32-bit HS data packet 18 takes into consideration this permanently set segmentation in the data manager 8 . An equally possible structure, in which type bits are only used in the forward channel, is shown in the enclosed Table 1. Each data packet 20 , 21 has type bits T and data bits D. The 32-bit HS data packet 18 contains, e.g., starting from the bit no. 0 as well as from the bit no. 16 the type bits T, to which data bits D connect, which run up to bit no. 15 or bit no. 31 respectively. In the variant shown in FIG. 4 b four respective type bits T are provided, which are drawn in the figure hatched. By means of the segmentation into two data packets 20 and 21 , then in the data manager 8 each of the 16-bit words at the beginning has (e.g. four) type bits T, to which the (e.g. 12) data bits D connect. FIG. 5 shows an exemplary case in which the data manager 8 also includes the module data links 9 C and 9 D. Here two subsequent 32-bit long HS data packets 18 and 19 of the high-speed data stream are divided into a total of four 16-bit data packets 20 , 21 , 22 and 23 , which are allocated to the module data links 9 A, 9 B, 9 C and 9 D. That principle corresponds to the one described using FIGS. 4 b and 4 c , with the difference being that two subsequent HS data packets 18 and 19 and brought in. Therefore, the first half of a first HS data packet 18 is allocated to the serial module data link 9 A, the second half of the first HS data packet 18 is allocated to the serial module data link 9 B, the first half of the second HS data packet 19 to the module data link 9 C and the second half of the second HS data packet 19 to the serial module data link 9 D. FIG. 6 schematically shows in detail an exemplary configuration of an individual module, here of a detector. The module operation switch 15 . 2 of the detector as well as the module element 17 . 2 is depicted. As can be seen, the module element 17 . 2 has a schematically drawn in PMT 24 as well as pinhole shift mechanical data 25 , which a pinhole upstream to the PMT 24 shifts in relation to situation and size. This pinhole is of essential significance for the confocal illustration of the laser-scanning microscope 2 . The position and size of the pinhole 25 have to have certain values during the operation of the microscope 2 . A shift during the complete raster scanning of the sample field 2 , i.e., a pixel-specific adjustment is on the other hand as a rule not necessary. Accordingly, the module operation switch 15 . 2 is also equipped with two sub-modules, a PMT operation module 29 as well as a CAN bus module 30 . The PMT operation module performs the control and reading out of the PMT 24 that was already mentioned and for this reason is linked to the PMT 24 via an HS link 31 . The CAN bus module 30 is connected via a CAN bus 32 to the pinhole shift mechanical data 25 and directs this with CAN data pursuant the familiar CAN bus. The module operation switch 15 . 2 therefore has an operation module, which has to work in a pixel-synchronous manner and as a rule in the high frequency range, that is to say the PMT operation module 29 , as well as a slowly working bus module, which controls the pinhole adjustment with non-pixel-synchronous settings data; in the embodiment this is carried out via a CAN bus. Both the pixel-asynchronous data as well as the pixel-synchronous high frequency data are communicated with the module operation switch 15 . 2 via the serial module data link 9 . Not only are pixel-synchronous (high frequency) data included in the data packets, which flow above the data stream of the serial module data link 9 and which also are carried in the serial high-speed data stream of the serial high-speed data link 7 , but rather also pixel-asynchronous settings data are embedded; the latter are used at least in one direction with a certain type recognition also a traditional address indication. In the opposite direction instead of type recognition the corresponding segmentation or combination of these different data types in the individual module is produced by a splitter 28 , which on the one hand is linked to the serial module data link 9 and on the other hand forwards which the high frequency or settings data forward to the PMT operation module 29 or the CAN bus module 30 . For this it performs a type evaluation or assessment. Naturally, this configuration described using the detector module is in principle possible in an embodiment of the invention for additional or all detection and illumination means. This embodiment has the advantage that the control device 3 can control not only those parts of the illumination and detector means in real time, which need pixel-synchronous control or reading out, but rather also part of the microscope 2 , which can only be in a certain position when in operation, yet do not have to be adjusted in the pixel cycle. At the same time, the control of these settings elements with traditional (slow) bus systems, as result from the CAN bus, without a separate cabling of the microscope 2 having to be provided for according to this bus. Thus such a bus interface can itself be dispensed with in the control device 3 and also in the microscope 2 . FIG. 7 shows a further configuration of an individual module controlled via a serial module data link 9 pursuant to FIG. 6 . The configuration essentially corresponds to that in FIG. 6 , so that elements described there do not have to be explained once again. The refinement consists in the fact that in the module operation switch 15 . 2 on the CAN bus 32 a CAN bus branch connection 33 is provided, which empties into a externally accessible CAN bus connector 34 . This connector 34 can either be provided directly on the module operation switch 15 . 2 , or also on a suitable other place on the microscope 2 , particularly an arrangement is possible on a diagnostic adapter board. The proper functioning of the pinhole adjustment mechanical data will now be checked in this simple way by feeding in the appropriate CAN bus signals from a diagnostics device on the connector 34 . The mode of operation of the corresponding module can also be checked by reading along of the signals coming in at the CAN bus connector 34 , which the CAN bus module 30 provides via the CAN bus 32 for the pinhole adjustment mechanical data 25 . Finally, it can also be provided for in a repeated refinement that the CAN bus module 30 on the connector 34 reconverts CAN data fed in and feeds in via the splitter 28 into the module data stream of the serial module data link 9 . Thus a reverse diagnostics is also possible. In the embodiments described, the data manager 8 carries out a combination or segmentation of the high-speed data stream of the high-speed data link 7 out from and into individual data streams, which are linked to serial individual module links 9 , for instance the links 9 A, 9 B and possible 9 C and 9 D. At the same time, case constellations were explained, in which each individual module has an independent serial module data link. This, however, is not absolutely necessary. The data manager 8 for instance can also use the module data link 9 as a bus. For this reason on the corresponding individual modules, which are shown by way of example as individual modules 35 and 40 in FIG. 8 , on the entrance side a branching node 37 is provided that directs all data packets supplied through the module data link 9 to a forwarding branch 38 or funnels incoming data packets to the serial module data link 9 . The forwarding branch 38 ends in a bus connector 39 to which an additional individual module 40 , which essentially corresponds to the individual module 35 , is connected by means of a bus link 40 . Consequently, several individual modes are divided into a serial module data link in the manner of a bus, whereby in turn the type specification or type assessment, which is performed within the module 35 or 40 by an assessment unit 36 , defines which data the data bits contain from which it follows (implicitly) whether the respective module processes a data packet. Such an assessment unit 36 is in principle provided for in each individual module either as an independent element or its function is performed by another component. Modifications and variations of the above-described embodiments of the present invention are possible, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described. TABLE 1

Specimen laser-scanning microscope with raster scanning illumination and detector modules, which illuminates and detects a specimen by raster scanning. A real-time control device (device) performs synchronous reading-out with the raster scanning pixel cycle. A data port serially communicates with the device using a bidirectional high-speed data stream and with the resources via a serial, bidirectional high-speed data stream with a data conversion to/from parallel to serial. The high-speed data stream is made up of data packets with data bits and type bits and no additional header or protocol bits. The data bits contain data from/on the resources and the type bits code the type of data. Type information is stored in the resources as well as the device. The type information defines processing functions for data types coded by the type bits, and the resources and/or the device determine the data type using type bits and process data coded in the data bits.

CROSS REFERENCE TO RELATED APPLICATION This application is a divisional of U.S. patent application Ser. No. 09/736,068, filed Dec. 13, 2000 now U.S. Pat. No. 6,516,291 which is hereby incorporated by reference herein in its entirety. BACKGROUND OF THE INVENTION The present invention relates to apparatus and methods for providing an output signal proportional to the root-mean-square (RMS) value of an input signal. More particularly, the present invention relates to apparatus and methods for detecting an output fault condition and for recovering from such a condition so that an output signal is provided. The output signal may be a direct current (DC) signal proportional to the RMS value of an input signal (commonly called RMS-to-DC conversion). The RMS value of a waveform is a measure of the heating potential of that waveform. RMS measurements allow the magnitudes of all types of voltage (or current) waveforms to be compared to one another. Thus, for example, applying an alternating current (AC) waveform having a value of 1 volt RMS gain stage 36 . Gain stage 36 has an output V OUT , and provides a broadband gain A. To simplify the description of pulse modulator 32 and demodulator 34 , the following discussion first assumes that A=B=1 (although in practice it is common for A=B>1). As described below, this assumption only affects a scale factor in the resulting analysis. Pulse modulator 32 may be any commonly known pulse modulator, such as a pulse code modulator, pulse width modulator, or other similar modulator. As shown in FIG. 1, pulse modulator 32 is implemented as a single-bit oversampling ΔΣ pulse code modulator, and includes integrator 40 , comparator 41 , switch 42 , non-inverting buffer 44 , and inverting buffer 46 . As described in more detail below, switch 42 and buffers 44 and 46 form a single-bit multiplying digital-to-analog converter (MDAC) 47 . Integrator 40 has a first input coupled to input V IN , a second input coupled to the pole of switch 42 , and an output coupled to an input of comparator 41 . Comparator 41 has a clock input coupled to clock signal CLK, and an output V 1 coupled to control terminals of switches 42 and 52 . Clock CLK is a fixed period clock that has a frequency that is much higher than the frequency of input V IN (e.g., 100 times greater). Comparator 41 compares the signal at the output of integrator 40 to a reference level (e.g., GROUND), and latches the comparison result as output signal V 1 on an edge of clock CLK. Non-inverting buffer 44 provides unity gain (i.e., +1.0) and has an input coupled to the output of gain stage 38 , and an output coupled to the first terminal of switch 42 . Inverting buffer 46 provides across a resistor produces the same amount of heat as applying 1 volt DC voltage across the resistor. Mathematically, the RMS value of a signal V is defined as: V rms = V 2 _ ( 1 ) which involves squaring the signal V, computing the average value (represented by the overbar in equation (1)), and then determining the square root of the result. Various previously known conversion techniques have been used to measure RMS values. One previously known conversion system uses oversampling analog-to-digital converters to generate precise digital representations of an applied signal. The digital representations are demodulated and filtered to produce a DC output signal that has the same heat potential as the applied signal. This type of system is attractive to circuit designers because it produces highly accurate results and can be efficiently implemented on an integrated circuit. FIG. 1 is a generalized schematic representation of a portion of an RMS-to-DC converter circuit. As shown in FIG. 1, RMS-to-DC converter circuit 30 includes pulse modulator 32 , demodulator 34 , gain stage 36 , gain stage 38 , and lowpass filter 54 . Pulse modulator 32 has a first input coupled to V IN , a second input coupled to the output of gain stage 38 and an output V 1 . Demodulator 34 has an input coupled to V IN , a control input coupled to V 1 , and an output V 2 . Gain stage 38 has an input coupled to V OUT , and provides a broadband gain B. Lowpass filter 54 has an input coupled to V 2 and an output V 3 coupled to the input of inverting gain (i.e., −1.0) and has an input coupled to the output of gain stage 38 , and an output coupled to the second terminal of switch 42 . V 1 is a signal having a binary output level (e.g., −1 or +1). If V 1 =+1, the pole of switch 42 is coupled to the output of non-inverting buffer 44 . That is, (assuming gain B=1)+V OUT is coupled to the second input of integrator 40 . Alternatively, if V 1 =−1, the pole of switch 42 is coupled to the output of inverting buffer 46 . That is, (assuming gain B=1)−V OUT is coupled to the second input of integrator 40 . This switching configuration provides negative feedback in pulse modulator 32 . The first and second inputs of integrator 40 therefore can have values equal to: − V OUT ≦V IN ≦+V OUT   (2) and V IN thus has a bipolar input signal range. From equation (2), if V 1 has a duty ratio D between 0-100%, D can be expressed as: D = 1 2 × ( V IN V OUT + 1 ) , 0 ≤ D ≤ 1 ( 3 ) That is, if V IN −V OUT , D=0, and if V IN =+V OUT , D=1. Demodulator 34 includes non-inverting buffer 48 , inverting buffer 50 and switch 52 , which form a single-bit MDAC. Non-inverting buffer 48 has an input coupled to V IN , and an output coupled to a first terminal of switch 52 . Inverting buffer 50 has an input coupled to V IN , and an output coupled to a second terminal of switch 52 . Switch 52 has a control terminal coupled to V 1 and a pole coupled to the input of lowpass filter 54 . If V 1 =+1, the pole of switch 52 is coupled to the output of non-inverting buffer 48 . That is, +V IN is coupled to the input of lowpass filter 54 . Alternatively, if V 1 =−1, the pole of switch 52 is coupled to the output of inverting buffer 50 . That is, −V IN is coupled to the input of lowpass filter 54 . Demodulator 34 provides an output signal V 2 at the pole of switch 52 that may be expressed as: V 2 =    + V IN × D - ( - V IN ) × ( D - 1 )    ( 4  a ) =    V IN × ( 2 × D - 1 )    ( 4  b ) Substituting equation (3) into equation (4b), V 2 is given by: V 2 = V IN 2 V OUT ( 5 ) Lowpass filter 54 may be a continuous-time or a discrete-time filter, and provides an output V 3 equal to the time average of input V 2 . Accordingly, V 3 equals: V 3 = V IN 2 _ V OUT ( 6 ) Gain stage 36 provides an output V OUT equal to (assuming gain A=1) V 3 : V OUT =    V IN 2 _ V OUT    ( 7  a ) =    V IN 2 _ = V RMS    ( 7  b ) Thus, circuit 30 has a bipolar input range and provides an output V OUT equal to the RMS value of input V IN . Demodulator 34 and stage 47 each are single-bit MDACs and comparator 41 is a single-bit analog-to-digital converter (ADC) that provides a single-bit output V 1 . The difference between the output of integrator 40 and MDAC 47 equals the quantization error e[i] of pulse modulator 32 . Because the output of comparator 41 controls the polarity of the feedback signal from V OUT to the input integrator 40 , converter 30 will remain stable for only one polarity of V OUT . If V OUT has a polarity opposite of that assumed for the connection of switch 42 (e.g., during power up, a brown out, or a load fault), modulator 32 will become unstable, and the output of integrator 40 will quickly approach a rail voltage. With a DC input, this may not be problematic, because the state of V 1 might be such that V IN propagates through MDAC 34 and results in the V 2 polarity desired for V OUT . In this case, once any external influences on V OUT are removed, V 2 (and therefore V OUT ), will return to the proper polarity once it propagates through low pass filter 54 . This sequence, however, has a probability of occurring only about 50% of the time, meaning that converter 30 is unlikely to recover in almost half of the possible DC operating cases. Moreover, RMS-to-DC converters are most often used with AC signals, and in those instances output recovery is even less likely to occur. Thus, in view of the foregoing, it would be desirable to provide methods and apparatus for performing RMS-to-DC conversions that have improved recovery characteristics. SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provide methods and apparatus for performing RMS-to-DC conversions that have fault detection and recovery capabilities. In accordance with this and other objects of the present invention, circuitry and methods that supply the root-mean-square (RMS) value of an input signal and that detect and independently recover from output fault conditions are provided. The circuit of the present invention includes reconfigurable circuitry that changes from normal operating mode to fault recovery mode when an output fault is detected. During fault recovery mode, the circuit of the present invention generates a modified output signal that allows independent recovery from an output fault condition. Once recovery is complete, the circuit returns to the RMS mode of operation. BRIEF DESCRIPTION OF THE DRAWINGS The above-mentioned objects and features of the present invention can be more clearly understood from the following detailed description considered in conjunction with the following drawings, in which the same reference numerals denote the same structural elements throughout, and in which: FIG. 1 is a schematic diagram of a previously known RMS-to-DC converter circuit; FIG. 2A is a schematic diagram of an RMS-to-DC converter circuit of the present invention; FIG. 2B is another schematic diagram of an RMS-to-DC converter circuit of the present invention; FIG. 3A is another schematic diagram of an RMS-to-DC converter circuit of the present invention; FIG. 3B is another schematic diagram of an RMS-to-DC converter circuit of the present invention; FIG. 4A is another schematic diagram of an RMS-to-DC converter circuit of the present invention; FIG. 4B is another schematic diagram of an RMS-to-DC converter circuit of the present invention; FIG. 5 is a schematic diagram of the reconfigurable ΔΣ modulator of FIGS. 2 - 4 . DETAILED DESCRIPTION OF THE INVENTION FIG. 2A illustrates an embodiment of RMS-to-DC converter constructed in accordance with the principles of the present invention. Circuit 130 includes pulse modulator 132 , demodulator 134 , gain stages 36 and 38 , lowpass filter 54 , and optional delay-matching stage 82 . To simplify the description of modulator 132 and demodulator 134 , the following discussion assumes that A=B=1 (although in practice it is common for A=B>1). This assumption only affects a scale factor in the resulting analysis. Pulse modulator 132 includes cascaded AZ pulse code modulators. In particular, pulse modulator 132 includes reconfigurable ΔΣ stage 72 , ΔΣ stage 76 , monitor circuit 73 , delay stage 78 , and subtractor 80 . As described in more detail below, ΔΣ stage 76 , delay stage 78 , and subtractor 80 provide an estimate of the spectrally-shaped quantization error of reconfigurable ΔΣ stage 72 . Reconfigurable ΔΣ stage 72 has a first input coupled to V IN , a second input coupled to the output of gain stage 38 (through switch 75 ), a first output coupled to the input of monitor circuit 73 , and a second output V 4 coupled to a first input of ΔΣ stage 76 . ΔΣ stage 76 has a second input coupled to the output of gain stage 38 , and an output V 5 coupled to a non-inverting input of subtractor 80 and to an input of delay stage 78 . Subtractor 80 has an inverting input coupled to an output of delay stage 78 , and an output V 1b coupled to a control terminal of switch 96 . Monitor circuit 73 may include a delay stage (not shown) to match the delay through ΔΣ stage 76 , and has an output V 1a coupled to a control terminal of switch 88 . ΔΣ stages 72 and 76 may be, for example, single-bit modulators that can be of any order. Preferably, reconfigurable ΔΣ stage 72 is a first-order stage. Reconfigurable first-order ΔΣ stage 72 and monitor circuit 73 provide output V 1a equal to (assuming gain B=1): V 1  a  [ i + 1 ] = ( V IN  [ i - 1 ] ) V OUT + ( e  [ i ] - e  [ i - 1 ] ) V OUT ( 8 ) where index i denotes the sample index and e[i] is the quantization error of reconfigurable ΔΣ stage 72 . V 1a thus equals the desired ratio of the input divided by V OUT , plus the spectrally-shaped quantization error of reconfigurable ΔΣ stage 72 divided by V OUT . ΔΣ stage 76 , delay stage 78 and subtractor 80 provide an output V 1b equal to an estimate of the spectrally-shaped quantization error of reconfigurable ΔΣ stage 72 divided by V OUT . In particular, V 4 is the quantization error e[i] of reconfigurable ΔΣ stage 72 , which is a function of the input signal V IN , the state of the integrator, and the local feedback within the MDAC of reconfigurable ΔΣ stage 72 . ΔΣ stage 76 provides an output V 5 equal to (assuming gain B=1): V 5  [ i + 1 ] = ( 1 V OUT ) × [ e  [ i ] + ( e ′  [ i + 1 ] - e ′  [ i ] ) ] ( 9 ) where e′[i] is the quantization error of ΔΣ stage 76 . Delay stage 78 and subtractor 80 form a digital differentiator that provide an output V 1b equal to (assuming gain B=1): V 1  b  [ i + 1 ] = ( 1 V OUT ) × [ e 1 + e 2 ] ( 10 ) where e 1 =e[i]−e[i −1]  (11a) e 2 =e′[i +1]−2e′[i]+ e′[i −1]  (11b) Delay stage 82 matches the combined delay through pulse code modulator 132 . Demodulator 134 provides an output proportional to input V IN times the ratio of V IN to V OUT . In particular, demodulator 134 includes non-inverting buffer 84 , inverting buffer 86 , switch 88 , subtractor 90 , non-inverting buffer 92 , inverting buffer 94 , three-position switch 96 and multiply-by-two stage 97 . Non-inverting buffer 84 provides unity gain (i.e., +1.0) and has an input coupled through delay stage 82 to input V IN , and an output coupled to the first terminal of switch 88 . Inverting buffer 86 provides inverting gain (i.e., −1.0) and has an input coupled through delay stage 82 to input V IN , and an output coupled to the second terminal of switch 88 . Non-inverting buffer 84 , inverting buffer 86 and switch 88 form a single-bit MDAC. V 1a is a binary signal having a binary output level (e.g., −1 or +1). If V 1a =+1, the pole of switch 88 is coupled to the output of non-inverting buffer 84 . That is, +V IN is coupled to first input V 6 of subtractor 90 . Alternatively, if V 1a =−1, the pole of switch 88 is coupled to the output of inverting buffer 86 . That is, V IN is coupled to first input V 6 of subtractor 90 . V 6 equals (assuming gain B=1): V 6  [ i + 1 ] =    V IN  [ i - 1 ] V OUT × V 1  a  [ i + 1 ]    ( 12  a ) =    V IN  [ i - 1 ] V OUT × ( V IN  [ i - 1 ] + e 1 )    ( 12  b ) Non-inverting buffer 92 provides unity gain (i.e., +1.0) and has an input coupled through delay stage 82 to input V IN , and an output coupled to the first terminal of three-position switch 96 . Inverting buffer 86 provides inverting gain (i.e., −1.0) and has an input coupled through delay stage 82 to input V IN , and an output coupled to the third terminal of three-position switch 96 . The second terminal of three-position switch 96 is coupled to GROUND. Non-inverting buffer 92 , inverting buffer 94 and three-position switch 96 form a 1.5-bit MDAC. Multiply-by-two stage 97 provides a gain of +2.0. V 1b is a tri-level signal having output values of −2, 0 or +2. If V 1b =+2, the pole of three-position switch 96 is coupled to the output of non-inverting buffer 92 . That is, +2V IN is coupled to second input V 7 of subtractor 90 . If V 1b =0, the pole of switch 96 is coupled to GROUND, and therefore 0 is coupled to second input V 7 of subtractor 90 . If, however, V 1b =−2, the pole of switch 96 is coupled to the output of inverting buffer 94 . That is, −2V IN is coupled to second input V 7 of subtractor 90 . V 7 equals (assuming gain B=1): V 7  [ i + 1 ] = V IN  [ i - 1 ] V OUT × ( e 1 + e 2 ) ( 13 ) Subtractor 90 provides an output V 8 that equals the difference between V 6 and V 7 : V 8  [ i + 1 ] =    V 6  [ i + 1 ] - V 7  [ i + 1 ]    ( 14  a ) =    V IN  [ i - 1 ] 2 V OUT - V IN  [ i - 1 ] 2 V OUT × e 2    ( 14  b ) Thus, V 8 is proportional to V IN squared divided by V OUT , substantially without the quantization noise of reconfigurable ΔΣ stage 72 . The quantization noise e 2 of ΔΣ stage 76 remains, but the low frequency portion of that noise is further reduced by the spectral shaping provided by delay 78 and subtractor 80 . Further, because e 2 is uncorrelated with V IN , the DC average of the product of e 2 and V IN equals zero. As a result, output V 9 of lowpass filter 54 approximately equals: V 9 ≈ V IN 2 _ ( 15 ) Output V OUT of gain stage 36 approximately equals (assuming gain A=1): V OUT ≈ V IN 2 _ ( 16 ) The circuit of FIG. 2A may be implemented using single-ended or differential circuitry. During operation, output signals from reconfigurable ΔΣ stage 72 may pass through monitor circuit 73 to the pole of switch 88 . As mentioned above, when V OUT changes polarity, ΔΣ stages 72 and 76 become unstable, producing a string of output bits with the same logic level. Monitor circuit 73 , which may include counter circuits and/or latch circuitry (not shown), detects this string and interprets it as a “fault condition.” In response to the detected fault condition, monitor circuit 73 generates a control signal that causes circuit 130 to switch from RMS-to-DC conversion mode to fault recovery mode. The number of consecutive same logic level bits that constitute a fault condition may be varied if desired. For example, with certain modulator topologies, the number of bits may be set to be relatively long (e.g., about 50) to ensure circuit 130 does not enter recovery mode inadvertently. In other applications, however, the number of bits may be somewhat less (e.g., about 15) to reduce recovery time. In fault recovery mode, switch 75 is opened, breaking the feedback path from output V OUT to ΔΣ stage 72 . In addition, some components within ΔΣ stage 72 are reconfigured so that ΔΣ stage 72 functions as a comparator circuit rather than as a modulator circuit (shown as comparator circuit 77 in FIG. 2 B). With this arrangement, shown in FIG. 2B, circuit 130 operates as a mean-absolute-detect circuit instead of an RMS-to-DC converter. Circuit 130 thus determines the average of the absolute value of input signal V IN . Although this measurement is less meaningful than the RMS value of the input signal, it ensures circuit 130 will produce an output signal V OUT that has the proper polarity. Once V OUT returns to the correct polarity, the bit stream produced by ΔΣ stage 76 toggles, indicating that the fault condition has cleared. Monitor circuit 73 detects this change of logic level and returns circuit 130 to RMS-to-DC conversion mode (i.e., closes switch 75 and reconfigures comparator 77 to operate as ΔΣ stage 72 ). In this way, circuit 130 may detect and recover from fault conditions irrespective of the type and amplitude of input signal V IN . As shown in FIG. 2B, to operate as a mean-absolute-detect circuit, the feedback from V OUT to comparator 77 is disconnected. The output signal produced by comparator 77 is a bit stream that represents the polarity of input signal V IN . Comparator 77 may be configured as a polarity detector using any suitable arrangement known in the art (e.g., by connecting a threshold terminal to ground and a sensing terminal (both not shown) to input signal V IN ). When the output of comparator 77 is provided to demodulator 134 (i.e., the pole of switch 88 ), the input signal V IN is multiplied by its own polarity, thus performing an absolute value operation. The resulting signal is then fed through lowpass filter 54 which provides an output signal V OUT of the desired polarity (assuming any external stimuli has been removed from the output node). As long as output signal V OUT is the incorrect polarity, ΔΣ stage 76 will be unstable, and its output will remain at either a logic low or a logic high (depending on its state when the output fault occurred). When this occurs, subtractor 80 has a substantially zero output and will not affect the value of V OUT . When circuit 130 is operating in mean-absolute-detect mode, error signal V 4 produced by comparator 77 is the input signal V IN (or a scaled version thereof). Thus, the output of ΔΣ stage 76 can be monitored (by monitor circuit 73 ) to determine when recovery from an output fault has occurred. For example, when the bit stream produced by ΔΣ stage 76 toggles from one logic state to another, circuit 130 has recovered from the fault condition and may be reconfigured back to the RMS-to-DC converter shown in FIG. 2 A. The overall gain of circuit 130 during fault recovery (i.e., mean-absolute-detect mode) does not need to be similar to that of the RMS-to-DC mode (i.e., normal operation). However, increased gain during fault recovery does tend to reduce recovery time. Moreover, it will be understood that with certain input waveforms and filter time constants, circuit 130 may go into fault recovery, back to normal operation, and return to fault recovery several times in succession. As long as the output is free of external influences however, circuit 130 will recover. The successive fault mode periods will become shorter in duration until circuit 130 has fully recovered. FIG. 3A shows another illustrative embodiment of RMS-to-DC converter constructed in accordance with the present invention. Converter 230 includes single-sample delay stages 82 and 104 , modulator 232 and demodulator 234 . Modulator 232 includes single-bit reconfigurable ΔΣ stage 72 , ΔΣ stage 76 , and monitor circuit 73 , and demodulator 234 includes single-bit MDAC stages 98 , 100 and 102 , and adder/subtractor 106 . MDACS 98 , 100 , and 102 may be implemented as in demodulator 34 of FIG. 1 . Alternatively, some of MDACS 98 , 100 and 102 may be implemented as a single time-multiplexed MDAC. Reconfigurable ΔΣ stage 72 provides a quantized output V 1c equal to (assuming gain B=1): V 1  c  [ i ] = V IN  [ i - 1 ] + e  [ i ] - e  [ i - 1 ] V OUT ( 17 ) In addition, V 4 equals the quantization error e[i] of reconfigurable ΔΣ stage 72 . ΔΣ stage 76 provides a quantized output V 1d equal to (assuming gain B=1): V 1  d  [ i ] = e  [ i - 1 ] + e ′  [ i ] - e ′  [ i - 1 ] V OUT ( 18 ) Single-bit DACs 98 , 100 and 102 provide outputs V 10 , V 11 and V 12 , respectively, equal to (assuming gain B=1): V 10 [i]=V IN [i −1 ]×V 1c [i]   (19)   V 11 [i]=V IN [i −1 ]×V 1d [i]   (20) V 12 [i]=V IN [i −2 ]×V 1d [i]   (21) Adder/subtractor 106 provides an output V 13 equal to: V 13 [i]=V 10 [i]+V 11 [i]−V 12 [i]   (22) which equals (assuming gain B=1): V 13  [ i ] = V IN  [ i - 1 ] V OUT × ( V IN  [ i - 1 ] + e  [ i ] + e ′  [ i ] - e ′  [ i - 1 ] ) - V IN  [ i - 2 ] V OUT × ( e  [ i - 1 ] + e ′  [ i ] - e ′  [ i - 1 ] ) ( 23 ) Note that: V 13  [ i + 1 ] = V IN  [ i ] V OUT × ( V IN  [ i ] + e  [ i + 1 ] + e ′  [ i + 1 ] - e ′  [ i ] ) - V IN  [ i - 1 ] V OUT × ( e  [ i ] + e ′  [ i + 1 ] - e ′  [ i ] ) ( 24 ) If the time constant of lowpass filter 54 is much greater than the sample period of V 13 [i] (e.g., 10,000 times), lowpass filter 54 provides output V 14 that is the average of sequence V 13 . V 13 as a function of V IN [i−1] approximately equals: V 13 ∣ V IN  [ i - 1 ] ≈ V IN  [ i - 1 ] V OUT × ( V IN  [ i - 1 ] + e  [ i ] + e ′  [ i ] - e ′  [ i - 1 ] ) - V IN  [ i - 1 ] V OUT × ( e  [ i ] + e ′  [ i + 1 ] - e ′  [ i ] ) ( 25 ) which may be written as: V 13 ∣ V IN  [ i - 1 ] = ( V IN  [ i - 1 ] V OUT ) 2 - V IN  [ i - 1 ] × ( e ′  [ i + 1 ] - 2  e ′  [ i ] + e ′  [ i - 1 ] ) V OUT ( 26 ) The first term on the right side of equation (26) is the desired output, and the second term equals the second-order spectrally-shaped quantization noise of ΔΣ stage 76 , which is substantially reduced by lowpass filter 54 . Further, because e′ is uncorrelated with V IN , the DC average of the product of e′ and V IN equals zero. As a result, V 14 approximately equals: V 14 = V 13 _ ≈ V IN 2 _ V OUT ( 27 ) Output V OUT of gain stage 36 approximately equals (assuming gain A=1): V OUT ≈ V IN 2 _ ( 28 ) The circuit of FIG. 3A may be implemented using single-ended or differential circuitry. During operation, output signals from reconfigurable ΔΣ stage 72 may pass through monitor circuit 73 to MDAC 98 . As mentioned above, when V OUT changes polarity, ΔΣ stages 72 and 76 become unstable, producing a string of output signals with a constant logic level. Monitor circuit 73 detects this output string, which it interprets as a “fault condition” and generates a control signal that causes circuit 230 to switch from RMS-to-DC conversion mode to fault recovery mode. In fault recovery mode, switch 75 is opened, breaking the feedback path from output V OUT to ΔΣ stage 72 . Additionally, some components within ΔΣ stage 72 are reconfigured so that ΔΣ stage 72 functions as a comparator circuit rather than as a modulator circuit (shown as comparator circuit 77 in FIG. 3 B). In this arrangement, shown in FIG. 3B, circuit 230 operates as a mean-absolute-detect circuit instead of an RMS-to-DC converter. Circuit 230 thus determines the average of the absolute value of the input signal. Although this measurement is less meaningful than the RMS value of the input signal, it ensures circuit 230 will produce an output signal V OUT that has the proper polarity. Once V OUT returns to the proper polarity, the bit stream produced by comparator 77 toggles, indicating that the fault condition has cleared. Monitor circuit 73 detects this change of logic level and returns circuit 230 back to RMS-to-DC conversion mode (i.e., closes switch 75 and reconfigures comparator 77 to operate as ΔΣ stage 72 ). In this way, circuit 230 may detect and recover from fault conditions irrespective of the type and amplitude of input signal V IN . As shown in FIG. 3B, to operate as a mean-absolute-detect circuit, the feedback from V OUT to comparator 77 is disconnected. The output signal produced by comparator 77 is a bit stream that represents the polarity of input signal V IN . Comparator 77 may be configured as a polarity detector using any suitable method known in the art (e.g., by connecting a threshold terminal to ground and a sensing terminal (both not shown) to input signal V IN ). When the output of comparator 77 is provided to demodulator 234 (i.e., MDAC 98 ), input signal V IN is multiplied by its own polarity, thus performing an absolute value operation. The resulting signal is fed through lowpass filter 54 which generates an output signal (V OUT ) of the desired polarity (assuming any external stimuli has been removed from the output node). As long as output signal V OUT is the incorrect polarity, ΔΣ stage 76 will remain unstable. Its output will therefore remain at either a logic low or a logic high (depending on its state when the output fault occurred). When this occurs, V 11 and V 12 substantially cancel each other out (at summing node 106 ), and thus output V 13 is substantially equal to the value of V 10 . Alternatively, V 11 and V 12 may be disconnected from summer 106 during fault recovery. When circuit 230 is operating as a mean-absolute-detector, error signal V 4 produced by comparator 77 is the input signal V IN (or a scaled version thereof). Thus, the output of ΔΣ stage 76 can be monitored (by monitor circuit 73 ) to determine when recovery from an output fault has occurred. For example, when the bit stream produced by ΔΣ stage 76 toggles from one logic state to another, indicating a change in output polarity, circuit 230 has recovered from the fault condition and may be reconfigured back to the RMS-to-DC converter shown in FIG. 3 A. The overall gain of circuit 230 during fault recovery (i.e., mean-absolute-detect mode) does not need to be similar to that of the RMS-to-DC mode (normal operation). However, increased gain during fault recovery does tend to reduce recovery time. Moreover, it will be understood that with certain input waveforms and filter time constants, circuit 230 may go into fault recovery, back to normal operation, and back to fault recovery several times in succession. As long as the output is free of external influences however, circuit 230 will recover. The successive fault mode periods will become shorter in duration until circuit 230 has fully recovered. FIG. 4A illustrates another embodiment of RMS-to-DC converters constructed in accordance with the principles of the present invention. Circuit 330 includes delay stages 82 and 104 and pulse modulator 332 and demodulator 334 . Circuit 330 includes features of circuits 130 and 230 , but substantially eliminates the effect of any DC offset that may occur in ΔΣ stage 76 and delay stage 104 . Modulator 332 includes single-bit reconfigurable ΔΣ stage 72 and ΔΣ stage 76 , delay stage 78 , and subtractor 80 . Demodulator 334 includes 1-bit DAC 87 , 1.5-bit DAC 89 (which may be constructed similar to the DAC formed by buffers 92 and 94 and switch 96 ), subtractor 90 , and multiply-by-two stage 97 . Delay stage 82 matches the delay through reconfigurable ΔΣ modulator 72 and delay stage 104 matches the delay through ΔΣ modulator 76 . Reconfigurable ΔΣ stage 72 provides a quantized output V 1e equal to (assuming gain B=1): V 1  e  [ i ] = V IN  [ i - 1 ] + e  [ i ] - e  [ i - 1 ] V OUT ( 29 ) ΔΣ stage 76 , delay stage 78 and subtractor 80 provide an output V 1f equal to an estimate of the spectrally-shaped quantization error V 4 of reconfigurable ΔΣ stage 72 divided by V OUT . ΔΣ stage 76 provides an output V 15 equal to (assuming gain B=1): V 15  [ i + 1 ] = ( 1 V OUT ) × [ e  [ i ] + ( e ′  [ i + 1 ] - e ′  [ i ] ) ] ( 30 ) where e′[i] is the quantization error of ΔΣ stage 76 . Delay stage 78 and subtractor 80 form a digital differentiator that provide an output V 1f equal to (assuming gain B=1): V 1  f  [ i + 1 ] = ( 1 V OUT ) × [ e 1 + e 2 ] ( 31 ) where e 1 =e[i]−e[i −1]  (32a) e 2 =e′[i +1]−2 e′[i]+e′[i −1]  (32b) V 16 equals (assuming gain B=1): V 16  [ i ] =    V IN  [ i - 1 ] V OUT × V 1  e  [ i ]    ( 33  a ) =    V IN  [ i - 1 ] V OUT × ( V IN  [ i - 1 ] + e 1 )    ( 33  b ) V 17 equals (assuming gain B=1): V 17  [ i + 1 ] = V IN  [ i - 1 ] V OUT × ( e 1 + e 2 ) ( 34 ) The digital differentiator formed by delay stage 78 and subtractor 80 has a zero at DC, and therefore sequence V 1f substantially has no DC component. As a result, sequence V 17 is substantially free of any DC offset introduced by delay stages 82 and 104 , and ΔΣ stage 76 . Subtractor 90 provides an output V 18 that equals the difference between V 16 and V 17 : V 18  [ i + 1 ] =    V 16  [ i ] - V 17  [ i + 1 ]    ( 35  a ) =    V IN  [ i - 1 ] 2 V OUT - V IN V OUT × e 2    ( 35  b ) Thus, V 18 is proportional to V IN squared divided by V OUT , substantially without the quantization noise of Δ−Σ stage 72 . Output V 19 of lowpass filter 54 approximately equals: V 19 ≈ V IN 2 _ ( 36 ) and output V OUT of gain stage 36 approximately equals (assuming gain A=1): V OUT ≈ V IN 2 _ ( 37 ) The circuit of FIG. 4A may be implemented using single-ended or differential circuitry. During operation, output signals from reconfigurable ΔΣ stage 72 may pass through monitor circuit 73 to MDAC 87 . As mentioned above, when V OUT changes polarity, ΔΣ stages 72 and 76 become unstable, producing a string of output signals with a constant logic level. Monitor circuit 73 detects this output string, which it interprets as a “fault condition” and generates a control signal that causes circuit 330 to switch from RMS-to-DC conversion mode to fault recovery mode. In fault recovery mode, switch 75 is opened, breaking the feedback path from output V OUT to ΔΣ stage 72 . Additionally, some components within ΔΣ stage 72 are reconfigured so that ΔΣ stage 72 functions as a comparator circuit rather than as a modulator circuit (shown as comparator circuit 77 in FIG. 4 B). In this arrangement, shown in FIG. 4B, circuit 330 operates as a mean-absolute-detect circuit instead of an RMS-to-DC converter. Circuit 330 thus determines the average of the absolute value of the input signal. Although this measurement is less meaningful than the RMS value of the input signal, it ensures circuit 330 will produce an output signal V OUT that has the proper polarity. Once V OUT returns to the proper polarity, the bit stream produced by comparator 77 toggles, indicating that the fault condition has cleared. Monitor circuit 73 detects this change of logic level and returns circuit 330 back to RMS-to-DC conversion mode (i.e., closes switch 75 and reconfigures comparator 77 to operate as ΔΣ stage 72 ). In this way, circuit 330 may detect and recover from fault conditions irrespective of the type and amplitude of input signal V IN . As shown in FIG. 4B, to operate as a mean-absolute-detect circuit, the feedback from V OUT to comparator 77 is disconnected. The output signal produced by comparator 77 is a bit stream that represents the polarity of input signal V IN . Comparator 77 may be configured as a polarity detector using any suitable method known in the art (e.g., by connecting a threshold terminal to ground and a sensing terminal (both not shown) to input signal V IN ). When the output of comparator 77 is provided to demodulator 334 (i.e., MDAC 87 ), input signal V IN is multiplied by its own polarity, thus performing an absolute value operation. The resulting signal is fed through lowpass filter 54 which generates an output signal (V OUT ) of the desired polarity (assuming any external stimuli has been removed from the output node). As long as output signal V OUT is the incorrect polarity, ΔΣ stage 76 will remain unstable. Its output will therefore remain at either a logic low or a logic high (depending on its state when the output fault occurred). In this case, subtractor 80 will have a substantially zero output and will not affect the value of V OUT . When circuit 330 is operating as a mean-absolute-detect circuit, error signal V 4 produced by comparator 77 is the input signal V IN (or a scaled version thereof). Thus, the output of ΔΣ stage 76 can be monitored (by monitor circuit 73 ) to determine when recovery from an output fault has occurred. For example, when the bit stream produced by ΔΣ stage 76 toggles from one logic state to another, indicating the output has changed polarity, circuit 330 has recovered from the fault condition and may be reconfigured back to the RMS-to-DC converter shown in FIG. 4 A. The overall gain of circuit 330 during fault recovery (i.e., mean-absolute-detect mode) does not need to be similar to that of the RMS-to-DC mode (normal operation). However, increased gain during fault recovery does tend to reduce recovery time. Moreover, it will be understood that with certain input waveforms and filter time constants, circuit 330 may go into fault recovery, back to normal operation, and back to fault recovery several times in succession. As long as the output is free of external influences however, circuit 330 will recover. The successive fault mode periods will become shorter in duration until circuit 330 has fully recovered. As mentioned above, monitoring circuit 73 may detect an output fault by detecting a string of same logic level output bits from reconfigurable ΔΣ stage 72 . This will occur anytime reconfigurable ΔΣ stage 72 is overloaded, either because it is unstable or because the input signal V IN is excessively large. Thus, under certain circumstances a fault condition may be detected even when the output signal V OUT is the “correct” polarity. One such case is when the amplitude of the input signal (V IN ) increases suddenly. For example, a step change of about a factor of ten may cause reconfigurable ΔΣ stage 72 to overload and produce an output duty cycle of either 0% or 100% at the peaks of the input waveform. This result is acceptable and even desirable because it tends to decrease the output response time. Another case during which a fault condition may be detected is when input signal V IN has a large peak value with respect to the DC level of the output signal V OUT (e.g., this may occur with input signals V IN having a high crest factor). Such an input signal may, during its peak, cause reconfigurable ΔΣ stage 72 to produce an output having a duty cycle of either 0% or 100%. Depending on the duration of the peak and the length of the output string detected by monitor circuit 73 , this may initiate entry into the fault recovery mode of operation. This will increase the magnitude of the output signal V OUT during a time when it otherwise would be underestimated. FIG. 5 is a schematic diagram of one possible embodiment of reconfigurable ΔΣ stage 72 . In FIG. 5, reconfigurable ΔΣ stage 72 , shown as system 500 , includes switches 501 - 508 , capacitors 510 - 517 , amplifier 518 , and comparator 519 . As mentioned above, system 500 may be configured to operate as either ΔΣ modulator 72 or as comparator 77 , depending on the state (i.e., open or closed) of switches 501 - 508 . When configured as ΔΣ stage 72 , system 500 progresses through essentially two phases of operation, an auto-zero phase and integration phase. In auto-zero phase, switches 501 , 506 , and 508 are closed. In addition, either switches 503 or 504 are closed depending on the output of comparator 519 . For example, if the output of comparator 519 is a logic high, switches 504 may be closed and switches 503 may be open. Alternatively, if the output of comparator 519 is a logic low, switches 504 may be open and switches 503 may be closed. Input voltage V IN is applied to node 520 and node 522 is connected to ground (if desired, node 522 may be used as a differential input). In the arrangement shown, capacitor 510 is charged to the value of input voltage V IN , and capacitor 511 is set to ground. Assuming for the sake of illustration, that switches 503 are closed and switches 504 are open, capacitor 512 is charged to the value of V OUT and capacitor 513 is set to ground. Closing switches 506 provides a feedback path from outputs 532 and 536 of amplifier 518 to inputs 530 and 534 , respectively. This sets the gain of amplifier 518 , which is preferably a differential transconductance amplifier, to unity. At this point, system 500 has acquired the values of both the input and output voltages and is ready to proceed to the integration phase of operation. In the integration phase, switches 501 and 506 are opened and switches 502 and 505 are closed, configuring amplifier 518 as an integrator. Furthermore, the state of switches 503 or 504 are interchanged. That is, if switches 503 were closed and switches 504 were open during auto-zero, switches 503 open and switches 504 close during integration (and vice versa). This transfers the charge from capacitors 510 - 513 to capacitors 515 and 516 , respectively. Thus, the resulting charge on capacitors 515 and 516 is now equal to the transferred charge plus any charge from the previous integration phase. Amplifier 518 generates a differential output at terminals 532 and 536 which is a function of the result of the previous integration phase, the value of V IN and V OUT , and the output state of comparator 519 . Comparator 519 , which is preferably a latching comparator, compares these values and generates an output signal based on the comparison. When configured as comparator stage 77 , system 500 also operates in essentially two phases of operation, an auto-zero phase and a sample and hold phase. In auto-zero phase, switches 501 , 506 , and 508 are closed. In addition, either switches 503 or 504 are closed. Input voltage V IN is applied to node 520 and node 522 is connected to ground. In this arrangement, capacitor 510 is charged to the value of input voltage V IN , and capacitor 511 is set to ground. Closing switches 506 provides a feedback path from outputs 532 and 536 of amplifier 518 to inputs 530 and 534 , respectively. This sets the gain of amplifier 518 to unity. At this point, system 500 has acquired the values of both the input and output voltages and is ready to proceed to the sample and hold phase of operation. In the sample and hold phase, switches 501 and 506 are opened and switches 502 and 507 are closed, configuring amplifier 518 as a buffer. In this mode the state of switches 503 or 504 are preferably not interchanged. The charge from capacitors 510 and 511 (but not 512 and 513 ) is transferred to capacitors 514 and 517 , respectively. Thus, the resulting charge on capacitors 514 and 517 is now substantially equal to the input voltage V IN . Amplifier 518 generates a differential output at terminals 532 and 536 based on V IN , which is provided to input terminals 540 and 542 of comparator 519 . Comparator 519 compares these values and generates an output signal based on the comparison. Persons skilled in the art will recognize that the apparatus of the present invention may be implemented using circuit configurations other than those shown and discussed above. All such modifications are within the scope of the present invention, which is limited only by the claims that follow.

A circuit that provides the root-mean-square (RMS) value of an input signal and that detects and independently recovers from an output fault condition is provided. The circuit includes reconfigurable circuitry that changes from normal operating mode to fault recovery mode when an output fault is detected. During fault recovery mode, the circuit provides a modified output signal that allows independent recovery from an output fault condition. Once recovery is complete, the circuit returns to normal operating mode and provides a DC output signal proportional to the RMS value of an AC input signal.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to customer response networks and in particular to internet based response networks. 2. Description of the Related Art Many companies establish and maintain home pages on the Internet's World Wide Web. These home pages may provide an electronic market place to users with a computer, appropriate software and internet access. Companies may set up layered directories that provide information in the form of electronic catalogs or brochures. Often a point of contact such as a telephone number or electronic mail address is provided as a link in the event a user requires more information or has a question for the company. Current data services on the Web are interactive in the sense that information content is provided to a user based on keyboard or mouse input from that user. However, this response is limited to pre-programmed or “canned” text, video and/or audio. Typically, web pages contain an e-mail address where a potential customer may send a question or ask for more information on a particular subject of interest. A response to such an inquiry may take anywhere from minutes to days. Even then, there is no assurance that the e-mailed inquiry will reach the appropriate person within the company. In another scenario, a potential customer may obtain the company's telephone number from the web page or from directory assistance. The potential customer then places a telephone call to the company and may spend an interminable length of time on hold waiting for a customer service representative to become available. If the company number is a WATS line (usually referred to as 800 service), the company incurs a significant cost per minute for the amount of time the customer is in the call waiting queue. On the other hand, if the call is a standard toll call, the customer may incur a significant charge while waiting for his/her call to be routed to an available customer service representative. There is accordingly a need for a new method and apparatus to provide queuing capability between a user and a company's representative in order to facilitate the transfer of information in an effective real-time manner. As services migrate to higher bandwidth requirements and capabilities there is an increasing demand for interactive audio sessions over the internet itself. There is accordingly an additional need for a new method and apparatus to provide an interactive live video session capability between a user and a company's representative in order to facilitate the transfer of information in an effective real-time manner. SUMMARY OF THE INVENTION The method and apparatus of the present invention is accomplished by having a customer or user situated at one of many user computer terminals connected to the Internet. The user accesses a company's World Wide Web Internet home page in an Internet session and decides that more information is needed and would appreciate receiving a telephone call from a live customer service representative. The user presses an appropriate keyboard or mouse clicks on an appropriately labeled button on the Web page. An automatic call distribution device submits the user's IP address and pertinent information from the session to a customer service queue for routing to the next available customer service representative. A voice call over the Internet is then established. When the call request by the user to the customer service representative is submitted, session control passes back to the web page server and a normal interactive session is resumed. The customer then continues his previous activities while awaiting a voice call from the next available customer service representative over the internet. One advantage of the present invention allows the user and customer service representative to conduct an interactive audio session. Another advantage of the present invention allows the user and customer service representative to conduct an interactive audio session while not tying up scarce resources waiting for a customer service representative to become available. Still another advantage of the present invention is the elimination of the toll charges associated with a separate telephone call over the public switched telephone network (PSTN). Further features of the above-described invention will become apparent from the detailed description hereinafter. The foregoing features together with certain other features described hereinafter enable the overall system to have properties differing not just by a matter of degree from any related art, but offering an order of magnitude more efficient use of processing time and resources. Additional features and advantages of the invention will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the apparatus and method according to the invention and, together with the description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a block diagram of the data network of the present invention. FIG. 2 illustrates a block diagram of the multimedia response server of the present invention. FIG. 3 illustrates a flowchart depiction of the methodology of the present invention. DETAILED DESCRIPTION Referring now to FIG. 1, the data network 100 of the present invention will now be discussed. A customer or user is situated at one of many user terminals 102 , 106 , 110 , 136 , 138 which may be a personal computer, graphic enhanced mobile device such as a laptop PC, Java phone or a personal digital assistant (PDA). The customer may be connected via an analog or digital (Integrated Services Digital Network (ISDN) or XDSL) connection to a Class 5 (local telephone switching) office 108 , which in turn is connected to a tandem switch 114 . Tandem switch 114 is capable of making both local and toll (long distance) telephone connections and is connected through modem 120 , direct connection or ISDN 118 connection to Asynchronous Transfer Mode (ATM) interface 128 . ATM interface 128 is connected to ATM backbone 130 . ATM backbone 130 supplies the interconnections and transport mechanisms of the data communications network, or Internet of the preferred embodiment. These transport mechanisms are well known and thus need not be further explained here. Customers are also connected through terminals 136 , 138 to the Internet embodied by ATM backbone 130 through Local Area Network (LAN) 134 . LAN direct connectivity is an alternative to dial-up connections. A live person acting as a Company's agent or customer service representative is stationed at agent terminal 124 . Terminal 124 contains an autodialer which automatically dials a preprogrammed or an entered telephone number from telephone 122 . This telephone number is the telephone number of the customer who has entered his/her own telephone number sometime during a Web page access session. The telephone call placed by the Customer service agent located at terminal 124 through telephone 122 is switched through tandem switch 116 to class 5 central office 108 to the customer. In an alternative embodiment, a customer may be connected through a mobile terminal via a wireless data link provided by a cellular, PCS or other wireless service provider. Corporate Web Server 132 is connected to ATM backbone 130 through a direct connection. In an alternate embodiment, the corporate Web Server, stationary or mobile, may also be connected via a similar wireless data link interfaced to the Internet. Referring now to FIG. 2, Corporate Web Server 200 will now be discussed in further detail. Multimedia response server 210 is connected to the Internet 230 via ATM link 228 . ATM link 228 is typically either across a T-3 carrier operating at approximately 44 MHz or is an OC-48 (or higher) Synchronous Optical Network (SONET) connection. The details of such connections are well known and need not be discussed further. The T-3 interconnection 228 interconnects with Multimedia Response Server 210 at the communication channel switch 214 . Communication channel switch 214 is controlled by Web page server 222 . Also connected to communication channel switch 214 are the Automatic Call Distribution (ACD) unit 212 , video server 216 and multiple multimedia operator consoles 202 , 204 , 206 . Communication channel switch 214 is a Northern Telecom Magellan, Vector or other suitable switch. Web page server 222 operates to supply content to customers who access the Web page, controls connections to and from communication channel switch 214 . Video server 216 supplies high bandwidth video to customers accessing the Web page through communication channel switch 214 . Automatic Call Distribution (ACD) 212 unit operates by transferring customer information such as telephone number or Internet Protocol (IP) address and subject of the further information requested into a queue for service by the next available operator stationed at one of the multimedia operator consoles 202 , 204 , 206 . A customer who is accessing the Web page on the Web server typically mouse clicks on a hot button or link found on the Web page. This link is identified as a channel for selecting a live interactive call-back session with a human operator. Upon availability of the human operator at one of the multiple multimedia operator consoles 202 , 204 , 206 the interactive call-back session is initiated over the internet to the IP address previously placed in the queue. Upon the successful connection of the call between the customer service representative and the customer, an interactive audio session over the network is conducted. Upon termination of the interactive audio session, the connection is taken down and the next queued interactive audio session is initiated. Multimedia operator consoles 202 , 204 , 206 and customer terminals 102 , 106 , 110 , 136 , 136 are equipped with appropriate multimedia equipment and software. Typical equipment includes commercial off the shelf microphones/headsets with speakers, digital signal processor based peripheral sound cards, and a video camera with its video interface to the terminals and consoles. When the customer initiates the interactive multimedia session the content of the customer's screen is accessible by the agent on the multimedia operator console. The session participants in one embodiment are also able to view each other through the video camera output portion of the link and are able to converse audibly to conduct business. The customer agent is able to see exactly what the customer is trying to describe and is therefore capable of answering questions and solving problems in a much more time efficient manner without tying up more resources. The customer agent is able to diagnose conditions and problems on a customer's computer in real-time or near real-time and can download software to determine configurations, correct errors, modify settings and add or delete software modules as desired. Of course, the multimedia response server automates many of these functions and does not require a human customer agent in many of these situations. Referring now to FIG. 3, the methodology 300 of the present invention will now be discussed. The process begins in step 302 with the program Start function. In step 304 , the Web server makes the Web page available to customers over the Internet or any other suitable public or private data network. A Customer accesses the Web page from his/her computer terminal using the appropriate physical connection and software. As an example, if the Web page is for a travel agent, the customer could search for airline flights to a desired destination at a particular time and for a particular price. If the specific parameters defined do not result in a satisfactory result for the customer, or if at any time during a session live human interaction is desired or required, then the customer clicks on the graphical hot button or link (step 306 ) and optionally is prompted to enter his name, phone number and a description of the subject in question, if this information is not already available. The IP address is transferred in step 308 by an automatic distribution mechanism into a call-back queue via the above described invention and a live call-back session in step 310 is conducted in an effort to satisfy the customer's request. Upon completion of the session, control passes to step 312 , Stop. Other such embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is readily apparent that the above described invention may be implemented in other types of data networks, public and private, including an intranet or an internet, whereby these terms denote an either an internal network of computers or any internetworking of communication devices. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

An interactive data communication user is connected through a network to a multimedia response server. The user presses an appropriate keyboard or mouse clicks on an appropriately labeled button on a data page. An automatic call distribution device switches the session to a customer service queue for routing to the next available customer service representative. The customer service representative automatically places a internet based telephone call to the user. When the interactive session between the user and the customer service representative is completed, session control passes back to the data page server and a normal interactive session is resumed.

CROSS REFERENCE TO RELATED APPLICATION This application is based on Japanese Patent Application No. 2006-219477 filed on Aug. 11, 2006, the disclosure of which is incorporated herein by reference. FIELD OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device. BACKGROUND OF THE INVENTION Heretofore, there has been known a semiconductor device in which a super-junction structure is adopted for, for example, a power MOS transistor of vertical type. The “super-junction structure” is a configuration in which N type layers and P type layers to serve as a drift region are alternately arranged in the planar direction of a substrate. Owing to the adoption of such a structure, an electric field from a source toward a drain is also directed from the N type layers to the P type layers. Accordingly, the electric field can be prevented from concentrating in one place between the source and the drain, and in turn, the prevention of insulation breakdown can be attained. Besides, as the width “dn” of each N type layer and the width “dp” of each P type layer are smaller, the concentrations of the respective layers can be made higher, and the ON-resistance of the semiconductor device can be made lower. Further, as the thicknesses of the respective layers are larger, a higher withstand voltage can be realized. A method for forming the semiconductor device having the super-junction structure as stated above has been proposed in, for example, Patent Document 1 (JP-A-2005-317905 corresponding to USP Application Publication No. 2005/221547) and Patent Document 2 (JP-A-2005-294711 corresponding to EP 1734565-A1). Concretely, Patent Documents 1 and 2 have proposed the method wherein an N+ type substrate on which an epitaxial layer of N type is formed is prepared, and after trenches are formed in the substrate, epitaxial layers of P type are buried into the trenches, and the front surface of the substrate is flattened and polished, thereby to form the repeated structure of P type regions and N type regions. When it is intended to lower the ON-resistance of the semiconductor device and to heighten the withstand voltage thereof, in the case of adopting the super-junction structure for the MOS transistor as stated above, it is considered to make smaller the width dn of each N type layer and the width dp of each P type layer and to make the respective layers thicker, as described above. However, when it is intended to realize the lower ON-resistance and the higher withstand voltage, it has been revealed by the inventors that problems to be stated below are posed. As the first problem, for the purpose of manufacturing a device portion of high withstand voltage, the epitaxial layer of the N type on the N+ type substrate needs to be thickened. By way of example, the thickness of the N type epitaxial layer needs to be at least 30 μm for a withstand voltage of 600 V, and it needs to be at least 60 μm for a withstand voltage of 1200 V. In order to obtain such a large thickness, film formation for a long time is required, and a process cost becomes high. Besides, as the second problem, when both the high withstand voltage and the low ON-resistance are to be attained, the widths dn and dp of the respective epitaxial layers of the N type and P type need to be made small so as to heighten the concentrations of the respective layers, and the respective layers need to be thickened. However, when the trench is narrowed in order to make small the width of, for example, the P type epitaxial layer, the P type epitaxial layer formed earlier at the opening part of the trench closes up this opening part of the trench, to incur the problem that the P type epitaxial layer is not formed at the bottom of the trench. Thus, a cavity appears within the trench, and the interior of the trench is not completely filled up with the P type epitaxial layer. In this case, in order to prevent the cavity from appearing, it is considered to bury the epitaxial layer from the bottom part of the trench. However, a long time is expended on film formation, and a process cost becomes high. Further, as the third problem, for the purpose of realizing the high withstand voltage, the balance of (concentration×thickness), i.e., charge balance, needs to be adjusted in each of the layers. That is, the value of (concentration×dp) in the P type epitaxial layer and the value of (concentration×dn) in the N type epitaxial layer must be brought into coincidence. However, in forming the P type epitaxial layer within the trench, impurity ions migrate from the N+ type substrate into the P type epitaxial layer being formed, on account of an outward diffusion, and the concentration of the P type epitaxial layer deviates from a target value. It is accordingly difficult to adjust the concentrations and thicknesses of the respective layers so as to satisfy the charge balance. Thus, it is required to form epitaxial layers constituting a super-junction structure, in a short time, thereby to curtail a manufacturing cost. Further, it is required to make smaller the widths of epitaxial layers constituting a super-junction structure, thereby to attain the higher withstand voltage and lower ON-resistance of a semiconductor device. Furthermore, it is required to attain a charge balance in respective layers constituting a super-junction structure, for the purpose of ensuring a high withstand voltage. SUMMARY OF THE INVENTION In view of the above-described problem, it is an object of the present disclosure to provide a method for manufacturing a semiconductor device. According to a first aspect of the present disclosure, a method for manufacturing a semiconductor device includes: forming a plurality of trenches on a first side of a semiconductor substrate, wherein the substrate has a first conductive type; forming a second conductive type semiconductor film in each trench so that the substrate between two adjacent trenches provides a first column, and the second conductive type semiconductor film in each trench provides a second column, wherein the first and second columns are alternately repeated along with a predetermined direction in parallel to the first side of the substrate; thinning a second side of the substrate, the second side being opposite to the first side; and increasing an impurity concentration of the first conductive type in a thinned second side of the substrate so that a first conductive type layer is provided. The impurity concentration of the first conductive type layer is higher than an impurity concentration of the first column. The first column provides a drift layer so that a vertical type first-conductive-type channel transistor is formed. In the above method, since the substrate having the first conductive type provides the first column, it is not necessary to form the first column on a support substrate. Thus, a manufacturing time and a manufacturing cost are reduced. Further, since the step of increasing the impurity concentration of the first conductive type layer is performed after the step of forming the second conductive type semiconductor film in each trench, diffusion from the substrate to the second conductive type semiconductor film is reduced. Thus, the impurity concentration in the second conductive type semiconductor film is sufficiently controlled to be a predetermined value. According to a second aspect of the present disclosure, a method for manufacturing a semiconductor device includes: forming a plurality of trenches on a first side of a semiconductor substrate, wherein the substrate has a first conductive type; forming a second conductive type semiconductor film in each trench so that the substrate between two trenches provides a first column, and the second conductive type semiconductor film in each trench provides a second column, wherein the first and second columns are alternately repeated along with a predetermined direction in parallel to the first side of the substrate; thinning a second side of the substrate, the second side being opposite to the first side; increasing an impurity concentration of a first part of a thinned second side of the substrate so that the first part provides a first conductive type layer; and reforming a second part of the thinned second side of the substrate so that the second part provides a second conductive type layer. The first part of the thinned second side is adjacent to the second part of the thinned second side. The impurity concentration of the first conductive type layer is higher than an impurity concentration of the first column. The impurity concentration of the second conductive type layer is higher than an impurity concentration of the second column. The first column on the first part of the thinned second side provides a drift layer so that a vertical type first-conductive-type channel transistor is formed. The second column on the second part of the thinned second side provides a drift layer so that a vertical type second-conductive-type channel transistor is formed. In the above method, the vertical type first-conductive-type channel transistor and the vertical type second-conductive-type channel transistor are manufacturing by preparing the substrate having the first conductive type. Thus, it is not necessary to form the first column on a support substrate, so that a manufacturing time and a manufacturing cost are reduced. Further, diffusion from the substrate to the second conductive type semiconductor film is reduced. Thus, the impurity concentration in the second conductive type semiconductor film is sufficiently controlled to be a predetermined value. According to a third aspect of the present disclosure, a method for manufacturing a semiconductor device includes: forming a plurality of trenches on a first side of a semiconductor substrate, wherein the substrate has a first conductive type; forming a second conductive type semiconductor film on an inner wall of each trench by an epitaxial growth method in such a manner that a thickness of the second conductive film is equal to or smaller than a half of a width of the trench; forming an oxide film on the second conductive type semiconductor film in each trench so that the trench is filled with the oxide film, wherein the substrate between two trenches provides a first column, and the second conductive type semiconductor film in each trench provides a second column, and wherein the first and second columns are alternately repeated along with a predetermined direction in parallel to the first side of the substrate; thinning a second side of the substrate, the second side being opposite to the first side; and increasing an impurity concentration of a thinned second side of the substrate so that a first conductive type layer is provided. An impurity concentration of the first conductive type layer is higher than an impurity concentration of the first column, and the first column provides a drift layer so that a vertical type first-conductive-type channel transistor is formed. In the above method, the width of the second conductive type semiconductor film in each trench becomes smaller, so that an on-state resistance related to the second conductive type semiconductor film is reduced. Further, a manufacturing time and a manufacturing cost are reduced. Furthermore, the impurity concentration in the second conductive type semiconductor film is sufficiently controlled to be a predetermined value. According to a fourth aspect of the present disclosure, a method for manufacturing a semiconductor device includes: forming a plurality of trenches on a first side of a semiconductor substrate, wherein the substrate has a first conductive type; forming a second conductive type semiconductor region on an inner wall of each trench by diffusing atoms in vapor phase or implanting ions into the inner wall of the trench; forming an oxide film on the second conductive type semiconductor region in each trench so that the trench is filled with the oxide film, wherein the substrate between two trenches provides a first column, and the second conductive type semiconductor region in each trench provides a second column, wherein the first and second columns are alternately repeated along with a predetermined direction in parallel to the first side of the substrate; thinning a second side of the substrate, the second side being opposite to the first side; and increasing an impurity concentration of a thinned second side of the substrate so that a first conductive type layer is provided. An impurity concentration of the first conductive type layer is higher than an impurity concentration of the first column, and the first column provides a drift layer so that a vertical type first-conductive-type channel transistor is formed. In the above method, a manufacturing time and a manufacturing cost are reduced, and the impurity concentration in the second conductive type semiconductor region is sufficiently controlled to be a predetermined value. According to a fifth aspect of the present disclosure, a method for manufacturing a semiconductor device includes: forming a plurality of trenches on a first side of a semiconductor substrate, wherein the substrate has a first conductive type; forming a first conductive type semiconductor region on an inner wall of each trench by diffusing atoms in vapor phase or implanting ions into the inner wall of the trench, wherein an impurity concentration of the first conductive type semiconductor region is higher than an impurity concentration of the substrate, and wherein the substrate between the first conductive type semiconductor region in adjacent two trenches and the first conductive type semiconductor region in the adjacent two trenches provide a first column; forming a second conductive type semiconductor film on the first conductive type semiconductor region in each trench so that the second conductive type semiconductor film in each trench provides a second column, wherein the first and second columns are alternately repeated along with a predetermined direction in parallel to the first side of the substrate; thinning a second side of the substrate, the second side being opposite to the first side; and increasing an impurity concentration of a thinned second side of the substrate so that a first conductive type layer is provided, wherein the impurity concentration of the first conductive type layer is higher than an impurity concentration of the first conductive type semiconductor region. A part of the substrate disposed on a periphery of the substrate provides a periphery layer, and the first column provides a drift layer so that a vertical type first-conductive-type channel transistor is formed. In the above method, a manufacturing time and a manufacturing cost are reduced, and the impurity concentration in the second conductive type semiconductor film is sufficiently controlled to be a predetermined value. Further, the substrate provides the periphery layer as a terminal end of the device. According to a sixth aspect of the present disclosure, a method for manufacturing a semiconductor device includes: forming a plurality of trenches on a first side of a semiconductor substrate, wherein the substrate has a first conductive type; forming a first conductive type semiconductor region on an inner wall of each trench by an epitaxial growth method, wherein an impurity concentration of the first conductive type semiconductor region is higher than an impurity concentration of the substrate, and wherein the substrate between adjacent two trenches and the first conductive type semiconductor region in the adjacent two trenches provide a first column; forming a second conductive type semiconductor film on the first conductive type semiconductor region in each trench so that the second conductive type semiconductor film in each trench provides a second column, wherein the first and second columns are alternately repeated along with a predetermined direction in parallel to the first side of the substrate; thinning a second side of the substrate, the second side being opposite to the first side; and increasing an impurity concentration of a thinned second side of the substrate so that a first conductive type layer is provided, wherein the impurity concentration of the first conductive type layer is higher than an impurity concentration of the first conductive type semiconductor region. A part of the substrate disposed on a periphery of the substrate provides a periphery layer, and the first column provides a drift layer so that a vertical type first-conductive-type channel transistor is formed. In the above method, the first conductive type semiconductor region is formed on the inner wall of each trench by the epitaxial growth method, and the second conductive type semiconductor film is formed on the first conductive type semiconductor region in each trench. Thus, the width of the first conductive type semiconductor region and the width of the second conductive type semiconductor film are reduced, respectively. Thus, the on-state resistance of the device is reduced. Further, a manufacturing time and a manufacturing cost are reduced, and the impurity concentration in the second conductive type semiconductor film is sufficiently controlled to be a predetermined value. Further, the substrate provides the periphery layer as a terminal end of the device. According to a seventh aspect of the present disclosure, a method for manufacturing a semiconductor device includes: forming a plurality of trenches on a first side of a semiconductor substrate, wherein the substrate has a first conductive type; forming a first conductive type semiconductor region on an inner wall of each trench by diffusing atoms in vapor phase or implanting ions into the inner wall of the trench, wherein an impurity concentration of the first conductive type semiconductor region is higher than an impurity concentration of the substrate, and wherein the substrate between the first conductive type semiconductor region in adjacent two trenches and the first conductive type semiconductor region in the adjacent two trenches provide a first column; forming a second conductive type semiconductor film on the first conductive type semiconductor region in each trench by an epitaxial growth method; forming an oxide film on the second conductive type semiconductor film in each trench so that the trench is filled with the oxide film, wherein the second conductive type semiconductor film in each trench provides a second column, and wherein the first and second columns are alternately repeated along with a predetermined direction in parallel to the first side of the substrate; thinning a second side of the substrate, the second side being opposite to the first side; and increasing an impurity concentration of a thinned second side of the substrate so that a first conductive type layer is provided, wherein the impurity concentration of the first conductive type layer is higher than an impurity concentration of the first conductive type semiconductor region. A part of the substrate disposed on a periphery of the substrate provides a periphery layer. The first column provides a drift layer so that a vertical type first-conductive-type channel transistor is formed. In the above method, a manufacturing time and a manufacturing cost are reduced, and the impurity concentration in the second conductive type semiconductor film is sufficiently controlled to be a predetermined value. Further, the substrate provides the periphery layer as a terminal end of the device. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings: FIG. 1 is a cross sectional view showing a semiconductor device according to a first embodiment; FIGS. 2A to 2F are cross sectional views showing a method for manufacturing the device shown in FIG. 1 ; FIG. 3 is a cross sectional view showing a semiconductor device according to a second embodiment; FIGS. 4A to 4E are cross sectional views showing a method for manufacturing the device shown in FIG. 3 ; FIG. 5 is a cross sectional view showing a semiconductor device according to a third embodiment; FIGS. 6A to 6D are cross sectional views showing a method for manufacturing the device shown in FIG. 5 ; FIGS. 7A to 7C are cross sectional views showing a method for manufacturing a semiconductor device according to a fourth embodiment; FIG. 8 is a cross sectional view showing a semiconductor device according to a fifth embodiment; FIGS. 9A to 9F are cross sectional views showing a method for manufacturing the device shown in FIG. 8 ; FIG. 10 is a cross sectional view showing a semiconductor device according to a sixth embodiment; FIGS. 11A to 11D are cross sectional views showing a method for manufacturing the device shown in FIG. 10 ; and FIG. 12 is a cross sectional view showing a semiconductor device according to a seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiments to be stated below, an “N type” (including an “N+ type” and an “N− type”) corresponds to a first conductivity type, and a “P type” (including a “P+ type” and a “P− type”) corresponds to a second conductivity type. First Embodiment FIG. 1 is a schematic sectional view of a semiconductor device according to the first embodiment. As shown in FIG. 1 , the semiconductor device is formed with a large number of MOS transistors of N-channel type. An N type layer 2 (corresponding to a first layer of first conductivity type) and a P type layer 3 (corresponding to a first layer of second conductivity type) are formed on an N+ type layer 1 (corresponding to a second layer of the first conductivity type) as drift regions, and a super-junction structure in which the N type layer 2 and P type layer 3 are alternately arranged in the planar direction of the N+ type layer 1 is formed. Besides, a P type channel layer 4 is formed at the front surface layer parts of the N type layer 2 and the P type layer 3 . Further, an N+ type source layer 5 is formed on a side opposing to the N type layer 2 , within the front surface layer part of the P type channel layer 4 , and a P+ type layer 6 is formed on a side opposing to the P type layer 3 . In addition, a trench 7 reaching the N type layer 2 is formed penetrating through the N+ type source layer 5 and the P type channel layer 4 . A gate insulating film 8 and a gate layer 9 are successively formed on the inner wall surface of the trench 7 , and a trench gate structure which consists of the trench 7 , gate insulating film 8 and gate layer 9 is configured. Incidentally, part of the N+ type source layer 5 and the trench gate structure are covered with an insulating film not shown. In addition, unshown electrodes which are electrically connected to the N+ type source layer 5 and the gate layer 9 are respectively formed. Besides, a drain electrode not shown is formed so as to lie in touch with the N+ type layer 1 . The above is the whole configuration of the semiconductor device according to this embodiment. Next, a method for manufacturing the semiconductor device will be described with reference to the drawings. FIGS. 2A to 2F are views showing manufacturing steps for the semiconductor device shown in FIG. 1 . At the step shown in FIG. 2A , an N type substrate 10 (corresponding to a substrate of first conductivity type) is prepared. The N type substrate 10 is a silicon substrate which is doped with As (arsenic), Sb (antimony) or P (phosphorus) as an impurity in a doping quantity of, for example, 1×10 15 cm −3 to 1×10 18 cm −3 . The reason why the lower limit of the doping quantity is set at 1×10 15 cm −3 at this step, is that, at a lower impurity concentration, the doping becomes meaningless. Besides, the reason why the upper limit of the doping quantity is set at 1×10 18 cm −3 is that, at a higher impurity concentration, any depletion layer is not formed. In addition, the impurity concentration of the N type substrate 10 doped with the impurity is measured by, for example, a method of resistivity measurement. At the step shown in FIG. 2B , an oxide film not shown is formed on the front surface of the N type substrate 10 by a method of thermal oxidation or CVD, and the pattern of a part to become a trench 11 is formed by a photolithographic process and an etching process which are well known. In addition, the trench 11 having a depth of 10 μm to 100 μm and a width of 0.1 μm to 5 μm is formed by dry etching or wet etching as an etching process. By the way, in a case where the trench 11 is formed in the N type substrate 10 by the wet etching, it is favorable for the execution of anisotropic etching to adopt a (110) substrate as the N type substrate 10 , and to employ an alkaline etchant such as KOH (potassium hydroxide) or TMAH (tetramethyl ammonium hydroxide). At the step shown in FIG. 2C , a CVD equipment is prepared, and the N type substrate 10 is set in the CVD equipment. Besides, a dopant gas of phosphine, arsine or antimony, and HCL gas for suppressing an epitaxial growth at the upper part of the trench 11 , are caused to flow through a growth gas of silane, dichlorosilane or trichlorosilane. Thus, a P type epitaxial layer 12 is buried in the trench 11 of the N type substrate 10 . On this occasion, using the concentration of the N type substrate 10 measured at the step shown in FIG. 2A , the P type epitaxial layer 12 is formed while the concentration of this P type epitaxial layer 12 is being adjusted so that the product between the width of the P type epitaxial layer 12 (that is, the width of the trench 11 ) and the concentration thereof may become equal to the product between the width of the N type substrate 10 between the trenches 11 (that is, the width of a region to become an N type layer 2 ) and the concentration thereof. In this way, the charge balance between the N type substrate 10 (the region to be configured as the N type layer 2 by a later step) and the P type epitaxial layer 12 can be attained. Further, in forming the P type epitaxial layer 12 , this P type epitaxial layer 12 is buried into the trench 11 without lowering the temperature of the N type substrate 10 stepwise, that is, with the N type substrate 10 held at a constant temperature. Thus, the migrations of impurity ions from the N type substrate 10 into the P type epitaxial layer 12 can be suppressed, and in turn, an outward diffusion can be suppressed. At the step shown in FIG. 2D , the front surface side of the N type substrate 10 is flattened in such a way that polishing based on CMP or etching-back based on dry etching is performed a thickness of about 1 μm from the front surface side of the N type substrate 10 . Thus, the repeated parts of a P type region (the P type epitaxial layer 12 ) and an N type region (the N type substrate 10 ) are denuded on the front surface side of the N type substrate 10 . At the step shown in FIG. 2E , a semiconductor device portion is formed by well-known manufacturing processes. Concretely, a P type channel layer 4 , an N+ source layer 5 and a P+ type layer 6 are formed by a photolithographic process, an ion implantation process and thermal diffusion/annealing processes. Besides, a trench gate structure is formed by a photolithographic process, a dry etching process, a thermal oxidation process and a poly-silicon film formation process. Further, electrodes, wiring lines and a protective film, not shown, are formed on the front surface side of the N type substrate 10 by a photolithographic process, an etching process, a metal film formation process and an insulating film formation process. In this embodiment, the trench gate structure is formed on the N type substrate 10 , whereby a MOS transistor of N channel type is formed. When the device portion has been thus formed, the P type epitaxial layer 12 within the trench 11 is configured as a P type layer 3 shown in FIG. 1 . At the step shown in FIG. 2F , the N type substrate 10 is thinned to a thickness of 30 μm to 120 μm by cutting down the rear surface side of the N type substrate 10 , and an N+ type layer 1 is formed by the ion implantation and diffusion of phosphorus. Thus, that region of the N type substrate 10 which is held between the P type layers 3 is configured as the N type layer 2 . In addition, a drain electrode not shown is formed on the N+ type layer 1 . Thereafter, the substrate having ended the step shown in FIG. 2F is subjected to dicing cut, thereby to be split in the shape of a chip. Then, the semiconductor device shown in FIG. 1 is finished up. As described above, this embodiment features that the N type layer 2 to constitute the super-junction structure is prepared as the N type substrate 10 , that the super-junction structure is formed by employing the N type substrate 10 , and that the N+ type layer 1 is lastly formed. In this manner, the epitaxial layer to become the N type layer 2 is not formed, but the substrate of N type is employed beforehand, whereby the formation of the epitaxial layer for forming the N type layer 2 can be dispensed with. Accordingly, the step of forming the N type layer 2 as the epitaxial layer can be removed, and the shortening of a manufacturing time period and the curtailment of a manufacturing cost can be realized. As compared with the prior-art method in which the epitaxial layer of N type is formed on the substrate of N+ type, the method in which the N+ type layer 1 is formed by the ion implantation and the thermal diffusion as in this embodiment can reduce the number of steps and the attendant process cost and can lower the manufacturing cost. Moreover, since the N type substrate 10 lower in concentration than the N+ type layer 1 is employed, the migrations of the impurity ions from the N type substrate 10 into the P type epitaxial layer 12 being formed, that is, the outward diffusion can be suppressed in the case where the P type epitaxial layer 12 is formed within the trench 11 at the step shown in FIG. 2C . Thus, the charge balance between the respective layers of the P type layer 3 and the N type layer 2 can be easily established, and in turn, a withstand voltage characteristic in the semiconductor device can be enhanced. Second Embodiment In this embodiment, only parts different from the parts of the first embodiment will be described. This embodiment features that, after a device portion has been formed on an N type substrate 10 , a super-junction structure is formed. FIG. 3 is a schematic sectional view of a semiconductor device according to this embodiment. In this embodiment, any P type channel layer 4 is not existent in a P type layer 3 , unlike in the semiconductor device shown in FIG. 1 in the first embodiment. More specifically, a P type channel layer 4 is formed at the front surface layer part of an N type layer 2 , and an N+ type source layer 5 is formed at the front surface layer part of the P type channel layer 4 . In addition, a trench 7 reaching the N type layer 2 is formed penetrating through the N+ type source layer 5 and the P type channel layer 4 . A gate insulating film 8 and a gate layer 9 are successively formed on the inner wall surface of the trench 7 , whereby a trench gate structure is configured. Besides, a P+ type layer 6 is formed at the front surface layer part of the P type layer 3 . The above is the configuration of the semiconductor device according to this embodiment. Next, a method for manufacturing the semiconductor device according to this embodiment will be described with reference to the drawings. FIGS. 4A to 4F are views showing manufacturing steps for the semiconductor device shown in FIG. 3 . In this embodiment, after the step shown in FIG. 2A has been first ended, the trench gate structure of a device portion is formed at the step shown in FIG. 4A . More specifically, a P type channel layer 4 and an N+ source layer 5 are formed by a photolithographic process, an ion implantation process and thermal diffusion/annealing processes. Further, the trench gate structure is formed by a photolithographic process, a dry etching process, a thermal oxidation process and a poly-silicon film formation process. In addition, at the step shown in FIG. 4B , an oxide film not shown is formed on the front surface side of an N type substrate 10 by thermal oxidation or CVD, and the pattern of a part to become a trench 11 is formed by a photolithographic process and an etching process. On this occasion, the oxide film is patterned so that the trenches 11 may be located between the trench gate structures of individual elements. Further, the trench 11 having a depth of 10 μm to 100 μm and a width of 0.1 μm to 5 μm is formed by dry etching or wet etching as an etching process. At the step shown in FIG. 4C , a P type epitaxial layer 12 is buried into the trench 11 in the same way as at the step shown in FIG. 2C . At the step shown in FIG. 4D , the front surface side of the N type substrate 10 is flattened in the same way as at the step shown in FIG. 2D . Further, the unshown electrodes, wiring lines and protective film of a MOS transistor are formed on the front surface side of the N type substrate 10 by a photolithographic process, an etching process, a metal film formation process and an insulating film formation process. At the step shown in FIG. 4E , an N+ type layer 1 is formed in the same way as at the step shown in FIG. 2F . Besides, a P+ type layer 6 is formed at the front surface layer part of a P type layer 3 . In the above way, the semiconductor device shown in FIG. 3 is finished up. As described above, in this embodiment, the device portion is formed earlier, and the P type epitaxial layer 12 to become the P type layer 3 is formed. In this manner, the P type epitaxial layer 12 is formed after the formation of the device portion, so that a heat treatment concerning repeated P-N layers (that is, the repeated structure of the P type layer 3 and an N type layer 2 ) can be relieved. It is therefore possible to keep the concentrations of the P-N layers high and to make an ON-resistance still lower. Third Embodiment In this embodiment, only parts different from the parts of the foregoing embodiments will be described. This embodiment features that a P type layer 3 is not buried completely within a trench 11 , but that in a state where a P type epitaxial layer 12 is formed on the wall surface of the trench 11 , an insulating layer is buried into the P type epitaxial layer 12 conforming to the shape of the trench 11 , thereby to configure a repeated structure which consists of an N type layer 2 and the P type layer 3 formed of the P type epitaxial layer 12 . FIG. 5 is a schematic sectional view of a semiconductor device according to this embodiment. As shown in the figure, in this embodiment, an oxide film 13 and the P type layer 3 are successively formed on the inner wall surface of the trench 11 which is provided in each N type layer 2 formed with a trench gate structure. An SiO 2 film, for example, is adopted as the oxide film 13 . Next, a method for manufacturing the semiconductor device will be described with reference to the drawings. FIGS. 6A to 6D are views showing manufacturing steps for the semiconductor device shown in FIG. 5 . First, the steps shown in FIGS. 2A and 2B are carried out to prepare an N type substrate 10 formed with a trench 11 . Incidentally, also in this embodiment, the impurity concentration of the N type substrate 10 is measured beforehand. In addition, at the step shown in FIG. 6A , a CVD equipment is prepared, and the N type substrate 10 formed with the trench 11 is set in the CVD equipment. Besides, a dopant gas of diborane is caused to flow through a growth gas of silane, dichlorosilane or trichlorosilane. Thus, a P type epitaxial layer 12 is formed on the wall surface of the trench 11 of the N type substrate 10 . On this occasion, the P type epitaxial layer 12 is formed at a thickness of, at most, half of the width of the trench 11 , on this trench 11 . Thus, a width for burying an oxide film 13 can be ensured. Besides, in forming the P type epitaxial layer 12 , this P type epitaxial layer 12 is formed so that the impurity concentration of the P type epitaxial layer 12 may become higher than the impurity concentration of the N type substrate 10 . In other words, the P type epitaxial layer 12 is formed so as to satisfy [(the width of the P type epitaxial layer 12 )×(the impurity concentration of the P type epitaxial layer 12 )>(the width of a part to become an N type layer 2 , in the N type substrate 10 )×(the impurity concentration of the N type substrate 10 measured at the above step)]. Further, the oxide film 13 is buried into the P type epitaxial layer 12 by employing the CVD equipment. Since the step of burying the oxide film 13 can be performed at a low temperature, the oxide film 13 can be easily formed on the P type epitaxial layer 12 . Thereafter, at the step shown in FIG. 6B , that part of the oxide film 13 which is formed on the P type epitaxial layer 12 on the front surface side of the N type substrate 10 is removed by dry etching, and the P type epitaxial layer 12 at the front surface of the N type substrate 10 is flattened by dry etching or polishing based on CMP. At the step shown in FIG. 6C , a device portion is formed on the N type substrate 10 in the same way as at the step shown in FIG. 2E . When the device portion has been thus formed, the P type epitaxial layer 12 within the trench 11 is configured as a P type layer 3 shown in FIG. 5 . In forming the device portion at this step, a configuration up to a trench gate structure is formed. In addition, the withstand voltage of the device portion is measured. In this embodiment, the withstand voltage measurement is performed, for example, in such a way that probes are pushed against the electrode parts of the device portion, and that a voltage is applied between the source and drain of the device portion. In a case where the value of the withstand voltage measured in this way is lower than a supposed value (reference value), the N+ type substrate is heat-treated, whereby the boron of the P type layer 3 is absorbed out into the oxide film 13 so as to lower the concentration of the P type layer 3 , by utilizing the difference between the segregation coefficients of boron in the oxide film 13 and in silicon forming the N type substrate 10 . Thus, a charge balance can be adjusted, and the withstand voltage of the device portion can be adjusted to a target value. Accordingly, in order to facilitate the charge balance adjustment by absorbing out the impurity ions of the P type layer 3 into the oxide film 13 at this step, the impurity concentration of the P type epitaxial layer 12 should preferably be made somewhat high beforehand at the step shown in FIG. 6A . Besides, after the charge balance has been adjusted, the unshown electrodes, wiring lines and protective film of the device portion are formed on the front surface side of the N type substrate 10 at this step. By the way, in a case where the target value has been obtained as the withstand voltage of the device portion by the withstand voltage measurement, the heat treatment need not be performed. Therefore, after the electrodes etc. of the device portion have been formed, the manufacturing method proceeds to the next step. In addition, at the step shown in FIG. 6D , an N+ type layer 1 is formed in the same way as at the step shown in FIG. 2F . Thus, the semiconductor device shown in FIG. 5 is finished up. As described above, this embodiment features that, in forming the P type epitaxial layer 12 , this P type epitaxial layer 12 is formed at the thickness of, at most, half of the width of the trench 11 . Thus, the width of the P type layer 3 can be made small, and the impurity concentration of the P type layer 3 can be consequently set higher than that of the N type substrate 10 . Besides, since the width of the P type layer 3 can be made small, the ON-resistance of the device portion can be lowered. Moreover, the P type epitaxial layer 12 is formed beforehand so as to have the impurity concentration higher than that of the N type substrate 10 , whereby after the formation of the device portion, the impurity ions of the P type epitaxial layer 12 can be absorbed out into the oxide film 13 so as to adjust the charge balance. Thus, the withstand voltage of the device portion can be held at a high available percentage. In this embodiment, in the same manner as in the foregoing embodiments, the N type substrate 10 is employed as the substrate for manufacturing the semiconductor device. As stated before, therefore, it is possible to relieve the manufacturing process of the epitaxial layer and to curtail the manufacturing cost of the semiconductor device. Fourth Embodiment In this embodiment, only parts different from the parts of the foregoing embodiments will be described. This embodiment features that, in manufacturing the semiconductor device shown in FIG. 5 , a device portion is formed earlier, whereupon a super-junction structure is formed. FIGS. 7A to 7C are views showing manufacturing steps for the semiconductor device shown in FIG. 5 . First, the steps shown in FIG. 4B are carried out, thereby to prepare an N type substrate 10 which is formed with the device portion and provided with a trench 11 . Incidentally, also in this embodiment, the impurity concentration of the N type substrate 10 is measured beforehand. At the step shown in FIG. 7A , an oxide film 14 is formed at a part formed with the device portion, in the front surface side of the N type substrate 10 (at a part except the opening of the trench 11 ). Thereafter, a P type epitaxial layer 12 and an oxide film 13 are formed in the same way as at the step shown in FIG. 6A . At the step shown in FIG. 7B , the oxide film 13 , P type epitaxial layer 12 and oxide film 14 which are formed on the front surface side of the N type substrate 10 are removed, for example, in the same way as at the step shown in FIG. 6B , whereby the front surface side of the N type substrate 10 is flattened. Besides, in the same manner as in the third embodiment, the withstand voltage of the device portion is measured, and the N type substrate 10 is heat-treated when the withstand voltage deviates from its target value, whereby a charge balance is attained. At the step shown in FIG. 7C , a P+ type layer 6 is formed at the front surface layer part of a P type layer 3 . Besides, an N+ type layer 1 is formed in the same way as at the step shown in FIG. 2F . Thereafter, the unshown electrodes etc. of the device portion are formed, whereby the semiconductor device shown in FIG. 5 is finished up. As described above, the super-junction structure may well be formed in such a way that, after the device portion has been formed on the N type substrate 10 earlier, the trench 11 is formed in the N type substrate 10 , followed by the formations of the P type epitaxial layer 12 and the oxide film 13 . Fifth Embodiment In this embodiment, only parts different from the parts of the foregoing embodiments will be described. This embodiment features that a low-concentration N− type substrate or an intrinsic semiconductor substrate is employed beforehand. FIG. 8 is a schematic configurational view of a semiconductor device according to this embodiment. As shown in the figure, an N− type layer 15 (corresponding to a substrate of first conductivity type) is formed on an N+ type layer 1 . The N− type layer 15 is arranged also at the outer edge part of the semiconductor device, and it fulfills the function of ensuring the withstand voltage of the terminal end part of a chip. Besides, a plurality of trenches 11 are formed in the N− type layer 15 , N type layers 16 are formed on the wall surfaces of the trenches 11 , and P type layers 17 are formed so as to fill up the N type layers 16 within the trenches 11 . That is, the N type layers 16 and the P type layers 17 are repeatedly arranged, whereby a super-junction structure is configured. Besides, a device portion is formed at the front surface layer parts of the N− type layer 15 , N type layers 16 and P type layers 17 . Concretely, a P type channel layer 4 is formed at the front surface layer parts of the N− type layer 15 , N type layers 16 and P type layers 17 , and an N+ type source layer 5 is formed at the front surface layer part of the P type channel layer 4 . In addition, a trench 7 reaching the N type layers 16 and the N− type layer 15 is formed penetrating through the N+ type source layer 5 and the P type channel layer 4 , and a gate insulating film 8 and a gate layer 9 are successively formed on the inner wall surface of the trench 7 , whereby a trench gate structure which consists of the trench 7 , gate insulating film 8 and gate layer 9 is configured. Further, a P+ type layer 6 is formed on that part of the P type channel layer 4 which is formed on the P type layer 17 . By the way, electrodes such as a gate electrode and a source electrode, wiring lines, an insulating film, etc. are formed on the trench gate structure in the same manner as in the foregoing embodiments. Besides, the N− type layer 15 is formed with a drain electrode not shown, so as to lie in touch with this N− type layer 15 . The above is the whole configuration of the semiconductor device according to this embodiment. Next, a method for manufacturing the semiconductor device will be described with reference to the drawings. FIGS. 9A to 9F are views showing manufacturing steps for the semiconductor device shown in FIG. 8 . At the step shown in FIG. 9A , a low-concentration N− type substrate 18 is prepared. More specifically, the low-concentration N− type substrate 18 is a silicon substrate which is doped with As, Sb or P as an impurity at a concentration of at most 1×10 15 cm −3 . Incidentally, an intrinsic semiconductor substrate may well be employed. Besides, at the step shown in FIG. 9B , trenches 11 are formed in the same way as at the step shown in FIG. 2B . At the step shown in FIG. 9C , the side surfaces and bottom parts of the trenches 11 are doped with phosphine, arsine or antimony by vapor phase diffusion or ion implantation, thereby to form an N type layer 16 . Further, a CVD equipment is prepared, and the N− type substrate 18 formed with the N type layer 16 is set in the CVD equipment. Besides, a dopant gas of diborane, and HCL gas for suppressing an epitaxial growth at the upper parts of the trenches 11 , are caused to flow through a growth gas of silane, dichlorosilane or trichlorosilane, whereby a P type epitaxial layer 12 is buried in the N type layer 16 . At the step shown in FIG. 9D , the front surface side of the N− type substrate 18 is flattened in the same way as at the step shown in FIG. 2D . Thus, the repeated parts of P type regions (the P type epitaxial layer 12 ) and N type regions (the N type layer 16 ) are denuded on the front surface side of the N− type substrate 18 . At the step shown in FIG. 9E , a device portion is formed by the same method as at the step shown in FIG. 2E . When the device portion has been thus formed, the P type epitaxial layers 12 within the trenches 11 are configured as the P type layers 17 shown in FIG. 8 . At the step shown in FIG. 9F , an N+ type layer 1 is formed in the same way as at the step shown in FIG. 2F . On this occasion, the N type layers 16 formed at the bottom surfaces of the trenches 11 are also made the N+ type layer 1 . Thereafter, the electrodes etc. of the device portion are formed in the same manner as in the foregoing embodiments, whereby the semiconductor device shown in FIG. 8 is finished up. As described above, this embodiment features that, in consideration of the withstand voltage of the terminal end part of the semiconductor device configured as a chip, the semiconductor device is manufactured by employing the low-concentration N− type substrate 18 (or an intrinsic semiconductor substrate) beforehand. Besides, the trenches 11 are formed in the N− type substrate 18 , and the super-junction structure is configured within the trenches 11 . Thus, in manufacturing the semiconductor device, the substrate need not be formed with a layer to become part of the super-junction structure, as an epitaxial layer, and it is possible to diminish the number of manufacturing steps and to curtail the manufacturing cost of the semiconductor device. Besides, since the N type layer 16 is formed on the side surfaces and bottom parts of the trenches 11 by the vapor phase diffusion or the ion implantation, the width of the N type layer 16 can be made small, and the ON-resistance of the device portion can be lowered. Further, in this embodiment, the low-concentration N− type substrate 18 is employed beforehand, and hence, the chip-like semiconductor device in which the withstand voltage of the terminal end part is considered can be manufactured. Sixth Embodiment In this embodiment, only parts different from the parts of the foregoing embodiments will be described. This embodiment features that the third embodiment and the fifth embodiment are combined. FIG. 10 is a schematic sectional view of a semiconductor device according to this embodiment. As shown in the figure, in this embodiment, N type layers 16 are formed on the wall surfaces of trenches 11 . In addition, P type layers 17 are formed on the wall surfaces of the N type layers 16 , and oxide films 13 are formed within the P type layers 17 . Next, a method for manufacturing the semiconductor device will be described with reference to the drawings. FIGS. 11A to 11D are views showing manufacturing steps for the semiconductor device shown in FIG. 10 . First, the steps shown in FIGS. 9A and 9B are performed, thereby to prepare an N− type substrate 18 formed with trenches 11 . At the step shown in FIG. 11A , the side surfaces and bottom parts of the trenches 11 are doped with phosphine, arsine or antimony by vapor phase diffusion or ion implantation, thereby to form an N type layer 16 . Besides, a CVD equipment is prepared, and the N− type substrate 18 formed with the N type layer 16 is set in the CVD equipment. In addition, a dopant gas of diborane is caused to flow through a growth gas of silane, dichlorosilane or trichlorosilane, whereby a P type epitaxial layer 12 is formed on the wall surface of the N type layer 16 so that the N type layer 16 may not be completely filled up. Further, oxide films 13 are buried into the P type epitaxial layer 12 by employing the CVD equipment. At the step shown in FIG. 11B , among the N type layer 16 , P type epitaxial layer 12 and oxide films 13 which are formed on the front surface of the N− type substrate 18 , the oxide films 13 are first removed by dry etching, and the P type epitaxial layer 12 and N type layer 16 are further flattened by dry etching or polishing based on CMP. Thus, the repeated parts of P type regions (the P type epitaxial layer 12 ) and N type regions (the N type layer 16 ) are denuded on the front surface of the N− type substrate 18 . At the step shown in FIG. 11C , a device portion is formed in the same way as in FIG. 6C . In addition, the P type epitaxial layers 12 within the trenches 11 are configured as the P type layers 17 shown in FIG. 10 . At the step shown in FIG. 11D , an N+ type layer 1 is formed in the same way as at the step shown in FIG. 9F . Thereafter, electrodes etc. not shown are formed as stated before, whereby the semiconductor device shown in FIG. 10 is finished up. As described before, the P type layers 17 and the oxide films 13 may well be formed within the trenches 11 provided in the N− type substrate 18 . Seventh Embodiment In this embodiment, only parts different from the parts of the foregoing embodiments will be described. This embodiment features that the MOS transistor of N-channel type shown in each of the foregoing embodiments, and a MOS transistor of P-channel type are formed in a single chip. FIG. 12 is a schematic sectional view of a semiconductor device according to this embodiment. As shown in the figure, the semiconductor device is formed with a super-junction structure in which N type layers 2 and P type layers 3 are repeatedly arranged. Besides, the semiconductor device shown in FIG. 12 is formed with the MOS transistor of the N-channel type and the MOS transistor of the P-channel type. In the semiconductor device, in a region where the N-channel type MOS transistor is formed, a trench gate structure is formed in an N type region, and an N+ type layer 1 is formed on the side of a substrate remote from the trench gate structure. Besides, in the semiconductor device, in a region where the P-channel type MOS transistor is formed, a trench gate structure is formed in a P type region, and a P+ type layer 19 (corresponding to a second layer of second conductivity type) is formed on the side of the substrate remote from the trench gate structure. In this embodiment, the N+ type layer 1 and the P+ type layer 19 can be selectively formed on the rear surface side of the substrate by well-known photolithographic processes, etc. By the way, in case of forming the P+ type layer 19 , boron is diffused by ion implantation. As described above, in the semiconductor device having the super-junction structure in which the N type layers 2 and the P type layers 3 are repeatedly arranged, the respective MOS transistors of the N-channel type and the P-channel type can be formed. Other Embodiments In each of the first to sixth embodiments, there has been described the semiconductor device including the MOS transistor of N-channel type as the device portion. However, a semiconductor device including a MOS transistor of P-channel type as a device portion can also be manufactured by forming a trench gate structure in the P type layer 3 . Besides, in each of the first to sixth embodiments, the N type substrate 10 has been employed in manufacturing the semiconductor device, but a semiconductor device may well be manufactured by employing a P type substrate. That is, in each of the first to sixth embodiments, the semiconductor device can have the conductivity types of N and P types replaced with each other. By way of example, in each of the first to fourth embodiments, a P type substrate is prepared instead of the N type substrate 10 , or in each of the fifth and sixth embodiments, a P− type substrate is prepared instead of the N− type substrate 18 , whereupon a semiconductor device is manufactured on the corresponding substrate. In the first embodiment, the semiconductor device shown in FIG. 1 has the structure in which the P type layer 3 and the N type layer 2 are formed on the N+ type layer 1 . However, a quantity in which the N type substrate 10 is cut down at the step shown in FIG. 2F may well be adjusted, thereby to configure a structure in which the N type layer 2 is held between the N+ type layer 1 and the P type layer 3 . In the third embodiment, the semiconductor device shown in FIG. 5 has the structure in which the oxide film 13 is formed between the N+ type layer 1 and the P type layer 3 . However, a quantity in which the N type substrate 10 is cut down at the step shown in FIG. 6D may well be adjusted, thereby to configure a structure in which the P type layer 3 is formed on the N+ type layer 1 . In the third embodiment, the P type epitaxial layer 12 has been formed by the CVD equipment at the step shown in FIG. 6C . However, instead of the formation of the P type epitaxial layer 12 , the side wall of the trench 11 can be subjected to doping by vapor phase diffusion or ion implantation, whereby a P type layer corresponding to the P type epitaxial layer 12 is formed so as to bury the oxide film 13 within the P type layer. Besides, in each of the third and fourth embodiments, the P type layer 3 has been formed by the epitaxial growth on the wall surface of the trench 11 of the N type substrate 10 , but the P type layer 3 may well be formed by vapor phase diffusion or ion implantation from the side wall of the trench 11 . Also in this case, in order to absorb out the impurity ions of the P type layer 3 into the oxide film 13 after the formation of the device portion and to attain the charge balance, the P type layer 3 should preferably be formed in the case of the vapor phase diffusion or the ion implantation so that the impurity concentration of the P type layer 3 formed within the trench 11 may become higher than the impurity concentration of the N type substrate 10 . In each of the fifth and sixth embodiments, a super-junction structure can also be formed in such a way that, in the same manner as in each of the second and fourth embodiments, the N type layer 16 and the P type layer 3 are formed by forming the trench 11 after the device portion has been formed on the N− type substrate 18 earlier. Besides, the N type layer 2 has been formed on the wall surface of the trench 11 of the N− type substrate 18 by the method of the vapor phase diffusion or the ion implantation, but an N type layer 2 may well be formed by epitaxially growing the N type layer 2 within the trench 11 . In the seventh embodiment, there has been described the semiconductor device in which the MOS transistors of N-channel type and P-channel type are formed in the single chip. It is also allowed, however, to employ a configuration in which the semiconductor device is formed with the oxide film 13 shown in, for example, the third embodiment. Besides, in the case where the MOS transistors of the N-channel type and the P-channel type are formed in the single chip, an N type layer 2 may well be included in consideration of the withstand voltage of the terminal end part of the chip as in the fifth or sixth embodiment. In this case, as stated before, the repeated structure is formed by forming the trenches in the N− type substrate 18 , and the MOS transistors of the N-channel type and the P-channel type are respectively formed as in the seventh embodiment. The above disclosure has the following features. According to the first feature, in manufacturing a semiconductor device which has a super-junction structure wherein a region of first conductivity type (for example, N type) (a first layer ( 2 ) of the first conductivity type) and a region of second conductivity type (for example, P type) (a first layer ( 3 ) of the second conductivity type) are repeatedly arranged, a substrate ( 10 ) of the first conductivity type to become the first layer ( 2 ) of the first conductivity type as a drift region at a later step is first prepared, and a trench ( 11 ) is formed on the front surface side of the substrate ( 10 ) of the first conductivity type. In addition, the first layer ( 3 ) of the second conductivity type is formed within the trench ( 11 ). Thus, a region held between the first layers ( 3 ) of the second conductivity type, within the substrate ( 10 ) of the first conductivity type, is used as the first layer ( 2 ) of the first conductivity type, thereby to form a structure in which the first layer ( 2 ) of the first conductivity type and the first layer ( 3 ) of the second conductivity type are repeatedly arranged. Thereafter, the rear surface side of the substrate ( 10 ) of the first conductivity type formed with the repeated structure is thinned, thereby to form a second layer ( 1 ) of the first conductivity type on the rear surface side. In this manner, the substrate ( 10 ) of the first conductivity type to configure the first layer ( 2 ) of the first conductivity type constituting the repeated structure is prepared, and the repeated structure is formed by employing the substrate ( 10 ) of the first conductivity type. Thus, it is possible to omit, for example, the step of preparing a support substrate configured as the second layer ( 1 ) of the first conductivity type and epitaxially growing the first layer ( 2 ) of the first conductivity type for the repeated structure, on the support substrate, and it is possible to relieve a manufacturing process and to curtail a manufacturing cost. Owing to the relief of the manufacturing process, the semiconductor device can be manufactured in a short time. Besides, as stated above, the substrate ( 10 ) of the first conductivity type is employed without employing the base substrate which is configured as the second layer ( 1 ) of the first conductivity type and which has an impurity concentration higher than that of the substrate ( 10 ) of the first conductivity type. Therefore, in forming the first layer ( 3 ) of the second conductivity type within the trench ( 11 ), it is possible to suppress an outward diffusion in which an impurity migrates from the substrate ( 10 ) of the first conductivity type into the first layer ( 3 ) of the second conductivity type, and the impurity concentration of the first layer ( 3 ) of the second conductivity type can be prevented from deviating from a target value. As the second feature, in the case of manufacturing the semiconductor device as stated above, it is possible to manufacture a semiconductor device in which the first layer ( 2 ) of the first conductivity type and the first layer ( 3 ) of the second conductivity type that are drift regions form the repeated structure, and which includes an N-channel type semiconductor element of vertical type that uses the first layer ( 2 ) of the first conductivity type as its drift region, and a P-channel type semiconductor element of vertical type that uses the first layer ( 3 ) of the second conductivity type as its drift region. Even in the case where, in this manner, the single semiconductor device in which the semiconductor elements of N-channel and P-channel are formed is to be manufactured, the semiconductor device can be manufactured by preparing the substrate ( 10 ) of the first conductivity type to become the first layer ( 2 ) of the first conductivity type being the drift region, as stated above. Besides, in preparing the substrate ( 10 ) of the first conductivity type, the impurity concentration of the substrate ( 10 ) of the first conductivity type is measured, and at the step of forming the first layer ( 3 ) of the second conductivity type, the first layer ( 3 ) of the second conductivity type is formed so that the product between the impurity concentration of the substrate ( 10 ) of the first conductivity type measured beforehand and the width of the layer of the first conductivity type (N type) between the first layers ( 3 ) of the second conductivity type may become equal to the product between the width of the first layer ( 3 ) of the second conductivity type between the first layers ( 2 ) of the first conductivity type and the impurity concentration of the first layer ( 3 ) of the second conductivity type, in other words, that a charge balance may be attained. In this manner, the concentration and trench width of the substrate ( 10 ) of the first conductivity type are measured beforehand, and in forming the first layer ( 3 ) of the second conductivity type, this first layer ( 3 ) of the second conductivity type can be formed while the charge balance is being adjusted. Thus, the withstand voltages of the semiconductor elements can be enhanced. Further, in forming the first layer ( 3 ) of the second conductivity type, this first layer ( 3 ) of the second conductivity type can be formed without lowering the temperature of the substrate ( 10 ) of the first conductivity type stepwise. Thus, the outward diffusion of impurity ions from the substrate ( 10 ) of the first conductivity type into the first layer ( 3 ) of the second conductivity type can be prevented from occurring. Besides, after the repeated structure has been formed, the N-channel type semiconductor element of the vertical type can be formed at the front surface layer part of the first layer ( 2 ) of the first conductivity type constituting the repeated structure. To the contrary, after the substrate ( 10 ) of the first conductivity type has been prepared, the N-channel type semiconductor element of the vertical type is formed at the front surface layer part of the substrate ( 10 ) of the first conductivity type, whereupon at the later step of forming the trenches ( 11 ), the trenches ( 11 ) can be formed between the N-channel type semiconductor elements of the vertical type in the substrate ( 10 ) of the first conductivity type. As the third feature, a substrate ( 10 ) of first conductivity type is prepared, and a trench ( 11 ) is formed on the front surface side of the substrate ( 10 ) of the first conductivity type, whereupon a first layer ( 3 ) of second conductivity type is epitaxially grown on the inner wall surface of the trench ( 11 ) to a thickness of, at most, half of the width of the trench ( 11 ). In addition, an oxide film ( 13 ) is formed on the first layer ( 3 ) of the second conductivity type epitaxially grown, and the trench ( 11 ) is filled up with the oxide film ( 13 ), whereby a region held between the first layers ( 3 ) of the second conductivity type, in the substrate ( 10 ) of the first conductivity type, is used as a first layer ( 2 ) of the first conductivity type, and a repeated structure in which the first layer ( 2 ) of the first conductivity type and the first layer ( 3 ) of the second conductivity type are alternately arranged is formed. In this manner, the first layer ( 3 ) of the second conductivity type is epitaxially grown within the trench ( 11 ), whereby the width of the first layer ( 3 ) of the second conductivity type can be made small, and in turn, an ON-resistance in the first layer ( 3 ) of the second conductivity type can be lowered. Besides, as the fourth feature, regarding the third feature, in forming the first layer ( 3 ) of the second conductivity type, the inner wall surface of the trench ( 11 ) provided in the substrate ( 10 ) of the first conductivity type is subjected to vapor phase diffusion or to ion implantation, whereby the wall surface of the trench ( 11 ) is formed into the first layer ( 3 ) of the second conductivity type. In this manner, the first layer ( 3 ) of the second conductivity type is not formed within the trench ( 11 ), but the wall surface of the trench ( 11 ) can be formed as the first layer ( 3 ) of the second conductivity type. In case of forming a semiconductor element, the repeated structure is formed, and the N-channel type semiconductor element of vertical type can be thereafter formed at the front surface layer part of a first layer ( 2 ) of first conductivity type constituting the repeated structure. To the contrary, after a substrate ( 10 ) of the first conductivity type has been prepared, the N-channel type semiconductor element of the vertical type is formed at the front surface layer part of the substrate ( 10 ) of the first conductivity type, whereupon a trench ( 11 ) can be formed between the N-channel type semiconductor elements of the vertical type. Besides, in preparing the substrate ( 10 ) of the first conductivity type, the impurity concentration of the substrate ( 10 ) of the first conductivity type is measured beforehand. In addition, after the N-channel type semiconductor element of the vertical type has been formed on the substrate ( 10 ) of the first conductivity type, the withstand voltage of the N-channel type semiconductor element of the vertical type is measured. Thereafter, in a case where the measured withstand voltage is lower than a reference value, the substrate ( 10 ) of the first conductivity type is heat-treated so that the product between the impurity concentration of the substrate ( 10 ) of the first conductivity type and the width of the first layer ( 2 ) of the first conductivity type between first layers ( 3 ) of second conductivity type may become equal to the product between the width of the first layer ( 3 ) of the second conductivity type between the first layers ( 2 ) of the first conductivity type and the impurity concentration of the first layer ( 3 ) of the second conductivity type. In this way, impurity ions contained in the first layer ( 3 ) of the second conductivity type can be absorbed out from this first layer ( 3 ) of the second conductivity type into an oxide film ( 13 ). Thus, the charge balance between the first layer ( 2 ) of the first conductivity type and the first layer ( 3 ) of the second conductivity type can be attained, and the withstand voltage of the semiconductor element can be enhanced. In the case of absorbing out the impurity ions of the first layer ( 3 ) of the second conductivity type into the oxide film ( 13 ) as stated above, in forming the first layer ( 3 ) of the second conductivity type, this first layer ( 3 ) of the second conductivity type should preferably be formed so that the impurity concentration of the first layer ( 3 ) of the second conductivity type may become higher than the impurity concentration of the substrate ( 10 ) of the first conductivity type. That is, in the case where the impurity ions of the first layer ( 3 ) of the second conductivity type are absorbed out into the oxide film ( 13 ) by heat-treating the substrate ( 10 ) of the first conductivity type, thereby to attain the charge balance between the first layer ( 2 ) of the first conductivity type and the first layer ( 3 ) of the second conductivity type, the impurity ions are swept out from the first layer ( 3 ) of the second conductivity type. Therefore, the impurity concentration of the first layer ( 3 ) of the second conductivity type is set higher beforehand, whereby the adjustment of the charge balance in the case of heat-treating the substrate ( 10 ) of the first conductivity type can be performed with ease. Besides, in the case of adjusting the charge balance, in forming the first layer ( 3 ) of the second conductivity type, this first layer ( 3 ) of the second conductivity type should preferably be formed so that the product between the width of the first layer ( 3 ) of the second conductivity type between the first layers ( 2 ) of the first conductivity type and the impurity concentration of the first layer ( 3 ) of the second conductivity type may become larger than the product between the impurity concentration of the substrate ( 10 ) of the first conductivity type and the width of the first layer ( 2 ) of the first conductivity type between the first layers ( 3 ) of the second conductivity type. The first layer ( 3 ) of the second conductivity type is formed so as to satisfy such a condition, whereby the adjustment of the charge balance in the case of heat-treating the substrate ( 10 ) of the first conductivity type can be easily performed as in the above. In preparing the substrate ( 10 ) of the first conductivity type, a substrate which is doped with phosphorus, arsenic or antimony as an impurity should preferably be prepared as the substrate ( 10 ) of the first conductivity type. Besides, in preparing the substrate ( 10 ) of the first conductivity type, a substrate whose impurity concentration is at least 1×10 15 cm −3 and at most 1×10 18 cm −3 should preferably be prepared as the substrate ( 10 ) of the first conductivity type. That is, it is desirable to set the lower limit of a doping quantity at 1×10 15 cm −3 for the purpose of obtaining the substrate doped with the impurity, and to set the upper limit of the doping quantity at 1×10 18 cm −3 for the purpose of avoiding a situation where any depletion layer is not formed. As the fifth feature, a substrate ( 18 ) of first conductivity type which is lower in impurity concentration than a first layer ( 2 ) of the first conductivity type is prepared, and trenches ( 11 ) are formed on the front surface side of the substrate ( 18 ) of the first conductivity type. In addition, inner wall surfaces of the trenches ( 11 ) are subjected to vapor phase diffusion or ion implantation, whereby the wall surfaces of the trenches ( 11 ) are formed into the first layer ( 2 ) of the first conductivity type. Thereafter, a first layer ( 3 ) of second conductivity type is formed on the first layer ( 2 ) of the first conductivity type, thereby to form a structure in which the first layer ( 2 ) of the first conductivity type and the first layer ( 3 ) of the second conductivity type are repeatedly arranged. The rear surface side of the substrate ( 18 ) of the first conductivity type formed with the repeated structure is thinned, thereby to form a second layer ( 1 ) of the first conductivity type on the rear surface side. In this manner, in manufacturing a semiconductor device, the substrate ( 18 ) of the first conductivity type is first prepared. Thus, as stated before, epitaxial films for the repeated structure need not be formed beforehand. Besides, owing to the use of the substrate ( 18 ) of the first conductivity type, the semiconductor device in which the terminal end part of a chip is considered can be manufactured. As the sixth feature, regarding the fifth feature, the first layer ( 2 ) of the first conductivity type is epitaxially grown on the inner wall surfaces of the trenches ( 11 ) formed on the front surface side of the substrate ( 18 ) of the first conductivity type, and the first layer ( 3 ) of the second conductivity type is epitaxially grown on the first layer ( 2 ) of the first conductivity type. In this manner, the first layer ( 2 ) of the first conductivity type and the first layer ( 3 ) of the second conductivity type may well be respectively formed by the epitaxial growths. Thus, the widths of the first layer ( 2 ) of the first conductivity type and the first layer ( 3 ) of the second conductivity type can be made small, and ion resistances in the respective layers can be lowered. As the seventh feature, regarding the fifth feature, oxide films ( 13 ) are formed on the first layer ( 3 ) of the second conductivity type, thereby to fill up the trenches ( 11 ) with the oxide films ( 13 ). In this manner, the structure in which the trenches ( 11 ) are filled up with the oxide films ( 13 ) can also be formed. In the case of manufacturing the semiconductor device by employing the substrate ( 18 ) of the first conductivity type as stated above, the substrate ( 18 ) of the first conductivity type is prepared, and N-channel type semiconductor elements of vertical type are thereafter formed at the front surface layer part of the substrate ( 18 ) of the first conductivity type, whereupon the trench ( 11 ) can be formed between the N-channel type semiconductor elements of the vertical type, in the substrate ( 18 ) of the first conductivity type. In the case of manufacturing the semiconductor device by employing the substrate ( 18 ) of the first conductivity type, before a second layer ( 1 ) of the first conductivity type is formed on the rear surface side of the substrate ( 18 ), the N-channel type semiconductor element of the vertical type can also be formed at the front surface layer parts of the first layer ( 2 ) of the first conductivity type constituting the repeated structure and a third layer ( 15 ) of the first conductivity type held between the first layers ( 2 ) of the first conductivity type. Incidentally, the bracketed numerals of the various means indicate corresponding relations with concrete means which will be stated in embodiments to be described later. While the invention has been described with reference to preferred embodiments thereof, it is to be understood that the invention is not limited to the preferred embodiments and constructions. The invention is intended to cover various modification and equivalent arrangements. In addition, while the various combinations and configurations, which are preferred, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the invention.

A manufacturing method of a semiconductor device includes: forming multiple trenches on a semiconductor substrate; forming a second conductive type semiconductor film in each trench to provide a first column with the substrate between two trenches and a second column with the second conductive type semiconductor film in the trench, the first and second columns alternately repeated along with a predetermined direction; thinning a second side of the substrate; and increasing an impurity concentration in a thinned second side so that a first conductive type layer is provided. The impurity concentration of the first conductive type layer is higher than the first column. The first column provides a drift layer so that a vertical type first-conductive-type channel transistor is formed.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a magnetic resonance imaging apparatus and a magnetic resonance imaging method which excite nuclear spin of an object magnetically with a RF signal having the Larmor frequency and reconstruct an image based on a magnetic resonance signal generated due to the excitation, and more particularly, to a magnetic resonance imaging apparatus and a magnetic resonance imaging method, which reconstruct an image with suppression or excitation of a magnetic resonance signal from a specific part, such as fat-saturation. [0003] 2. Description of the Related Art [0004] Magnetic Resonance Imaging (MRI) is an imaging method which excite nuclear spin of an object set in a static magnetic field with a radio frequency (RF) signal having the Larmor frequency magnetically and reconstruct an image based on a magnetic resonance (MR) signal generated due to the excitation. [0005] In the field of magnetic resonance imaging, MRA (magnetic resonance angiography) is known as a method for obtaining an image of the blood flow at a desired portion, such as the head, lung field, or stomach. The MRA includes enhanced MRA and un-enhanced MRA. The enhanced MRA is an imaging method with a contrast medium injected to an object. The un-enhanced MRA is an imaging method without a contrast medium. In any MRA, importantly, in order to obtain the image of the blood flow, an MR signal from a fat is suppressed and an MR signal from water, serving as a component of the blood flow, is excited, thereby sufficiently obtaining the contrast between a blood flow region and a parenchymal region other than the blood flow region. [0006] Conventionally, a fat-water separation method is used. According to the fat-water separation method, an MR signal (fat signal) from the fat is suppressed by using the difference (chemical shift) in resonant frequencies between protons of fat and water. The fat-water separation method includes a pre-pulse method and a water excitation method. The pre-pulse method has been put into practical use. According to the pre-pulse method, a fat saturation pulse for suppressing a fat signal is applied to the object, as a pre-pulse prior to imaging a blood flow. This pre-pulse selectively excites only the fat depending on frequencies so that protons of the fat are saturated. Subsequently, an imaging of blood flow starts. According to the water excitation method, a water excitation pulse is applied, as an excitation pulse. The improvement in this water excitation pulse enables the excitation of only the MR signal (water signal) from the water without generating the fat signal. [0007] Further, according to the fat-water separation method using the pre-pulse method, in order to prevent a trouble of the reduction in water signal due to the small difference in resonant frequencies between protons of a fat and water, an improvement in a frequency band of a fat saturation pulse to suppress the reduction in a water signal is suggested (see, for example, JP-A-2002-306447). [0008] When a frequency shifted from the resonant frequency of protons of water by 500 Hz is selectively excited by an RF pulse, an MR signal level from protons of a high polymer, serving as a fat component, and an MR signal level from protons of water are reduced respectively. Advantageously, an image with the contrast depending on the rate of high polymers is obtained. In this case, an MR signal level at the fat region is excessively reduced, as compared with an MR signal level at the blood flow region. [0009] In order to obtain the above-mentioned MT (magnetization transfer) advantages, a technology for applying an RF pulse, so-called MTC (magnetization transfer contrast) pulse, as a pre-pulse to the object prior to imaging, is proposed. This technology is applied to an MRA with the extraction of a little blood vessel (see, for example, JP-A-H06-319715). [0010] Further, based on three dimensional (3D) image data obtained with various improving technologies of contrast for applying a fat saturation pulse, a water excitation pulse, and an MTC pulse, imaging processing such as MIP (maximum intensity projection) processing generates three dimensional image data for diagnosis, such as an MIP image. [0011] A fat saturation or a water excitation under the conventional MRA uses the difference (chemical shift) in resonant frequencies between protons of a fat and water. Therefore, when a region as an imaging target includes an uneven magnetic field, there is a problem that a fat signal cannot be properly suppressed or a water signal cannot be properly excited. In particular, in the case of MRA of the head of the object, the region near a curve portion of a blood vessel passing through the bone portion ranging from a carotid pyramidal portion to a syphone partly includes uneven magnetic field. Therefore, the fat signal is not preferably suppressed and the water signal is not preferably excited. The MR signal from the water component is lost and an MRA image with the lost blood flow region may be generated. [0012] Currently, the improvement in sequence waveform, serving as an imaging condition, cannot solve the problem regarding as the loss of the blood flow region on the MRA image obtained in a region having an uneven magnetic field. [0013] Then, when the uneven magnetic field is not ignored and a fat signal cannot be preferably suppressed or a water signal cannot be preferably excited, the image is obtained without the fat saturation or the water excitation. Then, the image data as an imaging result is subjected to imaging processing, such as region processing, thereby generating image data suitable for diagnosis. [0014] For example, in the case of the MRA of the head for generating a blood flow image of the head, a fat region near a scalp does not enable the extraction of blood vessel. Therefore, the fat region needs to be removed from the image data. Then, for the image data obtained by the imaging without the fat saturation of head, an inner region of the scalp is set as a region of interest (ROI), thereby removing the peripheral fat region including the scalp from the image data. Then, only the image data at the inner region of the scalp is subjected to specific MIP processing, such as Partial-MIP processing, thereby generating the image data suitable to the diagnosis. [0015] As a consequence, a troublesome operation including the setting of an ROI and the removal of image data at the fat region is needed. In particular, in Whole Brain MRA, the operation including the setting of an ROI and the removal of image data at the fat region is more complicated and further impossible. [0016] That is, the conventional technologies of the fat saturation and water excitation cannot be applied to a portion, such as a curve portion with an uneven magnetic field particularly, and need specific image processing, such as Partial MIP for generating an image data for diagnosis. In other words, in the case of obtaining an MRA image at a portion such as a curve portion, the conventional technologies of the fat saturation and water excitation have a problem that it is not possible to obtain the original merit of the conventional technologies of the fat saturation and water excitation, that is, a merit for obtaining an MRA image with a small loss of the blood vessel region at a wide area without specific imaging processing. SUMMARY OF THE INVENTION [0017] The present invention has been made in light of the conventional situations, and it is an object of the present invention to provide a magnetic resonance imaging apparatus and a magnetic resonance imaging method which make it possible to obtain a MRA image having few deficits of a blood vessel without performing a special MIP processing, such as Partial MIP processing, due to a contrast improvement technology based on an imaging condition, such as fat-saturation and water excitation, even if it is the case where a MRA image in part which is easy to become uneven a magnetic field, such as a flexion part, is to be obtained. [0018] The present invention provides a magnetic resonance imaging apparatus comprising: an imaging condition setting unit configured to set a first imaging condition and a second imaging condition at least; a gradient coil configured to impress gradient magnetic fields to an object in a static magnetic field in accordance with the first imaging condition and the second imaging condition; a radio frequency coil configured to transmit radio frequency signals to the object in accordance with the first imaging condition and the second imaging condition; a data acquisition unit configured to acquire first magnetic resonance signal data corresponding to the first imaging condition and second magnetic resonance signal data corresponding to the second imaging condition from the object; an image reconstructing unit configured to reconstruct first three dimensional image data regarding the object in accordance with the first magnetic resonance signal data and second three dimensional image data regarding the object in accordance with the second magnetic resonance signal data; and an image data generating unit configured to combine the first three dimensional image data and the second three dimensional image data to generate third three dimensional image data, in an aspect to achieve the object. [0019] The present invention also provides a magnetic resonance imaging apparatus comprising: means for setting a first imaging condition and a second imaging condition at least; means for impressing gradient magnetic fields to an object in a static magnetic field in accordance with the first imaging condition and the second imaging condition; means for transmitting radio frequency signals to the object in accordance with the first imaging condition and the second imaging condition; means for acquiring first magnetic resonance signal data corresponding to the first imaging condition and second magnetic resonance signal data corresponding to the second imaging condition from the object; means for reconstructing first three dimensional image data regarding the object in accordance with the first magnetic resonance signal data and second three dimensional image data regarding the object in accordance with the second magnetic resonance signal data; and means for combining the first three dimensional image data and the second three dimensional image data to generate third three dimensional image data, in an aspect to achieve the object. [0020] The present invention also provides a magnetic resonance imaging method comprising steps of: setting a first imaging condition and a second imaging condition at least; impressing gradient magnetic fields to an object in a static magnetic field in accordance with the first imaging condition and the second imaging condition; transmitting radio frequency signals to the object in accordance with the first imaging condition and the second imaging condition; acquiring first magnetic resonance signal data corresponding to the first imaging condition and second magnetic resonance signal data corresponding to the second imaging condition from the object; reconstructing first three dimensional image data regarding the object in accordance with the first magnetic resonance signal data and second three dimensional image data regarding the object in accordance with the second magnetic resonance signal data; and combining the first three dimensional image data and the second three dimensional image data to generate third three dimensional image data, in an aspect to achieve the object. [0021] The magnetic resonance imaging apparatus and the magnetic resonance imaging method as described above make it possible to obtain a MRA image having few deficits of a blood vessel without performing a special MIP processing, such as Partial MIP processing, due to a contrast improvement technology based on an imaging condition, such as fat-saturation and water excitation, even if it is the case where a MRA image in part which is easy to become uneven a magnetic field, such as a flexion part, is to be obtained. BRIEF DESCRIPTION OF THE DRAWINGS [0022] In the accompanying drawings: [0023] FIG. 1 is a block diagram showing a magnetic resonance imaging apparatus according to a first embodiment of the present invention; [0024] FIG. 2 is a functional block diagram of the computer in the magnetic resonance imaging apparatus shown in FIG. 1 ; [0025] FIG. 3 is a flowchart showing an example of flow for imaging a MRA image according to the head of the object with the magnetic resonance imaging apparatus shown in FIG. 1 ; [0026] FIG. 4 is a diagram showing the position of the carotid syphone of the head determined as an example of a replacement area on three dimensional image data in the magnetic resonance imaging apparatus shown in FIG. 1 ; [0027] FIG. 5 is a diagram showing an example of a sequence used in a case where a scan is performed with switching the existence of the fat-water separation with a pre-pulse method while fundamental imaging conditions are to be identity in the magnetic resonance imaging apparatus shown in FIG. 1 ; [0028] FIG. 6 is a diagram showing an example of a sequence used in a case where a scan is performed with switching the existence of the fat-water separation with a water-excitation method while fundamental imaging conditions are not to be identity in the magnetic resonance imaging apparatus shown in FIG. 1 ; [0029] FIG. 7 is a diagram showing an example of slabs which is to be imaging objects by the magnetic resonance imaging apparatus shown in FIG. 1 ; [0030] FIG. 8 is a diagram showing an imaging order for the slabs shown in FIG. 7 and the existence of the fat-water separation; [0031] FIG. 9 is a diagram explaining a method for replacing three dimensional image data in the magnetic resonance imaging apparatus shown in FIG. 1 ; [0032] FIG. 10 is a diagram explaining an example of weighting processing performed when single three dimensional image data is generated from the three dimensional image data obtained respectively with switching the existence of the fat-water separation in the magnetic resonance imaging apparatus shown in FIG. 1 ; [0033] FIG. 11 is a diagram showing an example of a sequence for describing a magnetic resonance imaging apparatus according to a second embodiment of the present invention; and [0034] FIG. 12 is a diagram which compares the spectrum of the proton contained in water and that in a high polymer for explaining a MT effect obtained due to a MTC pulse on the sequence shown as A) in FIG. 11 . DESCRIPTION OF THE PREFERRED EMBODIMENTS [0035] A magnetic resonance imaging apparatus and a magnetic resonance imaging method according to embodiments of the present invention will be described with reference to the accompanying drawings. [0036] FIG. 1 is a block diagram showing a magnetic resonance imaging apparatus according to a first embodiment of the present invention. [0037] A magnetic resonance imaging apparatus 20 includes a static field magnet 21 for generating a static magnetic field, a shim coil 22 arranged inside the static field magnet 21 which is cylinder-shaped, a gradient coil unit 23 and a RF coil 24 . The static field magnet 21 , the shim coil 22 , the gradient coil unit 23 and the RF coil 24 are built in a gantry (not shown). [0038] The magnetic resonance imaging apparatus 20 also includes a control system 25 . The control system 25 includes a static magnetic field power supply 26 , a gradient power supply 27 , a shim coil power supply 28 , a transmitter 29 , a receiver 30 , a sequence controller 31 and a computer 32 . The gradient power supply 27 of the control system 25 includes an X-axis gradient power supply 27 x , a Y-axis gradient power supply 27 y and a Z-axis gradient power supply 27 z . The computer 32 includes an input device 33 , a monitor 34 , a operation unit 35 and a storage unit 36 . [0039] The static field magnet 21 communicates with the static magnetic field power supply 26 . The static magnetic field power supply 26 supplies electric current to the static field magnet 21 to get the function to generate a static magnetic field in a imaging region. The static field magnet 21 includes a superconductivity coil in many cases. The static field magnet 21 gets current from the static magnetic field power supply 26 which communicates with the static field magnet 21 at excitation. However, once excitation has been made, the static field magnet 21 is usually isolated from the static magnetic field power supply 26 . The static field magnet 21 may include a permanent magnet which makes the static magnetic field power supply 26 unnecessary. [0040] The static field magnet 21 has the cylinder-shaped shim coil 22 coaxially inside itself. The shim coil 22 communicates with the shim coil power supply 28 . The shim coil power supply 28 supplies current to the shim coil 22 so that the static magnetic field becomes uniform. [0041] The gradient coil unit 23 includes an X-axis gradient coil unit 23 x , a Y-axis gradient coil unit 23 y and a Z-axis gradient coil unit 23 z . Each of the X-axis gradient coil unit 23 x , the Y-axis gradient coil unit 23 y and the Z-axis gradient coil unit 23 z which is cylinder-shaped is arranged inside the static field magnet 21 . The gradient coil unit 23 has also a bed 37 in the area formed inside it which is an imaging area. The bed 37 supports an object P. Around the bed 37 or the object P, the RF coil 24 may be arranged instead of being built in the gantry. [0042] The gradient coil unit 23 communicates with the gradient power supply 27 . The X-axis gradient coil unit 23 x , the Y-axis gradient coil unit 23 y and the Z-axis gradient coil unit 23 z of the gradient coil unit 23 communicate with the X-axis gradient power supply 27 x , the Y-axis gradient power supply 27 y and the Z-axis gradient power supply 27 z of the gradient power supply 27 respectively. [0043] The X-axis gradient power supply 27 x , the Y-axis gradient power supply 27 y and the Z-axis gradient power supply 27 z supply currents to the X-axis gradient coil unit 23 x , the Y-axis gradient coil unit 23 y and the Z-axis gradient coil unit 23 z respectively so as to generate gradient magnetic fields Gx, Gy and Gz in the X, Y and Z directions in the imaging area. [0044] The RF coil 24 communicates with the transmitter 29 and the receiver 30 . The RF coil 24 has a function to transmit a RF signal given from the transmitter 29 to the object P and receive a MR signal generated due to an nuclear spin inside the object P which is excited by the RF signal to give to the receiver 30 . [0045] The sequence controller 31 of the control system 25 communicates with the gradient power supply 27 , the transmitter 29 and the receiver 30 . The sequence controller 31 has a function to storage sequence information describing control information needed in order to make the gradient power supply 27 , the transmitter 29 and the receiver 30 drive and generate gradient magnetic fields Gx, Gy and Gz in the X, Y and Z directions and a RF signal by driving the gradient power supply 27 , the transmitter 29 and the receiver 30 according to a predetermined sequence stored. The control information above-described includes motion control information, such as intensity, impression period and impression timing of the pulse electric current which should be impressed to the gradient power supply 27 [0046] The sequence controller 31 is also configured to give raw data to the computer 32 . The raw data is complex number data obtained through the detection of a MR signal and A/D conversion to the MR signal detected in the receiver 30 . [0047] The transmitter 29 has a function to give a RF signal to the RF coil 24 in accordance with control information provided from the sequence controller 31 . The receiver 30 has a function to generate raw data which is digitized complex number data by detecting a MR signal given from the RF coil 24 and performing predetermined signal processing and A/D converting to the MR signal detected. The receiver 30 also has a function to give the generated raw data to the sequence controller 31 . [0048] In the example of this embodiment, the elements, i.e., the static field magnet 21 the shim coil 22 the gradient coil unit 23 , the RF coil 24 and the control system 25 , give a function as a raw data acquisition unit to the magnetic resonance imaging apparatus 20 , the raw data acquisition unit impressing a gradient magnetic field and transmitting a RF signal to the object P in a static magnetic field in accordance with imaging condition determined as a sequence and generating raw data by receiving a MR signal produced with a nuclear magnetic resonance of a nucleus due to a RF signal in the object P and digitizing the received MR signal. [0049] The computer 32 gets various functions by the operation unit 35 executing some programs stored in the storage unit 36 of the computer 32 . The computer 32 may include some specific circuits instead of using some of the programs. [0050] FIG. 2 is a functional block diagram of the computer 32 in the magnetic resonance imaging apparatus 20 shown in FIG. 1 . [0051] The computer 32 functions as a sequence controller control unit 40 , an image reconstructing unit 41 , a raw data database 42 , an image data database 43 , an imaging condition setting unit 44 , a combination area setting unit 45 , an image data editing unit 46 , an edited image referring unit 47 and a projection image generating unit 48 . [0052] The sequence controller control unit 40 has a function for controlling the driving of the sequence controller 31 by giving predetermined sequence information to the sequence controller 31 based on information from the input device 33 or another element. In particular, the sequence controller control unit 40 enables the scanning operation with switching the existence of fat-water separation by giving a sequence for fat-water separation in addition to a normal sequence without the fat-water separation to the sequence controller 31 at an arbitrary timing. [0053] Incidentally, the fat-water separation method includes a pre-pulse method and a water excitation method. According to the pre-pulse method, prior to imaging the blood flow, a fat saturation pulse for saturating a fat signal is applied to an object, as a pre-pulse, only the fat is selectively excited depending on the frequency, protons of the fat are saturated, and the imaging of blood flow thereafter starts. According to the water excitation method, a water excitation pulse is applied, as an excitation pulse, and only an MR signal (water signal) from water is excited without generating a fat signal. Any of the above-mentioned fat-water separation methods may be used. [0054] Further, the sequence controller control unit 40 has a function for receiving raw data from the sequence controller 31 and arranging the raw data to k space (Fourier space) formed in the raw data database 42 . [0055] Therefore, the raw data database 42 stores the raw data generated by the receiver 30 , and the raw data is arranged to the k space formed in the raw data database 42 . [0056] The image reconstructing unit 41 has a function for capturing the raw data from the raw data database 42 , performing predetermined image reconstruction processing, such as three dimensional (3D) Fourier transform processing, reconstructing three dimensional image data of the object P, and writing the image data to the image data database 43 . Incidentally, intermediate data, such as two dimensional (2D) image data, may be temporarily generated by processing, such as two dimensional Fourier transform processing, and thereafter the three dimensional image data may be reconstructed. [0057] Therefore, the image data database 43 stores the three dimensional image data of the object P. In particular, in the case of executing the scanning operation with switching the existence of the fat-water separation (including the fat saturation and the water excitation), the image data database 43 stores the three dimensional image data obtained with the fat-water separation and the three dimensional image data without the fat-water separation. [0058] The imaging condition setting unit 44 has a function for generating a sequence for scanning operation with switching the existence of the fat-water separation, and giving the generated sequence to the sequence controller control unit 40 , that is, function for setting an imaging condition. That is, the imaging condition setting unit 44 generates the whole sequence by combining a sequence for executing the scanning operation without the fat-water separation to the sequence for executing the scanning operation with the fat-water separation. In this case, preferably, at an imaging region common to the scanning operation with the fat-water separation and to the scanning operation without the fat-water separation the sequence is formed so that an imaging interval is shorter. [0059] Incidentally, the sequence for executing the scanning operation with the fat-water separation and the sequence for executing the sequence for the scanning operation without the fat-water separation can be independently generated and each of the generated sequences may be individually given to the sequence controller control unit 40 . [0060] The setting of an imaging condition for deciding whether scanning is executed with the fat-water separation or without the fat-water separation refers to a replacement area of the three dimensional image data received from the combination area setting unit 45 , which will be described later. [0061] The image data editing unit 46 has a function for additionally generating three dimensional image data by combining the three dimensional image data with the fat-water separation and the three dimensional image data without the fat-water separation, and a function for giving the generated three dimensional image data to the projection image generating unit 48 and the edited image referring unit 47 . The combining method of the three dimensional image data includes a method for partly replacing the three dimensional image data with the fat-water separation with the three dimensional image data without the fat-water separation, a method contrary to the above-mentioned one and a method for simply adding the three dimensional image data each other. [0062] Further, the image data editing unit 46 has a function for weighting the three dimensional image data with the fat-water separation and the three dimensional image data without the fat-water separation if necessary so as to smooth the additionally-generated three dimensional image. [0063] The combination area setting unit 45 has a function setting a combination area on combining the three dimensional image data with the fat-water separation and the three dimensional image data without the fat-water separation by the image data editing unit 46 . In the case of partly replacing the three dimensional image data with the fat-water separation to the three dimensional image data without the fat-water separation, the replacement area is set based on area designating information, such as designating information of the replacement area, received from the input device 33 . [0064] Further, the combination area setting unit 45 has a function for giving the set combination area, such as the replacement area, to the image data editing unit 46 and the imaging condition setting unit 44 . [0065] Incidentally, the combination area including the replacement area can be automatically performed by various processing, such as threshold processing of the three dimensional image data, or by reference to another image data. Further, in order to designate the combination area, arbitrary image data such as SVR (Shaded volume rendering) image data or MIP image data can be generated, as reference image data, and can be sent to a monitor 34 , thereby easily grasping the entire three dimensional image data spatially. [0066] The edited image referring unit 47 has a function for performing required imaging processing to the three dimensional image data received from the image data editing unit 46 so as to generate image data, giving the generated image data to the monitor 34 , and displaying the image for reference. The image for reference can be an arbitrary image including an MIP image. Then, the edited image referring unit 47 performs processing of the three dimensional image data received from the image data editing unit 46 in accordance with the format of image for reference. [0067] The projection image generating unit 48 has a function for generating MIP image data by performing the MIP processing of the three dimensional image data received from the image data editing unit 46 , and a function for giving the generated MIP image data to the monitor 34 so as to display the MIP image. [0068] With these functions of the computer 32 , the magnetic resonance imaging apparatus 20 has a function for combining image data obtained by executing the scanning operation with the fat-water separation and the scanning operation without the fat-water separation so as to generate additionally image data. Further, the functions of the magnetic resonance imaging apparatus 20 executes the scanning operation without the fat-water separation of the portion having the uneven magnetic field where a proper fat-water separation doesn't work, and executes the scanning operation with the fat-water separation of the portion where a proper fat-water separation works, on imaging of the MRA image of the object P. [0069] The three-dimensional image data obtained respectively are combined each other, thereby obtaining the MRA image with preferable contrast. [0070] Next, the operation of a magnetic resonance imaging apparatus 20 will be described. [0071] FIG. 3 is a flowchart showing an example of flow for imaging a MRA image according to the head of the object P with the magnetic resonance imaging apparatus 20 shown in FIG. 1 . The symbols including S with a number in FIG. 3 indicate each step of the flowchart. [0072] In step S 1 , the operation of the input device 33 designates, as a replacement area of the three dimensional image data, a portion estimated as one having an uneven magnetic field within an imaging range of the object P, e.g., a curve portion of the blood vessel passing through a bone portion ranging from a carotid pyramidal portion to a syphone. That is, the fat is saturated at the portion with the uneven magnetic field and then the advantages of fat-water separation are not preferably obtained. There is a danger that the MR signal from the water component is lost and the MRA image having the lost blood flow region is generated. [0073] Therefore, preferably, at the portion with the uneven magnetic field, e.g., the curve portion, the scanning operation is executed without the fat-water separation and the three dimensional image data is reconstructed. Preferably, at a portion with an even magnetic field, the fat-water separation is executed and the three dimensional image data is reconstructed. [0074] Then, the magnetic resonance imaging apparatus 20 switches the existence of the fat-water separation for each of the imaging portions, that is, each of imaging slices, then, the scanning operation is executed. Therefore, the three dimensional image data reconstructed with the fat-water separation is partly replaced with the three dimensional image data reconstructed without the fat-water separation. In this case, the replacement area is designated in advance. [0075] FIG. 4 is a diagram showing the position of the carotid syphone of the head determined as an example of a replacement area on three dimensional image data in the magnetic resonance imaging apparatus 20 shown in FIG. 1 . [0076] Referring to FIG. 4 , near a carotid syphone 50 A of a head 50 , the magnetic field is uneven. If the fat-water separation is performed, there is a danger that the effect of fat-water separation is not preferably obtained and the MR signal from the water component is lost. Therefore, preferably, near the carotid syphone 50 A of the head 50 , the scanning operation is executed without the fat-water separation and the three dimensional image data is reconstructed. [0077] However, the MR signal from a portion SOB other than the carotid syphone 50 A of the head 50 , particularly, the fat region near the scalp is an obstacle upon extracting the blood vessel. Preferably, the fat-water separation is performed and the three dimensional image data is reconstructed. [0078] The combination area setting unit 45 generates the three dimensional image data serving as image data for reference, such.as MIP image data imaged in advance for reference or tomographic image data of the head 50 . Then, the combination area setting unit 45 gives the generated image data for reference to the monitor 34 . Therefore, a reference image for setting the combined region as shown in FIG. 4 is displayed on the monitor 34 for example. [0079] A user refers to the reference image, such as the MIP image of the head, and can designate a curve portion 51 , e.g., near the carotid syphone 50 A, as the replacement area for the three dimensional image data, by the operation of the input device 33 . The input device 33 gives the replacement area of the three dimensional image data to the combination area setting unit 45 , and the replacement area of the three dimensional image data is set. The combination area setting unit 45 gives the replacement area of the three dimensional image data to the image data editing unit 46 and the imaging condition setting unit 44 . [0080] In step S 2 , the imaging condition setting unit 44 refers to the replacement area of the three dimensional image data received from the combination area setting unit 45 , and generates a sequence obtained by combining the sequence for executing the scanning operation of the entire head of the object P with the fat-water separation and the sequence for executing the scanning operation of only the replacement area of the head without the fat-water separation. [0081] Incidentally, with respect to each imaging condition which does not contribute to the fat-water separation, the imaging condition of the scanning operation with the fat-water separation may be the same as that of the scanning operation without the fat-water separation or may be different therefrom. Each of the imaging conditions which do not contribute to the fat-water separation is properly set depending on the diagnostic target and an imaging method. [0082] FIG. 5 is a diagram showing an example of a sequence used in a case where a scan is performed with switching the existence of the fat-water separation with a pre-pulse method while fundamental imaging conditions are to be identity in the magnetic resonance imaging apparatus 20 shown in FIG. 1 . [0083] Referring to FIG. 5 , a sequence for acquiring the MR signal with the fat saturation under the pre-pulse method is generated for imaging the slices overall the head of the object P. Another sequence for acquiring the MR signal without the fat saturation is generated for imaging the slices including the replacement area of the three dimensional image data. [0084] The sequence with the fat saturation is configured to apply a fat saturation pulse in prior to an excitation pulse as shown in A) of FIG. 5 . An echo time (TE) until acquiring the MR signal (echo) is equal to 3 ms for example. With respect to the slice, referring to FIG. 4 , a number n of slices (s 1 , s 2 , . . . , sn) in the axial direction is plural and each of the slices is properly set with an arbitrary thickness. Therefore, a slice si partly includes the curve portion 51 , e.g., near the carotid syphone 50 A. Then, a gradient magnetic pulse in a slice (SL) direction is set so that all slices of the head are to be scanning targets. [0085] Referring to B) of FIG. 5 , the sequence without the fat saturation is different from the sequence shown A) of FIG. 5 , only in the imaging condition that the fat saturation pulse is deleted. Then, the gradient magnetic pulse in the slice direction is set so that the slice, si including the curve portion 51 , e.g., near the carotid syphone 50 A, is to be a scanning target. Further, parameters of general imaging conditions other than a sequence, such as a field of view (FOV) are set to the same irrespective of the case with the fat saturation and the case without the fat saturation. [0086] That is, FIG. 5 shows an example that the imaging conditions other than the fat saturation pulse contributing to the fat saturation are set to the same, irrespective of the existence of the fat saturation. As mentioned above, the imaging conditions are the same, thereby obtaining the image data under the single imaging condition in the case of combining the three dimensional image data later. Then, the MRA image under the equivalent imaging condition can be obtained. [0087] Incidentally, in case with the fat-water separation under the water excitation method, imaging conditions other than those contributing to the water excitation may be the same. To a contrary, the imaging conditions may be different from each other irrespective of contributing to the water excitation or not so that each of the imaging conditions is to be proper. [0088] FIG. 6 is a diagram showing an example of a sequence used in a case where a scan is performed with switching the existence of the fat-water separation with a water-excitation method while fundamental imaging conditions are not to be identity in the magnetic resonance imaging apparatus 20 shown in FIG. 1 . [0089] Referring to FIG. 6 , a sequence for acquiring the MR signal with the water excitation is generated for imaging the slices overall the head of the object P. Another sequence for acquiring the MR signal with exciting both the water and the fat is generated for imaging the slices including the replacement area of the three dimensional image data. More specifically, the sequence with the water excitation for imaging the overall the head is set so as to apply a water excitation pulse group having a plurality of excitation pulses for water excitation as shown A) of FIG. 6 . An echo time TE 1 until acquiring the MR signal is set to be relatively long. [0090] The sequence without the water excitation is set to have a general excitation pulse for exciting both the water and the fat as shown B) of FIG. 6 . The sequence without the water excitation is also set so as to acquire the MR signal with an echo time TE 2 shorter than the echo time TE 1 of the sequence with the water excitation as shown in A) of FIG. 6 [0091] If the scanning operation is executed with the sequence shown in B) of FIG. 6 , even in the case of the scanning operation of the curve portion 51 , e.g., near the carotid syphone 50 A, the reduction in a signal value of the blood flow due to the turbulence of blood flow at the curve portion 51 is suppressed with the property resistant against the uneven static magnetic field. Thus, the property for extracting the blood flow is improved. [0092] As mentioned above, an imaging condition, such as the echo time, without contributing to the fat-water separation can be properly set. Further, in the case of the fat saturation method, imaging conditions other than the fat saturation pulse may be varied depending on a condition, such as an imaging object. [0093] In addition, whole sequences for imaging the entire head are generated by combining the sequence with the fat-water separation and the sequence without the fat-water separation. The whole sequences for imaging the entire head are formed by arbitrarily aligning the sequences for the slices as shown FIGS. 5 and 6 . Preferably, the whole sequences are generated so as to reduce an imaging interval of the slice common to the scanning operation with the fat-water separation and the scanning operation without the fat-water separation. [0094] FIG. 7 is a diagram showing an example of slabs which is to be imaging objects by the magnetic resonance imaging apparatus 20 shown in FIG. 1 . FIG. 8 is a diagram showing an imaging order for the slabs shown in FIG. 7 and the existence of the fat-water separation. [0095] According to a preferable embodiment, a sequential multi-slab method (also referred to as an MOSTA method) is used for imaging operation while sequentially changing three dimensional slab for imaging target. [0096] Referring to FIG. 7 , when an i-th slab si of n slabs (s 1 , s 2 , . . . , sn) includes the curve portion 51 set as the replacement area of the three dimensional image data, the sequence is generated so as to go on the scanning operation of all n slabs (s 1 , s 2 , . . . , sn) with the fat-water separation in the order of the body axis Z. [0097] Further, the i-th slab si is subjected to the scanning operation without the fat-water separation, in addition to the scanning operation with the fat-water separation. The timing of scanning operation of the i-th slab si without the fat-water separation is set before/after another arbitrary scanning operation. Preferably, the scanning operation of the i-th slab si without the fat-water separation is executed before/after the scanning operation of the i-th slab si with the fat-water separation. [0098] In the case of executing the scanning operation of the i-th slab si without the fat-water separation after the scanning operation of the i-th slab si with the fat-water separation, the scanning operations are executed in the order shown in FIG. 8 . [0099] As mentioned above, the order of scanning operations is set. Thus, the imaging interval of the common slab is reduced and the influence from the motion of the object P can be suppressed. [0100] In the case of a plurality of slabs including the curve portion 51 , similarly, the scanning operations of the slabs without the fat-water separation can be executed before/after the corresponding scanning operations of the slabs with the fat-water separation respectively. Alternatively, the scanning operations may be executed so that the imaging intervals are reduced as much as possible by switching the existence of the fat-water separation by a plurality of slabs. [0101] Then, the imaging condition setting unit 44 gives the generated sequence to the sequence controller control unit 40 . [0102] In step S 3 , the scanning operation is executed by switching the existence of the fat-water separation in accordance with the imaging condition set by the imaging condition setting unit 44 . The three dimensional image data as a result of the scanning operation with the fat-water separation and the three dimensional image data without the fat-water separation are reconstructed respectively. [0103] That is, the object P is set to the bed 37 , and a static magnetic field is generated at an imaging area of the magnet 21 (a superconducting magnet) for static magnetic field excited by the static-magnetic-field power supply 26 . Further, the shim-coil power supply 28 supplies current to the shim coil 22 , thereby uniformizing the static magnetic field generated at the imaging area. [0104] The input device 33 sends an operating command to the sequence controller control unit 40 . The sequence controller control unit 40 supplies the sequence received from the imaging condition setting unit 44 to the sequence controller 31 , thereby controlling the driving operation of the sequence controller 31 . Therefore, the sequence controller 31 drives the gradient power supply 27 , the transmitter 29 , and the receiver 30 in accordance with the sequence received from the sequence controller control unit 40 , thereby generating, at the imaging area having the set object P, an X-axis gradient magnetic field Gx, a Y-axis gradient magnetic field Gy, and a Z-axis gradient magnetic field Gz and further generating RF signals. [0105] In this case, the X-axis gradient magnetic field Gx, Y-axis gradient magnetic field Gy, and Z-axis gradient magnetic field Gz generated by the gradient coils are mainly used as an gradient magnetic field for phase encode (PE), an gradient magnetic field for read out (RO), and an gradient magnetic field for slice (SL), respectively. Consequently, the regularity exists in the rotating directions of nucleus spins within the object P. The gradient magnetic fields for PE and RO individually convert the X coordinate and the Y coordinate into the quantity of phase variety and the quantity of frequency variety of the nucleus spins within the object P. The X coordinate and the Y coordinate are two-dimensional positional information on the slices formed in the Z-axis direction serving as the body axis by the gradient magnetic field for SL. [0106] The transmitter 29 sequentially supplies the RF signals to the RF coil 24 in accordance with the sequence, and the RF coil 24 transmits the RF signals to the object P. [0107] The sequence set by the imaging condition setting unit 44 is set for the purpose of obtaining an MRA image of blood flow at a portion, such as the head. Therefore, the MR signal from the fat is suppressed so as to sufficiently obtain the contrast between the blood flow region and a parenchymal portion other than the blood flow region. Further, all the slabs overall the imaging area are subjected to the fat-water separation exciting the MR signal from the water which is a component of the blood flow. [0108] The fat-water separation method includes the pre-pulse method and the water excitation method as shown in FIGS. 5 and 6 . For example, the pre-pulse method is used and the fat saturation pulse is applied to the object P as a pre-pulse, prior to acquire the MR signal which is used as the original data for generating the blood flow image. Therefore, when the imaging area includes the entire head, prior to acquire the data on slabs of the entire head, the fat saturation pulse selectively excites protons in the fat depending on the frequency, thereby setting the protons to a saturating state. [0109] The protons in the fat enter the saturating state and then the acquisition of data on the MR signal for generating a blood flow image starts. That is, an excitation pulse, serving as a RF signal, is transmitted to the object P, the RF coil 24 receives the MR signals generated by the nuclear magnetic resonance of nucleuses within the object P, and the received signals are sequentially given to the receiver 30 . Since the protons in the fat are in the saturating state, the MR signal from the fat is suppressed. [0110] As mentioned above, the fat is saturated, thereby improving the contrast between the blood flow region and the parenchymal region other than the blood flow region. The static magnetic field is uneven at the curve portion 51 , e.g., near the carotid syphone 50 A, and thus the fat is not preferably saturated. The MR signal from the water which is a component of the blood flow may be lost. [0111] Thus, from the slab including the curve portion 51 , e.g., near the carotid syphone 50 A, the data on the MR signal with the fat saturation pulse and that without the fat saturation pulse are acquired in accordance with the sequence set by the imaging condition setting unit 44 . For example, the data on the MR signal without the fat saturation pulse are acquired subsequently to the acquisition of data on the MR signal with the fat saturation pulse. The interval for acquiring the data on the MR signal from the same slab can be further reduced. Therefore, the amount of positional shift due to the motion of the object P can be reduced. [0112] The RF coil 24 receives the MR signals from the slabs. Then, the receiver 30 receives the MR signals from the RF coil 24 and executes various signal processing including the pre-amplification, conversion of intermediate frequency, phase detection, amplification of low frequency, and filtering, to the received MR signals. Further, the receiver 30 converts an analog MR signal into a digital signal, thereby generating the raw data, serving as the MR signal in the form of the digital data. The receiver 30 supplies the generated raw data to the sequence controller 31 . [0113] The sequence controller 31 supplies the raw data received from the receiver 30 to the sequence controller control unit 40 . The sequence controller control unit 40 arranges the raw data to the k space generated in the raw data database 42 . The raw data database 42 stores the raw data of the slabs of the object P. [0114] Further, the image reconstructing unit 41 captures the raw data from the raw data database 42 and performs predetermined image reconstructing processing, such as three dimensional Fourier transform, thereby reconstructing the three dimensional image data of the object P and writing the data to the image data database 43 . As a result, the image data database 43 stores the three dimensional image data of the entire head obtained with the fat-water separation and the three dimensional image data of the slab including the curve portion 51 , e.g., near the carotid syphone 50 A, obtained without the fat-water separation. [0115] In step S 4 , the image data editing unit 46 reads both the three dimensional image data obtained with the fat-water separation and the three dimensional image data obtained without the fat-water separation from the image data database 43 , and the portion of the replacement area received from the combination area setting unit 45 , of the three dimensional image data imaged with the fat-water separation, is replaced with the three dimensional image data imaged without the fat-water separation, thereby additionally generating the three dimensional image data. [0116] The sequential multi-slice method is described above as an example in the assumption that one slab si includes the carotid syphone 50 A. When a plurality of slabs, e.g., a slab si and a slab si+1 include the carotid syphone 50 A, it is possible to obtain both data with the fat-water separation and those without the fat-water separation according to each of the two slabs. Further, in the imaging operation of “sliding MR imaging” for imaging while sliding the slabs, it is possible to obtain both data with the fat-water separation and those without the fat-water separation according to a part of the slabs. In this case, preferably, the data with the fat-water separation and those without the fat-water separation are subjected to the sliding three dimensional reconstruction respectively. [0117] As mentioned above, the three dimensional image data partly including two types of data is obtained. Hereinbelow, since the concept of slab on acquisition is not necessary, the word of “slice” is used for expression. [0118] FIG. 9 is a diagram explaining a method for replacing three dimensional image data in the magnetic resonance imaging apparatus 20 shown in FIG. 1 . [0119] Referring to FIG. 9 , the image data editing unit 46 reads three dimensional image data D 1 of the entire head obtained with the fat-water separation and three dimensional image data D 2 of the slice including the curve portion 51 , obtained without the fat-water separation, from the image data database 43 . Here, the replacement area is set by the combination area setting unit 45 and, upon generating the MRA image of the entire head, the replacement area corresponds to the curve portion 51 , e.g., near the carotid syphone 50 A. [0120] The image data editing unit 46 replaces the replacement area shown with dotted lines of the three dimensional image data D 1 , corresponding to the entire head, imaged with the fat-water separation by the replacement area (shaded portion) of the three dimensional image data D 2 corresponding to the slice imaged without the fat-water separation, thereby additionally generating three dimensional image data D 3 . [0121] As a consequence, the three dimensional image data D 3 is generated. The three dimensional image data D 3 has the three dimensional image data D 2 obtained without the fat-water separation at the curve portion 51 having a danger that the MR signal from the blood flow is lost due to an insufficient fat-water separation. On the other hand, the three dimensional image data D 3 has the three dimensional image data D 1 obtained with the fat-water separation at the portion other than the curve portion 51 , in which it is needed to saturate fat, in order to extract a blood vessel. The portion other than the curve portion 51 includes the portion near a scalp. [0122] However, if a part of the three dimensional image data D 1 with the fat-water separation is simply replaced by the three dimensional image data D 2 without the fat-water separation, the border of the replacement area (shaded portion) in the newly-generated three dimensional image data D 3 may not be smoothed. [0123] Then, the image data editing unit 46 weights the three dimensional image data D 1 imaged with the fat-water separation and the three dimensional image data D 2 without the fat-water separation if necessary and combines the weighted three dimensional image data D 1 and the weighted three dimensional image data D 2 , thereby smoothing the newly-generated three dimensional image data D 3 . [0124] FIG. 10 is a diagram explaining an example of weighting processing performed when single three dimensional image data is generated from the three dimensional image data obtained respectively with switching the existence of the fat-water separation in the magnetic resonance imaging apparatus 20 shown in FIG. 1 . [0125] Referring to FIG. 10 , the reference symbol D 1 denotes the three dimensional image data on the entire head, imaged with the fat-water separation. As shown by the three dimensional image data D 1 in FIG. 10 , the defect of the fat-water separation suppresses the image of the blood vessel at the replacement area within a dotted line having the uneven magnetic field. On the other hand, the reference symbol D 2 denotes the three dimensional image data to be combined to the replacement area of the three dimensional image data D 1 in FIG. 10 . The three dimensional image data D 2 is of the replacement area, imaged without the fat-water separation. As shown by the three dimensional image data D 2 in FIG. 10 , imaging the replacement area without the fat-water separation allows the image of a blood vessel to be represented satisfactory although the replacement area has the uneven magnetic field. [0126] In order to replace the replacement area of the three dimensional image data D 1 shown in FIG. 10 with the three dimensional image data D 2 , the pixel values of the data D 1 and D 2 are added each other. However, the simple addition may not smooth the image of the border of the replacement area. [0127] Then, in the addition of the three dimensional image data D 1 and D 2 , weight coefficients according to the distance from the border of the replacement area are used for weighting addition. The weight coefficients are shown in graphs on the left to the three dimensional image data D 1 and D 2 in FIG. 10 respectively. The axes in the graphs in FIG. 10 denote values of the weight coefficients which range from 0 to 1, as a standard value respectively. [0128] That is, the weight coefficient K 1 for the three dimensional image data D 1 of the replacement area having the suppressed an image of blood vessels is 1 out of the replacement area. As farther from the border of the replacement area, the weight coefficient K 1 gradually reduces and finally becomes 0. The weight coefficient K 2 for the three dimensional image data D 2 of the replacement area having an image of blood vessels which is preferably drawn is 0 out of the replacement area. As farther from the border of the replacement area, the weight coefficient K 2 gradually increases and finally becomes 1. Then, the three dimensional image data D 1 and D 2 are weighted and added by using the above-set weight coefficients K 1 and K 2 . Thus, the image of blood vessels can preferably be drawn with the smoothness near the border of the replacement area irrespective of the region with even magnetic field. [0129] The image data editing unit 46 gives the generated three dimensional image data to the projection image generating unit 48 and the edited image referring unit 47 . [0130] In step S 5 , the edited image referring unit 47 generates an image data for referring for checking whether or not the replacement area is properly set and the MRA image is preferably generated by using the three dimensional image data received from the image data editing unit 46 as the original data. The image data for referring by which the user can check whether or not the range or position of the replacement area is proper has an arbitrary format or range. The image data for referring can be arbitrary image data, such as SVR image data, as well as MIP image data. For example, the edited image referring unit 47 generates the MIP image data only near the replacement area, as the image data for referring, by using the MIP processing, gives the generated MIP image data to the monitor 34 . [0131] Therefore, the monitor 34 displays the MIP image near the replacement area, and the user can determines whether or not the replacement area is properly set, e.g., whether or not the range or position of the replacement area is shifted. When the replacement area is not properly set, in step S 6 , an instruction for resetting the replacement area is inputted from the input device 33 . Then, in step S 1 , the replacement area starts to be set again. [0132] When the replacement area is properly set and an instruction for resetting the replacement area is not inputted from the input device 33 , in step S 7 , the MIP image data from the three dimensional image data is generated, and is displayed, as an MRA image, on the monitor 34 . That is, the projection image generating unit 48 performs the MIP processing of the three dimensional image data received from the image data editing unit 46 , thereby generating the MIP image data. Further, the generated MIP image data is given to the monitor 34 . Therefore, the monitor 34 displays the MIP image of the blood vessel preferably-drawn as the MRA image irrespective of the region with the even magnetic field. That is, at the curve portion 51 , e.g., near the carotid syphone 50 A, the MRA image without the fat-water separation is set. On the other hand, at another region having the even magnetic field, the MRA image with the advantage of the fat-water separation is set. [0133] When the edited image referring unit 47 generates the MIP image data of the entire head for check operation to be displayed, another MIP image data does not need to be generated. In this case, the edited image referring unit 47 has the shared function of the projection image generating unit 48 . [0134] That is, in the imaging operation of the MRA image, the above-mentioned magnetic resonance imaging apparatus 20 has a function for obtaining both the images with and without the fat-water separation at the area where the fat-water separation is not to be sufficient, replacing the three dimensional image data obtained with the fat-water separation to the three dimensional image data partially having data without the fat-water separation, and performing the MIP processing to the replaced data. [0135] Therefore, even at the curve portion 51 , such as the syphone portion of the head, at which the fat is not conventionally saturated sufficiently, the magnetic resonance imaging apparatus 20 selectively performs the fat-water separation of only the portion with the preferable fat-water separation without the complicated imaging processing, such as Partial MIP. Thus, the magnetic resonance imaging apparatus 20 obtains the wide MRA image with preferable contrast. That is, although the penalty is imposed, e.g., the scanning time is slightly prolonged, the MR signal from the fat component is suppressed and the MRA image without the loss of MR signal from the blood flow is obtained. [0136] FIG. 11 is a diagram showing an example of a sequence for describing a magnetic resonance imaging apparatus according to a second embodiment of the present invention. [0137] In the magnetic resonance imaging apparatus 20 A according to a second embodiment shown in FIG. 11 , a sequence generated by the imaging condition setting unit 44 and the fact that the fat-water separation does not used are different from those of the magnetic resonance imaging apparatus 20 shown in FIG. 1 . Other constructions and operations of the magnetic resonance imaging apparatus 20 A are not different from those of the magnetic resonance imaging apparatus 20 shown in FIG. 1 substantially. Therefore, only an example of sequence structure is shown, omitting explanation regarding a same component and operation of the magnetic resonance imaging apparatus 20 A. [0138] The magnetic resonance imaging apparatus 20 A uses the MT advantage, as an improving method for the contrast of an MRA image, in place of the fat-water separation. Referring to A) of FIG. 11 , a first sequence is set so that an MTC pulse P 1 is applied to the object P, as a pre-pulse, prior to the data acquisition of the blood flow image. Then, subsequent to the first sequence, for example, a second sequence for acquiring the image data on field echo (FE) method is set. [0139] Accurately, the first sequence shown in A) of FIG. 11 uses an SORS (slice-selective off-resonance sinc pulse) pulse for applying a slice gradient pulse P 2 for selective excitation of the MTC excitation surface at substantially the same timing as the MTC pulse P 1 . [0140] FIG. 12 is a diagram which compares the spectrum of the proton contained in water and that in a high polymer for explaining a MT effect obtained due to a MTC pulse on the sequence shown as A) in FIG. 11 . [0141] In FIG. 17 , the solid line shows the spectrum of the proton contained in water, and the chain line shows that in a high polymer. If a frequency shifted from 64 MHz, serving as the resonant frequency of the proton of water, by 500 Hz is selectively excited by an RF pulse, such an MT advantage is obtained that the MR signal level from the proton of the high polymer and the MR signal level from the proton of water are reduced respectively. [0142] In FIG. 12 the dashed line shows a spectrum of the proton contained in water after a MR signal level of the proton falls due to the MT effect. The chain double-dashed line shows the spectrum of the proton contained in a high polymer after a MR signal level of the proton falls due to the MT effect. [0143] The use of the above-mentioned MT advantage enables the imaging operation of images including an MRA image with the contrast according to the rate of high polymer (fat). [0144] Referring to FIG. 12 , with the MT advantage, such a feature is known that the MR signal level at the fat region having the high polymer component is excessively reduced, as compared with the MR signal level at the blood flow region having the water component. In order to obtain the MT advantage, the SORS pulse is generated as the first sequence so that the MTC pulse P 1 is applied to the object P as the pre-pulse. [0145] The scanning operation with applying the MTC pulse P 1 enables the imaging operation of the MRA image with the contrast according to the MT advantage. In particular, advantageously, the MRA image with the extraction of the thin blood vessel is obtained. [0146] To the contrary, depending on the fat rate, preferably, the MRA image or the like with the original contrast without the MT advantage is obtained as image for diagnosis. However, when mixedly existing the region at which it is preferable to apply the MTC pulse P 1 to obtain the MT advantage and the region at which it is preferable to acquire the MR signal without the MT advantage, one of the two imaging conditions is used. [0147] In this case, the region at which it is not preferable to apply the MTC pulse P 1 is set as the replacement area. The slice including the replacement area is subjected to both of the scanning operation with applying the MTC pulse P 1 and the scanning operation without applying the MTC pulse P 1 . The entire imaging area is subjected to the execution of scanning operation with applying the MTC pulse P 1 . That is, the imaging condition setting unit 44 generates the sequence without applying the MTC pulse P 1 for scanning the slice including the replacement area, as shown in B) of FIG. 11 . The sequences shown in A) and B) of FIG. 11 are selectively used every slice, and the scanning operation is executed. [0148] The replacement area of the three dimensional image data obtained by the scanning operation with applying the MTC pulse P 1 is replaced with the three dimensional image data obtained by the scanning operation without applying the MTC pulse P 1 . Thus, it is possible to obtain the image, such as the MRA image, using the MT advantage for only the proper area. [0149] Depending on the imaging condition, the entire imaging area is scanned without applying the MTC pulse P 1 . On the other hand, the slice including the replacement area is subjected to the execution of both the scanning operation with applying the MTC pulse P 1 and the scanning operation without applying the MTC pulse P 1 . The replacement area of the three dimensional image data obtained by the scanning operation without applying the MTC pulse P 1 may be replaced with the three dimensional image data obtained with applying the MTC pulse P 1 . [0150] That is, the magnetic resonance imaging apparatus 20 A according to the second embodiment is a device switching the existence of applying the MTC pulse P 1 , in place of switching the existence of the fat-water separation, serving as a different point of the imaging conditions in the magnetic resonance imaging apparatus 20 shown in FIG. 1 according to the first embodiment. [0151] As mentioned above, the difference of the imaging conditions at the replacement area is typically caused by the existence of the fat-water separation or applying the MTC pulse P 1 . Such imaging conditions can be variously set. For example, the imaging conditions are set to be different each other by combining the fat-water separation and the applying operation of the MTC pulse P 1 , thereby executing the scanning operation of the replacement area on the set imaging conditions. [0152] Further, the scanning operation may be executed under three or more different imaging conditions, and the three dimensional image data obtained under two or more arbitrary imaging conditions may be combined. For example, a number n of imaging conditions is set, including an imaging condition with the fat-water separation, an imaging condition without the fat-water separation, an imaging condition without applying the MTC pulse, and an imaging condition with applying the MTC pulse. Then, three dimensional image data obtained with applying the MTC pulse and without applying the MTC pulse and three dimensional image data obtained by switching the existence of the fat-water separation are individually combined, thereby obtaining the image with various contrasts. [0153] In the magnetic resonance imaging apparatuses 20 and 20 A according to the first and second embodiments, the three dimensional image data obtained under one imaging condition is partially replaced with the three dimensional image data obtained under another imaging condition. For example, when all the slices are imaged under varied imaging conditions respectively, in addition to the replacement, the three dimensional image data of the slices obtained under the imaging condition respectively may be simply combined, thereby generating new three dimensional image data.

A magnetic resonance imaging apparatus comprising an imaging condition setting unit, a gradient coil, a radio frequency coil, a data acquisition unit, an image reconstructing unit and an image data generating unit. The imaging condition setting unit sets a first imaging condition and a second imaging condition at least. The data acquisition unit acquires first magnetic resonance signal data corresponding to the first imaging condition and second magnetic resonance signal data corresponding to the second imaging condition. The image reconstructing unit reconstructs first three dimensional image data in accordance with the first magnetic resonance signal data and second three dimensional image data in accordance with the second magnetic resonance signal data. The image data generating unit combines the first three dimensional image data and the second three dimensional image data to generate third three dimensional image data.

CROSS-REFERENCE TO RELATED APPICATIONS [0001] This application claims priority to U.S. Provisional Patent Application No. 60/604,560 entitled “LAMINATED WEAR-RESISTANT ASSEMBLIES,” filed on Aug. 26, 2004 on behalf of Edward Williams, which is hereby incorporated by reference for all purposes. TECHNICAL FIELD [0002] The invention relates generally to wear-resistant and abrasion-resistant assemblies that can be affixed to a surface to extend the life of the equipment and increase the effectiveness of the equipment. BACKGROUND [0003] The use of wear-resistant material affixed to the working surfaces of equipment that is subject to high wear or abrasion from materials being processed is well known. Various ceramics, tungsten, or tungsten-carbide are some of the more commonly used materials. While wear-resistant materials are very hard, they tend to be expensive, brittle, and difficult to work with. For these reasons, equipment is rarely made from these materials. Depending on the arrangement and material used, such materials can be sprayed on in a thin coating, or sheets or tiles of such wear-resistant material can be affixed to working surfaces of equipment made from materials such as steel, aluminum or other metallic or non-metallic substances. Such wear-resistant materials have been used to prolong the life of a variety of equipment, such as drill bits, rotating fans, centrifuge conveyors, to name a few. [0004] For example, U.S. Pat. No. 4,003,115 to Fisher discloses a system whereby wear resistant-material is sprayed into a cavity created along the leading edge of a conveyor screw. However, in use, the amount of hardened material that can be secured to the surface of such equipment by spraying yields a thin coating of harder material on working surfaces. While this is satisfactory for some uses, many other uses require a thicker layer of wear-resistant material. For example, U.S. Pat. No. 6,648,601 also owned by the same assignee as the present invention, discloses affixing patterns of tiles of a wear-resistant material to rotating fan assemblies used for processing coal dust, which is highly abrasive, and would wear off a thin coating of hardened material in a very short time. Similarly, U.S. Pat. No. 5,380,434 to Paschedag discloses a system for affixing flat, wear-resistant tiles to the leading edge of a centrifuge conveyor screw, and U.S. Pat. No. 6,739,411, owned by the same assignee as the present application discloses affixing tiles of a wear-resistant material to the areas of drill bits that are subject to high wear. [0005] Because such wear-resistant materials tend to be very brittle, they are prone to fractures or cracking. Thus they can be difficult to work with. Additionally, depending on the equipment on which the wear-resistant materials are being used, and the product being processed in the equipment, cracked or chipped materials could contaminate the product, or cause damage in the equipment. [0006] One solution has been to affix them to a carrier, or backing, made of a material that is easier to work with, such as steel. However, there can be difficulties with securing the wear-resistant materials to the carrier, just as there are difficulties in securing the wear-resistant materials directly to the equipment. Because the wear-resistant materials are prone to fracturing or breaking, drilling holes through the materials to secure them to a carrier or other surface with fastening devices can be difficult, and result in a high incident of fracturing, cracking or chipping. One solution has been to solder, or braze the wear-resistant materials to the carrier. However, depending on the material characteristics of the carrier and the wear-resistant materials, it is necessary to heat the materials to a high temperature to perform the soldering or brazing. Because the materials expand and contract at different rates, after being secured, they contract at different rates. If the differences are great enough, the carrier will torque or shear as it cools, and the attached wear-resistant material can also bend, or will crack or fracture, or in some situations, the secure itself will fail and the two materials will detach from each other. [0007] Therefore, what is needed is a system and method for affixing wear-resistant members to equipment that is simple, cost-effective and easy to use. Such systems should provide for a method of securely fastening wear-resistant members to equipment, as wear-resistant materials are typically hard and can be brittle and break easily under certain circumstances. Such systems and methods should, among other things, reduce or eliminate instances of fracturing or cracking of the wear-resistant materials. Such systems should also reduce the possibility of the attached wear-resistant members becoming detached and contaminating product or damaging equipment. SUMMARY [0008] The present invention, accordingly, provides a multi-layer laminated wear-resistant assembly. The assembly comprises a bracket, typically made of steel or some similar material, which can be welded, soldered or glued and can be machined or manipulated. The bracket is layered between a plate wear-resistant material, such as tungsten-carbide on the front, and a third layer at the rear of the bracket, which can be made of the same material as the front layer, or of a different material having similar characteristics of expansion and contraction as the plate of wear-resistant material. The layers of the assembly are secured together by soldering, brazing or some other method. [0009] Because the bracket material is trapped between two layers of harder materials with similar characteristics, it does not warp or shear when the materials begin to cool after brazing, but stays “stretched” between the two layers of harder materials. This “stretched” state is due to the shrinkage differentials of the materials used in the layers of the assembly that occur after brazing when the assembly is cooling. When the entire laminated assembly has cooled, a stronger mechanism is achieved that is more resistant to cracking or fracturing because of the more flexible material that comprises the middle layer of the assembly providing a support structure. [0010] By creating a laminate of a bracket made of a more flexible material, such as steel or other material, with wear-resistant material as the top layer of the laminate, and a third layer of material on the rear side of the steel, a much stronger, more useful product is achieved than would be if only one of the materials was used alone. The face of hardened material prolongs the life of the equipment and increases the effective time of operation before repair or replacement is necessary. Additionally, the individual assemblies can be easily removed and replaced as assemblies wear over time, further increasing the life of the mechanism. [0011] In one preferred embodiment of the present invention, a laminated wear assembly is provided. A core member having a first and an opposite second face and having an attaching member extending substantially perpendicular from the second face to substantially form an “L” shape is included in the laminated wear assembly. Moreover, the core member further comprises a first coefficient of thermal expansion. Additionally, a first wear member is also included having a second coefficient of thermal expansion secured to a substantial portion of the first face, wherein the first coefficient of thermal expansion is greater than the second coefficient of thermal expansion. In addition to having a first wear member, there is also a second wear member having a third coefficient of thermal expansion secured to a substantial portion of the second face, wherein the second coefficient of thermal expansion is approximately equal the third coefficient of thermal expansion. The laminated wear assembly, too, is formed such that the core member remains substantially stretched at approximately room temperature. [0012] In another preferred embodiment of the present invention, the core member comprises a material selected from the group consisting of stainless steel, carbon steel, aluminum, and NiCroMoly. [0013] In yet another preferred embodiment of the present invention, the first wear member and/or the second wear member are made from a composition comprising at least tungsten-carbide. [0014] In another preferred embodiment of the present invention, the core member, the first wear member, and the second wear member are secured to one another by brazing, soldering, welding, or gluing. [0015] In an alternative embodiment of the present invention, a method of forming a laminated wear assembly is provided. A core member is formed having a first and a second opposing face with an attaching member extending substantially perpendicular from the second face to form an “L” shape, and having a first coefficient of thermal expansion. A first wear member is also formed having a second coefficient of thermal expansion, wherein the second coefficient of thermal expansion is less than the first coefficient of thermal expansion. Additionally, a second wear member is formed having a third coefficient of thermal expansion, wherein the second coefficient of thermal expansion is approximately equal to the third coefficient of thermal expansion. Onced formed, the core member, the first wear member, and the second wear member are heated to a sufficient temperature that causes the core member, the first wear member, and the second wear member to secure with one another and to form the laminated wear assembly. After heating, the laminated wear assembly is cooled to approximately room temperature so that the core member remains in tension in a tensile state of stress at approximately room temperature. [0016] Another alternative embodiment of the present invention provides a method of forming a laminated assembly. With this alternative embodiment, a core member, having a first and a second opposing face, a first wear member, and a second wear member are formed. Once formed, each of the core member, the first wear member, and the second wear member are elongated. Once elongated, the first wear member is secured to the first face, and the second wear member is secured to the second opposing face. The first wear member and the second wear member are then reduced, while the elongation of the core member is maintained. [0017] The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS [0018] For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: [0019] FIG. 1 is an exploded side view of an assembly embodying features of the present invention; [0020] FIG. 2 is a rear perspective view of an assembly of the present invention; [0021] FIG. 3 is a rear exploded view of an assembly embodying the features of the present invention; [0022] FIG. 4 is a front view showing several assemblies secured to the leading edge of a piece of equipment; and [0023] FIG. 5 is a side view of a secured assembly of FIG. 4 . DETAILED DESCRIPTION [0024] In the discussion of the FIGURES, the same reference numerals will be used throughout to refer to the same or similar components. In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without such specific details. [0025] Referring to FIGS. 1-3 of the drawings, the reference numeral 10 generally designates a laminated assembly of the present invention. The assembly 10 comprises a first wear member 30 , a core member 20 , and a second wear member or backing element 40 . [0026] The assembly 10 is essentially a bracket that can be affixed to machinery to protect wear surfaces. For example, assembly 10 can be affixed to driving faces of an extrusion screw, as shown in FIG. 4 . The assembly 10 is formed by sandwiching the core member 20 made of a workable material, such as steel, between the first wear member 30 and the second wear member 40 , where the core member 20 , the first wear member 30 and the second wear member 40 are secured to one another, such as by brazing, gluing, soldering, or welding. Typically, the first wear member 30 and the second wear member 40 are comprised of a hard material, such as tungsten-carbide. [0027] Specifically, each of the core member 20 and the first wear member 30 have first faces 20 b and 30 b and second faces 20 a and 30 a, respectively. In forming the assembly 10 , the second face 30 a of the first wear member 30 is secured to the first face 20 b of the core member 20 , and the second wear member 40 is secured to the second face 20 a of the core member 20 in slot 24 . However, as it can be seen in FIGS. 1-3 , second wear member 40 does not completely cover the second face 20 a of the core member 20 . There is an attaching member 22 extending substantially perpendicular from the second face 20 b of the core member 20 such that the core member 20 forms an “L” shape. The attaching member 26 would thus allow for a portion of the workable material, such as steel, to be exposed so as to attach to machinery, as shown in FIG. 4 , while the first face 30 b of the first wear member 30 faces outward and comes in contact with the admixture being processed. [0028] In the process of securing the layers of the assembly together, heating is commonly employed; moreover, it is not uncommon to utilize assembly 10 in heated environments. One of the reasons for employing the multiple layers of wear members is due to differing coefficients of thermal expansion of the dissimilar metals. Typically, the hard protective metals, such as tungsten-carbide, have a lower coefficient of thermal expansion than the more workable core materials, such as steel. The relative differential expansions/contractions usually cause bending or bowing, resulting in torsion, compression, and tension that can cause failure. Thus, as stated above, the second wear member 40 does not cover the entire second face 20 a of the core member 20 ; it covers enough area of the second face 20 a of the core member 20 to prevent the core member 20 from bending or bowing as the assembly 10 is heated or cools. Reduction in the relative size of the second wear member 40 can reduce costs because less material can be used to cover the rear side of the assembly 10 . [0029] Additionally, if the assembly 10 is to be secured to the underlying equipment by means of soldering or welding, in many cases, it is easier to weld the exposed material of the core member 20 on the rear side of the assembly 10 to the underlying equipment or machinery than having to weld the types of harder materials that typically comprise the second wear member 40 to standard equipment or machinery. In some cases, depending on the harder materials used, welding of those materials may not even be possible. [0030] Furthermore, as stated above, the layers of the assembly 10 are typically laminated together by soldering, brazing or other means that utilize heat. After they have been heated during one of these processes (or heated independently of the joining process), the dissimilar metals are secured together. As the assembly cools, the core layer 30 remains in an expanded or “stretched” state between the two outer layers 30 and 40 . In other words, once at room temperature, the core member 20 is in tension or in a tensile stress state in its major direction. Thus, additional, intentional residual stresses are added to any inherent residual stresses present in the assembly 10 . As an example, consider that core member 20 and second face 30 a are 1.5 inches in the major (longest) direction before heating, while second wear member 40 is 0.925 inches before heating. After lamination and cooling to ambient temperature, second face 30 a and the second wear member 40 return to 1.5 inches and 0.925 inches, respectively, but the core member 30 remains partially extended. Therefore, the assembly 10 has a dominant or major tensile stress, resulting from differential expansion (contraction) along the major dimension of the assembly 10 . [0031] Moreover, it is also possible to form each of the first wear member 30 and the second wear member 40 of multiple pieces. Depending on the conditions and circumstances of the particular application for the assembly 10 , flexibility may be desirable, which would be provided by replacing a single piece of hard material with multiple pieces of material. Specifically, as can be seen in FIG. 3 , the second wear member 40 is formed of two pieces. However, any number of pieces can be utilized. [0032] Additionally, the core member 20 may also have a variety of configurations. As shown in FIGS. 1-3 , a portion of the second face 20 a of the core member 20 is exposed. This type of configuration allows for additional welds to underlying machinery. However, it is also possible to completely cover both the first face 20 b and the second face 20 a of the core member 20 . [0033] As seen in FIGS. 4 and 5 , in operation, the core member 20 hangs over and is secured to the outer edge 102 of the equipment 100 , such as an extrusion screw, by means of spot welding of the attachment member 26 of the core member 20 to the outer edge 102 of the equipment 100 . Additionally, the bottom of the assembly 10 is spot-welded to the leading edge 104 of the equipment 100 . With this configuration, the core member 20 , is made of a material such as steel, which can be welded to the extrusion screw 100 . However, it can be appreciated that the assembly 10 can be secured to the equipment 100 by a variety of methods, including gluing, brazing, soldering or other securing methods. Another benefit of the present invention is that when an assembly 10 does wear and need replacing, this can be done easily in the field by soldering, welding or gluing a new assembly 10 to the equipment 100 . Because wear-resistant materials such as tungsten-carbide can be brazed, but cannot be welded, replacing surfacing material made only of tungsten-carbide in situ would be difficult, as brazing in typical ambient environments is difficult and does not always produce a strong bond. [0034] The front face 30 b of the first wear member 30 faces outward from the equipment 100 and comes in contact with the material being processed in the equipment 100 . As can be seen, a series of assemblies 10 are placed adjacent to each other and to provide a smooth continuous covering along the leading edge 104 of the extrusion screw 100 . As can be understood, the size and shape of assemblies used can vary in accordance with the size and shape of the equipment 100 . [0035] Thus, the arrangement of the present invention yields an assembly 10 of greater strength and resistance to cracking than use of a single layer of tungsten-carbide, and achieves rigidity from having a layer of more flexible material between two layers of harder material. [0036] It is understood that the present invention can take many forms and embodiments. Accordingly, several variations may be made in the foregoing without departing from the spirit or the scope of the invention. Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered obvious and desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.

Wear-resistant and abrasion-resistant assemblies can be affixed to surfaces of various pieces of equipment to extend the life of the equipment and increase its effectiveness. The assembly is a multi-layer composition of two harder materials that provide wear-resistance surrounding a material that provides strength and flexibility, as well as providing a means of attaching the assembly to the piece of equipment. When one or more assemblies does incur wear, assemblies can be replaced easily to further extend the life of the equipment.

BACKGROUND OF THE INVENTION This invention relates to the electrolytic recovery of metals and, more particularly, is directed to the stripping of electrolytic metal deposits as sheets from cathode plate base plates. In the electrolytic recovery of metals, such as zinc and copper, high quality metal is deposited on electrode plates such as mother plates, starting sheets or base plates, referred to hereinafter as cathode plates, which are made of suitable materials such as aluminum, stainless steel, or titanium. After a period of electro-deposition of metal on the cathode plates, the cathode plates are removed from the electrolytic cells and subjected to a mechanical stripping or peeling operation to remove sheets of refined metal from the cathode plates which are then returned to the cells. PRIOR ART The various mechanized methods and apparatus to facilitate the removal of metal deposits from cathode plates include alone or in combination, the use of impacting, pneumatic or hydraulic spray devices, suction cups, rolling, mangling or bending of the cathode plates and separating knives or wedges. One of the more prevalent methods and apparatus includes the use of knives or wedges. The use of knives or wedges in combination with one or more of the other methods noted above is disclosed, for example, in U.S. Pat. Nos. 3,332,128; 3,935,091; 3,950,232; 3,953,312; and Canadian Pat. No. 1,016,497. Some methods and apparatus are based on the sole use of one or more knives alone or in one or more pairs to separate the metal deposit from the cathode plate, such as disclosed in U.S. Pat. Nos. 1,525,075; 1,553,080; 3,625,806; 3,689,396; 3,847,779; 3,980,548; and 4,137,130. More specifically, U.S. Pat. No. 3,689,396 discloses an apparatus for vertically advancing cathode plates having a movable guard piece at one lateral edge of the cathode plate, means for moving the guard piece, a wedge shiftable relative to the zone at the guard piece to peel the upper edge of the deposit and a vertically moving blade to deflect the deposit from the cathode plate. According to U.S. Pat. Nos. 3,847,779 and 3,980,548 there are disclosed a method and an apparatus including a multiple station stripping unit having means to pivot a cathode plate holder (guard piece) having tapered surfaces for providing an upturned edge of deposited metal and including an enlarged portion adapted to be engaged for pivoting; means for inserting horizontal stripping knives which clamp onto the exposed plate and partially separate the deposit; and means for inserting main stripping blades and moving the inserted blades downwardly to complete the separation, the cathode plates being secured in each station. In connection with these patents, German Pat. No. 512,913 must be noted. This patent shows a removable edge stick with tapered faces which, upon removal of the edge stick from the electrode, leaves V-shaped grooves between deposits and base plate suited for inserting a stripping tool. According to U.S. Pat. No. 4,137,130, a single movement of a unitary stripping means causes a wedge to be inserted in a V-shaped groove between the cathode plate and the deposit and a blade propagates the separation. In the operation of conventional stripping machines, each cathode plate is clamped in a stationary position and the cathode plate edge is approached by a pair of knives which are open to ensure that the knives locate on each side of the cathode plate. The knives are stopped or slowed down, closed onto the cathode plate and then advanced for entering between the deposits and the cathode plate to commence stripping. This procedure is time consuming. In order for the knives to be able to close onto the cathode plate, the removed guard piece must expose an area of the cathode plate surface wider than that normally provided by the standard edge stick. This requires that the guard piece is wider than the edge stick and causes an increased invasion of the guard piece into the anode-cathode plate electric field which results in plating of metal onto the bevelled or tapered edges of the guard piece, often continuing onto the main body of the guard piece. This extended deposition causes undesirable encrustations which can cause electrical shorting, breaking of the guard piece when it is pivoted out of the way, as well as interference with the movement of the knives. The knives not only can be prevented from landing on the cathode plate but can also miss one side of the cathode plate altogether. The clamping or closing of the knives onto the cathode plate causes gouging on the cathode plate surfaces which leads to increased corrosion resulting in further damage to the surfaces, difficulties in stripping and shortened cathode plate life. Most stripping machines use either a chain conveyor or a walking beam in order to transfer the cathode plates through the stripping machine. These structures have serious drawbacks; a chain drive has a return section which interferes with the stripping knives and a walking beam is undesirably slow. STATEMENT OF INVENTION It has been found that the disadvantages of prior art apparatus can be substantially alleviated and the stripping of metal sheet deposits from cathode plates can be accomplished in a fast, simple and efficient manner by using a closed entry horizontal knife to effect initial parting of each deposit while partly outwardly bending the top portion of the deposit and then removing the deposits from the two sides of the cathode plate with vertical stripping knives without clamping of the cathode plate while controlling cathode plate sway. By providing a guard piece on the cathode plate edge with the same profile and width of and interlocked with the permanent edge stick, interference in the cathode plate-anode electric field and undesirable metal growths are eliminated. By using a closed entry knife to effect the initial parting of the deposit from the cathode plate and by the elimination of clamping of the cathode plates at the knives while controlling cathode plate sway, the time required to effect stripping can be shortened. By providing means to bend the deposits by the horizontally moving entry knives when the entry knives enter between the deposits and the cathode plate, the vertically moving main stripping knives can quickly and reliably remove the deposits from the cathode plate without stopping, thereby further reducing the stripping time. A simple transfer mechanism for advancing cathode plates through the stripping machine still further reduces stripping time. Accordingly, there is provided a method for stripping electro-deposited sheets of metal from cathode plates used in tne electrolytic recovery of metals, each cathode plate having a head bar at one end for vertical support of the cathode plate, opposite side faces with metal deposits thereon, and vertical side edges having edge sticks mounted thereon and a pivotal guard piece forming a separate upper portion of one of said edge sticks, said method comprising: advancing said cathode plates crosswise to the direction of travel sequentially through a plurality of equispaced stations in succession by means of a reciprocating transfer carriage, said plurality of stations consisting of a feed station, an initial horizontal parting station, a main vertical stripping station, and a discharge station; said transfer carriage mounted for horizontal reciprocal travel above a pair of parallel, spaced-apart slide bars over a distance equal to the distance between a pair of adjacent stations, said transfer carriage having means formed thereon for engaging a cathode plate head bar at each station for advance of the cathode plates on the slide bars to a successive station; actuating detent means operable into and out of engagement with the opposite side edges of the cathode plates at the initial horizontal parting station and vertical stripping station for positioning the cathode plates and preventing sway of said cathode plates at each of the said stations; pivoting said guard piece upwardly away from the side edge of the cathode plate; initially parting the top edge of the metal deposit on each side face of the cathode plate from the cathode plate and bending the said top edges outwardly away from the cathode plate to form a gap between the top edges and the face of the cathode plate at the initial horizontal parting station; vertically reciprocating main stripping knives to engage the deposited metal at the gap on each side face of the cathode plate and strip metal deposits downwardly from each side face of the cathode plate for removal of the said metal deposits therefrom at the vertical stripping station; and removing stripped cathode plates at the discharge station. The method may include the additional step of positioning the cathode plate and preventing sway thereof while pivoting the guard piece onto the vertical side edge to form the separate upper position of the one edge stick at a replacement station after stripping of the cathode plate. The apparatus of the invention for stripping electro-deposited sheets of metal from cathode plates comprises in combination: a frame having a plurality of equispaced stations therein; means for advancing said cathode plates crosswise to the direction of travel sequentially through the plurality of equispaced stations in succession, said plurality of stations consisting of a feed station, an initial horizontal parting station, a main vertical stripping station, and a discharge station, said advancing means comprising a pair of parallel spaced-apart slide bars for supporting the head bars of cathode plates; a transfer carriage mounted above said slide bars for horizontal reciprocal travel over a distance equal to the distance between a pair of adjacent stations, said transfer carriage having means formed thereon for engaging a cathode plate head bar at each station for advance of the cathode plates on the slide bars to a successive station, said advance extending substantially the distance between two adjacent stations during reciprocal travel of said carriage; detent means operable into and out of engagement with the opposite side edges of the cathode plates at each of said vertical stripping and horizontal parting stations, for positioning the cathode plates and preventing sway of said cathode plates at each of the said stations; means for pivoting said guard piece upwardly away from the side edge of the cathode plate; means horizontally reciprocal adapted to extend across said cathode plate for initially parting the top edge of the metal deposit on each side face of the cathode plate from the cathode plate and for bending the top edges outwardly away from the cathode plate to form a gap between the top edges and the faces of the cathode plate; means at the main vertical stripping station vertically reciprocal for engaging the deposited metal at the gap on each side face of the cathode plate and for stripping metal deposits downwardly from each side face of the cathode plate for removal therefrom; and conveyor means for removing cathode plates and deposits at the discharge station. Preferably means are provided at a replacement station for pivoting said guard piece onto the vertical side edge to form the separate upper portion of the one edge stick while positioning the cathode plate and preventing sway thereof prior to transfer onto the conveyor means for removal of stripped cathode plates at the discharge station. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in detail with reference to the accompanying drawings wherein: FIG. 1 is a perspective view of the stripping apparatus of the present invention showing the components in their retracted positions; FIG. 2 schematically shows the operative stations and the position of the transfer carriage within the stripping apparatus immediately prior to a transfer of cathode plates from one station to the next station; FIG. 3 schematically shows the position of the transfer carriage and placement of cathode plates immediately after a transfer of cathode plates as the transfer carriage begins the return cycle; FIG. 4 is a side elevation of the stripping apparatus; FIG. 5 is an end elevation of the stripping apparatus; FIG. 6 is a perspective view of an upper portion of a cathode plate; FIG. 7 is a persective view of the operative components at the initial parting stage; FIG. 8 illustrates the bending of initially parted deposit shown in FIG. 7; FIG. 9 shows an enlarged detail of the closed entry, initial parting knife illustrated in FIG. 7; FIG. 10 is a perspective view of the main stripping knives; FIG. 11 is a perspective view of the bottom discharge assembly of the main stripping station; and FIG. 12 is a vertical section taken along the line 12--12 of FIG. 11. FIG. 13 is a perspective view of a portion of an embodiment of the stripping apparatus illustrating the upper portion of a bottom discharge chute at the main stripping station; FIG. 14 is a side elevation of the bottom discharge chute; FIG. 15 is a perspective view of the lower portion of the bottom discharge chute; FIG. 16 is a side elevation of the apparatus shown in FIG. 15 illustrating the operation of the discharge mechanism; FIGS. 17-20 are detailed side elevations of the trap mechanism at the base of the vertical portion of the discharge chute illustrating the operation of the said trap mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the drawings and particularly FIGS. 1-5, the apparatus for stripping metal deposits from cathode plates generally comprises the machine depicted by numeral 10 which is in-line with a conveyor 12 for feeding cathode plates 14 sequentially thereto and a conveyor 16 for conveying stripped cathode plates from the said machine. Cathode plates 14 having head bars 18 and metal deposits on side faces 20, 22 are transferred from feed conveyor 12 by a transfer mechanism 24, comprising reciprocating transfer carriage 26, onto a pair of spaced-apart parallel, fixed slide bars 28. Transfer carriage 26 has rollers 23 provided thereon adapted to co-act with carriage rail 25 secured to frame 36. Piston-cylinder means 70 (FIGS. 2 and 3) are provided between carriage 26 and frame 36 for advancing and retracting the carriage in guided, horizontal travel. The feed conveyor 12 comprises a pair of continuously moving conventional endless chain conveyors 30 passing over sprocket wheels 32 in proximity to each of slide bars 28, one of which is shown in FIG. 1. By keeping the chain conveyor 30 moving continuously at a slow speed, the risk of initiating swing in the cathode plates is reduced. The speed of the conveyor is adjusted to suit the duration of the stripping cycle, to be described. The cathode plates are intermittently advanced by the reciprocating carriage 26 over the slide bars 28 from a feed station A through an initial parting station B, which comprises means to remove a cathode plate guard piece, and a horizontal, initial parting, closed entry knife 94; a main stripping station C, which comprises vertical main stripping knives 29 which complete the stripping of the deposits; and a cathode plate guard replacement station D. The stripped cathode plates are then moved by the carriage 26 from the slide bars 28 onto a transverse conveyor 16 at a pick-up station E for passing the cathode plates to a subsequent operation or returning the cathode plates to the electrolytic process. The success of the stripping machine of the present invention is achieved in part by the simple, quick and accurate method in which the cathode plates are moved from one station to another by the transfer mechanism and by the rapid separation and removal of metal deposits from the cathode plates. CATHODE TRANSFER MECHANISM With particular reference now to FIGS. 1, 4 and 5, the pair of spaced-apart, parallel, fixed slide bars 28 are secured, one on each side, to the interior of frame 36 of the stripping machine and extend horizontally from sprocket wheel 32 at one end 38 of frame 36 in alignment with chain conveyor 30 to project beyond the opposite end 40 of frame 36. The thin slide bars 28 occupy little space and present no interference in either the initial parting station B or the main stripping station C to the stripping of the cathode plates. Four partly rotatable, equispaced pawls or dogs 42, which are pivotally mounted on each side of the interior of the stripping machine on reciprocatable transfer carriage 26, depend downwardly from horizontal side members 27 towards each cathode plate head bar. The rotation of dogs 42 is limited by stops 43 on the frame of carriage 26 such that the dogs can advance cathode plates to the next station when carriage 26 advances and the dogs can pivot and move over the top of cathode plate head bars when carriage 26 is retracted to its starting position. A spring 44 on each of the dogs 42 pushes the dogs against stops 43 preventing the dogs from remaining in an elevated position. Each dog engages and pushes the head bar 18 of a cathode plate 14, shown by ghost lines in FIGS. 4 and 5, on the fixed slide bars 28 from one station to the next station. The transfer carriage 26 moves a set of four cathode plates with each reciprocation; a set of cathode plates comprising one cathode plate 14a moved from conveyor 12 onto slide bars 28 at the feed station A, a cathode plate 14b at the intiial parting station B, a cathode plate 14c at the main stripping station C and a cathode plate 14d at the replacement station D (FIG. 2). When reciprocating, the transfer carriage 26 advances by means of the dogs 42 a set of cathode plates forward to the next successive station, moving the first cathode plate 14a from station A to station B and the last cathode plate 14d at station D from the slide bars 28 onto conveyor 16 (FIG. 3). The cathode plates are laterally guided by fixed guides 31a and 31b secured to the interior of frame 36, one on each side. Both guides extend horizontally from sprocket wheel 32 at end 38 of frame 36, guide 31a to just past main stripping station C (FIG. 1) and guide 31b (FIG. 5) to end 40 of frame 36. Both guides are positioned inside and below the slide bars 28 such that the guides are close to the vertical cathode plate edges. Guides 31a and 31b provide lateral guidance and centering of the cathode plates when they are moved over the slide bars 28. Guide 31b also provides a counterface when horizontal knives 94 move onto the cathode plate surfaces. An upper shaft 46, one on each side of frame 36, with three equispaced detents 48a, 48b and 48c projecting laterally therefrom, is mounted for rotation in journals 50, 52 above each slide rail 28. A corresponding shaft 60 with three equispaced, laterally projecting detents 62a, 62b and 62c is mounted for rotation in journals 56, 58 just above the plane of the bottom edge 64 of cathode plates 14 (FIG. 4) at each side of frame 36 below upper shafts 46. Lower detents 62a, 62b and 62c corresponding to upper detents 48a, 48b and 48c are spaced along tne shafts from each other the same distance as the distance between the initial parting station B and the main stripping station C. The detents are lined up so that, when the shafts 46 and 60 are rotated by piston-cylinder assemblies 66, 68, the detents locate and engage the cathode plate head bars and bottom edges at the initial parting station B, the main stripping station C and the replacement station D. Upper detents 48a , 48b and 48c are aligned to position a cathode plate accurately at each of these stations. Because the transfer carriage 26 with dogs 42 only pushes the tops of the cathode plates 14, the bottom edges of the cathode plates are delayed in forward travel by detents 62a , 62b and 62c. If the bottom edges were not restrained, the lower portions of the cathode plates would continue travelling after the tops have been stopped. This would cause considerable cathode plate sway which cannot be prevented by holding the cathode plate head bars against the upper detents 48a, 48b and 48c with dogs 42. To prevent cathode plate sway, lower detents 62a, 62b and 62c are introduced into each cathode plate path closer to the oncoming cathode plate than the corresponding upper detents so that the bottom edges of the cathode plates will rest against the detents by gravity rather than bounce back and forth against the detents. For very fast transfer of the cathodes plates, the lower detents 62 preferably have a damping device (not shown) such as, for example, a spring or a rubber buffer on the face of each lower detent which will contact the cathode plate to prevent the plate from bouncing. As described above, lateral cathode plate movement is limited by guides 31a and 31b. Thus, when a cathode plate 14 is delivered to the starting point on the fixed slide bars 28 in feed station A by chain conveyor 30, the dogs 42 of carriage 26 pass over head bar 18 to engage the rear side of the head bar. While this occurs, the detents on shafts 46 and 60 remain swung out of the path of the cathode plates. As soon as the transfer carriage 26 from which the dogs depend is pushed forward by the actuation of piston-cylinder assembly 70 (FIG. 2) secured thereto, shafts 46, 60 rotate to swing the detents depending therefrom into the path of the cathode plates. Just before the cathode plates reach the upper detents a shock absorber 72 mounted on carriage 26 abuts a stop 74 on the main frame 36 of the stripping machine (FIG. 1). The shock absorber decelerates the cathode plates and cushions the impact while permitting maintenance of pressure on the head bars 18 so that they are held in place and are prevented from bouncing or swinging when they are subsequently contacted by the parting knives and the main stripping knives, to be described. The detents are installed on the machine such that the cathode plate head bar 18 in main stripping station C in particular is aligned perfectly with the main stripping knives. The vertical, main stripping knives depicted by numeral 29 are sensitive to the position of the cathode plate and also to the amount or degree of sway. If the cathode plate is not accurately positioned at the station or if it is swinging at the time of actuation of the knives, one knife may land on top of the head bar and stripping will not occur on one side of the cathode plate. This leads to cathode plate bending by the knife on the side being stripped. It is, therefore important that dogs 42 of the transfer carriage 26 and the top detents 48b are aligned accurately with the vertical main stripping knives 29. A small tolerance in alignment can be accepted for the cathode plate at the initial parting station B because the initial parting knife 94 will be guided in its travel and is flexible enough to absorb some misalignment and even a minor amount of sway. The detents 48b and the corresponding dogs 42 remain in position to hold cathode plate 14 therebetween until the main stripping knives, to be described, in the main stripping station C have completed their downward stroke. As soon as the stroke is completed, the transfer carriage 26 with dogs 42 is retracted to its starting position, (FIG. 2), the dogs 42 pivoting and lifting over the cathode plate head bars 18 on the return travel while the upper and lower detents are moved out of the path of travel of the cathode plates by rotation of shafts 46, 60. The movement of the transfer carriage 26 from its starting position as shown in FIG. 2 to its forward position as shown in FIG. 3, moving a set of cathode plates from one station to the next, takes about 11/2 seconds. At about one-half second after the transfer carriage initiates forward movement, the three upper detents 48a, 48b and 48c, and the three lower detents 62a, 62b and 62c, move into the path of the cathodes plates. THE INITIAL PARTING STATION B With reference now to FIGS. 6-9, two main functions occur at the initial parting station B: 1. The guard piece 90 on one of the vertical edges 92 of a cathode plate is rotated to a horizontal position; the completion of rotation being checked by a sensor 100 (FIG. 1); and 2. The closed entry, initial parting knives 94 enter horizontally onto the cathode plate 14 to effect the initial parting of the metal sheet deposits 96, one of which is shown, and to bend the deposits outwardly at the top portion 98 to permit easy access for the vertical main stripping knives 29. In more detail, as soon as the cathode plate 14 arrives at the initial parting station B, the guard piece removal mechanism 102 having forked extension 104 adapted to span the thickness of cathode plate 14 is extended by hydraulic piston-cylinder assembly 106 to abut the top portion 108 of pivotally mounted guard piece 90 to rotate and raise body 110 of the guard piece 90 from the cathode plate edge 92 into a substantially horizontal position so that the initial parting knives 94 can engage the cathode plate. A sensor 100 checks that the pivoting of the guard piece into a substantially horizontal position has been completed. If the pivoting has not been completed, the horizontal parting knives 94 are prevented from extending. The guard piece 90 is designed with the same profile as the edge stick 114, thus avoiding any wings and peanut-like encrustations on the metal sheet deposits 96 formed during electrolysis. In addition, the bottom of body 110 of the guard piece 90 interlocks with the top 115 of the fixed edge stick 114 by means of a slight interference fit. This prevents the guard piece 90 from floating away from the cathode plate 14 when it is submerged in the electrolyte. After the guard piece 90 is raised, the closed entry, horizontally moving, initial parting knives 94 are extended by a piston-cylinder assembly, not shown, and are moved onto the cathode plate to part the deposits 96 from the cathode plate faces across the upper portion of the cathode plate at the tops 98 of the deposits. The initial parting knives 94 are horizontally moving, closed entry knives which comprise two interdependent components each composed of a leaf spring 120 attached to a common cross-head support (not shown) and individual nosepieces 122, rollers 124 and guide horns 126, shown most clearly in FIG. 9. The nosepieces 122 have a sharp leading edge 128 with which to penetrate between the deposit 96 and adjacent cathode plate face. Two rollers 124 are journalled into laterally-spaced recesses 130 in each nosepiece 122 at upper and lower faces 132, 134 of the nosepiece 122 such that the rollers 124 slightly protrude above the inner sliding faces 136 of the nosepieces. The rollers 124 prevent the steel nosepieces 122 from galling or scratching the cathode plate surfaces 20,22. The guide horns 126 are mounted onto the top face 132 of each nosepiece 122, their inner surfaces 140 being flush with the inner surfaces 136, i.e. facing surfaces, of the nosepieces 122. The guide horns 126 have a leading edge 142 and a bevelled edge 144 such that a V-shaped opening 146 is defined between the guide horns 126, FIG. 7. The guide horns 126 ride on the cathode plate faces 20,22 above the tops of the deposits 96. Their purpose is to align the nosepiece 122 with the cathode plate 14 so that the leading edge 128 of each nosepiece 122 misses the cathode edge 92 and enters between the deposit 96 and the adjacent cathode plate face 22. The leaf springs 120 of the closed entry knives bias and maintain the two nosepieces 122 against the faces 20,22 of the cathode plate as the knives engage the cathode plate, enabling the nosepieces 122 to straddle the cathode plate and enter behind the deposits 96. In addition, the springs 120 provide sufficient flexibility to allow each nosepiece 122 to ride on the cathode plate 14 if the nosepiece should fail to penetrate and enter under the deposit 96 and thus be deflected to the outside of the deposit. The closed entry, initial parting knives 94 are assembled such that the leaf springs 120 keep the rollers 124 in the nosepieces 122 in contact with each other. Upon moving forward, the guide horns 126 separate the nosepieces 122 when the bottom of the V-shaped opening 146 between bevelled edges 144 reaches the edge 92 of the cathode plate 14, so that the leading edges 128 miss the cathode plate 14 and the nosepieces 122 can enter between the deposits 96 and the cathode plate 14. As soon as entry is made, the rollers 124 approach and reach the cathode plate edge 92 and roll onto the cathode plate surfaces 20,22. The leading edges 128 of the nosepieces 122 are consequently lifted slightly off the cathode plate surfaces 20,22 preventing scratching or galling of the surface metal. The design of the initial parting knives has a number of advantages. The guides horns 126, in addition to opening the nosepieces 122 to miss the cathode plate, also centre the cathode plate between the knives in case it is misaligned. The closed entry knives need no surface to land on because of the effective guidance provided by the guide horns 126, and if wings should be present on the deposits, the wings tend to assist in the entry of the knives into the cathode plate-deposit interface. The speed at which the initial parting knives can approach the cathode plate can be high, thus giving a short cycle time. This is much shorter than the time required for the subsequent stripping at the main stripping station C. The initial parting station B can, therefore, also incorporate the guard piece removal mechanism 102 without incurring any loss in cycle time. The initial parting knives 94 bend the top portions 98 of deposits 96 away from the cathode plate 14 (FIG. 8). This speeds up the subsequent operation of the stripping with the vertical main stripping knives at the main stripping station C. If this were not done, considerable time would be wasted in positioning the main stripping knives behind the deposits. In some operations, the deposits tend to spring back onto the cathode plate faces and it is advantageous in such cases to bend the deposits more positively to ensure a gap between the top portions 98 of deposits 96 and the cathode plate faces 20 and 22. This can be achieved by providing the optional yokes 112 which extend from both sides of frame 36 to engage and envelop a short length of the vertical edge sticks 114 and underlying cathode plate edges. The yokes 112 are each carried by piston 116 (both shown in ghost lines) and operated hydraulically by a cylinder (not shown). Yokes 112 are positioned at the top portion of the cathode plate 14 below the initial parting knives 94 when the knives have moved onto the cathode plate 14. The yokes 112 serve as stops or fulcrums over which the deposits 96 are bent. The width or spacing of the yoke extensions 113 is selected so that the initial parting knives 94 bend the deposits 96 slightly over the extensions 113, as shown in FIG. 8. This ensures there is a gap between the top portion 98 of the deposits 96 and the cathode plate faces after the initial parting knives 94 and the yokes 112 have been withdrawn. THE MAIN STRIPPING STATION C With reference now to FIGS. 4, 5 and 10-12, after the closed entry knives have initially parted the deposits 96 and outwardly bent the top portion 98 of the deposits 96, the cathode plate is moved to the main stripping station C where the vertical main stripping knives 29 are lowered to enter in between the bent deposits 96 and the cathode plate faces 20,22 to complete the separation and removal of the deposits. In order to achieve complete stripping, the knives 29 must travel vertically down the full length of the cathode plate 14 and return upwards before the next cathode plate can be brought into the main stripping station C. On large cathode plates, the distance travelled by the knives 29 can be in the order of five meters which requires a travel time in the order of six seconds. This exceeds the times required in any of the other stations so that any delays which prevent the vertical knives from descending or retracting will add to the cycle time and decrease productivity. As soon as the cathode plate has been transferred from the initial parting station B to the main stripping station C, the vertical knives 29 immediately descend to complete stripping of the deposits and then retract. The knives are accelerated as fast as possible to full speed, then retracted as fast as possible as soon as the stripping stroke is completed. In order to accomplish this consistently, the cathode plate must be accurately positioned, no swinging of the cathode plate must occur when the vertical knives come down over the head bar of the cathode plate, the edge sticks must be retained on the cathode plate, and the released deposits must not interfere with the stripping operation. Accurately positioning of the cathode plate is effected by the transfer mechanism, as has been described above and, in order to prevent swaying of the cathode plate. Tne bottom detents 62b as shown in FIG. 1 are introduced at each side of the bottom of the cathode plate to maintain the cathode plate out of vertical plumb, as described above. The bottom detents 62b thus in cooperation with the top detents 48b hold the cathode plate 14 slightly off the vertical with the bottom of the cathode plate 14 slightly closer to the initial parting station B than the cathode plate head bar. With the cathode plate accurately positioned and stationary, the vertical, main stripping knives 29 are brought down. The knives 29 are hingeably connected via knuckle joints 206 for vertical movement by rods 161 to cylinders 162, FIGS. 4 and 10. Knives 29 are biased together under constant spring pressure by torque springs 164 for closing on cam 166 which is located just above the head bar 18. The springs 164 and cam 166 are of known design. Cam 166 is fixed to the frame 36 of the stripping machine by support bar 167 and does not interfere in any way with the transfer of cathode plates. The cam 166 keeps the knives 29 open and separated until the leading edges 168 of the knives 29 pass below the top 170 of the head bar 18. The knives 29 then immediately close in on the opposite cathode plate faces 20, 22. Because there is a bare and unobstructed portion of the cathode plate between the bottom of the head bar and the top portion 98 of the bent-away deposits 96 as a result of the initial parting and bending, the vertical knives 29 are assured entry between the deposits 96 and the cathode plate faces 20,22 without in any way having to stop or slow down, or require the use of auxiliary equipment. While the deposits 96 are being parted from the cathode plate faces 20,22, they are supported by a support plate 172 (FIG. 1). Support plate 172 is pivotally and fixedly positioned on shaft 174 mounted in journals 175, one on each side of frame 36, from a normal at-rest position as shown in FIG. 11, to an upper position as shown in FIGS. 1 and 12. Support plate 172 consists of a flat-plate section 176 having a transverse ridge 177 and a contiguous, slightly curved extension 178 having two spaced-apart, up-curved extensions 179 each with an upstanding terminal edge 180. The up-curved extensions 179 are spaced apart so as to clear the brackets (to be described) on a lowering conveyor 186 when plate 172 is pivoted to its lower position. Because support of the deposits is not necessary until the end of the stripping stroke by the main knives 29, the support plate 172 swings up under actuation of a piston-cylinder assembly 173 for ridge 177 and upstanding edges 180 to straddle a cathode plate after knives 29 have commenced their downward travel, thereby avoiding delays. The deposits are retained on the plate between ridge 177 and upstanding edges 180 which prevent the separated deposits from moving back and forth on the support plate 172. As the vertical knives 29 push downwardly between the deposits 96 and the cathode plate 14, the deposits 96 are forced outwardly from the cathode plate. To avoid interference with adjacent parts of the stripping machine, guide forks 181, which are situated about midway of the cathode plate and pivotally mounted, one on each side of frame 36, for actuation by piston-cylinder assembly 182, swing in on each side of the cathode plate as soon as the vertical knives start descending to laterally support the deposits 96. A cross bar 183 between the prongs of forks 181, together with the positive placement of the deposits on support plate 172, prevents any sideways movement of the deposits which may have been caused by uneven loosening of the deposits from the cathode plate due to the occasional tendency for deposits to adhere more in certain areas of the cathode plate than in others. The guide forks 181 also prevent overstressing the knife blades 29, torque springs 164 and driving cylinders 161, 162. The deposits on each side of the cathode plate are in fact one deposit plate joined at the bottom. Without the guide forks, the deposits would bow outwards as knives 29 approach the bottom of the cathode plate. The knife blades would then slow down and the knuckle joints 206 bow outwards with the deposits. This puts severe stress on the knife blades, torque springs and driving cylinders. With the guide forks in position, the knuckle joints are prevented from swinging outwards and the knives push down to complete the stripping and sometimes even cut through the bottom joint between the two deposits. The guide forks 181 remains in the upward, supporting position until the deposits are being lowered by lowering conveyor 186. An optical sensor, not shown, senses when knives 29 have completed their downward travel and signals cylinders 162 to retract knives 29 to their upper position. Lowering conveyor 186 comprises a number of transverse plates 187 mounted in parallel, closely spaced-apart relationship on a pair of spaced-apart conveyor chains 188. A plurality of plates 187 has three up-turned angle brackets 189 mounted thereon in spaced-apart relationship such that the curved extensions 179 of curved section 178 of support plate 172 can pass between them. Tne plates 187 which have brackets 189 mounted thereon are distanced apart slightly more than the height of a cathode deposit. Angle brackets 189 are adapted to receive the lower edges of the stripped metal deposits 96 and to lower the deposits from the stripping machine. To ensure that the deposits are received in angle brackets 189, two curved guides 190 are mounted on cross support bar 191 of frame 36, one on each side of support plate 172 (FIGS. 11 and 12), and two inverted hook-shaped guides 192 are mounted on cross support bar 193 of frame 36 in alignment with curved guides 190 and are curved over lowering conveyor 186. Curved guides 190 and hook-shaped guides 192 are curved down toward each other defining a funnel-shaped gap 194 to guide the deposits onto the brackets 189 of the conveyor. Further guidance is provided by cables 195, one attached to the end of each of hook-shaped guides 192 and extending downwardly over plates 187 between angle brackets 189. After deposits 96 have been separated from cathode plate 14, support plate 172 pivots downwardly, activated by assembly 173. The curved extensions 179 of plate 172 moved between brackets 189 and the deposits are guided by the pivoting of plate 172 and by guides 190 and 192 into brackets 189. As soon as deposits 96 are placed in brackets 189, the conveyor lowers the deposits from the stripping machine. Plate 172 is pivoted down sufficiently to clear the conveyor 186 and the deposits 96 on the conveyor. While the deposits are being lowered, assembly 182 is activated to lower the guide forks 181 into their down position. When the deposits have been lowered sufficiently, the transfer carriage 26 is activated to return to its starting position and the shafts 46 and 60 are rotated to move the detents 48 and 62 out of the path of the cathode plates. Carriage 26 is then activated to advance a set of cathode plates through the stripping machine, the cathode plate from which the deposits have just been removed being advanced forward to replacement station D. REPLACEMENT STATION D To replace the guard piece 90 onto the cathode plate 14, the guard piece 90 is first rotated from the horizontal position shown in FIG. 7 downwards through about 60 degrees. The rotation is effected by a stationary cam 200 secured to slide bar 28, which engages the upper surface of the guard piece while the cathode plate is moving from the main stripping station C to the replacement station D, to depress the guard piece. A hydraulically-actuated hammer 202 pivotally mounted on the frame 36 at station D then lightly pushes or taps the guard piece at a right angle to the cathode plate edge onto the cathode plate edge and in interlocking engagement with the cathode plate edge stick 114. PICK-UP STATION E The stripped cathode plate is pushed from slide bars 28 by the last pair of dogs 42 on transfer carriage 26 onto conveyor 16 for transporting the stripped cathode plate 14 from the stripping machine to a subsequent operation or to the electrolytic cells. The pick-up conveyor 16 may be a monorail conveyor, as shown in FIGS. 2-4, or a chain conveyor similar to feed chain conveyor 30. A detent or stop 204, FIG. 4, mounted on frame 36 steadies cathode plates 14 as they are conveyed from the stripping apparatus. All the foregoing description is with reference to a preferred embodiment of the invention, but it is to be understood that changes and variants may be introduced which are equivalent from the point of view of the function and structure, without falling thereby outside the scope of the invention. For example, the guard piece could be moved from and replaced on the cathode plate edge by means outside the stripping machine in which case the replacement station would not be necessary within the confines of the stripping machine. DISCHARGE CHUTE Removal of deposits 96 from a cathode plate 14 may be effected at the main stripping station C by the embodiment of the invention to be described with reference to FIGS. 13-20. Generally, stripped metal deposits are removed by a discharge chute disposed below the vertical stripping station. The discharge chute comprises a plurality of slide rails, each having an upper, an intermediate and a lower section. Trap means are disposed at the upper section for interrupting the fall of the discharging deposits. Speed regulating means are provided at the lower section for controlling the discharge speed of the deposits from the chute. With reference now to FIG. 13, arrow 300 indicates the movement of cathode plates bearing deposits towards the stripping station and arrow 302 indicates the vertically downward movement of stripped deposits into the upper portion of discharge chute 304. Stripped deposits are guided in their downward travel by a pair of opposed elongated U-shaped guides or forks 306, one of which is shown, adapted to be extended as shown during the stripping operation by downward pivotal movement of pivotally-mounted support arms 308 by rotation of shaft 312 by means of piston-cylinder assembly 310. Chute 304 comprises a plurality of equispaced slide rails 312, preferably three slide rails, having their base flanges 318 secured to a transverse support plate 320. The upper portions of rails 312 are substantially vertically aligned in a common plane extending across the chute opening 322 with the exposed surfaces 324 of the rails disposed to one side of a cathode plate located in the stripping station such that stripped deposits, indicated by numeral 326 in FIG. 14, will fall between rail surfaces 324 and a pair of opposed stationary trap arms 328 affixed to frame member 191. Trap arms 328 are inclined at a small angle of about 5° from the vertical towards rails 312 to guide stripped deposits 326 onto opposed pivotal trap arms 330 which are inclined at a small angle of about 5° away from vertical rails 312. Pivotal trap arms 330 are pivoted at their upper ends at 332 and define with stationary trap arms 328 a wedge-shaped trap depicted by numeral 334 for temporarily capturing deposits 326 at trap mechanism 336 located at the bottom of vertical rail section 338. Trap mechanism 336, shown most clearly in FIGS. 14 and 17-20, includes in addition to stationary trap arms 328 and pivotal trap arms 330 a transverse trap or detent plate 339 pivoted at 340 at the base of stationary trap arms 328 to extend across the width of the chute. The free end 342 of plate 339 is adapted to seat in notches 344 formed in the lower ends of pivotal trap arms 330 whereby deposits descending into the trap are stopped at plate 339, as shown in FIG. 18, to break their fall. Double-acting hydraulic piston-cylinder assembly 350, shown most clearly in FIGS. 13 and 14, is pivotally mounted at one end on frame 352 and at the other end on bracket 354 extending from transverse arm 356 secured to pivotal trap arms 330 by connectors 358, to move the trap arms 330 away from stationary trap arms 328 releasing detent plate 339 from notches 344 and permitting said plate to pivot downwardly, FIG. 19, to release deposits supported thereby. Deposits 326 continue their descent down the intermediate curved section 360 of the rails through about 90° to the horizontal discharge rail section 362 with speed regulating means, to be described. Push rod 364, pivotally mounted at one end on bracket 354 and extending through guide sleeves 366, 368 on stationary support 369, is adapted to actuate limit switches 370, 372 operatively connected to piston-cylinder assembly 350 to stop the outward travel of pivotal trap arms 330 and to reverse assembly 350 for return of said pivotal trap arms to the position shown in FIG. 20. Concurrent with retraction of assembly 350, double-acting piston-cylinder assembly 374 is activated by push rod 375 to extend piston 376 and move C-shaped actuator 378 pivotally mounted on at the base of arms 328 in a clockwise direction as viewed in FIG. 20 to reposition detent plate 339 to its normal at-rest horizontal position in notches 344. Push rod 375, slidably mounted for linear reciprocal travel in guide sleeves 377, 379, interacts with limit switches 381, 383 to stop the extension of piston rod 376 and to reverse assembly 374 for return of actuator 378 to its normally at-rest position shown in FIGS. 17, 18. A plurality of equispaced lower wheels 380 journalled on a common axle 385, preferably a wheel 380 adjacent each rail 312, FIGS. 14-16, extend slightly above the bearing surfaces 324 of rails 312 to frictionally engage the underside of deposits 326 as they pass between lower wheels 380 and pivotally-mounted plurality of opposed upper wheels 382 journalled on common axle 384 carried by spaced-apart pivot arms 387, one of which is keyed on shaft 392. Upper wheels 382 pivot substantially vertically upwardly, FIG. 16, sufficiently to allow deposits 326 to pass through to a stacker, not shown, under the downward bias of hydraulic spring 386. Hydraulic spring 386 has piston rod 388 connected to crank 390 which in turn is keyed to shaft 392 for maintaining a downward, or clockwise bias as viewed in FIGS. 15 or 16, on axle 384 and wheels 382. Either one or both axles 384 and 385 has a hydraulic or electric drive motor 396 operatively connected thereto to accelerate or decelerate, as necessary, the discharge speed of the deposits between the opposed sets of wheels to the peripheral velocity of the wheels for a desired exit velocity. A pusher mechanism, shown most clearly in FIGS. 14 and 15, comprises an upstanding pusher plate 398 adapted for horizontal sliding travel in each of spaced-apart guide tracks 400 from the retracted position illustrated to an extended position, not shown, by means of double-acting hydraulic piston-cylinder assembly 402, FIG. 15, having piston rod 404, to engage the deposits and to positively assist the travel and discharge of deposits 326 between the opposed sets of wheels 380, 382. It will be understood that modifications can be made in the embodiment of the invention illustrated and described herein without departing from the scope and purview of the invention as defined by the appended claims.

A method and apparatus for conveying and stripping electro-deposited metal sheets from cathode plates. A plurality of stations including a feed station, initial horizontal parting station, main vertical stripping station, replacement station, and discharge station are sequentially arranged within the stripping apparatus and cathode plates having metal sheet deposits thereon are conveyed through the apparatus by means of a reciprocating transfer carriage in combination with supporting slide bars and indexing means. Metal sheet deposits are stripped in a fast, simple and efficient manner by using closed entry horizontal knives to effect initial parting of each deposit and vertical stripping knives to remove the deposits from the two sides of the cathode plate without clamping of the cathode plate while controlling cathode plate sway. Liberated metal sheets are quickly removed from the apparatus and stripped cathode plates are conveyed from the apparatus at a discharge station.

BACKGROUND OF THE INVENTION The present invention relates to a vocal game apparatus for playing a game using recorded voices, and more particularly, to a game in which the players record the voices to be used. Apparatuses are known for playing a game, etc. using recorded voices. That is, a player listens to a voice reproduced from a recording medium and performs a predetermined operation in accordance with an instruction related to the sounded voice. However, in such conventional vocal game apparatuses, since the voices are fixedly prerecorded and messages reproduced during the game remain unchanged, there is a problem in that they cannot create in the player who is familiar with such a game a continuous interest in that game. SUMMARY OF THE INVENTION With the above-described problem in mind, it is an object of the present invention to provide a vocal game apparatus which gives players the opportunity to record arbitrarily their own messages, also which reproduces the plurality of voiced messages or words in accordance with predetermined game contents, and in which a player competes (with other players or himself) for scores using the recorded messages or words and indications of lights. To achieve the foregoing and other objects of the present invention and in accordance with the purpose of the invention, there is provided a vocal game apparatus, including: a plurality of input switches operated by one or a plurality of players; recording and reproducing means for recording voiced messages or words onto a recording medium at locations corresponding to respective input switches and reproducing the contents of the recording medium in response to a reproduce command; a plurality of lighting indication means, one corresponding to each input switch; and control means for receiving signals derived from said input switches and outputting signals to control operations of said recording and reproducing means and said lighting indication means, said control means in a first game operation lighting said lighting indication means at the same time when the words or messages from said recording and reproducing means are reproduced, and when the player operates one of the input switches (or the switch corresponding to himself in a multi-player game) when the reproduced message corresponds to and is coincident with the lighting of that lighting indication means, recording a score for the player. In a second game operation said control means controls the reproducing means to reproduce a sequence of the words or messages, and immediately following when the player operates the input switches in an order corresponding to the order of the produced sequence, the player scores a point and the process repeats with one additional word or message added to the sequence, until the player fails to correctly operate the input switches. These together with other objects and advantages of the invention will become more apparent from the following description, reference being had to the accompanying drawings wherein like reference numerals designate the same or similar parts throughout. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the game apparatus of the preferred embodiment according to the present invention; FIG. 2 shows the mounting portion of input switch keys used in the present invention shown in FIG. 1; FIG. 3 is a side, cross-sectional view of one of the input switch keys shown in FIG. 1; FIG. 4 is a circuit diagram showing an embodiment of circuitry of the game apparatus shown in FIG. 1; and FIGS. 5, 5A, 6, 7, 7A, 8, 8A, 9, 10, 10A, 11, 12, and 12A are flowcharts indicating processing procedures for the game apparatus according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, preferred embodiments will be described with reference to the attached drawings. FIG. 1 illustrates one preferred embodiment according to the present invention. The vocal game apparatus is provided with a disk-shaped casing 1 from which four cylindrical convex portions 6 spaced 90° apart are projected in its radial direction. On the upper surface of the casing 1 are arranged an on/off switch 2, a reset switch 3, a recording microphone 4, and an output surface 5 of a speaker (FIG. 4) housed within the casing 1. In addition, a circular opening 6A is provided on the upper surface of each cylindrical convex portion 6. A cylindrical input switch key 7 is disposed, enabled to move up-and-down, within each opening 6A and projecting above each opening 6A. At least the upper parts of the four input switch keys 7 are made of transparent materials, and each switch key 7 is a different color. For clarity of description, starting from the upper left side of the apparatus in FIG. 1, the switch keys 7 are red, blue, yellow and green sequentially in clockwise direction as viewed from FIG. 1. Hence, when the four colored switch keys 7 are identified in the later description, they are referred to as color keys 7R (red), 7B (blue), 7Y (yellow) and 7G (green). As shown in FIG. 2 and FIG. 3, each input key 7 is provided with an extended portion 8 extending from the lower part of the side surface of each key 7 toward the main body of the apparatus. A tip end of the extended portion 8 is integrally provided perpendicularly with a cylindrical shaft 9. Each switch key 7 is mounted within the casing 1 in each opening 6A so as to enable a pivotal movement in the up-and-down direction, with a shaft 9 pivotally grasped between two sets of up and down journal plates 10a, 10b installed on an upper plate 1a and a bottom plate 1b of the casing 1. Each switch key 7 is held in the position shown in the drawing by means of a switch piece 11 comprising a flexible metal plate bent so as to contact with a lower surface of the extended part 8, rising from the bottom plate 1b of the casing 1. A tip portion 11a of the switch piece 11 is bent downward and another switch piece 12 is fixed so as to face the tip portion 11a. The two switch pieces 11 and 12 are normally in a non-contact "off" position, held apart by means of an elastic force of the upper switch piece 11. However, if a player pushes down on an upper surface of any switch key 7, the tip 11a of the switch piece 11 contacts the switch piece 12, signalling an input. Each input switch is constructed in this way. An electric lamp 13 is arranged as lighting indication means inside each input switch key 7. A circuit 30 shown in FIG. 4 is housed within the casing 1. FIG. 4 schematically shows the reset switch 3 of FIG. 1, input switches 14R, 14B, 14Y and 14G (comprising switch pieces 11 and 12 corresponding to the four color keys 7R, 7B, 7Y and 7G as described above), the electric lamps 13 housed within respective color keys 7R, 7B, 7Y and 7G, a recording and reproducing large scale integration (LSI) chip 16 (which is readily available, manufactured by the Toshiba Corporation, Product No. T6668-BS) and semiconductor memory (RAM) 17 which records voiced messages or words corresponding to the respective input switches 14R, 14B, 14Y and 14G and reproduces the messages or words in response to a reproduce command. These elements are connected to a one-chip microcomputer (CPU) 15 (also readily available, Matsushita Electronic Corp. Product No. MN15543NTV) which serves as control means for the vocal game apparatus. The recording and reproducing LSI 16 is connected to the recording microphone 4 and to the speaker 19 via an amplifier 18. It is noted that this circuit uses four batteries 20 as a power supply and its voltage (6V) is supplied to the circuit via the on/off switch 2. The recording and reproducing LSI 16 stores in the RAM 17 the voiced messages or words inputted into the microphone 4 corresponding to the input switches 14R, 14B, 14Y and 14G during a recording process. Vocal data is fetched from the RAM 17 at random, outputted as a vocal signal, and sent to the speaker 19 via the amplifier 18 in order to reproduce it. Next, a game action according to the preferred embodiment will be described. First, this embodiment is such that the players record a message or sound corresponding to each one of the four color keys 7R, 7B, 7Y or 7G and each of the one to four players selects one of the color keys 7R, 7B, 7Y or 7G as his or her home position. During a game selection stage, a match game selected by pushing the red color key 7R and the memory game is selected by pushing the blue color key 7B. In the match game, each of the one to four players selects one of the color keys 7R, 7B, 7Y or 7G as described above as his home position. In the one player only memory game, the apparatus automatically designates the red color key 7R as the player's home position. After the game is finished, scores can be confirmed by voice and light indications. In the game referred to as the match game, voiced messages or words prerecorded by the players corresponding to the four color keys 7R, 7B, 7Y and 7G are reproduced at random by the game apparatus, and simultaneously the electric lamp 13 of one color key is turned on at random. When the reproduced voice corresponds to the lighted color key and a player pushes that color key, the apparatus adds a point to the score for that player. The score calculation is such that one point is added to the player's score whenever one correct key is operated and one point is subtracted when the player incorrectly pushes a color key 7 or fails to push the correct corresponding key within a predetermined period of time. On the other hand, in the memory game the apparatus sequentially specifies at first three color keys from among the four color keys 7R, 7B, 7Y and 7G through their corresponding prerecorded voiced messages or words. A score is obtained when the player enters the specified color key sequence in the same order as specified by the reproduced voices. This is referred to as a player repeat. After each score, the length of the specified color keys sequence is increased by one. The game is over when the player fails to enter the sequence in the proper order, the sequence is not entered within a certain period of time (for example, 10 seconds), or the length of the specified color key sequence has reached an upper limit (for example, 32). Hereinafter, an operation and game procedure required for carrying out the above-described games will be described with reference to the flowchart shown in FIG. 5-FIG. 12. First, as shown in FIG. 5, when the on/off switch 2 is turned on, the game apparatus enters a record enable state. In this embodiment, to make a 8-word record for the voice, the CPU 15 first clears a word number counter as shown in FIG. 6, next illuminates in a loop form mode the four color keys 7R, 7B, 7Y and 7G in this order to command the player to record and produces a repeating sound such as "PI", "PI". At this time, the CPU starts a timer defining an illumination time of each color key. Then, the CPU 15 sends a record command to the recording and reproducing LSI 16 to wait for the voice input. When a color key is illuminated and the player voices a word, a recording corresponding to that color key is carried out. That is to say, the voice of the player is inputted from the microphone 4 and is stored in a predetermined memory location of the RAM 17 as the vocal data by means of the recording and reproducing LSI 16. It should be noted that since the voice stored in the RAM 17 is within one second per word, the CPU checks to see whether one second has elapsed whenever the voice is inputted and thereafter counts the word number. In addition, since the voice to be recorded is used in the above-described two kinds of games, the first four words of the eight words specifies a name of each color key 7R, 7B, 7Y and 7G (for example, name of each player) and the subsequent four words specifies a color designation or other type of player specified word code for each color key 7R, 7B, 7Y and 7G (for example, red, blue, yellow, green). When the above-described recording is completed, the game apparatus enters a game selection mode and the CPU 15 lights the four color keys 7R, 7B, 7Y and 7G sequentially a predetermined number of times in this order in a loop lighting form. At this time, when a player depresses the red color key 7R or blue color key 7B, the above-described match game or memory game is selected. In addition, when the yellow color key 7Y is depressed, the apparatus returns to the record enable state and can record messages corresponding to each color key again. In this way, the yellow color key 7Y has a function as a reset key. When the red color key 7R is depressed during the above-described loop lighting mode, the match game is selected, and a player registration procedure follows. This procedure starts with a generation of such a repetition sound as "PI", "PI" as shown in FIG. 7. If the player sequentially depresses each color key 7R, 7B, 7Y and 7G within a predetermined period of time (for example, four seconds after either of the color keys is depressed), the corresponding light is turned on and the number of players and positions are registered. For example, if the number of players is three (suppose that the three players are A, B, and C) and A depresses the red key 7R, B depresses the blue key 7B and C depressed the yellow key 7Y, these color keys function as operation keys and home position for the respective players. Then, after a start melody, the match game begins. On the other hand, when the blue key 7B is depressed during the above described loop lighting mode, the memory game is selected, and the above-described player registration is omitted. With the red color key 7R being automatically selected as a home position, the game is continued in accordance with procedures shown in the flowcharts of FIG. 10 and FIG. 11. Upon completion of the match game or the memory game, if the red or blue color key 7R or 7B is depressed, the apparatus returns to a start state of the corresponding game. When the yellow color key 7Y is depressed, the apparatus again lights on each color key in the loop lighting mode for recording messages for each switch key 7. In addition, when the green color key 7G is depressed, the score of the last game is reconfirmed in accordance with procedures shown in the flowchart of FIG. 7 to be described later. Next, a further detailed description of the match game will be described with reference to FIG. 8. As described above, when the match game is selected and player registration is completed, the beginning of the game is signaled by the playing of a start melody. The CPU 15 selects one of the following two procedures according to the number of players based on the number of players registering, i.e., depending on whether the number of players is one or two to four. The Match Game for One Player First, the sole player is preset to have ten scores. This is because the score is decremented by one whenever the player makes a mistake (fails to press the appropriate color key at the proper time or presses the wrong key at any time), and the game is over when he makes ten such errors. During the game, processing is carried out as to slowly change the time interval between each set of lighting and issuing sound, i.e., the time interval from the lighting of the subsequent color key and the producing of the subsequent voice in order to make the game gradually more difficult by shortening the length of time between the lighting and sound sets by a predetermined time (for example, 10 msec.) whenever the voice is once produced regardless of the score. The four different voiced messages which have been recorded (for example, names of the respective color keys) are produced at random at the time intervals set in the above-described processing and the lights of the respective color keys are turned on at the same timings at random until the game is over. These lighting and sound producing operations are executed on the basis of random numbers ranging from zero to n generated in the CPU 15. The lighting and sound producing operations shown in FIG. 9 will be described hereinbelow. Although the numbers from zero to n (n denotes a natural number) are produced at random, n is different depending on whether the number of players is one or two to four. For example, when the number of players is one n=15, and when the number of players are two to four n=8. Depending on the number generated during the random processing, whether or not to match the recorded message to the color key being lit is determined. In detail, if the random number is greater than five, the color key being lit is not matched with its corresponding message and one of the messages which does not correspond to the color key being lit is outputted. If the random number is equal to or less than five, a coincidence flag of the CPU 15 is set to 1. If the random number is equal to or less than three, the color key which has been lighted the least number of times is lighted and the voice corresponding to the lighted color is produced, and a percentage of selection for the lighted color keys is adjusted. That is, the overall percentage that this particular color key has been lighted is adjusted upward, and the percentage of lightings for the other keys is adjusted downward. Furthermore, if the random number is neither equal to nor less than three (the random number is four or five), the message corresponding to the randomly lighted color key is produced. In this way, a probability of matching the lighting of the color keys with its respective word is 6/n in the lighting and sound producing operations. As described above, n is different depending on whether the number of players is one or two to four. This is because in the case where the number of players is two to four, each player may perform a key operation only if the lighting of the color keys at his own home position is matched with the message. A probability that the lighting of the color key is matched with the message for each player becomes less than 6/n. Hence, the above-described n in the case of one player is set larger than that in the case of two to four players to adjust the percentage of selection, thus guaranteeing approximately the same degree of player participation in both the 1 and 2-4 player games. When the one player depresses a color key which is lighted and the reproduced voice corresponds to that color key, the player scores a point. For example, when the blue color key 7B is lighted and the word corresponding to the blue color key 7B is reproduced, the player gets one point if he depresses blue color key 7B. On the other hand, if he depresses a color key different than the lighted color key when a lighted key/reproduced voice match occurs, or depresses any color key when no lighted key/reproduced voice match occurs, or does not depress the lighted color key when a lighted color key/reproduced voice match occurs, one point is decreased from the total running score. At the same time, one point is decremented from the permissible failure score (which was originally preset at ten). When one player is playing and the number of times the player fails reaches ten, the game ends. The final score is then indicated after a predetermined melody is sounded. The game will also end when the number of times the above-described voice producing and lighting operations has reached a predetermined number (e.g., 400 times) even if the number of times the player has failed has not reached ten. The total score indication is carried out in accordance with the flowchart shown in FIG. 12. First, a score melody is produced and the CPU determines whether the number of players is one. Then, for one player, the score is calculated and the score indication is carried out in such a way that the tens digit of the score is indicated by the number of times the color key chosen by the player for his home position is turned on for one second, and the units digit of the score is indicated by the number of times the same color key is turned on for 0.3 seconds. For example, when the color key specified by the player is the red color key 7R and his score is 25, the lighting of the light of the red color key 7R is repeated two times for one second and is repeated five times for 0.3 seconds. In addition, the repeating sounds such as "PI", "PI" are produced at the same time as the above-described lighting repetitions. Thereafter, although a predetermined fanfare sound is produced at the end of first game even when the preset score is further subtracted and the total score becomes a negative number, at the end of second and subsequent games the score of that game is compared with the highest score of previous like games during the same session (since the apparatus was turned on). If the present score is greater than the previous high score, a fanfare sound is produced. If the present score is less, such a sound as "bu" is produced. After the score is indicated, if the same game is to be played again, the player depresses the red or blue color key 7R or 7B. In a case when the different game (in this case, the memory game) or when the match game is to be played with the different number of players, the yellow color key 7Y is depressed. At this time, the routine returns to (2) in FIG. 5, the lights are in the loop lighting mode, and the new game can be selected. At this time, if the red or blue color key is depressed, the corresponding game is selected. In addition, if the score in the previous game is to be reconfirmed, the green color key 7G is depressed. The Match Game for Two to Four Players As shown in FIG. 8, the players' scores are not preset at 10, and the processing that determines the time interval of the lighting and sound producing procedure is changed to vary the difficulty of the game. Then, the four voiced words (for example, names of the respective players) which have been recorded are produced at time intervals defined at the above-described processing and simultaneously the light of a color key is turned on. This lighting and sound producing operations are the same as those in the case when the number of players is one, except the value of the random number for determining whether to output a match is different (n=8). However, in the case of two to four players, a four-person check is carried out whenever one lighting and sound producing operation is carried out. This is a check to see sequentially whether a key operation is correct for a color key to which the above-described player registation is performed. At this time, each player gets one score by depressing his color key at a time interval in which his color key lights and the sound produced corresponds to his color key (which he chose when the player registration was carried out). On the other hand, if the player fails to depress his color key when it is lighted and the corresponding voice is reproduced or if the player depresses his color key when there is no match, the player's score is decreased by one. When the game starts the time interval between consecutive lighting and sound producing operations is set to one second. The time interval decreases by a predetermined period of time (for example, 8 milliseconds) whenever a lighting and sound producing operation is carried out. When the time interval reaches below a predetermined period of time (for example, 0.5 seconds), the subtraction value is reduced (for example, to 2 msec.). Thereafter, when the time interval has reached a predetermined lower limit time (for example, 0.3 seconds), the lighting and sound producing operations are subsequently repeated at the lower limit time interval. Although the game for the two to four players is played in this way, the game is over when the time interval between consecutive lighting and sound producing operations has reached a predetermined value (for example, 0.4 seconds) and thereafter all players make an error. After a predetermined melody is produced, the scores are displayed. The score display procedure is such that a score melody is first produced as shown in the flowchart of FIG. 12. Next, the score of each player is indicated. The electric lamp 13 of the color key of each player is turned on repeatedly for 0.3 seconds and a simultaneous "PI" is sounded. Each coinciding flash and "PI" sound represents a point scored by the players, and simultaneously with each flash and "PI" sound one point is decremented from each players' score. When the score of the player who had accumulated the least number of points reaches zero, the flashing and sounding cease, a "bu" sound is produced and the apparatus indicates the identity of the last placed player by producing the word or message corresponding to his home position. This process is repeated for the remaining players, until only the player who accumulated the most points remains. When his score is finally decremented to zero, a fanfare is sounded and that player is identified as described above. The operation following the end of the game for two to four players is the same as that in the one player game. The Memory Game Next, the memory game will be described with reference to FIG. 10 and FIG. 11. When the memory game is selected by depressing the blue key 7B during the above-described loop lighting mode, a one player game automatically begins with the red color key 7R as the player's home position. First, a start melody is rung and three color keys are sequentially designated (the same key may be specified twice). Then, the CPU 15 adds one to a value of a specified number counter CNT1, which is set at an initialization state to two (2), resulting in three (3) being stored in CNT1. Thereafter, the counter is incremented by one after each successful player response, which is described below. When the value reaches an upper limit (e.g., 32), the game ends. In addition, in this game, this counting corresponds to the increasing length of the color key sequence, in which a newly selected color is added after the last specified color of the preceding sequence. Therefore, initially, with the last color selected sequentially, one is added to a value of a color specification counter CNT2, set to (-1) at the initialization state, to give zero. Thereafter, one is added thereto whenever a color is specified and output by the reproducing means. When the value of the counter CNT2 is matched with the value of the specified number counter CNT1, a "player repeat" is carried out. Since at first three prerecorded words corresponding to the color keys, such as red, blue and green, are sequentially sounded, the player depresses those color keys in that order. When this "player repeat" is correctly carried out within a predetermined time, a repeating sound such as "PI", "PI" is produced and one point is awarded to the player. Next, the game apparatus reproduces the above word sequence again and adds a new word following the above-described sequence, so as to now specify four colors, and waits for the "player repeat". Upon a successful player repeat, again the repeating "PI" sound is produced and the player is awarded another point. A new color is added to the end of the specified color sequence just repeated by the player. In this way the sequence length grows until one of two events occurs. If the player fails to repeat the sequence properly or the sequence reaches a predetermined maximum length (for example, 32), then the game ends. In the first case, the game apparatus produces a "bu" sound, the score melody is sounded, and the score is displayed. In the second case, when the player correctly repeats the sequences until the predetermined maximum sequence length is reached, the score melody is sounded and the score display procedure operates in the same way as in the match game. Alternate Embodiment In an alternate embodiment for the present invention, the procedures for playing the match game and the memory game are slightly different. The differences between this alternate embodiment and the above-described embodiment are found in the flowcharts 5A, 7A, 8A, 10A and 12A, which take the place of flowcharts 5, 7, 8, 10 and 12 of the above-described embodiment respectively in the case of this alternate embodiment. As per FIG. 5A, the first step of the second embodiment is the recording of the voices. In this embodiment, only four words or voiced messages are recorded, one corresponding to each of the color keys 7R, 7B, 7Y and 7G. After the recording is completed, the red and blue color keys 7R and 7B alternately turn on. If the red input key 7R is pressed, the match game has been chosen and a player registration as per the flowchart of FIG. 7A is begun. The only difference between this player registration and the player registration of first embodiment is that the lights alternately turn on around the loop upon the choosing of the red color key 7R, representing that the player registration stage has been entered. The differences between playing the match game of the second embodiment as opposed to that of the first embodiment are found in the flowchart of FIG. 8A. In the alternate embodiment, the game ends when the score of any one of the players reaches 100. Differences also exist between the memory game of the alternate embodiment and the memory game of the first embodiment. In the alternate embodiment, the sequence length limit is 100 rather than the 32 of the first embodiment. That is, upon a successful player repeat of a 100 word sequence, the highest score possible has been achieved and the game ends. Also, as seen from the flowchart in FIG. 10A, a score display step has become part of the memory game procedure. A special memory game display score step has been added, as shown in FIG. 12A. When the one player memory game has been completed, the longest sequence successfully completed by the player is reproduced by the game apparatus. During this playback, both the color key is lit and the corresponding voice reproduced for each step of the sequence. If the sequence that has been successfully reproduced is the longest reproduced so far during a given playing session, a fanfare is sounded upon completion of the repeat by the apparatus. If it is not the best score during a given session so far, a "bu" sound is reproduced. Upon completion of either the memory game or the match game, the game selection mode begins again. Once again, the red and blue color keys 7R, 7B are lighted alternately. At this point, if the red color key is pressed, the match game procedure begins again; if the blue color key 7B is pressed, the memory game procedure begins again. As per the flowchart of FIG. 5A, another difference over the first embodiment is illustrated. If the yellow key is pressed at this point, each color key is lighted once going around the loop, and at the same time as the lighting, the recorded word corresponding to that color key is reproduced, thus confirming the recorded voices. If the green color key 7G is pressed, the score for the last game played is once again displayed. After either the step of confirming the recorded voices or displaying the score of the last game, the procedure returns to the step of alternately lighting color keys 7R and 7B. Although the preferred embodiments have been described hereinabove, the present invention is not limited to these embodiments. For example, although the input switch keys are identified by colors, they may be identified by their profiles and so one. In addition, the game which carries out the plural kinds of voices which have been recorded and lights are not limited to the kinds of games in the preferred embodiments and many kinds of games can be conceived. As described hereinabove, since according to the present invention the game can be played in such a way that the players arbitrarily record their own messages, play back the several kinds of voices which have been recorded in accordance with the predetermined procedures, and compete with each other to make scores, the vocal game apparatus can be devised such that even a skilled player does not easily tire of playing.

A vocal game apparatus records arbitrary sounds and messages from game players. These recorded sounds correspond to input switches, which are different colors and contain a lamp for lighting. Players respond to the reproduced player recorded messages and the lighting of the lamps of the input switches in playing any of a plurality of games, all of which use the messages and light in some form, stored in memory of the vocal game apparatus. In a match game, the players must hit an input key in response to a match of a reproduced player message and lighting of a lamp of an input key. In a memory game, a player must correctly repeat a sequence of the colored input keys voiced by the vocal game apparatus by hitting the corresponding input keys in the proper order. The recorded messages may be changed as often as the players desire, thus giving the players a continuous interest in the vocal game apparatus.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates generally to the field of error correction in bandwidth limited communications systems. More particularly, the invention provides a Frequency Mapping Coding (FMC) scheme for varying the application of error correction redundancy to the transmitted data based on the channel transmission characteristics. [0003] 2. Description of Related Art [0004] For bandwidth limited communications environments, such as digital subscriber lines (DSL), characteristics such as the signal to noise ratio (SNR) are not uniform over the useable bandwidth for communication and are typically not even symmetrical. The SNR in the low frequency range, about 1 MHz or below, is much better than in the higher frequency range from 1 MHz to 10 MHz. Traditional quadrature amplitude modulation (QAM) communication systems are designed to work at a symmetric and relatively flat SNR characteristics and, therefore, cannot fully make use of the SNR characteristics over the entire bandwidth. Selection of a QAM scheme is therefore typically limited by the minimum SNR in the available spectrum and those portions of the spectrum having worse SNR characteristics cannot be fully used. [0005] A common alternative solution to overcome the varying SNR over the spectrum is the use of digital multi tone modulation (DMT). In this solution, the modulated signal is divided into different tones spread over the spectrum and a different number of bits is assigned to each tone. The SNR characteristics in the different portions of the spectrum are better utilized. However, the complexity and cost associated with DMT schemes, both to implement and manage, can be significantly higher than QAM approaches. A DSL communication system employing DMT has much higher implementation complexity than a DSL with QAM. Additionally, the spectrum is not really fully used in DMT schemes, since some guard band is needed to separate the adjacent tones. [0006] It is therefore desirable to employ QAM to avoid the complexity associated with DMT, however, correct for the channel characteristics where SNR may impact signal fidelity. SUMMARY OF THE INVENTION [0007] A Frequency Mapped Coding (FMC) scheme is employed to vary the error correction redundancy provided in the communications signal based on the channel characteristics for IQ based modulation. Additional redundancy is added to the coding of the signal in portions of the spectrum where SNR is low and reduced redundancy in the high SNR portions of the spectrum. The matching of the channel spectral characteristics by the FMC combined with the “analog” nature of an exemplary QAM modulation, more smoothly fits the available spectrum for better use of the channel capacity. The increased redundancy coding reduces the theoretical bit rate of the QAM channel however the constant bit error rate (BER) is maintained. [0008] Trajectories or differential positions rather than the positions of the signal in the constellation are used to measure the degree of vulnerability and add redundancy. The more vulnerable the trajectory is, the more redundancy is added, i.e. less information is transmitted. BRIEF DESCRIPTION OF THE DRAWINGS [0009] These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: [0010] [0010]FIG. 1 is a Power Spectral Density (PSD) plot for the transmission QAM signal with the channel characteristics overlaid on the signal; [0011] [0011]FIG. 2 is a PSD of the Receiving QAM signal; [0012] [0012]FIG. 3 is a plot of the PSD of FIG. 2 with the degree of damage to the QAM signal overlaid; [0013] [0013]FIG. 4 is a constellation diagram for a simplified embodiment of the invention for use with Differential Quaternary Pulse Shift Keying (DQPSK) demonstrating the modulation transition trajectories in the constellation of the DQPSK modulation; [0014] [0014]FIG. 5 shows the frequency spectrum for the trajectories shown in FIG. 5; [0015] [0015]FIG. 6 is an exemplary vulnerability table for the DQPSK modulation trajectories of FIG. 5; [0016] [0016]FIG. 7 is an exemplary bit stream for the DQPSK modulation with redundancy addition through a delay mechanism; [0017] [0017]FIG. 8 is a table of the input words, mapping bits and resulting decoding for the example of FIG. 8; [0018] [0018]FIG. 9 is a block diagram of the elements of the system employing the present invention for transmitting and receiving data; [0019] [0019]FIG. 10 is a schematic block diagram of the FMC elements for the DQPSK exemplary embodiment of FIGS. 4 - 9 ; [0020] [0020]FIG. 11 a schematic block diagram of the FMC decoder elements for the DQPSK receiver corresponding to the transmitter FMC elements disclosed in FIG. 10; [0021] [0021]FIG. 12 is a flow chart of an exemplary initialization and training sequence for a system employing the FMC architecture; [0022] [0022]FIG. 13 is a schematic block diagram of the system elements for performing the exemplary sequence of FIG. 11; and, [0023] [0023]FIG. 14 is a graphical estimation of the BER based on SNR with exemplary Reed Solomon coding only, Trellis Coding and RS coding using the FMC of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0024] For the purposes of description of an embodiment of the invention, a QAM system is employed, however, the invention is applicable to other orthogonal component based modulation in general. Referring to the drawings, FIGS. 1 and 2 demonstrate the distortion of the QAM PSD from the transmitted signal PSD 2 to the received signal PSD 4 based on the channel characteristics 6 . FIG. 3 demonstrates graphically the relative degree of damage 8 to the QAM signal that is caused by the characteristic of the channel. This graphical depiction indicates where and to what degree redundancy should be added for error correction of the signal. FIG. 4 shows the trajectory of the signal in the constellation while FIG. 5 shows the related spectral components resulting from those trajectories. Trajectories 10 in the lower right quadrant of FIG. 4 result in a first frequency “FREQ 0 ”. A counter-clockwise trajectory 12 results in a second frequency “FREQ 1 ” while a clockwise trajectory 14 results in a third frequency “FREQ 2 ”. As seen in FIG. 5, the response 16 at FREQ 0 falls within a portion of the PSD where only moderate damage to the signal would be anticipated. Similarly, the response 18 at FREQ 1 falls in the spectrum with little likely damage due to the channel characteristic. However, the response 19 at FREQ 2 falls in a portion of the spectrum where high damage vulnerability is present. It can be seen that different signals will generate different spectral components and therefore different degrees of damage can be caused. [0025] Continuing the DQPSK modulation example, FIG. 6 is an exemplary table demonstrating a portion of the vulnerabilities for possible trajectories. This table corresponds to the graphical depiction of FIGS. 4 and 5. For a sequence where the last sample offset was 0, the current offset is 0 and the next sample offset is 0, the relative damage or vulnerability has been defined as a “3” on a scale of 0 to 7 based on the anticipated frequency response of FREQ 0 . Similarly for a last sample offset of π/2, a current sample offset of π/2 and a next sample offset of π/2 a relative damage of 7 is established corresponding to the anticipated frequency response of FREQ 2 . A last sample offset of −π/2, a current sample offset of π/2 and a next sample offset of −π/2 shows a relative damage vulnerability of 0 based on the anticipated frequency response of FREQ 1 . Finally, a last sample offset of π, a current sample offset of π, and a next sample offset of π results in a relative damage assessment of 4. [0026] A bit stream for the DQPSK modulation example is shown in FIG. 7. As an example of FMC implementation for this model, to establish redundancy based on the trajectory of the bit transmission sequence, a two bit word or sample is assumed. As shown in the table of FIG. 8, input bits of the two bit words are mapped to define decoding for the bits. If a 1 is present in the first bit, only the first bit is decoded, as will be described in further detail subsequently. The FMC redundancy is added by creating a delay and outputting the second bit of the word a second time as the first bit of the next word. Using the examples of FIG. 7, the first two bits in the sequence are [0, 1] therefore, the first word for output is [0, 1]. The next bit in the sequence is a 1. The second word output is [1, 1]; however, since the first bit of the word is a 1, the second bit is repeated in the third word which is then [1, 0]. The third word, however, now has a 1 in the first bit, consequently, the second bit is again output as the first bit of the next word, resulting the in fourth word being [0, 0]. The convolutional encoder then encodes the sample for transmission in the standard fashion. [0027] The FMC scheme of the present invention can be characterized as a base-band error correction coding algorithm. Signal codes corresponding to higher frequencies in the spectrum have redundancy added for recovery of errors if loss occurs. The FMC scheme is also a bit allocation and management tool which is flexible if the channel characteristic changes. The FMC can adapt to achieve maximum throughput fully using the channel capacity. While similar to Multi-Dimension Trellis coding (MDTC) in the use of convolution coding and redundancy, the FMC scheme does not add the extra bits evenly or in a “color-blind” fashion. MDTC schemes are applied where frequency characteristics are always symmetrical. In the present FMC scheme, however, the unbalanced and unsymmetrical spectrum information of the channel characteristic provides the guide for selection and application of the redundancy coding. [0028] [0028]FIG. 9 shows the system implementation of the present invention in what effectively constitutes a concatenated code arrangement. In the transmitter 20 , the signal receives an outer encoding using Reed Solomon (RS) coding in the RS Coding block 22 followed by application of additional redundancy dependant on the signal frequency and channel characteristic, as described above, in the FMC block 24 . RS encoding and decoding are disclosed in the embodiments herein, however other Forward Error codes are equally applicable within the scheme. The inner coding scheme makes use of the convolution type coding to counteract the vulnerability due to the spectral deficiency. The transitional trajectories or the differential positions of the modulation dictates the spectrum that is used. As previously discussed with respect to FIGS. 7 and 8 for the simplified example, 2 bits or 1 bit can be mapped to each sample depending on whether the first bit is 0 or not. On the average the bit rate will be 1.5 bits/sample. [0029] [0029]FIG. 10 shows the FMC components for the exemplary DQPSK redundancy. The RS coded input signal 36 is provided to an input control circuit 38 as a bit stream for formation of 2 bit words or samples. If the first bit of the word created is a “1”, a halt signal 40 is generated by the input control circuit delaying input of the next bit for one clock cycle generated by the sample clock 42 . The second bit present in the input control circuit is provided to a delay buffer 44 and a normal output node 46 . The output control circuit 48 outputs the two bit word for encoding in the encoder 50 . If a halt single has been generated, the output control circuit will switch on the next clock cycle to the delay buffer node 52 to retrieve the bit stored in the delay buffer and output that bit a second time for modulation retrieving the next bit from the input control as the second bit of the word for modulation. [0030] Returning to FIG. 9, the signal is then modulated using QAM in the QAM block 26 . In the receiver 28 , the incoming signal is demodulated in the QAM block 30 followed by error checking with redundancy as defined by the FMC block 32 which accomplishes the decoding from the redundancy and encoding applied in FIG. 10 as shown in FIG. 11. The signal is then processed through normal RS decoding in RS coding block 34 . The FMC is used jointly with the Reed Solomon coding to reduce the error rate to a level where the RS coding can effectively be applied. Referring to FIG. 11, the FMC decoding for the exemplary embodiment shown employs a modified Viterbi decoder. The basic decoding of the incoming code is accomplished in decoder 54 , which for the exemplary 2 bit sample example results in a corresponding input bit length as in a normal Viterbi decoder. For decoding, the encoder memory also incorporates the vulnerability data present for the FMC application. As shown in FIG. 11, the incoming QAM modulated signal from the channel will be first delayed by the delay element or buffer 62 . The transitional trajectory or the differential positions will be detected by comparing the signals before and after the delayed elements. Such information is compared with the mapping tabled as defined in the vulnerability table. As the example shown in the exemplary DQPSK in FIGS. 7, 8 and 10 , when the clockwise trajectory is detected, it means one bit “1” is received. Otherwise two bits, starting with “0”, are received. The decoded data is subjected to rotation direction (trajectory) detection circuit 56 and output bit length control 58 to compensate for the redundancy added during the FMC encoding process. The trajectory detection circuit includes transitional trajectory decision and coding mapping information for feedback from the trajectory detection circuit to the decoder for decoding path development. [0031] Redundant data is placed in a first buffer 60 and second buffer 62 for comparison of last sample and next sample data for trajectory determination and matching of redundancy sets for reprocessing if required. The data is then provided on output 64 for Reed Solomon decoding as shown in FIG. 9. [0032] For a generalized case, the FMC redundancy approach is defined as described in the flow chart of FIG. 12. The transmitter and receiver of both the local and remote communications systems are initialized 100 . An initial narrow band communication is established with a bit rate much lower than the channel capability 102 to allow reduced error communication. The channel characteristic is analyzed over the whole spectrum and a vulnerability table is generated with a training sequence 104 . The vulnerability table is then exchanged between the local and remote systems 106 . Communications making use of the FMC is established at the operational channel bandwidth 108 . The variable length (added redundancy) convolutional coding created by the FMC is applied to transmitted and received signals by the local and remote system to fully employ the whole channel characteristic. [0033] [0033]FIG. 13 demonstrates an embodiment of the FMC coding block for a time domain implementation to generate the vulnerability table during the training sequence. A random signal is received in the buffer 110 and processed in the normal manner. A filter 112 with the channel characteristic, which may comprise transmission of the data over the channel itself, receives the data stream and provides the filtered data to one input of an exclusive-or (XOR) comparator 114 receiving the raw data stream from the encoder on the other input. The comparator output provides the control signal to the vulnerability table generator 116 also receiving the raw data stream at its input. If a segment of the data stream has a characteristic matching the channel filter, it will be filtered and no error output will be provided to the comparator. The data stream present on the other input to the comparator will pass the XOR function resulting in a control signal requiring no redundancy addition. If a segment of the data stream is not matched, the XOR function will not be satisfied and a vulnerability level will be added to the data. The redundancy logic of the FMC will add redundancy to the data stream based on the input data and vulnerability table created with a mapping code and resynchronize the data stream for output to the modulator as previously described with respect to FIGS. 4 - 10 . The time domain pattern in each data segment is retained and each pattern is transmitted to the receiver. Such patterns in the time domain are related to the frequency response of the channel. Each segment pattern can be used by the receiver to produce an original signal with different length, and therefore to achieve better error correction results. [0034] In the generalized case, the FMC receives a sample into a buffer corresponding to the input control circuit of FIG. 10. A comparison of the sample to the vulnerability table determines the redundancy to be added comparable to the one bit delay buffer of FIG. 10. [0035] For the FMC operation in the receiver, it is important to make use of the information in the information exchange stage as shown in FIG. 12. The FMC decoder obtains redundancy mapping code information and then applies error correction with different redundancy. As the result, different error correction capabilities are applied to different segments. [0036] The FIG. 14 depicts the simulated results with the FMC scheme of the present invention in conjunction with Reed-Solomon encoding in comparison with standard trellis coding and with RS encoding/decoding alone. The analytical result indicates about 2 dB improvement can be obtained. [0037] Having now described the invention in detail as required by the patent statutes, those skilled in the art will recognize modifications and substitutions to the specific embodiments disclosed herein. Such modifications are within the scope and intent of the present invention as defined in the following summary.

A Frequency Mapping Coding (FMC) scheme varies the application of error correction redundancy to transmitted data based on the channel transmission characteristics and the likelihood of error resulting from characteristics of the data stream being transmitted over the channel. The FMC is an error correction coding scheme making use of the non-linear feed-back mechanism and variable bit input step size to control redundancy applied. The FMC scheme accommodates the non-symmetrical nature of the SNR in bandwidth limited communications environments such as DSL to allow application of IQ based modulation, such as QAM, to these channels and is flexible for varying channel characteristics.

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims benefit of U.S. Provisional Application Serial No. 60/313,762, filed Aug. 20, 2001, entitled “Phasers-Compiler Related Inventions,” in the names of Liang T. Chen, Jeffrey Broughton, Derek Pappas, William Lam, Thomas M. McWilliams, Ihao Chen, Ankur Narang, Jeffrey Rubin, Earl T. Cohen, Michael Parkin, Ashley Saulsbury, and David R. Emberson. BACKGROUND OF INVENTION [0002] An error or “bug” in a computer program (i.e., executable source program) is one that causes the computer program to malfunction in some way. Debugging refers to the process in which the errors in the computer program are found and removed. Finding an error in a computer program running in a massively parallel processing (MPP) environment can be extremely difficult and time intensive. Before further discussing this problem, an overview of an MPP environment is provided using FIG. 1. [0003] MPP environments are computer environments that operate using a massive number of processors. It is typical for an MPP environment to use tens of thousands of processors. Each processor in such an environment is able to execute computer instructions at the same time, which results in a very powerful system because many calculations take place simultaneously. Such an environment is useful for a wide variety of purposes. One such purpose is for the software simulation of a hardware logic design. [0004] Large logic simulations are frequently executed on parallel or massively parallel computing systems. For example, parallel computing systems may be specifically designed parallel processing systems or a collection, referred to as a “farm,” of connected general purpose processing systems. FIG. 1 shows a block diagram of a typical parallel computing system ( 100 ) used to simulate an HDL logic design. Multiple processor arrays ( 112 a , 112 b , 112 n ) are available to simulate the HDL logic design. A host computer ( 116 ), with associated data store ( 117 ), controls a simulation of the logic design that executes on one or more of the processor arrays ( 112 a , 112 b , 112 n ) through an interconnect switch ( 118 ). The processor arrays ( 112 a , 112 b , 112 n ) may be a collection of processing elements or multiple general purpose processors. The interconnect switch ( 118 ) may be a specifically designed interconnect or a general purpose communication system, for example, an Ethernet network. [0005] A general purpose computer ( 120 ) with a human interface ( 122 ), such as a graphical user interface (GUI) or a command line interface, together with the host computer ( 116 ) support common functions of a simulation environment. These functions typically include an interactive display, modification of the simulation state, setting of execution breakpoints based on simulation times and states, use of test vectors files and trace files, use of HDL modules that execute on the host computer and are called from the processor arrays, check pointing and restoration of running simulations, the generation of value change dump files compatible with waveform analysis tools, and single execution of a clock cycle. [0006] The software simulation of a hardware logic design involves using a computer program to cause a computer system to behave in a manner that is analogous to the behavior of a physical hardware device. Software simulation of a hardware logic design is particularly beneficial because the actual manufacturing of a hardware device can be expensive. Software simulation allows the user to determine the efficacy of a hardware design. Software simulation of a hardware logic design is well-suited for use in an MPP environment because hardware normally performs many activities simultaneously. [0007] When simulating a hardware logic design in an MPP environment, or executing any other type of computer program in such an environment, debugging the program may become necessary. Properly performed debugging of the computer program reduces the probability of errors that could result in a malfunction. In the case of hardware logic design simulation, such an error might result in the eventual fabrication of computer hardware that does not work as expected. Such a malfunction is expensive and wasteful, so debugging plays an important role. [0008] One common method for debugging is to single-step the execution of the computer program. Each step represents an instruction executed on a processor of the computer. At each step, the state of the simulation system, including the variables and registers, is examined. By examining the state of the simulation system at each progressive step, the person debugging the program is able to inspect the program and determine precisely where the problem begins to manifest itself. Once this is known, the person is better able to correct the program and remove the bug. [0009] Another common method for debugging is to insert a breakpoint into the program so execution of the program stops at the inserted breakpoint. This is similar to single-stepping, but the breakpoint is used to specify a specific place to stop execution and examine the state of the simulation system. Breakpoints may normally be inserted at any instruction in a sequence of instructions. At the breakpoint, a determination may be made if there is a problem with the program at that point. By changing the breakpoint, the manifestation of the problem may be precisely found and can then be corrected. [0010] Single-stepping a program or performing a breakpoint in an environment where there are tens of thousands of parallel processors can be extremely difficult. In particular, MPP environments include a massive number of parallel processors, each executing instructions simultaneously. There is no effective way to synchronously halt a massive number of processors executing simultaneously. In particular, to halt all of the processors requires a global signal to be sent to all of the processors. The time the global signal takes to propagate through the system to reach each of the processors differs depending on the distance the signal has to travel. Thus, some of the processors in the system surpass the intended stopping point where the global signal attempted to stop the processors, which makes debugging impossible. Thus, clock skew and speed of light considerations prevent gated clocks and global control systems from being used. SUMMARY OF INVENTION [0011] In general, in one aspect, the invention relates to a method for performing debugging of an executable source program in a massively parallel processing environment. The method comprises associating a major cycle counter and a minor cycle counter with each of a plurality of execution processors in the massively parallel processing environment, obtaining a first stopping point value associated with the major cycle counter and a second stopping point value associated with the minor cycle counter, executing instructions of the executable source program on each of the plurality of execution processors, modifying the major cycle counter and the minor cycle counter, and halting each of the plurality of execution processors and returning control to the user if the major cycle counter reaches the first stopping point value and the minor cycle counter reaches the second stopping point value. [0012] In general, in one aspect, the invention relates to a method for performing debugging of an executable source program in a massively parallel processing environment. The method comprises associating a major cycle counter and a minor cycle counter with each of a plurality of execution processors in the massively parallel processing environment, obtaining a first stopping point value associated with the major cycle counter and a second stopping point value associated with the minor cycle counter, executing instructions of the executable source program on each of the plurality of execution processors, modifying the major cycle counter and the minor cycle counter, halting each of the plurality of execution processors and returning control to the user if the major cycle counter reaches the first stopping point value and the minor cycle counter reaches the second stopping point value, inspecting and modifying the executable source program, storing the first stopping point value in a memory register, storing the second stopping point value in a memory register, storing the major cycle counter in a memory register, and storing the minor cycle counter in a memory register. [0013] In general, in one aspect, the invention relates to an execution control system configured for a massively parallel processing environment. The execution control system comprises a major cycle counter and a minor cycle counter configured to be associated with each of a plurality of execution processors in the massively parallel processing environment, a memory register to store a first stopping point value associated with the major cycle counter, a memory register to store a second stopping point value associated with the minor cycle counter, and an executable source program. Each of the plurality of execution processors is halted and control is returned to the user to inspect and modify the executable source program if the first stopping point value is equal to the major cycle counter and second stopping point value is equal to the minor cycle counter. [0014] In general, in one aspect, the invention relates to an execution control system configured for a massively parallel processing environment. The execution control system comprises a major cycle counter and a minor cycle counter configured to be associated with each of a plurality of execution processors in the massively parallel processing environment, a memory register to store a first stopping point value associated with the major cycle counter, a memory register to store a second stopping point value associated with the minor cycle counter, an executable source program, a memory register to store the major cycle counter, and a memory register to store the minor cycle counter. Each of the plurality of execution processors is halted and control is returned to the user to inspect and modify the executable source program if the first stopping point value is equal to the major cycle counter and second stopping point value is equal to the minor cycle counter. [0015] In general, in one aspect, the invention relates to a computer system to perform debugging of an executable source program in a massively parallel processing environment. The computer system comprises a processor, a memory, and software instructions stored in the memory for enabling the computer system under control of the processor, to perform associating a major cycle counter and a minor cycle counter with each of a plurality of execution processors in the massively parallel processing environment, obtaining a first stopping point value associated with the major cycle counter and a second stopping point value associated with the minor cycle counter, executing instructions of the executable source program on each of the plurality of execution processors, modifying the major cycle counter and the minor cycle counter, and halting each of the plurality of execution processors and returning control to the user if the major cycle counter reaches the first stopping point value and the minor cycle counter reaches the second stopping point value. [0016] In general, in one aspect, the invention relates to an apparatus for performing debugging of an executable source program in a massively parallel processing environment. The apparatus comprises means for associating a major cycle counter and a minor cycle counter with each of a plurality of execution processors in the massively parallel processing environment, means for obtaining a first stopping point value associated with the major cycle counter and a second stopping point value associated with the minor cycle counter, means for executing instructions of the executable source program on each of the plurality of execution processors, means for modifying the major cycle counter and the minor cycle counter, and means for halting each of the plurality of execution processors and returning control to the user if the major cycle counter reaches the first stopping point value and the minor cycle counter reaches the second stopping point value. [0017] Other aspects and advantages of the invention will be apparent from the following description and the appended claims. BRIEF DESCRIPTION OF DRAWINGS [0018] [0018]FIG. 1 shows a typical parallel computer system. [0019] [0019]FIG. 2 shows a parallel computer system in accordance with one embodiment of the present invention. [0020] [0020]FIG. 3 shows a general purpose computer system. [0021] [0021]FIG. 4 shows a program memory of a processor that functions using major and minor cycles in accordance with one embodiment of the present invention. [0022] [0022]FIG. 5 shows debugging in an MPP environment in accordance with one embodiment of the present invention. [0023] [0023]FIG. 6 shows debugging in an MPP environment according to an embodiment of the present invention. [0024] [0024]FIG. 7 shows debugging in an MPP environment according to an embodiment of the present invention. [0025] [0025]FIG. 8 shows debugging in an MPP environment using breakpointing in accordance with one embodiment of the present invention. [0026] [0026]FIG. 9 shows debugging in an MPP environment using single-stepping in accordance with one embodiment of the present invention. DETAILED DESCRIPTION [0027] Specific embodiments of the invention will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. [0028] The present invention involves a method and apparatus for debugging in a massively parallel processing environment. In the following detailed description of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the invention. [0029] A computer execution environment and a class of simulation systems, e.g., multiple instruction, multiple data (MIMD), used with one or more embodiments of the invention is described in FIGS. 2 - 3 . In an embodiment of the present invention, the computer execution environment may use execution processors to execute execution processor code on a general purpose computer, such as a SPARC™ workstation produced by Sun Microsystems, Inc., or specialized hardware for performing cycle-based computations, e.g., a Phaser system. [0030] The system on which a compiled hardware design logic may be executed in one or embodiments of the invention is a massively parallel, cycle-based computing system. The system uses an array of execution processors arranged to perform cycle-based computations. One example of cycle-based computation is simulation of a cycle-based design written in a computer readable language, such as HDL (e.g., Verilog, etc.), or a high-level language (e.g., Occam, Modula, C, etc.). [0031] [0031]FIG. 2 shows exemplary elements of a massively parallel, cycle-based computing system ( 200 ), in accordance with one or more embodiments of the present invention. Cycle-based computation, such as a logic simulation on the system ( 200 ), involves one or more host computers ( 202 , 204 ) managing the logic simulation(s) executing on one or more system boards ( 220 a , 220 b , 220 n ). Each system board contains one or more Application Specific Integrated Circuits (ASIC). Each ASIC contains multiple execution processors. The host computers ( 202 , 204 ) may communicate with the system boards ( 220 a , 220 b , 220 n ) using one of several pathways. The host computers ( 202 , 204 ) include interface hardware and software as needed to manage a logic simulation. [0032] A high speed switch ( 210 ) connects the host computers ( 202 , 204 ) to the system boards ( 220 a , 220 b , 220 n ). The high speed switch ( 210 ) is used for loading and retrieval of state information from the execution processors located on ASICs on each of the system boards ( 220 a , 220 b , 220 n ). The connection between the host computers ( 202 , 204 ) and system boards ( 220 a , 220 b , 220 n ) also includes an Ethernet connection ( 203 ). The Ethernet connection ( 203 ) is used for service functions, such as loading a program and debugging. The system also includes a backplane ( 207 ). The backplane ( 207 ) allows the ASICs on one system board to communicate with the ASICs of another system board ( 220 a , 220 b , 220 n ) without having to communicate with an embedded controller located on each system board. Additional system boards may be added to the system by connecting more system boards to the backplane ( 207 ). [0033] In one or more embodiments of the present invention, the computer execution environment to perform evaluation of design nodes in a cycle-based, logic simulation system may be a general purpose computer, such as a SPARC™ workstation produced by Sun Microsystems, Inc. For example, as shown in FIG. 3, a typical general purpose computer ( 300 ) has a processor ( 302 ), associated memory ( 304 ), a storage device ( 306 ), and numerous other elements and functionalities typical to today's computers (not shown). The computer ( 300 ) has associated therewith input means such as a keyboard ( 308 ) and a mouse ( 310 ), although in an accessible environment these input means may take other forms. The computer ( 300 ) is also associated with an output device such as a display device ( 312 ), which may also take a different form in an accessible environment. The computer ( 300 ) is connected via a connection means ( 314 ) to a Wide Area Network (WAN) ( 316 ). The computer ( 300 ) may be interface with a massively parallel, cycle-based computing system described above and as shown in FIG. 2. [0034] The computer systems described above are for purposes of example only. An embodiment of the invention may be implemented in any type of computer system or programming or processing environment. [0035] The timing of an executing computer program is defined, in one or more embodiments of the present invention, in terms of major and minor cycles. A major cycle refers to a sequence of instructions that an execution processor is scheduled to execute. A minor cycle refers to each instruction that each execution processor executes at each clock cycle. The program memory of an execution processor that functions using major and minor cycles is shown in accordance with one embodiment of the present invention in FIG. 4. While executing, the execution processor executes instructions loaded into a program memory ( 400 ) until a last instruction ( 410 ) in the program memory is reached. Reaching the last instruction ( 410 ) causes the execution processor to return to an initial memory location ( 420 ). [0036] The transition from a current instruction ( 430 ) to a next instruction ( 440 ) is termed a minor cycle, and constitutes a single global execution clock cycle. Each execution processor in a MPP system typically has a similar memory and simultaneously executes one instruction in the program memory in each of the global execution clock cycles. The execution of the sequence of instructions from the initial instruction ( 420 ), through the remaining sequence of instructions, to the last instruction ( 410 ), and back to the initial position ( 420 ) is termed a major cycle ( 450 ). One skilled in the art will appreciate that an identical number of instructions are not required to be loaded into each execution processor's memory although the number of instructions is a pre-determined number. A final instruction may be inserted into shorter sequences to cause a particular execution processor to wait a specified number of clock cycles before returning to the initial position ( 420 ) and starting a new major cycle. [0037] In one embodiment, two counters are placed in each processor of the MPP system. The counters are termed a “major cycle” counter and a “minor cycle” counter. The major cycle counter changes value (increments or decrements) each time a major cycle is completed. The minor cycle counter changes value (increments or decrements) at each global execution clock cycle. A stopping point is defined by a major and minor cycle count. [0038] Embodiments of the present invention use a stopping point to debug the program that is executing in the MPP system. One embodiment is shown in FIG. 5. A stopping point value is specified in terms of major and minor cycles by a user (Step 500 ). The program begins executing, for instance, by each execution processor executing an instruction in the program memory (Step 510 ). The major and minor cycle counters are modified (Step 520 ). A determination is made whether the major and minor cycle counters are at the stopping point (Step 530 ). If not, the next instruction is executed (Step 540 ) and Step 520 repeats. If, however, the stopping point is reached (Step 530 ), then control is returned to the user and debugging is performed (Step 550 ). [0039] Another embodiment of the present invention is carried out using an architecture in each execution processor as shown in FIG. 6. An execution processor ( 600 ) includes a program memory ( 610 ) for storing instructions. A global execution clock ( 620 ) controls the timing that the execution processor ( 600 ) executes the instructions. At each oscillation of the clock ( 620 ), a next instruction in the program memory ( 610 ) is executed, creating a minor cycle ( 630 ). A major cycle ( 640 ) is reached when the system transitions between a final instruction 650 and a first instruction ( 660 ). [0040] A major cycle counter ( 670 ) and a minor cycle counter ( 680 ) are associated with the execution processor ( 600 ). On each minor cycle, the minor cycle counter ( 670 ) is adjusted. On each major cycle, the major cycle counter ( 680 ) is adjusted. The adjustment may include, incrementing or decrementing the counter. A register ( 690 ) is associated with the major cycle counter ( 670 ). A register ( 695 ) is associated with the minor cycle counter ( 680 ). The registers ( 690 , 695 ) may optionally be used to hold values associated with the major and minor cycle counters ( 670 , 680 ). For instance, at each adjustment of the major and minor cycle counters ( 670 , 680 ), the registers ( 690 , 695 ) may be set to decrement such that a defined stopping point occurs when the registers ( 690 , 695 ) have a value of zero. By examining the registers ( 690 , 695 ) periodically, a precise stopping point may be measured. [0041] An embodiment of the present invention that uses the above architecture is shown in FIG. 7. At Step 700 , the major and minor cycle counter registers in the execution processor are loaded with values corresponding to the stopping point. A determination is made whether the major and minor cycle counter registers are zero (Step 710 ). If so, the processor halts (Step 720 ) and debugging is performed (Step 730 ). [0042] Otherwise, a determination is made whether a new major cycle has initiated (Step 740 ). If so, the major cycle counter and major cycle counter register are adjusted (Step 750 ) and the next instruction is executed (Step 760 ). If, on the other hand, a new major cycle has not initiated (Step 740 ), a determination is made whether a new minor cycle has initiated (Step 770 ). If not, the system waits until a new minor cycle has initiated (Step 770 ). When Step 770 is true, the minor cycle counter along with associated register is adjusted (Step 780 ) and the process repeats until both registers reach zero (Step 710 ). At this point, the execution processor reaches the stopping point and halts synchronously with the other execution processors. [0043] A breakpoint process may be performed by defining a stopping point at a specific time value defined by major and minor cycles. Breakpointing, according to one embodiment of the present invention, is shown in FIG. 8. A stopping point is obtained from a user in terms of a value of major cycle and minor cycles (Step 800 ). The program begins executing, for instance, by each execution processor executing an instruction in the program memory (Step 810 ). The major and minor cycle counters are adjusted (Step 820 ). A determination is made whether the breakpoint is reached by examining the values in the major and minor cycle counters and comparing the value to the stopping point (Step 830 ). If the breakpoint has not been reached, the next instruction is executed (Step 840 ) and Step 820 repeats. If, however, the breakpoint is reached (Step 830 ), the execution processors halt synchronously with the other execution processors and debugging is performed (Step 850 ). [0044] A single-stepping of the program's execution may be performed by defining a stopping point every time the minor cycle counter changes value. To implement a single-step scheme, a machine state is checkpointed at a given major cycle. The major cycle counter and the minor cycle counter are loaded with the appropriate values for the stopping point. Single-stepping is implemented by returning to the checkpoint state and incrementing the value loaded into the major cycle and the minor cycle counters so that the machine state is one minor cycle beyond the previous stopping point. [0045] [0045]FIG. 9 is a flowchart showing virtual single-stepping in accordance with one embodiment of the invention. The major and minor cycle counters are loaded with the appropriate values for a checkpoint (Step 900 ). The machine state is checkpointed at a given major cycle. The system begins executing instructions and the cycle counters are adjusted (Step 910 ). A determination is made whether this is the time for the checkpoint (Step 920 ), if not, Step 910 repeats. When Step 920 is true, single-stepping is implemented by returning to the checkpoint state and incrementing the value loaded into the counters (Step 930 ) so that the machine state is one minor cycle beyond the previous stopping point. In this way, a “virtual” single-stepping is implemented without gated clocks. [0046] Advantages of the present invention include one or more of the following. The invention provides the advantage of placing two counters in each execution processor to define a stopping point to effectively and efficiently debug a hardware logic design program in a MPP environment. The invention provides the advantage of using a defined stopping point to debug allows gated clocks and global control systems to be used in the logic design and simulation system. Those skilled in the art appreciate that the present invention may include other advantages and features. [0047] While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.

A method for performing debugging of an executable source program in a massively parallel processing environment involves associating a major cycle counter and a minor cycle counter with each of a plurality of execution processors in the massively parallel processing environment, obtaining a first stopping point value associated with the major cycle counter and a second stopping point value associated with the minor cycle counter, executing instructions of the executable source program on each of the plurality of execution processors, modifying the major cycle counter and the minor cycle counter, and halting each of the plurality of execution processors and returning control to the user if the major cycle counter reaches the first stopping point value and the minor cycle counter reaches the second stopping point value.

TECHNICAL FIELD The present invention relates to technology for establishing communication connections between content providers that provide predetermined communication services and communication terminals that utilize these communication services. RELATED ART With the advancement of data communication technology, multiple types of communication networks (communication media) with different properties have been realized, such as communication networks that place emphasis on data transfer speed and response speed (in other words, communication networks in which high-speed data communication is possible), communication networks that place emphasis on security, communication networks in which usage fees are charged according to transfer data volume, communication networks in which flat-rate usage fees are charged regardless of transfer data volume, and so on. Furthermore, it has become possible for users requesting the utilization of various services offered by a content provider (hereinafter, “CP”) to select a communication network that has properties corresponding to the user's preference (e.g., attaching importance to data transfer speed, attaching importance to cost performance, etc.) from among multiple types of communication networks and to utilize services offered by the CP (e.g., JP-A-2005-39795 and JP-A-2006-60295). SUMMARY Incidentally, there also exists a need whereby the CP side providing various services via a communication network may wish to specify a communication network used for the utilization of that service beforehand in response to the service content. As stated above, according to an aspect of the technology disclosed in JP-A-2005-39795 and JP-A-2006-60295, it is possible to respond to needs on the user side, but it is not possible to respond to needs on the CP side regardless of whether the communication network that a user requests for utilization coincides with the communication network that the CP side requests. The present invention has been devised in consideration of the above issues with the purpose of providing technology for establishing a communication connection via communication media selected with consideration of both the content provider demand and the user demand between a content server that provides a predetermined communication service and a communication terminal that utilizes the communication services thereof. To resolve the above issues, according to an aspect of the invention, there is provided a communication terminal including: a property management table in which an appraised value of each of a plurality of types of communication media is registered for each of a plurality of predetermined items that shows communication media properties; a first priority ranking list in which a priority ranking assigned by users for each of the plurality of items is registered; a second priority ranking list in which a priority ranking assigned by a provider of the application program for each of the plurality of items is registered; selecting means for selecting one communication medium from among the plurality of types of communication media in response to the results of an addition, wherein in the event that a commencement of communication is specified according to a predetermined application program, for each of the plurality of types of communication media, a first weighting granted for an item in response to a priority ranking registered in the first priority ranking list and a second weighting granted for the item in response to a priority ranking registered in the second priority ranking list are added to an appraised value of the each item registered in the property management table; establishing means for establishing communication connections between opposing devices via communication media selected by the selecting means; and communicating means for communicating via the communication connection according to the application program. By means of this communication terminal, a communication connection is established via communication media selected according to the property management table, the first priority ranking list, and the second priority ranking list. In another aspect, this communication terminal may include acquiring means for acquiring the property management table from a predetermined control device. By means of this communication terminal, a communication connection is established via communication media selected according to a property management table acquired from a control device. In still another aspect, the plurality of items may include at least a communication speed. The communication terminal may further include: measuring means for measuring the communication speed when communication is performed according to the application program via a communication connection established by the establishing means; and transmitting means for transmitting, to the control device, data showing the communication speed measured by a measuring means as triggered by a completion of communication according to the application program by associating with an identifier that uniquely identifies communication media selected by the selecting means. By means of this communication terminal, data indicating the communication speed is transmitted to the control device corresponding to an identifier that uniquely identifies selected communication media. Furthermore, to resolve the above issues, according to another aspect of the present invention, there is provided control device, including: a property management table in which an appraised value of each of a plurality of types of communication media is registered for each of a predetermined plurality of items showing communication media properties; a first priority ranking list in which a priority ranking for each of the plurality of items assigned by communication terminal users is registered; a second priority ranking list in which a priority ranking for each of the plurality of items assigned by an application program provider is registered; selecting means for selecting, from among the plurality of types of communication media, communication media for which the communication should be mediated in response to the results of an addition, in which a first weighting granted for an item in response to a priority ranking registered in the first priority ranking list and a second weighting granted for the item in response to a priority ranking registered in the second priority ranking list are added to an appraised value of the each item registered in the property management table for each of the plurality of types of communication media in the event that the communication terminal communicates with an opposing device according to the application program; and notifying means for notifying the communication terminal of the results of a selection by the selecting means. By means of this control device, communication media selected according to the property management table, the first priority ranking list, and the second priority ranking list are notified. Furthermore, to resolve the above issues, according to yet another aspect of the present invention, there is provided a communication system including a control device by which a communication terminal communicates with a relevant communication terminal via the communication connection according to a predetermined application program, the communication terminal establishing a connection with an opposing device, wherein: the control device includes: a property management table in which an appraised value of each of a plurality of types of communication media is registered for each of a predetermined plurality of items showing communication media properties; and transmitting means for transmitting relevant property management table to the communication terminal in response to a request from the communication terminal, and the communication terminal includes: a first priority ranking list in which a priority ranking assigned by users for each of the plurality of items is registered; a second priority ranking list in which a priority ranking assigned by a provider of the application program for each of the plurality of items is registered; selecting means for selecting one from among the plurality of types of communication media in response to the results of an addition, in which a first weighting granted for an item in response to a priority ranking registered in the second priority ranking list and a second weighting granted for the item in response to a priority ranking registered in the second priority ranking list are added to an appraised value of the each item registered in the property management table for each of the plurality of types of communication media when a commencement of communication is specified by the application program; and establishing means for establishing a communication connection between the opposing devices via communication media selected by the selecting means. By means of this communication system, a communication connection is established via communication media selected according to the property management table, the first priority ranking list, and the second priority ranking list. Furthermore, to resolve the above issues, according to yet another aspect of the present invention, there is provided a communication system including a control device by which a communication terminal communicates with a relevant communication terminal via the communication connection according to a predetermined application program, the communication terminal establishing a connection with an opposing device, wherein: the control device includes a property management table in which an appraised value of each of a plurality of types of communication media is registered for each of a predetermined plurality of items showing communication media properties; the communication terminal includes a first priority ranking list in which a priority ranking assigned by communication terminal users for each of the plurality of items is registered; the communication terminal further includes a second priority ranking list in which a priority ranking assigned by a provider of the application program for each of the plurality of items is registered; the communication terminal further includes establishing means for establishing communication connections between the opposing devices via communication media that is notified by the control device as access point communication media while the first and second priority ranking lists are transmitted to the control device when a commencement of communication is specified according to the application program, the control device has selecting means for selecting, from among the plurality of types of communication media, communication media for which the communication should be mediated in response to the results of an addition, in which a first weighting granted in response to a priority ranking registered in a first priority ranking list received from the communication terminal and a second weighting granted in response to a priority ranking registered in a second priority ranking list received from the communication terminal are added to an appraised value of the each item registered in the property management table for each of the plurality of types of communication media when the communication terminal communicates with an opposing device according to the application program; and the control device has a notifying means for notifying the communication terminal of results of a selection by the selecting means. By means of this communication system, communication media selected according to the property management table, the first priority ranking list, and the second priority ranking list are notified. Furthermore, to resolve the above issues, according to yet another aspect of the present invention, there is provided a program causing a computer device to execute a process, the computer device including a property management table in which an appraised value is registered for each of a predetermined plurality of items showing communication media properties for each of a plurality of types of communication media, a first priority ranking list in which a priority ranking assigned by users for each of the plurality of items is registered, and a second priority ranking list in which a priority ranking assigned by a provider of the application program for each of the plurality of items is registered, the process including: selecting one from among the plurality of types of communication media in response to the results of an addition, in which a first weighting granted for an item in response to a priority ranking registered in the first priority ranking list and a second weighting granted for the item in response to a priority ranking registered in the second priority ranking list are added to an appraised value of the each item registered in the property management table for each of the plurality of types of communication media when a commencement of communication is specified according to a predetermined application program; establishing a communication connection between opposing devices via the selected communication media; and communicating via the communication connection according to the application program. By means of this program, a communication connection is established via communication media selected according to the property management table, the first priority ranking list, and the second priority ranking list. Furthermore, to resolve the above issues, according to yet another aspect of the present invention, there is provided a program causing a computer device to execute a process, the computer device including a property management table in which an appraised value of each of a plurality of types of communication media is registered for each of a predetermined plurality of items showing communication media properties, a first priority ranking list in which a priority ranking assigned by communication terminal users is registered for each of the plurality of items, and a second priority ranking list in which a priority ranking assigned by a provider of an application program for each of the plurality of items is registered, the process including: selecting, from among the plurality of types of communication media, communication media for which the communication should be mediated in response to the results of an addition, in which a first weighting granted for an item in response to a priority ranking registered in the first priority ranking list and a second weighting granted for the item in response to a priority ranking registered in the second priority ranking list are added to an appraised value of the each item registered in the property management table for each of the plurality of types of communication media when the communication terminal communicates with an opposing device according to the application program; and notifying the communication terminal of the results of a selection. By means of this program, a communication connection via communication media selected according to the property management table, the first priority ranking list, and the second priority ranking list is notified. BRIEF DESCRIPTION OF THE DRAWINGS Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein: FIG. 1 shows an example of the configuration of a communication system 10 relative to the first exemplary embodiment of the present invention; FIG. 2 shows an example of a property management table stored in a control device 300 ; FIG. 3 shows an example of the hardware configuration of a communication terminal 100 ; FIG. 4 shows an example of a software module realized by the CPU 110 a of a communication terminal 100 executing various programs; FIG. 5 shows an example of a priority ranking list stored in a communication terminal 100 ; FIG. 6 is a flowchart showing the flow of an access point NW selection process executed by a CPU 110 a; FIG. 7 is a drawing showing an example of the configuration of a communication system 20 relative to a second exemplary embodiment of the present invention; FIG. 8 shows an example of the hardware configuration of a control device 800 ; FIG. 9 is a flowchart showing an access point NW selection process executed by the CPU 110 a of a communication terminal 700 ; FIG. 10 is a flowchart showing the flow of an access point notification process executed by a CPU 810 according to an access point notification program. DESCRIPTION OF REFERENCE SYMBOLS 10 , 20 —communication systems; 100 , 700 —communication terminals; 200 , 200 a , 200 b , 200 c —wireless communication networks; 210 , 210 a , 210 b , 210 c —base stations (BS); 300 , 800 —control devices; 400 —gateway (GW); 500 —communication network; 600 —content server; 110 —control part; 110 a , 810 —CPUs; 110 b —ROM; 110 c —RAM; 110 d —EEPROM; 120 —wireless communication part; 120 a —first wireless communication IF unit; 120 b —second wireless communication IF unit; 120 c —third wireless communication IF unit; 820 —communication IF unit; 130 —operation unit; 140 —display unit; 830 —memory; 830 a —volatile memory; 830 b —non-volatile memory; 150 , 840 —buses DETAILED DESCRIPTION Below, exemplary embodiments for implementing the present invention will be explained while referring to the drawings. A: First Exemplary Embodiment A-1: Configuration FIG. 1 shows an example configuration of a communication system 10 relative to an exemplary embodiment of the present invention. As shown in FIG. 1 , the communication system 10 includes: a communication terminal 100 constituting a mobile telephone provided, for example, with a program execution function; three possible types of wireless communication networks accommodating this communication terminal 100 (specifically, wireless communication networks 200 a , 200 b , and 200 c ); and a communication network 500 connected to wireless communication networks 200 a , 200 b , and 200 c via a gateway (hereinafter represented as “GW”) 400 . The wireless communication networks 200 a , 200 b , and 200 c may be a communication network conforming, for example, to the PDC (Personal Digital Cellular) standard, GSM (Global System for Mobile Communications) standard, or IMT-2000 (International Mobile Telecommunication-2000), or may be a wireless LAN (Local Area Network) or the like as specified, for example, by “IEEE 802.11b”, which is the specification for Ethernet (registered trademark). Further details are described below, but the three wireless communication networks above have different properties, such as the fee structure and the degree to which security is ensured. Note that FIG. 1 shows examples regarding a case in which the properties of the three different types of wireless communication networks are mutually included in a communication system 10 , but the wireless communication networks included in the communication system 10 may consist of two types, and furthermore may consist of four or more types. The point is that the properties mutually differ, and moreover, that the multiple wireless communication networks in which it is possible to include a communication terminal 100 at least include a communication system 10 . In the communication network 500 , such as the Internet, for example, a content server 600 providing information retrieval services or providing various digital content (e.g., melodic data) is connected. Note that a detailed description of the configuration of the content server 600 has been omitted, as it does not consist of any changes from the configuration (hardware configuration and software configuration) of a general content server. Furthermore, in the present exemplary embodiment, the communication network 500 will be described with regard to the case of the Internet, but of course it may also be a LAN. The GW 400 mediates communication between the communication terminal 100 accommodated in any of the wireless communication networks 200 a , 200 b , or 200 c and the content server 600 connected to the communication network 500 , and is provided with a function of interconverting between the communication protocol of each wireless communication network above and the communication protocol of the communication network 500 . Note that a detailed description of the GW 400 has been omitted, as there is no change from the configuration of a general gateway device. Furthermore, in FIG. 1 , a case is described in which the wireless communication networks 200 a , 200 b , and 200 c are connected to the communication network 500 via the GW 400 , but of course each wireless communication network may be connected to the communication network 500 via a different gateway device. The wireless communication networks 200 a , 200 b , and 200 c accommodate a communication terminal 100 and provide wireless communication services, and include base stations (hereinafter represented as “BS”) 210 a , 210 b , and 210 c that establish wireless links with the communication terminal 100 . Note that, below, in cases in which it is not necessary to distinguish among the three types of wireless communication networks above, such is represented as “wireless communication network 200 ”. Similarly, in cases in which it is not necessary to distinguish among each of the three types of BS above, such is represented as “BS 210 ”. The BS 210 arranges each cell divided into multiple cells having a predetermined width (e.g., 500-meter radius) above ground, establishes wireless links between communication terminals within the range of the cells, and accommodates the communication terminals thereof. The BS 210 receives data that has been transmitted from a communication terminal that the station itself accommodates and sends the data to a wireless communication network 200 to which the station itself is connected. Furthermore, the BS 210 receives data that has been transmitted from the wireless communication network 200 to the communication terminal address and sends the data wirelessly within a cell that is subordinate to the station itself. Note that, in the communication system 10 shown in FIG. 1 , each of the wireless communication networks 200 a , 200 b , and 200 c has a variety of inherent properties with respect to each item regarding the degree to which security is ensured (in the present exemplary embodiment, whether they are compatible with encrypted communication), the fee structure, and whether handover is possible between wireless communication networks. Specifically, the wireless communication network 200 a has a pay-as-you-go fee structure (usage based fee structure) in which a usage fee is charged according to the transferred data volume, and furthermore, is compatible with both encrypted communication and unencrypted communication. The wireless communication network 200 b has a pay-as-you-go fee structure, and furthermore, is compatible only with unencrypted communication. Moreover, the wireless communication network 200 c is a communication network having a flat-rate system fee structure in which a flat-rate usage fee is charged in predetermined period units such as January, for example, and is compatible with both encrypted communication and unencrypted communication. In addition, among the three types of wireless communication networks above, there are properties in which the wireless communication network 200 a and the wireless communication network 200 b are compatible with handover between wireless communication networks and the wireless communication network 200 c is incompatible with handover with other wireless communication networks. FIG. 2(A) shows an example of a property management table displaying each wireless communication network property above. In the property management table shown in FIG. 2(A) , parameters displaying the degree to which security is ensured, the fee structure, and whether handover is possible are registered corresponding to network identifiers (hereinafter, “NW identifier”) that uniquely identify each wireless communication network. Note that, in the present exemplary embodiment, the wireless communication networks 200 a , 200 b , and 200 c have respectively been assigned “001”, “002”, and “003” as NW identifiers. Furthermore, the network addresses may also, of course, be used for assigning the NW identifiers above to each wireless communication network. In FIG. 2(A) , the parameter showing the degree to which security is ensured is “1” or “0”. “1” indicates compatibility with encrypted communication, and “0” indicates incompatibility with encrypted communication. Similarly, in FIG. 2(A) , the parameter that shows the fee structure is also “1” or “0”. “1” indicates pay-as-you-go, and “0” indicates a flat-rate system. Furthermore, in FIG. 2(A) , the parameter that indicates whether handover is possible is also “1” or “0”. “1” indicates that handover is possible, and “0” indicates that handover is not possible. Note that the possibility of encrypted communication, the fee structure, and the possibility of handover are always constant regardless of the time zone that the wireless communication network utilizes, so the property management table shown in FIG. 2(A) indicates properties irrelevant to time zones. In contrast, in the property management table shown in FIG. 2(B) , among the properties of each wireless communication network, parameters indicating properties that change according to time are stored corresponding to the NW identifiers above. Specifically, in the property management table shown in FIG. 2(B) , the NW identifiers above are coordinated, and values indicating the communication speed (the data transfer speed in the present exemplary embodiment) of the wireless communication networks identified by the NW identifiers measured in three time zones,—12:00 midnight to 8:00 a.m. ( FIG. 2(B) : time zone 1 ), 8:00 a.m. to 4:00 p.m. ( FIG. 2(B) : time zone 2 ), 4:00 p.m. to 12:00 midnight the next day ( FIG. 2(B) : time zone 3 ),—are stored in Mbps units. Note that, in the present exemplary embodiment, data indicating the communication speed is described in the case of using the data transfer speed, but the response speed may also of course be used. In the present exemplary embodiment, the two types of property management tables shown in FIGS. 2(A) and (B) are stored in the control device 300 . Hereinafter, the property management table shown in FIG. 2(A) is referred to as the “first property management table”, and the property management table shown in FIG. 2(B) is referred to as the “second property management table”. Note that the present exemplary embodiment is described using a case in which each day is divided into three time zones and the data transfer speed of each wireless communication network in each time zone is stored in the second property management table, but each day may also of course be divided into two time zones of a.m. and p.m., for example, with the data transfer speed of each time zone being stored in the second property management table, and furthermore, each day may be divided into four or more time zones, with the data transfer speed in each time zone being stored in the second property management table. Moreover, the present exemplary embodiment is described using a case in which a property management table indicating wireless communication network properties independent of time zones and a property management table indicating properties dependent on time zones are separately stored in the control device 300 , but of course an integrated property management table of both of these as shown in FIG. 2(C) may also be stored in the control device 300 . The control device 300 in FIG. 1 is connected to a wireless communication network 200 a . The control device 300 has a function of responding to the storage content of the first management table above in response to a request from the communication terminal 100 as well as to the data transfer speed of each wireless communication network in the time zone corresponding to the time at which that request was received, and a function of receiving the data transfer speed, from the communication terminal 100 , measured at the time at which the communication terminal 100 communicated data with the content server 600 and a function of renewing the storage content of the second property management table. Accordingly, a detailed description of the control device 300 has been omitted, because the control device 300 has a function identical to that of a general server device that performs data replies and data updates in response to requests from a communication terminal 100 . In addition to a configuration (e.g., a voice telephone call part) for providing a wireless telephone service via a mobile telephone network not shown in the drawing, as shown in FIG. 3 , the communication terminal 100 is provided with a control unit 110 , a wireless communication unit 120 (an example of communicating means), an operation unit 130 , a display unit 140 , and a bus 150 that mediates data exchange among these configuration elements. As shown in FIG. 3 , the control unit 110 includes a CPU (Central Processing Unit) 110 a , ROM (Read Only Memory) 110 b (an example of selecting means, establishing means, acquiring means, measuring means, and transmitting means), RAM (Random Access Memory) 110 c , and EEPROM (Electronically Erasable and Programmable ROM) 110 d. The CPU 110 a executes a program stored in the ROM 110 b or EEPROM 110 d with the RAM 110 c as the work area and thereby controls the operation of each part of the communication terminal 100 . Note that, in addition to storing the data and/or program to be described later, the EEPROM 110 d functions also as a so-called address book, wherein telephone numbers, e-mail addresses, etc., are stored in list format. Furthermore, the communication address of the previously described control device 300 is also stored in the EEPROM 110 d. As shown in FIG. 3 , the wireless communication unit 120 includes a first wireless communication interface (hereinafter, IF) part 120 a , a second wireless communication IF unit 120 b , and a third wireless communication IF unit 120 c . The first wireless communication IF unit 120 a establishes a wireless link with the BS 210 a under the control of the control unit 110 and wirelessly exchanges data with this BS 210 a . Similarly, the second wireless communication IF unit 120 b establishes a wireless link with the BS 210 b under the control of the control unit 110 and wirelessly exchanges data, and the third wireless communication IF unit 120 c establishes a wireless link with the BS 210 c under the control of the control unit 110 and wirelessly exchanges data. The operation unit 130 is provided with an operator such as a button, and supplies an operation signal to the control unit 110 in response to an operation by the user. The display unit 140 includes a liquid crystal display and the drive circuit thereof and displays graphic images in response to graphic data supplied by the control unit 110 . A number of programs are stored beforehand in the ROM 110 b . Hereinafter, these are referred to as “preinstalled programs”. A multitask operating system (hereinafter referred to as “multitask OS”), the Java (registered trademark) platform, and native applications are included as examples of these preinstalled programs. A multitask OS is an operating system that supports various functions, such as the allocation of virtual memory space necessary for the realization of multitask pseudo parallel execution via a TSS (Time-Sharing System). A Java platform is a group of programs written according to the CDC (Connected Device Configuration), which is a configuration for realizing the Java execution environment 114 to be described later in mobile telephones with a built-in multitask OS. A native application is a program that realizes the basic service of a communication terminal 100 such as browsing Web pages or exchanging e-mail, or is an application (e.g., a mailer 113 to be described later) or the like for receiving the provision of an e-mail exchange service or a so-called Web browser (e.g., a browser 112 to be described later). The EEPROM 110 d includes a Java application storage region in which Java applications are stored. A Java application includes a JAR (Java Archive) file in which graphic image files and/or sound clips are compiled to be utilized in conjunction with an program body in which the procedure of a process itself is described in addition to the execution of that program body in a Java execution environment, and also includes an ADF (Application Descriptor File) in which the installation and launching of the JAR file as well as various attributes are written. These Java applications are created by a CP, stored on a content server 600 or the like, and are arbitrarily downloaded via the use of the Web browser above. FIG. 4 is a drawing showing an example of a software module realized via the execution, by a CPU 110 a , of various programs stored in the ROM 110 b and EEPROM 110 d . By the CPU 110 a executing various programs in the communication terminal 100 , the browser 112 , mailer 113 , and Java execution environment 114 are realized in the OS 111 as shown in FIG. 4 , and furthermore, a first storage 115 and a second storage 116 are secured in the EEPROM 110 d. The Java execution environment 114 is realized via the Java platform in the ROM 110 c . The Java execution environment 114 includes a class library 117 , JVM (Java Virtual Machine) 118 , and JAM (Java Application Manager) 119 . A class library 117 is the compilation of a group of program modules (classes) having specific functions into a single file. A communication control program that selects any one of the three wireless communication networks described above and establishes a communication connection between opposing devices is an example of a program module included in a class library 117 . The JVM 118 has a function of interpreting and executing byte code provided as a Java application and is optimized for the CDC mentioned above. The JAM 119 has a function of managing the download and installation of Java applications as well as the launching and exiting of the same. The first storage 115 is a region for storing Java applications (Jar files and ADF) downloaded under management by the JAM 119 . The second storage 116 is a region for storing data created during the execution of a Java application after exiting the same, wherein individual storage regions are allocated for each installed Java application. Furthermore, data in a storage region allocated by a certain Java application is rewritable only while the Java application is being executed, and it is designed so that other Java applications cannot write therein at that time. Incidentally, in the first storage 115 of the communication terminal 100 , a communication connection is established with the content server 600 , and a Java application that communicates data is stored beforehand. The CPU 110 a that executes this Java application in the Java execution environment 114 calls a previously mentioned communication control program, selects one from among any of the three wireless communication networks mentioned above, and establishes a communication connection, and in the event of that selection, the CPU 110 a selects the wireless communication network that is most able to respond to both the demand of the CP, which is the provider of the Java application, as well as the demand (whether emphasis is placed on any item among each item that displays the communication network properties) of the user of the terminal itself. To explain this more specifically, the first priority ranking list (see FIG. 5(A) ) indicating the user demand is stored in the EEPROM 110 d of the communication terminal 100 , and the second priority ranking list (see FIG. 5(B) ) indicating the CP demand is stored in the ADF of the Java application described above. The second priority ranking list is determined by each of a variety of Java applications because the second priority ranking list is written in the ADF of various Java applications. In FIGS. 5(A) and (B), priority ranking “1” is written by the compiler of the priority ranking list (i.e., a user or CP) for the item with the highest priority, and priority ranking “0” is written for the other items. As is clear from referring to FIGS. 5(A) and (B), in the present exemplary embodiment, the user of the communication terminal 100 places priority on the data transfer speed, and the CP places priority on the degree to which security is ensured. Before establishing a communication connection, the CPU 110 a that is operating according to the communication control program above communicates with the control device 300 , acquires storage content of the first and second property management tables, and then executes a process of selecting the wireless communication network in which the result of calculation is the largest, wherein a weighting (in the present exemplary embodiment, 10 in the case in which the priority ranking is “1”, and “0” in the case in which the priority ranking is “0”) for the item granted in response to a priority ranking registered in a first and a second priority ranking list are added to an appraised value of each item stored in these property management tables for each of the three wireless communication networks above. Thereby, the wireless communication network that may best respond to both the demand of the user of the terminal itself and the demand of the CP, which is the provider of the Java application, is selected. Note that, as shown in FIG. 5(A) and FIG. 5(B) , the present exemplary embodiment is described in the case in which priority ranking “1” is written for the item in which the compiler of the priority ranking list (i.e., the user or CP) places the highest priority, and priority ranking “0” is written for the other items, but as shown in FIG. 5(C) , the order of each item in which the compiler of the priority ranking list places the most importance is written as the priority ranking of those items, but of course the sum may be calculated by granting a weighting (as long as the corresponding relationship between the priority ranking and the weighting is determined appropriately, such as a weighting of 10 if the priority ranking is “1”, a weighting of 8 if the priority ranking is “2”, etc.) according to the priority ranking when the sum of the appraised values above is computed. Furthermore, the present exemplary embodiment is described in the case in which the second priority ranking list includes the ADF, but of course the second priority ranking list may also be included in the Jar. This concludes the configuration of the communication terminal 100 . As described above, the hardware configuration of the communication terminal 100 is identical to the hardware configuration of a mobile telephone provided with a program execution function, and functions that are characteristic of communication terminals according to an aspect of the present invention are realized via software modules. A-2: Operations Next, operations characteristic of the communication terminal according to an aspect of the present invention among operations performed by the CPU 110 a according to various programs in the communication terminal 100 will be described while referring to the drawings. A user of a communication terminal 100 may specify the execution of a Java application via appropriate operation of an operation unit 130 . Below, an example of the present operation is described using a case in which the execution of a Java application that communicates data with a content server 600 is specified. When the execution of a Java application is specified as described above, the CPU 110 a reads out the corresponding Java application from the EEPROM 110 d according to the JAM 119 mentioned above, and commences the execution according to the JVM 118 . As mentioned above, the Java application executed in the example of the present operation is a Java application that communicates data with a content server 600 , and includes Java byte code for calling the communication control program mentioned above. The CPU 110 a that operates according to the JVM 118 interprets and executes this Java byte code, calls a communication control program from the class library 117 , and executes the same. FIG. 6 is a flowchart showing the flow of an access point NW selection process executed by a CPU 110 a that is operated according to a communication control program. As shown in FIG. 6 , the CPU 110 a first establishes a communication connection with the control device 300 , and then acquires storage content of the first and the second property management tables (step SA 100 ). To explain this more specifically, the CPU 110 a creates a communication message requesting the transmission of storage content of the first and second property management tables, and transmits this communication message addressed to the control device 300 . In this way, the communication message transmitted from the communication terminal 100 is appropriately routed within the wireless communication network 200 a and reaches the control device 300 . If the control device 300 received this communication message, the control device 300 creates a communication message in which the storage content of the first property management table and the storage content of the second property management table corresponding to the time at which the communication message above was received (i.e., the data transfer speed for the time zone corresponding to the reception time) are written, and replies to the communication terminal 100 . Thus, the communication message replied by the control device 300 is appropriately routed within the wireless communication network 200 a and reaches the communication terminal 100 . When the CPU 110 a of the communication terminal 100 receives the communication message replied by the control device 300 via the first wireless communication IF unit 120 a , the CPU 110 a analyzes the communication message and obtains the storage content of the first and second property management tables. Next, according to the storage content of the first and second property management tables obtained in step SA 100 as well as the list content of the previously mentioned first and second priority ranking lists, the CPU 110 a computes the sum of the appraised values of each item while granting the aforementioned weighting for each of the wireless communication networks 200 a , 200 b , and 200 c (step SA 110 ). The CPU 110 a stores the computed sum in the RAM 110 c corresponding to the NW identifier of the wireless communication network. At this time, the CPU 110 a reads out the aforementioned second priority ranking list from the ADF of the Java application while attempting communication, and acts according to the content thereof. In the example of the present operations, the content of the first and the second priority ranking lists is as in FIG. 5(A) and FIG. 5(B) , and the storage content of the first and the second property management tables is as in FIG. 2(A) and FIG. 5(B) , so in a case in which the time at which the execution of the Java application above is specified belongs to time zone 1 , the sum of the appraised values for each of the wireless communication networks 200 a , 200 b , and 200 c is computed as follows. Specifically, the sum of the appraised values computed for the wireless communication network 200 a is 1.0×10 (security)+0.5×10 (transfer speed)=15, the sum of the appraised values computed for the wireless communication network 200 b is 1.0×10 (transfer speed)=10, and the sum of the appraised values computed for the wireless communication network 200 c is 1.0×10 (security)+0.7×10 (transfer speed)=17. Next, the CPU 110 a selects the largest sum of the appraised values computed in step SA 110 from among the wireless communication networks 200 a , 200 b , and 200 c as the access point NW (step SA 120 ), and establishes a communication connection with the content server 600 via the wireless communication network identified by the NW identifier (step SA 130 ). Note that, in a case in which multiple wireless communication networks in which the sums of the appraised values computed in step SA 110 are all the largest, the NW identifiers thereof are displayed on the display unit 140 , and an access point NW may be selected by the user from among these. In the example of the present operations, the sum of the appraised values computed for the wireless communication network 200 c is the largest, so the wireless communication network 200 c is selected as the access point NW in step SA 120 , a wireless link is connected with the BS 210 c in step SB 130 , and a communication connection is established. Thereafter, the CPU 110 a communicates data with the content server 600 via the communication connection. Meanwhile, in the process of executing the communication control program, the CPU 110 a determines whether data communication has been completed according to the Java application above (step SA 140 ). The CPU 110 a measures the data transfer speed (step SA 150 ) during the resulting determination is “No”. Note that a well-known algorithm may be used for measurement of the data transfer speed. Furthermore, when the resulting determination in step SA 140 becomes “Yes”, the CPU 110 a disconnects (step SA 160 ) the communication connection that was established in step SA 130 . The CPU 110 a transmits (step SA 170 ), to control device 300 , data indicating the data transfer speed measured in step SA 150 corresponding to the NW identifier selected in step SA 120 , and terminates the present access point selection process. The aspect that should receive the most attention here is the aspect in which the wireless communication network 200 c is selected as the access point NW in the example of the operation above, wherein the sum of the appraised values for the wireless communication network 200 b was the largest (specifically, the communication network that corresponded the most to only the user demand was the wireless communication network 200 b ), and if the weighting based only on the second priority ranking list and the computed sum of the appraised values were performed, the sum of the appraised values of the wireless communication networks 200 a and 200 c were the largest (specifically, the communication network that most responded to the CP demand was either of the wireless communication networks 200 a or 200 c ) when a weighting is granted based only on the first priority ranking list, and the sum of the appraised values is computed. As is clear in referring to FIG. 2(A) , the wireless communication network 200 c is capable of encrypted communication, so this wireless communication network 200 c meets the CP demand wherein priority is placed on ensuring security. Furthermore, as is clear in referring to FIG. 2(B) , the data transfer speed of the wireless communication network 200 c is faster than that of the wireless communication network 200 a , so this wireless communication network 200 c meets the user demand in which priority is placed on the data transfer speed. Thus, as a result of the operations explained above, a communication connection is established with the content server 600 via a wireless communication network that meets the highest limits of both the CP demand (emphasis on security) and the user demand (emphasis on data transfer speed). Moreover, according to an aspect of the present exemplary embodiment, the user of the communication terminal 100 may create a first priority ranking list that reflects the user's own demand and store the first priority ranking list in the communication terminal 100 . It is not necessary to perform the burdensome task of selecting the network that is most relevant to the user's own demand from among multiple wireless communication networks for each communication. B: Second Exemplary Embodiment Next, a second exemplary embodiment of the present invention is described while referring to the drawings. B-1: Configuration FIG. 7 is a drawing showing an example configuration of a communication system 20 relative to the second exemplary embodiment of the present invention. Note that symbols that are the same as those in FIG. 1 have been affixed in FIG. 7 for configuration elements that are the same as those in the communication system 10 mentioned above. As is clear from contrasting FIG. 7 with FIG. 1 , the aspects whereby communication system 20 differs from communication system 10 are the aspect wherein the communication system 10 includes a communication terminal 700 instead of the communication terminal 100 and the aspect wherein the communication system 10 includes a control device 800 instead of the control device 300 . Below is an explanation centering on the communication terminal 700 and the control device 800 , which are the aspects that differ from the communication system 10 . The communication terminal 700 is a mobile telephone provided with a Java execution environment similarly to the communication terminal 100 , and the hardware configuration thereof is identical to the hardware configuration of the communication terminal 100 (see FIG. 3 ). Furthermore, various software modules of a multitask OS, browser, mailer, and Java execution environment are realized by the CPU 110 a of the communication terminal 700 executing various programs stored in the ROM 110 b or EEPROM 110 d (see FIG. 4 ), and reserving of the first and the second storage in the EEPROM 110 d (see FIG. 4 ) is identical to that of the communication terminal 100 described above. However, with regard to the communication control program that executes the access point NW selection process within the Java execution environment of the communication terminal 700 , because one that is different than that in the communication terminal 100 is registered in the class library, an access point NW selection process that is different from the access point NW selection process (see FIG. 6 ) in the first exemplary embodiment described above is executed. Next, the control device 800 is described. FIG. 8 shows an example hardware configuration of the control device 800 . The control device 800 as shown in FIG. 8 includes a CPU 810 (an example of selecting means and notifying means), a communication IF unit 820 , a memory 830 , and a bus 840 that mediates data exchange among these configuration elements. The CPU 810 controls the operation of each part according to various programs stored in the memory 830 . The communication IF unit 820 may be an NIC (Network Interface Card), for example, and is connected via a cable to the wireless communication network 200 a . While receiving data that has been transmitted from the wireless communication network 200 a and transferring the data to the CPU 810 , this communication IF unit 820 sends data transferred from the CPU 810 to the wireless communication network 200 a. As shown in FIG. 8 , the memory 830 includes a volatile memory 830 a and a non-volatile memory 830 b . The volatile memory 830 a may be a RAM, for example, and is utilized as a work area while the CPU 810 executes various programs. On the other hand, the non-volatile memory 830 b may be a hard disk, for example, and stores various data and various programs. The above-mentioned first and second property management tables (see FIG. 2 ) are examples of data stored in this non-volatile memory 830 b , and the access point notification program in which the OS program for realizing the above-mentioned OS is executed by the CPU 810 , and the access point NW notification process that is characteristic of the control device relative to the present invention is executed by the CPU 810 are examples of programs stored in this non-volatile memory 830 b. In the present exemplary embodiment, when the power (omitted from the drawing) of the control device 800 is turned on, the CPU 810 first loads the OS program from the non-volatile memory 830 b into the volatile memory 830 a , and commences the execution thereof. Furthermore, the CPU 810 , which has switched to a state in which execution of the OS program has been completed and the OS is realized, loads the access point notification program from the non-volatile memory 830 b into the volatile memory 830 a and commences the execution thereof. The operation performed by the CPU 810 of operating according to this access point notification program is described in detail below. As described above, the hardware configuration of the control device 800 does not change in any way from the hardware configuration of a general computer device, and the functions that are characteristic of the control device relative to the present invention are all realized as software modules. This concludes the configuration of the control device 800 above. B-2: Operations Next, operations that significantly show the characteristics of the operations performed by the communication terminal 700 and the control device 800 will be described while referring to the drawings. FIG. 9 is a flowchart showing the flow of an access point NW selection process that the CPU 110 a of the communication terminal 700 performs according to the communication control program. As is clear from contrasting FIG. 9 with FIG. 6 , the aspect whereby the access point NW selection process shown in FIG. 9 differs from the access point NW selection process shown in FIG. 6 is the aspect wherein the process shown in FIG. 9 has step SB 100 and step SB 110 instead of step SA 100 to step SA 120 . In step SB 100 of FIG. 9 , the CPU 110 a reads out the first and the second priority ranking lists stored in the EEPROM 110 d , creates a communication message (hereinafter, “access point notification request message”) in which these first and second priority ranking lists are written. The CPU 110 a transmits the access point notification request message addressed to the control device 800 . The access point notification request message transmitted from the communication terminal 700 in this way is appropriately routed by the network equipment (omitted from FIG. 7 ) within the wireless communication network 200 a and reaches the control device 800 , which is the destination thereof. FIG. 10 is a flowchart showing the flow of the access point NW notification process that the CPU 810 of the control device 800 performs according to the communication management program above. As shown in FIG. 10 , when the CPU 810 receives (step SC 100 ) the access point notification request message above via the communication IF unit 820 , the CPU 810 computes the appraised values of each of the wireless communication networks 200 a , 200 b , and 200 c according to the first and the second priority ranking lists that are not in the access point notification request message as well as the storage content of the first and the second property management tables stored in the non-volatile memory 830 b . Note that the detailed description of the process that the CPU 810 performs in this step SC 110 has been omitted, because it is identical to the process that the CPU 110 a of the communication terminal 100 performs in step SA 110 of the flowchart shown in FIG. 6 . Next, the CPU 810 selects the wireless communication network with the largest appraised value computed in step SC 110 as the wireless communication network to which the communication terminal 700 should connect (step SC 120 ), and creates a communication message (hereinafter, “access point notification message”) in which the NW identifier of the wireless communication network is written. The CPU 810 notifies the results of this selection. Specifically, in other words, the access point notification message is replied to, addressed to the source of the access point notification request message above (step SC 130 ). An access point notification message transmitted from the control device 800 in this way is appropriately routed by the network equipment within the wireless communication network 200 a and reaches the communication terminal 700 . Returning to FIG. 9 , when the CPU 110 a of the communication terminal 700 receives the access point notification message above via the wireless communication unit 120 (step SB 110 ), the CPU 110 a reads out the NW identifier written in the message and executes the process following step SA 130 mentioned above. As a result of the operations performed as explained above, similarly to that in the first exemplary embodiment mentioned above, a communication connection is established between the communication terminal 700 and the content server 600 via the wireless communication network 200 c and the communication network 500 , and data communication is commenced between the communication terminal 700 and the content server 600 . Note that while data is being communicated with the content server 600 via the wireless communication network and the communication network 500 identified by the NW identifier above, the aspect of notifying the control device 800 of the results of the measurement is the same as in the first exemplary embodiment described above at the time in which the data transfer speed thereof is measured and the data communication is completed. Meanwhile, in a case in which the data transfer speed data and NW identifier that have been transmitted from the communication terminal 700 are received, the aspect whereby the storage content of the second property management table is updated by the data transfer speed data is also the same as in the first exemplary embodiment described above. Thus, the effect obtained by the present second exemplary embodiment is identical to that of the first exemplary embodiment described above. C: Modifications Above, exemplary embodiments for implementing the present invention are described. However, modifications such as those mentioned below may also of course be applied. Two or more examples of the modification described below may also be combined and used. The first and the second exemplary embodiments described above are described using a case in which the communication terminal 100 and the communication terminal 700 have a Java execution environment based on a CDC as the program execution environment, but they may also have a Java execution environment based on a CLDC, and a case in which they have a program execution environment other than a Java execution environment is also of course possible. Note that programs created and compiled in programming languages other than C++ are examples of the application program executed by a program execution environment other than a Java execution environment. The first and the second exemplary embodiments described above are described using a case in which they have program execution environments, and furthermore, provide the present invention in a mobile telephone capable of accommodating multiple types of wireless communication networks. However, a suitable application for the present invention is not limited to the mobile telephone above, and may include a PDA or notebook personal computer that has a program execution environment and is furthermore capable of accommodating multiple types of wireless communication networks, and moreover, may include a desktop personal computer that has a program execution environment and is furthermore capable of a wired connection to any of multiple types of communication networks. The point is that the present invention may be applied as long as it has a program execution environment, and furthermore that it is a communication terminal capable of establishing a communication connection with an opposing device via any of multiple types of communication networks and of communicating data. The first and the second exemplary embodiments described above are described using a case in which measurement of the data transfer speed and notification to the control device are executed by the communication terminal, but these may also of course be executed by the content server, which is the other party of the communication. Furthermore, the first and the second exemplary embodiments described above are shown as examples of the wireless communication networks 200 a , 200 b , 200 c , which each have base stations as the communication networks for the communication terminal 100 to perform communication, but they are not limited to these and may operate without base stations. In short, the present invention may be applied to any application as long as a communication terminal establishes a communication connection with an opposing device and it constitutes communication media that is capable of communication. Therefore, communication and the like that uses wireless communication or infrared according to specifications such as Bluetooth (registered trademark), for example, is also included within the concept of this “communication media”. In comparing wireless communication according to specifications such as Bluetooth (registered trademark), for example, with wireless communication using the wireless communication networks 200 a , 200 b , 200 c , the transfer speed is fast, and furthermore, the security is set to low while the communication fee is free of charge. Furthermore, a case is presupposed in which the users emphasize the communication fees in the first priority ranking list and the CP emphasize the transfer speed in the second priority ranking list. In this case, wireless communication according to the Bluetooth (registered trademark) specification corresponds to both user and CP demands, and the communication terminal is therefore configured to select wireless communication according to this Bluetooth (registered trademark) specification as the communication media that should be utilized. Moreover, the first and the second exemplary embodiments are described using a case in which the degree to which security is ensured, the fee structure, whether handover is possible, and data transfer speed are used as items indicating the wireless communication network properties, but of course other items such as the frequency of occurrence of communication errors may also be added, and conversely, any of the degree to which security is ensured, the fee structure, whether handover is possible, and/or data transfer speed may also be excluded. The aspect is that the appraised value of each communication network for the different multiple items is registered in the property management table, and a priority ranking list showing which of these multiple items has priority should be created by the user and CP of the communication terminal. Note that, in a case in which data transfer speed is excluded from the evaluation items, it is obviously unnecessary for the measurement of the data transfer speed and the notification to the control device to be performed by the communication terminal or content server. The first and the second exemplary embodiments described above are described using a case in which the communication network that should mediate the data communication is selected and a communication connection is established before the commencement of data communication by the application, and the communication connection is maintained (not disconnected) until the data communication is completed. However, communication by an application is generally divided into multiple types of stages, such as an authentication stage in which the authentication of an opposing device that is the other party of the communication, for example, and a data-exchange stage in which the data necessary for the execution of the application is actually exchanged, and it is also common for the network properties emphasized in each of these stages to differ. Therein, the above-mentioned first and second priority ranking lists are prepared beforehand for each stage, and the access point NW may also of course be selected for each stage. The first and the second exemplary embodiments are described using a case in which a heavy weighting is granted to values with a high priority ranking according to the first and the second priority ranking lists, the sum of the appraised values is computed, and the largest sum thereof is selected as the access point network. However, a smaller weighting may also be granted to values to the extent that the priority ranking is higher, the sum of the appraised values is computed, and the smallest sum thereof may of course be selected as the access point network. Furthermore, in a case in which a communication network that should be excluded by a user or the CP as a connection target is specified beforehand, and the communication network with the largest sum of appraised values is excluded from this as a suitable communication network, the one in which the sum of the appraised values above is the largest may be selected from among the communication networks that are excluded, and moreover, the weighting may be granted according to the third priority ranking list in addition to the first and the second priority ranking lists above, and the sum of the appraised values above may be computed. The point is that a communication network should be selected in response to the sum of the appraised values with a weighting granted according to the first and the second priority ranking lists (in other words, a communication network is selected with consideration of both the user demand and the CP demand). The first exemplary embodiment described above is described using a case wherein a communication control program in which a CPU executes an access point NW selection process that is characteristic of communication terminals relative to the present invention is stored beforehand in the ROM 110 b of the communication terminal 100 . However, the communication control program above may be written in computer-readable recording media (e.g., CD-ROM (Compact Disk-Read Only Memory) or DVD (Digital Versatile Disk), etc.) and be distributed, and furthermore, the communication control program above may be distributed by being downloaded via electrical communication lines such as the Internet. Furthermore, the second exemplary embodiment described above is described using a case in which a communication control program in which a CPU executes an access point NW selection process that is characteristic of a control device relative to the present invention is stored beforehand in the non-volatile memory 830 b of the control device 800 , but the relevant communication control program may also be distributed by being written in computer-readable recording media and may be distributed by being downloaded via electrical communication lines. The configuration of the hardware of the communication terminal and control device is not limited to those described in the exemplary embodiments. These devices may have any hardware configuration as long as they realize the necessary functional configuration. For example, in the exemplary embodiments described above, the CPU 110 a of the communication terminal 100 has multiple functions—specifically, the functions of selecting means, establishing means, acquiring means, measuring means, and transmitting means. However, at least some of these functions may be realized by hardware elements other than the CPU 110 a. Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular program or device to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of the appended claims.

A communication terminal providing optimal communication services between content providers comprising a property management table with an appraised value registered for each of a predetermined set of communication media properties for various types of communication media, a first user specified priority ranking list and a second priority ranking list specified by an application program provider with rankings for the set of communication media properties, whereby the desired communication medium is selected by adding weightings for priority from the first and second priority ranking lists and adding the appraised value for each item from the property management table and using the highest total to specify the optimum communication medium for use when commencement of communication is specified by a predetermined application program, and establishing communication connections between opposing devices using the selected optimum communication medium. Also disclosed are a communication system, control device and program including the communication terminal's elements.

CROSS-REFERENCE TO RELATED APPLICATION [0001] This patent application claims priority to U.S. Provisional Patent Application Ser. No. 62/081,214, filed Nov. 18, 2014, which is incorporated herein by reference in its entirety. BACKGROUND OF THE INVENTION [0002] The present invention relates generally to permanent magnet motors that include interior permanent magnets in a rotor. [0003] Permanent magnet brushless (PMBLDC or PMSM) motors may exhibit relatively high torque densities and are therefore useful in industrial drives for high performance applications. Permanent magnet (PM) motors with buried magnets are used in variable speed drives. [0004] The placement of magnets inside the magnet pockets of interior permanent magnet (IPM) motors with rectangular bar magnets is an issue due to the manufacturing tolerances of both magnet bars and magnet pockets. This magnet placement creates ripple torque depending on the slot/pole combination of the motor. For high performance applications, torque ripple is an important challenge for PM motors as it creates vibration and speed pulsation. Moreover, cogging torque minimization in IPM motors is more challenging compared to surface permanent magnet (SPM) motors. IPM motors allow for smaller air gaps and linear skewing. Shaping of the magnet presents design difficulties due to the rectangular shape of the permanent magnets. [0005] Various techniques have been attempted to minimize the cogging torque. Conventional techniques tend to add to the complexity and can negatively impact output torque. In addition, in motors employing sintered magnets, the increased complexity can contribute significantly to cost. [0006] Magnet pole shaping, skewing of rotor magnets or stator structures, step-skewing of rotor magnets, combining slots and poles, magnet shaping, and incorporation of notches in the stator teeth have been employed to minimize cogging torque in PM motors. Unfortunately, however, these conventional techniques cause additional design challenges. For example, the use of segmented stators, while bringing about improvements in slot fill and manufacturing time of the motor, have also given rise to certain undesirable harmonics, such as a large ninth order harmonic attributed to the gaps disposed between stator segments. [0007] Accordingly, it is desirable to have an improved rotor design and techniques for imbedding magnets in rotors of IBPM. SUMMARY OF THE INVENTION [0008] In one aspect of the invention, an interior permanent magnet motor comprises a housing, a ring-shaped stator fixed in the housing and having a coil which generates a magnetic field when a voltage is applied, a rotor being disposed for rotation within, and relative to the ring-shaped stator, the rotor comprises a shaft rotatably supported by the housing a magnetic plate pair disposed about an outer circumference of the rotor, wherein each magnetic plate of the magnetic plate pair has opposing sides that extend from the outer circumference toward the shaft, the opposing sides are bounded by an inner end of each magnetic plate, and a triangular member disposed between the magnetic plate pair and the shaft, the triangular member having a flat surface mated to each inner end of each magnetic plate of the magnetic plate pair, the triangular member directs flux produced by rotation of the rotor toward the stator. [0009] In another aspect of the invention, an interior permanent magnet rotor comprises a rotor being disposed for rotation within, and relative to the ring-shaped stator, the rotor comprises a shaft rotatably supported by the housing; a magnetic plate pair disposed about an outer circumference of the rotor, wherein each magnetic plate of the magnetic plate pair has opposing sides that extend from the outer circumference toward the shaft, the opposing sides are bounded by an inner end of each magnetic plate; a triangular member disposed between the magnetic plate pair and the shaft, the triangular member having a flat surface mated to each inner end of each magnetic plate of the magnetic plate pair, the triangular member directs flux produced by rotation of the rotor toward the stator. [0010] These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0011] The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: [0012] FIG. 1 shows a motor in accordance with the invention; [0013] FIG. 2 shows a rotor in accordance with the invention; [0014] FIG. 3 illustrates a magnetic plate pair of the rotor in accordance with the invention; [0015] FIG. 4 illustrates specific geometries of the rotor in accordance with the invention; [0016] FIG. 5 shows a relationship for torque constant (K t ) saturation by comparing results with conventional sintered magnets versus exemplary designs in accordance with the invention; and [0017] FIG. 6 shows an exemplary relationship for average torque by comparing results with conventional sintered magnets versus exemplary designs in accordance with the invention. DETAILED DESCRIPTION [0018] Referring now to the Figures, where the invention will be described with reference to specific embodiments without limiting the same, FIG. 1 illustrates a cross-sectional view of an IPM motor 100 . As shown in FIG. 1 , the IPM motor 100 comprises a housing 102 , a ring-shaped stator 104 fixed in the housing 102 and a rotor 106 . The ring-shaped stator 104 may have a coil suitable for conducting an electrical current. In this embodiment, the coil of the stator 104 is formed by plurality of cores 108 . The rotor 106 includes a shaft 110 rotatably attached to the housing 102 . The electrical current in the coil of the ring-shaped stator 104 may cause rotation of the shaft 110 relative to the ring-shaped stator 104 . The IPM motor 100 , including the ring-shaped stator 104 and the rotor 106 , may be cylindrically shaped or disk shaped, in some embodiments. [0019] FIG. 2 illustrates the rotor 106 in accordance with some embodiments of the invention. In addition to the shaft 110 , the rotor 106 comprises at least one magnetic plate pair 202 . The magnetic plate pair 202 may be disposed about an outer circumference 203 of the rotor 102 . In this embodiment, the outer circumference 203 is spaced inward toward the shaft 110 , leaving a space between the outer surface of the rotor 106 and an outer end of a magnetic plate of the magnetic plate pair 202 . [0020] In the embodiment shown in FIG. 2 , a plurality of magnetic plate pairs 204 are circumferentially spaced about the rotor. Although six magnetic plate pairs are illustrated as the plurality of magnetic plate pairs 204 for purposes of description, any number of magnetic plate pairs may exist in the rotor 106 , such as three, four, ten, etc. [0021] Adjacent magnetic plate pairs may alternate in magnetic polarity. For example, a first magnetic plate pair may have a north magnetic polarity, where second magnetic plate pair may have a south magnetic polarity. The alternation of magnetic polarity of the plurality of magnetic plate pairs may continue throughout the rotor. Furthermore, adjacent magnetic plate pairs may be spaced by a pitch defined by a distance P. As shown in FIG. 2 , the plurality of magnetic plate pairs 204 are approximately equidistantly spaced about the rotor 106 , so the pitch P is approximately equal between magnetic pairs. [0022] In some embodiments, the plurality of magnetic plate pairs 204 are anisotropic injected molded magnets. The rotor 106 can be manufactured by using powder metal, a casting process, or any other suitable metal. [0023] FIG. 3 illustrates the magnetic plate pair 202 of the rotor 106 in more detail. The magnetic plate pair 202 has magnetic plates 304 , 305 . In this embodiment, magnetic plates 304 , 305 each have opposing convex sides 306 , 308 that extend from the outer circumference toward the shaft 110 . The opposing convex sides 306 , 308 of magnetic plates 304 , 305 are bounded by the outer ends 310 , 311 and an inner ends 312 , 313 of the respective magnetic plates 304 , 305 . [0024] In some embodiments, the magnetic plates 304 , 305 may be injection-molded, or filled by using an injection molding process. The invention is not limited to an injection molding process. In addition, in some embodiments, the magnetic plates 304 , 305 may be compressed magnets. The magnetic plates 304 , 305 may represent any magnetic plates of the plurality of magnetic pairs. [0025] In this embodiment, the magnetic plates 304 , 305 are oriented to form an angle α between magnetic plates of the magnetic plate pair. The angle α may increase as a radial distance from the shaft 110 increases (e.g. distance from the inner end toward the outer end of the magnetic plate pair). [0026] As shown in FIG. 3 , the rotor 106 may further comprise a plurality of triangular members. In this embodiment, a triangular member 314 of the plurality of triangular members is disposed between the magnetic plate pair 202 and the shaft. The triangular member 314 has a flat surface mated to inner ends 312 , 313 of the magnetic plates 304 , 305 of the magnetic plate pair 202 . Accordingly, the flat surface of the triangular member 314 may physically contact each the magnetic plates 304 , 305 of the magnetic plate pair 202 . [0027] The flat surface of the triangular member 314 may be bounded by a second side and third side of the triangular member. The second side and third side of the triangular member may be adjacent to one another, and extend from the flat surface toward the shaft 110 , forming an apex of the triangular member 314 . The apex of the triangular member may extend to the shaft, or as shown in FIG. 2 , the apex may be spaced from the shaft. The spacing of the apex from the shaft leaves a space formed by inner circumference to the shaft. [0028] The plurality of triangular members may be made of any non-magnetic material including but not limited to plastic, aluminum, and/or glue. Alternatively, the plurality of triangular members may be an air gap formed by the rotor 106 and the inner ends 312 , 313 of the magnetic plate pair 202 . The composition of triangular members with the rotor 106 may vary within the rotor 106 , or be consistent within the rotor 106 . [0029] The plurality of triangular members are configured to decrease flux leakage by directing flux away from the shaft 110 . Thus, the flux is concentrated radially outward, while softening torque pulsations of the motor. [0030] FIG. 4 illustrates specific geometries of the rotor 106 . A magnet inner arc diameter (IAD), magnet outer arc diameter (OAD) are defined. A minimum distance between the magnet and the outer rotor radius is defined by WEB. An outer magnet thickness (OMT), inner rib thickness (IRT), and an angular distance in between two plates of a single magnetic pole is defined by α. These parameters shape the non-magnetic material, reducing cogging and ripple torque, those parameters are also shown below. An outer non-magnetic thickness (ONMT), an inner non-magnetic thickness (INMT) and non-magnetic width (NMW) may define a triangular member that decreases flux leakage, concentrating the flux radially outward while softening torque pulsations of a motor. [0031] FIG. 5 shows relationships for torque constant (K t ) saturation by comparing results with conventional sintered interior permanent magnets versus exemplary designs in accordance with the invention. In an exemplary embodiment, the injection molded IBPM shows greater K t relative to sintered interior permanent magnet motors. [0032] FIG. 6 shows relationships for average torque (T avg ) by comparing results with conventional sintered interior permanent magnets versus exemplary designs in accordance with some embodiments of the invention. In an exemplary embodiment, the injection molded IBPM shows greater average torque relative to sintered interior permanent magnet motors. [0033] While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description.

An interior permanent magnet motor includes a housing, a ring-shaped stator fixed in the housing and having a coil which generates a magnetic field when a voltage is applied, a rotor being disposed for rotation within, and relative to the ring-shaped stator. The rotor includes a shaft rotatably supported by the housing, a magnetic plate pair disposed about an outer circumference of the rotor. A triangular member is disposed between the magnetic plate pair and the shaft. The triangular member having a flat surface mated to each inner end of each magnetic plate of the magnetic plate pair. The triangular member directs flux produced by rotation of the rotor toward the stator.

FIELD OF THE INVENTION This invention relates to internal combustion engines, including but not limited to recirculation of crankcase gases into the intake system of an engine. BACKGROUND The present invention relates to a breather system for a crankcase of an internal combustion engine of the type which separates oil drops or mist from blow-by gases. The blow-by gases are routed to the intake air line of an engine to eliminate the discharge of combustion gases into the environment. Separated oil is routed back to the oil pan. Ideally, the pressure within an internal combustion engine crankcase should be maintained at a level equal to or slightly less than atmospheric pressure to prevent external oil leakage through the various gasketed joints, such as that between the valve cover and the cylinder head. Combustion gases are generated during the operation of an internal combustion engine. A small amount of these gases leaks past the piston seals, valve stems seals, and turbochargers of the internal combustion engine. Because of the “blow-by” gases, the crankcase pressure will inherently rise, promoting leakage of oil from the crankcase. These gases, commonly referred to in the art as “blow-by” gases, need to be released. Environmental considerations suggest that the blow-by gases in the crankcase be vented back to the combustion chamber rather than being released to the atmosphere. Accordingly, it is known to scavenge the crankcase of blow-by gases by connecting the crankcase to the engine air intake. Blow-by gases that are released from the crankcase carry combustion by-products and oil mist caused by splashing of the engine's moving components within the crankcase and the oil pan. It is known to substantially remove the oil mist from the blow-by gas prior to introduction into the intake air system. An apparatus that removes oil mist from blow-by gases is commonly referred to as a “breather.” Known breathers include breathers that include a stack of conical disks that spin at a high speed to fling heavier oil against a wall of the breather and allow gas to pass though the breather. Centrifuge type separators are disclosed for example in U.S. Pat. Nos. 7,235,177 and 6,139,595. Other types of breathers include filters such as described in U.S. Pat. Nos. 6,478,019, 6,354,283; 6,530,969; 5,113,836; swirl chambers or cyclone separators, such as described in U.S. Pat. Nos. 6,860,915; 5,239,972; or impactors, such as described in U.S. Pat. Nos. 7,258,111; 7,238,216 5,024,203. Each type of breather has advantages and limitations. The present inventor has recognized that it would be desirable to provide a breather system that is more economical to produce and more effective in operation than existing breather systems. SUMMARY An exemplary embodiment of the invention provides a breather system for a crankcase of an internal combustion engine. The breather system includes a gas compressor having a compressor inlet and a compressor outlet. The gas compressor is configured to elevate the pressure of blow-by gas received into the inlet and to discharge elevated pressure gas from the compressor outlet. An inlet conduit is arranged to connect the crankcase to the compressor inlet. At least one gas-oil separator includes a gas inlet for receiving the elevated pressure gas from the compressor, an oil outlet for discharging oil separated from the elevated pressure gas, and a gas outlet for discharging a gas having a reduced oil content. The at least one outlet conduit connects the compressor outlet to the gas inlet. The at least one gas-oil separator can comprise a swirl chamber separator in series with an impact separator. The swirl chamber separator and the impact separator can be cast as a unitary housing. The oil outlet can be flow-connected to return the separated oil to the crankcase. According to an exemplary embodiment, the gas outlet is flow connected to an air intake for the engine to re-circulate the gas discharged from the at least one gas-oil separator. According to another aspect of the disclosed embodiment, the at least one gas-oil separator includes a gas outlet and a bypass conduit flow connected between the gas outlet and the compressor inlet. The compressor can be a piston pump type of compressor or other known type of compressor. The disclosed embodiment provides a method for separating oil from crankcase gas from an internal combustion engine, including the steps of: receiving crankcase gas outside of the crankcase and into a compressor; pressurizing the crankcase gas using the compressor; channeling the pressurized crankcase gas into a gas-oil separator; separating oil from the crankcase gas in the gas-oil separator; and returning the separated oil from the gas-oil separator to the crankcase. The method can also include the step of directing crankcase gas from the gas-oil separator to a combustion air intake of the engine. The method can also include the step of: if the capacity of the compressor exceeds the crankcase gas production, directing gas flow from the gas-oil separator to the compressor. Numerous other advantages and features of the present invention will be become readily apparent from the following detailed description of the invention and the embodiments thereof, and from the accompanying drawing. BRIEF DESCRIPTION OF THE DRAWING The FIGURE is a schematic diagram of a breather system of the present invention. DETAILED DESCRIPTION While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated. The FIGURE is a schematic diagram that illustrates an embodiment of an engine breather system 10 according to the present invention. The system 10 is associated with an engine 20 which could be a diesel engine, such as a diesel engine for a long haul truck. The diesel engine can be normally aspirated or turbocharged. The engine 20 includes a crankcase 22 having an upper engine internal volume 23 partly defined by a valve cover 24 . The upper engine internal volume is generally in fluid communication with all the blow-by gases within the crankcase. The system 10 includes a gas compressor or pump 26 that includes a piston or a rotary impeller (not shown) or other fluid actuating device that can be belt driven, gear driven or otherwise driven by the engine 20 . Alternately the compressor could be driven by another power source. A number of compressor or pump types can be used, in addition to the standard piston pump, such as a gear pump, a gear-rotor pump, a vane pump, a rotary screw pump, or a diaphragm pump. According to one embodiment, the compressor would be rated at less than 50 PSI and to maintain a relatively small size, would be capable of being driven at speeds up to 10,000 RPM. A typical maximum bow-by gas flow rate for the compressor is 700 CFH (ft 3 /hour). The gas compressor 26 includes an inlet 26 a that is in fluid communication via a conduit 28 with the internal volume 23 by a connection to the valve cover 24 . An outlet 26 b of the compressor is in fluid communication with an inlet 50 a of a swirl chamber separator or cyclone separator 50 . Such a cyclone separator is described for example in U.S. Pat. Nos. 6,860,915 and 5,239,972, herein incorporated by reference. An outlet 50 b of the swirl chamber is in fluid communication with in inlet 60 a of an impactor or impact separator 60 . such an impact separator is described for example in U.S. Pat. Nos. 7,258,111; 7,238,216 and 5,024,203. An outlet 60 b of the impactor 60 is in fluid communication with a pressure regulator 70 . The pressure regulator maintains a desired gas pressure within the impact separator and swirl chamber separator by varying the gas flow restriction through the regulator. Oil that is separated from the gas in the swirl chamber 50 drains through an oil outlet 50 c at a bottom of the swirl chamber 50 . Oil that is separated from the gas in the impactor 60 drains through an oil outlet 60 c at a bottom of the impactor 60 . The outlets 50 c , 60 c can be small drain orifices. The combined oil from the outlets 50 c , 60 c is collected in a conduit or conduits 80 and returned to the crankcase 22 . The compressor 26 sucks blow-by gases from the crankcase 22 and compresses the blow-by gases to a pre-selected pressure, which may be below 50 PSIG. The blow-by gases are delivered into the swirl chamber 50 and then into the impactor 60 at elevated pressure. Each of the swirl chamber 50 and then into the impactor 60 separate some oil from the oil entrained blow-by gases. The pressure regulator 70 can be set to a desired working pressure to maintain elevated pressures within the components 50 , 60 and allow cleaned gas to pass into a discharge conduit 90 that can either be directed to atmosphere or can be redirected to the engine intake manifold for a normally aspirated engine or to the turbocharger compressor for a turbocharged engine. Alternately, with a sufficient arrangement of valves, the discharge conduit could be directed into the exhaust system. Pressure pulses from the compressor, in the form of a piston pump compressor, aid in the separation of oil and gas from the blow-by gases, because of the instantaneous high velocity of blow-by gases that enter the impactor. According to one embodiment of the invention, the size of the compressor should be large enough to outpace the amount of blow-by gases that are drawn into the compressor, which may be as high as 700 CFH (ft 3 /hour). If the compressor is of the piston type with one-way valve or valves, the piston should be orientated in a manner where the outlet valve is at the lowest point, below the piston so that any condensed oil can drain through the drain orifice and back into the engine to prevent oil from pooling and overwhelming the system when it leaves the compressor. The swirl chamber 50 and impactor 60 typically have no moving components and the swirl chamber 50 and impactor 60 can be cast as part of a common or unitary housing. Additionally, impactors of current design typically require high gas velocity to function. Therefore, small orifices are typically required but are restrictive such as to require a significant pressure drop. However, according to the disclosed embodiment, the compressor elevates the pressure of the blow-by gases to push the air through smaller orifices at higher velocity, i.e., more pressure drop is available. Furthermore, the high velocity of the cleaned blow-by gases from the impactor may reduce condensation and possible ice buildup in the discharge conduit 90 . A screen (not shown) can be used at each of the oil outlets 50 c , 60 c to protect the outlets from clogging with debris. The oil drain diameters for the outlets 50 c, 60 c can be sized in a manner that allows the system 10 to keep up with the amount of oil that is being separated from gas but not allow excessive loss of pressure by venting gas. During high engine speed and low power operation, the outlets 50 c , 60 c will normally be clear of oil and gas pressure may vent through the outlets 50 c , 60 c to the crankcase, which will then vent back to the compressor. This is not detrimental to the system 10 or to engine operation during these engine operating conditions. A bypass conduit 110 can be provided to direct gas from the low pressure output of the regulator 70 at the discharge conduit 90 to a low pressure compressor intake at the conduit 28 . When engine speed is high and the load is low, the compressor will be oversized for the amount of blow-by gas generated, which would result in formation of a vacuum within the engine. To avoid this condition, the bypass conduit 110 can be used to re-circulate cleaned blow-by gas from the discharge conduit 90 back into the compressor 26 where it is re-introduced to the separators 50 , 60 , re-cleaned and proper crankcase pressure can be maintained. If under unusual circumstances blow-by volume from the engine exceeds compressor capacity, the excess blow-by gas will bypass the compressor through the bypass conduit 110 and discharge through the discharge conduit 90 . Parts List 10 engine breather system 20 engine 22 crankcase 23 upper engine internal volume 24 valve cover 26 pump or compressor 28 conduit 50 swirl chamber or cyclone separator 50 a swirl chamber gas inlet 50 b swirl chamber gas outlet 50 c swirl chamber oil outlet 60 impact separator or impactor 60 a impactor gas inlet 60 b impactor gas outlet 60 c impactor oil outlet 70 pressure regulator 80 conduits 90 discharge conduit 110 bypass conduit From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.

A breather system for a crankcase of an internal combustion engine includes a gas compressor configured to elevate the pressure of crankcase blow-by gas. At least one gas-oil separator receives gas with entrained oil from the compressor, separates oil from the gas and discharges cleaned gas. The oil is re-circulated back to the crankcase. The cleaned gas is either discharged through the engine exhaust system or re-circulated back into the engine combustion air intake. A bypass conduit allows cleaned gas to be re-circulated from the gas-oil separator outlet to the compressor inlet to balance the blow-by production with the capacity of the compressor.

CROSS REFERENCES TO RELATED APPLICATIONS [0001] This Application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Patent Application Ser. No. 61/419,936 filed Dec. 6, 2010, which is incorporated herein by reference in its entirety as if fully set forth herein. STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT [0002] This invention was made with government support under Grant No. 6-32430 awarded by the National Institutes of Health. The government has certain rights in the invention. TECHNICAL FIELD [0003] The claimed invention relates to a method and system for enhancing the intelligibility of sounds relative to background noise and has particular application for listening devices such as hearing aids, bone conductors, cochlear implants, assistive listening devices, and active hearing protectors. Embodiments of the invention generally relate to hearing assistance devices and in particular to methods and apparatus for improved noise reduction for hearing assistance devices. BACKGROUND TO THE INVENTION [0004] One of the most common complaints in hearing impaired subjects is reduced speech intelligibility in noisy environments. In realistic listening situations, speech is often contaminated by various types of background noise. Noise reduction algorithms for digital hearing aids have received growing interest in recent years. Although a lot of research has been performed in this area, a limited number of techniques have been used in commercial devices. One main reason for this limitation is that many noise reduction techniques perform well in the laboratory, but lose their effectiveness in everyday life listening conditions. [0005] Generally, three types of noise fields are investigated in multi-microphones speech enhancement studies: (1) incoherent noise caused by the microphone circuitry, (2) coherent noise generated by a single well-defined directional noise source and characterized by high correlation between noise signals (3) diffuse noise, which is characterized by uncorrelated noise signals of equal power propagating in all directions simultaneously. Performance of speech enhancement methods is strongly dependent on the characteristics of the environmental noise they are tested in. Hence, the performance of methods that work well in the diffuse field starts to degrade when tested in coherent noise fields. [0006] Modern hearing assistance devices, such as hearing aids typically include a digital signal processor in communication with a microphone and receiver. Such designs are adapted to perform a great deal of processing on sounds received by the microphone. These designs can be highly programmable and may use inputs from remote devices, such as wired and wireless devices. [0007] Numerous noise reduction approaches have been proposed. However, noise reduction algorithms can result in decreased intelligibility and audibility of speech due to speech distortion from the application of the noise reduction algorithm. [0008] Accordingly, there is a need for methods and apparatus for improved noise reduction for hearing assistance devices. Such methods should address and reduce speech distortion to enhance intelligibility and audibility of the speech. SUMMARY OF THE INVENTION [0009] An embodiment of the invention provides an algorithm is capable of suppressing noise captured by two close microphones. The method is based on the coherence function of noisy signals at the two channels. Coherence is a complex frequency function and indicates how two signals are correlated at each frequency bin. Traditionally, magnitude of the coherence function is used as criterion for determining the possibility of presence of speech at each component. The claimed method is based on real and imaginary part of this function and suppresses background noise assuming that the received signal originates from the front (desired target signal) or from other range of angles (noise signals). [0010] Another embodiment of the invention provides a coherence-based technique capable of dealing with coherent noise, and applicable for hearing aid and cochlear implant devices. [0011] Disclosed herein, are methods and apparatuses for improved noise reduction for hearing assistance devices. In various embodiments, a hearing assistance device includes a microphone and a processor configured to receive signals from the microphone. The processor is configured to perform noise reduction which adjusts maximum gain reduction as a function of signal-to-noise ratio (SNR), and which reduces the strength of its maximum gain reduction for intermediate signal-to-noise ratio levels to reduce speech distortion. In various embodiments, the hearing assistance device includes a memory configured to log noise reduction data for user environments. The processor is configured to use the logged noise reduction data to provide a recommendation to change settings of the noise reduction, in an embodiment. In various embodiments, the processor is configured to use the logged noise reduction data to automatically change settings of the noise reduction. [0012] In various embodiments of the present subject matter, a method includes receiving signals from a hearing assistance device microphone in user environments and adjusting maximum gain reduction as a function of signal-to-noise ratio to perform noise reduction. Various embodiments of the method include reducing the strength of the maximum gain reduction for intermediate signal-to-noise ratio levels to reduce speech distortion. [0013] The Summary is an overview of some of the teachings of the present application and not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details about the present subject matter are found in the detailed description and appended claims. The scope of the present invention is defined by the appended claims and their legal equivalents. BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIGS. 1A to 1D shows a comparison between the true SNR at the front microphone and its predicted values by the proposed algorithm, for four different frequencies. The noise source is located at 90° azimuth and SNR=0 dB (speech-weighted noise); [0015] FIG. 2 illustrates a block diagram of the proposed two-microphone speech enhancement technique; [0016] FIG. 3 shows a block diagram of the two microphone adaptive beamformer used for comparative purposes; [0017] FIGS. 4A-4D show SRT results of seven normal-hearing subjects in the different noise configurations. Numbers indicate the SNR (dB) required to understand 50% of the words correct. Error bars indicate standard deviation; [0018] FIG. 5 shows SRT improvements of the beamformer and proposed algorithm over the DIR in the different noise configurations. Error bars indicate standard deviations; [0019] FIG. 6 shows PESQ scores obtained in different noise scenarios; and [0020] FIGS. 7A-7D illustrate spectrograms of the clean speech signal (top left) and DIR signal (top right). Speech is degraded by interfering speech (SNR=0 dB) located at 90° azimuth. Bottom left panel shows enhanced signal by the beamformer and bottom right panel shows enhanced signal by the proposed coherence-based algorithm. The target IEEE sentence was “Glue the sheet to the dark blue background” uttered by a male speaker and the masker sentence was “He is completing his apprenticeship at the funeral home” uttered by a female speaker. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS [0021] The following detailed description of the present subject matter refers to subject matter in the accompanying drawings which show, by way of illustration, specific aspects and embodiments in which the present subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present subject matter. References to “an”, “one”, or “various” embodiments in this disclosure are not necessarily to the same embodiment, and such references contemplate more than one embodiment. The following detailed description is demonstrative and not to be taken in a limiting sense. The scope of the present subject matter is defined by the appended claims, along with the full scope of legal equivalents to which such claims are entitled. [0022] An embodiment of the invention shows how the coherence function can be used as a criterion for noise reduction. [0023] Coherence is a function of frequency with values between zero and one and an indicator of how well two signals correlate to each other at each frequency. Assume two microphones are placed in a noisy environment in which the noise and target speech signals are spatially separated. In this case, the noisy speech signals, after delay compensation, can be defined as [0000] y i ( m )= x i ( m )+ n i ( m ) ( i= 1, 2)   (1) where i denotes the microphone index, m is the the sample-index and x i (m) and n i (m) represent the (clean) speech and noise components in each microphone, respectively. [0025] After applying a short-time discrete Fourier transform (DFT) on both sides of the above equation, it can be expressed in the frequency domain as [0000] Y i (ω i , k )= X i (ω i , k )+ N i (ω i , k ) ( i= 1, 2)   (2) where k is the frame index, ω i =2πl/L and l=0, 1, 2, . . . , L−1, where L is the frame length in samples. In subsequent equations, the subscript “1” has been omitted for better clarity and ω is referred to as the angular frequency. [0027] The coherence function is a measure of linear relationship between two random processes. It shows the degree of correlation between the components at a particular frequency. Coherence is a complex valued function and between two arbitrary signals is defined as [0000] Γ u 1  u 2  ( ω , k ) = Φ u 1  u 2  ( ω , k ) Φ u 1  u 1  ( ω , k )  Φ u 2  u 2  ( ω , k ) ( 3 ) where Φ uv (ω, k) denoes the cross-power spectral density (CSD) defined as Φ uv (ω, k)=E[U (ω, k)V*(ω, k)], and Φ uu (ω, k) denotes power spectral density (PSD) defined as Φ uu (ω, k)=E[(U (ω, k)) 2 ]. The coherence function assumes a value close to 1 if the two signals are correlated and a value close to 0 if they are uncorrelated. The coherence function can be analytically modeled based on the noise filed. In a diffuse noise field, the coherence function is real-valued and its value increases as the distance between two microphone decreases. Coherent noise field is generated from a single well-defined directional sound source, and for two closely-spaced omnidirectional microphones captured signals are perfectly coherent except for a time delay. [0000] Γ u1u2 (ω)= e jωf s (d/c)cos θ   (4) where θ is the angle of incidence, f s is the sampling frequency, c≅340 m/s is the speed of sound and “d” the microphone spacing. [0030] To describe the proposed SNR the below equation is used: [0000] Γ y   1  y   2 =  Γ x   1  x   2 ( SNR 1 1 + SNR 1  SNR 2 1 + SNR 2 ) +  Γ n   1  n   2 ( 1 1 + SNR 1  1 1 + SNR 2 ) ( 5 ) where Γ y1y2 , Γ x1x2 and Γ n1n2 denote the coherence function between noisy input, clean speech and noise signals at two microphones respectively, and SNR 1 and SNR 2 denote local SNR values at the two channels. In the above equation the ω and k indices were omitted for sake of clarity. Since the distance between microphones in the present configuration is fairly small (˜20 mm) it can be assumed that SNR1≅SNR2. Therefore, the last equation can be modified as follows [0000] Γ ^ y 1  y 2 ≃ Γ x 1  x 2  S  N ^  R 1 + S  N ^  R + Γ n 1  n 2  1 1 + S  N ^  R ( 6 ) where S{circumflex over (N)}R is an approximation to both SNR1 and SNR2. After applying (4) the last equation can be rewritten as follows; [0000] Γ ^ y 1  y 2 ≃ [ cos   ( ω   τ ) + j   sin   ( ω   τ ) ]  S  N ^  R 1 + S  N ^  R + [  cos   ( ω   τ   cos   θ ) + j   sin   ( ω   τ   cos   θ ) ]  1 1 + S  N ^  R ( 7 ) where τ=f s (d/c). By taking the real part of the equation, [0000] ℜ = S  N ^  R 1 + S  N ^  R  cos   ω . + 1 1 + S  N ^  R  cos   α ( 8 ) where is the real part of Γ y1y2 , {dot over (ω)}=ωτ and α={dot over (ω)} cos θ. [0035] By rearranging terms in the previous equation, the following equation is obtained: [0000] S  N ^  R = cos   α  - ℜ ℜ - cos   ω . ( 9 ) [0036] By taking the imaginary part of (7) the following equation is obtained [0000] ( 10 ) where is the imaginary part of Γy 1 y 2 [0038] By rearranging the terms in the last equation, the following equation is obtained: [0000] S  N ^  R = sin   α - - sin   ω . ( 11 ) [0039] Since the right-hand sides of (9) and (11) are equal, S{circumflex over (N)}R can be removed and combined into a single equation as follows: [0000] ( −sin {dot over (ω)})cos α+(cos {dot over (ω)}− )sin α+ sin {dot over (ω)}− cos {dot over (ω)}=0   (12) [0040] In the last equation, the only unknown parameter is α. By introducing the following variables: [0000] { A = - sin   ω . B = cos   ω . - C =   sin   ω . -   cos   ω . ( 13 ) (12) can be rewritten as: [0000] A cos α=− B sin α− C   (14) [0042] By raising both sides of the last equation to the power of two, and using the fact that cos 2 α=1−sin 2 α, (14) can be substituted by the following quadratic equation: [0000] ( A 2 +B 2 )sin 2 +2 B C sin α+( C 2 −A 2 )=0   (15) which yields two solutions, as shown below: [0000] sin   α = - BC  ± B 2  C 2 - ( C 2 - A 2 )  ( A 2 + B 2 ) A 2 + B 2 ( 16 ) [0044] The last equation can be rewritten in a simpler form as follows: [0000] sin   α = - BC  ±  A   A 2 + B 2 - C 2 A 2 + B 2 ( 17 ) [0045] As is shown in Appendix A, the inside of the square root is always positive, and is equal to the square of: [0000] T= 1− cos {dot over (ω)}− sin {dot over (ω)}  (18) [0046] One solution of sin α in (17) is trivial and leads to sin α=sin {dot over (ω)} and therefore from (11), S{circumflex over (N)}R=1, which is not possible since both PSDs of speech and noise signals are always positive. After replacing A, B and C by their actual values and some manipulations it can be shown that the solution with negative root is the correct one when T and A have same signs, otherwise positive root will lead to the correct solution. After computing the value of sin α, we can calculate the S{circumflex over (N)}R using (11). [0047] To verify the validity of the above SNR estimation algorithm, FIG. 1 shows a comparison between the true SNR values at the front microphone and the approximation obtained using the proposed algorithm. SNR values shown in FIGS. 1A to 1D correspond to a sentence (produced by a male speaker) corrupted by a speech-weighted noise located at 90°. A comparison was made for four different frequencies. As is evident from the figure, in both low and high frequency ranges, the estimated SNR values follow the true SNR values quite well. To assess how close the approximation of SNR is to the true one, we quantify the errors using root mean square error (RMSE) defined as follows: [0000] RMSE SNR (ω)=√{square root over ( E [(SNR(ω)−S{circumflex over (N)}{square root over ( E [(SNR(ω)−S{circumflex over (N)}R(ω)) 2 ])}  (19) [0048] In the above equation the expected value was computed over all frames. This measure assesses the distance between the true and predicted SNR, and lower values of the error indicate higher accuracy of the approximation. Table I below shows results of the above measures averaged over 10 sentences. For this evaluation, speech-weighted noise was used at 90° and SNR was measured in dB. [0000] TABLE I Frequency Input SNR RMSE SNR (dB) 500 Hz −5 dB 2.72 1 kHz −5 dB 3.45 2 kHz −5 dB 4.25 4 kHz −5 dB 4.90 500 Hz 0 dB 4.13 1 kHz 0 dB 4.97 2 kHz 0 dB 4.75 4 kHz 0 dB 4.91 [0049] It has previously been shown that a priori SNR based approach leads to the best subjective results. In the present invention, the Wiener filter is defined as: [0000] G  ( ω , k ) = S  N ^  R   ( ω , k ) S  N ^  R   ( ω , k ) + 1 ( 20 ) [0050] The implementation details of the proposed coherence-based method are described below. In an embodiment of the invention, the two signals captured by the microphones are first processed in 20 ms frames with a Harming window and a 50% overlap between adjacent frames. Based on the short-time Fourier transform of the two signals calculated, the PSDs and CSD are computed using the following two first order recursive equations: [0000] Φ y1y2 (ω, k )=λΦ y1y2 (ω, k− 1)+(1−λ)| Y i (ω, k )| 2 ( i= 1, 2)   (21) [0000] Φ y1y2 (ω, k )=λΦ y1y2 (ω, k− 1)+(1−λ) Y 1 (ω, k ) Y 2 *(ω, k )   (22) where (−)* denotes the complex conjugate operator and λ is a forgetting factor, set between 0 and 1. In the present invention, A is set to 0.6. FIG. 2 shows the procedure of speech enhancement with the proposed method in a block diagram. As shown in the block diagram, a software directional microphone is created by the two omnidirectional microphones. The directional microphone parameter is δ(ω)=αe −jωΔ 0 , where a and Δo are set so as to obtain a hypercardioid polar diagram in anechoic conditions (null at 110°). This approach is referred to as directional microphone (DIR) approach. To obtain an enhanced signal, a suppression function is applied to the Fourier transform of the signal corresponding to DIR. To reconstruct the enhanced signal in the time-domain, an inverse FFT is applied and the signal is synthesized using the overlap-add (OLA) method. [0052] In an embodiment of the invention, the suggested technique was tested inside an almost anechoic room (T 60 ≅80 ms). Generally, in a reverberant environment, the noise signals at the two microphones will be less correlated. In such conditions, the environmental noise gets characteristics of the diffuse noise field, and therefore equation (4) does not hold anymore. Although considering a small microphone spacing, it can still be assumed that the noise signals are highly correlated for a wide range of frequencies, the method loses its ability to suppress the noise components that are not highly correlated. The problem of dealing with uncorrelated noise components has been also investigated for beamformers. It has been suggested that by passing the output of beamformer through a post-filter, such as a Wiener filter, uncorrelated noise components can be dealt with that can not be easily suppressed by beamformers. WORKING EXAMPLES A. Test Materials and Subjects [0053] Sentences taken from the IEEE database corpus (designed for assessment of intelligibility) were used. These sentences (approximately 7-12 words) are phonetically balanced with relatively low word-context predictability. The root-mean-square amplitude of sentences in the database was equalized to the same root-mean-square value, which was approximately 65 dBA. The sentences were originally recorded at a sampling rate of 25 kHz and downsampled to 16 kHz. [0054] Two types of noise (speech-weighted and competing talker) were used as maskers. The speech-weighted noise used, was adjusted to match the average long-term spectrum of the speech materials. The competing talker sentences used as maskers were taken from the AzBio corpus. The database was developed to evaluate the speech perception abilities of hearing-impaired listeners and CI users. The sentence corpus includes 33 lists, each containing 20 sentences recorded from two female and two male speakers. [0055] Seven normal hearing listeners, all native speakers of American English, participated in the listening test. Their ages ranged from 18 to 23 years (mean of 20 years). The listening tests were conducted in a double-walled sound-proof booth via Sennheiser HD 485 headphones at a comfortable level. B. Methods and Noise Configurations [0056] The noisy stimuli at the pair of microphones were generated by convolving the target and noise sources with a set of HRTFs (head-related transfer functions) measured inside a mildly reverberant room (T 60 ≅80 ms) with dimensions 3.8×4.33×2.2 m 3 (length×width×height). [0057] The HRTFs were measured using identical microphones to those used in modern hearing aids. The noisy sentence stimuli were processed using the following conditions: (1) the software directional microphone (DIR), used as a baseline, (2) an adaptive beamformer algorithm and (3) the coherence-based algorithm of the present invention. [0058] The adaptive algorithm against which the present method was compared is the two-stage beamformer, which has been used widely in both hearing aid and cochlear implant devices. The two-stage adaptive beamformer is an extension of the GSC technique. A block diagram of the beamformer is depicted in FIG. 3 . In the implementation of the beamformer, the adaptive filter has 32 taps, and the coefficients are updated by a Normalized-Least Mean Square (NLMS) procedure. The FIR filter 10 coefficients were fixed to give a specific look direction to the two-stage adaptive beamformer, Δ 1 and Δ 2 are additional delays and their values were set to half of the size of the filters. [0059] The test was carried out in four different noise scenarios. In one of them, a single noise source generating speech-weighted noise was placed at 45°. In the other three noise conditions, competing talkers are used as interfering sources: (a) one talker at 90°, (b) two talkers at (90°, 180°), and (c) two talkers at (90°, 270°). The talker at 90° is a female speaker and the other talker is a male speaker. [0060] In order to investigate speech intelligibility obtained by the different algorithms, the SRT measurement technique was used. At the start of each SRT measurement, the subject listens to noisy stimuli with very low SNR. Then, he/she repeats as many words as possible. After each response, the same target sentence and interferer combination is replayed with +4 dB shift in SNR repeatedly, until the subject reproduced more than half of the sentence correctly. From that point, actual SRT measurement begins using a one-down/one-up adaptive SRT technique targeting 50% correct speech reception. In the present implementation, SNR step size is 2 dB and SRT was determined by averaging the SNR level presented in last eight trials. [0061] SRT scores of the different methods for all seven listeners are presented in FIGS. 4A 4 D. FIG. 5 shows the improvements in SRT, obtained with the beamformer and proposed algorithm over the DIR system. As is apparent from FIG. 5 , both the beamformer and proposed technique yield more than 5 dB improvement, when speech-weighted noise is located at 45°. [0062] However, in contrast to the algorithm presented herein, the beamformer does not provide a noticeable benefit over the DIR system in the noise scenarios with competing talkers. As it is also clear from the figure the proposed algorithm shows more than 5 dB improvement for the different noise configurations with competing talkers, while the improvement with the bearnformer is about 2 dB. The reason for the poor performance of the beamformer with competing talker is that the beamformer relies on VAD decisions, and when speech is detected by the VAD the adaptation is turned off. In fact, the adaptive filter of the beamformer cannot update its tap coefficients when competing talker interfering signals are present. Therefore, the beamformer applies no suppression to the input signals in this case. [0063] To assess the quality of speech signals, obtained by different methods, the Perceptual Evaluation of Speech Quality (PESQ) measure was used. This measure produces a score between 1.0 and 4.5, with larger values indicating better quality. In comparison to other conventional objective measures, the PESQ is the most complex to compute and is recommended for speech quality assessment of narrow-band handset telephony and speech codecs. A high correlation between the results of subjective listening tests and PESQ scores has been reported. To obtain the PESQ scores of different algorithms, two IEEE lists (20 sentences) were used per condition. FIG. 6 shows the resulting PESQ scores of the algorithms for the various noise scenarios, with input SNR equal to −5 dB and 0 dB. Clearly, the proposed coherence-based method outperforms DIR and the beamformer in all noise configurations involving competing talkers. In these cases, the proposed method achieved an average improvement of 0.8 relative to the scores of DIR and the beamformer. In the condition with speech-weighted noise at 45°, the scores of the beamformer are very close to those of our method. As can be seen in FIG. 6 , the PESQ scores are consistent with the subjective listening tests results. [0064] To observe the structure of the residual noise and speech distortion in the outputs of speech enhancement algorithms, sample spectrograms of clean and also those of the outputs of DIR, the beamformer and coherence-based method are presented in FIGS. 7A-7D . The figure shows that the background noise (competing talker) is more suppressed by the proposed method than by the beamformer, while the proposed method recovers the target speech signal components well. As it is also clear from the figure, the spectrograms of the beamformer is similar to that of DIR, and this confirms the fact that the beamformer almost keeps the input signal intact, when the interfering signal is a competing talker. These observations are in agreement with quality measurements results obtained with PESQ (see FIG. 6 ). [0065] An embodiment of the invention is directed to development of a novel dual-microphone coherence-based technique for SNR estimation. By applying a Wiener filter based on these SNR estimates, the corresponding noise reduction algorithm was proposed. Large improvements in both quality and intelligibility were obtained with the proposed algorithm relative to the directional microphone (used as a baseline) and conventional beamforming technique, in particular in situations where either single or multiple competing talkers were present. [0066] For humans, the problem of understanding one talker even if other persons are talking at the same time is called cocktail party phenomenon. Over the last decades, this problem has been mostly addressed in binaural noise reduction systems. However, less of dual microphone speech enhancement algorithms have been proposed to deal with competing talkers noise conditions. The main reason for this limitation is that dual microphone noise reduction algorithms usually need a noise estimator or VAD, since they require a prior knowledge of noise signal statistics. In general, estimating or detecting noise signals in adverse interference conditions, like competing talkers, is not a straightforward procedure. The SNR estimator we proposed in this paper, is a blind estimator, which does not rely on noise statistics. Based on the above discussion, the main advantage of our speech enhancement method is that, unlike the behavior of algorithms like beamformers, its performance is not dependent on the nature of the masker. Therefore, the improvement achieved by the proposed algorithm over the beamformer is more noticeable in low SNR and competing talkers scenarios, where noise estimation is a challenging problem. [0067] Finally, a major benefit of the proposed algorithm is the ease of implementation. Generally, not all of noise reduction algorithms are performing well in laboratory tests can be utilized in hearing aid devices, for the reasons such as limit of hardware size, the number and distance between microphones, computational speed and power consumption. The algorithm presented herein is relatively simple in terms of computation and can be implemented in real-time. In fact, the proposed suppression filter (gain function) can easily be achieved by computing the coherence function between the input signals and solving a quadratic equation obtained from the real and imaginary parts of the coherence function. Based on the above discussion and the results obtained on both subjective and objective tests, the proposed method can be a potential candidate for future use in commercial hearing aids and cochlear implant devices. APPENDIX A [0068] In this appendix, we prove that the term inside the square root in (17) is always positive. After replacing A, B and C by their actual values, we get the following expression for the term inside the square root of that equation: [0000] +sin 2 {dot over (ω)}−2 sin {dot over (ω)}+ +cos 2 {dot over (ω)}−2 cos {dot over (ω)}− cos 2 {dot over (ω)}− sin 2 {dot over (ω)}+2 sin {dot over (ω)} cos {dot over (ω)}  (23) [0000] which can be replaced by [0000] sin 2 {dot over (ω)}+cos 2 {dot over (ω)}+ (1−cos 2 {dot over (ω)})+ (1−sin 2 {dot over (ω)})−2 sin {dot over (ω)}−2 cos {dot over (ω)}+2 sin {dot over (ω)} cos {dot over (ω)}  (24) [0000] Using the fact that sin 2 {dot over (ω)}+cos 2 {dot over (ω)}=1, the last equation can be written as [0000] 1+ sin 2 {dot over (ω)}= sin {dot over (ω)}+ cos 2 {dot over (ω)}−2 cos {dot over (ω)}+2 sin {dot over (ω)} cos {dot over (ω)}  (25) [0000] the last equation is in fact (1− cos {dot over (ω)}− sin {dot over (ω)}) 2 , which is always positive. [0069] The dual-microphone algorithm of the present invention utilizes the complex coherence function between the input and yields a SNR estimator, computed based on the real and imaginary parts of the coherence function. The algorithm makes no assumptions about the placement of the noise sources and addresses the problem in its general form. The suggested technique was tested in a dual microphone application (e.g., hearing aids) wherein a small microphone spacing exists. Intelligibility listening tests were carried out using normal-hearing listeners, who were presented with speech processed by the proposed algorithm and speech processed by a conventional GSC algorithm. Results indicated large gains in speech intelligibly and speech quality in both single and multiple-noise source scenarios relative to the baseline (front microphone) condition in all target-noise configurations. The algorithm was also found to yield substantially higher intelligibility and quality than that obtained by the beamformer. The simplicity of the implementation and intelligibility benefits make this method a potential candidate for future use in commercial hearing aid and cochlear implant devices. [0070] The present application is intended to cover adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not restrictive. The scope of the present subject matter should be determined with reference to the appended claims, along with the full scope of legal equivalents to which such claims are entitled.

A novel dual-microphone speech enhancement technique is proposed that utilizes the coherence function between input signals as a criterion for noise reduction. The technique is based on certain assumptions regarding the spatial properties of the target and noise signals and can be applied to arrays with closely spaced microphones, where noise captured by sensors is highly correlated (e.g., inside a mildly reverberant environment). The proposed algorithm is simple to implement and requires no estimation of noise statistics. In addition, it offers the advantage of coping with situations in which multiple interfering sources located at different azimuths might be present.

This is a continuation of application Ser. No. 059,735, filed June 8, 1987 now abandoned. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a slit lamp microscope and more particularly to a slit lamp microscope adapted for use in examination and diagnosis with respect to such tissues of the eye as the cornea and crystalline lens. 2. Description of the Prior Art In the conventional slit lamp microscope, the white light from a light source such as a halogen lamp is passed through a slit formed between the opposing edges of two shield plates, the beam obtained in this way is directed onto an eye to be examined and the state of the cornea, crystal line lens etc. of the eye are observed using the light scattered by these eye tissues. Because of its use of a halogen lamp or the like, however, the conventional slit lamp microscope has low illuminating light intensity and, as a result, it has not been possible with the microscope to observe slight cloudiness, turbidity and the like. Moreover, since the width of the slit is varied by adjusting the gap between the two shield plates, the quantity of light illuminating the eye under examination grows smaller as the width of the gap is narrowed. It has thus been impossible to reduce the size of the observation region beyond a certain limit. SUMMARY OF THE INVENTION One object of the invention is to provide a slit lamp microscope in which the intensity of the illuminating light is high and the ratio between the length and width of the illuminating light cross-section can be accurately adjusted over a wide range. Another object of the invention is to provide a slit lamp microscope in which the quantity of illuminating light is not changed when the width of the light from the slit is narrowed. The slit lamp microscope according to the present invention is used to observe the cornea, crystalline lens and other tissues of the eye. It comprises a laser source for producing a laser beam; a projector for projecting the laser beam onto the eye to be examined; scanning means for scanning the laser beam vertically and horizontally within a selected area of the eye to be examined to form thereon a slit image which illuminates the selected area; optical means for receiving light scattered by the selected area of the eye to be examined and/or photographing an image of the eye; and light regulating means for regulating the intensity of the laser beam to a predetermined level depending upon the quantity of light received by the optical means. In the preferred embodiment of the invention, the scanning area defined by the scanning means is made variable to provide a slit image or pattern which is variable in size. The light regulating means includes a pair of linear polarizers through which the laser beam passes. One of the linear polarizers is caused to be rotated relative to the other to regulate the intensity of the laser beam depending upon the quantity of light received by the optical means. With the aforesaid arrangement according to the present invention, by scanning a laser beam of high light intensity in the vertical and horizontal directions, it becomes possible to freely adjust the ratio between the length and width of the illuminating light cross-section. In particular, if the horizontal scanning width is reduced to the width of a single laser beam, it become possible to observe a cross-section of the cornea, crystalline lens or the like using an extremely narrow slit beam. Moreover, the invention makes it possible to maintain the quantity of received light at a constant value regardless of changes in the dimensions of the slit beam. Further, since the intensity of the laser light is high, it becomes possible to reliably conduct examination and diagnosis even with respect to slight disorders of the cornea, crystalline lens and the like, which facilitates early detection of diseases of the eye. BRIEF DESCRIPTION OF THE DRAWINGS The objects and features of the present invention will become more apparent from a consideration of the following description taken in conjunction with the accompanying drawings in which: FIG. 1 is a schematic diagram of the slit lamp microscope according to the present invention; FIGS. 2A and 2B are explanatory views indicating the manner in which scanning of the laser beam in the vertical direction is conducted; FIGS. 3A and 3B are explanatory views indicating the manner in which scanning of the laser beam in the horizontal direction is conducted; and FIG. 4 is an explanatory view of the light quantity adjustment system. DETAILED DESCRIPTION OF THE INVENTION The invention will now be described with reference to the attached drawings. Referring to FIG. 1, for illuminating an eye 1 to be examined, the slit lamp microscope has an illuminating optical system consisting of a laser source 4, linear polarizers 6 and 7, a reflecting mirror 8, a beam expander 9, a reflecting mirror 10 for vertical scanning, a reflecting mirror 11 for horizontal scanning, a projection lens 12 and a reflecting mirror 13. The slit lamp microscope further has an optical system for visual and photographic observation of a cross-sectional image produced from the light scattered by the eye 1. More specifically, light scattered from the eye 1 and traveling along a different optical path from that of the illuminating light enters an objective lens 14, passes through a variable power optical system 15 and impinges on a swingable reflecting mirror 16. In the case of visual observation, the swingable mirror 16 reflects the light beam onto a beam splitter 17, from which a part of the beam is reflected into an eyepiece 19 for observation by the operator. The remainder of the beam is transmitted through the beam splitter 17 to a light quantity sensor 18 which detects the quantity of light and sends a corresponding signal to a light regulating controller 3 to be described later. In the case of photographic observation, the swingable mirror 16 swings upward, allowing the light beam from the variable power optical system 15 to be reflected by a reflecting mirror 20, to pass through photographic lens 21, 22 and a stop 22, and thereby to be projected onto the surface of a photographic film 23. For producing the slit beam, the slit lamp microscope is provided with a scanning means for scanning the laser beam in the horizontal and vertical directions along a locus. This means is constituted by the reflecting mirror 10 for the vertical scanning, the reflecting mirror 11 for the horizontal scanning and a scanning controller 2. The scanning controller 2 is equipped with a drive mechanism for synchronously driving the reflecting mirror 10 to oscillate about a shaft 10a (extending perpendicularly to the drawing sheet) and synchronously driving the reflecting mirror 11 to oscillate about a shaft 11a. As shown in FIGS. 2A and 2B, the amount of oscillation of the reflecting mirror 10 can be controlled to vary the scanning range V in the vertical direction, while, as shown in FIGS. 3A and 3B, the amount of oscillation of the reflecting mirror 11 can be controlled to vary the scanning range H in the horizontal direction. The reflecting mirrors 10 and 11 are independently controlled by the scanning controller 2 with respect to scanning velocity and scanning range. The maximum quantity of the laser beam light is restricted so as not to exceed the safety standards and the adjustment is carried out to attenuate the light quantity from this maximum quantity by means of the light regulating controller 3, the pair of linear polarizers 6 and 7 and the light quantity sensor 18. As shown in FIG. 4, the light quantity sensor 18 detects the light quantity and sends an electrical signal representing the detected light quantity to the light regulating controller 3. A motor 5 is driven by the light regulating controller 3 to rotate the linear polarizer 6 in such manner than when the light quantity is too large, the linear polarizer 6 is rotated with respect to the linear polarizer 7 so as to bring the angle of intersection between the polarization directions of the linear polarizers 6 and 7 (see arrows) closer to 90 degrees, in this way increasing the amount of attenuation and reducing the light quantity. On the contrary, when the quantity of light is insufficient, the linear polarizer is rotated to bring the polarization directions of the linear polarizers 6 and 7 closer to the alignment, in this way decreasing the amount of attenuation and increasing the light quantity. While the adjustment of the light quantity has been described here as being carried out automatically, it is alternatively possible to carry out the adjustment by manually rotating the linear polarizer 6. Further, the linear polarizers 6 and 7 can be replaced by a continuously variable ND filter of rotationally adjustable type. The operation of the slit lamp microscope of the aforesaid arrangement will now be explained. The laser beam produced by the laser 4 has its light quantity adjusted by the linear polarizers 6 and 7 and then is passed through the beam expander 9 to have its beam diameter enlarged. The loser bam is then scanningly deflected by the reflecting mirrors 10 and 11 so as to produce an appropriate slit beam, and the scanningly deflected beam (slit beam) then proceeds through the projection lens 12 to the reflecting mirror 13 from which it is reflected to illuminate the eye 1. Light scattered from within the eye 1 enters the optical system for visual and photographic observation. The incoming scattered light is first converged by the objective lens 14 and then enters the variable power optical system 15 where the observation magnfication is determined. Next, in the case of visual observation, the scattered light is reflected in the direction of the visual observation optical system (in the direction of beam splitter 17) by the swingable mirror 16, and in the case of photographic observation, the scattered light is passed in the direction of the photographic optical system (in the direction of reflecting mirror 20). During visual observation, the scattered light reflected by the swingable mirror 16 is divided into two beams by the beam splitter 17, one of which advances to the eyepiece 19 and the other of which advances to the light quantity sensor 18. As was mentioned earlier, the light quantity sensor 18 sends a signal representing the light quantity to the light regulating controller 3 which then adjusts the quantity of light based on the signal. Alternatively, however, it is possible for the operator examining the cornea, crystalline lens or the like through the eyepiece 19 to control the quantity of light by manually adjusting the linear polarizer 6. During photographic observation, the scattered light passed to the photographic optical system is reflected toward the photographic lenses 21 by the reflecting mirror 20, whereby the film 23 is exposed to a projected cross-sectional image of the cornea, crystalline lens or the like. In the illumination of the eye with the slit beam, the vertical scanning range V and the horizontal scanning range H can be appropriately varied as desribed earlier by the manner in which the scanning controller 2 drives the reflecting mirrors 10 and 11 to designate an area to be observed. The area of the slit can thus be varied by adjusting the scanning ranges, and if the light quantity of the slit beam should be changed, it is automatically readjusted by the light regulating controller 3 to maintain the light quantity constant. While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention should not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out the invention, but that the invention will include all embodiments falling within the scope of the appended claims.

A slit lamp microscope for use in observing the cornea, crystalline lens and other tissues of an eye includes a scanning device for scanning the laser beam vertically and horizontally within a selected area of the eye to be examined to form thereon a slit image which illuminates the selected area. A regulating device is provided for regulating the intensity of the laser beam to a predetermined level depending upon the amount of light reflected from the eye. The scanning device is controlled to change its scanning area to make the selected area variable to thereby provide a slit image which is changeable in size.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for sealing a heat transfer unit and in particular to a method for sealing a heat transfer unit, which significantly reduces the length of the dead zone and improves heat conduction efficiency. [0003] 2. Description of Prior Art [0004] With the rapid development of electronic information industry, the processing capability of the electronic device such as a CPU increasingly grows with the increasing generated heat. The heat-dissipation module combining a heat-dissipation fin and a fan has not been able to meet the requirement of heat dissipation, especially for a notebook computer. The heat pipe is a currently and commonly used device for heat transfer. The heat pipe can be considered a passive heat transfer device with high heat conductivity. Using the mechanism of two-phase heat transfer, the heat transfer capability of the heat pipe is hundreds times as large as copper having the same size. The heat pipe used as a medium of heat transfer has the advantages of fast response and small heat resistance. Therefore, the highly efficient heat-dissipation module developed from the heat pipe or its derived product is suitable to solve the heat-dissipation problems caused by high performance electronic products. [0005] As for the traditional method for sealing a heat pipe, the heat pipe is firstly vacuumed through a pipe opening and a working liquid is filled in the heat pipe. Then, the pipe opening is stretched and shrinks to form a necking end. Next, welding (e.g., argon welding) is performed at the necking end. In this way, the necking end is sealed. However, the necking section of the traditional heat pipe cannot conduct heat, which results in a dead zone of heat transfer. The dead zone will lower heat conduction efficiency of the heat pipe (that is, poor heat conduction of the heat pipe). Also, the necking section of the heat pipe is longer, which shortens the effective heat transfer length of the heat pipe such that when the heat pipe is installed in a smart mobile device such as a smart watch, a smart phone, or a wearable device, the occupied space of the heat pipe will make the assembly of the smart mobile device difficult, which is unfavorable to the shrinking of the smart mobile device. [0006] Therefore, how to overcome the above problems and disadvantages is the focus which the inventor and the related manufacturers in this industry have been devoting themselves to. SUMMARY OF THE INVENTION [0007] Thus, to effectively overcome the above problems, the primary objective of the present invention is to provide a method for sealing a heat transfer unit, which can effectively reduce the length of the dead zone and improves heat conduction efficiency [0008] Another objective of the present invention is to provide a method for sealing a heat transfer unit, which can effectively reduce the arrangement space when the sealed heat pipe is used. [0009] Yet another objective of the present invention is to provide a method for sealing a heat transfer unit, which can reduce the shrinking steps of the heat pipe. [0010] To achieve the above objectives, the present invention provides a method for sealing a heat transfer unit, which includes the steps of (a) to (c). Step (a) provides a heat transfer unit having a chamber and forming at least one opening, wherein an inner wall of the chamber forms at least one wick structure, wherein a working fluid is filled in the chamber; Step (b) welds the opening to form a welding section and close the opening; and Step (c) pinches off the welding section and cuts part of the welding section to form a cutting end and complete sealing the opening of the heat transfer unit. By means of the method of the present invention, an extremely short dead zone can be obtained and high heat conduction efficiency is enhanced, further having the effects of reducing the arrangement space and shrinking steps of the heat pipe. BRIEF DESCRIPTION OF DRAWING [0011] FIG. 1 is a flow chart of the method for sealing a heat transfer unit according to the first embodiment of the present invention; [0012] FIG. 2A is a schematic view of a method for sealing a heat transfer unit according to the first preferred embodiment of the present invention in the first state; [0013] FIG. 2B is a schematic view of a method for sealing a heat transfer unit according to the first preferred embodiment of the present invention in the second state; [0014] FIG. 2C is a schematic view of a method for sealing a heat transfer unit according to the first preferred embodiment of the present invention in the third state; [0015] FIG. 2D is a schematic view of a method for sealing a heat transfer unit according to the first preferred embodiment of the present invention in the fourth state; [0016] FIG. 3 is a view of the finished product made by the method for sealing a heat transfer unit according to the first preferred embodiment of the present invention; [0017] FIG. 4A is a schematic view of a method for sealing a heat transfer unit according to the second preferred embodiment of the present invention in the first state; [0018] FIG. 4B is a schematic view of a method for sealing a heat transfer unit according to the second preferred embodiment of the present invention in the second state; [0019] FIG. 4C is a schematic view of a method for sealing a heat transfer unit according to the second preferred embodiment of the present invention in the third state; [0020] FIG. 4D is a schematic view of a method for sealing a heat transfer unit according to the second preferred embodiment of the present invention in the fourth state; [0021] FIG. 5 is a view of the finished product made by the method for sealing a heat transfer unit according to the second preferred embodiment of the present invention; [0022] FIG. 6A is a schematic view of a method for sealing a heat transfer unit according to the third preferred embodiment of the present invention in the first state; [0023] FIG. 6B is a schematic view of a method for sealing a heat transfer unit according to the third preferred embodiment of the present invention in the second state; [0024] FIG. 6C is a schematic view of a method for sealing a heat transfer unit according to the third preferred embodiment of the present invention in the third state; [0025] FIG. 6D is a schematic view of a method for sealing a heat transfer unit according to the third preferred embodiment of the present invention in the fourth state; and [0026] FIG. 7 is a view of the finished product made by the method for sealing a heat transfer unit according to the third preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0027] The present invention is to provides a method of removing the dead zone of a flat heat pipe. [0028] Please refer to FIG. 1 , which is a flow chart of the method for sealing a heat transfer unit according to the first embodiment of the present invention. Please also refer to FIGS. 2A, 2B, 2C, 2D, and 3 . In the current embodiment, a cylindrical heat pipe is used as an example of the heat transfer unit 1 for explanation. The method for sealing a heat transfer unit includes the following steps. [0029] Step ( 100 ): providing a heat transfer unit having a chamber and forming at least one opening, wherein an inner wall of the chamber forms at least one wick structure, wherein a working fluid is filled in the chamber. [0030] The heat transfer unit 1 which is a cylindrical heat pipe is provided. The heat transfer unit 1 has a chamber 11 therein; each of two ends of the heat transfer unit 1 has an opening 12 communicating with the chamber 11 . An inner wall of the chamber 11 forms at least one wick structure 13 . In the current embodiment, sintered powder is used as an example of the wick structure 13 for explanation, but not limited to this. In practice, the wick structure 13 may be grooves, a metal net, or a fiber net. A working fluid 14 (e.g., pure water, inorganic compound, alcohols, ketones, liquid metal, coolant, or organic compound) is filled in the chamber 11 . Two dead zones 15 are individually defined between the wick structure 13 and each of the two opposite openings 12 at two ends of the heat transfer unit 1 . The wick structure 13 is not formed in the dead zones 15 , which helps the working fluid 14 be filled into the chamber 11 . Therefore, the dead zones 15 of the heat transfer unit 1 cannot be used for heat transfer. [0031] Step ( 101 ): welding the opening to form a welding section and close the opening. [0032] Two openings 12 at two ends of the heat transfer unit 1 have the dead zones 15 . In the current embodiment, the dead zones 15 are the portions which cannot carry out heat transfer on the heat transfer unit 1 and in which the wick structure 13 is not formed. Ultrasonic welding is performed on the dead zones 15 via ultrasonic welding equipment 5 . The inner wall in the portion of welding is welded and closed. Also, a certain range of the inner wall is required to be closed during the ultrasonic welding. Thus, after the ultrasonic welding is performed on two openings 12 of the heat transfer unit 1 , two welding sections 2 will be produced individually to close the individual openings 12 . Besides, the chamber 11 is vacuumed during the closing process to become a vacuumed chamber 11 . [0033] Step ( 102 ): pinching off the welding section and cutting off part of the welding section to form a cutting end and complete sealing the opening of the heat transfer unit. [0034] After the ultrasonic welding is performed, two ends of the heat transfer unit 1 individually form the welding section 2 . Besides, a certain range of the welding section 2 is required to be closed during the welding. Therefore, the pinch-off equipment 6 is used to pinch off the welding section 2 and cut off part of the welding section 2 . At the pinch-off location of the welding section 2 , the pinch-off equipment 6 closes the welding section 2 again to form a cutting end 3 such that the welding section 2 and the cutting end 3 can be closed effectively and thus the heat transfer unit 1 is sealed. [0035] Therefore, the design of the present invention can be directly applied in a common finished heat transfer unit 1 , such as the above-mentioned cylindrical heat pipe, the flat heat pipe, the heat conducting plate or vapor chamber formed by an upper plate and an lower plate stacked to each other, to reduce the length of the dead zone 15 and minimize the area disposed by the dead zone 15 . As a result, the heat conduction efficiency of the heat transfer unit 1 can be relatively improved. (That is, the heat transfer unit 1 is almost the effective area.). In addition, after the dead zone 15 is effectively reduced by means of the design of the present invention, the whole length of the heat transfer unit 1 can be effectively reduced, resulting in a heat transfer unit 1 with a short and small size. In this way, when the heat transfer unit 1 of the present invention is applied in a smart mobile device such as a smart watch, smart phone, or wearable device, it occupies little space and has a space saving effect, facilitating size reduction of smart mobile devices. [0036] Please also refer to FIGS. 1, 4A, 4B, 4C, 4D, and 5 , which are flow charts of a method for sealing a heat transfer unit according to the second preferred embodiment of the present invention. The current embodiment uses a flat heat pipe for explanation, instead of a cylindrical heat pipe as the heat transfer unit 1 of the first embodiment. In the current embodiment, the method for sealing a heat transfer unit mainly includes the following steps. First, a heat transfer unit 1 is provided, which is a finished product of the flat-pressed heat pipe. The heat transfer unit 1 has a chamber 11 therein; each of two ends of the heat transfer unit 1 has an opening 12 . The inner wall of the chamber 11 forms the wick structure 13 ; the working fluid 14 is filled in the chamber 11 . Two dead zones 15 are individually defined between the wick structure 13 of an inner wall of the heat transfer unit 1 and each of the two opposite openings 12 at two ends of the heat transfer unit 1 . Then, the two ends of the heat transfer unit 1 form the welding sections 2 after the ultrasonic welding is performed. Next, the welding sections 2 are pinched off using the pinch-off equipment 6 and part of the welding sections 2 are cut off. At the pinch-off location of the welding section 2 , the pinch-off equipment 6 closes the welding section 2 again to form a cutting end 3 such that the welding section 2 and the cutting end 3 can be closed effectively and thus the heat transfer unit 1 is sealed. In the way, after the dead zone 15 is effectively reduced by means of the design of the present invention, the whole length of the heat transfer unit 1 can be effectively reduced, resulting in a heat transfer unit 1 with a short and small size. Therefore, when the heat transfer unit 1 of the present invention is applied in a smart mobile device such as a smart watch, smart phone, or wearable device, it occupies little space and has a space saving effect, facilitating size reduction of smart mobile devices. [0037] Please refer to FIGS. 1, 6A, 6B, 6C, 6D, and 7 , which are flow charts of a method for sealing a heat transfer unit according to the third preferred embodiment of the present invention. The current embodiment uses a flat vapor chamber formed by an upper plate and a lower plate stacked to each other as an example of the heat transfer unit 1 for explanation, instead of the heat transfer unit 1 of the first embodiment. In the current embodiment, the method for sealing a heat transfer unit mainly includes the following steps. First, a heat transfer unit 1 is provided, which is a flat vapor chamber. The heat transfer unit 1 has a chamber 11 therein and a filling section 4 at one end thereof. An opening 12 is formed in the filling section 4 . The inner wall of the chamber 11 is provided with the wick structure 13 ; the working fluid 14 is filled in the chamber 11 . The wick structure 13 is not disposed in the filling section 4 and thus the filling section 4 is a dead zone 15 in the current embodiment. Next, the filling section 4 of the heat transfer unit 1 is welded by the ultrasonic welding to form a welding section 2 . The welding sections 2 are pinched off using the pinch-off equipment 6 and part of the welding sections 2 are cut off. At the pinch-off location of the welding section 2 , the pinch-off equipment 6 closes the welding section 2 again to form a cutting end 3 such that the welding section 2 and the cutting end 3 can be closed effectively and thus the heat transfer unit 1 is sealed. In the way, after the dead zone 15 is effectively reduced by means of the design of the present invention, the whole length of the heat transfer unit 1 can be effectively reduced, resulting in a heat transfer unit 1 with a short and small size. Thus, when the heat transfer unit 1 of the present invention is applied in a smart mobile device such as a smart watch, smart phone, wearable device, or tablet computer, it occupies little space and has a space saving effect, facilitating size reduction of smart mobile devices. [0038] In summary, compared with the traditional method, the present invention has the following advantages. [0039] 1. The length of the dead zone can be reduced. [0040] 2. The heat conduction efficiency of the heat transfer unit can be improved. [0041] 3. The space is saved. [0042] The above-mentioned embodiments are only the preferred ones of the present invention. All variations regarding the above method, shape, structure, and device according to the claimed scope of the present invention should be embraced by the scope of the appended claims of the present invention

The present invention relates to a method for sealing a heat transfer unit, which includes the steps of providing a heat transfer unit having at least one opening, welding the opening to form a welding section and close the opening, and pinching off the welding section and cutting part of the welding section to form a cutting end and complete sealing the opening of the heat transfer unit. By means of the method of the present invention, an extremely short dead zone can be obtained and high heat conduction efficiency is enhanced, further having the effects of reducing the arrangement space and shrinking steps of the heat pipe.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application claims priority from U.S. Provisional Application for Patent No. 60/694,718 filed 28 Jun. 2005 entitled Universal Application Interface and Settlement Account Gateway. Reference also is made to an earlier filed, pending application U.S. patent application Ser. No. 09/932,808 filed 17 Aug. 2001 entitled System and Method for an Automated Benefit Recognition, Acquisition, Value Exchange, and Transaction Settlement System Using Multivariable Linear and Nonlinear Modeling. The entirety of these patent applications is incorporated by reference herein. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable. REFERENCE TO A MICROFICHE APPENDIX [0003] Not Applicable. BACKGROUND OF THE INVENTION [0004] 1. Field of the Invention [0005] The present invention describes a system and method related to membership account management structures as used by issuers and applicants. Taken together, interoperable account junctions present a digest of how two or more participants involved in establishing membership accounts can normalize the information used in diverse subscription and maintenance functions. Interoperable account junctions and related data structures will: read and understand information requirements automatically; compare issuer data compliance needs to an applicant's own set of data precondition priorities; and, either provide appropriate data exchanges between parties in order to facilitate the operation of a membership account or inform the parties when precondition priorities do not match membership compliance standards. [0006] The invention is useful in various applications including, for example, consumer reward accounts, financial accounts, and virtual attribute accounts. The invention also illustrates omnicompetent value structures within and between one or more membership accounts using currency denominations of, for example, money, airline miles, reward points, security credentials, real and virtual characteristics, and any combination thereof. The invention is designed for use by individuals, entities, and automated agents such as, for example, consumers, merchants, computerized processors, and any combination of parties conducting membership and value transactions employing network technologies such as electronic, radio frequency, optical, Internet, or any manual transfer methodologies. [0007] 2. Description of the Prior Art [0008] If a consumer wanted to subscribe to twenty different merchant loyalty programs (e.g., CVS Corporation's ExtraCare, Southwest Airlines' Rapid Rewards, Morgan Stanley Company's Discover Cashback Bonus/all trademarks and company names are used for referential purposes and are the property of their respective owners), they would need to: access twenty different locations; complete twenty different membership applications; establish and maintain twenty different accounts at each merchant's data processing location; be mindful of twenty different value trusts of various currency denominations (e.g., ExtraBucks, airline miles, money); and, be subject to twenty different avenues of full or partial identity theft. The diverse merchant application standards, irregular information formats, and distributed data storage of membership accounts along with any complementary value trusts embody not only inefficient methods but also incompetent processing structures. [0009] Membership accounts are generally offered using manual and automated means, with automated event processes possibly involving digitized personal profiles, machine-readable privacy policies, and automated data exchanges. While some membership application methods exist that assist with pre-populating electronic forms with personal information, such applications are constrained, for example, in their ability to accommodate priority rankings, assimilate non-standard data tags, and dynamically integrate new data options. In addition, current membership subscription techniques endorse the creation of an applicant's information record within every issuer's membership data store. Once created, membership accounts may incorporate a value trust designed to account for currency denominations including, for example, money or reward points. Similar to the membership account, a value trust currently must exist within every issuer's membership data store. If an applicant has more than one membership account, the current practice of one-member-multiple-accounts is burdensome since there is a lack of centralized account management as well as an inability to consolidate value trust currencies. While account aggregation services exist (e.g., Yodlee, Inc.) they are limited to accessing existing membership data within every issuer's membership data store according to the individual methodologies of each location. [0010] Marketplace participants (e.g., consumers, merchants) are presently limited in their means to conveniently initiate and manage multiple membership accounts, for example, shopper loyalty program accounts. This is due in part to a difficult discovery and subscription process, as well as a non-existent or constricted ability for a ratified member to centrally manage their merchant-based value trusts. At the present time, there are five general stages involved with membership accounts: 1) issuer definition of program requirements and features; 2) publication of the program by the issuer and discovery by an interested party; 3) the provision of information by an applicant sufficient to satisfy a request for information by the issuer; 4) the evaluation of an applicant's information with reference to the issuer's compliance requirements to produce a decision; and, 5) announcement of a disposition to the concerned parties. [0000] Membership Program Design [0011] Currently, an issuer interested in offering a membership account must first define the scope of information that will be requested from an applicant and the features that will be offered to a subscriber. Application information may consist of, for example, a first name, last name, address, gender, date of birth, and e-mail address. If a printed form is being designed, the title of a requested information element (e.g., First Name) may be displayed in a box which provides space for the applicant's written data entry. If an electronic form is designed, programming code will display a data entry title and provide an entry field on a display with further programming code associating an applicant's data entry with the appropriate membership database attribute field. The related programming code would need to adopt and adhere to established standards and data tagging if the application form expected to properly incorporate data that may be available from a digitized personal information profile (e.g., Microsoft's Vcard script: navigator. userProfile. addReadRequest(“Vcard. FirstName”);). All such programming code is readily known by one skilled in the practice of computer programming. [0000] Personal Information Profiles [0012] There are existing applications that provide a person with the ability to create a digitized profile containing personal information (e.g., Microsoft Corporation's Profile Assistant included with Microsoft Internet Explorer) and share such information when a Web site requests personal data from a visitor for application forms or other transactions. [0013] For example, a data owner can use Profile Assistant to specify and record personal registration and demographic information in a profile. Internet Explorer automatically sends this information to Web sites that require it. This saves the data owner from having to type the same information every time they visit a new Web site. This information cannot be viewed on the data owner's computer or shared with others without the data owner's permission. [0014] To share registration and demographic information with Web sites that use Profile Assistant, the data owner must visit the Web site and navigate to the forms page that collects personal registration and demographic information. If the data owner is prompted, they need to allow a data transmission to enable the Web site to collect the data owner's information. [0015] Profile Assistant information is stored securely in protected storage on the data owner's computer. Web servers can request this information, but it is shared only if the data owner gives their consent in a Profile Assistant Confirmation dialog box. There is no incentive mechanism involved to inspire the data owner to release this information. This dialog box is required and it is not possible for a Web site to access this information without the data owner's permission. Once permission is given, the information is transmitted to the Web site where a copy of the personal registration and demographic information is stored on a remote computer server. [0016] Such data profile applications provide only static classifications of an applicant's personal data, they are void of features prioritizing an issuer's data compliance requirements and an applicant's precondition priorities, they do not provide incentive mechanisms or graduated promotional levels of information requests and submissions, they do not record a history of who requested the data along with the information provided and withheld, and they do not communicate profile updates (e.g., change of residential address) which may occur from time-to-time to remote computer servers that have prior copies of registration and demographic information to name some of the limitations of the prior art. [0000] Automated Privacy Policies [0017] Profile Assistant information is considered private within the constraints of the privacy guidelines defined by the Platform for Privacy Preferences Project (P3P) architecture. P3P is a World Wide Web Consortium (W3C) project. [0018] Many company's websites consist of several different sections, each of which may collect information differently, or not at all. Each different section will likely have a privacy policy that is slightly different from the policies of other parts of a Web site. When creating a P3P policy, a designer can choose to have one general P3P policy that attempts to describe all of the various data collecting components of the site. [0019] A site's P3P policies present a snapshot summary of how the site collects, handles, and uses personal information about its visitors. P3P-enabled Web browsers and other P3P applications will read and understand this snapshot information automatically, compare it to the Web user's own set of privacy preferences, and inform the user when these preferences do not match the practices of the Web site he or she is visiting. [0020] The sole intent of P3P applications is strictly the notification of privacy policies and the acknowledgement by users of how their data may be collected and employed. The current operations either allow a user to opt-in or opt-out but do not provide options to employ opt-in incentives according to a graduated priority data schema. In terms of registration and demographic information data elements, the user is either all-in or all-out with no middle ground which points to another deficiency with the prior art. Users should be allowed to surrender personal information in exchange for premiums which may subordinate the original data release decision which was based solely on privacy concerns. [0000] Membership Application Process [0021] In one possible situation, a consumer conducting business with a merchant may discover that the merchant offers a discount or incentive for a purchase if the consumer belongs to the merchant's loyalty program. Typically, a consumer may enroll in a merchant's loyalty program either by manually completing a physical form or by completing an electronic version of the membership application form, for example, by using an Internet Web site form. [0022] At the beginning of the membership application process, the merchant requests compulsory information and possibly optional information from the applicant. This request for information may be accompanied by human- and machine-readable privacy policy formats which explain how the applicant's information may be used by the merchant. During a manual application event, the applicant may review the privacy policy communications and mentally determine if they are within acceptable limits. During a computerized application event, the privacy policy communications automate privacy decision-making based on the stipulated policy practices so that users need not read the privacy policies for every membership application they encounter. While assisting in the determination of privacy boundaries and acceptable data use, such privacy policy communications provide no connection between the merchant's data compliance needs and possible incentive structures and an applicant's data precondition priorities and valuation of their personal data. [0023] After entering personal and demographic information to complete the application form, the consumer would submit the form by any appropriate means (e.g., mailing a paper form to the merchant or a processing agent, clicking an on-screen button for an electronic version) thus causing it to be submitted by appropriate methods for a membership compliance evaluation. On receipt of the application data, the merchant or their agent will determine if the consumer has provided sufficient information to qualify for the ratification of a membership account in the merchant's loyalty program. This membership evaluation is separate from issues related to privacy policies since privacy policies affect data that may be submitted, while evaluations deal with data that has been submitted. After determining the sufficiency, or lack thereof, the consumer is notified of their application's disposition with possibilities including: 1) the creation and availability of a unique or generic object substantiating the ratification of a membership account (e.g., an individual database record, a group access code) which may confer, for example, an account identification moniker and the issuance of a physical device such as a membership card, token, or frequency; 2) a reply appealing for the completion of information that was requested by the merchant for proper membership evaluation but not supplied by the consumer; or, 3) a reply indicating the denial of the application based on non-compliance with membership requirements. [0024] In the first situation stated above regarding the issuance of an account, the consumer is recognized by the merchant as a loyalty program member upon presentation of suitable identifying credentials and may receive special features, rewards, discounts, and sundry opportunities as offered by the merchant to authenticated program members. Such features, rewards, discounts, and sundry opportunities shall be referred to as premiums as an aggregating term for convenience, but such convenient term is not intended to limit the universe of possible objects and denominations that may be employed in a transaction between two or more parties. [0025] In the second situation stated above regarding an incomplete application, the consumer is allowed to either provide additional information or discard the application by means of their action or inaction. The merchant merely requests that inappropriate or missing application entries be provided without any incentive action on the part of the merchant to obtain withheld or incomplete information. The submission of additional information will likely result in an outcome depicted in either the first or third situations as listed above, but also may result in the consumer being directed to a recurrence of the second situation, or perhaps an alternative application processing avenue. [0026] In the third situation stated above regarding the denial of an application, the consumer is notified of the rejection decision and the merchant may retain the consumer's registration and demographic information. Presently, there is no method available for the merchant to automatically monitor changes in a consumer's demographic information concerning the data elements which caused the applicant's denial in order to incorporate the most current registration and demographic information adjustments and re-evaluate a previously filed application in order to potentially generate a membership account. For example, a person who previously filed an application with a professional association and was denied a membership account based on an inadequate certification will not be automatically reconsidered if they eventually achieve an appropriate certification. While there are methods currently in operation that allow companies to monitor consumer credit scores (e.g., Experian, TransUnion, Equifax), such monitoring activities merely allow for new membership invitations to be sent to consumers if they are deemed likely prospects. Current membership processes are not capable of engaging in a holistic review of all registration and demographic information and being able to undertake the amendment of previously supplied and denied consumer application data which may exist in a company's application files. [0000] Prior Art Examples and Limitations [0027] Various proposals have been made to enhance membership application systems to provide benefits to parties such as consumers, merchants, and automated agents. However, no proposals to date have enabled membership account issuers and applicants to interact by way of an interoperable account junction to negotiate dynamic information exchanges. [0028] Referring now to FIG. 2 and FIG. 3 , therein depicted are representations of two conventional screen displays showing an electronic application form for a consumer loyalty program (e.g., XxtraKare) and a credit card bonus program (e.g., AExpress). It can thus be seen how merchants create different electronic screen displays to suit their particular preferences and information requirements. In addition to different screen displays, the issuers host their electronic applications at different Web site locations (e.g., www.cvs.com, www.americanexpress.com) which are connected to their individual membership databases. [0029] Upon ratification of a membership account, the applicant will have the ability to accrue premiums in an issuer provided value trust and such value trust will be managed by the issuer according to the terms of the program application. For example, a cash back premium may provide for the issuer of such loyalty program currency to accrue a percentage of funds due a member in an account and transfer such currency balance to the member upon a member request, at predetermined times, or upon attaining a certain minimum balance in the account. [0030] The prior art is deficient in that it is based on each membership account issuer setting program features and creating application information requirements instead of configuring its membership program to accommodate an applicant's data precondition priorities. To improve the prior art, the present invention builds a system that changes static membership features configured by the issuer into dynamic membership features negotiated by the applicant. [0031] The prior art is further deficient since any membership account and complementary value trust, conjoined with a ratified membership account, is subject to the access control of the issuer. The present invention provides an interoperable account junction to link issuer account program identifiers with applicant data stores to normalize data and provide members with expanded access and management operations. A further enhancement allows the member to select the depository destination of any complementary value trust account. Such value trust enhancements mitigate the sole authority of the issuer to control the value trust and places the primary authority of the value trust with the member. [0032] As membership activities involving the request and provision of registration and demographic information expand, the prior art is not aligned with providing effective solutions to assess and integrate an issuer's information compliance requirements and the applicant's precondition priorities. Eliminating data element conflicts, executing negotiated data exchanges, dynamically configuring feature sets, and implementing real-time data updates in membership ratification and management processes will provide benefits to users and society. Likewise, the growing use of membership value trusts with their varied currency denominations is providing more wealth to members, but such wealth is difficult to coordinate due to its distributed and diverse nature. Allowing members more direct control of such value trusts will increase the convenience and economic wealth of participants throughout the global economy. REFERENCE PUBLICATIONS [0000] Using the Profile Assistant, Microsoft Corporation, Referenced 21 Jun. 2006 from http://msdn. microsoft.com/library/default.asp?url=/workshop/management/profile/profile_assista nt.asp Platform for Privacy Preferences (P3P) Project, World Wide Web Consortium (W3C), Referenced 21 Jun. 2006 from http://www.w3.org/P3P/ Creating a CVS ExtraCare Account, CVS Corporation, Referenced 22 Jun. 2006 from https://www.cvs.com/CVSApp/cvs/gateway/registerextracare?LOGINMSG=XTRACAREMSG Get One from American Express, American Express Company, Referenced 22 Jun. 2006 from https://www201.americanexpress.com/cards/Applyfservlet?csi=51/23000/b/10/1736832841/173 165431719/0/n Account Aggregation and Integration, Yodlee, Inc., Referenced 22 Jun. 2006 from http://corporate.yodlee.com/technology/platform_overview.html SUMMARY OF THE INVENTION [0038] In view of the deficiencies of the prior art discussed before, the present invention is advantageous in that it provides a dynamically integrated data exchange and management system for membership accounts and related value trusts. [0039] In addition, the present invention functions with any membership publishing and provisioning system. It exposes and joins issuer and applicant information structures that enable the present invention to evaluate and determine linkages from an extensive catalog of linked data elements. The ongoing linkage of membership accounts with applicant data will provide issuers with continuously up-to-date member information (e.g., mailing address) and the ability to obtain newly created applicant data elements, and also allow members to enjoy simplified discovery and negotiation of issuer-sponsored opportunities. [0040] The present invention allows an applicant's precondition priorities to establish the features provided by a membership account instead of statically accepting an issuer's pre-defined offer of features. The present invention exceeds the limits of privacy policies by engaging in negotiated exchanges attempting to obtain value for the release of data. The invention may also contrast and compare proposed membership features and engage in competitive negotiations to stimulate alternative recommendations, cooperation, and solutions. [0041] Furthermore, the present invention responds to environmental changes with or without human intervention; and may evolve through selecting advantageous and prioritized results from fixed patterns and random mutations all of which provide benefit to users. [0042] Another advantage of the present invention is that it offers direct access to and control of account management operations. The present invention integrates with conventional payment, settlement, and incentive systems as well as any type of membership account. [0000] Operational Performance [0043] The present invention provides a system to tag, classify, input and store an issuer's membership account program structure and also tag, classify, input and store an applicant's registration and demographic information. Upon an applicant initiating a process to obtain a membership account, the invention correlates an issuer's account program structure with available information from an applicant's data store. A dynamic configuration of issuer features may ensue based on the information supplied by an applicant. Alternative and cooperative membership structures may be introduced and employed in a final or variable solution. Complementary value trusts, when offered with membership accounts, have the ability to be designated by the applicant and used in addition to, and as replacements for, standard issuer value trusts. Such value trusts may encompass variations in currency denominations as requested by an applicant. Membership accounts and value trusts will provide access and management operations based on the member having primary control and the issuer occupying a subordinated role in terms of access and management activities. [0044] The present invention creates an interoperable account junction by constructing a data dictionary and providing access to both issuers and applicants. For reference purposes, the present invention will be referred to as a Junction Account to distinguish it from an issuer's master profile record and an applicant's master profile record each containing operational information concerning the subscriber (e.g., name, address, service subscription rate). A Junction Account will contain information from a master profile record as well as additional application specific information including, for example, feature levels, data classifications, and such information and algorithms as may assist with the construction and operations of a Junction Account in the performance of this invention. There may be unique characteristics to issuer and applicant Junction Accounts. For example, an applicant's Junction Account will contain a reference to all submitted membership applications whether approved, disapproved, or abandoned. [0045] A program issuer will create and store a membership account structure like the one shown in FIG. 4 in their Junction Account. The issuer will define a unique MEMBERSHIP ACCOUNT ID to identify a membership account. The membership account will be associated with the issuer's unique ISSUER ACCOUNT ID. A data tag as defined in the invention's interoperable account junction data dictionary will be selected by the issuer in accordance with their membership requirements. The issuer will designate an ENTRY STANDARD indicating if, for example, the information being requested is Not Applicable, Required, or Optional. In conjunction with the ENTRY STANDARD, an issuer may use the FEATURES FIRST TIER to designate the membership features that will be provided by an applicant's provision of the data requested. For example, a tier designation of “A” may provide for a basic feature set to be incorporated in the membership account (e.g., a one percent cash back reward). The issuer may also select to offer extended features to induce the provision of the requested data by designating a FEATURES SECOND TIER classification of “B” (e.g., a two percent cash back reward). An unlimited number of feature tiers may be used by the issuer to accommodate their needs. The feature tiers may be presented on the original display of an application form, or they may be displayed on successive displays of the application form after the issuer reviews the data supplied by an applicant. [0046] Applicants create and store a personal profile account structure like the one shown in FIG. 5 in their Junction Account. A program applicant will populate their Junction Account with registration, demographic, and precondition priority information. A unique APPLICANT ACCOUNT ID is assigned to each applicant's Junction Account. An INFORMATION DATA TAG defines the data dictionary moniker and stores the applicant's information (e.g., FNAME is the first name data element and may contain the name Gregory). Ongoing access to the contents of the INFORMATION DATA TAG are influenced by setting an update option in PERMIT UPDATES (e.g., automatically communicate updated information to remote data locations, manually authorize data updates to any data location). If a new INFORMATION DATA TAG is added to the data dictionary in the future, an issuer may request it and the update status may provide it according to provision levels should an applicant enter such information in their Junction Account. When an issuer's membership application requests the contents of a specific INFORMATION DATA TAG (e.g., FNAME), the PROVISION FIRST LEVEL setting will guide the release of applicant information. A PROVISION FIRST LEVEL setting of, for example, “Supply” will provide the applicant's data for the particular data tag on the first encounter with an application form. The PROVISION FIRST LEVEL may also include, for example, settings of “Restricted” (data dependent on conditional factors), “Withhold” (data never released), and “Negotiate” (query issuer's FEATURES FIRST TIER setting, or any additional tier settings, to determine if there are incentives for providing this data, otherwise restrict applicant data unless required for membership). The PROVISION SECOND LEVEL and such further level settings operate by the same methods as the PROVISION FIRST LEVEL. The settings indicated throughout are not intended to limit the range of possible options. [0047] Once issuers and applicants have completed their respective Junction Account entries as necessary with their intended use, such membership programs and personal profiles may enter the marketplace. Upon discovering that, for example, a merchant (the issuer) provides a shopper loyalty reward program, an applicant may access the present invention by means of an Internet connection and initiate a membership application. The membership application may be hosted on the issuer's Web site and a connection made to populate the on-screen form with Junction Account data elements, or the membership application may be hosted on the present invention's Web site with similar actions as examples of operating situations. An automatic process will compare the issuer's DATA TAG IDENTIFIER requirements and ENTRY DEMAND settings to the applicant's PROVISION FIRST LEVEL and any additional provision level settings to determine what information is requested and what information will be supplied. If an applicant's PROVISION FIRST LEVEL has a setting other than “Supply,” then a series of negotiation exchanges will occur to obtain better membership features from the issuer or determine if information may be withheld without withdrawing the application. If the issuer provides additional membership features and incentives for obtaining certain information (e.g., applicant's grocery purchase history), and the applicant has set an option to negotiate for better features, then the applicant may accept an issuer-centric currency denomination or specify a preferred currency denomination for the issuer to bestow for the guarded information. Upon the determination of information to be supplied by the applicant to the issuer, such information may be guided by preferences as to where the information will be stored. The applicant may request that their data be maintained in data depository locations of the applicant's designation (DATA TRUST LOCATION). For example, a DATA TRUST LOCATION may indicate “Issuer” which would allow the data in a ratified membership account to be stored at an issuer's data store location. Another example could have a DATA TRUST LOCATION specifying a value trust account maintained at a financial institution for the maintenance of registration information and deposit of earned premiums (e.g., airline miles). Each applicant data element would have the option of designating a data store location for each data element contained in a ratified member account. The issuer would associate such data store locations with the ratified member's account and maintain information in such locations as designated. Such data store locations will provide omnicompetent value structures that accommodate any single or multiple data elements including such items as, for example, premiums with the further ability to conduct data management (e.g., add, modify, delete, transmit, receive) and processing operations (e.g., addition, multiplication, division, conversion) involving data elements. [0000] Present Invention Highlights [0048] It is an advantage of the present invention that a data dictionary provides issuers and applicants with standardized data tags specific to membership applications. Such standardized data tags provide a further advantage such that issuers and applicants may engage in the comparison and provision of similar data elements and undertake negotiations for the data. The present invention's negotiated operating structure provides another advantage such that program features may be negotiated on an individual basis. The present invention also is advantageous in that it provides applicants with the ability to select data and value trust locations allowing unprecedented control of registration and demographic information. Another advantage of the present invention is that it normalizes data between and among all parties such that there is only one central source of information thus eliminating redundant and out-of-date information being used in membership accounts. Yet another advantage of the present invention is that premiums may be directed to applicant-designated value trusts and consist of preferred currency denominations. Another advantage is that issuers will have the ability to discover information available from an applicant and provide incentives to obtain such information that may not be immediately provided in the application form. A further advantage of the present invention is that applicants will have the ability to negotiate for enhanced features before providing guarded information that may be requested by the issuer. Overall, such advantages provide a tiered-membership program structure in which issuers and applicants determine the economic value of each data element and respond as may generate the best alternatives and features for each participant. [0000] Application and Use of Benefits [0049] It is an object of the present invention to allow issuers to design and host application forms using standardized data tags on their internal servers and systems. Such internal application forms may reference Junction Account data elements and store them in a whole format (e.g., a first name locally stored consisting of “Gregory”) on an internal data store. In addition, such internal application forms may reference Junction Account data elements and store them in a referenced format (e.g., a first name remotely stored consisting of the contents of the Junction Account data element “APP-101-FNAME”) on an internal data store with access to such referenced information on an external data store. An issuer may specify that both methods be employed in the operation of their membership application form. [0050] It is a further object of the present invention to allow issuers to design and host application forms using standardized data tags on the invention's servers and systems. Such application forms may transmit applicant data (e.g., whole format, referenced format, both formats) to a data store of the issuer's selection. [0051] It is yet another object of the present invention that premiums be directed to value trusts as specified by issuers and applicants according to participant requests and requirements. EXAMPLE APPLICATION OF THE PRESENT INVENTION [0052] In order to clarify various example applications of the present invention, the following scenarios demonstrate potential operations. Application Example 1 [0053] An issuer creates a Junction Account with a related membership application to be hosted on their Web site server. The membership application requires the entry of a first name and last name and optionally requests the applicant's date of birth. The information is to be transmitted from an applicant's Junction Account to the issuer's data store by reference to the data elements. Provisions are offered to obtain an applicant's date of birth if it is not immediately provided by enhancing the features of the membership account. [0054] An applicant creates a Junction Account with their registration and demographics information. The applicant discovers and initiates an issuer's membership application and uses their Junction Account to process the application's information requests. The applicant's instructions cause the present invention to negotiate for enhanced features before supplying the guarded data element “date of birth” information. Upon achieving a negotiated settlement of information to be provided and program features to be received, the present invention's methods commits the applicant data to the issuer's data store. [0055] Since the issuer requested data elements be provided in referenced format, a unique identifier to the applicant's first name, last name, and date of birth information is sent to the issuer. The issuer's system will record the reference identifiers and be allowed access to retrieve the applicant's information in whole format. The use of the referenced format will allow the issuer always to have access to the most up-to-date applicant information. Should a new data tag be implemented at a future time, such new applicant information may be offered to the issuer dependent upon the settings which the applicant places on the data elements. [0056] If a value trust was established for premiums, any earned premiums will be deposited in the designated account as maintained by either the issuer or as maintained by the applicant or their agent. [0057] In addition to the advantages and capabilities provided to the issuer, the applicant is able to centralize the management of all membership accounts by maintaining their Junction Account. Presently, if an applicant changes their mailing address they would need to change their mailing address at every membership data store location to which they have subscribed. Since issuers may request information by reference identifier, all applicant modifications to their registration and demographic information will be automatically and immediately provided to any issuers with access to the data elements. Another enhancement for the applicant is that by designating a specified destination value trust for premium deposits and redemptions, the applicant will have the ability to access and manage the account without the need to transverse through the issuer's control or access structures. This is valuable in that any currency denomination may be contained in an omnicompetent value trust and such value trust is more secure against potential issuer bankruptcies and other operational anomalies. BRIEF DESCRIPTION OF THE DRAWINGS [0058] The present invention is described in detail below with reference to the following drawing figures of which: [0059] FIG. 1 is a block diagram of a system for creating and maintaining issuer and applicant data stores along with operations involving value stores and related functions within a transaction processing system; [0060] FIG. 2 is a conventional screen display showing an electronic application form for a consumer loyalty program; [0061] FIG. 3 is a conventional screen display showing an electronic application form for a credit card bonus program; [0062] FIG. 4 is a diagram depicting an issuer's membership account structure within a database; [0063] FIG. 5 is a diagram depicting an applicant's profile account structure within a database. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0064] The present invention is described in detail below with regard to the drawing figures briefly described above. [0065] Various implementations of the present invention consist of: a method to enable an issuer to define membership account information to be requested, features provided, access channels, and destination data stores along with all appropriate maintenance functions; a method to enable an applicant to store registration and demographic information, initiate an application for a membership account, direct such registration and demographic information as stored to an application form, negotiate for membership features, specify data element preferences, and indicate the destination data and value stores and associated locations to be used along with all appropriate maintenance functions; and, a method that permits a value trust to be controlled by an applicant and consist of various currency denominations irrespective of issuer premiums. [0066] All embodiments may utilize a means for a user to view and select data elements and associated linkages, and to transmit appropriate actions and transaction information to related parties to settle a requested transaction. In addition, all embodiments may be performed automatically without user intervention to conduct, select, and transmit appropriate actions and transaction information to related parties to settle a requested transaction. [0067] Referring now to FIG. 1 , therein depicted is a block diagram of a system for establishing and executing membership functions within a transaction processing system, such as, for example, within a shopper loyalty reward system and a Junction Account server processing system, that includes such elements as structured data, application form designs, accounts, transactions, membership form structures, and preferences and settings. System 100 is configured to allow applicants. (e.g., consumers), issuers (e.g., merchants), and value trust locations to engage in the provisioning of membership account applications and associated data request and data supply system functions. [0068] Regardless of the physical devices and mediums that are chosen for implementation, system 100 and the present invention certainly contemplate the use of any communications device and medium that will allow access to the Junction Account Server for appropriate execution to affect a particular transaction and related accounts. [0069] System 100 allows the use of data request and data supply functions that permit an issuer to create a membership account program and applicants to apply for and configure such membership program and related details. [0070] From a high level, system 100 operates to allow an applicant 110 (e.g., a consumer having created an account with the present invention) to interact with an issuer 120 (e.g., a merchant having created an account with the present invention and offering a membership program); a Junction Account server 135 ; and, value trust data stores 165 in ways not heretofore provided. Applicant 110 and issuer 120 exchange information via link 115 . Merchant 120 and Junction Account server 135 exchange information with each other via links 125 and 130 , respectively. [0071] Link 115 allows applicant 110 to exchange transaction related information, such as a data element delivered as a reference identifier, with merchant 120 . Once received in the course of a transaction (e.g., a shopper loyalty program application), merchant 120 can then re-transmit such transaction information to Junction Account server 135 for appropriate processing. After Junction Account server 135 receives such information, Junction Account server can process the transaction request from merchant 120 after reviewing registration and demographic data as maintained by applicant 110 on the Junction Account server to determine and select appropriate data elements. Junction Account server 135 continues to process the transaction request in accordance with the issuer's requirements and the applicant's precondition priorities. [0072] Links 115 , 125 , 130 , 155 , 160 , and 170 are intended to be comprised of and utilize conventional data communication processing systems and data links, as well as any state-of-the-art systems. For example, link 115 may involve the use of personal computers connected to the Internet. Additionally, other communications mediums such as dedicated telephony call centers having automated and human operations could be setup to handle the communication of transaction related information between applicant 110 , issuer 120 , Junction Account server 135 , and value trusts 165 . Personal, ultra mobile, and wireless connected computing devices are certainly envisioned for the deployment of the present invention. The use of such alternative communication and computing vehicles will be readily appreciated by those skilled in the art. [0073] In the context of the present invention, functions may be specified either by their specific and underlying computer programmed and mathematical operations (i.e., the detailed instructions executed or run to effectuate the intended task) or by labels referred to herein as “reference identifiers.” Such processing and logic will be readily apparent to those skilled in the art of computer programming. [0074] Regardless of the communications mediums and encoding methods that are chosen for implementation, system 100 and the present invention certainly contemplate the use of any communications medium and identification methodology that will allow a function or function identifier to be transmitted, received, and interpreted by Junction Account server processing systems and users that will enable recognition and execution of the appropriate functions in order to affect transactions and related accounts in a certain way. [0075] The processing that occurs to allow the negotiation of enhanced program features involves iterative and interactive type processing and will be readily appreciated by those skilled in the art of computer programming after reviewing the remainder of this section. [0076] Referring now to FIG. 2 and FIG. 3 , therein depicted are prior art representations of various issuer's application forms. It can be readily appreciated the multitude of differences between the information requested and the format of data entry. [0077] Referring now to FIG. 4 , therein depicted is a diagram of an issuer account database table 400 which is maintained at a Junction Account server as shown in FIG. 1 . In particular, issuer account database table 400 (hereinafter referred to as “table 400 ”) comprises a database management system table that is preferably used in a relational arrangement whereby table 400 is related to other tables in the particular database management system by way of common columns or table fields. In any case, table 400 is maintained in an electronic data storage device as is readily understood to those skilled in the art of computer database systems. Table 400 has a field structure including fields (from table left to right) MEMBERSHIP ACCOUNT ID, ISSUER ACCOUNT ID, DATA TAG IDENTIFIER, ENTRY DEMAND, FEATURES FIRST TIER, and FEATURES SECOND TIER. Of course, table 400 's field or column structure is simplified here for purposes of brevity; in actual implementation, many more fields may be used to record other issuer and membership program information and to record system parameters related to particular issuer records in the same or different database table. The fields form the columns of table 400 and the data records form the rows of table 400 . The layout of table 400 , including its appearance in FIG. 4 , will be readily appreciated by those skilled in the art of database management system design and implementation. It should be noted that the columns and their apparent arrangement in table 400 are merely exemplary to enable one skilled in the art to make and use the present invention; no inferences should be drawn that the table structure (logically or physically) as shown is intended to limit the structure that is ultimately implemented. [0078] The column identified with the label MEMBERSHIP ACCOUNT ID stores data representing the membership program identification codes assigned to the respective Junction Account issuer. The ISSUER ACCOUNT ID stores data representing the unique reference identifier of an issuer's master profile record. The DATA TAG IDENTIFIER stores information related to the data element tag used in an applicant's Junction Account database record for cross-reference compatibility. The ENTRY DEMAND stores information indicating if the DATA TAG IDENTIFIER specified for use is an optional, mandatory, or negotiated data entry being requested from the applicant. The FEATURES FIRST TIER stores information specifying the features the issuer is willing to provide to receive the requested DATA TAG IDENTIFIER information from an applicant. The FEATURES SECOND TIER stores information specifying the features the issuer is willing to provide to receive the requested DATA TAG IDENTIFIER information from an applicant if the applicant did not provide it on a previous tiered request. The number of tiers is unlimited and only conditioned on the issuer's desires. [0079] It should be understood that the present invention may accept information for inputting into table 400 , as well as the other tables mentioned below, by any means or methods such as, for example, information on paper forms transported by the United States Postal Service to a central data entry site, information conveyed by facsimile machines to receiving machines, electronic presentation and entry systems incorporating the Internet or any electronic communication modalities, information conveyed by voice response units or human service representatives, or data and information accessible by referencing services exposed by computer systems in a computer system-to-system arrangement using, for example, the extensible mark-up language used in computer programming. [0080] In terms of the data and information stored in table 400 , three records (i.e., rows) are shown. A first record RM 1 has been entered into the database management system and into table 400 to store data related to a membership program titled CASHBACK-2 which is associated with issuer ABC-CO-123. This record indicates that the issuer is requesting the entry of a first name (e.g., FNAME) data element from every applicant and that such entry is required for the membership application to be processed. An applicant will be provided with the membership features associated with the Feature A level (e.g., basic airline mile rewards). A second record RM 2 has been entered into the database management system and into table 400 to store data related to a membership program titled CASHBACK-2 which is associated with issuer ABC-CO-123. This record indicates that the issuer is requesting the entry of a last name (e.g., LNAME) data element from every applicant and that such entry is required for the membership application to be processed. An applicant will be provided with the membership features associated with the Feature A level (e.g., basic airline mile rewards). A third record RM 3 has been entered into the database management system and into table 400 to store data related to a membership program titled CASHBACK-2 which is associated with issuer ABC-CO-123. This record indicates that the issuer is requesting the entry of a date of birth (e.g., DOBIRTH) data element from every applicant and that such entry is optional for the membership application to be processed but includes the incentive to elevate the membership level. If an applicant provides such information on a first request, the applicant will be elevated to receiving the membership features associated with the Feature B level (e.g., double airline mile rewards). If an applicant does not provide such information on a first request, the applicant may be requested for the information a second time with a higher incentive offering to elevate the membership features to the Feature C level (e.g., triple airline mile rewards). Upon successive applicant refusals, the membership form will offer successively elevated membership features until all such elevated feature tiers as defined by the issuer are exhausted. [0081] Referring now to FIG. 5 , therein depicted is a diagram of an applicant account database table 500 which is maintained at a Junction Account server as shown in FIG. 1 . In particular, applicant account database table 500 (hereinafter referred to as “table 500 ”) comprises a database management system table that is preferably used in a relational arrangement whereby table 500 is related to other tables in the particular database management system by way of common columns or table fields. In any case, table 500 is maintained in an electronic data storage device as is readily understood to those skilled in the art of computer database systems. Table 500 has a field structure including fields (from table left to right) APPLICANT ACCOUNT ID, INFORMATION DATA TAG, PERMIT UPDATES, PROVISION FIRST LEVEL, PROVISION SECOND LEVEL, REWARD PREFERENCE, and DATA TRUST LOCATION. Of course, table 500 's field or column structure is simplified here for purposes of brevity; in actual implementation, many more fields may be used to record other applicant information and to record system parameters related to particular applicant records in the same or different database table. The fields form the columns of table 500 and the data records form the rows of table 500 . The layout of table 500 , including its appearance in FIG. 5 , will be readily appreciated by those skilled in the art of database management system design and implementation. It should be noted that the columns and their apparent arrangement in table 500 are merely exemplary to enable one skilled in the art to make and use the present invention; no inferences should be drawn that the table structure (logically or physically) as shown is intended to limit the structure that is ultimately implemented. [0082] The column identified with the label APPLICANT ACCOUNT ID stores data representing the applicant identification code assigned to the respective Junction Account applicant. The INFORMATION DATA TAG stores data representing the applicant's personal, registration, and demographic information as appropriate according to a uniform data tag moniker (e.g., FNAME for first name). The PERMIT UPDATES stores data indicating if the applicant will allow or restrict updated information to be sent to all membership accounts to which the applicant has subscribed. All membership accounts for an applicant will be recorded and linkages to appropriate issuer update processing systems are contained and stored within this present invention in order to accomplish its purposes. The PROVISION FIRST LEVEL stores data indicating if the information contents of the INFORMATION DATA TAG data element will be provided when requested during an initial application request. If a condition of “Supply” is used by the applicant, then such data element information will be supplied to the application form. If a condition of “Negotiate” is used by the applicant, then the present invention will ascertain if the issuer is willing to negotiate enhanced membership features if the information is provided. The PROVISION SECOND LEVEL stores data indicating if the information contents of the INFORMATION DATA TAG data element will be provided when requested during a second application request. If a condition of “Supply” is used by the applicant, then such data element information will be supplied to the application form. If a condition of “Request Upgrade” is used by the applicant, then the present invention will ascertain if the issuer is willing to negotiate and provide enhanced membership features if the information is provided. Upon successive issuer enhancements, the applicant will offer successively elevated membership requests until all such provision tiers as defined by the applicant are exhausted. Upon successful negotiation of enhanced membership features, and incorporation by the issuer to honor an applicant's request for preferred premiums, the applicant may provide REWARD PREFERENCE information that stores information related to the applicant's preferred premiums. The DATA TRUST LOCATION stores data indicating if the applicant requests such supplied information to be located at an issuer data store location (e.g., ISSUER) or at one or more data trust locations (e.g., cash back deposits being made to a bank account). [0083] In terms of the data and information stored in table 500 , three records (i.e., rows) are shown. A first record RA 1 has been entered into the database management system and into table 500 to store data related to an INFORMATION DATA TAG titled FNAME which is associated with applicant APP-101. This record indicates that the applicant is supplying the entry of a first name (e.g., FNAME) data element for a membership application to be processed. The applicant will allow automatic updates of this information to be sent to the issuer and the applicant will accept the standard membership features when they provide this information. A second record RA 2 has been entered into the database management system and into table 500 to store data related to an INFORMATION DATA TAG titled LNAME which is associated with applicant APP-101. This record indicates that the applicant is supplying the entry of a last name (e.g., LNAME) data element for a membership application to be processed. The applicant will allow automatic updates of this information to be sent to the issuer and the applicant will accept the standard membership features when they provide this information. A third record RA 3 has been entered into the database management system and into table 500 to store data related to an INFORMATION DATA TAG titled DOBIRTH which is associated with applicant APP-101. This record indicates that the applicant is guarding the entry of a date of birth (e.g., DOBIRTH) data element for a membership application. The applicant will allow manual updates of this information to be sent to the issuer only upon review and authorization. The applicant is willing to negotiate supplying the requested information but only if the issuer provides enhanced membership features. If the issuer accepts the negotiated counteroffer of the applicant, enhanced features and possibly preferred premiums will be issued to the applicant. If the issuer permits the designation of a value trust location, the information related to the applicant's data trust location will be supplied for use in the storage of membership information and value trust currencies. [0084] It is also contemplated that a portable computing device may be synchronized either automatically or on-demand by an applicant with a Junction Account server central system to obtain applicant information for use in a standalone membership application processing situation. For example, the applicant's information may be stored on a radio frequency identification tag capable of storing appropriate information and using it at an application kiosk to make available applicant information and precondition priorities. [0085] While various embodiments of a preferred embodiment have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. [0086] Accordingly, having fully described the present invention by way of example with reference to the attached drawing figures, it will be readily appreciated that many changes and modifications may be made in the form and steps thereof and to the invention and to any of the exemplary embodiments shown and described herein without departing from the spirit or scope of the invention which is defined in the appended claims.

The present invention describes a system and method related to membership account management structures as used by issuers and applicants. Taken together, interoperable account junctions present a digest of how two or more participants involved in establishing membership accounts can normalize the information used in diverse subscription and maintenance functions.

BACKGROUND OF THE INVENTION [0001] This invention relates generally to a stable aqueous aldehyde solution or mixtures of aldehyde solutions. [0002] Aldehydes are widely used in many industrial processes. Importantly, due to the ability of an aldehyde functional group of an aldehyde molecule to react with free amine groups of, for example, a cell membrane of a microorganism, the aldehyde demonstrates a biocidal effect by disrupting and ultimately killing the microorganism. [0003] Aldehydes are commonly used as preservatives, sanitizers, disinfectants and sporocidal agents. [0004] However aldehydes (with the exception of formaldehyde and aldehydes with carbon chain lengths of 2 to 4 carbon atoms) have a tendency, especially at low concentrations, to adopt a cyclic molecular configuration which results in the aldehyde molecule losing its biocidal efficacy. Furthermore, aldehydes (including formaldehyde and aldehydes with carbon chain lengths of 2 to 4 carbon atoms) when in a monomeric form, which is prevalent at low concentrations, have a tendency to diffuse into the atmosphere causing a health hazard as potent dermal and respiratory irritants. [0005] Aldehydes at relatively higher concentrations, left over a period of time, will polymerize with other aldehyde molecules, a process which accelerates at temperatures greater than 50° C. (and at less than 4° C. for aldehydes that have chain lengths of less than 5 carbon atoms). Once again this will result in a loss of the biocidal effect. [0006] It is known in the art to take a product containing an aldehyde solution and, before use, to dilute it. In doing so the tendency of the aldehyde molecule to polymerize is reduced. Raising the pH subsequently activates the aldehyde solution. The activation increases the reactivity of the aldehyde functional groups with the amine groups and the associated biocidal effect upon cell membranes. However the stability of the aldehyde solution is compromised in so doing to the extent that the solution is only stable for several days. [0007] There are a number of problems associated with the use of an aldehyde solution as a biocidal product. Not only does a user have to dilute the product prior to use but also activate it. The resultant diluted and activated product is corrosive, due to the high pH, and unstable beyond a month. [0008] The invention at least partially addresses the aforementioned problems. SUMMARY OF INVENTION [0009] The invention provides a stable aqueous aldehyde solution that includes: (a) an aldehyde comprising at least one of the following: a monoaldehyde (Diagram 1), a cyclic aldehyde (Diagram 2) and a dialdehyde (Diagram2) and a monoaldehyde or a cyclic aldehyde in a 0.001% to 25% m/v concentration: [0000] R—CHO  Diagram 1 [0000] OHC—R 1 —CHO  Diagram 2 [0000] R 3 —CHO  Diagram 3 and wherein: R=hydrogen, a straight hydrocarbon chain between 1 and 12 carbon atoms in length, or a branded hydrocarbon chain between 2 and 12 carbon atoms in length; —R 1 =a hydrocarbon chain between 2 and 12 carbon atoms in length; and —R 3 =a cyclic hydrocarbon having 5 or 6 carbon atoms. (b) a surfactant or detergent chosen from any one of the following: an alcohol ethoxylate surfactant, a nonylphenol surfactant, sulphonic acid, sodium lauryl ethyl sulphate, sodium lauryl sulphate, a twin chain quaternary ammonium compound and cocopropyldiamide (CPAD); (c) a sufficient amount of a pH modifier to bring the pH of the solution to within a 6.0 to 8.5 range; and (d) a buffer comprising at least one of the following: calcium acetate, magnesium acetate, sodium acetate, sodium acetate tri-hydrate, potassium acetate, lithium acetate, propylene glycol, hexalene glycol, sodium phosphate, sodium tri-phosphate, potassium phosphate, lithium phosphate, zinc perchlorate, zinc sulphate, cupric chlorate and cupric sulphate. [0018] “Stable”, in the context of the invention, refers to an aqueous aldehyde solution capable of being stored for a period of at least six months without the aldehyde molecules polymerizing or the pH dropping below 5. [0019] The stable aqueous aldehyde solution may include any of the following aldehydes: formaldehyde, acetaldehyde, proprionaldehyde, butraldehyde, pentanaldehyde, hexanaldehyde, heptanaldehyde, octanaldehyde, nonanaldehyde, glutaraldehyde, succinaldehyde, Glyoxal™, 2-ethyl hexanal, iso-valeraldehyde, chloraldehyde hydrate, furfuraldehyde, paraformaldehyde. [0020] Preferably, the stable aqueous aldehyde solution includes any of the following aldehyde mixtures: glutaraldehyde and Glyoxal™ (ethane dialdehyde); Glyoxal™ chloraldehyde trihydrate; acetaldehyde and Glyoxal™; paraformaldehyde and glutaraldehyde, glutaraldehyde and succinaldehyde and Glyoxal™ and succinaldehyde. [0021] The stable aqueous aldehyde solution preferably includes the surfactant or detergent in a 0.1% to 25% m/v concentration. [0022] The surfactant is preferably a non-ionic surfactant such as an alcohol ethoxylate surfactant. [0023] The alcohol ethoxylate surfactant may include 3 to 9 ethoxylate groups depending on the composition of the stable aqueous aldehyde solution and the foaming properties required for a specific application of the stable aqueous aldehyde solution. [0024] The buffer is preferably a mixture of sodium acetate trihydrate and potassium acetate. [0025] To maintain the pH of the stable aqueous aldehyde solution at least at 5 or above for at least 6 months, the buffer is preferably included in the solution in a concentration of at least 0.05% m/v. [0026] The pH modifier may be any one or more of the following compounds: potassium hydroxide, sodium hydroxide, sodium phosphate and sodium bicarbonate. [0027] The pH modifier is preferably potassium hydroxide in a one molar solution. [0028] The pH of the stable aqueous aldehyde solution may be maintained, at the time of manufacture, within a 7.0 to 8.5 range. [0029] A twin chain quaternary ammonium compound with sterically hindered ammonium groups may be added to the stable aqueous aldehyde solution for its fungicidal and foaming properties. [0030] To enhance the biocidal efficacy of the stable aqueous aldehyde solution one or more of the following trace elements may be added to the solution: calcium, magnesium, zinc, copper, titanium, iron, silver, sodium and gold. [0031] Sodium nitrite may be added to the stable aqueous aldehyde solution in a concentration exceeding 0.005% m/v for its anti-corrosive properties. [0032] Copper may be added to the stable aqueous aldehyde solution e.g. as cupric chlorate or cupric sulphate. [0033] Zinc may be added to the stable aqueous aldehyde solution e.g. as zinc perchlorate, zinc chloride or zinc sulphate. [0034] The stable aqueous aldehyde solution may be diluted either with distilled or potable water, an alcohol or a solvent to produce a biocidal dispersant with a greater biocidal efficacy at lower temperatures than the stable aqueous aldehyde solution in an undiluted state. [0035] The invention also provides a method of manufacturing a stable aldehyde-surfactant complex solution wherein at least one aldehyde is added to a surfactant in a first aliquot of water, at a temperature of between 40° C. to 50° C., the aldehyde is allowed to interact with the surfactant or detergent, in a complexing reaction, for at least 15 minutes whilst maintaining the temperature between 40° C. to 50° C. to produce an aldehyde surfactant complex solution, and a second aliquot of water is added after at least 15 minutes to cool the aldehyde-surfactant complex solution to below 40° C. to stop the complexing reaction. [0036] The aldehyde may be a monoaldehyde (Diagram 1), dialdehyde (Diagram 2) or a cyclic aldehyde (Diagram 3) in a 0.001% to 25% m/v concentration: [0000] R—CHO  Diagram 1 [0000] OHC—R 1 —CHO  Diagram 2 [0000] R 3 —CHO  Diagram 3 and wherein: R=hydrogen or a straight hydrocarbon chain between 1 and 10 carbon atoms in length or a branded hydrocarbon chain between 2 and 12 carbon atoms in length; —R 1 =a hydrocarbon chain between 2 and 10 carbon atoms in length; and —R 3 =a cyclic hydrocarbon having 5 or 6 carbon atoms. [0041] The surfactant may be at least one of the following; an alcohol ethoxylate surfactant, a nonylphenol surfactant, sulphonic acid, sodium lauryl ethyl sulphate, sodium lauryl sulphate, a twin chain quaternary ammonium compound and cocopropyldiamide (CPAD). BRIEF DESCRIPTION OF THE DRAWINGS [0042] The invention is further described by way of example with reference to the accompanying drawings in which: [0043] FIG. 1 illustrates a commercially available mass spectroscopy scan of acetaldehyde; [0044] FIG. 2A illustrates a mass spectroscopy scan of acetaldehyde treated in accordance with the invention; [0045] FIG. 2B illustrates an expanded portion of the mass spectroscopy scan of FIG. 2A ; [0046] FIG. 3A illustrates a mass spectroscopy scan of untreated acetaldehyde and a surfactant; and [0047] FIG. 3B illustrates an expanded portion of the mass spectroscopy scan of FIG. 3A . DESCRIPTION OF PREFERRED EMBODIMENT [0048] A stable aqueous aldehyde solution, according to the invention, is manufactured, in a concentrate solution (i.e. comprising aldehyde compounds in the range 2 to 10% m/v), by first adding a non-ionic surfactant i.e. alcohol ethoxylate (with 3, 7 or 9 ethoxylate groups), to water heated to a temperature between 40° and 50° C. followed by an aldehyde or an aldehyde mixture chosen from Table 1 (hereinafter referred to as “the aldehyde”). [0000] TABLE 1 aldehyde aldehyde mixture Preferred surfactant 1. Glyoxal ™/glutaraldehyde alcohol ethoxylate 7 2. Glyoxal ™ alcohol ethoxylate 9 3. Glyoxal ™/chloraldehyde alcohol ethoxylate 9 trihydrate 4. succinaldehyde alcohol ethoxylate 7 5. Glutaraldehyde/succinaldehyde alcohol ethoxylate 7 6. Glyoxal ™/succinaldehyde alcohol ethoxylate 9 7. acetaldehyde alcohol ethoxylate 9 8. acetaldehyde/Glyoxal ™ alcohol ethoxylate 9 9. glutaraldehyde/ alcohol ethoxylate 9 paraformaldehyde [0049] The aldehyde is allowed to complex with the preferred alcohol ethoxylate (as indicated in Table 1 alongside the relevant aldehyde) for a period of between 15 and 30 minutes. This produces an aldehyde-surfactant solution, whilst maintaining the temperature of the body of water between 30° C. and 70° C. During this period of heating the aldehyde complexes with the alcohol ethoxylate substantially to completion (see FIGS. 2 and 3 ). [0050] Following this period, a further amount of water, at a temperature of less than 25° C., is added to the aldehyde-surfactant complex solution to reduce the temperature of the solution to below 30° C. thereby to stop the complexing reaction of the alcohol ethoxylate with the aldehyde. [0051] A pH modifier, such as potassium hydroxide, is then added in a sufficient quantity to adjust the pH of the succinaldehyde-surfactant complex solution to within 7.0 to 85 Potassium hydroxide is used in a one molar solution. [0052] Finally a buffer mixture comprising sodium acetate trihydrate and potassium acetate is added to the aldehyde-surfactant complex solution to produce a stable aqueous aldehyde solution in the concentrate solution. [0053] Sodium acetate trihydrate and potassium acetate each have a concentration in the buffer mixture of between 0.250 to 0.500 grams/liter. This concentrated solution is diluted when added to the aldehyde-surfactant complex solution to within the range 0.005% to 0.1% m/v. [0054] The buffer mixture maintains the pH of the concentrate during the shelf life of the stable aqueous aldehyde solution, i.e. at least 6 months from manufacture, at least above pH 5. [0055] The concentrate solution of the stable aqueous aldehyde solution includes the following contents in the following concentrations: [0000] (a) aldehyde  0.01% to 25% m/v; (b) alcohol ethoxylate   0.1% to 25% m/v; and (c) the buffer mixture 0.05% to 0.1% m/v. [0056] To enhance the biocidal efficacy of the stable aqueous aldehyde solution, one or more of the following trace elements are added, in a concentration not exceeding 5 ppm, to the solution: calcium, magnesium, zinc, copper, titanium, iron, silver and gold. [0057] To produce a biocidal product capable of application, by a variety of means, to a variety of surfaces, the concentrate solution of the stable aqueous aldehyde solution is diluted with potable water to produce a dispersant with aldehyde in a 0.001% to 8% m/v concentration. [0058] The dispersant finds application as an additive to degreasing agents, detergents, thickeners, fragrances, colorants, skin conditioners and a variety of anti-microbial products. This list is exemplary and is by no means exhaustive. [0059] On the other hand, the concentrate solution with aldehyde in a concentration in excess of 10% m/v is a favoured composition in which to transport the stable aqueous aldehyde solution. [0060] An end user, on receipt of the concentrate solution, merely has to dilute the concentrate solution by a required dilution ratio for ready incorporation with other appropriate additives, to produce products such as anti-microbial hand soap, hand sanitizers, medical equipment disinfectants, dishwashing liquids, and laundry detergents. Once again, this list is exemplary and is by no means exhaustive. [0061] The concentrate solution finds further application, incorporated with other mediums such as paints, resins etc, to provide a sustained release of the biocidal efficacy. [0062] It is believed that the dispersant and the concentrate solution, in the variety of applications exemplified above, have lower volatility, lower toxicity and corrosive properties, greater stability and biocidal efficacy at room temperatures relatively to an aldehyde (e.g. acetaldehyde and/or Glyoxal™) that has not been subjected to the method of the invention (i.e. at least not bound to a surfactant in a complex configuration), and which is used in comparative applications (see Table 2, Table 3 and Table 4). [0063] The stable aqueous aldehyde solution, like an uncomplexed aldehyde, is incompatible with certain unhindered nitrogen containing chemicals such as triethalamines and cocoamides. This incompatability needs to be kept in consideration when formulating with any aldehyde biocide. Example 1 Proof of Complexing [0064] To demonstrate complexing of the aldehyde with the surfactant a comparison is made between FIG. 1 and FIG. 2 . [0065] From FIG. 2 it is evident that there are no free acetaldehyde spectra between 0 to 100 mass to charge (m/z) where acetaldehyde indicative peaks would appear (see FIG. 1 ) if “free” aldehyde was present. [0066] FIG. 3 exhibits the separate mass spectra of the surfactant and the aldehyde used in FIG. 2 , but uncomplexed with each other. By comparing FIG. 2 with FIG. 3 it can be seen that the spectra of FIG. 2 have shifted to the right with respect to the spectra of FIG. 3 , indicating the complexing of the aldehyde with the surfactant. [0067] The sample of FIG. 2 was produced by adding 50 ml acetaldehyde (10% m/v) to 450 ml of a “premix” solution (2.51 bacterial filtered water, 0.9% m/v alcohol ethoxylate 7, 13.7 g potassium acetate, 13.7 g sodium acetate trihydrate) and heated to 30° C. for 15 minutes. [0068] The sample of FIG. 3 was a sample of acetaldehyde (99% m/v), mixed with an alcohol ethoxylate 7 surfactant without being subjected to the method of the invention. [0069] The method, materials and equipment used in this example are as follows: Agilent 1299LC; Agilent 6210 Agilent 6210 time-of-flight (TOF) mass spectroscopy; LC: mobile phase: 50:50 H20:MeCN+0.1% formic acid; flow: 0.2 ml/min; injection volume: 10 micro-liter; samples were directly infused into the TOF; TOE: positive ionization; gas Temp 300° C.; drying gas 8 L/min; nebulizer 35 psig; Vcap 3500V; fragmenter 140V; skimmer 60V; ref masses: 118.086255 and 922.009798. [0070] The TOF system is used in combination with a dual-nebulizer ESI source and an automated calibrant delivery system to continuously introduce low-level reference masses to achieve accurate mass assignment. For the analysis, the drying gas flow was set at 8 L/min, with gas temperature at 300° C. The nebulizer was set to 35 psig and capillary voltage was 3500V. A Fragmenter setting of 140V was used with skimmer 60V. The mass range was set to 100-3500 m/z with transients/scan equal to 10000. Internal reference mass correction was used. [0071] Stability tests, as above, were repeated on samples of the aldehydes (1 to 21) indicated in the table below. The results showed the same complexing phenomena. Example 2 Biocidal Efficacy Tests [0072] Tests were conducted using a South African Bureau of Standards (SABS) method (i.e. SABS1593), a Kelsey Sykes modified suspension test. The microorganism used in the test was Bacillus subtilis var globi . The results of the tests are tabulated below: [0000] TABLE 2 Aldehyde 2 Suspension Aldehyde 1 (% m/v) Surfactant Contact time Result 1 glutaraldehyde Glyoxal ™ 8% alcohol ethoxylate 7 2 hrs PASS 1.5% 4 hrs PASS 8 hrs PASS 2 Glyoxal ™ 16% alcohol ethoxylate 9 2 hrs PASS 4 hrs PASS 8 hrs PASS 3 Glyoxal ™ 8% chloraldehyde alcohol ethoxylate 9 2 hrs PASS trihydrate 10% 4 hrs PASS 8 hrs PASS 4 succinaldehyde 3% alcohol ethoxylate 7 2 hrs FAIL 4 hrs PASS 8 hrs PASS 5 glutaraldehyde 1% succinaldehyde 2% alcohol ethoxylate 7 2 hrs PASS 4 hrs PASS 8 hrs PASS 6 Glyoxol ™ 8% Succinaldehyde 1% alcohol ethoxylate 9 2 hrs PASS 4 hrs PASS 8 hrs PASS 7 acetaldehyde 3% alcohol ethoxylate 9 2 hrs PASS 4 hrs PASS 8 hrs PASS 8 acetaldehyde 2% Glyoxal ™ 8% alcohol ethoxylate 9 2 hrs BORDER PASS 4 hrs PASS 8 hrs PASS 9 acetaldehyde 1% paraformaldehyde alcohol ethoxylate 9 2 hrs BORDER 1% PASS 4 hrs PASS 8 hrs PASS 10 Glyoxal ™ 10% alcohol ethoxylate 3 2 hrs PASS 4 hrs PASS 8 hrs PASS 11 furfuraldehyde 5% alcohol ethoxylate 3 2 hrs BORDER PASS 4 hrs PASS 8 hrs PASS 12 furfuraldehyde 5% alcohol ethoxylate 9 2 hrs PASS 4 hrs PASS 8 hrs PASS 13 glutaraldehyde 3% alcohol ethoxylate 3 2 hrs FAIL 4 hrs PASS 8 hrs PASS 14 2-ethyl alcohol ethoxylate 3 2 hrs FAIL hexanaldehyde 10% 4 hrs FAIL 8 hrs PASS 15 2-ethyl alcohol ethoxylate 9 2 hrs FAIL hexanaldehyde 10% 4 hrs PASS 8 hrs PASS 16 nonanaldehyde alcohol ethoxylate 3 2 hrs FAIL 15% 4 hrs PASS 8 hrs PASS 17 nonanaldehyde alcohol ethoxylate 9 2 hrs FAIL 15% 4 hrs PASS 8 hrs PASS 18 chloraldehyde alcohol ethoxylate 3 2 hrs FAIL hydrate 20% 4 hrs PASS 8 hrs PASS 19 chloraldehyde alcohol ethoxylate 9 2 hrs FAIL hydrate 20% 4 hrs PASS 8 hrs PASS 20 paraformaldehyde alcohol ethoxylate 9 2 hrs FAIL 3% 4 hrs PASS 8 hrs PASS 21 formaldehyde alcohol ethoxylate 9 2 hrs FAIL 10% 4 hrs PASS 8 hrs PASS [0073] The same aldehydes as used above (i.e. 1 to 21) were re-subjected to the test, with the relevant surfactant added, but without pH adjustment and without the addition of a pH modifier and a buffer. All the aldehydes failed the 8 hour contact time with the exception of glutaraldehyde (sample 13) with a “borderline” pass. [0074] As evident from the above the invention appears effective at improving the biocidal efficacy of aldehydes. Example 3 Stability Tests [0075] [0000] TABLE 3 Sample Description of sample (% number m/v) Start 1 wk 2 wk 1 mth 2 mth 3 mth 25° C. Temp 25° C. 25° C. 25° C. 25° C. 25° C. 25° C. pH pH pH pH pH pH % aldehyde m/v % al % al % al % al % al (% al) 40° C. 40° C. 40° C. (accelerated stability test) pH pH pH % al % al % al 1 Glyoxal 10% 5.38 5.37 5.36 5.37 5.33 Slightly cloudy 10.58 10.62 10.61 10.65 5.25 5.15 2 2-ethly hexanal 10% 5.76 5.73 5.75 5.76 5.70 Milky top clear 10.35 10.35 10.4 bottom mixed all 5.53 5.47 milk 10.4 3 furfuraldehyde 10% 6.91 6.85 6.89 6.93 6.80 Clear yellow top 9.85 9.81 9.75 dark brown 6.57 6.35 bottom Mixed all creamy brown 9.87 4 glutaraldehyde 10% 5.3 5.45 5.32 5.43 5.33 Clear 10.97 10.89 10.95 (Terg 3) 5.11 5.09 11.02 5 acetaldehyde 10% 6.47 6.45 6.51 6.531 6.4 Clear 10.32 10.28 10.33 10.36 6.12 6.06 6 formaldehyde 10% 7.09 7.12 7.17 7.20 6.90 Clear 9.97 9.84 9.99 9.98 6.85 6.73 7 butyraldehyde 10% 5.22 5.3 5.28 5.36 5.20 Smells slight 10.1 10.02 10.00 cloudy top 5.04 5.02 bottom clear mixed all cloudy 10.05 8 nonanal 10% 6.38 6.44 6.43 6.53 6.35 White top cloudy 10.63 10.7 10.45 bottom mix milky 6.16 5.98 10.65 9 chloral hydrate 2% 6.32 6.35 6.3 6.41 6.29 Slight cloudy 2.18 2.19 2.18 2.18 6.00 5.87 10 paraformaldehyde 10% 7.43 7.36 7.42 7.56 7.30 Cloudy ppt 10.19 10.15 10.17 10.16 7.14 6.98 11 3% Glyoxal + tergitol 6.26 6.28 6.3 6.32 6.15 (Terg) 3 Clear oily ppt on 2.97 3.01 2.99 top 6.00 5.86 2.98 12 3% Glyoxal + Terg 9 6.33 6.32 6.33 6.34 6.19 Clear 2.97 2.98 3.00 3.02 5.99 5.74 13 3% furfuraldehyde + Terg 3 7.32 7.27 7.29 7.25 7.18 Oily brown ppt 2.84 2.86 2.84 top bottom 7.01 6.91 cloudy 2.89 14 3% furfuraldehyde + Terg 9 7.59 7.55 7.56 7.51 7.41 Clear yollow 2.81 2.80 2.78 2.79 7.27 7.02 15 3% glutaraldehyde + Terg 3 6.47 6.45 6.38 6.34 6.31 Clear oily ppt on 2.98 2.97 2.86 top 6.24 6.05 3.00 16 3% 2-ethyl hexanal + Terg 3 6.20 6.15 6.10 6.08 6.11 Clear 2.86 2.76 2.89 2.99 6.01 5.91 17 3% 2-ethyl hexanal + Terg 9 5.65 5.4 5.43 5.45 5.50 Cloudy 2.97 2.90 2.95 2.99 5.69 5.56 18 3% nonanal + Terg 3 clear 6.50 6.49 6.46 6.45 6.31 Clear oily top 2.95 2.96 2.87 bottom clear mix 6.19 6.00 cloudy 2.89 19 3% nonanal + Terg 9 clear 6.41 6.4 6.38 6.42 6.32 Milk top cloudy 2.86 2.83 2.87 bottom mix milk 6.06 5.86 2.85 20 3% of 2% chloral hydrate + 6.64 6.65 6.55 6.7 6.35 Terg 3 Clear oily top 0.12 0.11 0.12 bottom clear 6.17 5.99 0.1 21 3% of 2% chloral hydrate + 6.61 6.58 6.53 6.62 6.30 Terg 9 Clear 0.12 0.10 0.11 0.13 6.17 6.00 22 3% sodium perborate tetra 11.01 10.98 10.85 10.9 10.81 hydrate + Terg 9 Clear 10.06 10.54 (gas) 23 3% paraformaldehyde + 8.04 7.89 7.78 7.65 7.85 Terg 9 Clear slight smell 2.99 2.97 2.95 3.01 7.89 7.72 24 3% acetaldehyde + Terg 9 8.09 7.97 7.86 7.78 7.90 Clear slight smell 2.99 2.98 3.00 3.01 7.82 7.73 25 3% formaldehyde + Terg 9 7.82 7.79 7.63 7.55 7.60 Clear smell 3.06 2.99 3.00 3.1 7.46 7.36 [0076] The tests conducted at 40° C. are accelerated stability tests i.e. a 2 week period at the elected temperature (40° C.) is equivalent to a 6 month “shelf-life” period at 25° C. [0077] The aldehyde samples chosen for this test are merely exemplary of the vast number of possible aldehyde and mixed aldehyde permutations of the invention. [0078] The three month results were not available at the time of filing. Example 4 Virucidal Efficacy Tests [0079] The same aldehyde samples as used in Example 3 (i.e. 1 to 25) were tested for virucidal efficacy using a standard SABS method (SANS1288) which uses a bacteriophage with virus standard to represent enveloped and non-enveloped viruses Each of the samples passed the test.

A method of manufacturing a stable aldehyde-surfactant complex solution wherein at least one aldehyde is added to a surfactant in a first aliquot of water, at a temperature of between 40° C. to 50° C., the aldehyde is allowed to interact with the surfactant or detergent, in a complexing reaction, for at least 15 minutes whilst maintaining the temperature between 40° C. to 50° C. to produce an aldehyde-surfactant complex solution, and a second aliquot of water is added after at least 15 minutes to cool the aldehyde-surfactant complex solution to below 40° C. to stop the complexing reaction.

[0001] This invention was made with Government support under Contract No. DE-AC05-96OR22464 awarded by the United States Department of Energy. The Government has certain rights in this invention. CROSS-REFERENCE TO RELATED APPLICATIONS [0002] The following relate to the present invention and are hereby incorporated by reference: U.S. Patent Application Docket No. 0316 Method for Forming Biaxially Textured Articles by Powder Metallurgy by Goyal, filed on even date herewith; U.S. Pat. No. 5,739,086 Structures Having Enhanced Biaxial Texture and Method of Fabricating Same by Goyal et al., issued Apr. 14, 1998; U.S. Pat. No. 5,741,377 Structures Having Enhanced Biaxial Texture and Method of Fabricating Same by Goyal et al., issued Apr. 21, 1998; U.S. Pat. No. 5,898,020 Structures Having biaxial Texture and Method of Fabricating Same by Goyal et al., issued Apr. 27, 1999; U.S. Pat. No. 5,958,599 Structures Having Enhanced Biaxial Texture by Goyal et al., issued Sep. 28, 1999, U.S. Pat. No. 5,964,966 Method of Forming Biaxially Textured Substrates and Devices Thereon by Goyal et al., issued Oct. 21, 1999; and U.S. Pat. No. 5,968,877 High Tc YBCO Superconductor Deposited on Biaxially Textured Ni Substrate by Budai et al., issued Oct. 19, 1999. FIELD OF THE INVENTION [0003] The present invention relates to biaxially textured metallic substrates and articles made therefrom, and more particularly to such substrates and articles made from high purity face-centered cubic (FCC) materials using powder metallurgy techniques to form long lengths of biaxially textured sheets, and more particularly to the use of said biaxially textured sheets as templates to grow epitaxial metal/alloy/ceramic layers. BACKGROUND OlF THE lNVENTION [0004] Current materials research aimed at fabricating high-temperature superconducting ceramics in conductor configurations for bulk, practical applications, is largely focused on powder-in-tube methods. Such methods have proved quite successful for the Bi—(Pb)—Sr—Ca—Cu—O (BSCCO) family of superconductors due to their unique mica-like mechanical deformation characteristics. In high magnetic fields, this family of superconductors is generally limited to applications below 30 K. In the Re—Ba—Cu—O (ReBCO, Re denotes a rare earth element), Tl—(Pb,Bi)—Sr—(Ba)—Ca—Cu—O and Hg—(Pb)—Sr—(Ba)—Ca—Cu—O families of superconductors, some of the compounds have much higher intrinsic limits and can be used at higher temperatures. [0005] It has been demonstrated that these superconductors possess high critical current densities (J c ) at high temperatures when fabricated as single crystals or in essentially single-crystal form as epitaxial films on single crystal substrates such as SrTiO 3 and LaAlO 3 . These superconductors have so far proven intractable to conventional ceramics and materials processing techniques to form long lengths of conductor with J c comparable to epitaxial films. This is primarily because of the “weak-link” effect. [0006] It has been demonstrated that in ReBCO, biaxial texture is necessary to obtain high transport critical current densities. High J c 's have been reported in polycrystalline ReBCO in thin films deposited on special substrates on which a biaxially textured non-superconducting oxide buffer layer is first deposited using ion-beam assisted deposition (IBAD) techniques. IBAD is a slow, expensive process, and difficult to scale up for production of lengths adequate for many applications. [0007] High J c 's have also been reported in polycrystalline ReBCO melt-processed bulk material which contains primarily small angle grain boundaries. Melt processing is also considered too slow for production of practical lengths. [0008] Thin-film materials having perovskite-like structures are important in superconductivity, ferroelectrics, and electro-optics. Many applications using these materials require, or would be significantly improved by, single crystal, c-axis oriented perovskite-like films grown on single-crystal or highly aligned metal or metal-coated substrates. [0009] For instance, Y—Ba 2 —Cu 3 —O (YBCO) is an important superconducting material for the development of superconducting current leads, transmission lines, motor and magnetic windings, and other electrical conductor applications. When cooled below their transition temperature, superconducting materials have no electrical resistance and carry electrical current without heating up. One technique for fabricating a superconducting wire or tape is to deposit a YBCO film on a metallic substrate. Superconducting YBCO has been deposited on polycrystalline metals in which the YBCO is c-axis oriented, but not aligned in-plane. To carry high electrical currents and remain superconducting, however, the YBCO films must be biaxially textured, preferably c-axis oriented, with essentially no large-angle grain boundaries, since such grain boundaries are detrimental to the current-carrying capability of the material. YBCO films deposited on polycrystalline metal substrates do not generally meet this criterion. [0010] The present invention provides a method for fabricating biaxially textured sheets of alloy substrates with desirable compositions. This provides for applications involving epitaxial g$ devices on such alloy substrates. The alloys can be thermal expansion and lattice parameter matched by selecting appropriate compositions. They can then be processed according to the present invention, resulting in devices with high quality films with good epitaxy and minimal microcracking. [0011] The terms “process”, “method”, and “technique” are used interchangeably herein. [0012] For further information, refer to the following publications: [0013] 1. K. Sato, et al., “High-J c Silver-Sheathed Bi-Based Superconducting Wires”, IEEE Transactions on Maanetics, 27 (1991) 1231. [0014] 2. K. Heine, et al., “High-Field Critical Current Densities in Bi 2 Sr 2 Ca 1 Cu 2 O 8+x /Ag Wires”, Applied Physics Letters, 55 (1991) 2441. [0015] 3. R. Flukiger, et al., “High Critical Current Densities in Bi(2223)/Ag tapes”, Superconductor Science & Technology 5, (1992) S61. [0016] 4. D. Dimos et al., “Orientation Dependence of Grain-Boundary Critical Currents in Y 1 Ba 2 Cu 3 O 7−* Bicrystals”, Physical Review Letters, 61 (1988) 219. [0017] 5. D. Dimos et al., “Superconducting Transport Properties of Grain Boundaries in Y 1 Ba 2 Cu 3 O 7 Bicrystals”, Physical Review B, 41 (1990) 4038. [0018] 6. Y. Iijima, et al., “Structural and Transport Properties of Biaxially Aligned YBa 2 Cu 3 O 7−x Films on Polycrystalline Ni-Based Alloy with Ion-Beam Modified Buffer Layers”, Journal of Applied Physics, 74 (1993) 1905. [0019] 7. R. P. Reade, et al. “Laser Deposition of biaxially textured Yttria-Stabilized Zirconia Buffer Layers on Polycrystalline Metallic Alloys for High Critical Current Y—Ba—Cu—O Thin Films”, Applied Physics Letters, 61 (1992) 2231. [0020] 8. D. Dijkkamp et al., “Preparation of Y—Ba—Cu Oxide Superconducting Thin Films Using Pulsed Laser Evaporation from High Tc Bulk Material,” Applied Physics Letters, 51, 619 (1987). [0021] 9. S Mahajan et al., “Effects of Target and Template Layer on the Properties of Highly Crystalline Superconducting a-Axis Films of YBa 2 Cu 3 O 7−x by DC-Sputtering,” Physica C, 213, 445 (1993). [0022] 10. A. Inam et al., “A-axis Oriented Epitaxial YBa 2 Cu 3 O 7−x -PrBa 2 Cu 3 O 7−x Heterostructures,” Applied Physics Letters, 57, 2484 (1990). [0023] 11. R. E. Russo et al., “Metal BufTer Layers and Y—Ba—Cu—O Thin Films on Pt and Stainless Steel Using Pulsed Laser Deposition,” Journal of Applied Physics, 68, 1354 (1990). [0024] 12. E. Narumi et al., “Superconducting YBa 2 Cu 3 O 6 8 Films on Metallic Substrates Using In Situ Laser Deposition,” Applied Physics Letters, 56, 2684 (1990). [0025] 13. R. P. Reade et al., “Laser Deposition of Biaxially Textured Yttria-Stabilized Zirconia Buffer Layers on Polycrystalline Metallic Alloys for High Critical Current Y—Ba—Cu—O Thin Films,” Applied Physics Letters, 61, 2231 (1992). [0026] 14. J. D. Budai et al., “In-Plane Epitaxial Alignment of YBa 2 Cu 3 O 7−x Films Grown on Silver Crystals and Buffer Layers,” Applied Physics Letters, 62, 1836 (1993). [0027] 15. T. J. Doi et al., “A New Type of Superconducting Wire; Biaxially Oriented Tl 1 (Ba 0.8 Sr 0.2 ) 2 Ca 2 Cu 3 O 9 on {100}<100> Textured Silver Tape,” Proceedings of 7 th International Symposium on Superconductivity , Fukuoka, Japan, Nov. 8-11, 1994. [0028] 16. D. Forbes, Executive Editor, “Hitachi Reports 1-meter Tl-1223 Tape Made by Spray Pyrolysis”, Superconductor Week , Vol. 9, No. 8, Mar. 6, 1995. [0029] [0029] 17 . Recrystallization, Grain Growth and Textures , Papers presented at a Seminar of the American Society for Metals, Oct. 16 and 17, 1965, American Society for Metals, Metals Park, Ohio. OBJECTS OF THE INVENTION [0030] Accordingly, it is an object of the present invention to provide new and useful biaxially textured metallic substrates and articles made therefrom. [0031] It is another object of the present invention to provide such biaxially textured metallic substrates and articles made therefrom by rolling and recrystallizing high purity face-centered cubic materials to form long lengths of biaxially textured sheets. [0032] It is yet another object of the present invention to provide for the use of said biaxially textured sheets as templates to grow epitaxial metal/alloy/ceramic layers. [0033] Further and other objects of the present invention will become apparent from the description contained herein. SUMMARY OF THE INVENTION [0034] In accordance with one aspect of the present invention, the foregoing and other objects are achieved by a biaxially textured alloy article having a magnetism less than pure Ni which comprises a rolled and annealed compacted and sintered powder-metallurgy preform article, the prefonn article having been formed from a powder mixture selected from the group of binary mixtures consisting of: between 99 at % and 80 at % Ni powder and between 1 at % and 20 at % Cr powder; between 99 at % and 80 at % Ni powder and between 1 at % and 20 at % W powder; between 99 at % and 80 at % Ni powder and between 1 at % and 20 at % V powder; between 99 at % and 80 at % Ni powder and between 1 at % and 20 at % Mo powder; between 99 at % and 60 at % Ni powder and between 1 at % and 40 at % Cu powder; between 99 at % and 80 at % Ni powder and between 1 at % and 20 at % Al powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni. [0035] In accordance with a second aspect of the present invention, the foregoing and other objects are achieved by a biaxially textured alloy article having a magnetism less than pure Ni which comprises a rolled and annealed compacted and sintered powder-metallurgy preform article, the prefonn article having been formed from a powder mixture selected from the group of ternary mixtures consisting of: Ni powder, Cu powder, and Al powder; Ni powder, Cr powder, and Al powder; Ni powder, W powder and Al powder; Ni powder, V powder, and Al powder; Ni powder, Mo powder, and Al powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni. [0036] In accordance with a third aspect of the present invention, the foregoing and other objects are achieved by a biaxially textured alloy article alloy article having a magnetism less than pure Ni which comprises a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni. [0037] In accordance with a fourth aspect of the present invention, the foregoing and other objects are achieved by a strengthened, biaxially textured alloy article having a magnetism less than pure Ni which comprises a rolled and annealed, compacted and sintered powder-metallurgy preform article, the prefonn article having been formed from a powder mixture selected from the group of mixtures consisting of: Ni, Ag, Ag—Cu, Ag—Pd, Ni—Cu, Ni—V, Ni—Mo, Ni—Al, Ni—Cr—Al, Ni—W—Al, Ni—V—Al, Ni—Mo—Al, Ni—Cu—Al; and at least one fine powder such as but not limited to A 1 2 O 3 , MgO, YSZ, CeO 2 , Y 2 O 3 ; and YSZ; the article having a grain size which is fine and homogeneous and further having a domininant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni. BRIEF DESCRIPTION OF THE DRAWINGS [0038] In the drawings: [0039] [0039]FIG. 1 shows a (111) pole figure for a Ni-9 at % W alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The pole figure indicates only four peaks consistent with only a well-developed {100}<100>, biaxial cube texture. The final annealing temperature of the sample was 1200° C. [0040] [0040]FIG. 2 shows a phi (φ) scan of the [111] reflection, with φ varying from 0° to 360°, for a Ni-9 at % W alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The presence of four peaks is with only a well-developed {100}<100>, biaxial cube texture is apparent. The final annealing temperature of the sample was 1200° C. The FWHM of the φ-scan, as determined by fitting a gaussian curve to one of the peaks is ˜ 8 . 8 °. The FWHM of the peaks in this scan is indicative of the in-plane texture of the grains in the sample. [0041] [0041]FIG. 3 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked in the rolling direction, for a Ni-9 at % W alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1200° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜6.1°. [0042] [0042]FIG. 4 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked about the rolling direction, for a Ni-9 at % W alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1200° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜8.5°. [0043] [0043]FIG. 5 shows a (111) pole figure for a Ni-9 at % W alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The pole figure indicates only four peaks consistent with only a well-developed {100}<100>, biaxial cube texture. The final annealing temperature of the sample was 1400° C. [0044] [0044]FIG. 6 shows a phi (φ) scan of the [111] reflection, with φ varying from 0° to 360°, for a Ni-9 at % W alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The presence of four peaks is with only a well-developed {100}<100>, biaxial cube texture is apparent. The final annealing temperature of the sample was 1400° C. The FWHM of the φ-scan, as determined by fitting a gaussian curve to one of the peaks is ˜5.8°. The FWHM of the peaks in this scan is indicative of the in-plane texture of the grains in the sample. [0045] [0045]FIG. 7 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked in the rolling direction, for a Ni-9 at % W alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1400° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜4.3°. [0046] [0046]FIG. 8 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked about the rolling direction, for a Ni-9 at % W alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1400° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜7.4°. [0047] [0047]FIG. 9 shows a (111) pole figure for a Ni-13 at % Cr alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The pole figure indicates only four peaks consistent with only a well-developed {100}<100>, biaxial cube texture. The final annealing temperature of the sample was 1200° C. [0048] [0048]FIG. 10 shows a phi (φ) scan of the [111] reflection, with φ varying from 0° to 360°, for a Ni-13 at % Cr alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy ,, preform. The presence of four peaks is with only a well-developed {100}<100>, biaxial cube texture is apparent. The final annealing temperature of the sample was 1200° C. The FWHM of the φ-scan, as determined by fitting a gaussian curve to one of the peaks is ˜8.7°. The FWHM of the peaks in this scan is indicative of the in-plane texture of the grains in the sample. [0049] [0049]FIG. 11 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked in the rolling direction, for a Ni-13 at % Cr alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1200° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as b detenined by fitting a gaussian curve to one of the peaks is ˜5.8°. [0050] [0050]FIG. 12 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked about the rolling direction, for a Ni-13 at % Cr alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preforn. The final annealing temperature of the sample was 1200° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜9.8°. [0051] [0051]FIG. 13 shows a (111) pole figure for a Ni-13 at % Cr alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The pole figure indicates only four peaks consistent with only a well-developed {100}<100>, biaxial cube texture. The final annealing temperature of the sample was 1400° C. [0052] [0052]FIG. 14 shows a phi (φ) scan of the [111] reflection, with φ varying from 0° to 360°, for a Ni-13 at % Cr alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The presence of four peaks is with only a well-developed {100}<100>, biaxial cube texture is apparent. The final annealing temperature of the sample was 1400° C. The FWHM of the φ-scan, as determined by fitting a gaussian curve to one ofthe peaks is ˜6.1°. The FWHM of the peaks in this scan is indicative of the in-plane texture of the grains in the sample. [0053] [0053]FIG. 15 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked in the rolling direction, for a Ni-13 at % Cr alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1400° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜4.5°. [0054] [0054]FIG. 16 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked about the rolling direction, for a Ni-13 at % Cr alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1400° C. The peak is indicative of the out-of-plane texture of the sample The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜7.3°. [0055] [0055]FIG. 17 shows a (111) pole figure for a Ni-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The Mg is predominantly expected to be present as MgO. The pole figure indicates only four peaks consistent with only a well-developed {100}<100>, biaxial cube texture. The final annealing temperature ofthe sample was 1200° C. [0056] [0056]FIG. 18 shows a phi (φ) scan of the [111] reflection, with φ varying from 0° to 360°, for a Ni-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform The presence of four peaks is with only a well-developed {100}<100>, biaxial cube texture is apparent. The final annealing temperature of the sample was 1200° C. The FWHM of the φ-scan, as determined by fitting a gaussian curve to one of the peaks is ˜7.7°. The FWHM of the peaks in this scan is indicative of the in-plane texture of the grains in the sample. [0057] [0057]FIG. 19 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked in the rolling direction, for a Ni-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1200° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜7.8°. [0058] [0058]FIG. 20 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked about the rolling direction, for a Ni-0.03 at % Mg. The final annealing temperature of the sample was 1200° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting, a gaussian curve to one of the peaks is ˜9.2°. [0059] [0059]FIG. 21 shows a (111) pole figure for a Ni-9 at % W-0.03 at % Mg alloy fabricated by rolling and annealing a comnpacted and sintered, powder metallurgy preform. The Mg is predominantly expected to be present as MgO. The pole figure indicates only four peaks consistent with only a well-developed {100}<100>, biaxial cube texture. The final annealing temperature of the sample was 1200° C. [0060] [0060]FIG. 22 shows a phi (φ) scan of the [111] reflection, with φ varying from 0° to 360°, for a Ni-9 at % W-0.03 % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy prefonn. The presence of four peaks is with only a well-developed {100}<100>, biaxial cube texture is apparent. The final annealing temperature of the sample was 1200° C. The FWHM of the φ-scan, as determined by fitting a gaussian curve to one of the peaks is ˜9.1°. The FWHM of the peaks in this scan is indicative of the in-plane texture of the grains in the sample. [0061] [0061]FIG. 23 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked in the rolling direction, for a Ni-9 at % W-0.03% Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1200° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜7.2°. [0062] [0062]FIG. 24 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked about the rolling direction, for a Ni-9 at % W-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1200° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜9.1°. [0063] [0063]FIG. 25 shows a (111) pole figure for a Ni-9 at % W-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The Mg is predominantly expected to be present as MgO. The pole figure indicates only four peaks consistent with only a well-developed {100}<100>, biaxial cube texture. The final annealing temperature of the sample was 1400° C. [0064] [0064]FIG. 26 shows a phi (φ) scan of the [111] reflection, with φ varying from 0° to 360°, for a Ni-9 at % W-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform The presence of four peaks is with only a well-developed {100}<100>, biaxial cube texture is apparent. The final annealing temperature of the sample was 1400° C. The FWHM of the φ-scan, as determined by fitting a gaussian curve to one of the peaks is ˜6.1°. The FWHM of the peaks in this scan is indicative of the in-plane texture of the grains in the sample. [0065] [0065]FIG. 27 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked in the rolling direction, for a Ni-9 at % W-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy prefonn. The final annealing temperature of the sample was 1400° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜6.7°. [0066] [0066]FIG. 28 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked about the rolling direction, for a Ni-9 at % W-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1400° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜7.5°. [0067] [0067]FIG. 29 shows a (111) pole figure for a Ni-13 at % Cr-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The Mg is predominantly expected to be present as MgO. The pole figure indicates only four peaks consistent with only a well-developed {100}<100>, biaxial cube texture. The final annealing temperature of the sample was 1200° C. [0068] [0068]FIG. 30 shows a phi (φ) scan of the [111] reflection, with φ varying from 0° to 360°, for a Ni-13 at % Cr-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The presence of four peaks with only a well-developed {100}<100>, biaxial cube texture is apparent. The final annealing temperature of the sample was 1200° C. The FWHM of the φ-scan, as determined by fitting a gaussian curve to one of the peaks is ˜8.1°. The FWHM of the peaks in this scan is indicative of the in-plane texture of the grains in the sample. [0069] [0069]FIG. 31 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked in the rolling direction, for a Ni-13 at % Cr-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1200° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜5.1°. [0070] [0070]FIG. 32 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked about the rolling direction, for a Ni-13 at % Cr-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy prefonn. The final annealing temperature of the sample was 1200° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜9.5°. [0071] [0071]FIG. 33 shows a (111) pole figure for a Ni-13 at % Cr-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preforn. The Mg is predominantly expected to be present as MgO. The pole figure indicates only four peaks consistent with only a well-developed {100}<100>, biaxial cube texture. The final annealing temperature of the sample was 1400° C. [0072] [0072]FIG. 34 shows a phi (φ) scan of the [111] reflection, with φ varying from 0° to 360°, for a Ni-13 at % Cr-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The presence of four peaks is with only a well-developed {100}<100>, biaxial cube texture is apparent. The final annealing temperature of the sample was 1400° C. The FWHM of the φ-scan, as determined by fitting a gaussian curve to one of the peaks is ˜6.5°. The FWHM of the peaks in this scan is indicative of the in-plane texture of the grains in the sample. [0073] [0073]FIG. 35 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked in the rolling direction, for a Ni-13 at % Cr-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1400° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the ω-scan, as determined by fitting a gaussian curve to one of the peaks is ˜6.9°. [0074] [0074]FIG. 36 shows a rocking curve (ω-scan) from 10° to 40° with the sample being rocked about the rolling direction, for a Ni-13 at % Cr-0.03 at % Mg alloy fabricated by rolling and annealing a compacted and sintered, powder metallurgy preform. The final annealing temperature of the sample was 1400° C. The peak is indicative of the out-of-plane texture of the sample. The FWHM of the T)-scan, as determined by fitting a gaussian curve to one of the peaks is 7.9°. DETAILED DESCRIPTION OF THE INVENTION [0075] Note: As used herein, percentages of components in compositions are atomic percent unless otherwise specified. [0076] A new method for producing highly textured alloys has been developed. It is well established in the art that high purity FCC metals can be biaxially textured under certain conditions of plastic deformation, such as rolling, and subsequent recrystallization. For example, a sharp cube texture can be attained by deforming Cu by large amounts (90%) followed by recrystallization. [0077] However, this is possible only in high purity Cu. Even small amounts of impurity elements (i.e., 0.0025% P, 0.3% Sb, 0.18% Cd, 0.47% As, 1% Sn, 0.5% Be etc.) can significantly modify the b defonnation behavior and hence the kind and amount of texture that develops on deformation and recrystallization. In this invention, a method is described to texture alloys of cubic materials, in particular FCC metal based alloys. Alloys and composite compositions resulting in desirable physical properties can be processed to forn long lengths of biaxially textured sheets. Such sheets can then be used as templates to grow epitaxial metal/alloy/ceramic layers for a variety of 2; applications. [0078] The present invention has application especially in the making of strengthened substrates with magnetism less than that of pure Ni. For a substance to have less magnetism than pure Ni implies that its Curie temperature is less than that of pure Ni. Curie temperature is known in the art as the temperature at which a metal becomes magnetic. In the following description, a material having less magnetism than that of pure Ni implies a material having a Curie temperature at least 50° C. less than that of pure Ni. [0079] Many device applications require good control of the grain boundary of the materials comprising the device. For example in high temperature superconductors grain boundary character is very important. The effects of grain boundary characteristics on current transmission across the boundary have been very clearly demonstrated for Y 123 . For clean, stochiometric boundaries, J,(gb), the grain boundary critical current, appears to be determined primarily by the grain boundary misorientation. The dependence of Jr((b) on misorientation angle has been determined by Dimos et al. [1] in Y 123 for grain boundary types which can be formed in epitaxial films on bicrystal substrates. These include [001] tilt, [100] tilt, and [100] twist boundaries [1]. In each case high angle boundaries were found to be weak-linked. The low JC observed in randomly oriented polycrystalline Y 123 can be understood on the basis that the population of low angle boundaries is small and that frequent high angle boundaries impede long-range current flow. [0080] Recently, the Dimos experiment has been extended to artificially fabricated [001] tilt bicrystals in Tl 2 Ba 2 CaCu 2 Ox [2], Tl 2 Ba 2 Ca 2 Cu 3 O[3], TlBa 2 Ca 2 Cu 2 Ox [4], and Ndi. 85 Ceo.l 5 CuO 4 [ 3 ]. In each case it was found that, as in Y 123 , JC depends strongly on grain boundary misalignment angle. Although no measurements have been made on Bi- 2223 , data on current transmission across artificially fabricated grain boundaries in Bi- 2212 indicate that most large angle [001] tilt [3] and twist [5,6] boundaries are weak links, with the exception of some coincident site lattice IA (CSL) related boundaries [5,6] It is likely that the variation in JC with grain boundary misorientation in Bi- 2212 and Bi- 2223 is similar to that observed in the well-characterized cases of Y 123 and TI-based superconductors. Hence in order to fabricate high temperature superconductors with very critical current densities, it is necessary to biaxially align essentially ,F t all the grains. This has been shown to result in significant improvement in the superconducting 2 SO, properties of YBCO films [ 7 - 10 ]. [0081] A method for producing biaxially textured substrates was taught in previous U.S. Pat. Nos. 5,739,096, 5,741,377, 5,898,020, and 5,958,599. That method relies on the ability to texture metals, in particular FCC metals such as copper, to produce a sharp cube texture followed by epitaxial growth of additional metal/ceramic layers. Epitaxial YBCO films grown on such substrates resulted in high JC. However, in order to realize any applications, one of the areas requiring significant improvement and modification is the nature of the substrate. The preferred substrate was made by starting with high purity Ni, which is first thermoinechanically biaxially textured, followed by epitaxial deposition of metal and/or ceramic layers. Because Ni is ferromagnetic, the substrate as a whole is mag,netic and this causes difficulty in practical applications involving superconductors. A second problem is the thermal expansion mismatch between the preferred substrate and the oxide layers. The thermal expansion of the substrate is dominated by that of Ni which is quite different from most desired ceramic layers for practical applications. This mismatch can result in cracking and may limit properties. A third problem is the limitation of the lattice parameter to that of Ni alone. If the lattice parameter can be modified to be closer to that of the ceramic layers, epitaxy can be obtained far more easily with reduced internal stresses. This can reduce or prevent cracking and other stress-related defects and effects (e.g. delamination) in the ceramic films Although a method to form alloys starting from the textured Ni substrate is also suggested in U.S. Pat. Nos. 5,739,086, 5,741,377, 5,898,020, and 5,958,599, its scope is limited in tenns of the kinds of alloys that can be fabricated. This is because only a limited set of elements can be homogeneously diffused into the textured Ni substrate. A method for fabricating textured alloys was proposed in another previous invention U.S. Pat. No. 5,964,966. The invention involved the use of alloys of cubic metals such as Cu, Ni, Fe, Al and Ag for making biaxially textured sheets such that the stacking fault frequency, u, of the alloy with all the alloying additions is less than 0.009. In case it is not possible to make an alloy with desired properties to have the stacking fault frequency less than 0.009 at room temperature, then deformation can be carried out at higher temperatures where the u is less than 0.009. However, that invention may be limited in the sharpness of the texture which can be attained. This is XQ because no specific control on the starting material to fabricate the biaxially textured alloys was given which results in a sharp biaxial texture. Moreover, the alloys fabricated using the methods described in the invention, result in materials which have secondary recrystallization temperatures less than 1200° C. Once the secondary recrystallization temperature is reached, the substrate essentially begins to lose all its cube texture. Low secondary recrystallization temperatures limit the sharpness of biaxial texture that can be obtained and what deposition temperatures can be used for depositing epitaxial oxide or other layers on such substrates. Furthennore, the invention does not teach how one could potentially texture and effectively use an alloy with compositions such that the stacking fault frequency of the alloy is greater than 0.009 at room temperature. Lastly, the invention does not provide a method or describe an article which effectively incorporates ceramic constituents in the alloy body to result in very significant mechanical toughening, yet maintaining the strong biaxial texture. A metallic object such as a metal tape is defined as having a cube texture when the [100} crystallographic planes of the metal are aligned parallel to the surface of the tape and the [100] crystallographic direction is aligned along the length of the tape. The cube texture is referred to as the {100}<100> texture. Here, a new method for fabricating strongly or dominantly cube textured surfaces of composites which have tailored bulk properties (i.e. thermal expansion, mechanical properties, non-magnetic nature, etc.) for the application in question, and which have a strongly textured surface that is compatible with respect to lattice parameter and chemical reactivity with the layers of the electronic device(s) in question, is described. Herein the term dominantly or strongly cube (ix tetured surface describes one that has 95% of the grains comprising the surface in the {100}<100> orientation. oriented The method for fabricating biaxially textured alloys of the herein disclosed and claimed invention utilizes powder metallurgy technology. Powder metallurgy allows fabrication of alloys zip with homogeneous compositions everywhere without the detrimental effects of compositional segregation commonly encountered when using vacuum melting or casting to make alloys. Furthermore, powder metallurgy allows easy control of the grain size of the starting alloy body. Moreover, powder metallurgy allows a fine and homogeneous grain size to be achieved. Herein, fine grain size means grain size less than 200 microns. Homogeneous grain size means variation in grain size of less than 40%. In the following we break the discussion into three parts: Procedures and examples to obtain biaxially textured alloys which have stacking fault frequencies less than 0.009 at room temperature, but have better biaxial textures and have higher secondary recrystallization temperatures. Procedures and examples to obtain biaxially textured alloys with a distribution of ceramic particles for mechanical strengthening. Procedures and examples to obtain and effectively use biaxially textured alloys which have stacking fault frequencies greater than 0.009 at room temperature. PROCEDURES AND EXAMPLES TO OBTAIN BIAXIALLY TEXTURED ALLOYS WHICH HAVE STACKING FREQUENCIES LESS THAN 0 . 009 AT ROOM TEMPERATURE, BUT HAVE BETTER BIAXIAL TEXTURES AND HAVE HIGHER SECONDARY RECRYSTALLIZATION TEMPERATURES [0082] The basic premise or idea here is that alloys are fonned by starting with high purity powders of the alloy constituents, mechanically mixing them together to fonn a homogeneous mixture, Fs> compacting and heat-treating the resulting body to form a raw article or starting preform. The }H thennomechanical treatment results in a fine and home(,eneous orain size in the initial starting preform. EXAMPLE I [0083] Begin with a mixture of 80% Ni powder (99.99% purity) and 9% W powder. Mix and compact at appropriate pressures into a rod or billet. Then heat treat at 900° C. for 2 hr. The grain size at the end of heat treatment is less than 50 sum. Deform, by rolling, to a degree greater than 90% total deformation, preferably using 10% reduction per pass and by reversing the rolling direction during each subsequent pass. Anneal at about 1200° C. for about 60 minutes to produce a sharp biaxial texture. Annealing is perfonned in flowing 4% H 2 in Ar. FIG. I shows a (I I I ) X-ray diffraction pole figure of the biaxially textured alloy substrate. As can be seen, only four peaks are evident. Each peak refers to one of four crystallographically similar orientations corresponding to {100}<100>, such that the (100) plane is parallel to the surface of the tape and <100>direction is aligned along the long axis of the tape. FIG. 2 shows a phi-scan of the [111] reflection showing the degree of in-plane texture. The FWHM of the tape is determined by fitting a gaussian curve to the data is 8.8°. FIG. 3 shows the rocking curve or the out-of-plane texture as measured by scanning the [200] reflection of the substrate. FIG. 3 is a rocking curve with the sample being rocked in the rolling direction and shows a FWHM of 6.14°. FIG. 4 is a rocking curve with the sample being rocked about the rolling direction and shows a FWHM of 8.49°. This is truly a single orientation texture with all crystallographic axis being aligned in all direction within 8-9°. Alloys made by procedures other than what is described above result in secondary recrystallization at about 1200° C. EXAMPLE II [0084] Begin with a mixture of 80% Ni powder (99.99% purity) and 9% W powder. Mix and compact at appropriate pressures into a rod or billet. Then heat treat at 900° C. for 2 hr. The grain size at the end of heat treatment is less than 50 pm. Deform, by rolling, to a degree greater than 90% total deformation, preferably using 10% reduction per pass and by reversing the rolling direction during each subsequent pass. Anneal at about 1400° C. for about 60 minutes to produce a sharp biaxial texture. Annealing is performed in flowing 4% H 2 in Ar. FIG. 5 shows a (I 1 I) X-ray diffraction pole figure of the biaxially textured alloy substrate. As can be seen, only four peaks are evident. Each peak refers to one of four crystallographically similar orientations corresponding to {100}<100>, such that the (100) plane is parallel to the surface of the tape and <100>direction is aligned along the long axis of the tape. FIG. 6 shows a phi-scan of the [ I I ] reflection showing the degree of in-plane texture. The FWHM of the tape is detenined by fitting a gaussian curve to the data is 6.30. FIG. 7 shows the rocking curve or the out-of-plane texture as measured by scanning the [200] reflection of the substrate. FIG. 7 is a rocking curve with the sample being rocked in the rolling direction and shows a FWHM of 6.7°. FIG. 8 is a rocking curve with the sample being rocked about the rolling direction and shows a FWHM of 7.50. This is truly a single orientation texture with all crystallographic axis being aligned in all direction within 6-7° Alloys made by procedures other than what is described above result in secondary recrystallization at temperatures much below 1400° C. and do not result in single orientation cube texture as shown in the pole figure of FIG. 5. EXAMPLE III Begin with a mixture of 87 at % Nickel powder (99.99% purity) and 13% Chromium powder. Mix and compact at appropriate pressures into a rod or billet. Then heat treat at 900° C. for 2 hr. The grain size at the end of heat treatment is less than 50 Fm. Deform, by rolling, to a degree ygreater than 90% total deformation, preferably using 10% reduction per pass and by reversing the rolling direction during each subsequent pass. Anneal at about 1200° C. for about 60 minutes to produce a sharp biaxial texture. Annealing is performed in flowing 4% H 2 in Ar. FIG. 9 shows a (111) X-ray diffraction pole figure of the biaxially textured alloy substrate. As can be seen, only four peaks are evident. Each peak refers to one of four crystallographically similar orientations corresponding to 100,<100>, such that the (100) plane is parallel to the surface of the tape and <100> direction is aligned along the long axis of the tape. FIG. 10 shows a phi-scan of the [I I I] reflection showing the degree of in-plane texture. The FWHM of the tape determined by fitting a gaussian curve to the data is 8.68°. FIG. 11 shows the : 5 rocking curve or the out-of-plane texture as measured by scanning the [200] reflection of the substrate. FIG. 11 is a rocking curve with the sample being rocked in the rolling direction and shows a FWHM of 5.83°. FIG. 12 is a rocking curve with the sample being rocked about the rolling direction and shows a FWHM of 9.820. This is truly a single orientation texture with all ; 9 >. crystallographic axis being aligned in all directions within 8-10°. Alloys made by procedures 2 {) other than what is described above result in secondary recrystallization at 1200° C. EXAMPLE IV Begin with a mixture of 87 at % Nickel powder (99.99% purity) and 13% Chromium powder. Mix and compact at appropriate pressures into a rod or billet. Then heat treat at 900° C. for 2 hr. The grain size at the end of heat treatment is less than 50 Em. Deform, by rolling, to a degree greater than 90% total deformation, preferably using 10% reduction per pass and by reversing the rolling direction during each subsequent pass. Anneal at about 1400° C. for about 60 minutes to produce a sharp biaxial texture. Annealing>is performed in flowing 4% H 2 in Ar. FIG. 13 shows a ( 111 ) X-ray diffraction pole figure of the biaxially textured alloy substrate. As can be seen, only four peaks are evident. Each peak refers to one of four crystallographically similar orientations corresponding to {100}<100>, such that the (100) plane is parallel to the surface of the tape and <100> direction is aligned along the long axis of the tape. FIG. 14 shows a phi-scan of the [111] reflection showing the degree of in-plane texture. The FWHM of the tape detennined by fitting a gaussian curve to the data is 6.1°. FIG. 15 shows the rocking curve or the out-of-plane texture as measured by scanning the [200] reflection of the substrate. FIG. 15 is a rocking curve with the sample being rocked in the rolling direction and shows a FWHM of 4.5°. FIG. 16 is a rocking curve with the sample being rocked about the rolling direction and shows a FWHM of 7.3°. This is truly a single orientation texture with all crystallographic axis being aligned in all directions within 6-7°. Alloys made by procedures other than the what is described above result in secondary recrystallization at temperatures much below 1400° C. and do not result in single orientation cube texture as shown in the pole figure of FIG. 13. SSimilar experiments can be performed with binary alloys of Ni—Cu, Ni—V, Ni—Mo, Ni—Al, and with ternary alloys of Ni—Cr—mAl, Ni—W—Al, Ni—V—Al, Ni—Mo—Al, Ni—Cu—Al. Similar results are also expected for 100% Ag and AO, alloys such Ag—Cu, Ag—Pd. PROCEDURES AND EXAMPLES TO OBTAIN BIAXIALLY-TEXTURED ALLOYS WITH A DISTRIBUTION OF CERAMIC PARTICLES FOR MECHANICAL STRENGTHENING [0085] Conventional wisdom and numerous experimental results indicate that hard, ceramic particles are introduced or dispersed within a metal or alloy it results in significant mechanical strengthening. This arises primarily due to enhanced defect or dislocation generation should this material be defonned. Conventional wisdom and prior experimental results also indicate because of the presence of such hard, ceramic particles, and the enhanced defect generation locally at these particles, the deformation is very inhomogeneous. Inhomogeneous deformation essentially prevents the formation of any sharp crystallographic texture. Hence, conventional wisdom and prior experimental results show that the presence of even a very small concentration of ceramic particles result in little texture fonnation even in high purity FCC metals such as Cu and Ni. Here we provide a method where ceramic particles can be introduced in a homogeneous fashion to obtain mechanical strengthening of the substrate, and still obtain a high degree of biaxial texture. The key is to have a particle size of less than lHm and uniform distribution of the ceramic particles in the final preform, prior to the final rolling to obtain biaxial texture. EXAMPLE V Begin with a mixture of 0.03 at % Mg and remaining Ni powder. Mix and compact at appropriate pressures into a rod or billet. Then heat treat at 900° C. for 2 hr. During this thennomechanical processing all the Mg is converted to MgO and it is dispersed in a fine and homogeneous manner throughout the prefonn. The grain size at the end of heat treatment is less than 50 Dm. Deform, by rolling, to a degree greater than 90% total deformation, preferably using 10% reduction per pass and by reversing the rolling direction during each subsequent pass. Anneal at about 1200° C. for about 60 minutes to produce a sharp biaxial texture. Annealing is perfonned in flowing t5 4 % H 2 in Ar. [0086] [0086]FIG. 17 shows a (111) X-ray diffraction pole figure of the biaxially textured, particulate, composite substrate. As can be seen, only four peaks are evident. Each peak refers to one of four crystallograplically sinilar- orientations corresponding to {100}<100>, such that the (100) 2 i;W). plane is parallel to the surface of the tape and <100> direction is aligned along the long axis of the tape. FIG. 18 shows a phi-scan of the [111] reflection showing the degree of in-plane texture. The FWHM of the tape determined by fitting a gaussian curve to the data is 8.68°. FIG. 19 shows the rocking curve or the out-of-plane texture as measured by scanning the [200] reflection of the substrate. FIG. 19 is a rocking curve with the sample being rocked in the rolling direction and shows a FWHM of 7.920. FIG. 20 is a rocking curve with the sample being rocked about the rolling direction and shows a FWHM of 9.20°. This is truly a single orientation texture with all crystallographic axis being aligned in all directions within 8-10°. Alloy substrates made by procedures other than what is described above undergo secondary recrystallization at such annealing temperatures and lose most of their biaxial texture. On the contrary, the substrates reported here improve their biaxial textures upon annealing at temperatures as high as 1400° C. cl EXAMPLE VI [0087] Begin with a mixture of 0.03 at % Mg, 9 at % W and remaining Ni powder. Mix and compact at appropriate pressures into a rod or billet. Then heat treat at 900° C. for 2 hr. During this thermomechanical processing all the Mg is converted to MgO and it is dispersed in a fine and homogeneous manner throughout the preform. The grain size at the end of heat treatment is less than 50 Sm. Deform, by rolling, to a degree greater than 90% total defonnation, preferably using 10% reduction per pass and by reversing the rolling direction during each subsequent pass. Anneal at about 1200° C. for about 60 minutes to produce a sharp biaxial texture. Annealing is performed in flowing 4% H2 in Ar. [0088] [0088]FIG. 21 shows a (11) X-ray diffraction pole figure of the biaxially textured, particulate, S composite substrate As can be seen, only four peaks are evident. Each peak refers to one of four crystallographically similar orientations corresponding to 100<100>, such that the (100) plane is parallel to the surface of the tape and <100> direction is aligned along the long axis of the tape. FIG. 22 shows a phi-scan of the [111] reflection showing the degree of in-plane texture. The FWHM of the tape determined by fitting a gaussian curve to the data is 9.05°. [0089] [0089]FIG. 23 shows the rocking curve or the out-of-plane texture as measured by scanning the [200] reflection of the substrate FIG. 23 is a rocking curve with the sample being rocked in the rolling direction and shows a FWFM of 7.2°. FIG. 24 is a rocking curve with the sample being rocked about the rolling direction and shows a FWHM of 9.040. This is truly a single orientation texture with all crystallographic axis being aligned in all directions within 8-10°. Alloy substrates made by procedures other than what is described above undergo secondary recrystallization at such annealing temperatures and lose most of their biaxial texture. On the contrary, the substrates reported here improve their biaxial textures upon annealing at temperatures as high as 140° C. EXAMPLE VII [0090] Begin with a mixture of 0.03 at % Mg, 9 at % W and remaining Ni powder (99.99% purity). Mix and compact at appropriate pressures into a rod or billet. Then heat treat at 900° C. for 2 hr. During this thermomechanical processing all the Mg is converted to MgO and it is dispersed in a fine and homogeneous manner throughout the preform. The grain size at the end of heat treatment is less than 50 uM. Deform, by rolling, to a degree greater than 90% total deformation, preferably using 10% reduction per pass and by reversing the rolling direction during each subsequent pass. Anneal at about 1400° C. for about 60 minutes to produce a sharp biaxial texture. Annealing is performed in flowing 4% H 2 in Ar. FIG. 25 shows a (111) X-ray diffraction pole figure of the biaxially textured alloy substrate. ‘Ar’ As can be seen, only four peaks are evident. Each peak refers to one of four crystallographically similar orientations corresponding to {100}<100>, such that the (100) plane is parallel to the surface of the tape and <100> direction is aligned along the long axis of the tape. FIG. 26 shows a phi-scan of the [111] reflection showing the degree of in-plane texture. The FWHM of the tape is deterinined by fitting a gaussian curve to the data is 6.1°. FIG. 27 shows the rocking curve or the out-of-plane texture as measured by scanning the [200] reflection of the substrate. FIG. 27 is a rocking curve with the sample being rocked in the rolling direction and shows a FWHM of 6 7°. FIG. 28 is a rocking curve with the sample being rocked about the rolling direction and shows a FWHM of 7.5°. This is truly a single orientation texture with all crystallographic axis being aligned in all direction within 6-7°. Alloy substrates made by procedures other than what is described above undergo secondary recrystallization at such annealing temperatures and lose most of their biaxial texture. On the contrary, the substrates reported here, improve their biaxial textures upon annealing at temperatures as high as 1400° C. EXAMPLE VIII [0091] Begin with a mixture of 0.03 at % Mg, 13 at % Cr and remaining Ni powder. Mix and compact at appropriate pressures into a rod or billet. Then heat treat at 900° C. for 2 hr. During this thermornechanical processing all the Mg is converted to MgO and it is dispersed in a fine and homogeneous manner throughout the preform. The grain size at the end of heat treatment is less than 50 ktm. Deforn, by rolling,, to a degree greater than 90% total defonnation, preferably using 10% reduction per pass and by reversing the rolling direction during each subsequent pass. Anneal at about 1200° C. for about 60 minutes to produce a sharp biaxial texture. Annealing is performed in flowing 4% H 2 in Ar. [0092] [0092]FIG. 29 shows a (11) X-ray diffraction pole figure of the biaxially textured, particulate, composite substrate. As can be seen, only four peaks are evident. Each peak refers to one of four crystallographically similar orientations conresponding to {100}<100>, such that the (100) plane is parallel to the surface of the tape and <100> direction is aligned along the long axis of the tape. FIG. 30 shows a phi-scan of the [111] reflection showing the degree of in-plane texture. The FWHM of the tape detennined by fitting a gaussian curve to the data is 8.06°. [0093] [0093]FIG. 31 shows the rocking curve or the out-of-plane texture as measured by scanning the [200] reflection of the substrate FIG. 31 is a rocking curve with the sample being rocked in the rolling direction and shows a FWHM of 51° FIG. 32 is a rocking curve with the sample being rocked about the rolling direction and shows a FWHM of 9.47°. This is truly a single orientation texture with all crystallographic axis being aligned in all directions within 8-10°. Begin with a mixture of 0.03 at % Mg, 9 at % W and remaining Ni powder (99.99% purity). Mix and compact at appropriate pressures into a rod or billet. Then heat treat at 900° C. for 2 hr. During this thermomechanical processing all the Mg is converted to MgO and it is dispersed in a fine and homogeneous manner throughout the prefoi. The rain size at the end of heat treatment is less than 50 pim. Deform, by rolling, to a degree greater than 90% total deformation, preferably using 10% reduction per pass and by reversing, the rolling direction during each subsequent pass. Anneal at about 1400° C. for about 60 minutes to produce a sharp biaxial texture. Annealing is performed in flowing 4% H 2 in Ar. EXAMPLE IX Begin with a mixture of 0.03 at % Mg, 13 at % Cr and remaining Ni powder (99.99% purity). Mix and compact at appropriate pressures into a rod or billet. Then heat treat at 900° C. for 2 hr. During this thermornechanical processing all the Mg is converted to MgO and it is dispersed in a fine and homogeneous manner throLug(hout the prefonn. The grain size at the end of heat treatment is less than 50 pm. Deform, by rolling, to a degree greater than 90% total deformation, preferably using 10% reduction per pass and by reversing the rolling direction during each subsequent pass. Anneal at about 1400° C. for about 60 minutes to produce a sharp biaxial texture. Annealing is perfonned in flowing 4% H 2 in Ar. [0094] [0094]FIG. 33 shows a (111) X-ray diffraction pole figure of the biaxially textured alloy substrate. As can be seen, only four peaks are evident. Each peak refers to one of four crystallographically similar orientations corresponding to {100}<100>, such that the (100) plane is parallel to the surface of the tape and <100>direction is aligned along the long axis of the tape. FIG. 34 shows a phi-scan of the [11] reflection showing the degree of in-plane texture. The FWHM of the tape is determined by fitting a gaussian curve to the data is 6.5°. FIG. 35 shows the rocking curve or the out-of-plane texture as measured by scanning the [200] reflection of the substrate. FIG. 35 is a rocking curve with the sample being rocked in the rolling direction and shows a FWHM of 6.90. FIG. 36 is a rocking curve with the sample being rocked about the rolling direction and shows a FWHM of 7.9°. This is truly a single orientation texture with all jig crystallographic axis being aligned in all direction within 6-8°. Alloy substrates made by procedures other than what is described above undergo secondary recrystallization at such annealing temperatures and lose most of their biaxial texture. On the contrary, the substrates reported here, improve their biaxial textures upon annealing at temperatures as high as 1400° C. EXAMPLES X [0095] Begin with 99.99% pure Ni powder, and mix in fine (nanocrystalline or microcrystalline) oxide powders such as CeO 2 , Y 203 , and the like. Mix homogeneously and compact to a monolithic form. Defonn, preferably by reverse rolling to a degree of deformnation greater than 90%. Heat treat at temperatures above the primary recrystallization temperature but below the secondary recrystallization temperature to obtain a sharp biaxially textured substrate. Similar experiments with additions of a dispersion and at least one fine metal oxide powder such as but not limited to A 1 2 0 3 , MgO, YSZ, CeO 2 , Y 2 0 3 ., YSZ, and RE 203 ; etc. can be performed with binary alloys of Ni—Cu, Ni—V, Ni—Mo, Ni—Al, and with ternary alloys of Ni—Cr—Al, Ni—W—Al, Ni—V—Al, Ni—Mo—Al, Ni—Cu—Al. Similar results are also expected for 100% Ag and Ag alloys such Ag—Cu, Ag—Pd. PROCEDURES AND EXAMPLES TO OBTAIN AND EFFECTIVELY USE BIAXIALLY TEXTURED ALLOYS WHICH HAVE STACKING FAULT FREQUENCIES GREATER THAN 0.009 AT ROOM TEMPERATURE [0096] In all the following examples, begin with separate powders of the constituents required to form the alloy, mixing them thoroughly and compacting them preferably into the form or a rod or billet. The rod or billet is then deformed, preferably by rolling, at about room temperature or a higher temperature provided the higher temperature is low enough that negligible inter-diffusion of elements occurs. During the initial stages of deformation the larger metal constituent essentially forms a connected and mechanically bonded network. The rod or billet is now rolled to a large degree of deformation, preferably greater than 90%. The alloying element powders i remain as discrete particles in the matrix and may not undergo any significant deformation. Once the deformation is complete, rapidly thermally re-crystallize the substrate to texture the matrix material The alloying elements can be diffused in at a higher temperature after the texture is attained in the matrix. EXAMPLE XI [0097] Begin with 80% Ni and 20% Cr powder. Mix homogeneously and compact to a monolithic form. Heat-treat to low temperatures so as to bond Ni-Ni particles. Since Cr particles are completely surrounded by Ni, their sintering or bonding to the Ni particles is not critical. Deform, preferably by reverse rolling to a degree of deformation greater than 90%. In such a case, the final substrate does not have a homogeneous chemical composition. There are clearly Cr particles dispersed in the matrix. The substrate is now rapidly heated in a furnace to a temperature between the primary and secondary recrystallization of Ni. The objective is to obtain a cube texture in the Ni matrix, with local regions of high Cr concentrations. The aim of the heat treatment is to minimize diffusion of Cr into the Ni matrix. Once the cube texture has been obtained, desired epitaxial oxide, nitride or other buffer layers are deposited on the substrate. Once the first layer is deposited, the substrate can be heat treated at higher temperatures to affect diffusion of Cr into Ni. While high concentrations of Cr of 20 at % in the substrate would result in appearance of secondary texture components, it does not matter at this point what the texture of the underlying metal below the textured ceramic buffer layer is, since further epitaxy is going to occur at the surface of the first ceramic layer. Similar experiments can be perfonned with binary alloys of Ni—Cu, Ni—V, Ni—Mo, Ni—Al, and with ternary alloys of Ni—Cr—Al, Ni—W—Al, Ni—V—Al, Ni—Mo—Al, Ni—Cu—Al. Similar results are also expected for 100% Ag and Ag alloys such Ag—Cu, Ag—Pd. Similar experiments can also be performed with additions of a dispersion of at least one fine metal oxide powder such as but not limited to A 1 2 0 3 , MgO, YSZ, CeO 2 , Y 2 0 3 ,, YSZ, and RE 203 ;etc. with binary alloys of Ni—Cu, Ni—V, Ni—Mo, Ni—Al, and with ternary alloys of Ni—Cr—Al, Ni—W—Al, Ni—V—Al, Ni—Mo—Al, Ni—Cu—Al. Similar results are also expected for 100% Ag and Ag alloys such Ag-Cu, Ag-Pd. While there has been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the scope of the inventions defined by the appended claims

A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the prefonn article having been formed from a powder mixture selected from the group of ternary mixtures consisting of: Ni powder, Cu powder, and Al powder, Ni powder, Cr powder, and Al powder; Ni powder, W powder and Al powder; Ni powder, V powder, and Al powder; Ni powder, Mo powder, and Al powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

[0001] This is a continuation of Application PCT/JP2003/001010, filed on Jan. 31, 2003. BACKGROUND OF THE INVENTION [0002] 1. Technical Field [0003] The present invention relates to a printed wiring board and an electronic apparatus including the printed wiring board. [0004] 2. Background Art [0005] In a printed board on which a high-speed element is mounted, there are problems in that a high frequency current flows into a power supply layer and a ground layer, with the result that resonance occurs and an unnecessary electromagnetic wave is emitted. Up to now, a configuration to which a circuit using a resistor and a magnetic material is added has been employed to suppress the resonance. [0006] However, such a method is disadvantageous in taking measures for packaging in a narrow space. The use of the resistor and the magnetic material increases the number of parts. [0007] Up to now, for resonance measures or noise measures, high-frequency connection is made between the power supply layer and the ground layer through a chip capacitor or the like and charges are supplied to the element. [0008] However, in recent years, with increases in frequency and packaging density in a device, effects obtained by the above-mentioned measures have been reduced due to inductance components of patterns and vias for packaging. In order to prevent this, attention has been focused on a substrate in which flat pattern layers on a circuit board are assumed as electrodes to form a capacitor (buried capacitance board, briefly referred to as a BC board). In addition, it has been proposed to locate a signal layer including a signal line, which is sandwiched by two ground layers (for example, see Patent Document 1 below). [0009] Note that general structures of a multilayer printed board, for example, a via connecting between printed boards, a through hole, a clearance hole for ensuring insulation between the via and the printed board, and the like are described in, for example, Patent Document 2 below. [0000] [Patent Document 1] JP 2001-223449 A [0000] [Patent Document 2] JP 05-152763 A SUMMARY OF THE INVENTION [0010] However, a capacitance of the capacitor of the currently-available buried capacitance board is insufficient. Therefore, there is a problem in that an impedance of about several tens of MHz becomes higher to reduce a bypass effect. Therefore, the following measure methods are expected. [0011] According to a first measure, it is expected to improve a dielectric constant of a dielectric composing the capacitor. However, a material whose dielectric constant is improved is generally expensive. A high dielectric constant material is not easily available in many cases. [0012] According to a second measure, it is expected to reduce a thickness of the dielectric composing the capacitor. However, when the dielectric is too thin, a withstand voltage between the power supply layer and the ground layer reduces and they are short-circuited at worst. In addition, when the dielectric is too thin, handling thereof is hard. [0013] According to a third measure, it is expected to increase an area of the capacitor. This corresponds to an increase in area of the printed board or an increase in area of a capacitor portion in the printed board. However, because of a limitation of size of a device, the area of the capacitor portion in the printed board is limited in many cases. [0014] The present invention has been made in view of such problems of the conventional technologies. That is, an object of the present invention is to improve characteristics of the buried capacitance board. [0015] More specifically, an object of the present invention is to improve a capacitance of a capacitor in a packaging method using the buried capacitance board. Further, an object of the present invention is to suppress a board resonance phenomenon in a packaging method using the buried capacitance board. [0016] In order to achieve the above-mentioned objects, the present invention adopts the following measures. That is, the present invention relates to a multilayer printed board, including: [0017] a plurality of capacitive coupling layers, each of which includes a power supply layer and a ground layer which are opposed to each other and a dielectric layer which is sandwiched therebetween; [0018] a first via that connects between the power supply layers included in the plurality of capacitive coupling layers; and [0019] a second via that connects between the ground layers included in the plurality of capacitive coupling layers. [0020] Therefore, according to the present invention, the plurality of capacitive coupling layers are provided, the power supply layers included in the respective capacitive coupling layers are connected with each other, and the ground layers included in the respective capacitive coupling layers are connected with each other. Thus, a capacitance of each of the capacitive coupling layers can be increased to reduce an impedance in a low frequency domain in which a frequency is low. [0021] Preferably, in the multilayer printed board, a power supply via that connects a power supply terminal of an element with the power supply layers may be formed near a central axis passing through a substantially central portion of a flat region of each of the capacitive coupling layers. [0022] Alternatively, the present invention may relate to a multilayer printed board, including: [0023] a capacitive coupling layer that includes a power supply layer and a ground layer which are opposed to each other and a dielectric layer which is sandwiched therebetween; [0024] an element layer on which an element to which power is supplied from the power supply layer is mounted; and [0025] a via that is formed close to a central axis passing through substantially a central portion of a flat region of the capacitive coupling layer and connects a power supply terminal of the element with the power supply layer. [0026] Therefore, the multilayer printed board of the present invention has a via which is located near the central axis passing through the substantially central portion of the flat region of the capacitive coupling layer. A power supply terminal of the element is connected with the power supply layer. The element is desirably an element having a high-speed operating frequency in multilayer printed board. A high frequency wave is supplied from the element to the power supply layer through the via. However, the via is formed near the central axis, so that resonance dependent on a size of the capacitive coupling layer can be reduced. [0027] Preferably, the number of at least one of the first via and the second via is two or more. Therefore, when the number of at least one of the first via and the second via is set to two or more, resonance points of which the number increases with an increase in capacitance of the capacitive coupling layer can be shifted to a high frequency side. [0028] Preferably, the power supply layer and the ground layer in each of the plurality of capacitive coupling layers may be laminated in the same arrangement order. [0029] Preferably, the power supply layer and the ground layer in a first capacitive coupling layer of the plurality of capacitive coupling layers may be laminated in an arrangement order reverse to an arrangement order of those in a second capacitive coupling layer thereof. That is, the present invention has no limitations on the arrangement order of the power supply layer and the ground layer. [0030] Preferably, the power supply layer and the ground layer may form a capacitive coupling layer over an entire region of the dielectric layer. [0031] Preferably, the power supply layer and the ground layer may form a capacitive coupling layer in a partial region of the dielectric layer. [0032] Preferably, a flat shape of at least one of the power supply layer and the ground layer may be substantially a regular polygon having sides whose number is equal to or larger than five. [0033] Preferably, a flat shape of at least one of the power supply layer and the ground layer may be substantially a circle. [0034] Preferably, a ratio of a longest distance to a shortest distance between a central portion and a peripheral portion of a flat shape of at least one of the power supply layer and the ground layer thereof is 1 to 1.41. [0035] According to the present invention, any structure described above may be used for an electronic apparatus provided with a multilayer printed board. [0036] As described above, according to the present invention, the characteristics of the capacitive coupling layer can be improved to shift the resonance point to a high frequency domain. BRIEF DESCRIPTION OF THE DRAWINGS [0037] FIG. 1 is a perspective view showing a multilayer printed board according to a first embodiment mode of the present invention; [0038] FIG. 2 is a front view showing the multilayer printed board according to the first embodiment mode of the present invention; [0039] FIG. 3 is a front view showing an analytical model of a multilayer printed board according to Embodiment 1; [0040] FIG. 4 is a plan view showing positions of a power supply pin of an LSI 1 , power supply vias 7 A and 7 B, and ground vias 8 , which are mounted on the multilayer printed board according to Embodiment 1; [0041] FIG. 5 shows an impedance analytical result of a BC board 6 shown in FIG. 4 ; [0042] FIG. 6 shows an impedance analytical result ( 1 ) in the case where the number of BC layers 6 is changed; [0043] FIG. 7 shows an impedance analytical result ( 2 ) in the case where the number of BC layers 6 is changed; [0044] FIG. 8 shows the position of the power supply pin of the LSI 1 (power supply via 7 A) and the positions of the power supply vias 7 B and the ground vias 8 in Embodiment 2; [0045] FIG. 9 shows a frequency characteristic of an impedance of the BC layer 6 in Embodiment 2; [0046] FIG. 10 shows the position of the power supply pin of the LSI 1 (power supply via 7 A) and the positions of the power supply vias 7 B and the ground vias 8 in Embodiment 3; [0047] FIG. 11 shows a frequency characteristic of an impedance of the BC layer 6 in Embodiment 3; [0048] FIG. 12 is a perspective view showing a multilayer printed board according to a modified example of the first embodiment mode; [0049] FIG. 13 is a front view showing the multilayer printed board according to the modified example of the first embodiment mode; [0050] FIG. 14 is a perspective view showing a multilayer printed board according to a second embodiment mode; [0051] FIG. 15 is a front view showing the multilayer printed board according to the second embodiment mode; [0052] FIG. 16 is an explanatory view of a natural resonance frequency of a printed board; [0053] FIG. 17 shows a summary of Embodiment 4 of the present invention; [0054] FIG. 18 shows superposition of results obtained by measurement in Embodiment 4; [0055] FIG. 19 shows an analytical result ( 1 ) of a current distribution; [0056] FIG. 20 shows an analytical result ( 2 ) of a current distribution; [0057] FIG. 21 shows an analytical result ( 3 ) of a current distribution; [0058] FIG. 22 shows an analytical result ( 4 ) of a current distribution; [0059] FIG. 23 shows an analytical result ( 5 ) of a current distribution; [0060] FIG. 24 shows an analytical result ( 6 ) of a current distribution; [0061] FIG. 25 shows respective states of the BC layer 6 in the case where the power supply via 7 (power supply pin 17 of the LSI 1 ) is shifted from a central position in the direction of a side of a rectangle composing the BC layer; [0062] FIG. 26 shows a result obtained by analyzing horizontal polarization of a radiation electric field strength with respect to the respective states shown in FIG. 25 ; [0063] FIG. 27 shows a result obtained by analyzing vertical polarization of a radiation electric field strength with respect to the respective states shown in FIG. 25 ; [0064] FIG. 28 shows respective states of the BC layer 6 in the case where the power supply via 7 (power supply pin 17 of the LSI 1 ) is shifted from the central position in a vertex direction of the rectangle composing the BC layer; [0065] FIG. 29 shows a result obtained by analyzing horizontal polarization of a radiation electric field strength with respect to the respective states shown in FIG. 28 ; [0066] FIG. 30 shows a result obtained by analyzing vertical polarization of a radiation electric field strength with respect to the states shown in FIG. 28 ; [0067] FIG. 31 shows a multilayer printed board having the BC layer 6 with a rectangular shape of 25 mm square; [0068] FIG. 32 shows a result ( 1 ) obtained by analyzing horizontal polarization of a radiation electric field strength with respect to the multilayer printed board shown in FIG. 31 ; [0069] FIG. 33 shows a result ( 1 ) obtained by analyzing vertical polarization of a radiation electric field strength with respect to the multilayer printed board shown in FIG. 31 ; [0070] FIG. 34 shows a result ( 2 ) obtained by analyzing horizontal polarization of a radiation electric field strength with respect to the multilayer printed board shown in FIG. 31 ; [0071] FIG. 35 shows a result ( 2 ) obtained by analyzing vertical polarization of a radiation electric field strength with respect to the multilayer printed board shown in FIG. 31 ; [0072] FIG. 36 is a perspective view showing a multilayer printed board according to a third embodiment mode of the present invention; [0073] FIG. 37 is a front view showing the multilayer printed board according to the third embodiment mode of the present invention; [0074] FIG. 38 shows comparison between the BC layer 16 in the third embodiment mode and the BC layer in the first embodiment mode or the second embodiment mode; [0075] FIG. 39 shows impedance analytical results in the case where the power supply via 7 is located near a central axis of a rectangular BC layer of 50 mm square and in the case where the power supply via 7 is located near a central axis of a circular BC layer 16 having a diameter of 50 mm; [0076] FIG. 40 shows BC layers each having a flat shape of a regular polygon such as a regular octagon, a regular hexadecagon, or a regular triacontakaidigon; [0077] FIG. 41 shows frequency characteristics with respect to an impedance between the power supply layer and the ground layer in each of the BC layers each having a flat shape such as a square, the regular octagon, the regular hexadecagon, or the regular triacontakaidigon; [0078] FIG. 42 shows an analytical result ( 1 ) of a current density in a rectangular BC layer at a vicinity of a resonance point; [0079] FIG. 43 shows an analytical result ( 2 ) of a current density in the rectangular BC layer in the vicinity of the resonance point; [0080] FIG. 44 shows a current distribution of a high frequency current in an octagonal BC layer; [0081] FIG. 45 shows a current distribution of a high frequency current in a triacontakaidigonal BC layer; [0082] FIG. 46 shows an analytical result of a radiation electric field strength in rectangular, regular octagonal, regular hexadecagonal, and regular triacontakaidigonal BC layers at the time of resonance; [0083] FIG. 47 shows a structure of an electric apparatus 100 according to a fourth embodiment mode of the present invention; [0084] FIG. 48 shows a shape of the BC layer according to a modified example of the first to third embodiment modes; [0085] FIG. 49 shows a layer structure of an analytical model of a multilayer print according to the second and third embodiment modes; and [0086] FIG. 50 shows observation points for the radiation electric field strength in the analytical mode of the multilayer print according to the second and third embodiment modes. DETAILED DESCRIPTION OF THE INVENTION [0087] Hereinafter, preferred embodiment modes of the present invention will be described with reference to the drawings. First Embodiment Mode [0088] Hereinafter, a multilayer printed board according to a first embodiment mode of the present invention will be described with reference to FIG. 1 to FIG. 13 . [0000] <Structure> [0089] FIG. 1 is a perspective view showing an example of the multilayer printed board. FIG. 2 is a front view in the case where the multilayer printed board is viewed from a direction indicated by an arrow A in FIG. 1 . As shown in FIG. 1 or FIG. 2 , the multilayer printed board includes an element such as an LSI 1 , printed boards 2 - 1 , 2 - 2 , and 2 - 3 , each of which has a signal layer connected with the element, and BC layers 6 located between the printed boards 2 - 1 and 2 - 2 and the printed boards 2 - 2 and 2 - 3 . [0090] The printed boards 2 - 1 , 2 - 2 , 2 - 3 , etc. each are composed of a single or plural printed boards. In the case of plural items, they are referred to as multiple layers 2 - 1 , 2 - 2 , 2 - 3 , etc. In general, each of the printed boards 2 - 1 , 2 - 2 , 2 - 3 , etc. includes a conductive layer (this is referred to as the signal layer) connected with the element such as the LSI 1 . [0091] The BC layers 6 each are composed of a power supply layer 3 , a thin film dielectric 4 , and a ground layer 5 . [0092] The power supply layer 3 is connected with a power supply located outside the multilayer printed board and used to supply power to the element mounted on the multilayer printed board. The power supply layer 3 is formed from a metallic thin film formed into a rectangular sheet. The metallic thin film is also referred to as a flat pattern layer. A copper thin film is generally used as a metallic film composing the power supply layer 3 . Note that a metal such as aluminum, silver, platinum, and gold may be used if necessary. [0093] The ground layer 5 is connected with an earth located outside the multilayer printed board and used as a layer for grounding the element mounted on the multilayer printed board. As in the case of the power supply layer 3 , the ground layer 5 is formed from a metallic thin film made of copper or the like. The ground layer is also formed into a rectangular sheet and referred to as a flat pattern layer. [0094] The thin film dielectric 4 is a dielectric layer inserted between the power supply layer 3 and the ground layer 5 . The thin film dielectric 4 is used to increase a dielectric constant of a portion sandwiched between the power supply layer 3 and the ground layer 5 to improve a function as a capacitor. Such a board which is composed of the power supply layer 3 , the thin film dielectric 4 , and the ground layer 5 is known as a buried capacitance board (or a BC board). [0095] In this embodiment mode, for example, polyimide, Fr-4 (glass epoxy), or ceramic can be used for the thin film dielectric 4 . [0096] The multilayer printed board according to this embodiment mode has the plurality of BC layers 6 (two BC layers 6 are shown in FIG. 1 and FIG. 2 ). [0097] As shown in FIG. 2 , the power supply layers 3 included in the respective BC layers 6 are connected with each other through a power supply via 7 . The power supply via 7 passes through the uppermost printed board 2 - 1 including the signal layer and is connected with a power supply pin of the LSI 1 . [0098] In general, when the via is formed, a hole is formed in the printed board (metallic thin film and the dielectric which is its lower layer) and an inner wall of the hole is coated with a metal. The via is used to connect, for example, between the printed board 2 - 1 and another printed board, between the printed board 2 - 1 and the power supply layer 3 , or between the printed board 2 - 1 and the ground layer 5 . The LSI 1 is located on the printed board 2 - 1 such that the power supply pin thereof is adjacent to the power supply via 7 . [0099] With respect to the printed boards 2 - 1 , 2 - 2 , and 2 - 3 , the power supply layer 3 , or the ground layer 5 , which are not connected with the via, a hole having a shape larger than an outer diameter of the via (this is referred to as a clearance hole) is provided at a position in which the via is formed. [0100] Therefore, an arbitrary layer included in the multilayer printed board can be connected with another layer by a combination of the via and the clearance hole (for example, see Patent Document 2 above). In this embodiment mode, an outer diameter (diameter of a conductor surface which is in contact with the hole of the printed board) of the power supply via 7 is 0.3 millimeters and an inner diameter of the clearance hole is about 0.9 millimeters. [0101] As shown in FIG. 2 , the ground layers 5 included in the respective BC layers 6 are connected with each other through a ground via 8 to ground the printed board 2 - 1 , 2 - 2 , or 2 - 3 and the element (such as the LSI 1 ). [0102] When such a structure is used for the multilayer printed board according to this embodiment mode, the plurality of power supply layers 3 are connected with each other through the power supply via 7 . In addition, in the multilayer printed board, the plurality of ground layers 5 are connected with each other through the ground via 8 . [0103] Thus, according to the multilayer printed board of the present invention, a sufficient capacitance is ensured in each of the BC boards 6 . In this multilayer printed board, the power supply via 7 or the ground via 8 is not limited to a single via. That is, in the multilayer printed board of the present invention, a plurality of power supply vias 7 or a plurality of ground vias 8 are provided to improve a frequency characteristic of each of the BC boards 6 . Embodiment 1 [0104] FIG. 3 and FIG. 4 show a structure of a multilayer printed board according to Embodiment 1 of the present invention. In this embodiment, numerical analytical results obtained by calculation of a modeled multilayer printed board are shown. FIG. 3 is a front view showing an analytical model in the case where the multilayer printed board is viewed from the front (for example, the direction indicated by the arrow A in FIG. 1 ) as in FIG. 2 . [0105] As shown in FIG. 3 , the multilayer printed board includes an insulator 2 A, a power supply layer 3 - 1 , a thin film dielectric 4 - 1 , a ground layer 5 - 1 , an insulator 2 B, a power supply layer 3 - 2 , a thin film dielectric 4 - 2 , a ground layer 5 - 2 , and an insulator 2 C. Note that a signal layer is formed on an upper side of the insulator 2 A or a lower side of the insulator 2 B in an original multilayer printed board. In this embodiment, the influence of the signal layer is not considered for the simplification of the model. [0106] Each of the insulators 2 A and 2 C is a dielectric which has a dielectric constant of 3.2 and a thickness of 50 micrometers. The insulator 2 B is a dielectric which has a dielectric constant of 3.2 and a thickness of 100 micrometers. Each of the thin film dielectrics 4 - 1 and 4 - 2 is a dielectric which has a dielectric constant of 3.2 and a thickness of 25 micrometers. In FIG. 3 , the dielectric constant is shown by symbol Er. [0107] In Embodiment 1 of the present invention, the power supply layer 3 - 1 and the power supply layer 3 - 2 are connected with each other through a power supply via 7 B. The ground layer 5 - 1 and the ground layer 5 - 2 are connected with each other through a ground via 8 . [0108] The power supply via 7 B is a copper wire that connects the power supply layer 3 - 1 with the power supply layer 3 - 2 and has a diameter of 0.3 mm and conductivity of 5.977286×10 7 . The ground via 8 is a copper wire that connects the ground layer 5 - 1 with the ground layer 5 - 2 and has a diameter of 0.3 mm and conductivity of 5.977286×10 7 . [0109] A clearance hole having a rectangular shape of 0.98 mm square is provided around each of the vias in layers which are not connected with the vias (power supply via 7 B and ground via 8 ). Assume that air surrounds the multilayer printed board. [0110] A virtual wave source (high frequency voltage source) is set between the power supply layer 3 - 1 and the ground layer 5 - 1 and a current flowing thereinto is calculated. At this time, a via that connects the wave source with the power supply layer 3 - 1 and the ground layer 5 - 1 is referred to as a power supply via 7 A. The power supply via 7 A is originally a via that connects the power supply pin of the LSI 1 with the power supply layer 3 - 1 . However, in order to simply calculate an impedance between the power supply layer 3 - 1 and the ground layer 5 - 1 , the wave source is set between the power supply layer 3 - 1 and the ground layer 5 - 1 . [0111] Here, a high frequency signal from the wave source is a trapezoid waveform whose rise time and fall time are each 500 ps, whose period is 100 MHz, and whose amplitude is 3.3 volts. In the analysis in this embodiment mode, various high frequency signals are inputted based on Fourier spectrum of the trapezoid waveform. [0112] FIG. 4 is a plan view showing positions of the power supply pin of the LSI 1 , the power supply vias 7 A and 7 B, and the ground via 8 , which are mounted on the multilayer printed board (view in the case where the multilayer printed board is viewed from a direction indicated by an arrow B in FIG. 3 ). Note that FIG. 4 shows five cases (V 1 G 1 - 1 to V 1 G 1 - 5 ) in which the positions of the power supply via 7 B and the ground via 8 are shifted. [0113] In FIG. 4 , any case of V 1 G 1 - 1 to V 1 G 1 - 5 , the power supply pin of the LSI 1 is positioned in a central portion of the BC layer 6 . As described above, in the multilayer printed board according to Embodiment 1, the power supply via 7 A and the wave source are formed just below the power supply pin and between the power supply layer 3 - 1 and the ground layer 5 - 1 (see FIG. 3 ). [0114] Each of five heavy rectangles indicated by V 1 G 1 - 1 to V 1 G 1 - 5 shows an existing region of the BC layer 6 and is a rectangle of 25 millimeters square. [0115] In FIG. 4 , mesh portions within each of the heavy rectangles indicated by V 1 G 1 - 1 to V 1 G 1 - 5 (such as M 1 and M 2 ) show element regions for numerical analysis. Note that the reason why each of the mesh portions in the four corners of each of the heavy rectangles (V 1 G 1 - 1 to V 1 G 1 - 5 ) is divided into two triangles as in the case of M 2 is to ensure analytical precision. [0116] V 1 G 1 - 1 shows the case where the power supply via 7 B and the ground via 8 are provided on the left side of the power supply pin of the LSI 1 . Here, the left side is the left in the case where FIG. 4 is viewed from the front (hereinafter, the right side, the upper side, and the lower side are the same as above). [0117] V 1 G 1 - 2 shows the case where the power supply via 7 B and the ground via 8 are further added on the right side of the power supply pin of the LSI 1 as compared with the case V 1 G 1 - 1 . [0118] V 1 G 1 - 3 shows the case where the power supply via 7 B and the ground via 8 are further added on the upper side of the power supply pin of the LSI 1 as compared with the case V 1 G 1 - 2 . [0119] V 1 G 1 - 4 shows the case where the power supply via 7 B and the ground via 8 are further added on the lower side of the power supply pin of the LSI 1 as compared with the case V 1 G 1 - 3 . [0120] V 1 G 1 - 5 shows the case where the two power supply vias 7 B and the two ground vias 8 are further added as compared with the case V 1 G 1 - 4 . [0121] FIG. 5 shows an analytical result of an impedance of the BC board 6 (between the power supply layer 3 and the ground layer 5 ) in the five cases (V 1 G 1 - 1 to V 1 G 1 - 5 ) as shown in FIG. 4 . [0122] This analytical result is obtained by applying the electromagnetic analysis program ACCUFIELD® produced by FUJITSU LIMITED to the analytical model shown in FIG. 3 and FIG. 4 . The ACCUFIELD® is an electromagnetic analysis program in which a piecewise sinusoidal moment method (also called a moment method) is combined with a distributed constant transmission line theory. [0123] In this numerical analysis, a rectangular sheet of 25 mm square (conductor sheet having conductivity of 5.977286×10 7 ) is provided for each of the power supply layers 3 - 1 and 3 - 2 and the ground layers 5 - 1 and 5 - 2 as shown in FIG. 3 . Each rectangular sheet is divided into, for example, the mesh portions M 1 and M 2 shown in FIG. 4 . [0124] A high frequency power supply is set to a position of the wave source shown in FIG. 3 to obtain currents flowing through the respective mesh portions of each layer (each rectangular sheet) through the power supply vias 7 A and 7 B and the ground via 8 . [0125] As described above, in this embodiment, the currents are calculated by the electromagnetic analysis program run on a computer. In a structure in which the single BC layer 6 is used, the power supply layer is connected with the power supply via, and the ground layer is connected with the ground via, a result is obtained in which values obtained by analysis using the electromagnetic analysis program coincide with measured values. [0126] FIG. 5 shows an impedance analytical result. In FIG. 5 , the abscissa indicates a frequency and the ordinate indicates an impedance. Here, analytical results with respect to the respective analytical models V 1 G 1 - 1 to V 1 G 1 - 5 shown in FIG. 4 are shown using different graphs. [0127] As shown in FIG. 5 , each of the models V 1 G 1 - 1 to V 1 G 1 - 5 exhibits a W-shaped characteristic or a characteristic in which a plurality of V-shapes are connected with one another. For example, in the case of V 1 G 1 - 1 , the impedance characteristic starts from a left end point S 1 and falls down to a lower right position P 1 in a frequency range of about 50 MHz to 210 MHz. [0128] Next, the impedance characteristic rises up to an upward position P 2 in a frequency range of about 210 MHz to 350 MHz. Then, the impedance characteristic falls down to a downward position P 3 in a frequency range of about 350 MHz to about 650 MHz. Then, the impedance characteristic rises up to P 4 in a frequency range of about 650 MHz to 850 MHz. [0129] In the impedance characteristic, each of peaks such as P 1 , P 2 , and P 3 indicates a resonance point. In general, when an element is mounted on a board, it is desirable to avoid the use of an element having an operating frequency (for example, a clock cycle) close to a resonance frequency because this becomes a cause of malfunction or the like. [0130] For example, in the multilayer printed board including the BC layer 6 having the impedance characteristic shown in FIG. 5 , an element having a clock cycle of a range of S 1 to P 1 , P 2 to P 3 , or P 4 to P 5 is used. This is because each range is a capacitive domain in which the impedance reduces with an increase in frequency, so that characteristics are similar to one another. [0131] For example, an element having a clock cycle of a range of P 1 to P 2 or P 3 to P 4 may be used. This is because each range is an inductive domain in which the impedance increases with an increase in frequency, so that characteristics are similar to one another. However, it is impossible to use an element having a frequency close to the peak such as P 1 , P 2 , P 3 , P 4 , P 5 , or P 6 (particularly, a frequency in a domain slightly lower than P 2 or P 4 ). This is because the dependence of the impedance on the frequency is significant in the domain. [0132] As is apparent from FIG. 5 , the resonance point is shifted to a higher frequency domain (toward a higher frequency direction) with changing from V 1 G 1 - 1 to V 1 G 1 - 5 . For example, a first resonance point in V 1 G 1 - 5 is Q 1 . The resonance point Q 1 corresponds to the resonance point P 1 in V 1 G 1 - 1 . [0133] In addition, a second resonance point in V 1 G 1 - 5 is Q 2 . The resonance point Q 2 corresponds to the resonance point P 2 in V 1 G 1 - 1 . Therefore, a band of about 400 MHz is ensured up to the first resonance point Q 1 . A band of a frequency which exceeds 400 MHz (about 410 MHz to about 820 MHz) is ensured in a domain from the first resonance point Q 1 to the next resonance point Q 2 . [0134] FIG. 6 and FIG. 7 show reference characteristics in the case where the number of BC layers 6 is changed. These reference characteristics are used to check characteristics caused due to changes in the number of BC layers 6 . Therefore, as compared with the case of FIG. 5 , an analytical condition is not identical and a resonance frequency is different. [0135] FIG. 6 shows two impedance characteristics indicated by character strings “single layer” and “two layers”. The “two layers” indicates an analytical result of an impedance characteristic in the case of the structure in Embodiment 1 ( FIG. 3 ). [0136] On the other hand, the “single layer” indicates an impedance characteristic in the case where one of the BC layers 6 is removed from the structure in Embodiment 1. In this case, the power supply via 7 B for connecting between the power supply layers 3 - 1 and 3 - 2 and the ground via 8 for connecting between the ground layers 5 - 1 and 5 - 2 do not exist. [0137] As shown in FIG. 6 , in the case of the single layer, a first resonance point R 1 occurs at about 200 MHz and a second resonance point R 2 occurs at about 1500 MHz. On the other hand, in the case of the two layers, a first resonance point P 1 occurs at about 150 MHz and the second resonance point P 2 occurs at about 700 MHz. [0138] As is apparent from FIG. 6 , a capacitive impedance characteristic in the case of the two BC layers 6 reduces in a low frequency domain (about 50 MHz to about 150 MHz in FIG. 6 ) as compared with the case of the single BC layer. This indicates an increase in capacitance of each of the BC layers 6 serving as capacitors because the two power supply layers 3 are connected with each other through the power supply via 7 B and the two ground layers 5 are connected with each other through the ground via 8 . [0139] In FIG. 6 , the impedance characteristic in the case of the two BC layers 6 appears to increase in an inductance band which exceeds 200 MHz (vicinity of the resonance point R 1 in the case of the single layer) as compared with the case of the single layer. This is because an apparent impedance in the case of the single layer is reduced by the presence of the resonance point R 1 in the case of the single layer. Therefore, in a domain sufficiently apart from the resonance point R 1 to a high frequency side, an inductive impedance in the case of the two layers is substantially equal to that in the case of the single layer. [0140] On the other hand, as shown in FIG. 6 , a band up to the resonance point in the case of the two layers is narrower than that in the case of the single layer. For example, the resonance point P 1 in the case of the two layers is closer to a low frequency side than the resonance point R 1 in the case of the single layer. [0141] FIG. 7 shows a comparative result between the case of the single layer, the case of the two layers, and the case of four layers, for the purpose of reference. The “four layers” shows an analytical result in the case where the four BC layers 6 are used. Note that an analytical condition in FIG. 7 is different from that related to the analytical result in the case of FIG. 6 , so that a resonance frequency is different from that in the case of FIG. 6 . Therefore, absolute frequency comparison cannot be made between FIG. 6 and FIG. 7 . [0142] As shown in FIG. 7 , in the case of the four layers, a first resonance point T 1 occurs at about 60 MHz and a second resonance point T 2 occurs at about 120 MHz. In the case of the two layers, the first resonance point P 1 occurs at about 110 MHz and the second resonance point P 2 occurs at about 200 MHz. In the case of the single layer, the first resonance point R 1 occurs at about 190 MHz. [0143] In the case of FIG. 7 , an impedance in a conductive domain up to each of the first resonance points (T 1 , P 1 , and R 1 ) reduces as the number of layers increases as in the case of FIG. 6 . This indicates an increase in capacitance of a capacitor by parallel connection of the BC layers 6 . [0144] A band width up to the resonance point (for example, a band up to each of the first resonance points T 1 , P 1 , and R 1 ) becomes narrower as the number of layers increases. This is possibly because a new resonance mode is caused by the parallel connection of the BC layers 6 . [0145] As described above, according to the structure in this embodiment, the plurality of power supply layers 3 are connected with each other through the power supply via 7 B and the plurality of ground layers 5 are connected with each other through the ground via 8 . Therefore, it is possible to increase a capacitance of each of the BC layers 6 serving as capacitors. [0146] In this case, the band up to each of the resonance points becomes narrower as the number of layers increases. However, as shown in FIG. 5 , when the number of power supply vias 7 B and the number of ground vias 8 increase, each of the resonance points can be shifted to the high frequency side. That is, according to the multilayer printed board in this embodiment, when the plurality of BC layers 6 are connected with each other, it is possible to reduce the low frequency side impedance. Further, when the number of vias increases, the resonance point can be shifted to the high frequency domain to widen a band width. Embodiment 2 [0147] FIG. 8 and FIG. 9 show Embodiment 2. In Embodiment 1, the number of power supply vias 7 B is made equal to the number of ground vias 8 . They are increased from one set (V 1 G 1 - 1 ) to five sets (V 1 G 1 - 5 ) by one and the impedance characteristic of the BC layers 6 are calculated. In Embodiment 2, a ratio between the number of power supply vias 7 B and the number of ground vias 8 is set to 1:2. Such a combination is increased from one set to four sets and the impedance characteristic of the BC layers 6 are calculated. Other structures are identical to those in Embodiment 1. [0148] FIG. 8 shows the position of the power supply pin of the LSI 1 (power supply via 7 A) and the positions of the power supply vias 7 B and the ground vias 8 in this embodiment. As shown in FIG. 8 , even in any of V 1 G 2 - 1 to V 1 G 2 - 4 , a pair of ground vias 8 are provided on both sides of each of the power supply vias 7 to make one set. [0149] In the case of V 1 G 2 - 1 , the one set is provided on the left side of the power supply pin of the LSI 1 . In the case of V 1 G 2 - 2 , the one set is further provided on the right side of the power supply pin of the LSI 1 as compared with the case of V 1 G 2 - 1 . In the case of V 1 G 2 - 3 , the one set is further provided on the upper side of the power supply pin of the LSI 1 as compared with the case of V 1 G 2 - 2 . In the case of V 1 G 2 - 4 , the one set is further provided on the lower side of the power supply pin of the LSI 1 as compared with the case of V 1 G 2 - 3 . [0150] FIG. 9 shows a frequency characteristic of an impedance of the BC layers 6 . Even in FIG. 9 , the characteristic of the impedance of the BC layers 6 is similar to that shown in FIG. 5 . That is, as is apparent from the cases V 1 G 2 - 1 to V 1 G 2 - 4 , when the number of sets of the power supply via 7 B and the ground via 9 increases, the resonance point is shifted to the high frequency domain to widen the band width. Embodiment 3 [0151] FIG. 10 and FIG. 11 show Embodiment 3. In Embodiment 1, the number of power supply vias 7 B is made equal to the number of ground vias 8 . They are increased from one set (V 1 G 1 - 1 ) to five sets (V 1 G 1 - 5 ) by one and the impedance characteristic of the BC layers 6 are calculated. In Embodiment 2, the ratio between the number of power supply vias 7 B and the number of ground vias 8 is set to 1:2 and the same analysis is performed. [0152] In Embodiment 3, the ratio between the number of power supply vias 7 B and the number of ground vias 8 is set to 1:3. Such a combination is increased from one set to four sets and the impedance characteristic of the BC layers 6 are calculated. Other structures are identical to those in Embodiment 1 or 2. [0153] FIG. 10 shows the position of the power supply pin of the LSI 1 (power supply via 7 A) and the positions of the power supply vias 7 B and the ground vias 8 in this embodiment. As shown in FIG. 10 , even in any of V 1 G 3 - 1 to V 1 G 3 - 4 , the ground vias 8 are provided on three sides of each of the power supply vias 7 B to make one set. In this case, a set in which the ground vias 8 are provided on the left, right, and lower sides of the power supply via 7 B is referred to as a type 1 . A set in which the ground vias 8 are provided on the left, right, and upper sides of the power supply via 7 B is referred to as a type 2 . [0154] In the case of V 1 G 3 - 1 , the set of the type 1 is provided on the left side of the power supply pin of the LSI 1 . In the case of V 1 G 3 - 2 , the set of the type 2 is further provided on the right side of the power supply pin of the LSI 1 as compared with the case of V 1 G 3 - 1 . In the case of V 1 G 3 - 3 , the set of the type 2 is further provided on the upper side of the power supply pin of the LSI 1 as compared with the case of V 1 G 3 - 2 . In the case of V 1 G 3 - 4 , the set of the type 1 is further provided on the lower side of the power supply pin of the LSI 1 as compared with the case of V 1 G 3 - 3 . [0155] FIG. 11 shows a frequency characteristic of an impedance of the BC layers 6 . Even in FIG. 11 , the characteristic of the impedance of the BC layers 6 is similar to that shown in FIG. 5 or FIG. 9 . That is, as is apparent from the cases of V 1 G 3 - 1 to V 1 G 3 - 4 , when the number of sets of the power supply via 7 B and the ground via 9 increases, the band width widens. [0000] <Modified Example> [0156] In the first embodiment mode, as shown in FIG. 1 or FIG. 2 , each of the BC layers is composed of the power supply layer 3 , the thin film dielectric 4 , and the ground layer 5 . The multilayer printed board is constructed based on this order (for example, the order in which the power supply layer 3 , the thin film dielectric 4 , and the ground layer 5 are provided as viewed from the printed board (multiple layers) 2 - 1 in FIG. 2 ). [0157] However, the embodiment of the present invention is not limited to such a structure. For example, a positional relationship between the power supply layer 3 and the ground layer 5 may be arbitrarily changed in the BC layer 6 . [0158] FIG. 12 and FIG. 13 show an example of such a multilayer printed board. FIG. 12 is a perspective view showing a modified example of the multilayer printed board according to the first embodiment mode. FIG. 13 is a front view showing the multilayer printed board viewed from a direction indicated by an arrow C in FIG. 12 . [0159] In this example, the multilayer printed board includes two BC boards 6 A and 6 B. The BC board 6 A has the power supply layer 3 , the thin film dielectric 4 , and the ground layer 5 which are provided in this order as viewed from the printed board (multiple layers) 2 - 1 . The BC board 6 B has the ground layer 5 , the thin film dielectric 4 , and the power supply layer 3 which are provided in this order as viewed from the printed board (multiple layers) 2 - 1 . With respect to the plurality of BC layers 6 A and 6 B, the power supply layers 3 are connected with each other through the power supply via 7 B and the ground layers 8 are connected with each other through the ground via 8 . Even when the BC layers 6 A and 6 B are constructed as described above, an analytical result is identical to the results shown in FIGS. 5 to 7 , 9 , and 11 . [0160] Even when the multilayer printed board includes over two BC layers 6 , the order in which the power supply layer 3 and the ground layer 5 are provided in the BC layer 6 is not limited. That is, even in an arbitrary combination of the BC layers 6 A and 6 B as shown in FIG. 12 , the impedance characteristic is not significantly different from that in the case where a plurality of any one of the BC layer 6 A and 6 B are combined as in the first embodiment mode. [0161] In the first embodiment mode, the BC layers 6 and other layers such as the printed boards 2 - 1 and 2 - 2 are formed in substantially the same shape. However, the embodiment of the present invention is not limited to the same shape. [0162] FIG. 48 shows a modified example of the multilayer printed board according to this embodiment mode in the case where it is viewed from the upper side (for example, in the direction indicated by the arrow B in FIG. 3 ). As shown in FIG. 48 , a size of the BC layer 6 may be smaller than sizes of the other printed boards. That is, a metallic coating portion 3 A of the power supply layer 3 may be formed in a portion of a board composing the power supply layer 3 and a metallic coating portion 5 A of the ground layer may be formed in a portion of a board composing the ground layer 5 . This applies to the case where the BC layer is provided only in the vicinity of the specific LSI 1 . Therefore, even when a portion of the multilayer printed board composes the BC layer 6 , the present invention can be implemented. [0163] That is, the plurality of power supply layers 3 included in the multilayer printed board may be connected with each other through the power supply via 7 B. The plurality of ground layers 5 included in the multilayer printed board may be connected with each other through the ground via 8 . Second Embodiment Mode [0164] Hereinafter a multilayer printed board according to a second embodiment mode of the present invention will be described with reference to FIG. 14 to FIG. 35 . The first embodiment mode shows the impedance characteristic of the multilayer printed board in which the power supply layers 3 included in the plurality of BC layers 6 are connected with each other through the power supply via 7 ( 7 B) and the ground layers 5 included in the plurality of BC layers 6 are connected with each other through the ground via 8 . [0165] Meanwhile, this embodiment mode shows an example of a multilayer printed board in which a power supply pin for supplying power to an element is provided near the central axis of the BC layer 6 to improve an impedance characteristic. Other structures and operations are identical to those in the first embodiment mode. Therefore, the same symbols are provided to the same constituent elements and their descriptions are omitted here. [0000] <Structure> [0166] FIG. 14 and FIG. 15 show an outside of the multilayer printed board according to the second embodiment mode of the present invention. FIG. 14 is a perspective view showing the multilayer printed board. FIG. 15 is a plan view showing the multilayer printed board in the case where it is viewed from a direction indicated by an arrow D in FIG. 14 . [0167] As shown in FIG. 14 , the multilayer printed board is a multilayer printed board which includes the printed boards (multiple layers including a signal layer) 2 - 1 , 2 - 2 , and 2 - 3 and the BC layers 6 and a position in which the LSI 1 is mounted is devised. Here, it is desirable that the LSI 1 be an element to or from which a signal driven at highest speed is inputted or outputted on the multilayer printed board. [0168] As shown in FIG. 14 , the number of signal layers is not particularly limited in the multilayer printed board. That is, the number of signal layers may be one or plural. [0169] In FIG. 14 , the multilayer printed board includes the two BC layers 6 . However, in the embodiment of the present invention, the number of BC layers 6 may be one. As in the first embodiment, the two or more BC layers 6 may be provided, the power supply layers 3 of the respective BC layers may be connected with each other through the power supply via, and the ground layers 5 may be connected with each other through the ground via. [0170] As shown in FIG. 15 , the feature of the multilayer printed board according to this embodiment mode is to locate power supply pins 17 of the LSI 1 substantially at the center of the BC layer 6 of the multilayer printed board. According to such location, the power supply vias connected with the power supply pins 17 can be formed near the central axis passing through the substantially center of the BC layer 6 . In the example shown in FIG. 15 , ground pins 18 are located adjacent to the power supply pins 17 . [0171] Note that in the multilayer print shown in FIG. 14 , the respective printed boards (multiple layers 2 - 1 , 2 - 2 , and 2 - 3 and the BC layers 6 ) have substantially the same size (rectangle of 50 mm square) in the plan view as viewed from the direction indicated by the arrow D in FIG. 14 . [0000] <Natural Resonance Frequency of Board> [0172] FIG. 16 is an explanatory view of a natural resonance frequency of a printed board. FIG. 16 shows a natural resonance frequency of a rectangular copper sheet to a high frequency signal. Here, the copper sheet is indicated by a rectangular sheet 9 of a size of a (meters)×b (meters). Assume that a dielectric having a dielectric constant er exists around the rectangular sheet 9 made of copper. At this time, it is experimentally known that the natural resonance frequency can be expressed by formula 1 . [0173] In the formula 1 , C 0 denotes the speed of light in a vacuum. In the formula 1 , m and n each denote an integer equal to or larger than 0 (at least one is equal to or larger than 1) and are determined according to a resonance mode. [0174] For example, when the dielectric constant er=3.12, a=0.05 (meters), and b=0.05 (meters), a first resonance frequency fc (in the case of m=1 and n=0) is calculated to be 1.69 GHz. [0175] This embodiment mode shows that the power supply pins 17 of the LSI 1 and the power supply vias 7 can be located near the center of the BC layer 6 to suppress such resonance. [0176] It is expected that the resonance occurs in the case where the ½-wavelength of a high frequency signal is substantially equal to, for example, the length “a” (in the case of m=1). In addition, it is expected that the resonance occurs in the case where the ½-wavelength of the high frequency signal is substantially equal to, for example, the length “b” (in the case of n=1). Note that there is a resonance mode which cannot be determined by the experimental formula 1 shown in FIG. 16 in an actual printed board. [0177] In the multilayer printed board, the power supply pins 17 of the LSI 1 and the power supply vias 7 are located at the central position of the BC layer 6 (on the central axis of a thin copper plate for forming the power supply layer 3 and the ground layer 5 (on an axial direction perpendicular to the thin copperplate)). According to such location, a distance between a signal generation position of the BC layer 6 (position of the power supply via connected with the power supply pin 17 on the BC layer 6 ) and each end portion of the BC layer 6 (both sides of the rectangular thin copper plate for forming the power supply layer 3 ) becomes shorter. Therefore, the distance between the signal generation position and each end portion of the BC layer 6 does not become equal to the ½-wavelength of the high frequency signal. Thus, the natural resonance in the BC layer 6 is suppressed. [0178] In an actual design, the power supply pins 17 of the LSI 1 and the power supply vias connected therewith cannot be located near the accurate central axis of the BC layer 6 in some case. In such a case, the degree of suppression to the natural resonance is changed according to a deviation from the accurate central position. As described in the following embodiment, a radiation electric field intensity caused by the resonance increases as the power supply via is located near to one of the end portions of the BC layer 6 . Note that an effect in which a radiation electric field strength is reduced by about 10 dB as compared with a worst value is obtained in a range of 20% of a distance off from the center, between the center of the BC layer 6 and the end portion of the rectangular thin copper plate. Embodiment 4: Result Obtained by Impedance Measurement [0179] FIG. 17 and FIG. 18 show Embodiment 4 of the present invention. A multilayer printed board is a square in which a flat size of each layer is 50 mm×50 mm. The multilayer printed board includes a single BC layer. The BC layer is composed of a power supply layer, a thin film dielectric, and a ground layer. A thickness of the thin film dielectric is 25 microns as in the first embodiment mode. Each of layers located above and below the BC layer has an insulator having a thickness of 40 microns. [0180] FIG. 17 shows a shape of the printed board 2 - 1 (or the BC layer 6 ) in the case where the multilayer printed board is viewed from the direction indicated by the arrow D in FIG. 14 . TH 3 indicates a through hole passing through the vicinity of the central position of the BC layer 6 . An axis which corresponds to the through hole and is perpendicular to a paper surface is referred to as the central axis of the BC layer 6 . [0181] Similarly, TH 1 indicates a through hole passing through the vicinity of a vertex of the rectangular BC layer 6 . Similarly, TH 2 indicates a through hole passing through the vicinity of the center of a square side composing the BC layer 6 . As described in the first embodiment mode, a power supply via is formed in each of the through holes. Each power supply via is connected with the power supply layer 3 . An outer diameter of the power supply via in this embodiment is 0.3 mm equal to that in the first embodiment mode. [0182] As shown in FIG. 17 , in this embodiment mode, the power supply pins of the LSI 1 are located at the positions of TH 1 to TH 3 and connected with the vias located at the respective positions to produce three kinds of multilayer printed boards. In each of the multilayer printed boards, the impedance between the power supply layer 3 and the ground layer 5 is measured. [0183] In the measurement, a black box is assumed between the power supply layer 3 and the ground layer 5 which compose the BC layer 6 . AS (scattering) parameter is obtained using a network analyzer. The impedance between the power supply layer 3 and the ground layer 5 is obtained from the value of the S parameter. Note that a matrix representation of the S parameter is called a S matrix. A procedure for obtaining the impedance of the black box from the S matrix is known. [0184] As shown in the abscissa of each of graphs G 1 to G 3 , a frequency is changed from the vicinity of 0 Hz to the vicinity of 10 GHz to measure the impedance. In the graphs G 1 to G 3 , peaks and valleys (for example 100 and 101 in G 1 ) each indicate a resonance point. [0185] As is apparent from G 3 shown in FIG. 17 , when the power supply pin 17 of the LSI 1 is located in TH 3 , peaks 100 to 103 present in G 1 disappear. This may be because a distance between the position of the TH 3 and an outer edge of the BC layer 6 (thin copper plate of the power supply layer 3 ) is shorter than the ½-wavelength of the high frequency wave. That is, although the high frequency wave is injected from the via formed at the position of the TH 3 to the BC layer 6 , the resonance caused thereby is suppressed. [0186] As is apparent from a result obtained by measurement in G 2 , the peaks 102 and 103 present in G 1 disappear. This may be because a distance between the position of the TH 2 and each of sides (sides 50 and 51 ) of the BC layer 6 (thin copper plate of the power supply layer 3 ) is shorter than the ½-wavelength of the high frequency wave at the resonance frequency. On the other hand, the peaks 100 and 101 present in G 1 do not disappear even in the result obtained by measurement in G 2 (they are present as peaks 100 A and 101 A). This may be because a distance between the position of the TH 2 and an opposite side (side 52 ) of the BC layer 6 (thin copper plate of the power supply layer 3 ) is close to the ½-wavelength of the high frequency wave at the resonance frequency. [0187] FIG. 18 shows the superposition of results of G 1 to G 3 obtained by measurement as shown in FIG. 17 . As shown in FIG. 18 , a resonance characteristic of the peak 100 A in the result G 2 becomes weaker than that of the peak 100 in the result G 1 . Note that each of frequencies of the peaks is substantially equal to a result obtained by calculation based on the formula 1 and is about 1690 MHz. In the result of G 3 , as indicated by reference 100 B, the peak in the vicinity of 1.69 GHz disappears. [0000] <Analytical Result of Current Distribution> [0188] FIGS. 19 to 24 show analytical results of a high frequency current distribution in the vicinity of the resonance frequency in each of the cases where the power supply pin 17 of the LSI 1 is located in TH 1 to TH 3 . In this analysis, it is assumed to leak a high frequency signal from the power supply pin 17 and a current distribution in each of the cases where a high frequency voltage is supplied from the positions of TH 1 to TH 3 is obtained. [0189] FIG. 49 shows an analytical model of the multilayer printed board according to this embodiment mode. As shown in FIG. 49 , the analytical model includes a thin film dielectric 2 A, the power supply layer 3 , a thin film dielectric 2 B, the ground layer 5 , and a thin film dielectric 2 C. The thin film dielectrics 2 A, 2 B, and 2 C have 40 microns, 25 microns, and 40 microns in thickness, respectively. Each of the thin film dielectrics 2 A, 2 B, and 2 C has a dielectric constant Er of 3.12. [0190] In this model, a wave source (high frequency power supply) is set between the power supply layer 3 and the ground layer 5 . The wave source is connected with the power supply layer 3 and the ground layer 5 through the via. The wave source is originally necessarily set to the power supply via that connects the power supply pin of the LIS mounted on the multilayer printed board with the power supply layer. However, as in the first embodiment mode, the wave source is set to the above-mentioned position for simplification of the model. In order to fit the simplified model to a measured value, a parasitic inductor is set to the power supply via. [0191] As in the first embodiment mode, a high frequency power supply signal has a trapezoid waveform whose rise time and fall time each are 500 ps, period is 100 MHz, and amplitude is 3.3 volts. [0192] Even in the analysis, the electromagnetic analysis program based on the piecewise sinusoidal moment method is used as in the first embodiment mode. Hereinafter, FIG. 19 to FIG. 21 show current distributions at a frequency of 1600 MHz, each of which corresponds to the vicinity of the peak 100 shown in FIG. 18 . [0193] FIG. 19 shows an analytical result of a current distribution in a direction indicated by an arrow E in the case where the power supply pin 17 is located in TH 1 shown in FIG. 17 . In the analysis, the wave source is set just below TH 1 and between the power supply layer 3 and the ground layer 5 (see FIG. 49 ). As shown in FIG. 19 , a current in the direction indicated by the arrow E produces a distribution having a mountain shape with respect to the side 51 of the BC layer 6 . A peak of the mountain shape corresponds to a current density of about 0.1 A/m. [0194] FIG. 20 shows an analytical result of a current distribution in the direction indicated by the arrow E in the case where the power supply pin 17 (power supply via 7 ) is located in TH 2 shown in FIG. 17 . In the analysis, the wave source is set just below. TH 2 and between the power supply layer 3 and the ground layer 5 (see FIG. 49 ). As shown in FIG. 20 , even in this case, a current in the direction indicated by the arrow E produces a distribution having a mountain shape with respect to the side 51 of the BC layer 6 . A peak of the mountain shape corresponds to a current density of about 0.15 A/m. [0195] FIG. 21 shows an analytical result of a current distribution in the direction indicated by the arrow E in the case where the power supply pin 17 (power supply via 7 ) is located in TH 3 shown in FIG. 17 . In the analysis, the wave source is set just below TH 3 and between the power supply layer 3 and the ground layer 5 (see FIG. 49 ). As shown in FIG. 21 , in this case, a current in the direction indicated by the arrow E is locally produced in the vicinity of the position of the power supply pin 17 of the LSI 1 . A peak of the current at a narrowly limited area close to the position of the power supply pin 17 corresponds to about 0.75 A/m. [0196] Hereinafter, FIG. 22 to FIG. 24 show current distributions at a frequency of 2330 MHz, each of which corresponds to the vicinity of the peak 101 shown in FIG. 18 . FIG. 22 shows an analytical result of a current distribution in a direction indicated by an arrow F in the case where the power supply pin 17 is located in TH 1 shown in FIG. 17 . As shown in FIG. 22 , a current in the direction indicated by the arrow F produces a mountain-shaped distribution having a saddle portion. The reason why the saddle portion is formed may be that the resonance mode is different from that in the case of FIG. 19 . In FIG. 22 , a peak of the mountain shape corresponds to a current density of about 0.3 A/m. [0197] FIG. 23 shows an analytical result of a current distribution in the direction indicated by the arrow F in the case where the power supply pin 17 is located in TH 2 shown in FIG. 17 . As shown in FIG. 23 , in this case, a current in the direction indicated by the arrow F is locally produced in the vicinity of the position of the power supply pin 17 of the LSI 1 . A peak of the current at a narrowly limited area close to the position of the power supply pin 17 corresponds to about 0.75 A/m. This is because a distance between a voltage supply point and the side 50 or 51 in the direction indicated by the arrow F is not equal to an integral multiple of a half wavelength of the high frequency wave at the resonance frequency (2.333 GHz). [0198] FIG. 24 shows an analytical result of a current distribution in the direction indicated by the arrow F in the case where the power supply pin 17 is located in TH 3 shown in FIG. 17 . The analytical result shown in FIG. 24 is substantially identical to that in the case of FIG. 21 . [0000] <Analytical Result of Radiation Electric Field Strength> [0199] FIG. 25 to FIG. 35 show analytical results of a radiation electric field strength caused by an electromagnetic wave from the multilayer printed board. In the analysis, the electromagnetic wave emitted from the model of the multilayer printed board as shown in FIG. 49 is analyzed at each of positions shown in FIG. 50 to obtain a maximal value of the electric field strength among values got in the analyzed points. The reason why the maximal value of the electric field strength is obtained is to obtain an electric field strength at a position in which a directivity of a radiation pattern formed by the multilayer printed board becomes maximal. [0200] According to the analysis, when current distributions of the model of the multilayer printed board as shown in FIG. 49 are obtained, electric field strengths can be obtained by solving Maxwell equations with respect to the respective current distributions. This becomes, for example, the superposition of radiation electric fields caused by respective currents obtained on a mesh as shown in FIG. 25 . [0201] FIG. 50 shows observation points of the radiation electric field strength. As shown in FIG. 50 , a cylindrical coordinates system is used and the multilayer printed board is located at the center of the cylinder. At this time, the central axis (z-axis) of the cylinder is aligned with a normal line passing through the center of the multilayer printed board. Divisional lines parallel to the z-axis are set by which a cylindrical surface distanced from the central axis by a radius of 1.5 m is divided into 72 segments in a circumferential direction. [0202] Divisional lines in the circumferential direction are set by which the cylindrical surface is divided into 6 segments within an area of 3 m in a Z-direction. Positions of the divisional lines in the circumferential direction correspond to Z=1.5 m, 0.9 m, 0.3 m, −0.3 m. −0.9 m, and −1.5 m. In this case, the central position of the multilayer printed board in the Z-direction (position of Z 0 shown in FIG. 49 ) is set to Z=0 in the cylindrical coordinates. Intersections of the divisional lines parallel to the z-axis and the divisional lines in the circumferential direction are set to the observation points. When the electric filed strength is measured, an antenna for measuring vertical polarization and horizontal polarization may be set in the observation points. [0203] FIG. 25 shows a relationship between the central position of the BC layer 6 and the position of the power supply via 7 connected with the power supply pin 17 of the LSI 1 (position in which the wave source is projected when being projected to the BC layer 6 ). In FIG. 25 , the BC layer 6 is specified using references 6 A to 6 G based on the position of the power supply via 7 . [0204] The drawing of the BC layer 6 A shows the case where the power supply via 7 is located at a center 110 of the BC layer. In any cases ( 6 A to 6 G), assume that a flat surface of the BC layer is a square whose side length is 50 mm. [0205] The drawing of the BC layer 6 B shows the case where the power supply via 7 is shifted from the center 110 of the BC layer by 3.85 mm. In this case, according to expression using a relative amount in which positions of the four sides of the rectangle are set as 100%, the degree of shift of the power supply via 7 from the center 110 is 3.85/25=15.4%. In FIG. 25 , a shift direction is a direction from the center of the BC layer to the center of a side of a rectangular region. [0206] The drawing of the BC layer 6 C shows the case where the power supply via 7 is shifted from the center 110 of the BC layer by 7.7 mm. In this case, according to the expression using the relative amount in which the positions of the four sides of the rectangle are set as 100%, the degree of shift of the power supply via 7 from the center 110 is 7.7/25=30.8%. [0207] The drawing of the BC layer 6 D shows the case where the power supply via 7 is shifted from the center 110 of the BC layer by 11.6 mm. In this case, according to the expression using the relative amount in which the positions of the four sides of the rectangle are set as 100%, the degree of shift of the power supply via 7 from the center 110 is 11.6/25=46.4%. [0208] The drawing of the BC layer 6 E shows the case where the power supply via 7 is shifted from the center 110 of the BC layer by 15.4 mm. In this case, according to the expression using the relative amount in which the positions of the four sides of the rectangle are set as 100%, the degree of shift of the power supply via 7 from the center 110 is 15.4/25=61.6%. [0209] The drawing of the BC layer 6 F shows the case where the power supply via 7 is shifted from the center 110 of the BC layer by 19.3 mm. In this case, according to the expression using the relative amount in which the positions of the four sides of the rectangle are set as 100%, the degree of shift of the power supply via 7 from the center 110 is 19.3/25=77.2%. [0210] The drawing of the BC layer 6 G shows the case where the power supply via 7 is shifted from the center 110 of the BC layer by 23.1 mm. In this case, according to the expression using the relative amount in which the positions of the four sides of the rectangle are set as 100%, the degree of shift of the power supply via 7 from the center 110 is 23.1/25=92.4%. [0211] FIG. 26 and FIG. 27 show analytical results of the radiation electric field strength in the cases where the position of the power supply via 7 is changed (wave source shown in FIG. 49 ). [0212] FIG. 26 is a plot showing a radiation electric field strength (horizontal polarization component) according to a positional relationship between the central position 110 and the power supply via 7 in the BC layer 6 based on a frequency. In FIG. 26 , the positional relationship between the central position 110 and the power supply via 7 of the LSI 1 is expressed at a ratio thereof to a size of the entire BC layer. Here, when the power supply via 7 is on a side of the rectangle formed by the BC layer 6 (conductor composing the power supply layer and the ground layer), the ratio is 100%. [0213] The ordinate in FIG. 26 indicates the radiation electric field strength of horizontal polarization in the case where a high frequency signal in each positional relationship is supplied to the power supply via 7 (wave source shown in FIG. 49 ) and its unit is dBμV/m. As described above, a signal from a high frequency power source set as the wave source has a trapezoid waveform whose rise time and fall time each are 500 ps, period is 100 MHz, and amplitude is 3.3 volts. [0214] As shown in FIG. 26 , in any positional relationship, the radiation electric field strength becomes maximal at a frequency of the vicinity of the 1690 MHz. Therefore, this is identical to the results ( FIG. 17 and FIG. 18 ) or the analytical results ( FIG. 19 to FIG. 24 ) as described earlier. [0215] The horizontal polarization is very weak in the case where the power supply via 7 (power supply pin 17 of the LSI 1 ) is located at the center 110 of the BC layer. [0216] On the other hand, the radiation electric field strength increases as the power supply via 7 (power supply pin 17 of the LSI 1 ) is shifted to a peripheral portion. Note that the electric field strength in the case of separation of 20% or less is reduced by substantially 10 dB or more as compared with the case of separation of 90% or more between the central position 110 and the peripheral portion. [0217] FIG. 27 shows an analytical result of a vertical polarization component under the same condition as that in the case of FIG. 26 . As is apparent from FIG. 27 , even in the vertical polarization, the radiation electric field strength becomes maximal at a frequency of the vicinity of the 1690 MHz. [0218] Even when the power supply via 7 (power supply pin 17 of the LSI 1 ) is located at the center 110 of the BC layer, the vertical polarization becomes larger than the horizontal polarization. [0219] Even in the case of the vertical polarization, the radiation electric field strength further increases as a projection position 17 A of the power supply pin 17 of the LSI 1 is shifted to a peripheral portion. Note that the electric field strength in the case of separation of 20% or less is also reduced by substantially 10 dB or more as compared with the case of separation of 90% or more between the central position 110 and the peripheral portion. [0220] FIG. 28 shows respective states ( 6 H to 6 L) of the BC layer 6 in the cases where the power supply via 7 (power supply pin 17 of the LSI 1 ) is shifted from the central position in the vertex direction of the rectangle formed by the BC layer. [0221] FIG. 29 shows a result obtained by analysis of the horizontal polarization of the radiation electric field strength in the case where the positional relationship is changed as shown in FIG. 28 . Even in the case of the shift in the vertex direction as shown in FIG. 28 , the same result as that shown in FIG. 26 is exhibited with respect to the horizontal polarization. Note that a position of 100% in FIG. 29 corresponds to a vertex position (each of four corner ends) of the rectangle formed by the BC layer as shown in FIG. 28 . [0222] FIG. 30 shows a result obtained by analysis of the vertical polarization of a radiation electric field strength in the case where the positional relationship is changed as shown in FIG. 28 . Even in the case of the shift in the vertex direction as shown in FIG. 28 , the same result as that shown in FIG. 27 is exhibited with respect to the vertical polarization. [0223] FIGS. 31 to 35 show results obtained by the same analysis as that shown in FIG. 25 to FIG. 30 with respect to the multilayer board including the BC layer 6 having a rectangular shape of 25 mm square. FIG. 31 shows a position of the power supply via 7 connected with the power supply pin 17 of the LSI 1 (wave source is set between the power supply layer and the ground layer). FIG. 32 shows an analytical result of horizontal polarization in the case where the power supply via 7 is shifted from the center 110 of the BC layer to the center of a side of the rectangle. FIG. 33 shows an analytical result of vertical polarization in such a case. [0224] FIG. 34 shows an analytical result of horizontal polarization in the case where the power supply via 7 (and the wave source located just thereunder) is shifted from the center 110 of the BC layer in the vertex direction of the rectangle. FIG. 35 shows an analytical result of vertical polarization in such a case. [0225] According to the formula 1 shown in FIG. 16 , the natural resonance frequency of the square of 25 mm is twice that of a square of 50 mm and thus becomes 3.38 GHz. As shown in FIGS. 32 to 35 , the electric field strength becomes maximal in the vicinity of the natural resonance frequency in any cases. In any cases, the radiation electric field strength increases as the power supply via 7 is shifted to the peripheral portion. Note that the electric field strength in the case of separation of 20% or less is also reduced by substantially 10 dB or more as compared with the case of separation of 90% or more between the central position 110 and the peripheral portion. [0226] As described above, when the power supply pin 17 of the LSI 1 (element having a highest operating frequency is desirable) on the signal layer in the multilayer printed board is located such that a projection position onto the BC layer 6 is close to the center of the BC layer 6 , the natural resonance can be reduced. For example, when the power supply pin 17 of the LSI 1 on the signal layer is vertically connected to each board through the power supply via 7 , it may be desirable that the power supply via 7 is provided close to the central portion of the BC layer. [0227] Assume that a size of the entire board (end position of the rectangle formed from the BC layer) is 100%. At a position which is within an area of 20% from the central position 110 , the electric field strength can be reduced by 10 dB or more as compared with the case where the power supply via 7 is located in the board end portion of the BC layer 6 . [0000] <Modified Example> [0228] In the first embodiment mode and the second embodiment mode, the BC layer 6 and another layer such as the signal layer 2 - 1 are formed in substantially the same shape. However, the embodiment of the present invention is not limited to such a shape. [0229] For example, as shown in FIG. 48 , the size of the BC layer 6 may be narrowed as compared with another printed board. FIG. 48 shows the modified example of the multilayer printed board according to this embodiment mode as viewed from the upper side (for example, in the direction indicated by the arrow D in FIG. 14 ). [0230] That is, the metallic coating portion 3 A of the power supply layer 3 may be formed in a portion of the board composing the power supply layer 3 and the metallic coating portion 5 A of the ground layer 5 may be formed in a portion of the board composing the ground layer 5 . This corresponds to the case where the BC layer 6 is provided only in the vicinity of the specific LSI 1 in the multilayer printed board. Therefore, even when a portion of the multilayer printed board composes the BC layer 6 , the present invention can be embodied. [0231] That is, the power supply via 7 of the LSI 1 may be located close to the center of the BC layer 6 with respect to the partial BC layer 6 . Third Embodiment Mode [0232] Hereinafter a multilayer printed board according to a third embodiment mode of the present invention will be described with reference to FIG. 36 to FIG. 47 . [0000] <Structure> [0233] FIG. 36 is a perspective view showing the multilayer printed board according to the third embodiment mode of the present invention. [0234] As shown in FIG. 36 , the BC layer in the multilayer printed board according to this embodiment mode becomes a circle as compared with that shown in the first embodiment mode ( FIG. 1 and the like) or the second embodiment mode ( FIG. 14 ) (This is referred to as the circular BC layer 16 ). That is, a metallic thin film (copper thin film) composing each of a power supply layer 13 and a ground layer 15 becomes a circle. [0235] On the other hand, other constituent elements of the multilayer printed board according to this embodiment mode are identical to those in the case of the first embodiment mode or the second embodiment mode. Therefore, the same references are provided for the same constituent elements and thus the descriptions are omitted here. [0236] In FIG. 36 , the thin film dielectric 4 has the same shape as that shown in the first embodiment mode ( FIG. 1 and the like) or the second embodiment mode ( FIG. 12 ). Instead of such a shape, the thin film dielectric 4 may be formed in the same circular shape as that of the power supply layer 13 or the ground layer 15 . [0237] FIG. 37 is a plan view as viewed from a direction indicated by an arrow G in FIG. 36 . As shown in FIG. 37 , in the multilayer printed board according to this embodiment mode, the power supply pin 17 of the LSI 1 is located to the position where the central axis of the BC layer 16 (power supply layer 13 and ground layer 15 ) passes through. [0238] For example, the power supply via may be formed perpendicular to the board surface at the position of the power supply pin 17 so that the power supply via passes through the central axis of the BC layer 16 . In FIG. 37 , the ground pin 18 of the LSI 1 is located close to the power supply pin 17 . [0239] According to such a structure, a distance between the power supply via and each of the peripheral portions of the BC layer 16 (peripheral portion of the copper thin film composing the power supply layer 13 and the peripheral portion of the copper thin film composing the ground layer 15 ) can be adjusted to an equal distance on the BC layer 16 . FIG. 38 shows comparison between the BC layer 16 and the BC layer 6 in the first embodiment mode or the second embodiment mode. [0240] In the second embodiment mode, the BC layer is formed in the rectangular shape of 50 mm (or 25 mm) square. On the other hand, in this embodiment mode, a copper thin film having a diameter of 50 mm is used for the power supply layer 13 and the ground layer 15 in order to form the circular BC layer 16 . [0241] FIG. 39 shows analytical results of impedance in the case where the power supply via is located close to the central axis of the BC layer which is the rectangle of 50 mm square as used in the second embodiment mode and in the case where the power supply via is located close to the central axis of the circular BC layer 16 having the diameter of 50 mm. The analytical procedure and the analytical condition are identical to those in the second embodiment mode. That is, the wave source is set between the power supply layer and the ground layer. [0242] A graph 120 shows a frequency characteristic of an impedance between the power supply layer 3 and the ground layer 5 in the case where the power supply via (and the wave source located just thereunder) is located close to the central axis of the BC layer which is the rectangle of 50 mm square as used in the second embodiment mode. As described in the second embodiment mode, when the power supply via is located close to the center of the rectangular BC layer 6 (power supply pin 17 of the LSI 1 is located close to the central axis of the BC layer 6 on the signal layer), a natural resonance mode can be suppressed and a peak impedance value at the time of natural resonance can be reduced. [0243] When the circular BC layer 16 in this embodiment mode is employed and the power supply via is located close to the central axis thereof, as shown in the graph 121 , the natural resonance mode can be further suppressed as compared with the case of the rectangle. For example, in the case of the graph 121 of FIG. 39 , only two resonance points are present in the vicinities of 4000 MHz and 7100 MHz. [0244] It may be the result of reduction of combinations of resonance modes, which is brought by a distance up to the peripheral portion of the circular BC layer 16 becoming substantially equal as viewed from the center of the circular BC layer 16 . [0000] <Modified Example> [0245] The third embodiment mode shows that, when the circular BC layer 16 is employed and the power supply via is located close to the central axis of the circular BC layer 16 , it is possible to suppress the resonance mode. That is, the power supply pin 17 of an IC having a highest operating frequency is located close to the axis passing through the center of the circular BC layer 16 to reduce the natural resonance mode of the BC layer. [0246] However, the embodiment of the present invention is not limited to such a structure. For example, as shown in FIG. 40 , the BC layer may be formed in a flat shape of a regular polygon other than a square, such as a regular octagon, a regular hexadecagon, or a regular triacontakaidigon. [0247] FIG. 41 is a graph obtained by plotting a frequency characteristic of an impedance between the power supply layer and the ground layer in the BC layer having the flat shape of the square, the regular octagon, the regular hexadecagon, or the regular triacontakaidigon. [0248] In FIG. 41 , the rectangle indicates the case where the BC layer is a rectangle of 50 mm square. The octagon, the hexadecagon, or the triacontakaidigon indicates the case where the BC layer is a regular polygon. In such a case, a length of a diagonal line of each of the regular octagon, the regular hexadecagon, and the regular triacontakaidigon is set to 50 mm. [0249] As is apparent from FIG. 41 , the resonance in a low frequency domain is suppressed as the polygon is changed from the rectangle to the regular octagon, the regular hexadecagon, or the regular triacontakaidigon (respectively indicated by the octagon, the hexadecagon, or the triacontakaidigon in FIG. 41 ), so that the resonance position is present on the high frequency side. In FIG. 41 , the reason why the resonance position in the regular hexadecagon is present on the high frequency domain side than that in the regular triacontakaidigon may be an analytical error caused by modeling. [0250] FIGS. 42 and 43 show analytical results of current densities in the rectangular BC layer in the vicinities of the resonance points. FIGS. 44 and 45 show analytical results of current densities in the regular octagonal BC layer and the regular triacontakaidigonal BC layer at the time of resonance. In each of those results, the same high frequency voltage as that in the second embodiment mode is supplied to obtain a current density distribution. [0251] FIG. 42 shows a current distribution in the rectangular BC layer, which is caused by a high frequency current of 3.29 GHz. This is a current distribution in the vicinity of a resonance point present on a low frequency domain side in the rectangle shown in FIG. 41 (left side in FIG. 41 ). FIG. 43 shows a current distribution in the rectangular BC layer, which is caused by a high frequency current of 4.65 GHz. This is a current distribution in the vicinity of a resonance point present on a high frequency domain side in the rectangle shown in FIG. 41 (right side in FIG. 41 ). [0252] FIG. 44 shows a current distribution in the octagonal BC layer, which is caused by a high frequency current of 4.65 GHz. [0253] FIG. 45 shows a current distribution in the triacontakaidigonal BC layer, which is caused by the high frequency current of 4.65 GHz. [0254] As is apparent from FIGS. 42 to 45 , the current densities in the regular octagonal BC layer and the regular triacontakaidigonal BC layer reduce as compared with the rectangular BC layer. Note that the case of the regular hexadecagonal BC layer is similar to the case of the regular triacontakaidigonal BC layer (not shown here). [0255] FIG. 46 shows analytical results of radiation electric field strengths in the rectangular BC layer, the regular octagonal BC layer, the regular hexadecagonal BC layer, and the regular triacontakaidigonal BC layer at the time of resonance. The analytical condition and the measurement condition are identical to those in the second embodiment mode ( FIGS. 26, 27 , 29 , and 30 ). [0256] As shown in FIG. 46 , in the case of the rectangular BC layer, the radiation electric field strength becomes stronger in the vicinities of resonance points (such as the vicinities of 3300 MHz and 4800 MHz). On the other hand, the radiation electric field strengths in the regular octagonal BC layer, the regular hexadecagonal BC layer, and the regular triacontakaidigonal BC layer can be suppressed as compared with that in the rectangular BC layer. [0257] When the above-mentioned results are generalized, the flat shape of the BC layer is made such that a ratio Lmax/Lmin between maximal values Lmax and minimal values Lmin of a distance between the center of the BC layer and the peripheral portion of the BC layer becomes 1 to 1.41. Therefore, the resonance mode can be reduced to reduce the radiation electric field strength. For example, a conductor thin film composing the power supply layer and the ground layer (or at least one of those) may be formed such that the ratio Lmax/Lmin between the maximal values Lmax and minimal values Lmin of a distance between the center of the conductor thin film and the peripheral portion thereof becomes 1 to 1.41. [0258] For example, in the case of the square, the ratio between maximal and minimal values of a distance between the center and the peripheral portion is 1.41421356. In the case of circle, the ratio between maximal and minimal values of a distance between the center and the peripheral portion is 1. Fourth Embodiment Mode [0259] Hereinafter, the electronic apparatus 100 according to a fourth embodiment mode of the present invention will be described with reference to the drawing of FIG. 47 . The electronic apparatus 100 is, for example, a communication apparatus such as a router or a packet switching device or an information processing apparatus such as a computer main body. The feature of the electronic apparatus 100 is to include any one of the multilayer boards (multilayer board 101 in FIG. 47 ) as described in the first embodiment mode to the third embodiment mode in its case and mount the above-mentioned element thereon. [0260] Therefore, when the multilayer board 101 is constructed to connect between the plurality of BC layers 6 as described in the first embodiment mode, the impedance between the power supply layer 3 and the ground layer 5 in a low frequency domain (for example, up to the first resonance point) can be reduced. In such a case, when the plurality of power supply vias 7 or the plurality of ground vias 8 are provided, the resonance frequency can be shifted to the high frequency domain, with result that it is possible to widen the operating frequency band. [0261] When the power supply pin of a high-speed (for example, the operating frequency is 1 GHz or more) element is located close to the central axis of the BC layer in the multilayer board 101 as described in the second embodiment mode, the resonance mode can be reduced to reduce the radiation electric field strength. [0262] In the multilayer board 101 , as described in the third embodiment mode, the BC layer is formed in a shape of regular polygon having sides whose number is equal to or larger than five and the power supply pin of a highest-speed element is located close to the central axis of the BC layer. Therefore, the resonance mode can be further reduced to reduce the radiation electric field strength. [0263] Thus, when the multilayer printed board including any of the BC layers 6 described in the first embodiment mode to the third embodiment mode is introduced into the electronic apparatus, unnecessary resonance can be prevented to ensure stable operation. In addition, it is possible to increase the degree of freedom for designing the stable electronic apparatus. INDUSTRIAL APPLICABILITY [0264] The present invention can be used for an industry in which a printed board is manufactured and an industry in which an electronic apparatus including the printed board is manufactured. [0000] <<Others>> [0265] The disclosures of international application PCT/JP2003/001010, filed on Jan. 31, 2003 including the specification, drawings and abstract are incorporated herein by reference.

A multilayer printed board comprising a plurality of capacitive coupling layers ( 6 ) each consisting of a dielectric layer ( 4 ) and a power supply layer ( 3 ) and a ground layer ( 5 ) facing each other while sandwiching the dielectric layer ( 4 ), first vias ( 7 ) connecting between the power supply layers ( 3 ) included in the plurality of capacitive coupling layers ( 6 ), and second vias ( 8 ) connecting between the ground layers ( 5 ) included in the plurality of capacitive coupling layers ( 6 ).

RELATED APPLICATION DATA [0001] This application is a continuation of and claims priority to U.S. patent application Ser. No. 10/537,968 filed on Jun. 9, 2005, which claims priority to and is the U.S. national stage of PCT/US03/39067 filed on Dec. 9, 2003, which is based on and claims the benefit of U.S. Provisional Patent Application No. 60/432,219 filed on Dec. 9, 2002, all of the foregoing of which are incorporated herein in their entirety by this reference. INTRODUCTION [0002] Financial assistance for this invention was provided by the United States Government, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Department of Health and Human Services, Outstanding Investigator Grant CA44344-03-12 and CA90441-01; the Arizona Disease Control Research Commission; and private contributions. Thus, the United States Government has certain rights in this invention. FIELD OF THE INVENTION [0003] This invention relates to a novel compounds, and methods for synthesizing same, which show promising utility in the treatment of cancer. The compound described herein has been denominated narcistatin. Further described herein are numerous derivatives of narcistatin. BACKGROUND OF THE INVENTION [0004] Over 30 species representing 11 genera (among 85 total) of the plant family Amaryllidaceae have been employed in traditional treatments for human cancer. Such applications of certain Narcissus species were recorded as early as 200 B.C. (Pettit, G. R. et al., J. Nat. Prod. 1995, 58, 756-759; Pettit, G. R., et al., J. Nat. Prod., 1995, 58, 37-43.) The biologically active constituents of Amaryllidaceae species have been under investigation from at least 1877 following Gerrard's report on a component of Narcissus pseudonarcissus designated narcissia. (Gerrard, A. W., Pharm. J., 1877, 8, 214; Cook, J. W., In The Alkaloids , Manske, R. H. F.; Holmes, H. L., Ed.; Academic Press: New York, 1952; pp. 331.) Presently, some 48 alkaloids and carbostyrils bearing a variety of carbon skeletons have been isolated from Narcissus species. (Weniger, B., et al., Planta Med., 1995, 61, 77-79.) Of these, the isocarbostyrils narciclasine (1) and pancratistatin (2) have been found to display the most promising in vivo antineoplastic activities and a selection of other amaryllidaceae alkaloids have been shown to provide cancer cell growth inhibitory activity. (Pettit, G. R., et al., J. Nat. Prod., 1995, 58, 756-759; Pettit, G. R., et al., J. Nat. Prod., 1995, 58, 37-43; Pettit, G. R., et al., J. Org. Chem., 2001, 66, 2583-2587; Rigby, J. H., et al., J. Amer. Chem. Soc., 2000, 122, 6624-6628; Suffness, M., et al., In The Alkaloids, Drossi, A., Ed., Academic Press: New York, 1985; pp. 205-207; Youssef, D. T. A., et al., Pharmazie 2001, 56, 818-822.) [0005] Pancratistatin (2), which we first discovered in Pancratium littorale (reidentified as Hymenocallis littoralis ) and later in Narcissus species, has been undergoing extended preclinical development. (Pettit, G. R., et al., J. Org. Chem., 2001, 66, 2583-2587; Rigby, J. H., et al., J. Amer. Chem. Soc. 2000, 122, 6624-6628; Pettit, G. R., et al., J. Nat. Prod., 1995, 58, 756-759; Pettit, G. R., et al., J. Nat. Prod., 1995, 58, 37-43.) That very important initiative was greatly assisted by conversion of the sparingly soluble isocarbostyril to a 7-O-phosphate salt. (Pettit, G. R., et al., Anti - Cancer Drug Design 2000, 15, 389-395; Pettit, G. R., et al., Anti - Cancer Drug Design 1995, 10, 243-250.) The antimitotic activity of narciclasine (1) has been known for over 35 years. Subsequently, it was shown in U.S. National Cancer Institute research to be active against in vivo growth of the M5076 sarcoma and P388 lymphocytic leukemia. In addition, it was found to inhibit protein synthesis in Erlich asciter cancer cells. (Suffness, M., et al., The Alkaloids, Drossi, A., Ed., Academic Press: New York, 1985; pp. 205-207.) However, as with the closely related pancratistatin (2), the low solubility properties of narciclasine has contributed to the delay in its preclinical development. Most of the inventors' early investigation involving this potentially useful isocarbostyril have targeted its use as a starting point for a practical synthesis of pancratistatin (2) and for SAR purposes. (Pettit, G. R., et al., J. Org. Chem. 2001, 66, 2583-2587; Rigby, J. H., et al., Amer. Chem. Soc. 2000, 122, 6624-6628; Pettit, G. R., et al., J - C. Heterocycles 2002, 56, 139-155.) Disclosed herein a very convenient transformation of narciclasine (1) to water soluble cyclic phosphate prodrugs (3). SUMMARY OF THE INVENTION [0006] Disclosed herein are several derivatives of narciclasine, and methods for the synthesis of these derivatives. The compounds of the invention have the following structure: [0000] Compound 3a: Z = pyridinium Compound 3b: Z = H + Compound 3c: Z = Li + Compound 3d: Z = Na + Compound 3e: Z = K + Compound 3f: Z = Cs + Compound 3g: Z = Mg 2+ Compound 3h: Z = Ca 2+ Compound 3i: Z = Zn 2+ Compound 3j: Z = Mn 2+ Compound 3k, Z = quinidine Compound 3l: Z = quinine Compound 3m: Z = imidazole Compound 3n: Z = morpholine Compound 3o: Z = piperazine [0007] Narcistatin (3b) and fifteen salt derivatives were evaluated against a panel of human cancer cell lines and the range (0.1-0.01) of GI 50 values in μg/ml was found to parallel that shown by the parent narciclasine, and thus indicates that the compounds of the present invention show promise in the treatment of cancer in humans and animals. The water-soluble cyclic phosphate prodrugs disclosed herein will allow the potentially useful Narcissus anticancer component narciclasine to be utilized in cancer-fighting pharmaceuticals. [0008] Also disclosed herein is a method for the efficient synthetic conversion of the sparingly soluble anticancer compound isocarbostyril narciclasine (1), a component of various Narcissus species, to a more soluble cyclic-phosphate designated narcistatin (3b). The reaction between narciclasine, tetrabutylammonium dihydrogen phosphate, dicyclohexylcarbodiimide, and p-toluenesulfonic acid in pyridine afforded pyridinium narcistatin (3a) in reasonable yields. Preparation of sodium narcistatin (3d) was achieved by two methods. Procedure A involved the transformation of narcistatin (3a) into the water soluble prodrug (3d) and other salt derivatives by cation exchange chromatography. Procedure B allowed sodium narcistatin (3d) to be obtained in high yield, following cation exchange chromatography, from the reaction between narciclasine, tetrabutylammonium dihydrogen phosphate and dicyclohexylcarbodiimide in pyridine. DESCRIPTION OF THE DRAWINGS [0009] FIG. 1 illustrates the x-ray structure of pyridinium narcistatin (3a). [0010] FIG. 2 illustrates the x-ray cell contents of pyridinium narcistatin hydrate (3a). [0011] FIG. 3 illustrates the chemical structure of the narcistatin cyclic phosphate compounds of the invention. DETAILED DESCRIPTION OF THE INVENTION [0012] Early experience by one of the inventors in nucleotide chemistry involving phosphate esters and cellular phosphatases combined with recent successes in synthesis of phosphate prodrugs made such an approach most attractive for obtaining a water soluble narciclasine prodrug. (Pettit, G. R. Synthetic Nucleotides, Van Nostrand Reinhold Co: New York, 1972; Pettit, G. R., et al., Anti-Cancer Drug Design 2000, 15, 389-395; Pettit, G. R., et al., Anti-Cancer Drug Design 1995, 10, 243-250; Pettit, G. R., et al., Anti-Cancer Drug Design 2000, 15, 397-403; Saulnier, M. G., et al., Med. Chem. Lett. 1994, 4, 2567-2572; Ueda, Y., et al., Med. Chem. Lett. 1995, 5, 247-252.) However, a selection of the more obvious methods such as POCl 3 , or 2-cyanoethylphosphate with dicyclohexylcarbodiimide (DCCI), and various unprotected or protected (e.g. narciclasine 3,4-acetonide) strategies involving narciclasine (1) led to unpromising mixtures. (Pettit, G. R., et al., Anti-Cancer Drug Design 2000, 15, 389-395; Pettit, G. R., et al., Anti-Cancer Drug Design 1995, 10, 243-250; Taktakishvili, M., et al., Tetrahedron Lett. 2000, 41, 7173-7176; Tener, G. M., J. Amer. Chem. Soc. 1961, 83, 159-168; Scheit, K. H., Nucleotide Analogs, Synthesis and Biological Function; Wiley-Interscience: New York, 1972; Khorana, H. G., et al., J. Chem. Soc. 1953, 2257-2260; Khorana, H. G. J. Amer. Chem. Soc. 1954, 76, 3517-3527; Dekker, C. A., et al., J. Amer. Chem. Soc. 1954, 76, 3522-3527; Tener, G. M.; Khorana, H. G., J. Amer. Chem. Soc. 1955, 77, 5348.) Eventually, the inventors examined use of the readily soluble tetrabutylammonium dihydrogen phosphate in pyridine as the phosphate source. Initially, the phosphate failed to couple with narciclasine in the presence of DCCI until three equivalents of p-toluenesulfonic acid was employed to promote condensation, at which point precipitation of dicyclohexylurea (DCU) began. When the reaction mixture was heated to 80° C., the pyridinium salt of narciclasine-3,4-cyclic phosphate 3a (herein designated pyridinium narcistatin), precipitated. Following collection of precipitated DCU and the narcistatin pyridinium salt, the solids were titrated with water to dissolve the cyclic phosphate (3a). Concentration of the water fraction afforded the pyridinium salt in 40% yield. The mother liquor was concentrated to a brown oil and added to a large volume of water; an immediate precipitate was observed. The solution was filtered and the filtrate was found to be primarily unreacted narciclasine with some DCU as impurity. The reaction did not go to completion even after prolonged stirring and addition of more reagents. [0013] Examination of the 1 H-NMR (DMSO-d 6 ) spectrum of the pyridinium salt 3a showed a multiplet corresponding to the signals for four protons at 4.42-4.31 ppm and a doublet of doublets corresponding to the signal for one proton at 4.15 ppm. Assuming four ring hydrogens resonating in this region, the signal for H-1 was assigned downfield at 6.5 ppm. Only one of the signals corresponded to a hydroxyl group. A D 2 O experiment resulted in a considerable change in the splitting pattern of the multiplet at 4.3 ppm and 8.60 ppm, suggesting loss of the OH signal and NH-5 signal, respectively. Other signals at 13.66 and 9.00 were also absent from the D 2 O treated spectrum due to deuterium exchange with OH-7 and pyridinium NH. The 31 P-NMR (DMSO-d 6 ) spectrum gave one signal at 20.3 ppm suggesting only one phosphorus atom, this together with the 1 H NMR data suggested the formation of the cyclic phosphate. However, despite extensive 2D NMR experiments, the position of the phosphate could not be established unambiguously. Consequently, narciclasine pyridinium salt (3a) was recrystallized from pyridine-water and examined by X-ray crystallography to establish the 3,4-cyclic phosphate structure. The resulting structure of 3a is depicted in FIG. 1 . In addition to two pyridinium cations and two cyclic phosphate anions, the unit cell was found to contain three molecules of water solvate, as shown in FIG. 2 . [0014] In order to extend the narcistatin cation series, phosphoric acid 3b was prepared by dissolving the pyridinium narcistatin in water and passing it through a column containing Dowex 50W X8 200 cation exchange resin (hydrogen form). A solution of the pyridinium narcistatin in water was also used to prepare the lithium (3c), sodium (3d) (procedure A), potassium (3e) and cesium (3f) salts of narcistatin by passage through a Dowex 50W X2 column bearing the respective cations. The magnesium (3g), calcium (3h), zinc (3i), and manganese (3j) salts were obtained by suspending phosphoric acid 3b in methanol-water (3:2) and adding 0.5 equivalent of the respective metal acetate in water. The resulting opaque solution was stirred for several days as the salt precipitated from solution. These dication salts proved to be only sparingly soluble in water. A selection of ammonium salts were prepared by allowing phosphoric acid 3b to react with the respective amine (1.2 equiv) at room temperature. The reaction mixture was concentrated and product precipitated to give ammonium salts 3k-o. Procedure B for the preparation of sodium narcistatin 3d is as follows. The reaction between narciclasine, tetrabutylammonium dihydrogen phosphate and DCCI in pyridine was carried out at 80° C. without the addition of the para-toluene sulfonic acid. The reaction was monitored by 1 H NMR and found to go to completion in four days with addition of more reagents at 24 hours. Isolation followed by cation exchange chromatography gave sodium narcistatin in high yield (88%). [0015] Narciclasine cyclic phosphate prodrugs 3a-o were evaluated against a minipanel of human cancer cell lines and the murine P388 lymphocytic leukemia. Results of the cancer cell line evaluation of narcistatins 3a-o appears in Table 1. The GI 50 0.1-0.02 μg/ml strong activity range parallels that already reported for the parent, narciclasine (1). (Pettit, G. R.; Melody, N.; Herald, D. L. J. Org. Chem. 2001, 66, 2583-2587.) [0016] Experimental Section. [0017] Narciclasine (1) was isolated form Hymenocallis littoralis (Jacq.) Salisb, (Amaryllidaceae) grown by our group in Tempe, Ariz. (Pettit, G. R., et al., J. Nat. Prod. 1995, 58, 756-759; Pettit, G. R., et al., J. Nat. Prod. 1995, 58, 37-43.) Reagents were purchased from Aldrich Chemical unless otherwise noted and used as received. Solvents were distilled prior to use and pyridine preceding distillation was dried over potassium hydroxide pellets. Dowex 50X8-200 and Dowex 50WX2 cation exchange resins (H + form) were washed with methanol, 1 N hydrochloric acid and deionized water. The cation forms of the resin were obtained by washing with a 1 N solution of the appropriate base followed by deionized water. DEAE SEPHADEX A-25 weak anion exchange resin (acetate form) was purchased from the Sigma-Aldrich Company and was washed with 1 N triethylammonium bicarbonate (TEAB) solution and then equilibrated with 10 mN TEAB buffer solution. [0018] Melting points were determined on a Fisher-Johns melting point apparatus and are uncorrected. Thin layer chromatography was performed on Analtech silica gel GHLF plates, the narciclasine containing derivatives were visible as green-blue fluorescent spots under long wave ultraviolet light, and were rendered permanent by staining with iodine vapor. Phosphorous containing compounds were detected using the modified Jungnickel's reagent (perchloric acid-malachite green-sodium molybdate) developed by Vaskovsky and Latshev. (Khorana, H. G., et al., A. R. J. Chem. Soc. 1953, 2257-2260; Khorana, H. G., J. Amer. Chem. Soc. 1954, 76, 3517-3527; Dekker, C. A., et al., H. G. J. Amer. Chem. Soc. 1954, 76, 3522-3527; Tener, G. M., et al., J. Amer. Chem. Soc. 1955, 77, 5348.) Optical rotation values were recorded using a Perkin Elmer 241 polarimeter. High resolution FAB spectra were obtained using a JEOL LCMate magnetic sector instrument in either the FAB mode, with a glycerol matrix, or by APCI with a polyethylene glycol reference. All 1 H NMR spectra were obtained using a Varian Gemini 300 MHz instrument unless otherwise noted. The 13 C, 1 H— 1 H COSY, 1 H— 13 C HMBC, 1 H— 13 C HMQC, and 31 P-NMR experiments were conducted employing a Varian Unity 500 MHz instrument. [0019] Pyridinium Narcistatin (3a) [0020] Narciclasine (1) (1.0 g, 3.4 mmol) was added to pyridine (50 ml) and the solution was heated to 80° C. Next, tetrabutylammonium-dihydrogen phosphate (5.13 g, 15.11 mmol, 4.4 equiv), dicyclohexylcarbodiimide (5.0, 24.5 mmol, 7.0 equiv) and p-toluenesulfonic acid (3.0 g, 15.8 mmol, 4.63 equiv, added slowly) were added. After 2 g of the sulfonic acid was added, a precipitate began to separate. The reaction mixture was stirred under argon at 80° C. for 2.5 hours. The precipitate was collected and washed with methanol to remove pyridine. The precipitated cyclic phosphate (3a) was separated from the DCU by washing with water (200 ml). The aqueous filtrate was concentrated to an off-white solid and dried (vacuum) overnight to yield 0.59 g, 40.4%. The mother liquor was concentrated to a brown oil and water (750 ml) added. An immediate precipitate was observed, which was collected and dried to 0.75 g of white solid. The 1 H NMR (DMSO-d 6 ) showed this material to be recovered starting material with a small amount of DCU impurity. Recrystallization of phosphate 3a from pyridine-water gave crystals that were used for X-ray crystallography. [α] 26 D =−6.4° (c 0.44, DMSO); m.p. 275° C.; 1 H NMR (DMSO-d 6 , 500 MHz) δ 13.66 (s, 1H), 9.00 (s, 1H), 8.60 (m, 3H), 7.9 (t, J=7.5 Hz, 1H), 7.5 (m, 2H), 7.04 (s, 1H), 6.5 (s, 1H), 6.06 (d, J=3 Hz, 2H), 4.42-4.31 (m, 4H), 4.15 (dd, J=6.5 Hz, 1H); 13 C NMR (DMSO, 500 MHz) δ 167.7, 152.6, 148.6(2), 145.2, 137.4(2), 133.5, 128.5, 126.9, 125.3, 124.4, 104.3, 102.1, 94.3, 76.9, 76.7, 70.4, 53.9; 31 P(DMSO-d 6 , 200 MHz) 20.3 (s, 1P); found by HRAPC1 (negative ions) mass spec. 368.0179, calc. for C 14 H 11 O 9 NP 368.2164. Crystal Structure of Pyridinium Narcistatin (3a). [0021] X-Ray Crystal Structure Determination. Pyridinium narcistatin hydrate (3a): A thin plate (˜0.07×0.35×0.54 mm), grown from pyridine/water solution, was mounted on the tip of a glass fiber. Cell parameter measurements and data collection were performed at 123 K with a Bruker SMART 6000 diffractometer system using Cu Kα radiation. A sphere of reciprocal space was covered using the multirun technique. SMART for Windows NT v5.605; BrukerAXS Inc.: Madison, Wis., 2000. Thus, six sets of frames of data were collected with 0.396° steps in ω, and a last set of frames with 0.396° steps in φ, such that 91.7% coverage of all unique reflections to a resolution of 0.84 A was accomplished. [0022] Crystal Data: C 14 H 11 NO 9 P.C 5 H 6 N.1½H 2 O (hydrate), M r =475.34, triclinic, P1, a=7.4949(1), b=8.0371(1), c=16.9589(2) A, α=85.248(1), β=83.243(1), γ=79.383(1)°, V=994.60(2) A 3 , Z=2, ρ c =1.577 Mg/m 3 , μ(CuKα)=1.837 mm −1 , λ=1.54178 A, F(000)=494. [0023] A total of 7587 reflections was collected, of which 4733 reflections were independent reflections (R(int)=0.0273). Subsequent statistical analysis of the data set with the XPREP program indicated the spacegroup was P1. XPREP-The automatic space group determination program in the SHELXTL. (SHELXTL-NT Version 5.10; BrukerAXS Inc., Madison, Wis., 1997: an integrated suite of programs for the determination of crystal structures from diffraction data. This package includes, among others, XPREP (an automatic space group determination program), SHELXS (a structure solution program via Patterson or direct methods), and SHELXL (structure refinement software)). Final cell constants were determined from the set of the 4564 observed (>2σ(I)) reflections which were used in structure solution and refinement. An absorption correction was applied to the data with SADABS. (Blessing, R., Acta Crystallogr. 1995, A51, 33-38.) Structure determination and refinement was readily accomplished with the direct-methods program SHELXTL. (SHELXTL-NT Version 5.10; Bruker AXS Inc.: Madison, Wis., 1997.) An integrated suite of programs for the determination of crystal structures from diffraction data. This package includes, among others, XPREP (an automatic space group determination program), SHELXS (a structure solution program via Patterson or direct methods), and SHELXL (structure refinement software). All non-hydrogen atom coordinates were located in a routine run using default values for that program. The remaining H atom coordinates were calculated at optimum positions, except for water hydrogen atoms, which were located via difference maps. All non-hydrogen atoms were refined anisotropically in a full-matrix least-squares refinement procedure. The H atoms were included, their Uiso thermal parameters fixed at either 1.2 or 1.5 (depending on atom type) the value of the Uiso of the atom to which they were attached and forced to ride that atom. The final standard residual R 1 value for 3a was 0.0393 for observed data and 0.0403 for all data. The goodness-of-fit on F 2 was 1.053. The corresponding Sheldrick R values were wR 2 of 0.1074 and 0.1099, respectively. The final model used for pyridinium narcistatin 3a is shown in FIG. 1 . In addition to the parent molecules (i.e., two narcistatin anions and two pyridinium cations) in the unit cell, three molecules of water solvate were also present. One of these water molecules was disordered over two sites, each of which were given 0.5 site occupancies. A final difference Fourier map showed minimal residual electron density; the largest difference peak and hole being +0.350 and −0.255 e/Å 3 , respectively. Final bond distances and angles were all within expected and acceptable limits. [0024] Narcistatin (3b). [0025] A solution of pyridinium narcistatin (3a, 0.05 g) in water (2 ml) was obtained by heating (water bath) at 60° C. The solution was allowed to cool prior to passing through a column prepared from Dowex 50X8-200 cation exchange resin (hydrogen form). A suspension began to form in the column as the phosphoric acid (3b) formed. The column was eluted with water and phosphoric acid 3b eluted as a milky white suspension. The combined fractions containing phosphoric acid 3b were freeze dried to afford the product as a colorless solid, (36 mg, 86%); m.p. 175° C. (dec.); 1 H NMR (DMSO-d 6 , 300 MHz), δ 13.65 (s, 1H), 9.02 (s, 1H), 7.06 (s, 1H), 6.48 (s, 1H), 6.17 (d, J ab =10.2 Hz, 1H), 6.06 (m, 2H), 4.46-4.30 (m, 3H), 4.18 (m, 1H); calc for C 14 H 13 NO 9 P 370.0328; found by HR (APCI) [M+H] + 370.0361. [0026] General Procedure for Preparation of Narcistatin Prodrugs 3c-f. [0027] Pyridinium narcistatin (3a, 50 mg) was dissolved in water (35 ml) and the solution passed through a column (1×20 cm) of Dowex 50W-X2 bearing the respective cation. The u.v. active fractions were combined and freeze dried to give the corresponding narcistatin salt as a colorless solid unless otherwise recorded. The solubility of each in water (mg/ml) now follows: 3c, >50 mg; 3d, 60 mg; 3e, 11 mg; 3f, <13 mg. [0028] Lithium Narcistatin (3c). [0029] Yield, 65 mg, 77%; m.p. 220° C. (dec); 1 H NMR (DMSO-d 6 , 500 MHz) δ 13.79 (s, 1H), 8.71 (s, 1H), 7.07 (s, 1H), 6.49 (s, 1H), 6.13 (m, 2H), 4.36 (m, 2H), 4.04 (m, 1H), 3.93 (m, 1H); 13 C NMR (DMSO-d 6 , 300 MHz), 167.6, 152.5, 145.2, 133.3, 129.1, 127.3, 125.6, 104.3, 101.9, 94.2, 75.2, 74.6, 70.4, 53.8. [0030] Sodium Narcistatin (3d). (Procedure A). [0031] Colorless solid, 38 mg, 87%); [α] 25 D =−6.33 (c 0.3, DMSO); m.p. 275° C.; 1 H NMR (DMSO-d 6 , 500 MHz) δ 13.72 (s, 1H) 8.63 (s, 1H), 6.99 (s, 1H), 6.41 (s, 1H), 6.05 (m, 2H), 5.77 (bs, 1H), 4.26 (m, 2H), 3.4 (m, 1H), 3.83 (m, 1H); 13 C NMR (DMSO-d 6 , 500 MHz), 167.6, 152.5, 145.2, 133.3, 129.1, 127.3, 125.5, 104.3, 101.9, 94.2, 75.2, 74.5, 70.4, 53.9; 31 p (DMSO-d 6 , 200 MHz) 16.98. [0032] Sodium Narcistatin (3d). Procedure B. [0033] Narciclasine (1) (0.113 g, 0.368 mmol) was added to pyridine (4 ml) and the solution heated to 80° C. Next, tetrabutylammonium dihydrogen phosphate (0.075 g, 0.22 mmol, 0.6 equiv.) and dicyclohexylcarbodiimide (0.4 g, 1.93 mmol, 5 equiv.) were added. The reaction mixture was stirred under argon at 80° C. for 24 hours. Tetrabutylammonium dihydrogen phosphate (0.185 g) was added followed by DCCI (0.4 g) and the reaction stirred for a further 72 hours. 1 HNMR (DMSO-d 6 ) of the crude reaction mixture showed complete conversion to product. The reaction was cooled and filtered. Water (100 ml) was added to the mother liquor, which was then filtered to remove any precipitated DCU. The aqueous solution was then concentrated to minimum volume. The solution was then eluted on an ion exchange column of Dowex 50WX8-200 (sodium form) and the UV active fractions were combined and freeze dried to afford the product as a white solid (0.113 mg, 88%). Comparison of the 1 HNMR of this product in DMSO-d 6 with the narcistatin sodium salt 3d prepared from the pyridinium narcistatin 3a by the method outlined above showed them to be identical. This method is more practical and dramatically improves the yield of narcistatin from narciclasine. [0034] Potassium Narcistatin (3e) [0035] Off-white solid, 59 mg, 80%, m.p. 250° C., 1 H NMR (DMSO-d 6 , 300 MHz) δ 13.74 (s, 1H), 8.65 (s, 1H), 6.98 (s, 1H), 6.40 (s, 1H), 6.04 (d, J ab =2.4 Hz, 2H), 5.74 (bs, 1H), 4.25 (m, 2H), 3.9 (m, 1H), 3.78 (m, 1H). [0036] Cesium Narcistatin (3f) [0037] Off white solid, 51 mg, 91%, m.p. 245° C.; 1 H NMR (DMSO-d 6 , 300 MHz) δ 13.74 (s, 1H), 8.65 (s, 1H), 6.98 (s, 1H), 6.40 (s, 1H), 6.04 (m, 2H), 5.74 (bs, 1H), 4.25 (m, 2H), 3.92 (m, 1H), 3.79 (m, 1H). [0038] An alternative method was also developed to isolate yield narcistatin sodium salt 3d. Narciclasine, tetrabutylammonium dihydrogen phosphate, DCCI and pyridinium p-toluene sulfonate were allowed to react at room temperature for 2 days. The reaction was monitored by t.l.c. using the solvent system 4:3:2:1 butanol-methanol-water-concentrated aqueous ammonia. Two major fluorescent spots were evident, narciclasine at R f 0.65 and product at a higher R f 0.69. Even after 4 days of stirring, the reaction was incomplete. The reaction mixture was added to water, the DCU collected, the mother liquor was evaporated to half its volume, and 2N aqueous ammonia was added at regular intervals to maintain a pH of 8-9. The solution was passed through a column (15×15 cm) of Dowex 50 (pyridinium form) in order to remove the unreacted narciclasine. Narciclasine remained bound to the resin while the charged phosphate passed through unchanged. The column was then washed with methanol and the unreacted narciclasine was recovered. The cyclic phosphate was separated from contaminating inorganic phosphate by anion exchange chromatography using DEAE-Sephadex and gradient elution with aqueous triethyl ammonium bicarbonate. The triethyl ammonium salt was converted to the sodium salt by passage through a Dowex 50 column (Na + form). A 31 P-NMR confirmed the presence of a phosphate group. The yield from this reaction was 43%. Comparison of the 1 H NMR of this product in D 2 O with the narcistatin sodium salt 3d prepared from the pyridinium narcistatin 3a by the method outlined above showed them to be identical. However, this method proved less practical and did not significantly improve the yield. [0039] General Procedure for Preparation of Narcistatin Divalent Cation Salts 3g-j. [0040] The experiment leading to magnesium salt 3g provides the general method and relative quantities of reactants and solvents. In each case, the respective metal acetate was employed. [0041] Magnesium Narcistatin (3g) [0042] To a mixture of phosphoric acid (3b, 50 mg, 0.135 mmol) and methanol-water (3:2) was added a solution of magnesium acetate (15 mg, 0.0675 mmol. 0.5 equiv) in water (1 ml). The mixture became opaque immediately upon addition of the metal acetate and was stirred for 3 days while further precipitation occurred. The solution was concentrated to a white residue and water-methanol was added (1.4 ml). The precipitate was collected and dried; grey solid, m.p. 210° C. dec. very insoluble in water, soluble in DMSO; 1 H-NMR (DMSO-d 6 , 300 MHz) δ 13.69 (s, 1H), 8.73 (s, 1H), 6.99 (s, 1H), 6.43 (s, 1H), 6.14 (m, 1H), 6.05 (s, 2H), 5.82 (bs, 1H), 4.41-4.31 (m, 2H), 4.03-3.95 (m, 2H). Each of the divalent cation salts proved to be only sparingly soluble in water. [0043] Calcium Narcistatin (3h) [0044] Grey solid; 30 mg, m.p. 195° C. (dec). 1 H NMR (DMSO-d 6 , 300 MHz), δ 13.68 (s, 1H), 8.69 (s, 1H), 7.0 (s, 1H), 6.43 (s, 1H), 6.14 (d, J=12.9 Hz, 1H), 6.05 (m, 2H), 4.29 (m, 2H), 4.02 (m, 1H), 3.94 (m, 1H). [0045] Zinc Narcistatin (3i) [0046] Yield of grey solid, 23 mg, m.p. 200° C. (dec). 1 H NMR (DMSO-d 6 , 300 MHz), δ 13.64 (s, 1H), 8.81 (s, 1H), 6.92 (s, 1H), 6.38 (s, 1H), 6.16 (m, 1H), 6.03 (s, 2H), 5.94 (bs, 1H), 4.31 (m, 2H), 4.20-4.17 (m, 1H), 4.07 (m, 1H). [0047] Manganese Narcistatin (3j) [0048] For this experiment, 41 mg of narcistatin (3b) was treated with manganese acetate (16 mg, 0.065 mmol. 0.5 equiv) in water (1 ml) to afford 35 mg of grey solid, m.p. 165° C. (dec); 1 H NMR (DMSO-d 6 , 300 MHz). The salt, while quite soluble in DMSO-d 6 , did not give a useful spectrum. [0049] General Procedure for Obtaining Ammonium Salts 3k-o. [0050] Phosphoric acid 3b (0.25 g) was dissolved in methanol-dichloromethane-water (3:1:1) (10 ml). A 2 ml aliquot of the phosphoric acid solution was added to each of the five flasks containing 1.2 equivalents of the respective amine and the reaction mixture stirred for 24 hr at rt. A precipitate separated from the reaction mixture with the quinine and imidazole examples. The solvent was concentrated and the residues reprecipitated from water-methanol to yield each of the ammonium salts 3k-o). [0051] Quinidinium Narcistatin (3k). [0052] Cream-colored solid; 34 mg, m.p. 205° C. (dec, 220° C. melts); 1 H NMR (DMSO-d 6 , 300 MHz), δ 13.71 (s, 1H), 8.68 (bs, 2H), 7.90 (d, J=8.4 Hz, 1H), 7.52 (s, 1H), 7.37-7.40 (m, 3H), 6.99 (s, 1H), 6.4 (s, 1H), 6.13-6.01 (m, 3H), 5.10 (m, 4H), 4.25 (m, 2H), 3.92 (m, 5H), 3.6-3.2 (m, 6H), 2.42 (m, 1H), 2.2-2.12 (m, 1H), 1.91-1.84 (m, 1H), 1.60 (m, 2H), 1.47-1.38 (m, 1H). [0053] Quininium Narcistatin (3l). [0054] Cream-colored solid; 55 mg, m.p. 195° C.; 1 H NMR (DMSO-d 6 , 300 MHz), δ 13.72 (s, 1H), 8.70 (bs, 2H), 7.93 (d, J=8.4 Hz, 1H), 7.57 (bs, 1H), 7.45-7.39 (m, 3H), 6.99 (s, 1H), 6.41 (s, 1H), 6.05 (m, 3H), 5.80-5.73 (m, 2H), 5.07-4.93 (m, 2H), 4.25 (bs, 2H), 4.03-3.85 (m, 5H), 3.38 (m, 6H), 1.91 (m, 4H), 1.71 (m, 1H), 1.47 (m, 1H). [0055] Imidazolium Narcistatin (3m). [0056] Off-white solid, 39 mg, m.p. 210° C.; 1 H NMR (DMSO-d 6 300 MHz), δ 13.73 (s, 1H), 13.4 (s, 1H), 8.71 (s, 1H), 8.06 (bs, 1H), 7.21 (bm, 2H), 6.98 (s, 1H), 6.41 (s, 1H), 6.11 (bs, 1H), 6.04 (m, 2H), 4.25 (m, 2H), 3.99 (m, 1H), 3.84 (m, 1H). [0057] Morpholinium Narcistatin (3n). [0058] Off-white solid, 20 mg, m.p. 230° C.; 1 H NMR (DMSO-d 6 300 MHz), δ 13.73 (s, 1H), 8.68 (s, 1H), 6.99 (s, 1H), 6.41 (s, 1H), 6.04 (d, J=2.7 Hz, 2H), 5.76 (bs, 1H), 4.25 (bm, 2H), 3.97 (m, 1H), 3.92-3.71 (m, 5H), 3.03 (m, 4H), 1.22 (s, 1H). [0059] Piperazinium Narcistatin (3o). [0060] Off-white solid, 21 mg, m.p. 270° C.; 1 H NMR (DMSO-d 6 300 MHz), δ 13.74 (s, 1H), 8.66 (s, 1H), 6.98 (s, 1H), 6.40 (s, 1H), 6.04 (d, J=1.8 Hz, 2H), 5.74 (bs, 1H), 4.24 (bm, 2H), 3.93 (m, 1H), 3.81 (m, 1H), 3.14 (s, 2H), 2.83 (s, 9H). Administration Dosages [0061] The dosage of the presently disclosed compounds to be administered to humans and other animals requiring treatment will depend upon numerous factors, including the identity of the neoplastic disease; the type of host involved, including its age, health and weight; the kind of concurrent treatment, if any; the frequency of treatment and therapeutic ratio. Hereinafter are described various possible dosages and methods of administration, with the understanding that the following are intended to be illustrative only, and that the actual dosages to be administered, and methods of administration or delivery may vary therefrom. The proper dosages and administration forms and methods may be determined by one of skill in the art. [0062] Illustratively, dosage levels of the administered active ingredients are: intravenous, 0.1 to about 200 mg/kg; intramuscular, 1 to about 500 mg/kg; orally, 5 to about 1000 mg/kg; intranasal instillation, 5 to about 1000 mg/kg; and aerosol, 5 to about 1000 mg/k of host body weight. [0063] Expressed in terms of concentration, an active ingredient can be present in the compositions of the present invention for localized use about the cutis, intranasally, pharyngolaryngeally, bronchially, intravaginally, rectally, or ocularly in concentration of from about 0.01 to about 50% w/w of the composition; preferably about 1 to about 20% w/w of the composition; and for parenteral use in a concentration of from about 0.05 to about 50% w/v of the composition and preferably from about 5 to about 20% w/v. [0064] The compositions of the present invention are preferably presented for administration to humans and animals in unit dosage forms, such as tablets, capsules, pills, powders, granules, suppositories, sterile parenteral solutions or suspensions, sterile non-parenteral solutions of suspensions, and oral solutions or suspensions and the like, containing suitable quantities of an active ingredient. [0065] For oral administration either solid or fluid unit dosage forms can be prepared. [0066] Powders are prepared quite simply by comminuting the active ingredient to a suitably fine size and mixing with a similarly comminuted diluent. The diluent can be an edible carbohydrate material such as lactose or starch. Advantageously, a sweetening agent or sugar is present as well as a flavoring oil. [0067] Capsules are produced by preparing a powder mixture as hereinbefore described and filling into formed gelatin sheaths. Advantageously, as an adjuvant to the filling operation, a lubricant such as talc, magnesium stearate, calcium stearate and the like is added to the powder mixture before the filling operation. [0068] Soft gelatin capsules are prepared by machine encapsulation of a slurry of active ingredients with an acceptable vegetable oil, light liquid petrolatum or other inert oil or triglyceride. [0069] Tablets are made by preparing a powder mixture, granulating or slugging, adding a lubricant and pressing into tablets. The powder mixture is prepared by mixing an active ingredient, suitably comminuted, with a diluent or base such as starch, lactose, kaolin, dicalcium phosphate and the like. The powder mixture can be granulated by wetting with a binder such as corn syrup, gelatin solution, methylcellulose solution or acacia mucilage and forcing through a screen. As an alternative to granulating, the powder mixture can be slugged, i.e., run through the tablet machine and the resulting imperfectly formed tablets broken into pieces (slugs). The slugs can be lubricated to prevent sticking to the tablet-forming dies by means of the addition of stearic acid, a stearic salt, talc or mineral oil. The lubricated mixture is then compressed into tablets. [0070] Advantageously, the tablet can be provided with a protective coating consisting of a sealing coat or enteric coat of shellac, a coating of sugar and methylcellulose and polish coating of carnauba wax. [0071] Fluid unit dosage forms for oral administration such as in syrups, elixirs and suspensions can be prepared wherein each teaspoonful of composition contains a predetermined amount of an active ingredient for administration. [0072] The water-soluble forms can be dissolved in an aqueous vehicle together with sugar, flavoring agents and preservatives to form a syrup. An elixir is prepared by using a hydroalcoholic vehicle with suitable sweeteners together with a flavoring agent. Suspensions can be prepared of the insoluble forms with a suitable vehicle with the aid of a suspending agent such as acacia, tragacanth, methylcellulose and the like. [0073] For parenteral administration, fluid unit dosage forms are prepared utilizing an active ingredient and a sterile vehicle, water being preferred. The active ingredient, depending on the form and concentration used, can be either suspended or dissolved in the vehicle. In preparing solutions the water-soluble active ingredient can be dissolved in water for injection and filter sterilized before filling into a suitable vial or ampule and sealing. Advantageously, adjuvants such as a local anesthetic, preservative and buffering agents can be dissolved in the vehicle. Parenteral suspensions are prepared in substantially the same manner except that an active ingredient is suspended in the vehicle instead of being dissolved and sterilization cannot be accomplished by filtration. The active ingredient can be sterilized by exposure to ethylene oxide before suspending in the sterile vehicle. Advantageously, a surfactant or wetting agent is included in the composition to facilitate uniform distribution of the active ingredient. [0074] In addition to oral and parenteral administration, the rectal and vaginal routes can be utilized. An active ingredient can be administered by means of a suppository. A vehicle which has a melting point at about body temperature or one that is readily soluble can be utilized. For example, cocoa butter and various polyethylene glycols (Carbowaxes) can serve as the vehicle. [0075] For intranasal installation, a fluid unit dosage form is prepared utilizing an active ingredient and a suitable pharmaceutical vehicle, preferably purified (P.F.) water, a dry powder, can be formulated when insulation is the administration of choice. [0076] For use as aerosols, the active ingredients can be packaged in a pressurized aerosal container together with a gaseous or liquefied propellant, for example, dichlorodifluoromethane, carbon dioxide, nitrogen, propane, and the like, with the usual adjuvants such as cosolvents and wetting agents, as may be necessary or desirable. [0077] The term “unit dosage form” as used in the specification and claims refers to physically discrete units suitable as unitary dosages for human and animal subjects, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect in association with the required pharmaceutical diluent, carrier or vehicle. The specifications for the novel unit dosage forms of this invention are dictated by and are directly dependent on (a) the unique characteristics of the active material and the particular therapeutic effect to be achieved, and (b) the limitation inherent in the art of compounding such an active material for therapeutic use in humans, as disclosed in this specification, these being features of the present invention. Examples of suitable unit dosage forms in accord with this invention are tablets, capsules, troches, suppositories, powder packets, wafers, cachets, teaspoonfuls, tablespoonfuls, dropperfuls, ampules, vials, segregated multiples of any of the foregoing, and other forms as herein described. [0078] The active ingredients to be employed as antineoplastic agents can be easily prepared in such unit dosage form with the employment of pharmaceutical materials which themselves are available in the art and can be prepared by established procedures. The following preparations are illustrative of the preparation of the unit dosage forms of the present invention, and not as a limitation thereof. Several dosage forms were prepared embodying the present invention. They are shown in the following examples in which the notation “active ingredient” signifies one or more of the compounds described herein. Composition “A” Hard-Gelatin Capsules [0079] One thousand two-piece hard gelatin capsules for oral use, each capsule containing 200 mg of an active ingredient are prepared from the following types and amounts of ingredients: [0000] Active ingredient, micronized 200 g  Corn Starch 20 g Talc 20 g Magnesium stearate  2 g [0080] The active ingredient, finely divided by means of an air micronizer, is added to the other finely powdered ingredients, mixed thoroughly and then encapsulated in the usual manner. [0081] The foregoing capsules are useful for treating a neoplastic disease by the oral administration of one or two capsules one to four times a day. [0082] Using the procedure above, capsules are similarly prepared containing an active ingredient in 50, 250 and 500 mg amounts by substituting 50 g, 250 g and 500 g of an active ingredient for the 200 g used above. Composition “B” Soft Gelatin Capsules [0083] One-piece soft gelatin capsules for oral use, each containing 200 mg of an active ingredient, finely divided by means of an air micronizer, are prepared by first suspending the compound in 0.5 ml of corn oil to render the material capsulatable and then encapsulating in the above manner. [0084] The foregoing capsules are useful for treating a neoplastic disease by the oral administration of one or two capsules one to four times a day. Composition “C” Tablets [0085] One thousand tablets, each containing 200 mg of an active ingredient, are prepared from the following types and amounts of ingredients: [0000] Active ingredient, micronized 200 g Lactose 300 g Corn starch  50 g Magnesium stearate  4 g Light liquid petrolatum  5 g [0086] The active ingredient, finely divided by means of an air micronizer, is added to the other ingredients and then thoroughly mixed and slugged. The slugs are broken down by forcing them through a Number Sixteen screen. The resulting granules are then compressed into tablets, each tablet containing 200 mg of the active ingredient. [0087] The foregoing tablets are useful for treating a neoplastic disease by the oral administration of one or two tablets one to four times a day. [0088] Using the procedure above, tablets are similarly prepared containing an active ingredient in 250 mg and 100 mg amounts by substituting 250 g and 100 g of an active ingredient for the 200 g used above. Composition “D” Oral Suspension [0089] One liter of an aqueous suspension for oral use, containing in each teaspoonful (5 ml) dose, 50 mg of an active ingredient, is prepared from the following types and amounts of ingredients: [0000] Active ingredient, micronized 10 g Citric acid 2 g Benzoic acid 1 g Sucrose 790 g Tragacanth 5 g Lemon Oil 2 g Deionized water, q.s. 1000 ml [0090] The citric acid, benzoic acid, sucrose, tragacanth and lemon oil are dispersed in sufficient water to make 850 ml of suspension. The active ingredient, finely divided by means of an air micronizer, is stirred into the syrup unit uniformly distributed. Sufficient water is added to make 1000 ml. [0091] The composition so prepared is useful for treating a neoplastic disease at a dose of 1 teaspoonful (15 ml) three times a day. Composition “E” Parenteral Product [0092] A sterile aqueous suspension for parenteral injection, containing 30 mg of an active ingredient in each milliliter for treating a neoplastic disease, is prepared from the following types and amounts of ingredients: [0000] Active ingredient, micronized 30 g POLYSORBATE 80 5 g Methylparaben 2.5 g Propylparaben 0.17 g Water for injection, q.s. 1000 ml. [0093] All the ingredients, except the active ingredient, are dissolved in the water and the solution sterilized by filtration. To the sterile solution is added the sterilized active ingredient, finely divided by means of an air micronizer, and the final suspension is filled into sterile vials and the vials sealed. [0094] The composition so prepared is useful for treating a neoplastic disease at a dose of 1 milliliter (1 ml) three times a day. Composition “F” Suppository, Rectal and Vaginal [0095] One thousand suppositories, each weighing 2.5 g and containing 200 mg of an active ingredient are prepared from the following types and amounts of ingredients: [0000] Active ingredient, micronized   15 g Propylene glycol   150 g Polyethylene glycol #4000, q.s. 2,500 g [0096] The active ingredient is finely divided by means of an air micronizer and added to the propylene glycol and the mixture passed through a colloid mill until uniformly dispersed. The polyethylene glycol is melted and the propylene glycol dispersion is added slowly with stirring. The suspension is poured into unchilled molds at 40° C. The composition is allowed to cool and solidify and then removed from the mold and each suppository foil wrapped. [0097] The foregoing suppositories are inserted rectally or vaginally for treating a neoplastic disease. Composition “G” Intranasal Suspension [0098] One liter of a sterile aqueous suspension for intranasal instillation, containing 20 mg of an active ingredient in each milliliter, is prepared from the following types and amounts of ingredients: [0000] Active ingredient, micronized 15 g POLYSORBATE 80 5 g Methylparaben 2.5 g Propylparaben 0.17 g Deionized water, q.s. 1000 ml. [0099] All the ingredients, except the active ingredient, are dissolved in the water and the solution sterilized by filtration. To the sterile solution is added the sterilized active ingredient, finely divided by means of an air micronizer, and the final suspension is aseptically filled into sterile containers. [0100] The composition so prepared is useful for treating a neoplastic disease, by intranasal instillation of 0.2 to 0.5 ml given one to four times per day. [0101] An active ingredient can also be present in the undiluted pure form for use locally about the cutis, intranasally, pharyngolaryngeally, bronchially, or orally. Composition “H” Powder [0102] Five grams of an active ingredient in bulk form is finely divided by means of an air micronizer. The micronized powder is placed in a shaker-type container. [0103] The foregoing composition is useful for treating a neoplastic disease, at localized sites by applying a powder one to four times per day. Composition “I” Oral Powder [0104] One hundred grams of an active ingredient in bulk form is finely divided by means of an air micronizer. The micronized powder is divided into individual doses of 200 mg and packaged. [0105] The foregoing powders are useful for treating a neoplastic disease, by the oral administration of one or two powders suspended in a glass of water, one to four times per day. Composition “J” Insulation [0106] One hundred grams of an active ingredient in bulk form is finely divided by means of an air micronizer. [0107] The foregoing composition is useful for treating a neoplastic disease, by the inhalation of 300 mg one to four times a day. [0108] It is of course understood that such modifications, alterations and adaptations as will readily occur to the artisan confronted with this disclosure are intended within the spirit of the present invention. [0000] TABLE 1 Solubilities, Human Cancer Cell Line and Murine P-388 Lymphocytic Inhibitory Activities of Cyclic Phosphates 3-16. ED 50 (μg/ml) GI 50 (μg/ml) Compound Solubilities a Leukemia Pancreas-a Breast CNS Lung-NSC Colon Prostate — (mg/ml) P388 BXPC-3 MCF-7 SF 268 NCI-H460 KM20L2 DU-145 3a 7 1.91 × 10 −1 2.2 × 10 −1 2.7 × 10 −1 1.5 × 10 −1 2.7 × 10 −1 3.4 × 10 −1 1.7 × 10 −1 3b 4 2.75 × 10 −1 3.3 × 10 −1 3.5 × 10 −1 2.2 × 10 −1 4.7 × 10 −1 5.3 × 10 −1 1.6 × 10 −1 3c >50 1.21 × 10 −1 2.5 × 10 −1 3.1 × 10 −1 1.7 × 10 −1 3.0 × 10 −1 2.6 × 10 −1 1.3 × 10 −1 3d 60 2.55 × 10 −1 3.2 × 10 −1 5.6 × 10 −1 2.3 × 10 −1 >1 4.5 × 10 −1 1.2 × 10 −1 3e 11 2.42 × 10 −1 3.6 × 10 −1 4.0 × 10 −1 1.9 × 10 −1 6.7 × 10 −1 5.6 × 10 −1 2.6 × 10 −1 3f <13 1.83 × 10 −1 4.1 × 10 −1 6.2 × 10 −1 3.3 × 10 −1 >1 6.6 × 10 −1 1.3 × 10 −1 3g <1.5 1.70 × 10 −1 1.9 × 10 −1 2.5 × 10 −1 1.4 × 10 −1 2.9 × 10 −1 3.1 × 10 −1 1.0 × 10 −1 3h <1 2.23 × 10 −2 4.5 × 10 −2 5.9 × 10 −2 3.1 × 10 −2 1.2 × 10 −1 5.9 × 10 −2 9.3 × 10 −3 3i 1.7 2.87 × 10 −2 6.9 × 10 −2 1.4 × 10 −1 5.3 × 10 −2 2.1 × 10 −1 1.6 × 10 −1 1.6 × 10 −2 3j <3 4.27 × 10 −2 4.9 × 10 −2 7.0 × 10 −2 4.0 × 10 −2 1.5 × 10 −1 1.3 × 10 −1 3.4 × 10 −2 3k <1 2.71 × 10 −1 3.1 × 10 −1 5.0 × 10 −1 2.5 × 10 −1 7.7 × 10 −1 5.8 × 10 −1 2.2 × 10 −1 3l <1 3.42 × 10 −2 5.1 × 10 −2 1.2 × 10 −1 4.5 × 10 −2 1.7 × 10 −1 1.2 × 10 −1 1.3 × 10 −2 3m 5.8 2.40 × 10 −1 4.5 × 10 −1 9.0 × 10 −1 3.8 × 10 −1 >1 >1 4.4 × 10 −1 3n >13 2.32 × 10 −1 2.5 × 10 −1 4.8 × 10 −1 2.4 × 10 −1 >1 5.4 × 10 −1 1.4 × 10 −1 3o 1.9 3.78 × 10 −2 1.0 × 10 −1 1.7 × 10 −1 9.9 × 10 −2 2.4 × 10 −1 2.2 × 10 −1 3.2 × 10 −2 a Solubility values were obtained using 1 ml distilled water at 25° C.

The present invention provides prodrugs derived from the sparingly soluble anticancer isocarbostyril narciclasine, a component of various Narcissus species, said prodrugs having potential for use against animal and human cancers. Also disclosed is an efficient procedure for the synthetic conversion of narciclasine to several more soluble cyclic phosphate compounds, including “narcistatin”.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This Application claims the benefit of U.S. Provisional Application 61/329,960 filed on Apr. 30, 2010. BACKGROUND OF INVENTION [0002] A variety of subsea control systems are employed for use in controlling subsea wells during, for example, emergency shutdowns. In many applications, the subsea systems may comprise a number of electrical lines that may be used to control a number of valves. During a specific valve operation, an operations engineer may issue a command via a human machine interface from a topside master controller station. The umbilical may be operationally connected to surface sources of power (e.g., electrical and hydraulic) in addition to electronics, communications, and power that may be provided via the topside master control station. For example, control signals may be sent down the umbilical to operate a number of solenoid valves and a subsea control module to actuate a number of directional control valves. [0003] The umbilical spans the distance necessary to reach the various components of the subsea control systems, which may be located thousands of meters below the sea surface. Thus, the subsea electrical lines and components are difficult to reach while deployed subsea. Accordingly, there remains a need to easily diagnose the integrity of the subsea portions of the umbilical and other electrical lines used to control the various subsea components from the topside master controlled station to ensure the proper operation of, for example, the safety control features of the subsea control system. SUMMARY OF INVENTION [0004] In general, in one aspect, the invention relates to a ground fault detection circuit for detecting ground faults in electrical subsea conductor lines, including a first electrical conductor line, a second electrical conductor line, a first ground fault detection line, a second ground fault detection line, a voltage source, a first resistor operatively connected to the voltage source and the first ground fault detection line, a second resistor operatively connected to the voltage source and the second ground fault detection line, and a voltage detection device configured to detect the voltage at an output end of the first resistor to determine the presence of a ground fault in at least one of the first and second conductor lines. [0005] In general, in one aspect, the invention relates to a ground fault detection system for detecting ground faults in electrical subsea conductor lines including a power supply unit, a ground fault detection circuit, a line enable switching module, and a voltage detection device. One or more embodiments of the ground fault detection system may include a power supply unit that is configured to supply power to the ground fault detection circuit and a subsea load. [0006] In general, in one aspect, the invention relates to a method for detecting ground faults in electrical subsea conductor lines using a ground fault detection system, the method including operatively connecting a first resistor between a voltage source and a first ground fault detection line in a ground fault detection circuit, operatively connecting a second resistor between the voltage source and a second ground fault detection line the ground fault detection circuit, and detecting a voltage at an output end of the first resistor to determine the presence of a ground fault in at least one of the first and second conductor lines. [0007] Other aspects and advantages of the invention will be apparent from the following description and the appended claims. BRIEF DESCRIPTION OF DRAWINGS [0008] FIG. 1 illustrates a subsea production well testing system in accordance with one or more embodiments of the invention. [0009] FIG. 2A is a block diagram of a ground fault detection system in accordance with one or more embodiments of the invention. [0010] FIGS. 2B-2C are block diagrams of ground fault detection circuits in accordance with one or more embodiments of the invention. [0011] FIGS. 3A-3B are schematic diagrams of ground fault detection circuits in accordance with one or more embodiments of the invention. DETAILED DESCRIPTION [0012] Specific embodiments of the invention will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. [0013] In the following detailed description of embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description. [0014] In general, embodiments of the invention relate to an apparatus and method for detecting ground faults in a subsea control system. More specifically, embodiments of the invention provide an apparatus and method for detecting electrical line shorts to earth ground for electrical lines used to power various subsea well components, for example, test trees and their control systems, tubing hanger running tools, and subsea valves. In accordance with one or more embodiments of the invention, a ground fault detection apparatus may continuously monitor electrical subsea conductor lines for leakage to earth ground so as to provide an indication of a shorted electrical line. Under a ground fault condition, the attempted operation of a shorted electrical line may lead to tool failure and/or damage to sensitive electronics, e.g., the power supply units. [0015] FIG. 1 illustrates a subsea production well testing system 100 which may be employed to test production characteristics of a well, in accordance with one or more embodiments of the invention. Subsea production well testing system 100 includes a vessel 102 which is positioned on a water surface 104 and a riser 106 which connects vessel 102 to a blowout preventer (“BOP”) stack 108 on seafloor 110 . A well 112 is drilled into seafloor 110 , and a tubing string 114 extends from vessel 102 through BOP stack 108 into well 112 . Tubing string 114 is provided with a bore 116 through which hydrocarbons or other formation fluids can be conducted from well 112 to the surface during production testing of the well. [0016] Well testing system 100 includes a safety shut-in system 118 which provides automatic shut-in of well 112 when conditions on vessel 102 or in well 112 deviate from preset limits. Safety shut-in system 118 includes a subsea tree 120 (e.g., subsea test tree, “SSTT”), a subsea tree control system 10 , a topside master control station 5 and various subsea safety valves (“SV”) such as valve assembly 124 , and one or more blowout preventer stack rams. [0017] Umbilical 136 includes conductor lines connecting a topside master control station 5 to subsea tree control system 10 . Furthermore, umbilical 136 is often required to extend to great length, for example 12,500 feet (3,810 m) or more. Umbilical 136 includes one or more conductor lines for transmitting signals from the surface to the subsea control system. [0018] In the illustrated embodiment, subsea tree control system 10 is a modular unit that includes a subsea electronics module (“SEM”) 12 and a hydraulic valve and manifold pod 14 . Subsea tree control system 10 may include other elements such as hydraulic accumulators, electric power sources and the like. Subsea control system 10 is positioned below water surface 104 and proximate to tree 120 in this embodiment. Umbilical 136 may be operationally connected to surface sources of power (e.g., electrical, hydraulic) in addition to electronics, communications, and power that may be provided via topside master control station 5 . Subsea tree control safety system 10 may be positioned in various positions within riser 106 . [0019] Ground faults may occur in subsea systems when, for example, any part of an electrical power line operatively connected to a subsea component makes electrical contact (or “shorts”) to any conductive part of the subsea production well testing system, for example, a subsea test tree. As described herein, a “ground fault” is a low impedance electrical path, or connection, to earth ground in one or more places along the electrical power line. [0020] FIG. 2A is a block diagram of a ground fault detection system in accordance with one or more embodiments of the invention. According to this embodiment, the ground fault detection system 200 includes power supply unit 201 , ground fault detection circuit 203 , line enable relay module 205 , and load 207 . One of ordinary skill will appreciate that many different types of loads may be driven with the ground fault detection system 200 . For illustrative purposes only, load 207 is shown as a solenoid valve in FIG. 2A . In accordance with one or more embodiments, power supply unit 201 may be provided, for example, within a vessel as part of topside master control station as shown in FIG. 1 . Furthermore, fault detection circuit 203 and line enable relay module 205 , may both be provided as part of a subsea tree control safety system, or the like. The particular configuration of the individual components comprising the ground fault detection system 200 are shown as illustrative examples, only. Accordingly, one of ordinary skill will appreciate that any or all of the power supply units 209 and 201 , the fault detection circuit 203 , or the line enable relay module 205 may alternatively be located at any convenient subsea (e.g., at any location within the riser) or topside location without departing from the scope of the present invention. [0021] Power supply unit 201 may include fault detection circuit power supply 209 and load power supply unit 211 . In accordance with one or more embodiments, load power supply unit 211 may be configured as a current source. Accordingly, load power supply unit 211 includes current source line 221 and current return line 223 . Furthermore, in accordance with one or more embodiments of the invention, fault detection circuit power supply 209 may be configured as a regulated DC power supply that includes ground fault detector lines 225 and 227 . In accordance with one or more embodiments, lines 221 , 223 , 225 , and 227 may be incorporated along with all the other necessary control, power, hydraulic, etc., lines into the umbilical 136 . One of ordinary skill will appreciate that the block diagram of power supply unit 201 , shown in FIG. 2A , is greatly simplified. Accordingly, many other known elements may be included within power supply unit 201 , depending on, for example, the particular type and number of subsea loads being driven, e.g., flapper valves, ball valves, solenoid valves, retainer valves, pipe ram seals, shear ram seals, etc. For example, in certain embodiments, dual polarity power may be required to operate the load, in which case, a polarity relay module may be included. Furthermore, various additional control electronics, such as multiplexors and demultiplexors may be implemented to allow for multiple load control and multiple line ground fault detection. [0022] Line enable relay module 205 is configured to allow for switching between two configurations, a fault detect configuration and normal configuration (not shown). Under fault detect configuration, electrical subsea conductor lines 237 and 239 may be connected to ground fault detection lines 225 and 227 , respectively. Alternatively, under normal configuration, electrical subsea conductor lines 237 and 239 may be connected to current source line 221 and current return line 223 , respectively. In accordance with one or more embodiments of the invention, the line enable relay module 205 may be configured to default to the fault detect configuration, i.e., fault detect power lines 225 and 227 are wired to the normally closed terminals of their respective relays on the line enable relay module 205 . In accordance with one or more embodiments, the ground fault detection system may be configured to detect ground faults when in an idle state (i.e., when no subsea loads are being powered). One of ordinary skill will appreciate that the electrical subsea conductor lines 237 and 239 may be switched in a variety of ways using any switching device known in the art, e.g., by using solid state switches, mechanical relays, multiplex/demultiplexors, etc. [0023] While FIG. 2A shows the ground fault detection system in the context of control lines for a solenoid valve, one of ordinary skill will appreciate that without departing from the scope of the present disclosure, the ground fault detection system may be used to detect ground faults in any electrical line, regardless of the specific type of equipment being employed. [0024] FIG. 2B is a block diagram of a ground fault detection circuit in accordance with one or more embodiments of the invention. Ground fault detection circuit 203 includes resistors 229 and 231 , blocking diodes 233 and 235 , and fault detection nodes 217 and 219 . The values of resistors 229 and 231 are not critical to the operation of fault detection circuit 203 . In accordance with one or more embodiments, resistors 229 and 231 may be within a range of 1-10 kΩ or, alternatively, within a range of 1-20 MΩ. The voltage at fault detection nodes 217 and 219 may be independently monitored with any voltage monitor known in the art. For example, FIG. 2A-2C show the nodes being monitored via a programmable logic controller (“PLC”) digital input card. Preferably, the fault detection circuit 203 is deployed subsea along with the subsea electronics module. Thus, the PLC may also be deployed either subsea or topside. Furthermore, the fault detection circuit 203 may alternatively be deployed topside, in which case the PLC may also be deployed topside. Blocking diodes 233 and 235 are optional and serve to protect fault detection circuit power supply 209 and the voltage monitor. [0025] During activation (configuration not shown) of the load 207 , load power supply unit 211 is operatively connected to load 207 , through relays 213 and 215 . Thus, under operational configuration, load power supply unit 211 may provide power to load 207 . In accordance with one or more embodiments of the invention, load power supply unit 211 may be configured as a current source that provides a constant current to solenoid valve 207 . [0026] Under fault detect configuration, as shown in FIG. 2A , fault detection circuit power supply 209 may be electrically connected through relays 213 and 215 to load 207 . If a ground fault is not present anywhere in the circuit beginning at the fault detection circuit power supply 209 and terminating at the load 207 , all points in the circuit will be at the fault detection circuit power supply 209 voltage, or 24V in this example. Thus, any voltage detection devices placed at nodes 217 and 219 may read a voltage equivalent to the fault detection circuit power supply 209 voltage. [0027] Under the conditions where a ground fault has occurred in one or both of lines 237 and 239 , the voltage at one of, or both, of the nodes 217 and 219 drops to a low value, nearly zero, in this example. The low voltage present at nodes 217 and 219 induced by the ground fault may be detected by any known voltage detection device and the output of the detection device may be used to, for example, inform an operator of the ground fault. Furthermore, the detection of a ground fault may trigger an automated response that initiates an appropriate safety protocol, for example, by diverting control to one or more backup valves and, in addition, by disabling any valves that may be electrically connected to the shorted control line or lines. [0028] FIG. 2C shows a block diagram of a fault detection circuit in accordance with one or more embodiments of the invention. In FIG. 2C , FETs 241 and 243 are included to increase the reliability of the voltage detection made at the nodes 217 and 219 . The FETs 241 and 243 are configured in such a way as to have their respective gate terminals connected to nodes 217 and 219 , thereby isolating any voltage detection devices from the rest of the fault detection circuit through the high impedance gate-to-source path. In accordance with one or more embodiments, FETs 241 and 243 are P-channel MOSFETs, but other types of transistors may be used, for example, N-channel MOSFETs or bipolar junction transistors. Accordingly, under normal operating conditions (i.e., no ground fault present, 24V at nodes 217 and 219 ), the voltage measured by a voltage detection device (e.g., a PLC digital input card) at the FET drain terminals is in a low state. In the event of a ground fault, the voltage measured at the FET drain terminals will be in a high state. [0029] While FIGS. 2B-2C show block diagrams of ground fault detection circuits that monitor only one set of electrical subsea conductor lines, the ground fault detection system disclosed herein need not be so limited. For example, using the same operational principles outlined about, the ground fault detection system may be extended to multi-component/multi-control line systems. FIGS. 3A and 3B show examples of a multi-line fault detection circuits, corresponding to FIGS. 2B and 2C , respectively, in accordance with one or more embodiments of the invention. FIGS. 3A-3B show examples of ground fault detection circuits with seven sub-units configured in a parallel configuration. Each sub-unit of the multi-component fault detection circuits shown in FIGS. 3A-3B operates in a substantially similar way to that described above for the single component examples. [0030] FIG. 3A shows a multiple sub-unit parallel combination ground fault detection circuit with a sub-unit design that corresponds to that shown in FIG. 2B . Specifically, fault detection circuit power supply 309 corresponds to fault detection circuit power supply 209 and provides power to ground fault detection lines 325 a - 325 g . Likewise, outputs 337 a - 337 g may be connected to a number of corresponding electrical subsea conductor lines via, for example, a multichannel line enable relay module (not shown). In accordance with one or more embodiments, outputs 339 a - 339 g may be connected to the input channels of a multichannel voltage detection device, as described with reference to FIGS. 2A-2C (e.g., a PLC digital input card). [0031] FIG. 3B shows a multiple sub-unit parallel combination ground fault detection circuit with a sub-unit design that corresponds to that shown in FIG. 2C . Specifically, fault detection circuit power supply 309 corresponds to fault detection circuit power supply 209 and provides power to ground fault detection lines 325 a - 325 g . Likewise, outputs 337 a - 337 g may be connected to a number of corresponding electrical subsea conductor lines via, for example, a multichannel line enable relay module (not shown). In accordance with one or more embodiments, outputs 339 a - 339 g may be connected to the input channels of a multichannel voltage detection device, as described with reference to FIGS. 2A-2C (e.g., a PLC digital input card). P-channel MOSFETS 341 a - 341 g may be used to increase the input impedance to the voltage detection device, as described above with reference to FIG. 2C . In addition, by incorporating two resistors into ground fault detection lines 325 a - 325 g , as shown, the gate voltage to the P-channel MOSFET may be set appropriately. Optionally, for increased reliability, Zener diodes may be wired from gate to source to protect P-channel MOSFETS 341 a - 341 g from high transient voltage spikes (e.g., from electrostatic discharge, or inductive kick back from a switching solenoid valve). One of ordinary skill will appreciate that many different types of transistors and resistors may be used without departing from the scope of the present disclosure. In addition, the appropriate choice of resistance values for the resistors depends on many factors, including but not limited to, the type of transistor used and value of DC voltage provided by the fault detection circuit power supply 309 . [0032] Additional circuitry may be implemented in conjunction with the circuits shown in FIGS. 3A-3B . For example, corresponding multiplexing circuitry and/or multi-channel line enable relay modules may allow for the system to monitor several different sets of subsea conductor lines for driving a number of loads. One of ordinary skill will appreciate that, with the appropriate choice of power supply unit, and monitoring equipment, any number of lines may be monitored without departing from the scope of the present disclosure. Furthermore, as with FIGS. 2B-2C , blocking diodes in line with ground fault detection lines 325 a - 325 g are optional and serve to protect the ground fault detection circuit power supply and PLC digital input card. [0033] While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims

A ground fault detection circuit for detecting ground faults in electrical subsea conductor lines including a first electrical conductor line, a second electrical conductor line, a first ground fault detection line, and a second ground fault detection line. The ground fault detection circuit further includes a first resistor operatively connected to a voltage source and the first ground fault detection line, a second resistor operatively connected to the voltage source and the second ground fault detection line, and a voltage detection device configured to detect the voltage at an output end of the first resistor to determine the presence of a ground fault in at least one of the first and second conductor lines.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] None FEDERALLY SPONSORED RESEARCH [0002] None. SEQUENCE LISTING [0003] None. BACKGROUND Prior Art [0004] The following is a tabulation of some prior art that presently appears relevant: U.S. Patents [0005] [0000] Patent Number Kind Code Issue Date Patentee 5,465,115 B1 Nov. 7, 1995 Conrad, et al. 5,764,283 B1 Jun. 9, 1998 Pingali, et al. 5,973,732 B1 Oct. 26, 1999 Guthrie 6,712,269 B1 Mar. 30, 2004 Watkins 7,612,796 B1 Nov. 3, 2009 Lev-Ran, et al. 7,692,684 B1 Apr. 6, 2010 Ku, et al. 7,903,141 B1 Mar. 8, 2011 Mariano, et al. 8,224,026 B1 Jul. 17, 2012 Golan, et al. 8,229,781 B1 Jul. 24, 2012 Zenor, et al. U.S. Patent Application Publications [0006] [0000] Publication Nr. Kind Code Publ. Date Applicant 20100021009 A1 Jan. 28, 2010 Yao 20120128212 A1 May 24, 2012 Almbladh 20120188370 A1 Jul. 26, 2012 Bordonaro 20120274755 A1 Nov. 1, 2012 Sinha; Aniruddha; et al. [0007] There are many reasons for obtaining information of traffic into consumer locations including recognizing customer counts, determining sales efficiency, estimating customer demographics, and organizing and scheduling the availability of sales people. There are numerous commercial means for obtaining this information, including human observation, both direct and through a surveillance system, tracking by infrared beams, tracking by infrared cameras and evaluation of sales records. These methods suffer from issues with heavy traffic periods, multiple entrance events, consistency and reliability. What is often desired is a system that allows rapid review of the incoming traffic stream to allow management to audit the accuracy of counts and observe the traffic demographics so that assessment can be made of the advertisement targets. It is additionally advantageous if the monitoring system is inexpensive, reviewable both locally and by remote management, is easily installed and maintained and inconspicuous. [0008] It is a tribute to the economic need for traffic information that there have been a number of patents issued in this area. The following discusses some of the prior art. [0009] Conrad, et al. recognized the need for reducing the computations by focusing on a reduced area within a video frame, but required “a linear array of gates consecutively positioned” and looking for “traversing said zone by examining consecutive segments”, “movement transverse to said linear array of gates”, “transverse to said linear array of gates”, “traversing said window by examining consecutive gates”, “traversing said window by examining consecutive gates which are occupied”, or “distinguishing objects of measurement traversing said window by examining consecutive gates”. Gates are defined as: “The window is divided into a number of narrow sectors called gates. These gates are narrow enough so that a person would normally occupy several gates at any one time.” The current invention does not contemplate the reduction into gates and the area 1 and the area 2 need not be confined to contiguous areas and area 2 is independently evaluated and usually separated from area 1. The intention of the windows in Conrad's patent is specified as “the foregoing objectives are realized by using a video imager located above a busy traffic zone”. The present invention works with any camera location, [0010] Guthrie in his patent has a camera recording a “controlled space” and tracks movement within the controlled space without extracting from the controlled space the region of interest in order to reduce computation. Additionally, counts are made “once the object has moved a predetermined distance”, as opposed to the boundary tests used in this invention. Similarly, Pingali in his patent treats the “video frame” without extracting from the video frame the region of interest in order to reduce computation. [0011] Watkins discusses the general abstract evaluation of motion but does not discuss the combination which involves the subtraction from the image of the much lesser area of interest in order to reduce the computational capability of the system. He also specifies using only the grayness level rather than the total available information in a YUYV or RGB representation. [0012] Lev-Ran, et al. in patent U.S. Pat. No. 7,612,796 refers to a directional determination accomplished in FIG. 8 , which contains only the steps of initialization, detection, matching and counting, with no discussion of the functions contained in each block. The specification appears to indicate that a body leaving an area labeled “exit” is leaving the area of interest and one leaving an area labeled “entrance” is entering. This is not the directional definition used in the invention presented here. [0013] Mariano et al. evaluates pixel regions in a traffic system, but relates regions with “scene events”, defined as “a sequence of scene descriptions, where a scene description is the plurality of regions of interest, each with its state of occlusion”. “Each scene event is manually defined when the system is initialized.” Such scene events are not required in the present invention. [0014] Golan, in his patent, requires the background surface “includes a plurality of detectable features on the surface”, a requirement not present in the current patent. [0015] Zenor, in his patent, discusses the advantage of linking consumer traffic data with in-person data which this invention enables by supplying an image linked to the traffic count. Ku attempts to evaluate accuracy by requiring both an entry and an exit count, while this invention requires only an entry or exit determination and allows an accuracy review by the rapid image scan of an associated image. [0016] The application of Yao (20100021009) uses a comparison of a current region “with the target region of the previous frame based on an online feature selection to establish a match tracking link”. The current invention uses neither an online feature selection or a tracking link. [0017] The application of Almbladh (20120128212) requires the calculation of a speed parameter used in the calculations, a step necessary in the offered invention. [0018] The application of Sinha (20120274755) uses descriptors of image comprising background modeling, Histogram of Oriented Gradients (HOG) and Haar like wavelet; all of which are not utilized in the invention presented here. [0019] Bordonaro (app. 20120188370) provides no guidance on monitoring technology, specifying, for example, element 102 in FIG. 1 (the first flowchart block) requires “Providing computer and software program for monitoring, recognizing, tracking entities within boundaries”. The invention presented provides a means for this. [0020] There are a number of additional previous patents and applications that specify the analysis of a full frame without the additional step of extracting from the full frame a smaller region. These often include the tracking of a body across the entire frame and from the computational requirements do not fall within the application of this invention. SUMMARY [0021] A system is described for a providing a microprocessor-controlled camera system for monitoring of consumer traffic to provide detection of incoming traffic, separation outgoing traffic and providing a count, time stamping and image record of each incoming body (person, car, etc.). The image provides a means of verifying the accuracy of the count by allowing the deletion of non-customer traffic such as sales people, mailmen, delivery people, etc. and allows correction of such issues as lumped bodies. The image further allows management to obtain demographics, such as customer age and sex, to allow targeted advertisement. The described system reduces the analysis by extracting from the image one or more areas through which the traffic passes and applies to the areas described algorithms to locate and track moving bodies. When the body is identified to be in a desired class (incoming, exiting or both) the image from which the determination was made is saved in a traffic record together with such pertinent data as time and location. The records are presented in a form allowing review of each image and review of statistical data from all records. ADVANTAGES [0022] The described system has the advantage of the ability to extract from a camera image a restricted area in which bodies are counted and presents several methods whereby the count qualification can be accomplished with minimum calculation. A method of triggering the tracking only on the detection of activity in another area, e.g. a door opening, allows counting in a high background area. [0023] Most inexpensive video cameras deliver a pixel-based image, e.g. the YUYV format. With VGA resolution (307200 pixels or 714400 bytes in YUYV) and if a rate of 10 frames per second is required for sufficiently small incremental movement, more than 7 MBytes of data must be analyzed each second in addition to overhead, operating system, data management and usually an Ethernet connection. Data compression can reduce the data management but the computation involved in the compression makes this unattractive for limited systems. This is not a problem for PC-sized systems but makes full-screen computation beyond the capability of less expensive processing systems. For example OpenCV has many full-screen functions for tracking (e.g. http://www.neuroforge.co.uk/index.php/tracking-methods-in-opencv) illustrating full-screen, high-capacity computer solutions but these techniques are not applicable to small, inexpensive processors. [0024] In many traffic monitoring systems there is background traffic that is not to be counted, with the focus of interest only in a small entrance region. This invention describes a means for traffic monitoring using inexpensive hardware with limited computational power. FIGURES [0025] FIG. 1 shows one method of extracting bodies by comparing a line of pixels or pixel groupings to the values from the immediate preceding image, [0026] FIG. 2 shows how to correlate the overlap of bodies on two lines and identify related bodies. [0027] FIG. 3 shows the calculation of the center of the disturbances as a quick method of checking body travel direction. DETAILED DESCRIPTION [0028] The invention consists of a image acquisition device, such as a camera or holographic imager, which conveys a stream of images to a controller device such as a microcontroller, PGA or microprocessor system, which performs the functions of: [0029] 1) The monitoring of one or more first regions of consecutive images from the stream of images from the image acquisition device looking for activity. [0030] 2) If activity is detected in the first region either, (a) subsequently track the activity within the first region, or (b) generate a second region based on the location of the activity detected within the first region and subsequently track activity within the second region, or (c) subsequent to the detection of the activity within the first region examine a defined second region for activity. [0034] 3) If, with subsequent tracking of activity, it is determined that the activity represent movement of a body in the desired direction, then a record of that body transition is made which contains a copy of the image at the time of qualification, together with any other pertinent information, such as the location and the time. [0035] 4) A means for the storing, retrieval, display and evaluation of the record in isolation and in conjunction with other records is described. [0036] In order to reduce the processing power required to perform the required calculation, and thereby the expense of the processing system, the processor can extracting from the image a small region of interest and evaluate only those pixels in the region of interest. The importance of the processing power limitation can be seen where demonstration systems operating at 600 MHz could successfully calculate in real time at a rate of 10 frames/sec only a line of pixels 600 pixels long while a full VGA representation has over 300,000 pixels . In this discussion when there is reference to pixels it is assumed that this can also refer to groupings of pixels obtained by data compression. For example if the image is rendered in JPEG, rather than rendering the individual pixels from the JPEG representation, the native JPEG average over an 8×8 pixel block can be used. A preferred method for the region selection is the use of one or more lines of pixels or pixel groupings. The lines are easily configured and understood by the user. In the following discussion reference to operation on the preferred regions comprising lines is also to be understood to apply to other regions such as arrays of lines, or of a predefined region that is not comprised of lines. In a region of interest, activity (i.e. motion) can be detected in several ways. The first step is the identification of which pixels are changing. One technique for change detection is to look for the difference of one image compared to a background calculated in a predetermined manned from prior images, with the difference exceeding some predetermined level. A preferred method is to simply use the weighted region Y, U and V differences between one image and the immediately preceding image, and declaring a disturbance if this difference exceeds a predetermined value (which may depend on the remaining values or average values). This avoids propagating disturbances such as sudden lighting changes. A typical webcam-type camera with VGA resolution can easily take 5 or 10 frames per second with sufficient resolution allowing evaluation of the changes in a 100 to 200 millisecond period. While this has been found to be a preferred method of activity detection, the system has also been operated by comparing the current image region to a more persistent background average from previous snaps. This technique of comparing a pixel to a background that is allowed to only change slowly (e.g. by allowing only a fractional change on each snap) is particularly useful when detecting occasional changes such as the opening of a door. In comparing one image's region to the same region in a previous image, differences show the motion of a body, i.e. activity, within the region of interest. The system is compatible with other methods of motion filtering such as edge detection, correlation calculation between images on the lines or second derivative calculation. A combination of motion detection methods can also be used. [0037] The second step is the allocation of the changed pixels into bodies of associated disturbances within the region of interest. The recognition of activity in an region is the recognition of disturbed (i.e. changed) pixels within the region which can be grouped into a body which has movement in a desired direction. We will locate the bodies in an region (demonstrated as a line) in FIG. 1 . We will then show that on two such lines the bodies can be correlated in FIG. 2 . The two lines in FIG. 2 could represent two images of the same region at different times or two spatially related lines. The differences between the correlated bodies then show movement in time between two locations, giving a position and direction of travel, or the distance in space at a given time, giving the position and direction of travel, [0038] FIG. 1 illustrates one method of determining the presence of a body on a line. Here a disturbance at a pixel is found if the absolute value of the Y change plus the UV change between the current image and the previous image exceeds a predetermined value. If a difference is encountered it is taken as the start of a body, and the body is extended over adjacent disturbed pixels. If a region is encountered where there is no disturbance, further checking is continued while incrementing the variable GAPW. If there is a disturbance before GAPW reaches a predetermined limit, the gap is considered to be a slight aberration and the body length is continued. Otherwise the body is considered to have ended and the location along the region is found by subtracting GAPW from the current pixel location. After finishing this examination in FIG. 1 we have a list of the start and end of each body on the line. [0039] If the first regions consist of a single line (function 2a above) then the location along the line of subsequent activity can be tracked. If the image prior to the case where no activity is found on the line shows the activity near one end of the line, it can be assumed that that is the line end from which the body exited. FIG. 2 illustrates how the bodies determined on one line can be tracked against the equivalent bodies on a second line. If the second line (BODYLIST2) is the table of bodies on the previous image of the same region then FIG. 2 would be a means of tracking the body movement within the same region. All bodies in the two lines are compared for overlap with a predetermined allowed separation distance. If the first regions consist of two approximately parallel lines then the analysis in FIG. 1 can associate the bodies on the two lines that are approximately the same distance down the two lines. When such associated bodies had first appeared on one of the lines or appeared last on one line, movement of the body from the body where the line first appeared to the line where the body last appeared can be assumed. This is useful when the camera has an overhead placement and there are multiple bodies crossing the lines. [0040] Often the counting region has background traffic, for example store traffic just behind an entrance. In such cases it is useful to have one line (referred to as a trigger region) which is monitored for the start or finish of activity detected on the region at which time consideration is moved to analyzing activity along a second line. One use of this is to put the trigger line vertically on the door frame where it will see no background traffic, and look for activity on the trigger line. Once the trigger line activity has stopped (with possible delay to allow for the body pausing or momentarily signaling no contrast) then an region inside the door is monitored, possibly looking for no activity indicating the body on the trigger line has left and should not be counted. Another use of the trigger line would be monitoring traffic in a small room with people mulling. Here the trigger line could be placed where the opening of a door would trigger this line and the second line would monitor activity just inside the door. Without the trigger line activity would be frequently detected just inside the door. [0041] Another application of the trigger line is where activity is monitored along the trigger line as described in FIG. 1 and FIG. 2 (where BODYLIST 2 represents the bodies detected in one or more previous images) to detect when and where a body leaves the trigger line. Line 2 can then be dynamically generated from the point where the trigger line was left and further analyzed. In one such example of a second line dynamically generated from the trigger line would be a trigger line across a wide entrance. Bodies can be tracked on this trigger line as described above, and note taken where a body has disappeared from this trigger line. This body is traveling across the trigger line either in a countable direction or in the opposite direction where no count is to be made. To determine this a line or lines can be generated from near the point on the trigger line where the body left the trigger line extending in the countable direction. In practice this has been a “trailer” line scaled to the camera distance with a crossing bar at the end of the trailer bar to catch body travel that was not purely perpendicular to the trailer line. The detection of a disturbance on this dynamically generated second line or lines is then indicative of the body traveling in the countable direction. [0042] Often on line 2 the only information required is the presence or absence of activity showing that the person is present on line 2 (and should be counted) or is not present, and hence was traveling in the direction that is not counted. There have been problems encountered when a body leaves and is immediately followed by another outgoing body which is then present on line 2 so that a simple directional detection on line 2 as will be described next avoids this false count. [0043] If not too many bodies are expected or equivalently line 2 is short, the body centroid of the disturbance can be calculated as shown in FIG. 3 to show the center of disturbances to indicate which end of the line has been exited. Note that in FIG. 3 the DIFFS are accumulated into averaged buckets, or alternatively they could be decimated. This is an optional step that also could have been applied in FIG. 1 to reduce significantly computational time. There are a number of simple calculations, such as shown in FIG. 1 and FIG. 2 , or the calculation of peaks of the correlation coefficient of successive images that also indicate the direction of motion along line 2. An alternative but somewhat equivalent approach is to measure the undisturbed pixels closest to the trigger line and determine if the undisturbed space is increasing (a body tripped the trigger line and is moving away in a countable direction) or is decreasing (indicating a body following the body that tripped the trigger line and should not be counted). [0044] Often there are multiple entrances that are observable from one camera location. In such cases one system can iteratively perform the above evaluations on regions specific to each entrance, and the entrance counts from each evaluation can either be merged or reported as different locations. The use of iteration to investigate movement multiple lines can also be used to investigate the divergence of people within a store or traffic within different regions. [0045] When a body is found to be moving along a direction that is to be counted this is referred to as a countable event. A record of this event is created which includes the image from which the countable event was determined together with all pertinent information, such as the date and time and the location. This record can be as a stand-alone event record or as an entry into a database. The countable event records are made available to users, possibly through a processor-based web server, software and hardware in the computing element having the capability to download to a central server, or commitment to a removable media. If downloaded to a computationally enhanced server, the system described above can be a screener for the server, allowing such filtering as facial recognition or the search for demographic information to be applied to the images in the countable event records to obtain further information to be added to the record. Because of the variables in user firewalls it is advantageous if downloads to remote servers be via tunneling. [0046] While the previous discussion may refer to generalized traffic, or refer to entrances and exits, it should be recognized that the principles of this invention can refer to many types of bodies, e.g. people, cars, or product, and to many types of movement monitoring, e.g. traffic within regions of a store or building, entry to operating rooms, monitoring of entry to restricted regions, etc.

A method and apparatus to monitor and document movement of bodies along or through selected regions is described for the directional counting of such bodies. The reduction of the consideration to selected regions avoids excessive calculation and allows the use of an inexpensive image acquisition and processor. Methods for the determining the direction of movement are described. A record is created for counting events for recording or downloading to a server for further manipulation.

FIELD OF THE INVENTION The invention generally relates to fluid containers, particularly those suited for the storage and dispensing of parenteral solutions and the like. The invention also relates to the attachment of these containers to associated fluid conduits. The invention also generally relates to fluid containers fabricated from materials having low water vapor loss characteristics, as well as the attachment of these containers to conduits fabricated from dissimilar materials. DESCRIPTION OF THE PRIOR ART It is desirable to connect a fluid container to a fluid circuit in a secure and durable manner. This type of connection is particularly desirable when sterile parenteral fluids are involved. It is also desirable to protect solutions stored in containers from the diffusion of water vapor through the container walls, because this can in time lead to a change in the concentration of the stored solution. Protection against water vapor loss is particularly desirable when the stored fluid is a sterile parenteral solution. Formulations of polyvinyl chloride plastic are widely used for parenteral solution containers and the like. However, because polyvinyl chloride plastic has a relatively high water vapor loss characteristic, various substitute plastic formulations have been proposed. In this regard, attention is directed to the following U.S. Patents: Sako et al.--U.S. Pat. No. 3,940,802--Mar. 2, 1976 Grode et al.--U.S. Pat. No. 4,112,989--Sept. 12, 1978 Waage--U.S. Pat. No. 3,942,529--Mar. 9, 1976 Rinfret--U.S. Pat. No. 4,131,200--Dec. 26, 1978 Watt--U.S. Pat. No. 4,183,434--Jan. 15, 1980 Gajewski et al.--U.S. Pat. No. 4,210,686--July 1, 1980 Smith--U.S. Pat. No. 4,222,379--Sept. 16, 1980 Many of the proposed substitutes for polyvinyl chloride plastic, while having lower water vapor loss characteristics, are chemically dissimilar to polyvinyl chloride plastic and, as a result, do not readily and securely bond to polyvinyl chloride plastic tubing by conventional thermal or chemical means. The following pending U.S. Applications, which are assigned to the assignee of the present invention, generally address the problem of interconnecting polyvinyl chloride plastic tubing with fluid containers of dissimilar materials: U.S. application Ser. No. 041,838, filed May 23, 1979, and entitled "TUBING CONNECTION FOR CONCONTAINERS GENERALLY UTILIZING DISSIMILAR MATERIAL". U.S. application Ser. No. 067,068, filed Aug. 15, 1979, and entitled "CONNECTOR MEMBER FOR DISSIMILAR MATERIALS". With the above considerations in mind, it is one of the principal objects of this invention to provide an assembly which serves to interconnect a fluid container with a fluid conduit in a secure and durable manner, and which facilitates the permanent, integral connection of the container with a prearranged fluid circuit, such as that disclosed in pending U.S. application Ser. No. 100,975, filed Dec. 6, 1979 and entitled "MONITOR AND FLUID CIRCUIT ASSEMBLY" (assigned to the assignee of the present invention). It is another principal object of this invention to provide an assembly which facilitates the secure and durable interconnection of a container with a conduit, even though dissimilar materials are utilized. It is still another principal object of this invention to provide an assembly which facilitates the construction of a container having a low water vapor loss characteristic, as well as the interconnection of this container with a fluid conduit fabricated of a polyvinyl chloride plastic material. SUMMARY OF THE INVENTION To achieve these and other objects, the invention provides a port block assembly for interconnecting a fluid container with a fluid circuit. The assembly includes a body portion which has a port and which is operative for attachment to the container with the port in flow communication with the interior of the container. The assembly also includes an insert portion which is engagable within the port of the body portion and which is attachable to a fluid conduit. A secure and durable connection between the container and conduit results. In one embodiment, the insert portion includes, as an attachment thereto, a valve mechanism which normally blocks flow communication through the insert portion. The valve mechanism is manually operative for selectively opening the flow communication. In one embodiment, the fluid container is fabricated of a material which has a relatively low water vapor transmission characteristic and which is not bondable to the polyvinyl chloride plastic material from which the fluid conduit is formed. In this embodiment, the body portion of the port block assembly is fabricated from the same material as the container and is thus directly bondable thereto. On the other hand, the insert portion is fabricated from polyvinyl chloride plastic for direct attachment to the fluid conduit and is adapted for interference fit engagement within the body portion port. The difficulty of effecting a thermal or chemical bond between the two dissimilar materials of the body and insert portions is thus overcome, and a secure, durable interconnection between the dissimilar container and conduit is achieved. The invention also provides a solution container which utilizes the port block assembly as generally described above. In the preferred embodiment, the container includes first wall means, which peripherally encloses a fluid chamber, and second wall means, which is disposed outwardly of the first wall means and peripherally defines an interior area which envelops the fluid chamber. The second wall means includes an opening providing access into this interior area. In this embodiment, the body portion of the port block assembly is engaged in the access opening of the second wall means, and the insert portion is located within the body portion port in flow communication with the enveloped fluid chamber of the first wall means. In this embodiment, the first wall means of the container and the insert portion of the port block assembly are both preferably fabricated from a polyvinyl chloride plastic material, as is the intended fluid conduit. The second wall means of the container is preferably fabricated from a material having a low permeability to water vapor and prevents the loss of water vapor from the interior fluid chamber into the atmosphere. In accordance with the invention, the body portion of the assembly is fabricated from the same material as the second wall means, and the polyvinyl chloride plastic insert portion is engaged in an interference fit within the body portion port to afford the desired interconnection between the container and the polyvinyl chloride plastic conduit. The invention also provides a fluid circuit which includes conduit means defining a predetermined fluid flow path. The circuit also includes a container having an interior fluid chamber and an access opening thereto. The circuit utilizes the port block assembly as heretofore described to permanently and integrally interconnect the container with the conduit means to afford communication between the fluid chamber and the fluid flow path. The conduit means and the preattached containers form a fluid circuit which is substantially closed to the atmosphere. Other features and advantages of the embodiments of the invention will become apparent upon reviewing the following more detailed description, the drawings, and the appended claims. DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view, with parts broken away, of a portion of a fluid circuit which includes a pair of "double wrapped" fluid-filled containers, each of which is integrally connected to the circuit by the use of a port block assembly embodying various of the features of the invention; FIG. 2 is an enlarged and exploded view, with parts broken away, of one of the "double wrapped" containers and associated port block assembly shown in FIG. 1; FIG. 3 is an assembled view, with parts broken away, the "double wrapped" container shown in FIG. 2; FIG. 4 is a top view of the port block assembly which embodies various of the features of the invention; and FIG. 5 is a side view of "single wall" container which includes the port block assembly generally shown in FIGS. 2 and 4 and which, like the "double wrapped" container shown in FIGS. 2 and 3, can be integrally attached to the fluid circuit shown in FIG. 1. Before explaining the embodiments of the invention in detail, it is to be understood that the invention is not limited to its application to the details of construction and the arrangement of components as set forth in the following description or as illustrated in the accompanying drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. Furthermore, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. DESCRIPTION OF THE PREFERRED EMBODIMENT A fluid circuit 10 is shown in FIG. 1. The circuit 10 includes conduit means 12 which defines a prearranged array of fluid flow paths. Such a circuit 10 is particularly well suited for use in environments in which relatively complex or convoluted fluid circuits are involved, and/or in which it is necessary or desirable to protect the interiors of the fluid flow paths from exposure to the atmosphere. For example, the circuit 10 is ideally suited for use in the collection and processing of human blood. The discussion to follow specifically contemplates such use, but the adaptability of the circuit 10 for use in other environments should be appreciated. In the context of human blood collection and processing, the fluid circuit 10 includes a compact, portable module 18, or housing, in which one or more flexible tubes 20 extends. The tubes 20 define an array of paths through which the blood and blood components flow during the processing operation. In the particular embodiment illustrated in FIG. 1, the module 18 is configured to facilitate its mounting on a blood centrifugation device (not shown). Furthermore, portions 22 of the tubes are looped outwardly of the module 12 for operative engagement with peristaltic pump rotors (not shown) carried on the centrifugation device to pump blood and blood components through the tubes 20. A more detailed description of the module 12, its mounting, and the flow of fluids therethrough can be found in now pending U.S. application Ser. No. 100,975, heretofore cited. A pair of fluid-filled containers, designated 14a and b in FIG. 1, are each individually attached to the conduit means 12 by use of a port block assembly 16 which embodies various of the features of the invention. The fluid-filled containers 14a and b thereby form an integral, or preattached, part of the fluid circuit 10. In the environment of human blood collection and processing, one of the integrally attached containers (designated in FIG. 1 as 14a) preferably holds a sterile saline solution. The other one of the integrally attached containers (designated in FIG. 1 as 14b) preferably holds a sterile anticoagulant solution. These sterile solutions are introduced into the fluid paths during the blood processing procedure. As before mentioned, the port block assembly 16 interconnects each container 14a and b with the fluid circuit 10. As can be best seen in FIGS. 2 through 4, the port block assembly 16 generally includes a body portion 24 in which one or more ports 26 are formed. The assembly 16 also includes a separate, generally rigid insert portion 28 for each port 26. Each insert portion 28 includes a bore 30 and is fitted within its associated port 26. The bore 30 thus forms a fluid flow path. Each bore 30 includes an end 32 and an end 34 which extends outwardly beyond the body portion 24 for connection with an end of tubing 20. The number of ports 26 and associated inserts 28 can be preselected according to the number of fluid connections required. Furthermore, as is shown in FIG. 2, the assembly 16 includes valve means 38 which may be attached to the end 32 of a selected insert portion or portions 28, as desired. The valve means 28 normally blocks flow communication through the bore 30 of the selected insert portion 28 and is operative in response to manual manipulation for opening the flow communication through the selected insert portion 28. The valve means 38 itself may be variously constructed. However, in the illustrated embodiment (see FIG. 2), the valve means 38 includes a generally rigid tubular member or cannula 40 which is attached, such as by solvent bonding, to the inner end 32 of the selected insert portion 28. The cannula 40 includes a frangible end wall 42 disposed therein, which normally blocks flow communication through the cannula 40 and, thus, through the selected insert portion 28 itself. In this arrangement, the valve means 38 includes means in the form of a rigid member 44 which extends outwardly from the frangible wall 42. Manual manipulation (generally shown by an arrow in FIG. 2) serves to break the rigid member 44 away and fracture the frangible wall 42 (as shown in phantom lines in FIG. 2). This operation opens flow communication through the cannula 40 and attached insert portion 28. The port block assembly 16 lends itself to use with various types of fluid containers. Two embodiments are shown in the drawings, both of which are equally well suited for interconnection with the circuit 10. Containers 14a and b shown in FIGS. 1 through 3 each incorporates one such embodiment, and the container 46 shown in FIG. 5 incorporates the other. Reference is first made to the container embodiment shown in FIG. 5. Here, the container 46 includes wall means 48 which peripherally encloses an interior fluid chamber 50 having an access opening 52 thereto. The wall means 48 takes the form of two overlapping sheets 54 of plastic material, the peripheral edges of which are joined, such as by solvent, heat, or RF sealing, to form a flexible bag in which a fluid solution can be stored. In this arrangement, the body portion 24 of the port block assembly 16 is fabricated of a plastic material which is similar to the sheet material and which is thus directly bondable to the peripheral edges of the access opening 52 by conventional methods, such as solvent, R.F., or heat bonding. Each insert portion 28 is fabricated of a plastic material which is directly bondable, such as by solvent bonding, to the material of which the associated fluid tubing 20 is made. The plastic materials utilized for the container 46, the port block assembly 16, and tubing 20 can vary according to the intended use of the circuit 10. In the context of the intended use of the fluid circuit 10 in FIG. 1, medical grade polyvinyl chloride plastic formulations (hereafter identified simply as PVC) can be utilized both for the sheet material of the container 46 as well as tubes 20 of the associated circuit 10, because PVC exhibits many characteristics well suited for the storage of parenteral solutions, as well as contact with human blood. In this arrangement, both the body portion 24 and the insert portions 28 of the port block assembly 16 are likewise preferably formed of PVC, and each insert portion 28 may be attached by heat or solvent bonding within the associated port 26. However, since it is recognized that PVC exhibits a high tendency to permit the diffusion of water vapor, which can in time lead to a change in the concentration of the stored solution, the wall means 48 of the container 46 can be constructed of overlapping sheets of a non-PVC material having a lower permeability to water vapor; for example, a polyolefin material, such as polyethylene or polypropylene, or copolymers thereof. In this arrangement, the body portion 24 of the port block assembly 16 is preferably fabricated from the same or similar polyolefin material and can be bonded directly to the wall means 48 by conventional methods, such as solvent or heat sealing. However, since PVC tubing still finds widespread use, the insert portions 28 are preferably fabricated from rigid, nonplasticized PVC, although acrylic or polycarbonate materials could also be used. Recognizing that PVC is dissimilar to and thus does not directly bond to propylene materials, the rigid insert portions 28 are constructed for a friction or interference fit within the ports 26 of the body portion 24, thereby eliminating the need for a thermal or chemical bond. In the container 46 shown in FIG. 5, the tubing 20 associated with the fluid circuit 10 (which tubing is shown in phantom lines in FIG. 5) is secured to one of the insert portions 28 (shown as the left-hand side insert portion in FIG. 5). A cannula 40 and breakaway member 44 are attached to the same insert portion 28, so that fluids stored in the chamber 50 of the container 46 can be selectively dispensed, via the tubing 20, into the fluid circuit 10. As can be seen in FIG. 5, the breakaway member 44 extends partially into the fluid chamber 58 to facilitate manual manipulation to fracture the wall 42, after which the separated member 44 is freed into the chamber 50. In this construction, the cannula 40 and breakaway member 44 are preferably made of PVC to permit a direct solvent or heat bond to the inner end 32 of the PVC insert portion 28. In FIG. 5, another insert portion 20 (shown as the right-hand side insert portion in FIG. 5) includes a section 78 of flexible PVC tubing solvent bonded within the bore 30. The tubing section 78 terminates outwardly of the outer end 34 of the insert portion 28 and can be coupled to a source of sterilizing gas, such as ethylene oxide, to sterilize the interior fluid chamber 50. Radiation sterilization or autoclaving can also be used, depending upon the particular material from which the container 56 is fabricated. After sterilization, the same tubing section 78 can be coupled, utilizing known sterile transfer techniques, to a source of sterile fluid to conduct the sterile fluid into the now sterilized container chamber 50. The tubing section 78 is thereafter crimped or heat sealed closed. When it is subsequently necessary to introduce the sterile fluid into the fluid circuit 10, the breakaway member 44 associated with the other insert portion 28 can be manipulated to open a fluid path leading from the chamber 50. Reference is now made to the container embodiment shown in FIGS. 1 through 3, in which container 14b is specifically shown. Unlike the single wall construction of container 46, the container 14b utilizes a double wall, or "double wrapped", construction to minimize water vapor loss from the stored solution. It should be appreciated that container 14a shares generally the same identical "double wrapped" construction of container 14b. In this embodiment, the container 14b includes the first wall means 56 which peripherally encloses a fluid chamber 58 in which the solution is stored. As illustrated, the first wall means 56 takes the form of overlapping sheets 57 and 59 of material, preferably PVC, the peripheral edges of which are sealed to form a flexible bag 72 in which the fluid chamber 58 is located. Ports 60 are integrally formed in the bag 72 to provide communication with the fluid chamber 58. The container 14b also includes second wall means 62 which is disposed outwardly of the first wall means 56 and which peripherally defines an interior area 64 enveloping the bag 72 and, hence, the fluid chamber 58 itself. An opening 66 is provided for access into the interior area 64. The second wall means 62 preferably takes the form of overlapping sheets 63 and 65 of material having a low vapor transmission characteristic, preferably polyethylene, to define an overwrap pouch 74 which serves as a vapor barrier surrounding the inner PVC bag 72. In this arrangement, the body portion 24 of the port block assembly 16 is preferably fabricated of a polyethylene type material, or a chemically similar material, which is bondable directly to the periphery of the access opening 66 of the overwrap pouch 74 (see FIG. 3), such as by solvent or heat sealing methods. On the other hand, the insert portion 28 of the port block assembly 16 is preferably formulated of rigid, nonplasticized PVC for direct solvent bonding to PVC tubing, although acrylic or polycarbonate materials could also be used. Because of the dissimilar plastics utilized, the rigid PVC insert portion 28 is sized so as to be engagable in an interference or friction fit within the port 26 of the polyethylene body portion 24. In this embodiment, and as best seen in FIG. 2, to effect communication between the insert portion 28 and the fluid chamber 58 of the PVC bag 72, the insert portion 28 includes conduit means 76 which extends within the interior area 64 of the overwrap pouch 74 between the inner end 32 of the associated insert portion 28 and a selected port 60 of the inner bag 72. The conduit means 76 may be variously constructed according to the particular use contemplated. In one embodiment, the conduit means 76 can take the form of the PVC cannula 40, heretofore generally described, which is solvent bonded to the end 32 of a selected insert portion 28 (the left hand insert portion 28 in FIGS. 2 and 3), as well as to an adjacent one of the bag ports 60. If a selectively operable valve mechanism is also desirable (which is usually the case), the cannula 40 can be provided with the heretofore described frangible wall 42 and breakaway member 44. As can be seen in FIG. 3, and like the FIG. 5 embodiment, the breakaway member 44 extends partially into the fluid chamber 58 to facilitate manual manipulation to fracture the wall 42, after which the separated member 44 is freed into the chamber 58. Also like the FIG. 5 embodiment, the insert portion 28 to which the breakaway member 44 is attached is connected to the tubing 20 (shown in phantom lines in FIG. 3) associated with the fluid circuit 10. In this regard, it should be noted that additional insert portions 28 with associated breakaway members 44 can be utilized, if desired, such as the pair associated with container 14a (see FIG. 1), depending upon the number of tubing connections desired. Also as shown in FIG. 1, drip chambers 86 and roller clamps 88 can be employed downstream of the containers 14a and b to further control the fluid flow from the containers 14a and b into and through the circuit 10. In another embodiment, the conduit means 76 can take the form of the section 78 of flexible PVC tubing solvent bonded to a selected one of the bag ports, (see FIG. 2), extending therefrom through the interior area 64 of the pouch 74, and bonded within the bore 30 of another insert portion 28 (shown as the right hand insert portion in FIG. 3). As in the FIG. 5 embodiment, the tubing section 78 terminates outwardly of the outer end 34 of the insert portion 28 and can be utilized, using known sterile transfer techniques, to conduct a sterilizing gas and thence a sterile solution into the inner bag 72, after which the tubing section 78 can be crimped or heat sealed closed. Thus, just as in the FIG. 5 embodiment, when it is subsequently necessary to utilize the sterile solution in the chamber 58, the breakaway member 44 associated with another insert portion 28 can be manipulated to open a fluid path leading from the chamber 58. Furthermore, in the embodiment shown in FIG. 2, the port block assembly 16 includes an additional port 26 and associated insert portion 28 (shown as the left hand insert portion in FIGS. 2 and 3). A section 82 of flexible tubing is bonded to the bore of this insert portion 28 and communicates only with the interior area 64 of the overwrap pouch 74. The tubing section 82 can be utilized to transfer a sterilizing gas into the interior area 74. Preferably, sterile cotton or the like is inserted into the tubing section 82 prior to sterilization to act as a sterile barrier to maintain the interior sterility of the interior area 74 surrounding the solution bag 72. The arrangement just described permits the entire fluid circuit 10, including the integrally attached containers 14a and b, to be preassembled, presterilized, and prefilled with sterile solutions. Preferably, as is best shown in FIG. 4, in each of the above described embodiments, the body portion 24 of the port block assembly 16 has a generally eliptical shape and includes gradually tapering end portions 84. This contoured shape facilitates a smooth and continuous bond between the periphery of the body portion 24 and the periphery of the access opening 52 of the container 46 (in the FIG. 5 embodiment), and between the periphery of the body portion 24 and the periphery of the access opening 66 of the overwrap pouch 74 (in the FIGS. 2 and 3 embodiment). It should be appreciated that the port block assembly 16 heretofore described provides a secure and durable connection between a container and a fluid conduit, a connection which is capable of withstanding rough handling during shipment, storage, and use. The connection thus minimizes the chance of leaks or accidental ruptures. This durability is particularly important when sterile fluids are involved. It should also be appreciated that the port block assembly 16 permits the construction and preattachment of prefilled, sterile solution containers to fluid circuits in a permanent manner. The assembly 16 thus significantly facilitates the creation of essentially "closed" fluid systems. It also significantly facilitates the construction of a container having a low water vapor loss characteristic and the interconnection of this container with a fluid conduit fabricated of a dissimilar material. Finally it should be appreciated that various changes and modifications can be made without departing from the spirit of the invention or from the scope of the appended claims.

A port block assembly for interconnecting a fluid container with a fluid conduit includes a body which has a port and which is attachable to the container with the port in flow communication with the container interior. The assembly also includes a rigid, tubular insert which is engageable within the body port and to which the fluid conduit can be attached. A secure and rugged interconnection between the container and the conduit results. When the container and conduit are fabricated from dissimilar materials, the body of the assembly is fabricated from the same materal as the container, and the associated insert is fabricated from the same material as the conduit and adapted for an interference or friction fit within the body port. The same secure and rugged interconnection between the container and conduit is achieved, despite the presence of dissimilar materials.

BACKGROUND [0001] Olefins, particularly ethylene and propylene, are important chemical feedstocks. Typically they are found in nature or are produced as primary products or byproducts in mixtures that contain saturated hydrocarbons and other components. Before the raw olefins can be used, they usually must be purified from these mixtures. Numerous difficulties have been experienced in this type of separation. Due to their similar relative volatilities, energy-intensive, capital-intensive, multi-trayed distillation columns typically have been used to purify light olefins. [0002] An example of a prior art distillation column for the separation of propylene and propane is illustrated in FIG. 1 . In an exemplary method of operation, a raw feedstock of Refinery Grade Propylene (RGP) comprising 70% propylene and 30% propane is introduced to distillation column 105 along feed pipe or pipes 100 . Distillation column 105 generally comprises multiple trays, or levels (not shown). In an embodiment, distillation column 105 comprises 135 trays. Operation of a distillation column 105 is primarily determined by a combination of the number of trays and the reflux ratio. In general, the more trays in a distillation column 105 , the greater the separation at a constant reflux ratio, but also the greater the capital cost. Conversely, fewer trays can be used if reflux is increased, but operating cost also increases. In the distillation column 105 , the lighter components tend to rise and the heavier components tend to sink. The lighter components are extracted along piping 135 and directed to condenser 145 for cooling. Some of the condensed lighter components may be injected back into distillation column 105 . Some of the condensed lighter components may be utilized as a propylene product stream 130 , such as Commercial Grade Propylene (CGP nominally 93% propylene). [0003] A second stream comprising propane and other heavier components may be extracted from column 105 along piping 115 , re-vaporized in vaporizer 125 , and injected back into column 105 along piping 110 . Some of the second stream may be utilized as a propane product 120 having typically greater than 95% propane. [0004] Column 105 is merely one example of a propylene and propane distillation column. One of ordinary skill in the art would readily understand that many variations are possible. [0005] Typical results from a single distillation column, with a 70% propylene feed, produces a propylene product of 93% purity and a propane product of 95% purity. Accordingly, an improved system would produce results at least as good as a typical prior art distillation column. [0006] The field of art has proposed the use a membrane-based system. U.S. Pat. No. 3,758,603 and U.S. Pat. No. 3,864,418 in the names of Robert D. Hughes and Edward F. Steigelmann describe membranes used in conjunction with metal complexing techniques to facilitate the separation of ethylene from ethane and methane. Similar metal complex and membrane hybrid processes, called facilitated transport membranes, have been described in U.S. Pat. No. 4,060,566 in the name of Robert L. Yahnke and in U.S. Pat. No. 4,614,524 in the name of Menahem A. Kraus. Further membranes have been considered for the separation of olefins from paraffins as an alternative to distillation. However, the separation is difficult largely because of the similar molecular sizes and condensability of the components desired to be separated. The membrane must operate in a hydrocarbon environment under conditions of high pressure and temperature, often resulting in plasticization that may result in a loss of selectivity and/or permeation rate. Such harsh conditions tend to adversely affect the durability and stability of the separation performance of many membrane materials. A membrane system with sufficiently high olefin/paraffin selectivity, high productivity, and sufficient durability in long-term contact with hydrocarbon streams under high pressure and temperature is highly desired. [0007] The art is replete with processes said to fabricate membranes possessing both high selectivity and high fluxes. Without sufficiently high fluxes the required membrane areas required would be so large as to make the technique uneconomical. It is now well known that numerous polymer membranes are much more permeable to polar gases (examples include H 2 O, CO 2 , H 2 S, and SO 2 ) than to nonpolar gases (N 2 , O 2 , and CH 4 ), and that gases of small molecular size (He, H 2 ) permeate more readily through polymer membranes than large molecules (CH 4 , C 2 H 6 ). [0008] However, even considering these difficulties, utilization of membrane separation has taken an important place in chemical technology for use in a broad range of applications. Gas separation has become a major industrial application of membrane technology in the last 15 years. Membrane based technology for the production of nitrogen from air, removal of carbon dioxide from natural gas, and purification of hydrogen now occupy significant shares of the markets for these processes. [0009] Membrane materials and systems for separating olefinic hydrocarbons from a mixture of olefinic and saturated hydrocarbons have been reported, but are not easily or economically fabricated into membranes that offer the unique combination of high selectivity and durability under industrial process conditions to provide economic viability. [0010] For example, several inorganic and polymer/inorganic membrane materials with good propylene/propane selectivity have been studied. However, fabrication of these membranes into practical industrial membranes has proven difficult. Likewise, liquid facilitated-transport membranes have been demonstrated to have attractive separation performance in the lab, but have been difficult to scale up, and have exhibited declining performance in environments typical of an industrial propylene/propane stream. [0011] Solid polymer-electrolyte facilitated-transport membranes have shown to be capable of fabrication into more stable thin film membranes for ethylene/ethane separation. See Ingo Pinnau and L. G. Toy, Solid polymer electrolyte composite membranes for olefin/paraffin separation, J. Membrane Science, 184 (2001) 39-48. However, these membranes are severely limited by their chemical stability in the olefin/paraffin industrial environment. [0012] Carbon hollow-fiber membranes have shown promise in laboratory tests (“Propylene/Propane Separation”, Product Information from Carbon Membranes, Ltd., Israel), but are vulnerable to degradation caused by condensable organics or water present in industrial streams. Moreover, carbon membranes are brittle and difficult to form into membrane modules of commercial relevance. [0013] Membranes based on rubbery polymers typically have olefin/paraffin selectivity too low for an economically useful separation. For example, Tanaka et al. report that the single-gas propylene/propane selectivity is only 1.7 for a polybutadiene membrane at 50° C. (K. Tanaka, A. Taguchi, Jianquiang Hao, H. Kita, K. Okamoto, J. Membrane Science 121 (1996) 197-207) and Ito and Hwang report a propylene/propane selectivity only slightly over 1.0 in silicone rubber at 40° C. (Akira Ito and Sun-Tak Hwang, J. Applied Polymer Science, 38 (1989) 483-490). [0014] Membranes based on glassy polymers have the potential for providing usefully high olefin/paraffin selectivity because of the preferential diffusivity of the olefin, which has a smaller molecular size than the paraffin. [0015] Membrane films of poly(2,6-dimethyl-1,4-phenylene oxide) exhibited pure gas propylene/propane selectivity of 9.1 (Ito and Hwang, Ibid.) Higher selectivity has been reported by Ilinitch et al. (J. Membrane Science 98 (1995) 287-290, J. Membrane Science 82 (1993) 149-155, and J. Membrane Science 66 (1992) 1-8). However, the membrane exhibited plasticization, most likely due to the presence of hydrocarbons. [0016] Polyimide membranes have been studied extensively for the separation of gases. An article by Lee and Hwang discloses a hollow fiber membrane of a polyimide that exhibits a mixed-gas propylene/propane selectivity in the range of 5-8 with low feed pressure (2-4 bar). Kwang-Rae Lee and Sun-Tak Hwang, Separation of propylene and propane by polyimide hollow-fiber membrane module, J. Membrane Science 73 (1992) 37-45. [0017] Krol et al. report a hollow fiber membrane of a polyimide composed of biphenyltetracarboxylic dianhydride and diaminophenylindane which exhibited a pure-gas propylene/propane selectivity of 12. J. J. Krol, M. Boerrigter, G. H. Koops, Polyimide hollow fiber gas separation membranes: preparation and the suppression of plasticization in propane/propylene environments, J. Membrane Science. 184 (2001) 275-286. However, this membrane was plasticized at even low pressures. [0018] Matrimid and P84/Matrimid blend hollow fiber membranes have been shown to plasticize and lose selectivity when exposed to a propane/propylene stream. T. Visser and M. Wessling, Auto and Mutual Plasticization In Single and Mixed Gas C3 Transport Through Matrimid-Based Hollow Fiber Membranes, J. Membrane Science, 312 (2008) pp. 84-96. [0019] Many of these prior art membrane-based techniques of propane/propylene separation utilize a pervaporation mode (liquid feed, gaseous permeate) or gas separation mode (gaseous feed, gaseous permeate). In the pervaporation mode of operation, the liquid feed is “evaporated” to the permeate stream. The latent heat of vaporization is large and a large temperature decrease accompanies the separation. Pervaporation based separation has similarities to propane refrigeration. The high pressure feed permeates the membrane to low pressure. This process is similar to the expansion of propane across an expansion valve in a propylene refrigeration system, resulting in cooling of the permeate stream. [0020] A convenient mathematical method of describing pervaporation is to divide the separation into two steps. The first is evaporation of the feed liquid to form a hypothetical saturated vapor phase on the feed side of the membrane. The second is permeation of this vapor through the membrane to the low pressure permeate side of the membrane. Although no evaporation actually takes place on the feed side of the membrane during pervaporation, this approach is mathematically simple and is thermodynamically equivalent to the physical process. [0021] In pervaporation, transmembrane permeation is typically induced by maintaining the pressure on the permeate side lower than the vapor pressure of the feed liquid. The permeate side pressure can be reduced, for example, by drawing a vacuum on the permeate side of the membrane, by sweeping the permeate side to continuously remove permeating vapor, or by cooling the permeate vapor stream to induce condensation. The feed may also be heated to raise the vapor pressure on the feed side or to at least partially compensate for the temperature drop on permeation. [0022] Certain issues accompany the use of pervaporation, namely, and typically regarded as most important, the temperature decrease causes membrane productivity to decrease and further increase membrane selectivity. This is an inherent problem for pervaporation. It is very difficult to supply sufficient heat at the correct location (face of the membrane) to maintain constant temperature. As a result, productivity decreases exponentially and the number of modules necessary to achieve a desired productivity becomes unacceptably large. Further, the large temperature drop of the feed to the membrane due to the pressure drop often condenses the feed. [0023] At least one prior art patent has identified that temperature has an effect on membrane performance. U.S. Pat. No. 5,679,133 discloses a glassy polymer membrane that is operated at temperatures of less than about 5° C. for separation of gas components. The patent claims a permeation method comprising contacting a first side of a gas separation membrane having a glassy polymer discriminating layer or region with a gas mixture. The polymer cellulose triacetate is expressly excluded. A difference in chemical potential is maintained from the first side of the membrane to a second side of the membrane. At a minimum, one component of the gas mixture relative to a second component selectively permeates from the first side of the membrane through the membrane to the second side of the membrane. The gas mixture contacts the membrane at a temperature of 5° C. or lower. The membrane having a glassy region is selected so that, when using a mixture of 80 mole percent nitrogen and 20 mole percent oxygen as a feed at 30° C. with a pressure of 30 psia on the first side of the membrane and a vacuum of less than 1 mm Hg on the second side of the membrane, the permeability of oxygen in barrers is less than 2000. This patent illustrated that temperatures below ambient could be utilized in permeation procedures. [0024] U.S. Pat. App. Pub. No. 2004/0000513 discloses a plurality of membrane modules disposed in a first product group, a second product group, and optionally one or more intermediate groups used for simultaneous recovery of a very pure permeate product and a desired non-permeate product from a mixture containing organic compounds. Examples of propylene/propane separation are given as simulated by a computer model. The preferred embodiment is a system of three membranes with propylene selectivity over propane. The embodiments disclosed pump feed stock (about 70% propylene/30% propane) in liquid form to a vaporizer and then to a first membrane. The permeate flows through, is compressed, cooled to 200° F. and passed through a second membrane. The permeate is collected as a stream comprising greater than 95% propylene. The non-permeate from the first membrane is passed to a third membrane. Permeate from the third membrane is compressed and passed back through the second membrane. Non-permeate from the third membrane is collected as a propane product. [0025] U.S. Pat. No. 6,986,802 discloses a membrane device comprising multiple perm-selective membranes that are capable of effecting separation of a mixture of two or more compounds in a feed stock which when subjected to appropriately altered conditions of temperature and/or pressure exhibit a bubble point. The enthalpy of the feed stock is adjusted by a heat exchanger. Membrane Efficiency Index of the non-permeate fluid, when withdrawn, is within a range from about 0.5 to about 1.5. The Membrane Efficiency Index is defined as a ratio of the difference between the specific enthalpy of the feed stream entering the membrane device and specific enthalpy of the non-permeate fluid effluent to the difference between the specific enthalpy of the feed stream and the bubble point specific enthalpy of the non-permeate fluid at the non-permeate product pressure and composition. At an MEI of one, the non-permeate is disclosed as being a liquid at its bubblepoint. [0026] U.S. Pat. No. 7,070,694 discloses an apparatus comprising a fractional distillation column and one or more membrane devices utilizing solid perm-selective membranes. The processes are stated as capable of use in simultaneous recovery of a very pure permeate product, a desired non-permeate stream, and one or more distillate products from a fluid mixture containing at least two compounds of different boiling point temperatures. The patent discloses that the cooling effect produced by a membrane when a low pressure permeate is produced from a high pressure feed stock is due to the Joule-Thompson effect. The patent further expresses the need for the incorporation of heat integrated membrane apparatuses with pressure driven membrane separations. [0027] However, these various prior art approaches require excessive capital costs and a multitude of membrane modules. [0028] U.S. Pat. App. Pub. No. 2008/0167512 improves upon the cited prior art. The '512 publication discloses membrane-based systems and methods for separation of propylene and propane that overcome certain issues associated with prior devices and take advantage of a temperature drop across the associated separation membrane. However, the systems and methods still require use of a recycle compressor, which has an associated capital cost as well as operating cost component. [0029] Accordingly, there is a need in the art field for an improved membrane and/or membrane system for the separation of olefins and paraffins that uses fewer membrane modules and requires less capital and operating cost. SUMMARY [0030] Disclosed is a process for the membrane-based separation of a mixture of close-boiling hydrocarbon components. A feed stream comprising the mixture of close-boiling hydrocarbon components is fed to a first membrane stage at a temperature and a pressure above a critical point of the mixture. A first permeate stream and a first non-permeate stream are extracted from the first membrane stage. The process may include one or more of the following aspects: cooling the first permeate stream to produce a liquid product. the feed stream and the first non-permeate stream each having a viscosity and the ratio of the viscosity of the first non-permeate stream to that of the feed stream being less than 5. the feed stream and the first non-permeate stream each having a density and the ratio of the density of the first non-permeate stream to that of the feed stream being less than 5. the feed stream comprising a mixture of propane and propylene. the first membrane stage having a selectivity for propylene over propane of at least 5.0. the first membrane stage having a selectivity for propylene over propane of at least 6.5. the pressure of the feed stream being 700 psi or higher. the pressure of the feed stream ranging from about 900 psi to about 1100 psi. the temperature of the feed stream being 96° C. or higher. feeding the first non-permeate stream to a second membrane stage at a temperature and pressure above the critical point of the first non-permeate stream, extracting a second non-permeate stream, extracting a second permeate stream, and combining the second permeate stream with the feed stream. the second membrane stage having a selectivity for propylene over propane of at least 3.0. the second membrane stage having a selectivity for propylene over propane of at least 5.0. the second non-permeate stream being collected as a liquid or as a two-phase gas/liquid stream having a purity of at least about 95% propane. [0044] Also disclosed is a system for the membrane-based separation of a mixture of close boiling hydrocarbon components. In the system, a feed stream comprising a mixture of close boiling hydrocarbon components is fed to the inlet of a pump. The pump is adapted and configured to pressurize the feed stream to a pressure above a critical pressure of the mixture. The pump's outlet is in fluid communication with the inlet of a first evaporator. The first evaporator is adapted and configured to raise the feed stream's temperature to a temperature above the critical temperature of the mixture. The first evaporator's outlet is in fluid communication with the feed port of the first membrane stage. The first membrane stage further comprises a permeate port and a non-permeate port. The first membrane stage exhibits a selectivity for propylene over propane of at least 6.5. The first membrane stage's non-permeate port is in fluid communication with the feed port of the second membrane stage. The second membrane stage further comprises a permeate port and a non-permeate port. The second membrane stage exhibits a selectivity for propylene over propane of at least 3.0. [0045] The system may further include a second evaporator having an inlet and outlet. The inlet of the second evaporator may be in fluid communication with the non-permeate port of the first membrane stage and the outlet of the second evaporator may be in fluid communication with the feed port of the second membrane stage. The second evaporator is adapted and configured to raise a temperature of a non-permeate stream from the first membrane stage to a temperature above a critical temperature of the non-permeate stream. BRIEF DESCRIPTION OF THE FIGURES [0046] For a further understanding of the nature and objects of the disclosed systems and methods, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein: [0047] FIG. 1 is a flow diagram showing a prior art distillation column for the separation of propylene and propane. [0048] FIG. 2 is a flow diagram showing an embodiment of the current system and method using a membrane separation approach applied to a propylene/propane separation. [0049] FIG. 3 is a flow diagram showing an alternate embodiment of the current system and method applied to a propylene/propane separation. [0050] FIG. 4 is a flow diagram showing a second alternate embodiment of the current system and method applied to a propylene/propane separation. DETAILED DESCRIPTION [0051] The following definitions and explanations are meant and intended to be controlling in any future construction unless clearly and unambiguously modified in the following Description or when application of the meaning renders any construction meaningless or essentially meaningless. In cases where the construction of the term would render it meaningless or essentially meaningless, the definition should be taken from Webster's Dictionary, 3rd Edition. Definitions and/or interpretations should not be incorporated from other patent applications, patents, or publications, related or not, unless specifically stated in this specification or if the incorporation is necessary for maintaining validity. [0052] As used herein, a “fluid” is a continuous, amorphous substance whose molecules move freely past one another and that has the tendency to assume the shape of its container, for example, a liquid or a gas. [0053] As used herein, “membrane apparatus” means and refers to flat sheet membranes, spiral wound flat sheet membranes, tubular tube membranes, hollow fiber membranes, and/or other membranes commonly used in industry. [0054] As used herein, “evaporator” means and refers to a heater or an evaporator. In other words, the evaporators utilized herein may be used to raise the temperature and/or change the phase of the stream being processed from liquid to gas or supercritical. [0055] As used herein, “condenser” means and refers to a cooler or a condenser. In other words, the condensers utilized herein may be used to reduce the temperature and/or change the phase of the stream being processed from gas to liquid. [0056] The present disclosure has wide applicability across the art field for systems and methods for the separation of streams containing a mixture of close-boiling hydrocarbon components. The system may operate with either counter current or cross flow membrane bundles. The method relates primarily to a membrane-based system for the separation of streams containing a mixture of close-boiling components that are condensable at ambient conditions by utilizing a feed fluid in its supercritical state. [0057] The details herein were discovered when improving upon the two step process disclosed in U.S. Pat. App. Pub. No. 2008/0167512 by obviating the need for the recycle compressor. Operating the process at a temperature and pressure such that the feed stream fed to the membranes is above the critical point of the feed stream enables the permeate/low pressure side of the membrane to be set at conditions such that the permeate gas phase may be condensed to a liquid by merely lowering the temperature. The resulting liquid permeate may either be available for downstream processing or recycled back to the membrane feed without the need for additional compression. Operation at pressures and temperatures above the critical point also ensures a continuum of densities and viscosities and as a result there are no sharp phase demarcations within the membrane module. [0058] The disclosure therefore provides a method of separating streams containing close-boiling hydrocarbon mixtures, including, but not limited to, mixtures of ethane and ethylene; propane and propene; 1-butene and butane; and 1-butene, butane, and propane. For the purposes of this application, close-boiling hydrocarbon mixtures are defined as mixtures that contain two or more hydrocarbon compounds with at least one of the compounds having a boiling point close to that of at least a second of the compounds at the pressure at which the disclosed system is operated. Close boiling points are usually within about 45° F. (25° C.) or less, preferably within about 27° F. (15° C.) or less, or more preferably within about 9° F. (5° C.) or less. [0059] The disclosure further provides a method of separating nonideal organic streams. For purposes of this application, nonideality is defined by the inability of the ideal gas law to describe the PVT (pressure volume temperature) behavior of the gas. Non ideality for organic gases increases with molecular weight: methane is more ideal than ethane, ethane is more ideal than propane, propane is more ideal than butane, and the like. In most cases, membrane-based separation of nonideal organic gases leads to a temperature decrease on separation. The temperature change increases with increasing non-ideality of the stream. The temperature change arises due to the reduction in pressure experienced by the permeated gas from the initial feed pressure to the final permeate pressure. This temperature change can be approximated by a Joule-Thompson expansion (dT/dP)H. [0060] In general, the disclosed system comprises, at a minimum, a membrane apparatus, a pump, and an evaporator. A supercritical feed containing a mixture of close-boiling compounds is introduced into the disclosed system. [0061] Many of the negative aspects of membrane-based separation of a nonideal fluid stream are minimized in the present disclosure. In the disclosed process, the feed is initially pumped or compressed to a pressure above the critical pressure of the mixture. The pressurized feed stream is then heated in a vaporizer to a temperature higher than the critical temperature of the feed stream. Vaporization of the stream after pressurization reduces the heat required for vaporization relative to that for vaporization prior to pressurization. This is due to the fact that the heat of vaporization decreases with increasing pressure. Pressurization of the feed has additional benefits. Higher pressure reduces total membrane count (i.e., the number of membranes required). Higher pressure increases the pressure-ratio (i.e., feed pressure to the membrane divided by permeate pressure from the membrane). Higher pressure ratio improves separation performance, in various embodiments. Preferably, the pressure difference between the permeate stream and the feed stream is less than about 2,000 psig, more preferably less than about 1,500 psig, and even more preferably less than about 1,300 psig. [0062] The final pressure and temperature of the feed mixture are selected so as to place the feed mixture into its supercritical region, and preferably well into its supercritical region. As a result, the supercritical mixture exhibits properties of both a gas and a liquid. It exhibits the diffusivity of a gas and the solvent properties of a liquid. Initial test results for supercritical mixtures of propane and propylene indicate that the mixture permeates through the membrane like a gas. The supercritical mixture does not exhibit surface tension because the liquid/gas phase boundary no longer exists. Therefore, although the non-permeate or residue stream may exhibit a temperature below its critical temperature, thereby technically forming a liquid, the pressure of the non-permeate remains above its critical pressure, which results in a slight density and viscosity difference between the supercritical feed and the remaining non-permeate stream. In other words, it is believed that utilizing a supercritical feed stream benefits both the membrane and process because the viscosities and densities of the feed and non-permeate streams remain close. To further benefit the membrane and process, the ratio of the viscosity of the non-permeate stream to that of the feed stream should preferably be less than 5, and more preferably less than 2. Additionally, the ratio of the density of the non-permeate stream to that of the feed stream is preferably less than 5, and more preferably less than 3. [0063] Table 1 lists the critical temperature and critical pressure above which the specific exemplary and non-limiting mixtures of close-boiling compounds A, B, and C must be raised to be placed into the supercritical phase, as well as the density and viscosity of the mixture at that temperature and pressure. One of ordinary skill in the art would be capable of calculating the critical temperature and pressure of other mixtures that may also be separated according to the disclosed method. [0000] TABLE 1 Temp Press Density Viscosity % (v/v) A % (v/v) B % (v/v) C (° C.) (psig) (g/cm 3 ) (Cp) 50% Ethylene 50% Ethane 0% 21 722 0.1 0.02 20% Ethylene 80% Ethane 0% 28 709 0.1 0.02 90% Ethylene 10% Ethane 0% 12 719 0.1 0.02 81% Propylene 19% Propane 0% 93 649 0.1 0.02 60% Propylene 40% Propane 0% 93 636 0.1 0.02 20% Propylene 80% Propane 0% 95 613 0.1 0.02 5% Propylene 95% Propane 0% 96 604 0.1 0.02 10% Propylene 80% 1-Butene 10% Butane 142 584 0.2 0.03 10% Propylene 80% t2Butane 10% Butane 149 582 0.2 0.03 50% 1-Butene 50% Butane 0% 149 571 0.2 0.03 10% 1-Butene 80% Butane 10% Isobutane 150 546 0.1 0.02 10% 1-Butene 80% C2 Butene 10% Isobutane 158 596 0.2 0.03 30% 1-Butene 60% Butane 10% Propane 146 574 0.2 0.02 [0064] Raising the feed pressure of the mixture above and into the supercritical region significantly mitigates concerns of phase change as the mixture undergoes changes in composition, temperature, and pressure as it is emerges as the non-permeate stream. In addition, raising the permeate pressure provides additional advantages. For example, the permeate stream may undergo a phase change from gas to liquid with only modest cooling. Therefore, the compressors 365 and 395 disclosed in FIG. 3 and 465 in FIG. 4 of U.S. Pat. App. No. 2008/0167512 are not needed. Also the pressure of the permeate stream remains low enough to provide a reasonable pressure ratio across the membrane without effecting the fluid separation. Finally as a liquid pump is used to provide additional compression, the energy requirements may be reduced as much as by 75% when compared to systems that require compressors. [0065] The permeation process causes the temperature of the permeate and non-permeate streams to drop. However, as stated previously, the pressure of the non-permeate stream remains above its critical pressure. Therefore, the density and viscosity of the non-permeate stream remain similar to that of the feed stream. Through optimization of the feed pressure, non-permeate staging, and interstage heating, the temperature difference between the feed stream, the permeate stream, and the non-permeate steam may remain within 30° C., preferably within 20° C., and more preferably within 10° C. [0066] The disclosure contemplates a process for the separation of a mixture containing close-boiling hydrocarbon compounds. The feed stream is at an initial temperature, preferably so that the feed stream is in liquid form. The pressure of the stream is increased to a pressure above the critical pressure of the mixture. The liquid stream is then vaporized and heated to a temperature above the critical temperature of the mixture. The resultant supercritical stream enters the membrane separator. The olefin preferentially permeates through the membrane and the remaining stream (primarily paraffin) is removed as a non-permeate stream. The olefin-enriched permeate may be cooled to form a liquid product. The non-permeate stream may then be reheated to its supercritical phase and passed through another membrane separator wherein the second non-permeate stream is collected as a paraffin product and the second permeate olefin-rich stream is recycled back to the feed stream to increase recovery of the olefin in the olefin product. The second permeate stream requires no further recompression, but simply cooling to be condensed to a liquid and readily mix with the feed stream of the process. [0067] Accordingly, the disclosed process generally comprises the steps of feeding a feed stream comprising a mixture of close-boiling hydrocarbon compounds to a first membrane at a temperature and pressure above the critical point for the mixture, said membrane having a selectivity for olefin as compared to the paraffin of at least 5.0; extracting a permeate olefin enriched stream; cooling the permeate stream; and, recovering the permeate stream as a liquid olefin product stream. [0068] Now referring to FIG. 2 , an illustration of a system for the separation of a mixture of close boiling hydrocarbon components is disclosed. System 200 comprises various elements, such as, but not limited to, pump 205 , evaporator 215 , and membrane stage 225 . These elements are interconnected by any means for connection common in the art, such as, but not limited to line(s), piping, valves, and/or the like. For example, in FIG. 2 , a line introduces feed fluid 201 to pump 205 , a line conveys the pressurized feed fluid 210 to evaporator 215 , a line conveys the supercritical feed 220 to membrane stage 225 . From membrane stage 225 , a line conveys an olefin enriched stream 230 and/or a line conveys a paraffin enriched stream 240 . [0069] In a preferred embodiment, during operation of system 200 , a feed stock or feed stream 201 comprising at least propylene and propane is introduced or injected into system 200 . In this embodiment, the feed stream may be refinery grade propylene (RGP) comprising between about 60% and about 80% propylene, preferably at least about 70% propylene. However, RGP comprising other concentrations of propylene is possible and acceptable. In general, any feed stock comprising any concentration propane and propylene can be utilized in the teachings herein. One of ordinary skill in the art will recognize that this system may also be used to separate different mixtures of close boiling hydrocarbon components. [0070] As disclosed, feed stream 201 is pumped to pressure in pump 205 . To separate a mixture comprising at least propylene and propane, the pressure of feed stream 201 is pumped to a pressure of 700 psia or higher prior to introduction to membrane stage 225 . Preferably, the pressure of feed stream 201 is pumped to a pressure of about 900 psia to about 1,100 psia prior to introduction to membrane stage 225 . In this embodiment, the pressurized feed stream 210 is then vaporized at vaporizer 215 to 96° C. or higher. As a result, the feed stream 220 is fed in its supercritical state to membrane stage 225 . One of ordinary skill in the art will recognize that different target temperatures and pressures may be necessary to adapt the system 200 to separate different mixtures of close boiling hydrocarbon components. [0071] Membrane stage 225 may utilize one or more gas separation modules (not shown). In a preferred embodiment, membrane stage 225 is selective for propylene over propane. In this embodiment, any membrane capable of effecting a propylene/propane separation can be used. Membranes capable of operating in a supercritical hydrocarbon environment and effecting a propylene/propane separation are preferred. An example of a membrane capable of operating in a hydrocarbon supercritical environment is a polyimide membrane, and particularly a polyimide membrane made of polymers sold under the tradenames P84 or P84HT from HP Polymers GmbH. Preferred membranes of P84 or P84HT are disclosed in U.S. Pat. No. 7,018,445, titled POLYIMIDE BLENDS FOR GAS SEPARATION MEMBRANES, and U.S. Pat. No. 7,422,623 titled SEPARATION MEMBRANE BY CONTROLLED ANNEALING OF POLYIMIDE POLYMERS. The entire disclosures of these applications are incorporated herein by this reference. [0072] Additional exemplary, non-limiting embodiments and/or disclosures of propane/propylene separation membranes that may be used with the systems and methods disclosed herein are detailed in U.S. Pat. No. 4,374,657; U.S. Pat. No. 4,444,571; U.S. Pat. No. 4,857,078; U.S. Pat. No. 4,952,751; U.S. Pat. Nos. 4,978,430; 5,057,641; U.S. Pat. No. 5,273,572; U.S. Pat. No. 5,326,385; U.S. Pat. No. 5,679,133; U.S. Pat. No. 6,187,196; U.S. Pat. No. 6,187,987; U.S. Pat. No. 6,517,611; U.S. Pat. No. 6,986,802; U.S. Pat. No. 6,693,018; U.S. Pat. No. 7,025,804; and, U.S. Pat. No. 7,070,694, the contents of which are hereby incorporated by reference, as if they were presented herein in their entirety. In general, any membrane apparatus for use in the separation of propylene and propane is capable of use with the present disclosure with varying degrees of performance, as would be readily apparent to one of ordinary skill in the art. [0073] In a preferred embodiment, the selectivity of the propylene/propane membrane for propylene may range from at least about 3.0 to about 20.0. Preferably, the selectivity for propylene ranges from about 5.0 to about 15.0. More preferably, the selectivity for propylene ranges from about 6.5 to about 13.0. Even more preferably, the selectivity for propylene ranges from about 8.0 to about 12.0. [0074] Due to the cooling effect in membrane stage 225 , non-permeate stream 230 and permeate stream 240 may be expected to be cooler than feed stream 220 . However, it is expected that the temperature and pressure of permeate stream 240 will be such that it remains in its gaseous state. Either or both of stream 230 and/or stream 240 may be further processed as is desired. [0075] The permeate stream 240 may pass from membrane stage 225 and be collected as a gaseous product or cooled to produce a liquid product. In the preferred embodiment, the permeate stream may be used as a chemical-grade propylene product. In this embodiment, the system 200 may be adapted to yield a permeate stream 240 having at least about 93% propylene purity. The percentage recovery of propylene may range from about 50% to about 99%, preferably from about 75% to about 99%, and more preferably from about 85% to about 99%. In the preferred embodiment, the system 200 may be adapted to yield a non-permeate stream 230 having at most about 5% propylene. The percentage recovery of propane from non-permeate stream 230 may range from about 75% to about 99%, preferably from about 80% to about 92%. However, one of ordinary skill in the art will recognize that the percent purity and recovery may vary by design and by composition of the feed stream 201 . [0076] Now referring to FIG. 3 , an illustration of an alternate embodiment of a system 300 for the separation of a mixture of close boiling hydrocarbon components is disclosed. System 300 comprises various elements, such as, but not limited to, pump 305 , first and second evaporators 315 , 335 , first and optional second condensers 365 , 385 (optional), first membrane stage 325 , and second membrane stage 345 . [0077] These elements are interconnected by any means for connection common in the art, such as, but not limited to line(s), piping, valves, and/or the like. For example, in FIG. 3 , a line introduces feed fluid 301 to pump 305 , a line conveys the pressurized feed fluid 310 to first evaporator 315 , a line conveys the supercritical feed 320 to first membrane stage 325 , etc. In a preferred embodiment, during operation of system 300 , a feed stock or feed stream 301 comprising at least propylene and propane is introduced or injected into system 300 . In this embodiment, the feed stream may be refinery grade propylene (RGP) comprising between about 60% and about 80% propylene, preferably at least about 70% propylene. However, RGP comprising other concentrations of propylene is possible and acceptable. In general, any feed stock comprising any concentration propane and propylene can be utilized in the teachings herein. One of ordinary skill in the art will recognize that this system may also be used to separate different mixtures of close boiling hydrocarbon components. [0078] Feed stream 301 is pumped to pressure in pump 305 . The pressure of feed stream 301 is pumped to a pressure above its critical pressure so that, after vaporization, the pressure of the supercritical feed stream 320 remains within its supercritical state. To separate a mixture comprising at least propylene and propane, the feed stream 301 is pumped to a pressure of 700 psia or higher, and more preferably to between about 900 psia and about 1,100 psia. The pressurized feed stream 310 is then vaporized at first evaporator 315 to a temperature of 96° C. or higher, preferably from about 100° C. to about 105° C. As a result, the feed stream 320 is fed in its supercritical state to first membrane stage 325 . One of ordinary skill in the art will recognize that different target temperatures and pressures may be necessary to adapt the system 300 to separate different mixtures of close boiling hydrocarbon components. [0079] First membrane stage 325 may utilize one or more gas separation modules (not shown). In a preferred embodiment, the first membrane stage 325 may use membranes similar to those listed above with reference to the membrane stage 225 of FIG. 2 having selectivity for propylene over propane as described above. From first membrane stage 325 , a line conveys non-permeate stream 330 and a line conveys permeate stream 340 . Permeate stream 340 will exit the first membrane stage 325 at a lower temperature than that at which stream 320 entered first membrane stage 325 . However, in a preferred embodiment, it is expected that the temperature and pressure of permeate stream 340 will be such that it remains in its gaseous state. Permeate stream 340 is conveyed to optional second condenser 385 for cooling and conveyed as a hydrocarbon stream 390 . In a preferred embodiment, hydrocarbon stream 390 contains substantial quantities of propylene, preferably greater than about 90% propylene, more preferably greater than about 92% propylene, and even more preferably greater than about 93% propylene. Stream 390 may be collected as a product, sent for further processing, used elsewhere in the process, and/or the like. [0080] Non-permeate stream 330 is typically depleted in the olefin component as compared to permeate stream 340 or feed stream 320 . However, non-permeate stream 330 is capable of containing some olefin component. Although the percentage of olefin and paraffin has changed in non-permeate stream 330 , in a preferred embodiment, the critical temperature and critical pressure for the non-permeate stream 330 remain close to that of feed stream 320 . The critical temperature and critical pressure for propylene/propane mixtures only range approximately 4° C. and approximately 60 psig, respectively. As is well known, the pressure of non-permeate stream 330 remains close to that of feed stream 320 . Therefore, when the pressure of stream 320 is sufficiently above its critical pressure, additional compression is not required to raise the pressure of non-permeate stream 330 above its supercritical pressure before sending to second membrane 345 . [0081] Due to the cooling effect in first membrane stage 325 , non-permeate stream 330 may be expected to be cooler than stream 320 . In FIG. 3 , non-permeate stream 330 is conveyed to a second evaporator 335 to heat stream 330 above its supercritical temperature prior to being fed to second membrane stage 345 . In a preferred embodiment, second evaporator 335 heats stream 330 to 96° C. or higher, preferably from about 100° C. to about 105° C. As a result, the non-permeate stream 330 is fed in it supercritical state to second membrane stage 345 . [0082] Like the first membrane stage 325 , second membrane stage 345 may utilize one or more gas separation modules (not shown). Furthermore, to minimize the temperature change between the non-permeate stream 330 , the second non-permeate stream 350 , and the second permeate stream 360 , one or more combinations of second evaporator 335 and second stage membrane 345 may be utilized in series. For example, a third evaporator (not shown) and a third membrane stage (not shown) may be placed in series with second membrane stage 345 such that they are fed by second non-permeate stream 350 with the resulting permeate stream being mixed with second permeate stream 360 and the resulting non-permeate stream being collected as product. If necessary, to further minimize temperature change, additional evaporator and membrane stage combinations may be utilized in series to process the non-permeate stream. [0083] Second membrane stage 345 is selective for the olefin component over the paraffin component, such that a paraffin-enriched stream 350 is extracted and an olefin-enriched stream 360 is extracted. In a preferred embodiment, second membrane stage 345 may use membranes similar to those listed above for the membrane stage 225 of FIG. 2 having selectivity for propylene over propane as described above. One of ordinary skill in the art will recognize that first and second membrane stages 325 and 345 may utilize the same or different membranes, which may have the same or different selectivities, depending ultimately on the intended purpose of the system 300 . [0084] The second permeate stream 360 may pass from second membrane stage 345 and into first condenser 365 for cooling, forming a liquid olefin-enriched stream 370 to be added to stream 301 to form a combined, well-mixed stream 380 . One of ordinary skill in the art will recognize how to effectively mix streams 301 and 370 . The combination of stream 370 with stream 301 may further improve recovery of olefin in stream 340 . As a result, the olefin content of stream 380 may be higher, and the paraffin content lower, than that of stream 301 . In a preferred embodiment, the system 300 may be adapted to yield a second permeate stream 360 having less than about 93% propylene purity. The percentage recovery of propylene may range from about 50% to about 99%, preferably from about 75% to about 99%, and more preferably from about 85% to about 99%. However, one of ordinary skill in the art will recognize that the percent purity and recovery may vary by design and by composition of the feed stream 301 . [0085] In a preferred embodiment, the system 300 may be adapted to yield a second non-permeate stream 350 having at most about 5% propylene. If the propylene composition of second non-permeate stream 350 is less than 5%, it may be collected as a liquefied petroleum gas (LPG) product. Alternatively, as discussed above, it may be sent to another membrane stage (not shown), set up with components similar to evaporator 335 and second membrane stage 345 . The percentage recovery of propane from second non-permeate stream 350 may range from about 50% to about 99%, preferably from about 75% to about 99%, and more preferably from about 80% to about 95%. However, one of ordinary skill in the art will recognize that the percent purity and recovery may vary by design and by composition of the feed stream 301 . [0086] Now referring to FIG. 4 , an illustration of an alternate embodiment of a system 400 for the separation of a mixture of close boiling hydrocarbon components is disclosed. System 400 discloses a feed stream 401 , pump 405 , first heat exchanger 505 , second heat exchanger 510 , third heat exchanger 515 , first evaporator 415 , first membrane stage 425 , fourth heat exchanger 520 , second evaporator 435 , second membrane stage 445 , first condenser 465 , second condenser 485 , and third condenser 525 . In order to maximize heat recovery and minimize operating costs for the system 400 , heat exchangers 505 , 510 , 515 , and 520 have been added. One of ordinary skill in the art will recognize that more or fewer heat exchangers may be used without departing from the teachings herein. [0087] These elements are interconnected by any means for connection common in the art, such as, but not limited to line(s), piping, valves, and/or the like. For example, in FIG. 4 , a line introduces feed fluid 401 to pump 405 ; lines convey the pressurized feed fluid 410 through first heat exchanger 505 , second heat exchanger 510 , third heat exchanger 515 , and first evaporator 415 ; a line conveys the supercritical feed 420 to first membrane stage 425 , etc. As in the previous figures, in a preferred embodiment, during operation of system 400 , a feed stock or feed stream 401 comprising at least propylene and propane is introduced or injected into system 400 . In this embodiment, the feed stream may be refinery grade propylene (RGP) comprising between about 60% and about 80% propylene, preferably at least about 70% propylene. However, RGP comprising other concentrations of propylene is possible and acceptable. In general, any feed stock comprising any concentration propane and propylene can be utilized in the teachings herein. One of ordinary skill in the art will recognize that this system may also be used to separate different mixtures of close boiling hydrocarbon components. [0088] Stream 401 is typically introduced to system 400 as a liquid and pumped to a pressure sufficiently above the critical pressure of stream 401 in pump 405 , producing some heat, so that the supercritical feed stream 420 remains within its supercritical range when fed to first membrane stage 425 . In a preferred embodiment, the pressure of feed stream 401 is pumped to a pressure so that the pressure of supercritical feed stream 420 is at a pressure of 700 psia or higher prior to introduction to first membrane stage 425 . Preferably, the pressure of supercritical feed stream 420 is at a pressure between about 900 psia and about 1,100 psia prior to introduction to first membrane stage 425 . One of ordinary skill in the art will recognize that different target pressures may be necessary to adapt the system 400 to separate different mixtures of close boiling hydrocarbon components. [0089] Pressurized feed stream 410 is passed through various heat exchangers for heating by and to provide cooling to other streams. For example, stream 410 may be heated by and provide cooling to streams 450 , 440 , and/or 460 . However, any one or combination of streams 450 , 440 , and/or 460 may also serve to be cooled by and to heat stream 410 . [0090] In a preferred embodiment, first evaporator 415 heats pressurized feed stream 410 to a temperature of 96° C. or higher, preferably from about 100° C. to about 105° C., resulting in supercritical stream 420 . One of ordinary skill in the art will recognize that different target temperatures may be necessary to adapt the system 400 to separate different mixtures of close boiling hydrocarbon components. Stream 420 is conveyed to first membrane stage 425 . As discussed with respect to FIGS. 2 and 3 , first membrane stage 425 may utilize one or more gas separation membrane modules (not shown). In a preferred embodiment, first membrane stage 425 may use membranes similar to those listed above for the membrane stage 225 of FIG. 2 having selectivity for propylene over propane as described above. [0091] Permeate stream 440 will exit the first membrane stage 425 at a lower temperature than that at which stream 420 entered first membrane stage 425 . However, it is expected that the temperature and pressure of permeate stream 440 will be such that it remains in its gaseous state. Permeate stream 440 is conveyed to fourth heat exchanger 520 , second heat exchanger 510 , and second condenser 485 for cooling and conveyed as a liquid hydrocarbon stream 490 . In a preferred embodiment, liquid hydrocarbon stream 490 contains substantial quantities of propylene, preferably greater than about 90% propylene, more preferably greater than about 92% propylene, and even more preferably greater than about 93% propylene. Stream 490 may be collected as a product, sent for further processing, used elsewhere in the process, and/or the like. [0092] Non-permeate stream 430 is typically depleted in olefin as compared to permeate stream 440 . However, non-permeate stream 430 is capable of containing olefin. As stated with reference to FIG. 3 , although the percentage of paraffin and olefin have changed in non-permeate stream 430 , in a preferred embodiment, the critical temperature and critical pressure for the non-permeate stream 430 remain close to that of feed stream 420 . Therefore, when the pressure of stream 420 is sufficiently above its critical pressure, additional compression is not required to raise the pressure of non-permeate stream 430 above its supercritical pressure before sending to second membrane stage 445 . [0093] Due to the cooling effect in first membrane stage 425 , however, non-permeate stream 430 may be expected to be cooler than stream 420 . The non-permeate stream 430 is passed across fourth heat exchanger 520 with permeate stream 440 . Fourth heat exchanger 520 acts to heat stream 430 and cool stream 440 . However, little heating of stream 430 may occur due to the volume of the non-permeate stream 430 being greater than that of the permeate stream 440 . Alternatively, heating of the non-permeate stream 430 in fourth heat exchanger 520 may range from none at all to more than a minimal amount. If necessary, additional heat may be provided to non-permeate stream 430 by second evaporator 435 to raise the temperature of stream 430 above its supercritical temperature. [0094] Non-permeate stream 430 is conveyed to second membrane stage 445 to produce paraffin-enriched, second non-permeate stream 450 and olefin-enriched, second permeate stream 460 . Like first membrane stage 425 , second membrane stage 445 may utilize one or more gas separation membrane modules (not shown). Furthermore, to minimize the temperature change between the non-permeate stream 430 , the second non-permeate stream 450 , and the second permeate stream 460 , one or more combinations of second evaporator 435 and second stage membrane 445 may be utilized in series. For example, a third evaporator (not shown) and a third membrane stage (not shown) may be placed in series with second membrane stage 445 such that they are fed by non-permeate stream 450 with the resulting permeate stream being mixed with second permeate stream 460 and the resulting non-permeate stream being collected as product. If necessary, to further minimize temperature change, additional evaporator and membrane stage combinations may be utilized in series to process the non-permeate stream. [0095] Second membrane stage 445 is selective for olefin over paraffin, such that a paraffin-enriched stream 450 is extracted and an olefin-enriched stream 460 is extracted. In a preferred embodiment, second membrane stage 445 may use membranes similar to those listed above for the membrane stage 225 of FIG. 2 having selectivity for propylene over propane as described above. One of ordinary skill in the art will recognize that first and second membrane stages 425 and 445 may utilize the same or different membranes, which may have the same or different selectivities, depending ultimately on the intended purpose of the system 400 . [0096] Second non-permeate stream 450 may be at or near supercritical temperature and therefore act to heat stream 410 in first heat exchanger 505 . Second non-permeate stream 450 may also be cooled in third condenser 525 and collected as a paraffin-enriched liquid product 530 . In a preferred embodiment, the system 400 may be adapted to yield a second non-permeate stream 450 having at most about 5% propylene. If the propylene composition of second non-permeate stream 450 is less than 5%, a LPG product may be collected as stream 530 after cooling in first heat exchanger 505 and third condenser 525 . Alternatively, second non-permeate steam 450 may be sent to another membrane stage (not shown), set up in the same manner with components similar to fourth heat exchanger 520 , second evaporator 435 , and second membrane stage 445 . The percentage recovery of propane from second non-permeate stream 450 may range from about 75% to about 99%, preferably from about 80% to about 92%. However, one of ordinary skill in the art will recognize that the percent purity and recovery may vary by design and by composition of the feed stream 401 . [0097] Second permeate stream 460 will be pressure depleted and olefin-enriched. At least a portion of stream 460 may act to be cooled by and to provide heat to stream 410 in third heat exchanger 515 and may be cooled in first condenser 465 . The resulting liquid olefin-enriched stream 470 may be mixed with feed stream 401 to provide for the additional recovery of olefin. As a result, the olefin content of stream 480 may be higher, and the paraffin content may be lower, than that of stream 401 . The combined liquid olefin-enriched stream 470 and feed stream 401 form well-mixed stream 480 . One of ordinary skill in the art will recognize how to effectively mix streams 401 and 470 . In a preferred embodiment, the system 400 may be adapted to yield a second permeate stream 460 having less than about 93% propylene purity. The percentage recovery of propylene may range from about 50% to about 99%, preferably from about 75% to about 99%, and more preferably from about 85% to about 99%. However, one of ordinary skill in the art will recognize that the percent purity and recovery may vary by design and by composition of the feed stream 401 . [0098] Further embodiments may comprise additional membranes as desired. For example, a further membrane may be added to separate olefin from streams 390 and 490 , such as to produce, in a preferred embodiment, a Polymer Grade Propylene Product (PGP) product. Alternatively, streams 390 and 490 may be fed to a distillation column for further processing. Further, a different arrangement of heat exchangers, evaporators, compressors, and condensers can be used within the general inventive guidelines of the present invention. The addition of another membrane allows improving olefin purity without the necessity of improving or modifying membrane structure, i.e., membrane selectivity and/or the like. In a preferred embodiment, adding at least one additional membrane increases the purity of propylene to at 99%. EXAMPLES [0099] Higher pressure reduces the module count and the higher pressure-ratio (feed pressure to the membrane divided by permeate pressure from the membrane) improves separation performance. Further maintaining the feed in a supercritical state allows operation of the permeate stream at a high enough pressure to achieve its phase change by a simple temperature change. [0100] It has been found that traditional gas separation systems require 12% more overall horsepower and 9.5% more energy for processing RGP than embodiments of the current inventive process. The current inventive process uses ⅓ more pump horsepower than the traditional gas separation approach. [0101] Application of these concepts is illustrated in the following examples. For each of these examples, membrane stages having propylene permeance of 2 and a selectivity of propylene to propane of 8 is assumed. Example [0102] Three simulations were performed based upon the system illustrated in FIG. 3 , without the optional 385 heat exchanger. In the range of operation, the fugacity coefficient of the feed and non-permeate streams below is estimated to be on the order of approximately 0.5. For an ideal gas, fugacity equals pressure and the fugacity coefficient equals 1. Due to the low fugacity coefficient of the feed stream, the actual driving force across the membrane is roughly half of the pressure-based driving force calculated below. To compensate for this, the bundle counts calculated below should be multiplied by approximately 2 to provide the estimated bundle counts actually needed to practice the disclosed system and method. [0103] The system incorporates membranes 325 and 345 having a propylene permeance of 2 and a propylene to propane selectivity of 8. One of ordinary skill in the art will recognize that membranes 325 and 345 having different selectivities may also be utilized, depending ultimately on the intended purpose of the apparatus. For example, one of ordinary skill in the art will recognize that an increase in the membrane selectivity will result in the need for more membrane modules and that a decrease in the membrane selectivity will result in the need for a larger pump 305 . [0104] In each of the three simulations, a feed 301 containing 70.0% (v/v) propylene, 29.8% (v/v) propane, and 0.2% (v/v) iso-butane at a flow of 5326 Nm 3 /hr, 198.7 psig, and 15.0° C. is fed to pump 305 . Pump 305 pressurizes the stream to 1099.0, 899.0, or 699.0 psig respectively. Evaporator 315 vaporizes the pressurized stream 310 to a temperature of 105.0, 100.0, or 100.0° C., respectively. First membrane stage 325 is used to separate the feed into a propylene enriched stream 340 containing approximately 93% propylene and a propane enriched stream 330 . The propane enriched stream 330 is reheated by evaporator 335 to 105.0, 100.0, or 100.0° C., respectively, and further processed by second membrane stage 345 into a 95% propane product 350 and a lower pressure propylene-enriched stream 360 . Stream 360 is cooled by condenser 365 . The resulting propylene-enriched stream 370 is commingled with the feed 301 to produce stream 380 . The combined stream 380 is fed to the pump 305 . As stated previously, as a result of the addition of liquid propylene-enriched stream 370 , the propylene content of the stream 380 fed to the pump 305 may be higher than or equal to, and the propane content lower than or equal to, that of feed stream 301 . [0105] Table 2 lists the various properties of the 1099.0 psig pressurization simulation. Table 3 lists the various properties of the 899.0 psig pressurization simulation. Table 4 lists the various properties of the 699.0 psig pressurization simulation. [0000] TABLE 2 Stream Properties for 1099.0 psig pressurization Feed Residue Permeate Feed Residue Permeate Total Bundle Count 182 Stream # 301 320 330 340 330 350 360 Flow [Nm3/hr] 5326 14954 11051 3903 11051 1391 9660 Pressure [psig] 198.7 1099.0 1099.0 200.0 1096 1092 200 Temp [C.] 15.0 105.0 85.8 97.9 105 67 82 % Propylene 70.0 72.3 65.0 93.0 65.0 4.4 73.7 % Propane 29.8 27.5 34.8 6.9 34.8 95.2 26.1 % iso-Butane 0.2 0.2 0.2 0.1 0.2 0.4 0.2 Density [g/cm 3 ] 0.518 0.350 0.408 0.023 0.408 0.447 0.025 Viscosity [cp] 0.105 0.045 0.059 0.011 0.059 0.074 0.011 Flow [lb/hr] 22374 62754 46542 16212 46542 6028 40515 Total Pump + Recycle Energy [KW] 131 Total Heating Energy [KW] 3104 Total Cooling Energy [KW] 3016 [0000] TABLE 3 Stream Properties for 899.0 psig pressurization Feed Residue Permeate Feed Residue Permeate Total Bundle Count 291 Stream # 301 320 330 340 330 350 360 Flow [Nm3/hr] 5326 17926 14035 3891 14035 1397 12638 Pressure [psig] 198.7 899.0 898.5 200.0 896 891 200 Temp [C.] 15.0 100.0 87.0 97.2 100 68 75 % Propylene 70.0 72.9 67.3 93.0 67.3 4.6 76.3 % Propane 29.8 26.9 32.5 6.9 32.5 95.0 23.5 % iso-Butane 0.2 0.2 0.2 0.1 0.2 0.4 0.2 Density [g/cm 3 ] 0.518 0.337 0.390 0.023 0.390 0.437 0.025 Viscosity [cp] 0.105 0.043 0.054 0.011 0.054 0.070 0.010 Flow [lb/hr] 22374 75208 59045 16163 59045 6053 52992 Total Pump + Recycle Energy [KW] 123 Total Heating Energy [KW] 3655 Total Cooling Energy [KW] 3573 [0000] TABLE 4 Stream Properties for 699.0 psig pressurization Feed Residue Permeate Feed Residue Permeate Total Bundle Count 657 Stream # 301 320 330 340 330 350 360 Flow [Nm3/hr] 5326 27393 23510 3884 23510 1413 22097 Pressure [psig] 198.7 699.0 697.9 200.0 695 691 200 Temp [C.] 15.0 100.0 98.4 99.9 100 52 95 % Propylene 70.0 74.1 70.9 93.1 70.9 4.5 80.5 % Propane 29.8 25.7 28.9 6.8 28.9 95.1 19.3 % iso-Butane 0.2 0.2 0.2 0.1 0.2 0.4 0.2 Density [g/cm 3 ] 0.518 0.167 0.199 0.023 0.199 0.461 0.023 Viscosity [cp] 0.105 0.020 0.023 0.011 0.023 0.080 0.011 Flow [lb/hr] 22374 114860 98729 16131 98729 6123 92606 Total Pump + Recycle Energy [KW] 135 Total Heating Energy [KW] 6084 Total Cooling Energy [KW] 6029 [0106] As discussed previously, although the non-permeate stream exhibits a temperature below its critical temperature, thereby forming a liquid, the density and viscosity of the non-permeate stream remain close to that of the supercritical feed stream, providing less concern about phase change. The system and method disclosed operate most efficiently when the ratios of the viscosity and the density of the non-permeate stream to that of the feed stream approach 1. [0107] At the first membrane stage of the 1099.0 psig pressurization system, the viscosity ratio between the residue and feed stream is 1.3 and the density ratio between the same is 1.16. The viscosity ratio between the residue and feed stream at the first membrane stage of the 899.0 psig pressurization system is 1.2 and its density ratio for the same is 1.16. Similarly, the viscosity ratio between the residue and feed stream at the first membrane stage of the 699.0 psig pressurization system is 1.2 and its density ratio for the same is 1.19. [0108] At the second membrane stage of the 1099.0 psig pressurization system, the viscosity ratio between the residue and feed stream is 1.2 and the density ratio between the same is 1.10. The viscosity ratio between the residue and feed stream at the first membrane stage of the 899.0 psig pressurization system is 1.3 and its density ratio for the same is 1.12. In contrast, the viscosity ratio between the residue and feed stream at the first membrane stage of the 699.0 psig pressurization system is 3.5 and its density ratio for the same is 2.32. [0109] As can be seen, the 1099.0 psig pressurization provides the best results. The 1099.0 psig pressurization apparatus utilizes less membrane modules than the 899.0 and 699.0 examples (see total bundle count). It also utilizes less heating and cooling energy. Finally, the 1099.0 psig pressurization exhibits a smaller viscosity and density ratio between the residue and feed streams of the second membrane stage, which is beneficial to operation of the disclosed membranes and process. [0110] It will be understood that many additional changes in the details, materials, steps, and arrangement of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. Thus, the present invention is not intended to be limited to the specific embodiments in the examples given above and/or the attached drawings.

Disclosed are membrane-based systems and methods for the separation of mixtures containing close-boiling hydrocarbon components that overcome certain issues associated with prior art devices.

FIELD OF THE INVENTION [0001] The invention relates to vancomycin derivatives and preparation processes thereof. BACKGROUND OF THE INVENTION [0002] After penicillin was used clinically in 1940, thousands of antibiotics have been developed, and also hundreds are commonly used in clinical practice. In 2006, among the 500 best-selling drugs in the world, there were 77 anti-infective drugs, which were the first of 19 categories of drugs. Due to wide use of antibiotics in clinical practice, drug resistance has been gradually evolved in bacteria, causing that more and more antibiotics lose their effectiveness gradually. [0003] Vancomycin is a glycopeptide antibiotic produced by the Streptomyces orientalis strain. It was approved by US FDA for clinical use in 1958, effective mainly against Gram-positive bacteria with strong antibacterial activity, and was ever deemed as the last line of defense for human being against bacterial infections. Until 1990s, i.e. after vancomycin had been used for nearly 40 years, bacteria resistant to vancomycin were found and caused panic in the medical field. Therefore, there is an urgent need for discovery and modification of antibiotics. [0004] During modification of vancomycin in a lone time period, scientists from Eli Lilly found in WO9630401A1 that introduction of an aliphatic or aromatic chain into the polysaccharide moiety of such compounds can improve their activities greatly and even show a very good inhibitory effect against drug-resistant bacteria, e.g. Oritavancin as shown by the following formula: [0000] [0005] “Synthesis of Vancomycin from the Aglycon.” J. Am. Chem. Soc. 1999, 121, 1237-1244 demonstrated that vancomycin derivatives modified by a long chain show dual mechanisms of action in the bacteria-killing process: in addition to the original binding mechanism of the polypeptide moiety, the polysaccharide moiety is able to inhibit the glycosyl transferase involved in the process of synthesizing cell wall. These two mechanisms are complementary each other so as to reach the objective of enhancing the activity significantly. [0006] However, with introduction of the aliphatic and aromatic chains, the liposolubility (Log P) of such novel compounds increases greatly, and thus binding to ion channels as well as toxic and side effects on the cardiovascular system also increase, which may be adverse to the cardiovascular system. SUMMARY OF THE INVENTION [0007] The present invention provides vancomycin derivatives and preparation processes thereof, which derivatives have effectively increased water-solubility and reduced liposolubility, thereby solving the problem resulted from high liposolubility. [0008] Specifically, provided is compounds having the following formula: [0000] [0009] wherein: [0010] R 1 is —NHCH 3 or —NH 2 ; [0011] R 2 is H or 4-epi-vancosaminyl; [0012] R 3 is —(R)COOR a or —(S)COOR a or —(R/S)COOR a , and R a is H, C1-C20 alkyl, C5-C12 aryl, C2-C12 alkenyl or C2-C12 alkynyl; [0013] R 4 is hydrogen, C1-C20 alkyl, C5-C12 aryl, C2-C12 alkenyl, C2-C12 alkynyl, (C1-C20 alkyl)-R 5 or (C1-C20 alkyl)-O—R 5 , and R 5 has the structure as listed below: [0014] (a) unsubstituted C5-C 12 aryl or mono-substituted C5-C12 aryl or poly-substituted C5-C12 aryl, wherein the substituent independently is: [0015] (I) hydroxyl [0016] (II) halogen [0017] (III) nitro [0018] (IV) amino [0019] (V) C1-C20 alkyl [0020] (b) the following structure: [0000] [0021] A 1 is —OC(A 2 )2—C(A 2 )2-O— or —O—C(A 2 )2-O— or —C(A 2 )2-O— or —C(A 2 )2-N— or —C(A 2 )2—C(A 2 )2—C(A 2 )2—C(A 2 )2-, wherein A 2 independently is hydrogen or C1-C20 alkyl [0022] (c) the following structure: [0000] [0023] p is 1-5, wherein R 7 independently is the following group: [0024] (I) hydrogen [0025] (II) hydroxyl [0026] (III) halogen [0027] (IV) nitro [0028] (V) amino [0029] (VI) C1-C20 alkyl [0030] (d) the following structure: [0000] [0031] q is 0-4, wherein R 7 independently is the following group: [0032] (I) hydrogen [0033] (II) hydroxyl [0034] (III) halogen [0035] (IV) nitro [0036] (V) amino [0037] (VI) C1-C20 alkyl [0038] r is 1-5, but q+r is no more than 5 [0039] Z is the following case: [0040] (I) a single bond [0041] (II) —(C1-C12)alkyl- [0042] R 8 independently is: [0043] (I) C5-C12 aryl [0044] (II) C5-C12 heteroaryl [0045] (III) phenyl unsubstituted or substituted with 1 to 5 substituents independently selected from: [0046] (a) hydrogen [0047] (b) hydroxyl [0048] (c) halogen [0049] (d) nitro [0050] (e) amino [0051] (f) C1-C20 alkyl. [0052] Provided is a vancomycin derivative as shown in formula (I): [0000] [0053] wherein: [0054] R 1 is —NHCH 3 or —NH 2 ; [0055] R 2 is H or 4-epi-vancosaminyl; [0056] R 3 is —(R)COOR a or —(S)COOR a or —(R/S)COOR a ; wherein R a is H, C1-C20 alkyl, C5-C12 aryl, C2-C12 alkenyl or C2-C12 alkynyl; [0057] R 4 is C1-C20 alkyl. [0058] Provided is a vancomycin derivative as shown in formula (I): [0000] [0059] wherein: [0060] R 1 is —NHCH 3 or —NH 2 ; [0061] R 2 is H or 4-epi-vancosaminyl; [0062] R 3 is —(R)COOR a or —(S)COOR a or —(R/S)COOR a ; wherein R a is H, C1-C20 alkyl, C5-C12 aryl, C2-C12 alkenyl or C2-C12 alkynyl; [0063] R 4 is (C1-C20 alkyl)-R 5 , wherein R 5 has the following structure: [0000] [0064] p is 1-5, wherein R 7 independently is the following group: [0065] (I) hydrogen [0066] (II) hydroxyl [0067] (III) halogen [0068] (IV) nitro [0069] (V) amino [0070] (VI) C1-C20 alkyl. [0071] Provided is a vancomycin derivative as shown in formula (I): [0000] [0072] wherein: [0073] R 1 is —NHCH 3 or —NH 2 ; [0074] R 2 is H or 4-epi-vancosaminyl; [0075] R 3 is —(R)COOR a or —(S)COOR a or —(R/S)COOR a ; wherein R a is H, C1-C20 alkyl, C5-C12 aryl, C2-C12 alkenyl or C2-C12 alkynyl; [0076] R 4 is (C1-C20 alkyl)-R 5 , wherein R 5 has the following structure: [0000] [0077] q is 0-4, wherein R 7 independently is the following group: [0078] (I) hydrogen [0079] (II) hydroxyl [0080] (III) halogen [0081] (IV) nitro [0082] (V) amino [0083] (VI) C1-C20 alkyl [0084] r is 1-5, but q+r is no more than 5 [0085] Z is the following case: [0086] (I) a single bond [0087] (II) —(C1-C12)alkyl- [0088] R 8 independently is: [0089] (I) C5-C12 aryl [0090] (II) C5-C12 heteroaryl [0091] (III) phenyl unsubstituted or substituted with 1 to 5 substituents independently selected from: [0092] (a) hydrogen [0093] (b) hydroxyl [0094] (c) halogen [0095] (d) nitro [0096] (e) amino [0097] (f) C1-C20 alkyl. [0098] Provided is a vancomycin derivative as shown in formula (I): [0000] [0099] wherein: [0100] R 1 is —NHCH 3 or —NH 2 ; [0101] R 2 is H or 4-epi-vancosaminyl; [0102] R 3 is —(R)COOR a or —(S)COOR a or —(R/S)COOR a ; wherein R a is H; [0103] R 4 is (C1-C20 alkyl)-R 5 , wherein R 5 has the following structure: [0000] [0104] q is 0-4, wherein R 7 independently is the following group: [0105] (I) hydrogen [0106] (II) hydroxyl [0107] (III) halogen [0108] (IV) nitro [0109] (V) amino [0110] (VI) C1-C20 alkyl [0111] r is 1-5, but q+r is no more than 5 [0112] Z is the following case: [0113] (I) a single bond [0114] (II) —(C1-C12)alkyl- [0115] R 8 independently is: [0116] (I) C5-C12 aryl [0117] (II) C5-C12 heteroaryl [0118] (III) phenyl unsubstituted or substituted with 1 to 5 substituents independently selected from: [0119] (a) hydrogen [0120] (b) hydroxyl [0121] (c) halogen [0122] (d) nitro [0123] (e) amino [0124] (f) C1-C20 alkyl. [0125] Provided is a medicament, which comprises the compound of formula (I) or a clinically acceptable salt thereof and is useful for treatment of infection caused by gram-positive bacteria or vancomycin-resistant bacteria. [0126] Provided is a process for preparing vancomycin derivatives, in which [0127] the product is obtained from reductive reaction of vancomycin or an analogue thereof and a compound of formula [0000] [0000] with a reductive agent in a polar solvent followed by hydrolysis, and if R a is H in the formula, the product is directly obtained after reduction without further hydrolysis; [0128] the vancomycin and the analogue thereof are vancomycin of formula (II), norvancomycin of formula (III), 4-epi-vancosaminyl vancomycin of formula (IV) or 4-epi-vancosaminyl norvancomycin of formula (V): [0000] [0129] M is alkali metal or alkaline earth metal; [0130] R 3 is —(R)COOR a or —(S)COOR a or —(R/S)COOR a , and R a is H, C1-C20 alkyl, C5-C12 aryl, C2-C12 alkenyl, or C2-C12 alkynyl; [0131] R 4 is hydrogen, C1-C20 alkyl, C5-C12 aryl, C2-C12 alkenyl, C2-C12 alkynyl, (C1-C20 alkyl)-R 5 or (C1-C20 alkyl)-O—R 5 , and R 5 has the structure as listed below: [0132] (a) unsubstituted C5-C12 aryl or mono-substituted C5-C12 aryl or poly-substituted C5-C12 aryl, wherein the substituent independently is: [0133] (I) hydroxyl [0134] (II) halogen [0135] (III) nitro [0136] (IV) amino [0137] (V) C1-C20 alkyl [0138] (b) the following structure: [0000] [0139] A 1 is —OC(A 2 )2—C(A 2 )2-O— or —O—C(A 2 )2-O— or —C(A 2 )2-O— or —C(A 2 )2-N— or —C(A 2 )2—C(A 2 )2—C(A 2 )2—C(A 2 )2-, wherein A 2 independently is hydrogen or C1-C20 alkyl [0140] (c) the following structure: [0000] [0141] p is 1-5, wherein R 7 independently is the following group: [0142] (I) hydrogen [0143] (II) hydroxyl [0144] (III) halogen [0145] (IV) nitro [0146] (V) amino [0147] (VI) C1-C20 alkyl [0148] (d) the following structure: [0000] [0149] q is 0-4, wherein R 7 independently is the following group: [0150] (I) hydrogen [0151] (II) hydroxyl [0152] (III) halogen [0153] (IV) nitro [0154] (V) amino [0155] (VI) C1-C20 alkyl [0156] r is 1-5, but q+r is no more than 5 [0157] Z is the following case: [0158] (I) a single bond [0159] (II) —(C1-C12)alkyl- [0160] R 8 independently is: [0161] (I) C5-C12 aryl [0162] (II) C5-C12 heteroaryl [0163] (III) phenyl unsubstituted or substituted with 1 to 5 substituents independently selected from: [0164] (a) hydrogen [0165] (b) hydroxyl [0166] (c) halogen [0167] (d) nitro [0168] (e) amino [0169] (f) C1-C20 alkyl. [0170] The polar solvent is methanol, ethanol, iso-propanol, tert-butanol, N,N-dimethylformamide, N,N-dimethylacetamide; the temperature is between 0 and 80° C.; the reductive agent is sodium borohydride, potassium borohydride, borane or a complex containing borane, sodium cyano borohydride, potassium cyano borohydride, sodium triacetoxy borohydride, potassium triacetoxy borohydride; the equivalent ratio of vancomycin to the reductive agent is 1:0.8-5.0. [0171] The present invention is described in detail as follows: [0172] Unless otherwise stated, as used herein, halogen refers to fluorine, chlorine, bromine, iodine, represented by X. [0173] Unless otherwise stated, as used herein, C1-C20 alkyl refers to C1-C20 hydrocarbon radical which is normal, secondary, tertiary or cyclic and contains 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 carbon atoms, and the examples of which include, but are not limited to, the following structures: [0174] —CH 3 , —CH 2 CH 3 , —CH 2 CH 2 CH 3 , —CH(CH 3 ) 2 , —CH 2 CH 2 CH 2 CH 3 , —CH 2 CH(CH 3 ) 2 , —CH(CH 3 )CH 2 CH 3 , —C(CH 3 ) 3 , —CH 2 CH 2 CH 2 CH 2 CH 3 , —CH(CH 3 )CH 2 CH 2 CH 3 , —CH(CH 2 CH 3 ) 2 , —C(CH 3 ) 2 CH 2 CH 3 , —CH(CH 3 )CH(CH 3 ) 2 , —CH 2 CH 2 CH(CH 3 ) 2 , —CH 2 CH(CH 3 )CH 2 CH 3 , —CH 2 C(CH 3 ) 3 , —CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 , —CH(CH 3 )CH 2 CH 2 CH 2 CH 3 , —CH(CH 2 CH 3 )(CH 2 CH 2 CH 3 ), —C(CH 3 ) 2 CH 2 CH 2 CH 3 , —CH(CH 3 )CH(CH 3 )CH 2 CH 3 , —CH(CH 3 )CH 2 CH(CH 3 ) 2 , —C(CH 3 )(CH 2 CH 3 ) 2 , —CH(CH 2 CH 3 )CH(CH 3 ) 2 , —C(CH 3 ) 2 CH(CH 3 ) 2 , —CH(CH 3 ) 2 C(CH 3 ) 3 , cyclopropyl, cyclobutyl, cyclopropylmethyl, cyclopentyl, cyclobutylmethyl, 1-cyclopropyl-1-ethyl, 2-cyclopropyl-1-yl, cyclohexyl, cyclopentylmethyl, 1-cyclobutyl-1-ethyl, 2-cyclobutyl-1-ethyl, 1-cyclopropyl-1-propyl, 2-cyclopropyl-1-propyl, 3-cyclopropyl-1-propyl, 2-cyclopropyl-2-propyl and 1-cyclopropyl-2-propyl. [0175] Unless otherwise stated, as used herein, C2-C12 alkenyl refers to C2-C12 alkene radical which is normal, secondary, tertiary or cyclic and contains 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms, and the examples of which include, but are not limited to, —CH═CH 2 , —CH═CHCH 3 , —CH 2 CH═CH 2 , —C(═CH 2 )(CH 3 ), —CH═CHCH 2 CH 3 , —CH 2 CH═CHCH 3 , —CH 2 CH 2 CH═CH 2 , —CH═C(CH 3 ) 2 , —CH 2 C(═CH 2 )(CH 3 ), —C(═CH 2 )CH 2 CH 3 , —C(CH 3 )═CHCH 3 , —C(CH 3 )CH═CH 2 , —CH═CHCH 2 CH 2 CH 3 , —CH 2 CH═CHCH 2 CH 3 , —CH 2 CH 2 CH═CHCH 3 , —CH 2 CH 2 CH 2 CH═CH 2 , —C(═CH 2 )CH 2 CH 2 CH 3 , —C(CH 3 )═CHCH 2 CH 3 , —CH(CH 3 )CH═CHCH 3 , —CH(CH 3 )CH 2 CH═CH 2 , —CH 2 CH═C(CH 3 ) 2 , 1-cyclopent-1-enyl, 1-cyclopent-2-enyl, 1-cyclopent-3-enyl, 1-cyclohex-1-enyl, 1-cyclohex-2-enyl and 1-cyclohexyl-3-enyl. [0176] Unless otherwise stated, as used herein, C2-C12 alkynyl refers to C2-C12 alkyne radical which is normal, secondary, tertiary or cyclic and contains 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms, and the examples of which include —CCH, —CCCH 3 , —CH 2 CCH, —CCCH 2 CH 3 , —CH 2 CCCH 3 , —CH 2 CH 2 CCH, —CH(CH 3 )CCH, —CCCH 2 CH 2 CH 3 , —CH 2 CCCH 2 CH 3 , —CH 2 CH 2 CCCH 3 and —CH 2 CH 2 CH 2 CCH. [0177] Unless otherwise stated, as used herein, C5-C 12 aryl includes, but is not limited to, an aromatic ring containing 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms or an aromatic ring containing heteroatoms such as O, N, S and the like. The examples are: [0000] [0178] Salts include those formed with suitable anions such as the anions derived from inorganic or organic acids. Suitable acids include those which are sufficient acidic to form stable salts, preferably the acids with low toxicity. For example, the salts of the present invention can be formed by acid addition with certain inorganic or organic acids (such as HF, HCl, HBr, HI, H 2 SO 4 , H 3 PO 4 ) or by addition of organic sulfonic acids or organic carboxylic acids with basic centers (typically, an amine). Organic sulfonic acids include C6-C16 aryl sulfonic acid, C6-C16 heteroaryl sulfonic acid and C1-C16 alkyl sulfonic acid such as phenyl sulfonic acid, methanesulfonic acid, ethanesulfonic acid, n-propyl sulfonic acid, isopropyl sulfonic acid, n-butyl sulfonic acid, sec-isobutyl sulfonic acid, tert-butyl sulfonic acid, pentyl sulfonic acid and hexyl sulfonic acid. Examples of organic carboxylic acids include C6-C16 aryl carboxylic acid, C4-C16 heteroaryl carboxylic acid and C1-C16 alkyl carboxylic acid such as acetic acid, glycolic acid, lactic acid, pyruvic acid, malonic acid, glutaric acid, tartaric acid, citric acid, fumaric acid, succinic acid, malic acid, maleic acid, hydroxyl maleic acid, benzoic acid, hydroxyl benzoic acid, phenylacetic acid, cinnamic acid, salicylic acid and 2-phenoxy benzoic acid. Salts also include addition salts of the compounds of the present invention with one or more amino acids. Many amino acids are suitable, especially those naturally occurring as components of proteins and however, typically those containing a basic or acidic group on the side chain (e.g. lysine, arginine or glutamic acid) or those containing a neutral group (e.g. glycine, serine, threonine, alanine, isoleucine or leucine). These salts are generally biologically compatible or pharmaceutically acceptable or non-toxic, particularly for mammals. Salts of the compounds of the present invention can be in a crystalline or amorphous form. [0179] Unless otherwise stated, as used herein, [0000] [0000] includes, but is not limited to, the following groups: [0000] [0180] Unless otherwise stated, as used herein, [0000] [0000] includes, but is not limited to, the following groups: [0000] [0181] R 7 is C 1-12 alkyl or C 1-12 alkoxyl [0182] Unless otherwise stated, as used herein, [0000] [0000] includes, but is not limited to, the following groups: [0000] [0183] wherein R 8 independently is: [0184] (I) C5-C12 aryl [0185] (II) C5-C12 heteroaryl [0186] (III) phenyl unsubstituted or substituted with 1 to 5 substituents independently selected from: [0187] (a) hydrogen [0188] (b) hydroxyl [0189] (c) halogen [0190] (d) nitro [0191] (e) amino [0192] (f) C1-C20 alkyl. [0193] Beneficial Effects: [0194] (1) The present invention provides a group of compounds, wherein a glycerate moiety is introduced between the vancomycin derivative and the liposoluble modifying group, thereby providing the compounds with a property of high solubility in water similar to amino acids and thus effectively increasing water-solubility and reducing liposolubility of the compounds, so as to solve the problem resulted from high liposolubility and reduce the side effects on the cardiovascular system after being prepared into a medicament. [0195] (2) The present invention provides a group of compounds, most of which exhibit varying degrees of inhibitory activity against vancomycin-sensitive bacteria, wherein aliphatic long chain and substituted biphenyl derivatives have the inhibitory activity superior to that of vancomycin, which is positive for treatment of vancomycin-resistant bacteria infection. DETAILED DESCRIPTION OF THE INVENTION [0196] In vitro Activity Assay [0197] The compound of formula 1 of the present invention or a clinically acceptable salt thereof is intended to be used for treatment of gram-positive bacteria or vancomycin-resistant bacteria infection cases. [0198] To verify the activity, a group of the compounds of the present invention were preferably subjected to in vitro activity assay (Table 1). [0000] TABLE 1 The compounds of formula (I) No. Structure V9 V11 V51 V61 V62 V63 V20 V21 V52 V22 V23 V25 V24 V53 V54 V13 V15 V55 V64 V65 V66 V26 V27 V33 V30 V57 V31 V16 V19 V58 V32 V59 V60 V67 V68 V69 [0199] In vitro activity assay was performed according to Microbiological Identification of Antibiotics, Appendix XIA, Volume II, Chinese Pharmacopoeia 2010. Vancomycin-sensitive Staphylococcus aureus strains (Newman and Mu 50) were selected as the test strains, and trypticase soy broth was selected as the culture medium. The assay for minimum inhibitory concentration (MIC) was performed as follows: the compound to be tested was dissolved in N,N-dimethylformamide to prepare a stock solution at 1.28 mg/ml, the stock solution was diluted with the culture medium to a initial concentration of 1.28 μg/ml, which was subsequently half diluted to prepare test solutions at 64 μg/ml-0.125 μg/ml, and the assay was performed according to Cup-Plate Method, Microbiological Identification of Antibiotics, Appendix XIA, Volume II, Chinese Pharmacopoeia 2010, wherein vancomycin and blank were used as controls. The results of in vitro activity assay of the compounds of formula (I) are listed in Table 2. [0000] TABLE 2 MIC values (μg/ml) Test strains Staphylococcus Compounds Staphylococcus aureus Newman aureus Mu50 V9 8 32 V11 8 32 V13 <0.125 2 V15 <0.125 2 V16 16 64 V19 64 >128 V20 <0.125 2 V21 <0.125 2 V22 2 8 V23 2 8 V24 4 8 V25 4 8 V26 16 64 V27 16 64 V30 4 16 V31 2 8 V32 2 8 V33 16 64 V51 8 32 V52 <0.125 2 V53 <0.125 2 V54 <0.125 2 V55 <0.125 2 V57 4 16 V58 64 >128 V59 2 8 V60 2 8 V61 4 8 V62 4 8 V63 <0.125 2 V64 <0.125 2 V65 <0.125 2 V66 <0.125 2 V67 2 4 V68 4 8 V69 2 8 DMSO >128 >128 Vancomycin 2 8 [0200] It is seen from the results that each group of the compounds exhibited varying degrees of antibacterial activity against vancomycin-sensitive Staphylococcus aureus strains. With increase in liposolubility of the group R 5 , there is a trend in which the inhibitory activity of the compounds against the bacteria is enhanced. [0201] Solubility Test of Compounds [0202] Solubility test of each compound was performed according to the guidelines of General Notices, Volume II, Chinese Pharmacopoeia 2005: weigh out finely powdered compound, place the compound in different volumes of water, strongly shake for 30 seconds at an interval of 5 minutes; observe the solubility behavior within 30 minutes, and obtain the solubility range of the compound, wherein all the solubility data range are measured at a temperature of 25° C. Solubility of vancomycin and the analogues thereof are listed in Table 3. [0000] TABLE 3 Solubility of the compounds in water Solubility in water Compounds (mg/ml) Vancomycin ≧100 Oritavancin <0.1 (data from US2010/045201) V9 <0.1 V11 50-60  V13 50-60  V15 ≧60 V16 ≧60 V19 50-60  V20 <5 V21 >8 V22 <5 V23 >8 V24 >10 V25 <5 V26 4.5 V27 20 V30 4 V31 <1 V32 50-60  V33 5 V51 20 V52 20 V53 20 V54 15-20  V55 3 V57 >60 V58 50-60  V59 <10 V60 >20 V61 20 V62 5-20 V63 5-20 V64 5-20 V65 5-20 V66 5-20 V67 5-10 V68 5-10 V69 5-10 [0203] It is seen from the solubility data that after introducing a glycerate moiety into the structure, the solubility of the compound in water increases by 1-2 orders of magnitude as compared to Oritavancin. This result demonstrates that the glycerate moiety plays a critical role in increasing the solubility in water. [0204] Preparation Process [0205] Provided is a preparation process, which is a process for preparing the vancomycin derivative according to any one of claims 1 - 5 : [0000] [0206] and in which the product is obtained from reductive reaction of vancomycin or an analogue thereof and a compound of formula [0000] [0000] with a reductive agent in a polar solvent followed by hydrolysis, and if R a is H in the formula, the product is directly obtained after reduction without further hydrolysis; [0207] specifically, the reaction is performed as follows: [0000] [0208] The present invention is further illustrated by the following examples, which should not be construed as limiting the present invention. EXAMPLE 1 [0209] [0210] Synthetic Procedure: [0211] Step 1: [0000] [0212] A 500 ml single necked flask was charged with 2.19 g of sodium hydride, suspended with 100 ml of N,N-dimethylformamide, cooled to 0-5° C. under nitrogen atmosphere, 10.0 g of 4-chlorophenyl benzyl alcohol was dissolved in 100 ml of N,N-dimethylformamide and was added to the reaction solution dropwise slowly, and after addition, the reaction was stirred for 0.5 hour followed by addition of 7.6 g of ethyl bromoacetate, and after addition, the temperature was raised to 35-40° C. overnight, and after the reaction completed as shown by TLC, the reaction was poured into 1 L of ice-water and was added with 500 ml of ethyl acetate for extraction, the organic phase was washed with saturated sodium chloride, dried over anhydrous sodium sulfate and then concentrated to dryness by a rotary evaporator to obtain a crude product, which was purified by column eluted with 10% ethyl acetate/petroleum ether to obtain 11.0 g of an oily liquid with a yield of 83.0%. [0213] Step 2: [0000] [0214] A 100 ml single necked flask was charged with 2.5 g of potassium tert-butoxide, dispersed with 15 ml of diethyl ether, a solution of 5.9 g of the product obtained from the previous step in 2.2 ml of methyl formate was added slowly under nitrogen atmosphere, the reaction solution was reacted at room temperature overnight, and after the reaction completed as shown by TLC, 50 ml of diethyl ether was added and stirred for 0.5 hour followed by suction filtration, the filter cake was dried under reduced pressure to obtain 5.6 g of a white solid. [0215] Step 3: [0000] [0216] A 100 ml single necked flask was charged with 743 mg of vancomycin, which was dissolved in 40 ml of N,N-dimethylformamide at 80° C., 214 mg of the product obtained from the previous step was added, followed by addition of 63 mg of sodium cyano borohydride in batch, and after addition, the reaction was performed for 2 hours, 1 ml of acetic acid was added and stirred for 0.5 hour, the reaction solution was poured into 50 ml of diethyl ether whereupon a solid precipitated, suction filtration was performed, the filter cake was stirred/washed with 40 ml of a solvent mixture of methanol and diethyl ether (1:3) followed by suction filtration, the crude product thus obtained was isolated by preparative HPLC to obtain 100 mg of the product. MS m/e 1750.4, 1751.4, 1752.4 (M+1) [0217] Step 4: [0000] [0218] 30 mg of the product obtained from the previous step was dissolved in a solvent mixture of 3 ml of tetrahydrofurane and 3 ml of water, 4.6 mg of lithium hydroxide was added with stirring, the reaction solution was stirred for 4 hours, 18 mg of acetic acid was added to quench the reaction, the organic solvent was removed by a rotary evaporator, purification by preparative HPLC obtained 9.7 mg of the product, MS m/e 1736.5, 1738.5, 1739.5 (M+1) EXAMPLE 2 [0219] Compounds V9, V11, V13, V15, V20, V21, V22, V23, V24, V25, V55, V61 and the like were prepared according to the process as described in Example 1. EXAMPLE 3 [0220] [0221] Synthetic Procedure: [0222] Step 1: [0000] [0223] A 100 ml single necked flask was charged with 20 ml of n-butanol, 1.80 g of pieces of sodium was added in an ice-water bath, and after addition, the mixture was heated at reflux until the solid dissolved, cooled to room temperature, 10.0 g of ethyl bromoacetate was added, after which the temperature was raised to 40-50° C., stirred overnight, and after the reaction completed as shown by TLC, 100 ml of diethyl ether was added, the mixture was washed with 50 ml of water three times, the organic phase was dried by a rotary evaporator under reduced pressure to obtain 9.1 g of an oily liquid, which was directly used in the next step. [0224] Step 2: [0000] [0225] A 100 ml single necked flask was charged with 2.5 g of potassium tert-butoxide, dispersed with 15 ml of diethyl ether, a solution of 3.0 g of the product obtained from the previous step in 2.2 ml of methyl formate was added slowly under nitrogen atmosphere, the reaction solution was reacted at room temperature overnight, and after the reaction completed as shown by TLC, 50 ml of diethyl ether was added and stirred for 0.5 hour followed by suction filtration, the filter cake was dried under reduced pressure to obtain 2.9 g of a white solid. [0226] Step 3: [0000] [0227] A 250 ml single necked flask was charged with 1.48 g of vancomycin, which was dissolved in 80 ml of N,N-dimethylformamide at 80° C., 276 mg of the product obtained from the previous step was added, followed by addition of 126 mg of sodium cyano borohydride in batch, and after addition, the reaction was performed for 2 hours, 5 ml of acetic acid was added and stirred for 0.5 hour, the reaction solution was poured into 100 ml of diethyl ether whereupon a solid precipitated, suction filtration was performed, the filter cake was stirred/washed with 40 ml of a solvent mixture of methanol and diethyl ether (1:3) followed by suction filtration, the crude product thus obtained was isolated by preparative HPLC to obtain 56 mg of the product. MS m/e 1606.5, 1607.5, 1608.5 (M+1) [0228] Step 4: [0000] [0229] 30 mg of the product obtained from the previous step was dissolved in a solvent mixture of 3 ml of tetrahydrofurane and 3 ml of water, 7.8 mg of lithium hydroxide was added with stirring, the reaction solution was stirred for 4 hours, 18 mg of acetic acid was added to quench the reaction, the organic solvent was removed by a rotary evaporator, purification by preparative HPLC obtained 5.0 mg of the product, MS m/e 1592.2, 1593.2 (M+1) EXAMPLE 4 [0230] Compounds V16, V19, V26, V27, V30, V31, V32, V33, V67, V68 and the like were prepared according to the process as described in Example 1. EXAMPLE 5 [0231] [0232] Synthetic Procedure: [0233] Step 1: [0000] [0234] A 250 ml single necked flask was charged with 1.5 g of norvancomycin, which was dissolved in 80 ml of N,N-dimethylformamide at 80° C., 250 mg of the product obtained from Step 2 of Example 1 was added, followed by addition of 130 mg of sodium cyano borohydride in batch, and after addition, the reaction was performed for 2 hours, 5 ml of acetic acid was added and stirred for 0.5 hour, the reaction solution was poured into 100 ml of diethyl ether whereupon a solid precipitated, suction filtration was performed, the filter cake was stirred/washed with 40 ml of a solvent mixture of methanol and diethyl ether (1:3) followed by suction filtration, the crude product thus obtained was isolated by preparative HPLC to obtain 15 mg of the product. MS m/e 1736.5, 1737.5, 1738.5 (M+1) [0235] Step 2: [0000] [0236] 5 mg of the product obtained from the previous step was dissolved in a solvent mixture of 1 ml of tetrahydrofuran and 1 ml of water, 2.0 mg of lithium hydroxide was added with stirring, the reaction solution was stirred for 1 hour, 10 mg of acetic acid was added to quench the reaction, the organic solvent was removed by a rotary evaporator, purification by preparative HPLC obtained 3.5 mg of the product, MS m/e 1722.5, 1723.5, 1724.5 (M+1) EXAMPLE 6 [0237] Compounds V51, V52, V53, V54, V55, V57, V58, V59, V60, V68 and the like were prepared according to the process as described in Example 1. EXAMPLE 7 [0238] [0239] Synthetic Procedure: [0240] Step 1: [0000] [0241] A 500 ml single necked flask was charged with 3.1 g of 4-epi-vancosaminyl vancomycin, which was dissolved in 150 ml of N,N-dimethylformamide at 80° C., 500 mg of the product obtained from Step 2 of Example 1 was added, followed by addition of 250 mg of sodium cyano borohydride in batch, and after addition, the reaction was performed for 2 hours, 7 ml of acetic acid was added and stirred for 0.5 hour, the reaction solution was poured into 150 ml of diethyl ether whereupon a solid precipitated, suction filtration was performed, the filter cake was stirred/washed with 40 ml of a solvent mixture of methanol and diethyl ether (1:3) followed by suction filtration, the crude product thus obtained was isolated by preparative HPLC to obtain 7.8 mg of the product. MS m/e 1896.5, 1893.5, 1894.5 (M+1) [0242] Step 2: [0000] [0243] 5 mg of the product obtained from the previous step was dissolved in a solvent mixture of 1 ml of tetrahydrofurane and 1 ml of water, 2.0 mg of lithium hydroxide was added with stirring, the reaction solution was stirred for 1 hour, 10 mg of acetic acid was added to quench the reaction, the organic solvent was removed by a rotary evaporator, purification by preparative HPLC obtained 1.8 mg of the product, MS m/e 1881.5, 1880.5, 1879.5 (M+1) EXAMPLE 8 [0244] Compounds V61, V62, V63, V64, V65, V66, V69 and the like were prepared according to the process as described in Example 7.

The present invention provides a vancomycin derivative, and a preparation method and an application thereof. The vancomycin derivative of the present invention is obtained by introducing a glycerate moiety between a vancomycin derivative and a liposoluble modification group and has reduced liposolubility and improved water solubility, thereby reducing a side effect in the cardiovascular aspect.

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 13/373,600, now U.S. Pat. No. 8,589,376, the entire file wrapper contents of which are hereby incorporated by reference as though fully set out at length. In turn, U.S. patent application Ser. No. 13/373,600 claimed the benefit under 35 USC 119(e) of U.S. Provisional Application No. 61/458,442 filed Nov. 23, 2010 by Larry Deutsch, which is hereby incorporated by reference in its entirety. COPYRIGHT NOTICE [0002] A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. REFERENCE TO COMPUTER PROGRAM LISTING APPENDIX [0003] This application includes a computer program listing appendix submitted electronically which is identical to a computer program listing appendix submitted on compact disc with the parent application, U.S. patent application Ser. No. 13/373,600, now U.S. Pat. No. 8,589,376. FIELD OF THE INVENTION [0004] Broadly stated, disclosed in some embodiments is a method and apparatus for searching a community/classified posting service. BACKGROUND OF THE INVENTION [0005] Community/classified posting internet sites, on which users publish items for sale or make notifications and related web content available publicly, are popular. Tens of millions of people make tens of billions visits every month to these sites. Sections on the these sites may be devoted to jobs and resumes, housing, personals, items for sale, services, community issues, gigs and entertainment, and discussion forums. SUMMARY OF THE INVENTION [0006] In one embodiment of the invention, an application, commonly referred to as an “app,” is described. The app preferably runs on a mobile device, such as a mobile (cellular) telephone, a tablet device, a notebook computer, or a laptop computer. The purpose of the app is to connect to a community/classified posting site, search for items using user specified sections and keywords, parse information relating to the items, select relevant data, and display selected data in a format suitable for viewing on the particular device. In addition, the app optionally can run in the background, monitoring the site for newly posted information, and informing a user of a new item. This background search permits the user to respond in a rapid and timely way to an item as it becomes available, thus maximizing the user's chances of obtaining it. [0007] In more technical language, some embodiments of this app permit the user to subscribe to multiple concurrent channels of syndicated content published over the internet. A web services application programming interface (API) such as simple object access protocol (SOAP) is not required to be supported by the posting service. Instead, the method disclosed herein relies on a combination of web harvesting (e.g., markup language scraping) and parsing of syndicated content to extract and associate data from the posting service. The user receives notification of the content which is new since the previous time that the user accessed a channel. The user can select the frequency of checking for new content while the app conducts a background search. And the user can specify how far back in time to check for content. In addition, the user can specify a maximum number of changes to be presented. [0008] Such an app has to overcome numerous obstacles. For example, mobile devices may have batteries of limited capacity and life, may have limited size displays, and may have limited computing memory and power. In addition, there may be network and communication issues such as limited bandwidth and unreliable network connections. [0009] Referring to FIG. 10 , a sample device display shows how, in one embodiment, the user may set up a search, via the device, of items available on the posting site. Preferably, a graphic user interface for the device comprises menu selectors such as icons, tabs, and pull down widgets. [0010] Selector 1210 , as described above, notifies the user that new search results are available. A status indicator 1305 may indicate that the device is performing background searches and show the time interval between each search. [0011] One embodiment of the display shown in FIG. 10 is a selector 1310 that facilitates a search of the posting site. The selector 1310 brings up a screen and interface that shows search options and allows the user to enter parameters for an immediate search or a background search. [0012] Location selector 1320 brings up a screen (not shown) and interface that allows the user to narrow search results to items located within a specific geographic area. This location may be saved as a favorite accessible by selector 1370 . [0013] Favorites selector 1330 brings up a screen (not shown) and interface that may allow the user to select previously saved search requests, to access bookmarked search results, and to perform the following operations: Notify other users of search request or results via email, short messaging service (SMS) messages (e.g., text messages), or other communication modes Contact item poster via email, SMS messages, or telephone Respond to posting service Display a geographic map of the location of posted item Submit an auction bid [0019] The search keyword selector option 1340 allows the user to enter a keyword to narrow search results to those posted items whose descriptions contain the keyword. [0020] Search category selector option 1350 allows the user to enter a general category (such as “free,” “for sale,” or “for lease”) to narrow search results to those posted items within the category. [0021] Search sub-category selector option 1360 allows the user to enter a specific category (in this example “boats”) to narrow search results to those posted items within the sub-category. [0022] Favorite location selector 1370 allows the user to choose a geographic area previously saved by invoking selector 1320 (see above). Selector 1320 or 1370 optionally may access a current location of the user via global positioning satellite or other geo-location mechanism to use as a favorite. [0023] Filter selector option 1380 allows the user to further narrow search results to parameters (in this example minimum price and maximum price) within a range or other specifications. [0024] Search selector 1390 allows the user to initiate an immediate search. A screen displaying results, as shown in FIG. 11 in one embodiment, may automatically appear. [0025] View results selector 1392 allows the user to view the results of a background search. [0026] Search preferences selector 1394 directs the user to one or more screens (not shown) that allow the user to display and edit various search parameters such as, in some embodiments: Enable or disable display of thumbnails on a result screen (such as shown in FIG. 11 ) Specify a maximum number of search results to return Specify a look-back time interval (e.g., do not return items posted before a specified time) Enable or disable background searches for newly posted items Enable or disable visual, audible, or tactile forms of notification of new results Set a time interval between each background search [0033] The time between search intervals is a trade-off, in some embodiments, between receiving search results as soon as possible after postings are listed and extending battery life of the device. The shorter the period between search intervals, the larger the drain on a battery. However, the longer the interval, the less likely the user will be able to submit a quick enough response to obtain a posted item. Obviously, this tradeoff not a factor for plugged in devices. [0034] Another selector, a clear saved data option (not shown), may direct the user to one or more screens (not shown) that allow the user, in some embodiments, to perform one or more of the following functions: Delete background search results Delete favorite search requests Delete preferred locations Delete bookmarks and/or bookmarked results Clear web cache [0040] Referring to FIG. 11 , a sample device display shows how, in one embodiment, the app may display search results, gathered from a posting site, to the user. [0041] Notification selector 1210 , when displayed, indicates to the user that new search results are available on the device. This app permits background searches to be performed at periodic intervals while other app's and functions are running on the device. Selector 1210 may appear on a status line while the user is running another app, while using the device for a phone call, or while the device is in idle mode. In addition to a visual selector, the user may be notified of new search results by a sound (e.g. a ring tone) or a vibration, for example. Upon receiving selector 1210 , the user may review updated search results. [0042] Optional image thumbnail 1220 displays a photograph, picture, or drawing on the device of an item (e.g. a good or service), offered on the posting site, selected from a user specified category and/or keyword. Reasons that the thumbnail 1220 may not be shown include lack of a photograph, picture, or drawing of the item on the posting site, a user decision not to show thumbnails on the device (which can reduce the size of data to be communicated from the posting site to the device and save memory on the device), image is too big to download, target website temporary not responding, temporary loss of communications, and lack of relevance of a thumbnail to the requested information. [0043] Contents 1230 include details of the posted item. Specifically, contents 1230 may include title of the item, date and time posted, price, description, location, and condition. The most relevant details may include a short summary description and date. By “clicking” on the details, the user may select the item to display a full posting. The user may scroll through multiple postings, if they exist. [0044] Aspects of this specification, comprising routines and data structures, in addition to contributing to the operation of the app, are relevant to other types of apps. One embodiment of the invention, included in Appendix A, comprises Java and XML user interface specifications. BRIEF DESCRIPTION OF THE DRAWINGS [0045] The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself however, both as to organization and method of operation, together with objects and advantages thereof, may be best understood by reference to the following detailed description of the invention, which describes certain exemplary embodiments of the invention, taken in conjunction with the accompanying drawings in which: [0046] FIG. 1 is a high level diagram of a method implementing the invention according to one embodiment. [0047] FIGS. 2A and 2B combined is a diagram of a method of performing a background search of a community/classified posting service. [0048] FIGS. 3A and 3B combined is a diagram of a method of process retry logic for handling battery and communication error problems. [0049] FIGS. 4A and 4B combined is a diagram of an asynchronous thread to perform multiple search requests. [0050] FIGS. 5A , 5 B and 5 C combined is a diagram of a procedure to execute a single search request. [0051] FIGS. 6A and 6B combined is a diagram of a thread to perform an markup language search of the posting service. [0052] FIGS. 7A , 7 B, 7 C and 7 D is a diagram of a thread to perform an syndicated content search of a posting service. [0053] FIGS. 8A and 8B is a procedure to store the search results in a table. [0054] FIG. 9 is a block diagram of an apparatus configured to perform features of the invention according to one embodiment. [0055] FIG. 10 is a diagram of a user interface for controlling the apparatus to perform a search of the posting service. [0056] FIG. 11 is a diagram of a user interface to display and scroll through search results. [0057] FIG. 12 is a block diagram of a system configured to execute some embodiments of the invention. DETAILED DESCRIPTION OF THE INVENTION [0058] While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail specific embodiments, with the understanding that the present disclosure is to be considered as an example of the principles of the invention and not intended to limit the invention to the specific embodiments shown and described. In the description below, like reference numerals are used to describe the same, similar or corresponding parts in the several views of the drawings. [0059] As used in this application, the generic term “content reference” includes the concept of uniform resource locator (URL) and equivalents. [0060] As used in this application, the generic term “markup language” includes the concept of hyper-text markup language (HTML) and equivalents. [0061] As used in this application, the generic term “syndicated content” includes the concept of RDF Site Summary (RSS) sometimes known as “really simple syndication” and equivalents. “RSS” is a family of web feed formats used to publish frequently updated works. RSS is a web content syndication format that is a dialect of XML 1.0. The RSS 2.0 specification was released through Harvard under a Creative Commons license on Jul. 15, 2003 which is available on the internet at the cyber law Harvard RSS website. [0062] As used in this application, the term “data store” includes but is not limited to the concept of a database. A data store may be any type of information depository known in the art accessible by data processing apparatus. [0063] Referring initially to FIG. 9 , a system is shown which includes a digital processing apparatus 1000 . This system is preferably a mobile device (such as a cellular telephone, notebook computer, tablet computer, or laptop computer). The example apparatus in FIG. 9 includes provision for input power 1010 (such as a battery and power management IC), application processor(s) 1030 , RAM memory 1090 , and internal memory 1100 (e.g., non-volatile memory such as flash memory, hard drive, CD-ROM drive, or DVD drive). Communications may be provided by optional network adapter 1085 , and/or optional Wi-FI adapter 1080 , to a local area network 1120 or to a point-to-point network 1130 . In addition, optional connectivity to cellular network 1110 may be provided via baseband processor 1020 (a CPU that manages cellular network 1110 communications), transceiver 1050 which handles the broadcast and reception of radio signals with network or subscriber equipment, and one or more power amplifiers 1070 which increase signal power up to levels required for wireless communication. [0064] Electronic visual display 1060 typically comprises an LCD touch screen and preferably supports graphics. Data input may be through one or more of the following agencies: keyboard 1040 (soft or hard), touch interface or pointing device 1045 , voice (not shown), disk storage (optionally comprising internal memory 1100 ), local area network 1120 , point-to-point network 1130 , and cellular network 1110 . [0065] One or more features of the computer as shown may be omitted while still permitting the practice of the invention. For example, apparatus pointing device 1045 , such as a mouse, is not required where the apparatus 1000 is a cellular telephone. [0066] FIG. 12 is a block diagram of a system configured to execute some embodiments of the invention. Digital processing apparatus 1000 includes operating system 1480 . Apparatus 1000 also comprises an application processor 1030 a which in turn comprises control logic 1410 . Operating system 1480 is in communication with data store 1475 (which may include but is not limited to a database). In addition, operating system 1480 is in communication with content parsing logic engine 1465 . Data store 1475 is in communication with query engine 1470 , such as a SQL based query system. In turn, query engine 1470 is in communication with content parsing logic engine 1465 . [0067] Content parsing logic engine 1465 generates a content reference 1420 based on user selected and/or defined preferences (e.g., parameters saved in data store 1475 ). Then engine 1465 uses reference 1420 in executing a first query on posting site to retrieve markup language content 1425 . Next, the engine 1465 generates map 1440 where posting site item identifiers 1450 are mapped to item data 1460 . The engine then uses content reference 1420 in its execution of a second query of the posting site to retrieve syndicated content 1430 . This content is used to generate information to be included in appropriate item data 1460 locations resulting in a modified map 1440 . [0068] The content parsing logic engine passes the modified map 1440 to the query engine 1470 which in turn stores these results in data store 1475 , if the search is a background search. Otherwise, if the search is a foreground search, these results are displayed to the user. [0069] The flow charts herein illustrate the structure of the logic of the present invention as embodied in computer program software. Those skilled in the art will appreciate that the flow charts illustrate the structures of logic elements, such as computer program code elements or electronic logic circuits which function according to this invention. Manifestly, the invention is practiced in its essential embodiment by a machine component that renders the logic elements in a form that instructs digital processing apparatus 1000 (that is, a computer) to perform a sequence of function steps corresponding to those shown. [0070] Logic elements may be contained on a computer program product which includes but is not necessarily limited to a disk, volatile or non-volatile memory, flash memory, and ROM for storing program modules. Program modules may comprise a computer program that is executed by processor(s) 1030 within the apparatus 1000 as a series of computer-executable instructions. In an illustrative embodiment of the invention, the computer-executable instructions may be lines of compiled Java code. [0071] FIG. 1 is a high level view of a foreground and background search method. Step 110 is a scheduler that decides which action to perform. Options include performing a foreground or background search at step 114 , accepting user requests at step 146 , or entering a sleep state 134 prior to running a search. [0072] Step 114 is a high level representation of a method for initiating a search (shown in detail in FIGS. 2A and 2B ). At step 118 , if new search results are found, they are processed. Otherwise, proceed to step 130 which in turn proceeds to sleep state 134 or to a wait state for user input at step 146 . [0073] If there are new results at step 118 , record the results in a table at step 122 that executes the steps 804 to 844 (returning to step 122 at step 848 ) (see FIGS. 8A and 8B and accompanying description). Then the user is notified of new results at step 126 that executes the steps 440 to 456 (returning to step 126 at step 460 ) (see FIG. 4B and accompanying description). This notification, in some embodiments, can be a display of a selector in a status area, a sound, a vibrate alarm, or notification “widget” on the user's home screen. As defined in the internet online service Wikipedia: “In computer programming, a widget (or control) is an element of a graphical user interface (GUI) that displays an information arrangement changeable by the user, such as a window or a text box. The defining characteristic of a widget is to provide a single interaction point for the direct manipulation of a given kind of data. In other words, widgets are basic visual building blocks which, combined in an application, hold all the data processed by the application and the available interactions on this data.” [0074] Some embodiments of this invention display search results via a widget on a pop up window while the user is executing other applications. [0075] Upon exiting sleep state 134 (when it is time to search), the process proceeds to step 114 . Otherwise a decision is made to either proceed to sleep state 134 again or to wait state step 146 . Upon exiting the wait state step 146 , it is determined at step 148 whether there is a new user request. If there is a request, the process proceeds to sleep state 134 to wait for the next time to search. Otherwise, the process may proceed either to wait again for user input at step 146 or to sleep state 134 for the next time to search. [0076] In FIGS. 2A and 2B , step 114 is detailed. At step 204 , if the search service is enabled proceed to step 208 to continue with the search. Otherwise, return to the sleep state 134 . At step 208 , a list is obtained of search request objects from a data set. These are searches and associated criteria input by the user. Typically, search request objects would be stored in a relational database, but this is not required. A search request object comprises: 1. A short description of the request 2. The content reference for the request 3. Filters for the search (e.g. price ranges, age limits, square footage, etc.) 4. Search category (e.g. for sale, housing, services, etc.) 5. Auto search enabled flag (true if the search should be run in the background, false otherwise) 6. Last hit time (calendar time of the most recent match from the previous search) 7. Identifier for the last item that was successfully matched. The identifier can be a content reference or other string that is unique for the posting service. After completing step 208 , a decision is made at step 212 whether search request objects are found. If not, the process proceeds back to sleep state 134 . If search requests objects are found, at step 216 the process records time since last boot in a data store. [0084] The data store can be on a file system, or some other data storage mechanism. The data can be represented a simple name-value pair association. A battery operated device can go into “Deep Sleep” mode to save battery life. The time since last boot is the absolute amount of time since the device was lasted powered on, and includes the time that the device was in Deep Sleep mode. This time is used to determine when to schedule the service to run, and is used in process retry logic step 240 (shown in detail in FIGS. 3A and 3B ). [0085] The process at step 220 obtains polling time interval, according to user preference, from the data store. The polling interval is specified by the user as the number of hours and seconds in which to periodically run the automatic searches. [0086] The process at step 224 obtains an error count. The error count is the number of failed attempts to contact the server data feed since the last successful connection. This is used in the process retry logic at step 240 . [0087] The process determines at step 228 the ability of the device to connect to the network. The network comprises the cellular network 1110 , the local area network 1120 , the point-to-point network 1130 . [0088] The process at step 232 reads battery status from the device. This would typically be the percentage of maximum capacity remaining on the device. [0089] The process at step 236 decides if the device can connect to the network. If not, the process performs the process retry logic at step 240 . Also the process performs the process retry logic step 240 if the battery capacity is insufficient. Battery sufficiency can be determined by processing the charging status and the capacity remaining on the device. The result of a step 240 operation determines when to the schedule the next attempt to connect to the network and execute background search processing. [0090] If the process at step 236 decides that the device can connect to the network, the process proceeds to reset error count at step 244 . The error count is reset to a value, such as zero, which indicates that no errors are outstanding. The value is saved in a data store for the next time that the background search is executed. [0091] The process next starts an asynchronous thread at step 248 executing the steps from step 404 to 456 (returning to step 248 at step 460 ) (shown in more detail in FIGS. 4A and 4B ). Step 248 will execute the background search. [0092] FIGS. 3A and 3B show the process retry logic executed by step 240 . The goal of the process retry logic is to adjust the retry time, taking into account a user's preferred polling interval and the number of consecutive connection errors. Cellular communications can be very unreliable, depending on the user's location and radio coverage. An unsophisticated technique of repeatedly attempting to connect at set time intervals, especially at short time intervals, is wasteful of battery capacity. Also, abandoning attempts to connect after a limited number of times may miss an opportunity to reconnect when coverage is available. [0093] Step 304 checks for low battery. If battery is low, perform low battery processing at step 308 . If not, perform process retry logic (steps 312 to 356 ) based on polling interval and error count. [0094] At low battery processing step 308 , perform low battery processing based on charging status and capacity remaining. For example, if battery capacity is less than 50% and polling interval is less than one hour, the next attempt might be delayed until twice the polling interval. Alternatively, a lookup table can be configured with the rows representing battery life, and the columns representing the retry interval. Each cell could contain a rule determining when to retry the next search. [0095] If battery is not low, perform get polling interval step 312 ; read polling interval user preference from a data store such as a database. [0096] Step 316 determines if polling interval is less than a first threshold. For example, the first threshold might be 20 minutes [0097] Typically, server data feed is only updated at a limited time frequency (for example, 15 minutes). It would be wasteful to try more frequently than a data feed update frequency at which the first threshold is approximately set. Thus, if the user's preferred polling interval is less than the first threshold, retry at the expiration of the user's next preferred polling interval. [0098] At step 316 , it is determined if the polling interval is less than the first threshold (e.g., the polling interval is less than 20 minutes). If it is, proceed to step 352 where error count is reset and saved in a data store. Then proceed to step 356 and run the service at its next regularly scheduled polling interval. Next proceed to step 134 . [0099] Otherwise, if at step 316 the polling interval is greater than or equal to the first threshold, proceed to step 320 . [0100] At step 320 , if the polling interval is less than a second threshold (e.g., less than 60 minutes), but greater than the first threshold, proceed to step 340 to check the error count else proceed to step 324 . If at step 340 , the error count is >=n 2 (e.g. n 2 =1), the number of retry attempts has been exceeded. n 2 is also referred to as “first constant” in this application. Then in this case, reset the error count at step 352 , save in the data store, also at step 352 , and run the service polling interval at step 356 . Then proceed to step 134 . [0101] If the error count is less than n 2 at step 340 , set the error count to 1 plus the previous error count and save the error count in the save data store at step 344 . Proceeding to step 348 , the service is rescheduled to run at an interval that is a fraction of the polling interval (e.g. the fraction being 10 minutes). Then proceed to step 134 . [0102] If, at step 320 , the polling interval is greater than or equal to the second threshold proceed to step 324 . An error count less than or equal to n 1 (e.g. n 1 =0), n 1 being less than n 2 , means that insufficient retries have been attempted. n 1 is also referred to as “second constant” in this application. In this case, proceed from step 324 to step 344 , where the error count is incremented and saved in the save data store. Proceeding to step 348 , the service is rescheduled to run at an interval that is a fraction of the polling interval (e.g. the fraction being 10 minutes). Then proceed to step 134 . [0103] At step 324 , if the error count is greater than n 1 , proceed to step 328 . At step 328 , test whether number of retry attempts is greater than or equal to n 3 , n 3 being greater than n 1 (e.g. n 3 =1). n 3 is also referred to as “third constant” in this application. If the error count is greater than n 3 , proceed to reset the error count at step 352 , save in the data store (also at step 352 ), and run the service polling interval at step 356 . Then proceed to step 134 . [0104] At step 328 if the error count is less than n 3 , set the error count to 1 plus the previous error count and save in the data store at step 332 . Proceed to step 336 where the service is rescheduled to run at some fraction (e.g. 50%) of the polling interval. Then proceed to step 134 . [0105] FIGS. 4A and 4B show a search thread that is an asynchronous task running in the background. [0106] At step 404 , if the alert service is disabled, terminate the alert at step 420 and return at step 422 . If the alert service is enabled than proceed to step 408 to get a list of search request objects from a data store. [0107] At step 412 , if no search request objects were found in the data store, proceed to step 420 to terminate the alert service and return to the caller at step 422 . [0108] If, at step 412 , search request objects were found in the data store, proceed to step 416 and initialize the autoHits count to zero. The autoHits count is the number of postings that are found by executing all of the search requests. [0109] Next proceed to iterate steps 424 , 428 , and 432 . At 424 , determine if more search requests are outstanding. If not, terminate looping and proceed to step 436 . Otherwise, proceed to step 428 where a search for a current search request is performed. Then increment at step 432 the autoHits by the number found from the search. Next, the process loops back to step 424 . [0110] The search and the user interface process are asynchronous, so the user can look at an autoHits table (see FIGS. 8A , 8 B, and 8 C and accompanying description), while the search is in progress. Therefore at step 436 , a count (sumWaitingForUser) of the current unviewed autoHits is queried from the data store. Then proceed to steps 440 to 456 where the user is notified of search results. The user can be notified during background search or when the app is running in the foreground. This can be accomplished by adding a notification selector in the mobile status area, or displaying a notification widget on the user's home screen. [0111] At step 440 , a check is made to determine if the number of autoHits from the previous search iteration (steps 424 , 428 , and 432 ) is greater than zero. If the number is not greater than zero, proceed to step 452 . At step 452 , determine if the sumWaitingForUser is equal to zero. If the sumWaitingForUser is equal to zero, cancel at step 456 any user notification currently displayed. This can be accomplished by removing the notification selector in a status area, or by removing a notification widget in the user's home screen. Next, return to the caller at step 460 . If, at step 452 , the sumWaitingForUser is not equal to zero, return to the caller at step 460 without canceling the user notification. [0112] If, at step 440 , the number of autoHits is greater than zero, the process proceeds to step 444 where a user notification of sumWaitingForUser results is displayed. Then at the next step, step 448 , a user interface is updated if currently visible. After step 448 , at step 460 , the process returns to the caller. [0113] FIGS. 5A , 5 B, and 5 C shows the sequence of steps performed at search step 428 . [0114] The perform search 428 sequence of steps is the main procedure for executing a single search request. It can run automatically in the background at periodic time intervals, or in the foreground at the request of the user. It accepts as input a SearchRequest object defined by the user, and returns the number of resulting search hits. If search results are found, they are stored in the autoHits Table for retrieval and display by the user. [0115] A problem to be solved by some embodiments of the present invention is that posting services publish information partly in markup language format and partly in syndicated content format. [0116] The posting service can return posted items in both markup language and syndicated content formats. The data associated with posted items may be distributed across both formats. Some embodiments of this invention apply user-specified criteria to perform searches of posted items, to extract data published in dissimilar formats, such as markup language and syndicated content formats, to integrate the data into displayable results, and to notify the user of the results preferably on a mobile device. [0117] The benefit of parsing markup language content, in addition to syndicated content channel, is that additional data can be extracted and associated with a posted item that is not available in syndicated content alone. For example, the posting service may host an image for a posted item that is uploaded by the user, and represented in the markup language content as a content reference. By associating this image content reference with the posted item in the syndicated content channel, time consuming parsing of syndicated content is not required to display an image thumbnail. [0118] An example of a posted item, as presented to the user, is shown in FIG. 11 . An item includes a posting date and time, a short description of merchandise contents 1230 , and a content reference which the user can select to display detailed web content. This invention also provides a mechanism to parse item data across multiple content formats in order to generate efficiently the image thumbnail 1220 for display, preferably on a mobile device. [0119] A “hit” is defined as a match between the search criteria specified by the user in the SearchRequest object, and a single item extracted from a list of items returned from the community/classified posting service. A match can be made based on one or more of the following criteria: Keyword Search category (e.g. for sale, jobs, services) Search subcategory (e.g. boats, cars, accountant) Time range Filters supported by service (e.g. price ranges, age limits, square footage, etc.) [0125] The following input variables, which are members of the SearchRequest object, are utilized by this procedure: 1. searchUrl—content reference to retrieve individual posting results. 2. lastHitTime—Calendar time of the most recent match from the previous search 3. lastHitId—Identifier for the last item that was successfully matched. The identifier can be a content reference or other string that is unique for the posting service. 4. filters [0130] A high level description for performing search 428 is as follow: 1. Apply filters to generate markup language search request (apply filters step 504 ) 2. Determine stop criteria step 508 for searching 3. Perform markup language search to extract a postedItemMap. The postedItemMap is a map of posting identifiers and associated posted item data which is data extracted from posting data element. The posting data element contains a posting identifier and data associated with a posting such as image content references. Other posting data element content might include an item price, a posting time, an item description, and a flag that indicates the availability of images external to the service. 4. Generate syndicated content search request 5. Perform syndicated content search until stop criteria is satisfied 6. Record hits in AutoHits table, if any. Embodiments of this invention also include a mechanism on a mobile device to store a limited number of the most recent hit results to a data store table, for future presentation to the user. [0137] At step 504 , a search request is constructed by applying the input filters to input content reference, and formatting a request for markup language content. The input content reference comprises the domain name of the search service website and any additional path and query parameters needed to execute the search. The input content reference is specific to the service being searched. [0138] At step 508 , determine the search stop criteria as described in the following pseudo code: [0000] // The variables used by the parsing threads to determine when to stop the search are: // 1. maxHits - User specified preference for the maximum number of search results to return // 2. lastHitId - Identifier of the most recent posting that was found during the previous search. // The background search only returns search results that haven't been made available to the // user from previous background searches. // 3. lookBackTime - Calculated calendar time that indicates how far back in time to search lookBackTime = −1 // Default to unlimited look back time if (userLookBackInterval specified by user) { // Subtract userLookBackInterval from current time lookBackTime = currentTime − userLookBackInterval if (lastHitTime > lookBackTime) { // We received a hit more recent than the user specified // look back interval. Use the more recent time lookBackTime = lastHitHime // Subtract a small amount of time from the look back time // to account for any overlaps or posting errors lookBackTime = lookBacTime − 5 minutes } } [0139] Parsing thread 512 is a sequence of steps (shown in detail in FIGS. 6A and 6B ). Start an asynchronous thread that will execute the markup language search, and then execute sleep loop until the timeout has expired or the search is finished. [0140] Next, steps 516 , 520 , and 524 are iterated. At step 516 , decide whether parsing is completed. If completed, proceed to the step 532 , exiting the loop. If not done parsing, proceed to step 524 to determine if the parsing timeout period has expired. If the timeout period has not expired, enter a wait state at step 520 and subsequently return to the start of the loop. If the timeout period has expired at step 524 , exit the loop, kill the markup language parsing thread at step 528 , and proceed to step 532 . [0141] At step 532 , a posted item map is returned from the markup language parsing thread. It comprises the posted item identifications and associated posted data, Examples of posted data include a description, a price, or an image content reference for the item being posted. [0142] At step 536 , a syndicated content search request is initiated by formatting a request for syndicated content. The request is specific to the service being searched, but it might be constructed by appending path and query information to the input content reference. [0143] At step 540 , a syndicated content parsing thread sequence of steps (shown in detail in FIGS. 7A , 7 B, 7 C, and 7 D) is started. Start an asynchronous thread that will execute the syndicated content search, and then proceed to the sleep wait state until the timeout has expired or the search is finished. Inputs to the syndicated content parsing thread comprise the syndicated content stop criteria and the posted item map. The posted item map comprises the results of the markup language search. [0144] Next, steps 544 , 548 , and 552 are iterated. At step 544 , decide whether parsing is completed. If completed, proceed to step 560 exiting the loop. If not done parsing, proceed to step 552 to determine if the parsing timeout period has expired. If the timeout period has not expired, enter a wait state at step 548 and subsequently return to the start of the loop. If the timeout period has expired at step 552 , proceed to kill the markup language parsing thread at step 556 and exit the loop, proceeding to step 560 . [0145] At step 560 , it is determined if there are any search results. If there are no search results, set number of hits (numberOfHits) to 0 and return the result at step 578 . However, if there are search results, calculate the number of hits as the count of the number of RdfItems returned from the syndicated content parsing thread from step 540 . [0146] RdfItems contains the following data: 1. title—Short description which can be presented to the user 2. link—content reference to posted content 3. description—syndicated content description parsed from the posting 4. location—Optional geographic location of item posting 5. imageUrls—Candidate list of content references which can be used for thumbnail generation 6. time—Time item was posted [0153] If the search results are greater than 0 at step 568 , calculate the number of results (numberOfHits) by determining the count of RdfItems. [0154] Update SearchRequest table at step 570 . The following input variables, members of the SearchRequest object, are utilized by this step 570 : 1. searchUrl—content reference to retrieve individual posting results. 2. lastHitTime—Calendar time of the most recent match from the previous search 3. lastHitId—Identifier for the last item that was successfully matched. The identifier can be a content reference or other string that is unique for the posting service. 4. filters [0159] The SearchRequest table is updated to reflect the most recent hit, so future searches do not return the same results. The identifiers (lastHitId) and time (lastHitTime) of the most recent post found are updated in the table. [0160] Convert RdfItems at step 572 . The RdfItems returned from syndicated content parsing thread are converted to AutoHit objects, so they can be stored in the AutoHits table. [0161] An AutoHit object comprises: 1. title—Short description which can be presented to the user 2. link—content reference to posted content 3. location—Optional geographic location of item posting 4. imageUrls—Candidate list of content references which can be used for thumbnail generation 5. time—Time item was posted 6. isNew flag—True if the user has not yet viewed the item, false otherwise. [0168] In this case, because the items have not been view by the user, the isNew flag is set to true. [0169] Save hits step 574 executes steps 804 to 844 (returning to step 574 at step 848 ) (shown in detail in FIGS. 8A and 8B ). Save the hits in the AutoHits table. [0170] The invention includes a mechanism to store a limited number of the most recent hit results to a data store table for future presentation to the user. A list of AutoHit objects is passed to this procedure. The list contains the search results, from most to least recent. Return numberOfHits, step 578 . [0171] FIGS. 6A and 6B show an markup language parser. This an expansion of the steps referred to by step 512 . [0172] At step 604 , get a character reader in order to read an markup language input stream from the content reference. Next, begin iterating steps from step 608 to step 636 . At step 608 attempt to read the next line from the markup language input stream. The end of the stream would typically be indicated by a negative number of bytes returned or by reading an End Of File character. [0173] Step 612 checks to determine if there are more lines to read or data to process. If the last line has been read, return. Otherwise, read a next posting data element (defined above) at step 616 . [0174] If the posting data element is not contained on a separate line, this could be implemented by reading additional lines from the 10 stream. An alternative approach would be to read the next match of a regular expression matcher. [0175] Step 620 determines if there is more markup language data; i.e., if there are additional posting data elements. If there are no more markup language data to process, return the postedItemMap to the caller at step 640 . The determination of whether there is more data to process depends on the markup language content provided by the service. One implementation would utilize a regular expression matcher to extract posted items from the markup language. If there are no more matches, the processing is completed. [0176] If, at step 620 , there are more data to process, proceed to step 624 where the posted item is extracted from markup language content. The mechanism to parse the data depends on the format of the markup language content provided by the service. One approach would utilize string matching to extract the relevant data. Another approach would use regular expression matching. A posted item identifier must be extracted from the data in order to associate this posting with the data in the syndicated content channel. [0177] At step 628 , if the number of posting items found is equal to or exceeds the maxHits stop criterion, return at step 640 . If instead the number of posting items is less than the maxHits stop criterion, continue processing at step 630 . [0178] At step 630 , if the search is being performed in the foreground, all posted results are desired and proceed to step 636 . Otherwise, the search is being performed in the background and the process proceeds to step 632 to perform a look back time (lookBackTime) check. The check for the lookBackTime at step 632 determines if posting time is available in the posting data element. If it is available and is older than the lookBackTime stop criteria, defined above, the search is completed and proceed to return posted item map to the caller at step 650 . If posting time is not available, or the posting time is more recent that the lookBackTime, proceed to step 636 . [0179] At step 636 , add the posting identifier and posted item to the postedItemMap, and continue with the search by looping back to step 608 . [0180] FIGS. 7A , 7 B, 7 C, and 7 D detail the syndicated content search (parsing) thread referred to at step 540 . [0000] The syndicated content Parsing Thread parses service contents resulting from the submission of syndicated content search request. A reader to the syndicated content stream is obtained from the search request, and each posted item is parsed until the search stop criteria (step 508 ) is satisfied. The stop criteria can be applicable to both the markup language search ( FIGS. 6A and B) and the syndicated content search ( FIGS. 7A , 7 B, 7 C, and 7 D). Since an syndicated content feed contains structured XML content, a standard XML parser can be utilized to parse the document. A representative service might post an syndicated content channel as follows: [0000] <channel> <title>Community/classified posting service</title> <link>http://samplepostingservice.com</link> <description>This is a sample channel for a posting service</description> <item> <title>Cape dory 25 - $3500</title> <link>http://annapolis.samplepostingservice.com/forsale/boats/<link> <pubDate>2011-11-06T14:41:19-05:00</pubDate> <description> <![CDATA[<p>1978 Cape Dory ready to sail away</p>]]> </description> </item> </channel> [0181] The syndicated content parsing thread is initialized with the postedItemMap obtained as a result of the markup language parsing (step 512 ). The postedItemMap is a map of posting identifiers and associated posted item data. The syndicated content parsing thread returns a list of RdfItems, which can be converted to AutoHit objects for storage in the AutoHits table. [0182] At step 704 , get a character reader in order to read an syndicated content input stream from the content reference. A search request is constructed by applying the input filters to the input content reference, and formatting a request for syndicated content. The input content reference comprises the domain name of the search service website and any additional path and query parameters needed to execute the search. The input content reference is specific to the service being searched. [0183] Initialize Parser at step 708 . Use a standard XML parser, such as a pull parser. [0184] Next iterate the steps from step 712 to step 764 . First, at step 712 , check if the end of the XML document has be reached. If the end of XML document has been reached, exit loop to step 768 for post-processing of the RdfItems. Otherwise, continue processing at step 716 . [0185] At step 716 , a determination is made if parsing of the posted items is completed. If parsing is completed, exit loop and proceed to step 768 for post-processing of the RdfItems. Otherwise, continue processing to step 720 to parse the next posted item. See above for an example of the syndicated content format to be parsed. Data items to be parsed include: 1. title—Short description which can be presented to the user 2. link—content reference to posted content 3. description—A more detailed description of the posting. This can include markup language content for display on a web page 4. date—The date the item was posted [0190] Proceed to step 724 to determine if the number of items parsed so far is greater than or equal to maxHits. If the number of posting items found equals or exceeds the maxHits stop criteria, exit loop to step 768 for post-processing of the RdfItems. Otherwise, continue processing at step 732 . [0191] If searching in the background at step 732 , the lastHitId and lookBackTime stop criteria will be applied and proceed to step 736 . If searching in the foreground, ignore the stop criteria and proceed to step 744 . [0192] At step 736 , if the lastHitId matches the identifier from the parsed item, exit loop to step 768 for post-processing of the RdfItems. Otherwise, continue processing at step 740 . [0193] At step 740 , if a posting time was extracted from the posted item and the item that is currently being parsed is older the lookBackTime stop criteria, exit loop to step 768 for post-processing of the RdfItems. Otherwise, proceed to step 744 . [0194] At step 744 , use the identifier of the posted item as a lookup key to the postedItemMap. If an entry exists, the same item was previously processed from the markup language processing thread; proceed to step 748 . At step 748 , if the item previously processed from the markup language processing thread contains an image content reference, it is not necessary to continue to parse additional content. This saves considerable processing in locating a suitable image content reference from which to generate a thumbnail. If an image content reference is not available, syndicated content description element will be searched. [0195] If an entry does not exist at step 744 , go to step 752 to parse the posted item description for image content references. The syndicated content description data can contain markup language content that was posted by the service user. The content can be parsed to find a list of candidate images that would make suitable thumbnails. Images that would not make suitable thumbnails are not added to the list. When the AutoHit items are displayed for the mobile user, this reduces the processing needed to display a thumbnail. The parsing procedure at step 752 to find a list of candidate image content references is described in the following pseudo-code: [0000] Create regular expression matcher to locate image links Apply regular expression to markup language content while there are more matches and number of matches < MAX_THUMBNAILS_TO_TRY { Get next link from matcher Extract image resource name from link if resource name indicates image would make a bad thumbnail { // e.g. spacer.gif, blank.gif, etc. continue } if link is not a valid content reference { continue } Extract width and height attributes from image tag if width and height are available { Calculate aspect ratio of image if aspect ratio is too big or too small { // The image is most likely some type of // formatting element, such as a spacer - ignore continue } } Add image to list of candidates } return candidate list of images [0196] If at step 756 , one or more candidate images were found in syndicated content description, the candidate images are stored in the RdfItem, at step 760 , which is then added to the return list, at step 764 . If one or more images were not found at step 756 , bypass step 760 and proceed to step 764 . At step 764 , add RdfItems to a return list and loop back to step 712 . [0197] Referring back to step 748 , if an image content reference is found proceed to step 760 (described above). If an image content reference is not found at step 748 , execute the steps described in step 752 (see above). [0198] Some of the RdfItems in the return list may not have image content references associated with them. This can occur when both the markup language parser and syndicated content description parser fail to find candidate images. In this case, the contents pointed to by the link in the RdfItem will also be searched for candidate images. As a performance optimization, the links to search will be grouped into small batches so they can be executed concurrently. Typically, mobile devices can only process a few concurrent connections at a time. This number can be optimized for the specific device and communications network being utilized. [0199] To accomplish the above, post-processing is conducted starting at step 768 (routed to there from steps 712 , 716 , 724 , 736 , and 740 ). Step 768 is the start of a loop: steps 768 , 772 , 780 , 784 , and 788 . At step 768 , get a next batch of RdfItems which do not contain content references. This can be accomplished by conducting a linear search through the RdfItems to find items without image content references. [0200] At step 772 , if there are no more batches to process, exit the loop and return the list of RdfItems to the caller at step 776 . Otherwise, at step 780 start one ImageParser thread for each RdfItem in the batch. The link in each RdfItem represents a detailed posting by a service user. The contents pointed to by the link can be parsed for a list of candidate thumbnail images. One ImageParser thread will be created for each link in the batch of RdfItems. The ImageParser thread will open an IO reader from the link content reference, and then utilize the method specified in parse syndicated content description step 752 to parse image links. [0201] At step 784 , if all the threads in the current batch are not done, proceed to step 788 to wait. Otherwise, proceed to step 768 to get the next batch to process. The completion of the threads can be coordinated by a countdown latch object, or other similar thread synchronization mechanism. [0202] Steps 574 and 122 utilize the logic shown in FIGS. 8A and 8B . [0203] At step 804 , a data store transaction begins. This procedure assumes the existence of a transactional data store on the device. The data store operations in this procedure should be atomic, and a mechanism should be available to roll back the transactions if a failure occurs. [0204] At step 808 , count the number of rows (numOfRows) in the AutoHits Table, by executing a query against the data store. [0205] At step 812 , the number of open slots (openSlots) is calculated by subtracting the numOfRows from a capacity of the AutoHits Table. Capacity is the maximum number of rows that the table can grow to. The capacity is a tradeoff between memory utilization on the mobile device and the number of prior hits available to the user. [0206] At step 816 , a count of the number of AutoHits (nRecords) being inserted into the table is determined from the list of AutoHit objects passed into this procedure. [0207] At step 820 , determine if nRecords>capacity of the AutoHits table. If the number of records being inserted into the table is greater than the capacity, proceed to step 832 which deletes all of the existing records in the AutoHits table. Then proceed to step 836 . [0208] At step 836 , the number of records being inserted is greater than the capacity of the table, so the oldest records can't be accommodated. The list of records being inserted is ordered from most to least recent, so the excess number of records (capacity−nRecords) is removed from the end of the list. Then proceed to step 840 . [0209] If, at step 820 , the number of records being inserted into the AutoHits table is less than or equal to the capacity of the AutoHits table, proceed to step 824 to determine if nRecords is greater than openSlots. [0210] At step 824 , if nRecords is greater than openSlots, proceed to step 828 to make room in the AutoHits table by removing the oldest records. The AutoHits Table is ordered from the least recent postings to most recent. Additional room is made in the table by removing the oldest entries at the top, thereby creating room to add the newest entries at the bottom. This is done without increasing the capacity. The number of records to remove is calculated by (nRecords−openSlots). This number of records can be removed from the beginning of the table by executing a query. After executing 828 , proceed to 840 . [0211] If, at step 824 , nRecords is less than or equal to the openSlots, it is not necessary to make additional room in the AutoHits table and step 828 can be bypassed, proceeding instead to step 840 . [0212] By the time step 840 is executed, there is enough room in the table to insert the records. Since the table is ordered from least to most recent postings, but the list of records being inserted is ordered from most to least recent, the records are inserted in reverse order. Proceeding to step 844 , queries executed in this procedure are committed to the data store. After step 844 , return to the caller at step 848 . [0213] Those skilled in the art will recognize that the present invention has been described in terms of exemplary embodiments based upon use of a programmed processor (e.g., digital processing apparatus 1000 ). However, the invention should not be so limited, since the present invention could be implemented using hardware component equivalents such as special purpose hardware and/or dedicated processors that are equivalents to the invention as described and claimed. Similarly, general purpose computers, microprocessor based computers, micro-controllers, optical computers, analog computers, dedicated processors and/or dedicated hard wired logic may be used to construct alternative equivalent embodiments of the present invention. Moreover, although the present invention has been described in terms of a general purpose personal computer providing a playback mechanism, the playback can be carried on a dedicated machine without departing from the present invention. Conversely, the present decoder has been described in terms of a state machine and such state machine can be implemented as either a hardware or software based state machine. Moreover, those skilled in the art will understand that the exact register configurations, PID protocols and other details described in connection with the above exemplary embodiment should not be considered limiting, but are presented by way of illustration. [0214] Those skilled in the art will appreciate that the program steps and associated data used to implement the embodiments described above can be implemented using disc storage as well as other forms of storage such as for example Read Only Memory (ROM) devices, Random Access Memory (RAM) devices; optical storage elements, magnetic storage elements, magneto-optical storage elements, flash memory, core memory and/or other equivalent storage technologies without departing from the present invention. Such alternative storage devices should be considered equivalents. [0215] The present invention, as described in embodiments herein, is implemented using a programmed processor executing programming instructions that are broadly described above form that can be stored on any suitable electronic storage medium or transmitted over any suitable electronic communication medium or otherwise be present in any computer readable or propagation medium. However, those skilled in the art will appreciate that the processes described above can be implemented in any number of variations and in many suitable programming languages without departing from the present invention. For example, the order of certain operations carried out can often be varied, additional operations can be added or operations can be deleted without departing from the invention. Error trapping can be added and/or enhanced and variations can be made in user interface and information presentation without departing from the present invention. Such variations are contemplated and considered equivalent. [0216] Software code and/or data embodying certain aspects of the present invention may be present in any computer readable medium, transmission medium, storage medium or propagation medium including, but not limited to, electronic storage devices such as those described above, as well as carrier waves, electronic signals, data structures (e.g., trees, linked lists, tables, packets, frames, etc.) optical signals, propagated signals, broadcast signals, transmission media (e.g., circuit connection, cable, twisted pair, fiber optic cables, waveguides, antennas, etc.) and other media that stores, carries or passes the code and/or data. Such media may either store the software code and/or data or serve to transport the code and/or data from one location to another. [0217] While the invention has been described in conjunction with specific embodiments, it is evident that many alternatives, modifications, permutations and variations will become apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended that the present invention embrace all such alternatives, modifications and variations as falling within the scope of the appended claims. APPENDIX [0218] The Appendix, submitted on a computer readable medium, forms a part of the patent application entitled “Method and Apparatus to Search Data and Notify and Update a User.” [0219] This Appendix, which is hereby incorporated by reference herein in its entirety, includes computer programming code in the JAVA language. It should be recognized, however, that this code is not meant to limit the scope of the invention, but only to provide details for a specific embodiment. This Appendix includes the Appendix incorporated by reference above from U.S. Provisional Application No. 61/458,442, filed Nov. 23, 2010 entitled “Method and Apparatus to Search Data and Notify and Update a User,” which is hereby incorporated by reference herein in its entirety. REFERENCE TO COMPUTER PROGRAM LISTING APPENDICES [0220] Computer program listing appendix submitted electronically, corresponding to the program listings discussed below, is filed herewith, in accordance with 37 C.F.R. 1.52(e). This computer program listing appendix is incorporated herein by reference in its entirety, in accordance with 37 C.F.R. 1.77(b)(4). The aforementioned appendix was created on Nov. 14, 2013 and is a copy of a compact disc created on Nov. 22, 2010 submitted as an appendix to U.S. Provisional application No. 61/458,442 filed Nov. 23, 2010 by Larry Deutsch, which application and appendix are incorporated by reference in their entirety. [0221] The files submitted electronically are identified as follows: [0000] File Name Size Date Address.Java 3,439 Nov. 22, 2010 AppPreferenceActivity.java 5,219 Nov. 22, 2010 AutoHit.java 6,500 Nov. 22, 2010 BoundedLruCache.java 2,274 Nov. 22, 2010 Categories.java 9,255 Nov. 22, 2010 CheckBoxPreferenceWithLongSummary.java 1,557 Nov. 22, 2010 clear_data_dialog.xml 2,182 Nov. 22, 2010 ClearDataPreference.java 10,621 Nov. 22, 2010 colors.xml 651 Oct. 30, 2010 Constants.java 6,415 Nov. 22, 2010 Contact.java 3,147 Nov. 22, 2010 ContactAPI.java 2,095 Nov. 22, 2010 ContactAPI3.java 7,048 Nov. 22, 2010 ContactAPI5.java 8,878 Nov. 22, 2010 ContactList.java 1,218 Nov. 22, 2010 CraigslistHtmlParser.java 11,371 Nov. 22, 2010 CraigslistUrl.java 5,889 Nov. 22, 2010 custom_dialog.xml 2,267 Nov. 22, 2010 CustomAlertDialog.java 5,081 Nov. 22, 2010 Database.java 25,798 Nov. 22, 2010 Email.java 1,962 Nov. 22, 2010 FinditAlertService.java 8,645 Nov. 22, 2010 FinditApplication.java 6,479 Nov. 22, 2010 FinditServiceConnection.java 3,340 Nov. 22, 2010 FinditServiceReceiver.java 1,375 Nov. 22, 2010 HtmlParsingResults.java 1,573 Nov. 22, 2010 ImageDownloader.java 22,606 Nov. 22, 2010 ImageUrl.java 1,430 Nov. 22, 2010 Iso8601DateParser.java 2,433 Nov. 22, 2010 item_web_view.xml 1,029 Nov. 22, 2010 LineReader.java 3,818 Nov. 22, 2010 list_item_icon_text.xml 1,319 Nov. 22, 2010 list_item_text.xml 1,103 Nov. 22, 2010 location.xml 2,586 Nov. 22, 2010 LocationActivity.Java 25,128 Nov. 22, 2010 LocationRecord.Java 5,768 Nov. 22, 2010 Locations.java 22,742 Nov. 22, 2010 map_result_dialog.xml 3,176 Nov. 22, 2010 number_picker.xml 1,634 Oct. 17, 2010 NumberPicker.java 14,049 Nov. 22, 2010 NumberPickerButton.java 2,527 Sep. 19, 2010 Phone.java 1,888 Nov. 22, 2010 Range.Java 2,107 Nov. 22, 2010 RdfItem.Java 7,328 Nov. 22, 2010 RdfParser.java 26,178 Nov. 22, 2010 review_list.xml 1,285 Nov. 22, 2010 ReviewSearchResults.java 47,293 Nov. 22, 2010 save_result_dialog.xml 5,499 Nov. 22, 2010 save_search_dialog.xml 3,896 Nov. 22, 2010 saved_overview.xml 6,162 Nov. 22, 2010 SavedActivity.java 54,731 Nov. 22, 2010 search_criteria.xml 2,887 Nov. 22, 2010 SearchCriteria.java 26,016 Nov. 22, 2010 SearchItemAdapter.java 6,302 Nov. 22, 2010 SearchRequest.java 8,134 Nov. 22, 2010 SearchResult.java 5,908 Nov. 22, 2010 SearchTabActivity.Java 2,507 Nov. 22, 2010 sendto.xml 4,325 Nov. 22, 2010 ServiceCallable.java 1,164 Nov. 22, 2010 ServiceTimerTask.java 13,675 Nov. 22, 2010 spinner_view.xml 888 Nov. 22, 2010 spinner_view_dropdown.xml 891 Nov. 22, 2010 strings.xml 16,669 Nov. 22, 2010 StyleableSpannableStringBuilder.java 1,789 Nov. 22, 2010 styles.xml 1,517 Nov. 18, 2010 TimePickerPreference.java 11,691 Nov. 22, 2010 ToggleButtonGroupTableLayout.java 2,767 Nov. 22, 2010 UrlParam.Java 1,594 Nov. 22, 2010 Utils.java 26,315 Nov. 22, 2010 ViewItem.java 18,256 Nov. 22, 2010

The present invention allows a user to subscribe to multiple concurrent channels of syndicated content published over the internet. The user receives notification of the content which is new since the previous time that the user accessed a channel. The user can select the frequency of checking for new content and the user can specify how far back in time to check. In addition, the user can specify a maximum number of changes to be presented.

FIELD OF THE INVENTION [0001] The present invention relates to a trash storage device, and more particularly to a trash cart that stores daily trash and makes the transportation of the trash to the curb on pick-up day easier with a wheeled system. The trash cart is designed to protect the trash from animals, allow for ventilation, and to be decorative so as not to be an eyesore next the building in which it is stored. The trash cart can also be customized with decorative panels so as to match or complement the building next to which it is installed. BACKGROUND OF THE INVENTION [0002] Everyday life includes many chores that need to be done on a recurring basis. Home and business owner's daily storage and the task of taking out the garbage can be particularly challenging. In most areas, homeowners need to take the trashcans to the curb for pickup by the municipal or private garbage collectors at least once and most often several times a week. This can mean carrying, or rolling several individual trash cans to the front curb, which can be anywhere from ten feet away from the house to several hundred feet away from the house. [0003] For many homeowners this task is done early in the morning, rather than the night before pickup because animals, such as raccoons, fox, deer and the like often get into the trash cans and throw trash all over the lawn while looking for food. Currently, one of the only alternatives currently available to prevent waking up to a lawn full of trash is to take the trashcans to the curb the morning of pickup. Often, taking the trashcans to the curb the morning of pickup usually means it is done when the homeowner is dressed and rushing to work. [0004] Individual trashcans with wheels are easier to get to the curb than non-wheeled trashcans since they do not have to be carried. However, the wheeled trash cans do very little to protect the cans from being toppled and opened by animals if left outside overnight. Some trash cans use the handles from which they are pulled to lock the cover of the trashcan closed. Although a good concept, the handles are usually easily opened by determined rodents looking for their next meal and therefore are of little help. [0005] Another problem associated with using individual trash cans is the fact that the homeowner can transport only one wheeled trash can at a time to the curb. Therefore, it is often necessary for the homeowner to make several trips to complete the task. Making several trips can be time consuming and depending on the distance and incline from the house to the curb can be exhausting. This fact alone makes the option of using individual trashcans less attractive than the trash cart of the present invention. [0006] Between the assigned days for garbage pick up is the ongoing problem of daily garbage storage. Many people store garbage in their garage until pick up day. This often causes a space issue with cars and/or other items being stored as well as odors permeating the structure. Others opt to keep their garage outside using a multiple of solutions in order to ward off animals. This includes ropes and bungee cords attempting to secure the garbage and/or adding weighted objects to the top of the trash cans. Each time a homeowner adds trash, they must re-secure the trash can covers. [0007] There are devices available today that are used to transport trash cans to the curb for pick up but these devices are not enclosed, leaving the trash cans/garbage exposed to animals. Since the trash cans are not protected against animals, these devices must be stored inside and therefore are only marginally better than individual wheeled trash cans and do not solve the problem of garage space. [0008] Another problem faced by homeowners with trashcan transportation devices and trashcans available on the market today is that they are often unattractive. In stark contrast, the trash cart of the present invention has decorative panels that can be used to either match or complement the building next to which it is stored. [0009] Finally many of the transportation carts available on the market today are made of flimsy tube piping making the overall structure un-sturdy. [0010] Therefore in view of the foregoing shortcomings, what is needed is a trash cart that is sturdy enough to allow a homeowner to store their daily garbage, move the garbage to the curb easily and allow the homeowner to bring the cart to the curb the night before without worrying about the animals getting into the trash. Additionally, the cart is decorative so as to complement a building when stored on the side of the house or left at the curb for pickup. The present invention contains all of these attributes and more and solves the problems and shortcomings described above. SUMMARY OF THE INVENTION [0011] The present invention is directed to a trash cart comprising a front panel, a back panel, a right side panel, a left side panel, a top panel, and a bottom panel all of which are configured so that when they are attached they form an enclosure. The top panel of the trash cart may be configured to have at least one hinge means designed to attach one edge of the top panel of the trash cart to a second edge of the back panel. The result of this configuration is an enclosure having a hinged top panel that can be opened to expose the interior of the enclosure. [0012] The structure may also have a front panel having at least one hinge means that is configured so as to be in direct communication with at least one door, the door being contiguous with the front panel of the trash cart when closed and exposes an interior portion of the trash cart when opened. In an alternative embodiment of the trash cart, the trash cart is configured to have two doors on a hinge means that open in opposite directions to expose the interior of the trash cart. [0013] In still another embodiment the trash cart the trash cart is configured to have at least one wheeled axle located at the back portion of the bottom panel of the trash cart and at least one leg of the same height as the wheel is attached to the front portion of the bottom panel of the trash cart so that the trash cart is leveled. The wheeled axle makes transporting of trash cans in the trash cart easier for the user. In an alternative embodiment of the invention, a second wheeled axle is attached to the front bottom panel of the trash cart replacing the leg previously mentioned. The four-wheeled trash cart is designed to handle more weight than the single axel version. [0014] Both the single and multiple axel version of the present invention may be equipped with a steering mechanism that will allow the user to maneuver the trash cart to the curb on pick-up day and back to the storage place once the trash is collected. [0015] Another embodiment of the invention is directed to a trash cart kit. The trash cart kit comprises a front panel, a back panel, a left side panel, a right side panel, a top panel, and a bottom panel. Each panel having the proper holes, fasteners and bolts that can be used to assemble the individual panels together to form an enclosure. On the outside portion of the front panel, the back panel, the left side panel, the right side panel, and the top panel is an attaching means for attaching decorative panels. The kit can have several different decorative panels that can make the enclosure complement the building in which it belongs or an ornate structure such as plastic overlay design (such as basket weave) wrought iron design, stucco, wood frame, vinyl shingles, aluminum siding or the like to give it a unique look. [0016] The top panel can be hinged to the back panel so that it can open to reveal the trashcans stored inside. In one embodiment of the trash cart the top panel of the trash cart can be split in more than one portion, preferable two portions. Each of the aforementioned portions is configured so that they can be hinged to the back panel so as to open together or independently. The front panel can be designed so as to have a single or double doors hinged so that the door(s) can be opened to reveal the trash cans stored within the enclosure. [0017] As with the other embodiments described above, the trash cart kit may include one or two axles that can be attached to the bottom portion of the trash cart. Each axle may have at least one wheel, preferably two wheels, so as to support the trash cart and make it easy to move from one place to another. The kit may also contain illustrative instructions that describe how the described components fit together. BRIEF DESCRIPTION OF THE FIGURES [0018] FIG. 1 : ( 05 ) a full view of the trash cart with doors and top lids closed. ( 10 ) top panel ( 15 ) top hinges ( 20 ) top handle ( 25 ) right side panel ( 30 ) steering means ( 35 ) front axle ( 40 ) front wheel ( 45 ) rear axle ( 50 ) rear wheel ( 55 ) front door hinges ( 60 ) left front door ( 65 ) front lip ( 70 ) right front door ( 75 ) trash can ( 80 ) front door handle ( 85 ) structural front portion ( 90 ) separator panel [0037] FIG. 2 : ( 100 ) a full view of the trash cart with doors opened. ( 105 ) top hinges ( 110 ) top panel ( 115 ) separator panel ( 120 ) back panel ( 125 ) right side panel ( 130 ) steering means ( 135 ) right front door ( 140 ) front axle ( 145 ) front wheel ( 150 ) hooks for carrying bulky material ( 155 ) front lip ( 160 ) bottom panel ( 165 ) rear axle ( 170 ) rear wheel ( 175 ) left side panel ( 180 ) left front door ( 185 ) front support members ( 190 ) top handles [0057] FIG. 3 : ( 200 ) is a full view of the trash cart with doors open and on and top lid open. ( 205 ) open left top panel portion ( 210 ) left top handle ( 215 ) top panel hinges ( 220 ) closed right top panel portion ( 225 ) right side panel ( 230 ) steering means ( 235 ) open right front door ( 240 ) front axle ( 245 ) front wheel ( 250 ) back panel ( 255 ) separator ( 260 ) front lip ( 265 ) rear axle ( 270 ) wheel lock ( 275 ) rear wheel ( 280 ) left side panel ( 285 ) opened left front door ( 290 ) interior portion of trash cart ( 295 ) structural front member ( 300 ) interior space [0079] FIG. 4 : ( 400 ) a schematic of the kit assembly. ( 405 ) top panel ( 410 ) top panel hinges ( 415 ) separator panel ( 420 ) front panel handle ( 425 ) back panel ( 430 ) right side panel ( 435 ) left side panel ( 440 ) bottom panel ( 445 ) separator panel ( 450 ) wheel ( 455 ) axle ( 460 ) steering means ( 465 ) structural supports ( 470 ) left front door ( 475 ) right front door ( 480 ) steering connection ( 485 ) instructions ( 490 ) fasteners and bolts [0099] FIG. 5 : ( 500 ) is a top view of a panel with attaching hooks and decorative panels. ( 505 ) fastener for decorative panels ( 510 ) wrought iron decorative panel ( 515 ) decorative brick panel ( 520 ) decorative vinyl siding panel DETAILED DESCRIPTION OF THE INVENTION [0105] The present invention is directed to a decorative trash cart that is designed to provide outside storage of trashcans while preventing egress into the trashcans by animals. The trash cart of the present invention is also designed to be mobile so as to make moving the trashcans in the trash cart to the curb faster and easier than without a trash cart. These and other features are shown in FIGS. 1-5 of the present document and are further described below. [0106] One embodiment of the trash cart of the present invention shown in FIG. 1 comprises, a top panel ( 05 ), a bottom panel (shown in FIG. 2 ), a right side panel ( 25 ), a left side panel (shown in FIG. 2 ), a front panel and a back panel (shown in FIG. 2 ). The panels are arranged and fastened to each other so as to create an enclosure having a top, bottom, front, back and two walls. [0107] The top panel ( 10 ) of the trash cart ( 05 ) may be split into two portions by a separator panel ( 90 ) so that each of the two portions of the top panel ( 10 ) can be lifted independently by handles ( 20 ) revealing the top of the trash cans ( 75 ) within. The top panel ( 10 ) is connected to the back panel by multiple hinges ( 15 ) making it easy to lift the top panel portions so as to gain access to the trashcans ( 75 ). This feature can be used when trash is being placed into one of the trashcans ( 75 ) within the cart and there is no need to expose the other trashcans ( 75 ). Having the split top panel on hinges makes it easier for the user to gain access to the trashcans ( 75 ) within the cart. [0108] When the trashcans are filled and they need to be taken out, the top panel ( 10 ) can be opened and the trashcan lifted over the front panel out of the trash cart ( 05 ). This may be done when the trashcans are light, but if this is done when the trashcans are heavy it can cause a strain on the lifters back. It can also be messy if the trashcans are over filled. For this reason and others, the front panel of the trash cart can have at least one door that when closed is flush with the rest of the front panel. In one embodiment of the invention, the front panel comprises a left front door ( 60 ) and a right front door ( 70 ) that is contiguous with the structural front portion ( 85 ) of the trash cart. The left front door ( 60 ) and the right front door ( 70 ) are connected to the structural front portion ( 85 ) by front door hinges ( 55 ) and each door can be equipped with front door handles ( 80 ) so as to make it easy for the user to open the front doors. The front doors may be locked using a latch or a keyed system. [0109] The front panel may also have a front lip ( 65 ) that is in communication with the lower portion of the front panel. The front lip is designed to stop the trashcans ( 75 ) from falling out of the trash cart once the front doors are opened after the cart has been moved. Since the trashcans ( 75 ) may shift during movement of the trash cart, the front lip ( 65 ) is designed to prevent the trashcans ( 75 ) from accidentally falling out when opened. [0110] In another embodiment of the invention, the trash cart ( 05 ) can be equipped with either just a rear axel ( 45 ) having at least one rear wheel ( 50 ) or a front axle ( 35 ) and a rear axle ( 45 ). The front axle ( 35 ) having at least one wheel ( 40 ) and the rear axle ( 45 ) having at least one wheel ( 50 ). In a preferred embodiment of the invention, the front axle ( 35 ) and the rear axle ( 45 ) each have two wheels. One of the two wheels is attached to each end of the axles so as to distribute the load in the trash cart. The rear axle ( 50 ) can be attached to the bottom portion of the bottom panel of the trash cart so as to be stationary. The front axle ( 40 ) on the other hand can be pivotally attached so as to provide the trash cart with some maneuverability. [0111] In addition, the front axle ( 35 ) can be attached to a steering means ( 30 ) that when maneuvered can cause the front axle to turn in the direction that the user wants the trash cart ( 05 ) to move towards. The steering means ( 30 ) can also be used to pull the trash cart to the intended site whether it is to the curb for trash pick-up or back to the storage spot on the side of the building. [0112] As mentioned above, the trash cart ( 05 ) can be equipped with a separator ( 90 ) and a front lip ( 65 ). These structures are designed to aid in keeping the trashcans ( 75 ) in place while the trash cart ( 05 ) is moved from one place to another. The trash cart ( 05 ) can also be equipped with locking trim that can be attached to the interior portion of the bottom panel of the enclosure that will prevent the trashcans ( 75 ) from moving during movement of the trash cart ( 05 ). [0113] The overall construction of the panels can be made out of wood, wrought iron, aluminum, stainless steel, powder coated aluminum, plastic, polyvinyl chloride, powder coated steel, plastic coated metal, man-made materials, new-age materials, or any other material that is washable, and strong and durable enough for the intended use of the trash cart. The trash cart should be designed so as to have enough holes in the structure so as to allow amble ventilation so as to prevent spontaneous combustion of the trash. The holes are also needed to allow rain water and water used to clean the trash cart to run out of the structure so as to prevent pooling of excess water. [0114] FIG. 2 shows the trash cart of the present invention with the front doors in the open position. The trash cart ( 100 ) comprises a top panel ( 110 ), a bottom panel ( 160 ), a right side panel ( 125 ), a left side panel ( 175 ), and a back panel ( 120 ). As in FIG. 1 , the above panels are arranged and fastened to each other so as to create an enclosure having a top, bottom, front, back and two walls. A separator ( 115 ) divides the interior space into two separate portions so as to keep the two trashcans separate. Although FIGS. 1 and 2 are shown having two doors, two top panels, one separator creating two compartments, it is well within the scope of the invention to have additional doors and compartments. [0115] The right front door ( 135 ) and left front door ( 180 ) can be opened so as to be flat against the structural front portion ( 185 ) of the front panel. Using special hinges, the front doors can be made to wrap around the structural front portion ( 185 ) of the front panel so as to remain flat against the left side panel ( 175 ) and the right side panel ( 125 ) when in the opened position. Once in this position, the doors can be latched back so as to not swing close unexpectedly. This feature is extremely helpful when the user is power washing the interior of the trash cart or when the trashcans are being removed from the trash cart and the cart is on unleveled ground. [0116] As in FIG. 1 , the top panel ( 110 ) of the trash cart ( 100 ) may be split into two portions by a separator panel ( 115 ) so that each of the two portions of the top panel ( 110 ) can be lifted independently by handles ( 190 ) revealing the interior portion of the trash cart ( 100 ). The top panel ( 110 ) is connected to the back panel by multiple hinges ( 105 ). [0117] As shown in FIG. 2 , the trash cart ( 100 ) is equipped with a rear axel ( 165 ) having wheels ( 170 ) attached to each end of the rear axle ( 165 ) and a front axle ( 140 ) having wheels ( 145 ) attached to each end of the front axle ( 140 ). The rear axle ( 165 ) is fixed to the bottom portion of the bottom panel ( 160 ) and the front axle ( 140 ) is pivotally attached to a different portion of bottom panel so that the axle can shift from side to side so as to steer the trash cart. [0118] The front axle ( 140 ) is attached to steering means ( 130 ) that when maneuvered causes the front axle and it's attached wheels to turn in the direction that the user wants the trash cart ( 100 ) to move towards. As stated above in FIG. 1 , the steering means ( 130 ) can also be used to pull the trash cart to the intended site. The wheels of the front and/or back wheels can be equipped with a locking mechanism to prevent the trash cart from rolling if left on un even ground. The trash cart can also be equipped with a hook system ( 150 ) (not shown) that can be attached to the side and or back of the trash cart that can be used to carry bulky items such as an old latter, old doors, and the like to the curb on pick-up day. [0119] FIG. 3 shows another view of the present invention wherein the front doors are in the open position and one of the top panel portions is in the lifted position. All of the components of the trash cart of FIG. 2 are also in the embodiment shown in FIG. 3 . The embodiment shown in FIG. 3 shows a locking mechanism ( 270 ) on the rear axle that is designed to lock the wheels in placed so as to prevent the trash cart from rolling if left on un-even ground. This same mechanism can be attached to the front axle instead of the rear axle or on both the front and rear axle of the trash cart. It is within the scope of the invention to use the locking wheel mechanism in all of the embodiments described herein. [0120] Still another embodiment of the invention is directed to a trash cart kit comprising a top panel ( 405 ), top panel hinges ( 410 ), separator panel ( 415 ), front panel handle ( 420 ), back panel ( 425 ), right side panel ( 430 ), left side panel ( 435 ), bottom panel ( 440 ), separator panel ( 445 ), wheels ( 450 ), axles ( 455 ), steering means ( 460 ), structural supports ( 465 ), left front door panel ( 470 ) right front door panel ( 485 ), steering connection ( 480 ), instructions to assemble the trash cart ( 485 ), and various fasteners, bolts and pins necessary to connect all of the parts together. The trash cart kit is shown in FIG. 4 and is designed to be easily assembled. The trash cart kit is easier to ship, store, and package, all of which results in savings that can be passed on to the consumer. In addition, compact packaging also allows the consumer to transport the trash cart from the store to home without a truck. [0121] The trash cart, once assembled, has all of the features, attributes and benefits of the fully assembled versions shown in FIGS. 1-3 . The trash cart kit can also includes special fasteners that allow the owner to decorate the trash cart so as to be pleasing to the eye, match the structure in which is stored next to or to just to personalize the cart. For example, the kit can include special fasteners and a printable plate that can be engraved and/or printed with the name and/or address of the owner. [0122] In still another embodiment of the invention, the panels can be almost completely solid having only a few holes for water drainage and/or ventilation. The fasteners can be attached to the top panels ( 405 ), back panel ( 425 ), right side panel ( 430 ), left side panel ( 435 ), bottom panel, left front door panel ( 470 ) and right front door panel allowing for decorative panels to be attached. The decorative panels can be made out of material selected from the group consisting essentially of wood, wrought iron, aluminum, stainless steel, powder coated aluminum, plastic, polyvinyl chloride, powder coated steel, plastic coated metal, man-made materials, new-age materials, or any other material that is washable, strong enough and durable enough for trash cart wear. Custom panels can be made so as to match any structure or to make any trash cart unique. [0123] Another feature that can be added to the trash cart is an internal light that turns on automatically using a light sensor when either the top panel or front doors are opened. This light can be powered by solar or energy from a battery. The same solar charge/battery pack can be used to power an odor control unit that emits a scent to mask the smell of the trash either on a timer or using a malodorous detector that activates the fragrance emitter when odors reach a certain detectable level. All of these features are known in the art but are unique when incorporated into the present invention. [0124] FIG. 5 gives several examples of decorative panels. These are only examples and many other designs can be used and are anticipated to fall with the scope of the invention. These panels should be weather resistant; however, making the trash cart from a virtually indestructible material will allow the cart to last while changing the decorative panels on the outside would allow the trash cart to look new even though the internal structure is old. This is a direct savings to the consumer and opens up an additional market for decorative panels. [0125] The above embodiments of the present invention can be manufactured using well-established manufacturing techniques used in similar industries today. The technique used to make the present invention is directly related to the material used to make the trash cart. For example, if plastic is used to make the trash cart then the well-established technique of cast molding maybe used. If metals are used to make the trash cart, then welding and/or drop forging of metals maybe used to make the trash cart. And finally, if wood is used to make the present invention then standard wood milling and carpentry techniques can be used. The aforementioned list is not meant to be an exhaustive list designed to cover all of the possible techniques that can be used to make the invention but are only offered as examples. One skilled in the art would manufacture the trash cart using techniques available at the time the trash cart is manufactured. [0126] The materials used to make the present invention should be durable enough to withstand the abuse often associated with trash cans but must be light enough so that the trash cart can be moved easily and without undue effort just to carry the weight of the trash cart. [0127] In another embodiment of the invention, the trash cart is equipped with a motor that is in direct communication with at least one wheel and/or axle of the trash cart that when powered would rotate the wheel and/or axle so as to move the trash cart in the forward or reverse direction. The motor can be powered by gas, electric or some combination of each and can be controlled by either a remote control device or a direct control device. [0128] So as not to allow egress of small animals into the main compartment of the trash cart, the panels should have predominately solid construction having only strategic holes for ventilation and water drainage. The enclosure should also be designed to keep most of the rainwater from getting into the structure. To achieve this task the structure is designed to have a slanted roof so as allow rain to run off of the top panel and avoid pooling of excess water. Although the main compartment of the trash cart is predominately solid construction the homeowner is able to achieve a more airy look using the decorative overlay panels. In other words, the overlay panels, once attached, would allow the home owner to achieve the wrought iron look that by definition has large spaces between each segment—spaces too large to be able to keep animals from getting into the trash cart—while still protecting the trash from animals. [0129] As with most things in life, the trash cart of the present invention would be able to marketed as a standard model containing the basic structure to the deluxe model comprising the basic model plus the add-on features such as decorative overlay panels, outside lighting, odor diffuser, motor with remote control as well as other added features that complement the basic features of the invention. The trash cart can be designed to fit one or more trash cans, preferably two trash cans. [0130] In summary, the present invention is directed to a trash cart that is mobile, easy to get trash cans in and out of, protects the trash cans from animal destruction, is durable, decorative and allows the user to store and transport the trash cans to the curb for collection quickly and without getting soiled. [0131] While the invention has been illustrated and described with respect to specific illustrative embodiments and modes of practice, it will be apparent to those skilled in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. Accordingly, the invention is not to be limited by the illustrative embodiment and modes of practice.

The present invention is directed to a trash cart, namely an enclosed trash cart having a top and front doors that swing open on a hinged system. The enclosed trash cart is connected to at least one wheel axle having wheels that allow the cart to be transported from a storage area to the curb for garbage pickup. The trash cart can also have an attachment system that gives the owner the option of overlaying a number of different external decorative panels to the trash cart making the cart both functional and decorative. The trash cart of the present invention enables a homeowner to store daily garbage outside the home or garage in a decorative enclosure that keeps the garbage protected from animals and makes it easy to transport garbage to the curb on pick-up day.

TECHNICAL FIELD [0001] The present invention relates to flow measuring apparatuses to measure the flow of fluid, and particularly relates to airflow measuring apparatuses that are suitable for intake airflow of an internal combustion engine for automobile. BACKGROUND ART [0002] Conventionally heat-generation type airflow sensors are becoming the mainstream to measure the intake airflow, which are installed in an intake air passage of an internal combustion engine in automobile or the like, because such a type of sensor can detect mass airflow. [0003] A sensor element can be formed as a thinner film partially by a semiconductor micromachining technique, whereby the airflow sensor can have high-speed responsivity. Hereinafter this thin-film part is called a diaphragm. On the diaphragm, a heating resistor and two or more thermosensitive resistors adjacent to the heating resistor are formed by patterning. The heating resistor is uniformly controlled to generate heat to be at a predetermined temperature or higher than the surrounding temperature, and the temperature distribution thereof is detected by the thermosensitive resistors. Since the temperature distribution changes with the amount of airflow passing over the sensor element, the variation in temperature distribution is detected by the thermosensitive resistors disposed upstream and downstream of the airflow direction, whereby the mass airflow can be measured. [0004] As means for such a heat-generation type airflow meter using a sensor element, the sensor element and a lead frame to mount the sensor element thereon are surrounded with resin as a package by transfer molding, for example. [0005] This is for reducing the number of components or the number of connections compared with the structure including a sensor element and a circuit mounted on a substrate made of ceramic or the like. [0006] Such a sensor element and the thermal flow meter including such a packaged sensor element have the following problems. [0007] To begin with, when stress is applied to the heating resistor and the thermosensitive resistors disposed on the diaphragm, their values of resistance change due to Piezoresistive effect, which becomes an erroneous cause of the mass airflow detected. If a pressure difference occurs between the surface and the rear face of the diaphragm part, the diaphragm part is deformed, so that stress is applied to the heating resistor and the thermosensitive resistors. To avoid this, there is a need to suppress such a pressure difference between the surface and the rear face of the diaphragm part. [0008] As a method to reduce the pressure difference between the surface and the rear face of the diaphragm, Patent Literature 1 provides an opening at the surface of a diaphragm or at the rear face of a substrate to mount a sensor element thereon for communication between a cavity at the rear face of the diaphragm and the atmospheric pressure at the surface of the diaphragm. CITATION LIST Patent Literature [0000] Patent Literature 1: JP 2008-20193 A SUMMARY OF INVENTION Technical Problem [0010] The method described in Patent Literature 1, however, cannot avoid contaminants or droplet completely from entering through the opening at the surface of the diaphragm or on the side of the rear face of the substrate to support the diaphragm, because the opening is exposed to the interior of the intake pipe. [0011] When the sensor element is mounted on a lead frame, followed by packaging by transfer molding, the cavity part at the rear face of the diaphragm will be completely cut off from the air. This means that, if the surrounding temperature of the chip package changes, the volume of the air in the cavity at the rear face of the diaphragm changes, and so a difference in pressure between the atmospheric pressure applied to the surface of the diaphragm and the air pressure at the rear face of the diaphragm deforms the diaphragm. This deformation changes the values of resistance of the heating resistor and the thermosensitive resistors on the diaphragm change due to Piezoresistive effect, thus generating an error in the mass airflow detected. [0012] In this way, there is a need to establish a communication between the space at the rear face of the diaphragm part and the atmosphere to remove a difference in air pressure between the surface and the rear face of the diaphragm due to the influences from temperature. [0013] On the diaphragm, a heating resistor is disposed to detect the flow, and water droplet or contaminations in the intake pipe will fly to the diaphragm part as stated above. Although an opening has to be bored to remove the difference in air pressure so as to lead the space at the rear face of the diaphragm part to any part of the thermal airflow meter, if such an opening is bored at the position that is exposed to the interior of the intake pipe, contaminations or water droplet reaching the opening may block the opening. [0014] There is another problem of displacement of the mounting position of the sensor element. As stated above, the temperature distribution generated by a heater is based on the detection of the flow rate of air passing over its surface. Since the flow-rate distribution in a bypass-passage to mount a sensor element is not uniform, the displacement of the sensor element mounted causes a change in the flow detected by such a sensor element, meaning that the mass airflow cannot be measured correctly. To prevent this, there is a need to mount a sensor element precisely in the package. [0015] It is an object of the present invention to provide an airflow measuring apparatus with good measurement accuracy. Solution to Problem [0016] To fulfill the above object, an airflow measuring apparatus of the present invention includes: a sub-passage that takes in a part of a flow of fluid flowing through an intake pipe; a sensor element that is disposed in the sub-passage to measure the flow of fluid; a circuit part that converts the flow of fluid detected by the sensor element into an electric signal; a connector part having a connector that is electrically connected to the circuit part to output a signal externally; and a casing that supports the sensor element and the circuit part, the sensor element being disposed in the intake pipe. The sensor element includes a cavity that is disposed at a semiconductor substrate, and a diaphragm including a thin film part that covers the cavity. The sensor element is mounted at a lead frame. The sensor element and the lead frame have surfaces that are mold-packaged with resin so that a diaphragm part of the sensor element and a part of the lead frame are exposed. At least one hole is disposed at the lead frame for communication between the cavity and exterior of the mold package. Advantageous Effects of Invention [0017] The present invention can provide an airflow measuring apparatus with good measurement accuracy. BRIEF DESCRIPTION OF DRAWINGS [0018] FIG. 1 illustrates the state to mount a thermal airflow meter to an intake pipe. [0019] FIG. 2 illustrates the structure of a thermal airflow meter and its components. [0020] FIG. 3 illustrates a detection part of a sensor element. [0021] FIG. 4 includes a plan view and a cross sectional view of a chip package that is Embodiment 1. [0022] FIG. 5 includes a plan view and a cross sectional view (1) illustrating the shapes of a cover frame, adhesive and a lead frame that are components of a lead frame assembly that is Embodiment 1. [0023] FIG. 6 includes a plan view and a cross sectional view illustrating a step of Embodiment 1 in the state where a cover frame is mounted. [0024] FIG. 7 includes a plan view and a cross sectional view illustrating a step of Embodiment 1 in the state where a sensor element is mounted at a lead frame assembly. [0025] FIG. 8 includes a plan view and a cross sectional view illustrating a step of Embodiment 1 after transfer molding. [0026] FIG. 9 includes a plan view and a cross sectional view (1) illustrating the shapes of a cover frame, adhesive and a lead frame that are components of a lead frame assembly that is Embodiment 2, which is one alternative proposal for Embodiment 1. [0027] FIG. 10 includes a plan view and a cross sectional view (2) illustrating the shapes of a cover frame, adhesive and a lead frame that are components of a lead frame assembly that is Embodiment 3, which is another alternative proposal for Embodiment 1. [0028] FIG. 11 illustrates Embodiment 4, illustrating a cutting part of an outer lead including a communication hole. [0029] FIG. 12 is an enlarged view of a cut end of an outer lead cutting part including a communication hole. [0030] FIG. 13 illustrates an alternative proposal to mount a plurality of chips and an alternative proposal to improve the connection reliability at a cutting part. [0031] FIG. 14 includes a plan view and a cross sectional view illustrating the shapes of a cover frame, adhesive and a lead frame that are components of a lead frame assembly that is Embodiment 8. [0032] FIG. 15 includes a plan view and a cross sectional view illustrating a step of Embodiment 8 in the state where a cover frame is mounted. [0033] FIG. 16 includes a plan view and a cross sectional view illustrating a step of Embodiment 8 in the state where a sensor element is mounted at a lead frame assembly. [0034] FIG. 17 includes a plan view and a cross sectional view (1) illustrating the shapes of a cover frame, adhesive and a lead frame that are components of a lead frame assembly that is Embodiment 9, which is one alternative proposal for Embodiment 1. [0035] FIG. 18 includes a plan view and a cross sectional view (2) illustrating the shapes of a cover frame, adhesive and a lead frame that are components of a lead frame assembly that is Embodiment 10, which is another alternative proposal for Embodiment 1. [0036] FIG. 19 illustrates an alternative proposal to form a communication groove by pressing by bending a lead frame that is Embodiment 11. [0037] FIG. 20 illustrates the alternative proposal to form a communication groove by pressing by bending a lead frame that is Embodiment 11. [0038] FIG. 21 illustrates another alternative proposal to form a communication groove by etching by bending a lead frame that is Embodiment 11. [0039] FIG. 22 illustrates the alternative proposal to form a communication groove by etching by bending a lead frame that is Embodiment 11. [0040] FIG. 23 includes a plan view and a cross sectional view illustrating the shapes of a cover frame, adhesive and a lead frame that are components of a lead frame assembly that is Embodiment 12. [0041] FIG. 24 includes a plan view and a cross sectional view illustrating a step of Embodiment 12 in the state where a cover frame is mounted. [0042] FIG. 25 includes a plan view and a cross sectional view illustrating a step of Embodiment 12 in the state where a sensor element is mounted at a lead frame assembly. [0043] FIG. 26 illustrates a step of Embodiment 12, including a plan view after transfer molding and a cross sectional view illustrating the state where a lead frame is pressed with a mold during transfer molding. [0044] FIG. 27 illustrates a method that is Embodiment 13 to form a communication hole at a lead frame by additional processing. [0045] FIG. 28 illustrates a method that is Embodiment 14 to form a communication hole using a pipe-formed member. [0046] FIG. 29 illustrates a die-bond material receiver at the periphery of a through hole that is Embodiment 15. DESCRIPTION OF EMBODIMENTS [0047] The following describes embodiments of the present invention in details, with reference to the drawings. Embodiment 1 [0048] The following describes Embodiment 1 that is one embodiment of the present invention. [0049] As illustrated in FIG. 1 , a thermal flow meter 100 is attached at its flange part 99 to an intake pipe 140 by mechanical fastening such as using a screw. The thermal flow meter 100 roughly includes a bypass-passage 101 , a circuit chamber 102 and a connector part 103 , and is electrically connected to an ECU that controls an engine via a connector lead 111 in the connector part 103 . Intake air 110 flowing through the intake pipe 140 enters the bypass-passage through an upstream-side opening 105 of the thermal flow meter 100 and goes out through a downstream-side opening 106 . A sensor element 701 is disposed in the bypass-passage 101 to detect the flow of air that is branched off into the bypass-passage 101 out of the intake air 110 passing through the intake pipe 140 . [0050] Referring to FIG. 2 that is a cross section taken along A-A of FIG. 1 , the following describes components making up the thermal flow meter 100 and the structure. [0051] The circuit chamber 102 and the bypass-passage 101 of the thermal flow meter 100 are surrounded with a housing member 201 , a cover member 202 , and a chip package 203 containing the sensor element 701 and its driving circuit. These members are mutually bonded at their periphery with thermosetting adhesive 104 . This can keep the interior of the circuit chamber 102 airtight perfectly, and intake air 110 passing through the sub-passage 101 does not enter the circuit chamber 102 . Such perfect airtightness of the circuit chamber, however, causes expansion of air in the circuit chamber during heating of the thermosetting adhesive 104 for curing, and so the housing member 201 and the cover member 202 may not be bonded correctly. [0052] To avoid this, such expanded air has to be released from the circuit chamber 102 , and so a ventilation hole 108 is bored at the connector part 103 to communicate with the circuit chamber 102 for communication between the air inside the circuit chamber 102 and the atmosphere 109 outside the intake Pipe. [0053] An outer lead 305 of the chip package 203 and the connector lead 111 inside the connector part 103 are electrically connected via aluminum wire 112 , for example. Herein as illustrated in FIG. 2( b ), the outer lead 305 of the chip package may double as the connector lead 111 , and in this case, the aluminum wire 112 and the circuit chamber 102 may be omitted. [0054] FIG. 3( a ) illustrates the minimum circuit configuration of a flow detection part, FIG. 3( b ) illustrates the configuration of the flow detection part and FIG. 3( c ) is a cross-sectional view taken along A-A of FIG. 3( b ). Referring to these drawings, the following describes a typical example of the flow detection part that is formed by patterning on a detection part diaphragm 702 and its operation principle. [0055] On the diaphragm 702 , a flow detection part 4 is formed by patterning. The flow detection part 4 includes a heater resistor (heating resistor) 7 and a non-thermal resistor (thermosensitive resistor) 9 , and they are connected to a driving circuit 5 that is provided separately from the flow detection part 4 . The heater resistor 7 generates heat when being energized by current fed from the driving circuit 5 described later, so as to heat the surrounding fluid (air) to be at a temperature higher than the surrounding temperature at least. The non-thermal resistor 9 detects a temperature of the fluid surrounding the flow detection part, and the heater resistor 7 is heat-controlled by the driving circuit 5 so that the temperature thereof is higher than the detected temperature by a predetermined temperature or more. [0056] The flow detection part 4 further includes temperature sensors (temperature detection resistors) 11 , 12 disposed adjacent to the downstream of the heater resistor 7 and temperature sensors (temperature detection resistors) 13 , 14 disposed adjacent to the upstream of the heater resistor 7 , which are connected to a constant voltage source 26 that is separately provided from the flow detection part 4 and make up a bridge circuit 45 . [0057] The driving circuit 5 includes fixed resistors 8 , 10 and an operational amplifier 15 disposed therein, and so is configured as a heater control circuit to heat-control the heater resistor 7 . This driving circuit 5 allows current from the operational amplifier 15 to be fed to the heater resistor 7 so as to heat-control the heater resistor 7 based on the detection temperature of the non-thermal resistor 9 until the heating temperature of the heater resistor 7 has a predetermined value relative to the surrounding temperature (fluid). [0058] In this way, a change in temperature distribution (heat quantity) of the fluid between the temperature sensors 13 and 14 disposed adjacent to the upstream of the heater resistor 7 and the temperature sensors 11 and 12 disposed adjacent to the downstream of the heater resistor 7 can be detected as the flow of the fluid (detected flow Q). When the mass airflow changes, thermal influences from the heater resistors on the temperature sensors 13 and 14 disposed adjacent to the upstream and the temperature sensors 11 and 12 disposed adjacent to the downstream of the heater resistor 7 change, and such a change is detected, whereby a voltage signal corresponding to the mass airflow and its direction can be obtained. [0059] As illustrated in FIG. 3( b ), the heater resistor 7 has a folded pattern of a resistor to be oblong, on both sides of which (upstream and downstream sides) the temperature sensors 11 and 12 and the temperature sensors 13 and 14 are disposed. The heater resistor 7 and the temperature sensors 11 , 12 , 13 and 14 are disposed on the diaphragm 702 that is formed by etching from the rear face of the sensor element 701 as a silicon substrate, for example, to have a small thermal capacity. The non-thermal resistor 9 may be disposed at a place less susceptible to temperature influences from heating of the heater resistor 7 , e.g., at a place outside of the diaphragm 702 . These elements are connected for electrical connection with a circuit part by gold wire bonding, for example, from an electrode extraction part 42 . In the present embodiment, the potential at the midpoint of the bridge including the temperature sensors 11 , 12 , 13 and 14 is input to a characteristic adjusting circuit 6 . [0060] Referring next to FIG. 4( a ) that is a front view of a package illustrating the internal configuration with broken lines and FIG. 4( b ) that is a cross-sectional view of FIG. 4( a ), the following describes the shape of the chip package 203 . [0061] The sensor element 701 typically has a rectangular shape. At the detection part of the sensor element 701 , the diaphragm 702 is disposed as described above, and this diaphragm 702 is disposed inside the sub-passage 101 illustrated in FIG. 1 , through which air as a measurement target flows. [0062] The diaphragm 702 is formed by etching from the rear-face direction of the sensor element 701 as stated above, and a cavity 703 is formed at the rear face. The diaphragm 702 is made to be a thin film mainly because a thinner film can decrease the thermal capacity, leading to advantages of improving thermal responsivity as well as lowering power consumption. [0063] The cavity 703 below the diaphragm 702 and the circuit chamber 102 communicate with each other via a communication hole 705 bored at a lead frame 704 . The lead frame 704 may be made of a material such as Cu or Fe—Ni having a thickness from about 0.1 mm to 1 mm. When the diaphragm 702 and the circuit chamber 102 communicate with each other, the communication hole 705 has to be bored at the lead frame 704 or a resin part 601 of the chip package 203 . Boring of a hole at the resin part 601 or at the lead frame 704 by additional process after packaging means an increase in the number of steps compared with the conventional packaging procedure, and such a step includes micromachining, and so requires high level of difficulty for machining. [0064] Then, the present invention provides the communication hole 705 inside the lead frame 704 by the following procedure for communication between the circuit chamber 102 and the cavity 703 under the diaphragm. In the following, an assembly (including a lead frame 301 , a cover frame 401 and adhesive 404 in the present embodiment) of the minimum components of the lead frame 704 to configure the communication hole 705 is called a lead frame assembly 704 . [0065] Referring to FIGS. 5 to 8 , the following describes the manufacturing procedure of the chip package 203 . [0066] Firstly, the cover frame 401 and the lead frame 301 are prepared. Hereinafter, the aforementioned first lead frame and second lead frame are called the cover frame 401 and the lead frame 301 , respectively. Referring to FIGS. 5( a )( b ) and ( c ), the following describes the shapes of the cover frame 401 , the lead frame 301 and the adhesive 404 to bond the cover frame 401 and the lead frame 301 . [0067] Firstly, the configuration of the lead frame 301 is described with reference to FIG. 5( c ). The lead frame 301 includes an outer frame 302 , a die pad 303 to mount an electronic component such as a sensor element and the cover frame 401 thereon, a tie bar 304 to joint the outer frame 302 to the die pad so as not to cause displacement of these components due to influences from resin flow that may occur during molding by transfer molding described later, and an outer lead 305 of the chip package. [0068] Next, the configuration of the cover frame 401 is described with reference to FIG. 5( a ). [0069] The cover frame 401 includes a groove 402 (hereinafter called a communication groove 402 ) to release air from the cavity 703 below the diaphragm, which is formed by half etching or pressing, and a through hole 403 passing through the groove part, which is bored at a part immediately below the diaphragm in the area where the sensor element is to be die-bonded. Such a cover frame 401 is overlaid to the lead frame 301 with the sheet adhesive 404 illustrated in FIG. 5( b ). [0070] FIG. 6( a ) is a front view illustrating the state where the lead frame 301 and the cover frame 401 are bonded with the adhesive 404 , and FIG. 6( b ) is a cross sectional view thereof. Bonding of the lead frame 301 and the cover frame 401 via the adhesive 404 forms a closed space that communicates with the through hole 403 . Hereinafter this closed space defines the communication hole 705 . [0071] FIG. 7( a ) is a front view illustrating the state where the sensor element 701 is structurally or electrically bonded to the lead frame assembly 704 , and FIG. 7( b ) is a cross sectional view thereof. [0072] After applying a die-bond material 501 made of Ag paste or thermosetting adhesive so as to surround the through hole on the cover frame 401 , the sensor element 701 is die-bonded, and the die-bond material 501 and the adhesive 404 are heated in an oven for curing. Herein, the lead frame 301 and the cover frame 401 may be made of the same type of materials or different types of materials, between which one that is suitable for the overall shape of the chip package 203 may be selected. For instance, when the area of the lead frame 301 is sufficiently larger than that of the cover frame 401 , the cover frame 401 may be made of a material having a linear expansion coefficient closer to that of the sensor element 701 than that of the lead frame 301 , whereby stress applied to the sensor element 701 during heating for curing can be alleviated. [0073] Then, the electrode extraction part 42 on the sensor element 701 and a bonding part 503 on the lead frame 301 are connected by wire bonding using Au wire 504 . [0074] FIG. 8( a ) is a front view illustrating the state where molding is performed for the lead frame assembly 704 on which the sensor element 701 has been mounted, and FIG. 8( b ) is a cross sectional view illustrating the state where the lead frame assembly is set in a mold. [0075] The lead frame assembly 704 on which the sensor element 701 has been mounted, which is prepared by the procedure till FIG. 7 as stated above, is set on a lower mold for transfer molding 1103 , which is then sandwiched with an upper mold for transfer molding 1102 . Thermosetting resin such as epoxy or polyamide that is heated to about 200° C. to 300° C. is injected into the space defined between the lower mold for transfer molding 1103 and the upper mold for transfer molding 1102 at an injection pressure of about 5 to 10 MPa, thus packaging the lead frame assembly 704 . Hereinafter the shape of such a lead frame assembly 704 , on which an electronic component such as the sensor element 701 has been mounted, just after packaging, is called a package assembly 602 . [0076] At this time, if the injection pressure of the resin part 601 is too high, the Au wire 504 will be washed away by the resin part 601 and will fall, and the Au wire 504 may come into contact with the cover frame 401 . When the cover frame 401 is made of a metal material, short-circuit occurs at the Au wire 504 , and the sensor element 701 and the outer lead 305 may not be electrically connected correctly. [0077] To avoid this, the cover frame 401 may be made of a material not a metal only but silicon or glass. In the case of silicon or glass used, the communication groove 402 and the through hole 403 may be formed by wet etching, dry etching or blasting. Such a configuration including silicon or glass may be applicable to all cover frames 401 in the below-described embodiments. [0078] Cutting the tie bar 304 of the package assembly 602 , a part connecting the outer leads 305 of the tie bar 304 and the leading end of the outer lead 305 completes the chip package 203 of FIG. 4 as described above. At this time, the outer lead 305 particularly has to be cut at its cutting line 1101 . The outer lead may be cut at the cutting line 1101 so as to surely include the communication groove 402 , whereby the opening 708 of the communication hole can be obtained as in FIG. 4( b ) as described above. [0079] As stated above, the chip package 203 , the housing member 201 and the cover member 202 define the sub-passage 101 and the circuit chamber 102 , and so air inside the cavity 703 below the diaphragm flows through the communication hole 705 , the circuit chamber 102 and the ventilation hole 108 to communicate with the atmosphere 109 outside of the intake pipe through the connector part 103 . [0080] Packaging of the sensor element 701 by such manufacturing procedure and to have such a configuration allows the space below the diaphragm to be cut off from the interior of the intake pipe 140 , and so concern about water droplet and contaminations to reach there can be removed. Further, the cavity 703 below the diaphragm and the circuit chamber 102 can communicate with each other without adding any step to a typical packaging technique conventionally conducted. Since the cavity 703 below the diaphragm communicates with the atmosphere, deformation of the diaphragm 702 can be reduced, which is due to a pressure difference between the surface side and the rear face side of the diaphragm, and so a change in values of resistance of resistors making up the flow detection part 4 on the diaphragm 702 due to Piezoresistive effect can be reduced, and a change in characteristics of the thermal flow meter 100 can be reduced. Clogging of the opening leading to the space at the rear face of the diaphragm also can be prevented, and so a reliable product can be manufactured. [0081] A ventilation hole that is provided at the sensor element for communication between the space at the rear face of the diaphragm and the exterior of the intake pipe will not be clogged, and the sensor element can be manufactured while suppressing variations in mounting. [0082] Although the present embodiment illustrates the example providing a communication hole in the lead frame, including the below-described embodiments, the present invention is intended to provide a communication hole in a member to support the sensor element. That is, the present invention is not limited to these embodiments, and a communication hole may be provided at a substrate making up a circuit pattern, for example. Embodiment 2 [0083] Referring to FIG. 9 , the following describes a cover frame 401 , a lead frame 301 and the shape to apply adhesive 404 that is another proposal for Embodiment 1. [0084] Embodiment 1 requires half etching or pressing to form the communication groove 402 at the cover frame 401 . The present embodiment is a method to simply the manufacturing process of a chip package by eliminating such a step. As illustrated in FIG. 9( b ), paste-like adhesive 404 is applied by dispensing so as to surround the range including a through hole 403 and an outer lead 305 , or sheet-like adhesive is cut and attached, whereby a communication hole 705 can be formed. This can manufacture the chip package 203 with a smaller number of steps than that of Embodiment 1. Embodiment 3 [0085] Referring to FIGS. 10( a )( b ) and ( c ), the following describes a still another proposal for a cover frame 401 , a lead frame 301 and the shape to apply adhesive 404 to mount a sensor element 701 on a lead frame assembly 704 more precisely than Embodiment 1. [0086] The communication groove 402 disposed at the cover frame 401 makes the wall thickness of the cover frame 401 nonuniform, and so there is a concern to degrade flatness of the plane on which a sensor element 701 is to be mounted. The communication groove 402 disposed at the lead frame 301 then leads to a concern to degrade the flatness similarly to the case of the cover frame. The communication groove 402 may be disposed at the lead frame 301 , and degradation in flatness of the lead frame 301 may be accommodated with the adhesive 404 . [0087] From the viewpoint of the accuracy in height to mount the sensor element 701 , the adhesive 404 may be applied using sheet adhesive instead of applying on the lead frame by dispensing to suppress variations in dimensions in the lamination direction. However, it is difficult to cut it into the shape surrounding the cavity as in the application area of the adhesive 404 illustrated in FIG. 9( b ), and so adhesive 404 that is made of a porous material that transmits not resin but air is preferably used. The present embodiment enables the lead frame assembly 704 , on which the sensor element 701 can be mounted more precisely. Embodiment 4 [0088] Referring to FIG. 8 , the following describes the transfer molding processing of Embodiment 1 again. The outer lead 305 and the tie bar 304 protrude from the resin part 601 of the chip package 203 to the outside, and so the upper mold for transfer molding 1102 and the lower mold for transfer molding 1103 are manufactured to avoid the outer lead 305 and the tie bar 304 . [0089] As a result, if the cover frame 401 is displaced on the lead frame 301 from a predetermined shape during mounting, there occurs a gap between the outer lead 305 , which is formed by overlapping of the lead frame 301 and the cover frame 401 , and the mold, and then the resin part 601 flows out from this gap. This results in incorrect shape of the chip package 203 . In order to prevent the leakage of resin during transfer molding, the dimension of the gap has to be about 5/1,000 mm, and so very high accuracy is required to mount the cover frame 401 on the lead frame 301 . [0090] Referring to FIG. 11 , the following describes the structure and the manufacturing method to relax restrictions on such an allowable gap dimension. The basic components, structure and manufacturing steps are the same as those of Embodiments 1 to 3. [0091] When the lead frame 301 and the cover frame 401 are bonded with the adhesive 404 , the communication groove 402 , which is formed in any Embodiments 1 to 3, is formed so as to define a closed space inside the cover frame 401 . Next, when the lead frame assembly 704 is molded, the package assembly 602 is formed so as to make sure that the molding range of the resin part 601 is within the range including the entire cover frame 401 , and then when the package assembly 602 is cut out from the outer frame 302 , cutting is performed at the cutting line 1101 of FIG. 11 in the cover frame 401 . Herein, the cutting line 1101 is set so as to pass through a part of the closed space of the adhesion groove. This forms the opening 708 of the communication hole. [0092] This structure prevents the leakage of resin to the outside as long as the upper mold for transfer molding 1102 and the lower mold for transfer molding 1103 cover the range including the communication groove 402 while having the width of about ±0.2 mm at the periphery of the part of the cover frame 401 making up the outer lead 305 , even when there is a displacement of about ±0.1 mm, for example, of the cover frame 401 relative to the lead frame 301 during adhesion, and so the chip package 203 formed can have a correct shape. Embodiment 5 [0093] FIG. 12 illustrates the opening 708 of the communication hole that is obtained after cutting of the outer lead 305 . [0094] In Embodiment 1 or Embodiment 3, when the outer lead 305 is cut after preparing the package assembly 602 , a punch for cutting may crush the upper side face 1201 of the communication hole when pushing the outer lead 305 for cutting, which may block the communication hole 705 . [0095] Let that t denotes the wall thickness of the lead frame and w denotes the width of the communication hole, a part of the communication hole passing through the cutting line 1101 desirably has a relationship of the width of communication hole w≦the wall thickness t. Embodiment 6 [0096] FIG. 13( a ) illustrates an alternative proposal for Embodiment 5 including the package assembly 602 without the outer frame 302 , and FIG. 13( b ) illustrates the state of the opening 708 of the communication hole after cutting the outer lead 305 at the cutting line 1101 . [0097] As illustrated in FIG. 13( b ), a plurality of communication grooves 402 provided can increase the total area of the opening 708 of the communication hole, whereby reliability of the connection between the cavity 703 at the rear face of the diaphragm and the opening 708 of the communication hole via the communication hole 705 can be improved. Embodiment 7 [0098] In Embodiments 1 to 6, the chip component to be mounted on the cover frame 401 is not limited to the sensor element 701 only. The present embodiment illustrates the example where a plurality of chip components including a sensor element is mounted on the cover frame 401 . Referring again to FIG. 13( a ), the following describes the form to mount a plurality of chips. [0099] When a chip 1301 including an arithmetic circuit, for example, in addition to the sensor element 701 , is mounted on a first lead frame, the minimum area of the first lead frame will be increased by the area of the chip 1301 at least. [0100] The present embodiment can be manufactured by the same manufacturing procedure and with the structure of the components and the components used as those of Embodiment 1. However, in the case of a broader communication groove 402 , the cover frame 401 may be deformed due to the injection pressure of thermosetting resin, so that the state of the sensor element 701 and the chip 1301 mounted becomes instable and variations in dimensions to mount chip components in the lamination direction may increase. [0101] Then, a part 1302 free from the communication hole 705 is desirably disposed at an area immediately below the sensor element 701 or the chip 1301 , such an area being disposed partially or entirely on the rear face side of the chip 1301 . Embodiment 8 [0102] Referring again to FIG. 2 that is a cross sectional view of the thermal flow meter, the following describes a method to improve the accuracy in position to mount the sensor element 701 to reduce variations in characteristics of the thermal flow meter 100 . [0103] The positional accuracy of the sensor element 701 in the sub-passage 101 of the thermal flow meter 100 affects the variations in characteristics of the thermal flow meter 100 . The chip package 203 is bonded to the housing member 201 and the cover member 202 that make up the sub-passage 101 . This means that, in order to mount the sensor element 701 in the sub-passage 101 precisely, variations in dimensions between the surface of the resin part 601 and the surface of the sensor element 701 that is at the bonding face with the housing member 201 and the cover member 202 have to be minimized. [0104] Referring next to FIG. 8( b ), the following considers the integration of variations in dimensions inside the chip package 203 . The positional relationship between the sensor element 701 and the resin part 601 depends on the transfer molding step. At this time, since the lead frame 301 is set to be sandwiched between the upper mold for transfer molding 1102 and the lower mold for transfer molding, the lead frame surface will serve as a reference for the dimensional tolerance. [0105] This means that factors of variations in dimensions between the surface of the resin part 601 and the sensor element 701 in the lamination direction during mounting include the flatness of the face to mount the lead frame 301 thereon, variations in thickness of the adhesive 404 , variations in thickness of the cover frame 401 , flatness of the bonding face between the cover frame 401 and the lead frame 301 , flatness of the face of the cover frame 401 to mount the sensor element 701 thereon, and variations in thickness of the die-bond material 501 . [0106] In the present embodiment, the cover frame 401 is bonded to the opposite side of Embodiment 1 to alleviate the factors of variations in the lamination direction of the sensor element 701 during mounting, and the die-bond material 501 is directly applied to the lead frame 301 , followed by mounting of the sensor element 701 . This can reduce the factors of variations in the lamination direction of the sensor element 701 during mounting to the flatness of the face to mount the lead frame 301 thereon and the variations in thickness of the die-bond material 501 only. The following describes the manufacturing procedure, the components included and the structure of the components with reference to FIGS. 14 to 19 . [0107] Firstly, similarly to Embodiment 1, the lead frame 301 and the cover frame 401 are prepared (in the present embodiment, the aforementioned first lead frame and second lead frame are called a lead frame and a cover frame, respectively). FIG. 14( a ) describes the structure of the lead frame, FIG. 14( b ) describes the shape of the lead frame and the adhesive 404 to bond the cover frame 401 and the lead frame 301 , and FIG. 14( c ) describes the structure of the cover frame 401 . [0108] The lead frame 301 includes a through hole 403 that is disposed immediately below a cavity 703 under the diaphragm of the sensor element 701 , a communication groove 402 to release air from the cavity 703 below the diaphragm, which is formed by etching or pressing, an outer frame 302 , a die pad 303 to mount an electronic component such as a sensor element 701 thereon, a tie bar 304 to joint the outer frame to the die pad 303 so as not to cause displacement of these components due to influences from resin flow during transfer molding, and an outer lead 305 to serve as a terminal of the chip package 203 . This structure is preferable because it enables a simple configuration just by cutting the outer peripheral shape surrounding the communication groove 402 to process a cover frame 401 . [0109] FIG. 15 illustrates the state where the lead frame 301 and the cover frame 401 are bonded with the adhesive 404 . [0110] The adhesive 404 is applied at an area between the lead frame 301 and the cover frame 401 and surrounding an adhesion groove 405 . At this time, since there is no need to provide an internal range of the application of the adhesive 404 where the adhesive 404 is not to be applied, sheet-form adhesive 404 is used preferably, whereby the step can be very simple. [0111] FIG. 16 illustrates the state where the sensor element 701 is structurally or electrically bonded to the lead frame assembly 704 , where FIG. 16( a ) is a front view and FIG. 16( b ) is a cross sectional view. [0112] A die-bond material 501 that is Ag paste or epoxy-based material is applied on the lead frame 301 so as to surround the through hole, and then sensor element 701 is die-bonded, followed by heating of the die-bond material 501 and the adhesive 404 for curing. [0113] Subsequently, an electrode extraction part 42 on the sensor element 701 and a bonding part 503 on the lead frame 301 are connected by wire bonding using Au wire 504 . [0114] The subsequent steps to prepare the chip package 203 are the same as those in Embodiment 1. [0115] Packaging of the sensor element 701 with such structure, components included, manufacturing procedure similarly to Embodiment 1 allows the cavity 703 below the diaphragm to be cut off from the interior of the intake pipe 140 , and so concern about water droplet and contamination to reach there can be removed. Further, the space below the diaphragm and the atmosphere can communicate with each other, whereby a concern about the deformation of the diaphragm 702 can be removed, which is due to a pressure difference between the surface side and the rear face side of the diaphragm, and so a change in values of resistance due to Piezoresistive effect, i.e., a change in characteristics can be reduced. [0116] Further, the sensor element 701 can be packaged precisely, which can contribute to suppress variations in characteristics of the thermal flow meter 100 . [0117] Embodiments 5, 6 and 7 may be combined, whereby needless to say, a chip package can be manufactured more precisely. Embodiment 9 [0118] Referring to FIGS. 17( a ) ( b ) and ( c ), the following describes a cover frame 401 , a lead frame 301 and the shape to apply adhesive 404 in Embodiment 9. Embodiment 8 requires etching or pressing at the cover frame 401 to form the components making up the lead frame assembly 704 . The present embodiment can eliminate such a step, whereby the manufacturing process of a chip package 203 can be simplified. [0119] As illustrated in FIG. 17( b ), adhesive 404 is applied so as to surround the range including a through hole 403 and an outer lead 305 , whereby a communication hole 705 can be formed. This can manufacture the chip package 203 with a smaller number of steps than that of Embodiment 8. Embodiment 10 [0120] Referring to FIGS. 18( a )( b ) and ( c ), the following describes a cover frame 401 , a lead frame 301 and the shape to apply adhesive 404 in Embodiment 10. [0121] The communication groove 402 disposed at the lead frame 301 in the above Embodiment 8 makes the wall thickness of the lead frame 301 nonuniform as illustrated in FIG. 16 , and so there is a concern to degrade flatness of the plane on which a sensor element 701 is to be mounted. [0122] Then, as illustrated in FIG. 18 , the communication groove 402 of the present embodiment is disposed at the cover frame 401 to accommodate the degradation in flatness of the cover frame 401 with the adhesive 404 . [0123] Further, from the viewpoint of the accuracy in height to mount the sensor element 701 , the adhesive 404 may be applied using sheet adhesive instead of applying on the lead frame by dispensing to suppress variations in dimensions in the height direction. However, it is difficult to cut it into the shape surrounding the cavity as in FIG. 14( b ) using the sheet adhesive, a shape without a hole as in FIG. 18( b ) is preferable. [0124] Then the adhesive 404 that is made of a porous material that transmits not resin but air is preferably used. Embodiment 11 [0125] Embodiments 1 to 10 describe the lead frame assembly 704 including the lead frame 301 , the adhesive 404 , the cover frame 401 , the sensor element 701 , the die-bond material 501 and the Au wire 504 as a minimum configuration, and the following describes the present embodiment as an alternative proposal that does not include the cover frame 401 to reduce the number of components. The basic steps are the same as those in Embodiment 1 and Embodiment 8. [0126] FIGS. 19 to 22 illustrate the structure of a lead frame 301 in the present embodiment. In these drawings, (a) is a front view of the lead frame 301 and (b) is a cross-sectional view including the center of the through hole 403 . [0127] Firstly the lead frame 301 illustrated in FIG. 19 is prepared. Similarly to the aforementioned lead frame 301 , the lead frame 301 includes the die pad 303 , the tie bar 304 , a dam bar 306 , the outer lead 305 and the outer frame 302 . Then, the entire lead frame 301 is divided into a main frame 2024 and a tab lead 2023 at a mountain folding line 2201 as the border, where the die pad 303 , the tie bar 304 , the through hole 403 in the range including at least a part of the cavity under the diaphragm when the sensor element 701 is mounted on the die pad 303 , and the tab lead 2023 are disposed on the main frame 2024 side. On the tab lead 2023 side, the communication groove 402 is formed as a recess by pressing performed from the face on the opposite side of the sensor-element mounting face toward the sensor-element mounting plane, and the through hole 403 and the communication groove 402 are disposed to be overlapped each other when the lead frame is folded by 180 degrees along the mountain folding line 2201 . Adhesive is then applied to the main frame 2024 side or the tab lead 2023 side so as to surround the communication groove 402 entirely, followed by bending of the lead frame along the mountain folding line 2201 , whereby the tab lead 2023 and the main frame 2024 are bonded with the adhesive 404 . The subsequent steps following the mounting of the sensor element 701 are the same as those in Embodiment 8, where the mountain folding line 2201 is used as a valley folding line, and a communication groove 402 is disposed at the main frame 2024 and a through hole 403 is bored at the tab lead 2023 similarly to Embodiment 8. [0128] Considering the cover frame 401 in Embodiments 2 to 7 and Embodiment 9 to 10 as the tab lead 2023 for replacement, the members making up the communication groove 402 and the through hole 403 and the range to apply the adhesive 404 may have the same configuration, whereby the same advantageous effects from these embodiments can be achieved for the problems to be solved by the embodiments. [0129] FIGS. 21 and 22 illustrate an example where the communication groove 402 of the present embodiment is formed by half etching, from which the same advantageous effects can be obtained similarly. Embodiment 12 [0130] In Embodiments 1 to 11, when cutting out the chip package 203 and the outer lead 305 from the outer frame 302 of the package assembly 602 , the outer lead 305 making up the communication hole 705 is disconnected, whereby the opening 708 of the communication hole is formed. However, when disconnecting the outer lead 305 to make up the communication hole 705 , there is a concern to crush the communication hole 705 with a punch for disconnection, thus blocking the opening 708 of the communication hole. To avoid this concern, the present embodiment proposes another method to form the opening 708 of the communication hole by way of a typical example of the manufacturing procedure and the structure illustrated in FIG. 1 , with reference to FIGS. 23 to 26 . [0131] Firstly a lead frame 301 and a cover frame 401 are prepared. The lead frame 301 has the same configuration as that of the lead frame in the aforementioned Embodiment 1. [0132] Referring to FIG. 23( a ), the configuration of the cover frame 401 is described below. To release air from the cavity 703 below the diaphragm, the cover frame 401 includes a through hole 403 disposed immediately below the diaphragm, a communication groove 402 that is formed by half etching or pressing, and at least one or a plurality of lead frame openings 2301 to connect the communication groove 402 and the sensor-element mounting face. [0133] FIG. 24( a ) is a front view illustrating the state where the lead frame 301 and the cover frame 401 are bonded with adhesive 404 , and FIG. 24( b ) is a cross-sectional view thereof. When the lead frame 301 and the cover frame 401 are bonded with the adhesive 404 , the communication groove 402 leading to the through hole 403 is formed. [0134] FIG. 25( a ) is a front view illustrating the state where the sensor element 701 is structurally or electrically bonded to the lead frame assembly 704 , and FIG. 25( b ) is a cross sectional view thereof. [0135] After applying a die-bond material 501 made of Ag paste or thermosetting adhesive so as to surround the through hole on the cover frame 401 , the sensor element 701 is die-bonded, and the die-bond material and the adhesive are heated in an oven for curing. [0136] Then, an electrode extraction part 42 on the sensor element 701 and a bonding part 503 on the lead frame are connected by wire bonding using Au wire 504 . [0137] FIG. 26 illustrates the state where molding is performed for the lead frame assembly 704 on which the sensor element 701 has been mounted. [0138] The lead frame assembly 704 on which the sensor element 701 has been mounted, which is prepared by the procedure till FIG. 26 as stated above, is set in a mold for transfer molding, and resin such as epoxy or polyamide is poured into the mold by transfer molding, thus forming a package assembly 602 . At this time, an opening 2301 of the lead frame is covered with a pin 2602 that is larger than the opening 2301 . This can prevent the transfer molding resin from flowing into the communication hole 705 , and the place covered with the pin 2602 becomes a package opening 2601 after releasing of the mold for transfer molding, and the combination of the opening 2301 of the lead frame and the package opening 2601 forms an opening 708 of the communication hole of the package assembly 602 . The subsequent manufacturing procedure to prepare the chip package 203 is the same as those in Embodiment 1. [0139] Such manufacturing procedure and configuration can form the opening 708 of the communication hole without cutting the outer lead 305 making up the communication hole 705 , thereby removing a concern to block the communication hole during disconnection of the outer lead 305 . [0140] The present embodiment can be applied to Embodiments 2 and 3 as well as Embodiments 7 to 11, from each of which the same advantageous effects can be obtained. Embodiment 13 [0141] Referring to FIG. 27 , Embodiment 13 is described below. The present embodiment includes additional processing performed to the lead frame 301 so as to form a communication hole 705 and a through hole 403 . When the wall thickness of a material for the lead frame is sufficiently thick of 2 mm or more, for example, a hole can be bored there in the thickness direction using a drill of about φ 1 mm. [0142] A horizontal hole vertical to the face on which the sensor element 701 is to be mounted is bored at a die pad to be a through hole 403 . Another horizontal hole is bored from the outside of the outer frame 302 so as to intersect the through hole 403 and penetrate through the outer lead 305 in the direction parallel to the sensor-element 701 mounting face to be a communication hole 705 . The thus prepared lead frame 301 is a lead frame 704 , and a chip package 203 is manufactured by the same steps as those in Embodiment 1. [0143] The present embodiment can reduce the number of components as compared with Embodiments 1, 8 and 11, and the lead frame assembly can be formed of materials having minimum sizes. As compared with the case of bonding lead frames or separate members to form a communication hole as in Embodiments 1 to 11, there is no concern to block the communication hole 705 during transfer molding or during cutting of the outer lead, and so reliability of the connection between the cavity 703 below the diaphragm and the opening 708 of the communication hole can be improved. Embodiment 14 [0144] FIG. 28 illustrates another proposal to improve the reliability of connection between the cavity 703 below the diaphragm and the opening 708 of the communication hole, referring to FIG. 27 . Embodiment 8 illustrates the configuration of disposing the cover frame 401 at the rear face of the communication hole of the lead frame 301 . The present embodiment includes, instead of the cover frame 401 , a pipe-formed member 2701 under the through hole that is bonded with adhesion or by welding. The pipe-formed member may be made of soft metal such as copper or a resin material having a melting point from about 100° C. to 200° C. or higher that is a temperature during injection for transfer molding, for example. After bonding to the lead frame 301 , the pipe-formed member 2701 is bent toward the direction where the circuit chamber of the thermal flow meter 100 is disposed, which then becomes a lead frame assembly 704 . The subsequent steps to manufacture the thermal flow meter are the same as those in Embodiment 8. [0145] This can avoid a concern about the adhesive 404 protruding over the communication hole 705 , which is due to the communication hole 705 made up of two members, and so the cavity 703 below the diaphragm and the opening 708 of the communication hole can be connected more reliably. Embodiment 15 [0146] FIG. 29 is an enlarged cross-sectional view of a plane that passes through the center line of the through hole 403 . In the case of Embodiments 1 to 13, if the amount of the die-bond material 501 applied is not appropriate when the sensor element 701 is die-bonded on the lead frame 301 , the cover frame 401 or the tab lead 2023 , the die-bond material 501 will flow out to the through hole 403 as in FIG. 29( a ) and may block the through hole 403 . To prevent this, a die-bond material receiver 2801 is disposed so as to surround the through hole 403 as in FIG. 29( b ). The die-bond material receiver 2801 is a recess that is lower than the applied face of the die-bond material 501 (dam structure), and so variations in the amount of the die-bond material 501 applied can be accommodated with the volume of the recess. [0147] The present embodiment alleviates a concern about the die-bond material 501 to stick out over the through hole 403 , and so the cavity 703 below the diaphragm and the opening 708 of the communication hole 705 can be connected more reliably. REFERENCE SIGNS LIST [0000] 4 , 360 Flow detection part 5 Driving circuit 6 Characteristic adjusting circuit 7 Heater resistor 8 , 10 Fixed resistor 9 Non-thermal resistor 11 to 14 Temperature sensor (temperature detection resistor) 15 Operational amplifier 26 Constant voltage source 42 Electrode extraction part 99 Flange part 100 Thermal flow meter 101 Sub-passage 102 Circuit chamber 103 Connector part 104 Thermosetting adhesive 105 Upstream side opening 106 Downstream side opening 107 , 701 Sensor element 108 Ventilation hole 109 Atmosphere outside intake pipe 110 Intake air 111 Connector lead 112 Aluminum wire 140 Intake pipe 201 Housing member 202 Cover member 203 Chip package 301 Lead frame 302 Outer frame 303 Die pad 304 Tie bar 305 Outer lead 306 Dam bar 331 Heater 332 Upstream side thermosensitive resistor 333 Downstream side thermosensitive resistor 401 Cover frame 402 Communication groove 403 Through hole 404 Adhesive 501 Die-bond material 503 Bonding part 504 Au wire 601 Resin part 602 Package assembly 702 Diaphragm 703 Cavity 704 Lead frame (lead frame assembly) 705 Communication hole 708 Opening of communication hole 1101 Cutting line of outer lead making up communication hole 1102 Upper mold for transfer molding 1103 Lower mold for transfer molding 1201 Upper side face of communication groove 1301 Chip 1302 Part without communication hole 705 2023 Tab lead 2024 Main frame 2201 Mountain folding line 2202 Position to mount sensor element 2301 Lead frame opening 2601 Package opening 2602 Pin 2701 Pipe-formed member 2801 Die-bond material receiver

Airflow measuring apparatus compring: sub-passage that takes in part of flow of fluid flowing through an intake pipe; sensor element that is disposed in the sub-passage to measure the flow of fluid; a circuit part that converts the flow of fluid detected by the sensor element into an electric signal; connector part connected to the circuit part to output a signal externally; and casing that supports the sensor element and the circuit part, the sensor element being disposed in the intake pipe. The sensor element includes a cavity disposed at a semiconductor substrate, a diaphragm including a thin film part that covers the cavity. The sensor element on a lead frame have surfaces that are mold-packaged with resin so that a diaphragm of the sensor element and part of the lead frame are exposed. One hole is disposed at the lead frame for communication between the cavity and exterior.

BACKGROUND OF THE INVENTION [0001] The present invention relates to a method and apparatus for the simultaneous centralized control of capsule-like yarn brakes of several twist spindles of a two-for-one twisting machine. [0002] DE 44 08 262 C2 discloses an apparatus for the central control of a capsule-like yarn brake of a twisting machine, especially a two-for-one twisting machine. This conventional apparatus includes a control device and a common compressed air unit which is communicated with the twist spindles via connecting units each associated with a respective twist spindle and operable to deliver air pulses to a pressurized air cylinder coupled to a brake ring of the respective twist spindle, the control device controlling the common compressed air unit to deliver pressurized air pulses to the pressurized air cylinders, whereby the pressurized air cylinders, upon receipt of the air pulses, effect an axial displacement of the rotatable brake rings of all of the capsule-like yarn brakes over a predetermined extent. [0003] DE PS 32 43 157 discloses a twist spindle having a capsule-like yarn brake, which is supported between upper and lower brake rings. The upper brake ring is mounted to a support body at the lower end of a yarn intake conduit of a twist spindle and is resiliently biased by a spring in the direction of the lower, second brake ring. The support body is provided with a plurality of support shoulders distributed around its circumference at different axial positions so that a respective one of the support shoulders is supported on a stationary detent. An adjustment of the braking force of the capsule-like yarn brake is effected in a manner such that the yarn intake conduit is raised against the force of the spring which biases the support body and, thereafter, the yarn intake conduit is rotated through a pre-determined angular range of traverse such that another support shoulder of the support body comes to rest against the detent. This conventional device is thus directed to an individual adjustment and, especially, a manual individual adjustment, of each individual capsule-like yarn brake. SUMMARY OF THE INVENTION [0004] The present invention offers a solution to the challenge of providing a method and an apparatus for the simultaneous centralized controlled adjustment of the capsule-like yarn brakes of a plurality of twist spindles of a two-for-one twisting machine such that the need for a dedicated pressurized air system can be avoided. [0005] Summarizing the prevalent characteristics of the present invention, the present invention is particularly characterized in that it exerts, in a purely mechanical operation implemented via a plurality of yarn balloon guides commonly supported on a support frame, a sufficiently high pressure on the yarn intake conduits of a plurality of twist spindles such that the yarn intake conduits, which each support one of the two respective brake rings of the respective twist spindle, are axially displaced against the bias of a spring force to an extent such that a brake ring rotation advances the brake ring to a different axial position relative to the other, second respective brake ring following each release of the yarn intake conduit from the axial pressure thereon. [0006] An embodiment of the present invention is described in the following description taken in connection with the figures of the drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0007] [0007]FIG. 1 is a sectional view of a two-for-one twisting machine having a plurality of yarn balloon guides commonly mounted on a yarn guide frame, which is movable upwardly and downwardly; [0008] [0008]FIG. 2 is an enlarged sectional view of a twist spindle having a hollow shaft in which a capsule-like yarn brake is disposed; [0009] [0009]FIGS. 3 a - 3 c are each an enlarged perspective view of a portion of the adjustment unit at a respective different position thereof during movement of the adjustment unit to adjust the braking force of the twist spindle relative to a stationary detent; [0010] [0010]FIG. 4 is an enlarged perspective view of a variation of the one embodiment of the adjustment unit; and [0011] [0011]FIG. 5 is an enlarged perspective view of a twist spindle having a variation of the embodiment of a yarn balloon guide. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0012] [0012]FIG. 1 shows a sectional view of a two-for-one twisting machine which supports the yarn balloon guides 9 of a plurality of twist spindles S arranged in neighboring relation to one another, the yarn balloon guides 9 being commonly mounted to a common yarn guide frame 11 which is movable—in a not illustrated guide—upwardly and downwardly parallel to the axes of the twist spindles S in the direction of the double arrow F 1 . [0013] The yarn guide frame 11 is suspended by means of suspension hangers 12 on a shaft 13 , which is rotatably driven by a rotation drive 14 operatively coupled to a motor 15 . The downward movement of the yarn guide frame 11 is effected under the influence of gravity by corresponding controlled actuation of the motor 15 . The possibility thus exists to position the yarn balloon guides 9 at differing heights over the yarn intake conduits 3 , whereby, to exert an influence on the yarn twisting process, the formation of yarn balloons can be controlled. In accordance with the present invention, the yarn balloon guides 9 can be displaced downwardly through corresponding adjustment of the yarn guide frame 11 to such an extent that the yarn balloon guides 9 exert a downward pressure on the yarn intake conduits 3 of a plurality of the twist spindles S, whereby the yarn intake conduits 3 are pressed downwardly. In this manner, as will be hereinafter described, the possibility exists to provide a centrally controlled adjustment of the yarn brakes of a plurality of spindles S arranged in neighboring relationship to one another. [0014] [0014]FIG. 2 shows a portion of the hollow shaft 2 of a rotationally symmetric housing 16 in which is disposed a capsule-like yarn brake 11 and an adjustment unit 18 which is responsive to downward pressure on the yarn intake conduit 3 , the adjustment unit 18 being operable to effect a variation of the braking force of the capsule-like yarn brake 11 . The adjustment unit 18 is secured to the bottom end of the yarn intake conduit 3 and comprises a cylindrical housing 27 open towards its bottom for receipt therein of a helical spring 28 which biases the adjustment unit 18 upwardly. [0015] The housing 16 is closed on its topside by a threaded cover 19 through which the yarn intake conduit 3 is guided outwardly of the housing 16 . The capsule-like yarn brake 11 includes a bullet-like brake which, in conventional manner, is comprised of two displaceable tube portions 11 . 1 and 11 . 2 biased by a spring to move axially away from one another and each of which includes a cup or cap-shaped end portion. The lower tube portion 11 . 2 is supported against a brake ring 20 , which is disposed in a brake ring carrier 21 disposed in an axial guide or groove 21 . 1 . The brake ring carrier 21 , which is supported against a helical spring 22 , is sealingly guided in a housing bore 16 . 2 formed in the housing 16 such that, for purposes of effecting a pneumatic yarn threading or intake of yarn, an under-pressure is created below the yarn ring carrier 21 so as to effect downward movement of the yarn ring carrier. The lowered yarn ring 20 thus releases the bullet-like yarn brake 11 to fall whereupon it is then caught by a support ring 16 . 3 stationarily mounted in the housing; the support ring 16 . 3 has a partial opening 16 . 31 such that a yarn introduced through the yarn intake conduit 3 can be suctioned in through the yarn intake 8 into the bore 21 . 1 and guided past the released bullet-like brake 11 . A yarn threading system of this type is described in DE 44 08 262 C2 and is, in any event, the basic configuration of the yarn intake assembly as described in the hereinafter-described adjustment unit 18 . [0016] A first annular upper toothed rim 40 is disposed on the adjustment unit 18 above the housing 27 and a second annular lower tooth rim 41 is disposed above the housing 27 as well. The upwardly directed teeth of the lower toothed rim 41 form therebetween axial spaces in the form of openings/slots whose bases or bottoms form notches or, respectively, support shoulders which are distributed about the circumference of the toothed rim at differing axial heights therearound and each notch or support shoulder is engaged upon its turn by a radially inwardly projecting detent 29 as a function of the rotational position of the adjustment unit 18 . [0017] The downwardly directed teeth of the upper-toothed rim 40 form therebetween axially extending slots opening downwardly or, respectively, form downwardly opening notches. [0018] Reference is now had to FIGS. 3 a - 3 c for a description of the configuration of the teeth of the two toothed rims 40 and 41 ; the arrow F 2 indicates the rotational direction of the adjustment unit 18 . [0019] The flanks 40 . 1 and 41 . 1 of the teeth of the upper and lower toothed rims 40 and 41 which extend in the rotational direction F 2 have substantially axial extents. The down sloping flanks 40 . 2 or, respectively, 41 . 2 of the upper and lower toothed rims 40 and 41 are configured as respective rising or falling angled surfaces which form an angle of approximately 45° relative to the rotational direction. The tips or peaks of the teeth of the upper-toothed rim 40 are offset from the tips or peaks of the teeth of the lower toothed rim 41 in the rotational direction by an amount which is slightly greater than the diameter of the detent 29 . [0020] [0020]FIG. 3 a shows an operational condition in which the lower toothed rim 41 is engaged by the detent 29 such that the detent is seated in a notch I between two neighboring teeth of the lower toothed rim with the portion of the adjustment unit 18 comprised of the lower toothed rim 41 being upwardly biased by the spring 28 . If the adjustment unit 18 is displaced downwardly in the direction of the arrow F 3 via a downward pressure on the yarn intake conduit 3 , the detent initially assumes the position shown by the broken lines 29 ′ seen in FIG. 3 b. Upon further downward pressure on the yarn intake conduit 3 , the detent traverses along the toothed flank 40 . 2 extending away from the rotational direction f 2 to thereafter achieve the intermediate position 29 ″ shown in FIG. 3 c in correspondence with the partial rotation of the adjustment unit 18 in the direction of the rotation direction F 2 . The movement of the detent 29 relative to the adjustment unit 18 follows thus along the path of the bent arrow F 5 shown in FIG. 3 a. It is to be understood that the stationary detent 29 does not axially change its position but, rather, the adjustment unit 18 undergoes a partial rotation during this process. [0021] If, thereafter, the yarn intake conduit 3 is again released, the adjustment unit 18 is again biased upwardly, as seen in FIG. 3 c, in the direction of the arrow F 4 due to the biasing action of the spring 28 so that the detent 29 —following the path shown by the bent arrow F 6 —seats into the next following notch 11 , whereby there follows a sliding movement of the detent 29 along the flank 41 . 2 in the direction of the rotation direction F 2 upon a further partial rotation of the adjustment unit 18 . [0022] By virtue of the lowering and subsequent release of the yarn intake conduit 3 and, thus, of the adjustment unit 18 , there follows a sectional rotation of the adjustment unit 18 in the rotational direction F 2 . Since each notch is lower than the immediately preceding notch, it follows, as the detent 29 seats into the respective next following notch, that the brake ring 23 is disposed in progressively lower positions following each operation to lower and release the yarn conduit 3 , thus leading to an increase in the braking force. [0023] The braking force can thus be adjusted in a step-wise manner through individual downward pressure and release sequences of the yarn intake conduit 3 until the braking force has been increased to a maximum value, which value is predetermined by the depth of the deepest notch in the lower toothed rim 41 . [0024] Through multiple sequential actuation—that is, multiple actuation involving downward pressure and release of the yarn intake conduit 3 —the yarn braking force can be increased until the detent 29 is eventually seated in the deepest notch of the lower toothed rim 41 . [0025] By sequential or subsequent activation of the yarn intake conduit 3 , the detent 29 is moved into the next following—that is—the highest disposed notch—of the lower toothed rim 41 , which corresponds to the braking force adjustment position of the lowest value. [0026] The toothed rims 40 ′, 41 ′, as seen in FIG. 4, can be configured as lower components freely rotatable relative to the remainder of the adjustment unit 18 but not, however, adjustable relative thereto in the axial direction, with the toothed rims 40 ′, 41 ′ being supported by, from below, a collar of the housing 27 and, from above, a detent body 60 which is securely mounted via, for example, a threaded screw 61 , on the yarn intake conduit 3 . [0027] The yarn balloon guides can alternatively be configured to be self-centering with respect to the associated yarn intake conduits 3 —e.g., as truncated ball-shaped yarn balloon guides 9 ′, as seen in FIG. 5. [0028] The specification incorporates by reference the disclosure of German priority document DE 100 45 909.9. [0029] The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.

A method and apparatus for the simultaneous centralized controlled adjustment of the braking force of yarn brakes of a plurality of twist spindles of a two-for-one twisting machine are provided, whereby each twist spindle is of the type having, in its hollow shaft, a yarn brake supported between two brake rings with one of the brake rings being rotatable in response to a downward axial pressure thereon in a manner such that the brake ring undergoes a discrete axial displacement to a new axial position. A support frame to which yarn balloon guides are mounted exerts a downward axial force such that the yarn balloon guides simultaneously exert downward axial pressure on the yarn intake conduits of the twist spindles which, in turn, effects axial displacement of the rotatable and axially adjustable brake ring on the yarn intake conduit of each twist spindle into new axial positions.

Detailed Description of the Invention CROSS-REFERENCE TO OTHER APPLICATION [0001] This application claims priority from U.S. Provisional Application 60/408,096 filed Sep. 3, 2002, which is hereby incorporated by reference. BACKGROUND AND SUMMARY OF THE INVENTION [0002] The present application relates to computer architecture, and particularly to techniques for interfacing added modules into existing e-mail programs. [0003] Background: Computer Communications [0004] "Computer communications" was regarded as a specialized area in the 1960s or so, but now most communication is converging to a paradigm of data communication. The endpoints of data communication are not necessarily computers, but can be audio, video, or image interfaces, sensors, switches, control units, or many kinds of "smart" devices. Thus the established engineering principles of computer networks are becoming applicable to a wide range of applications. [0005] Background: Networks, Packets, and Protocols [0006] Computer network structure and operation is one of the basic areas of computer science, and a vast amount of literature has been published. One of the basic ways to structure communications over a network is to use packets of data, as in the pioneering "packet-switched" ARPANET which evolved into the Internet. [0007] Background: Hashing [0008] One of the simplest types of data translation is "hashing," where data is reversibly transformed in a way which randomizes the statistical distribution of bytes. Hashing can be a useful way to disarm viruses and/or provide a more nearly stochastic distribution of data. (Equalizing symbol distribution can help in increasing S/N ratio of data transmission.) [0009] Background: Filtering [0010] A special kind of data translation is filtering, where data is transformed conditionally depending on a certain test. "Packet filtering" is a more specific term for content-dependent routing. Any router performs address-dependent routing, but filtering implies that the data in the packet is analyzed in some fashion to affect routing. (For example, packets in which a virus signature is found may be discarded.) [0011] Background: Digital Signature and Identification [0012] Public-key algorithms (RSA etc.) can be useful for authenticating digital documents. An extension of this is for identification of the specific human who has chosen to authenticate the document. There are many circumstances where it would be useful for persons communicating over the Internet (or over a network) to be able to identify themselves reliably. For example, in arm's-length Internet sales, it can be useful to definitely identify the other party. For another example, electronic publishing over the internet becomes much more practical if working access can be limited to only those users who have paid for it. For another example, some users would like to filter incoming email to exclude mailings (such as spam) which are not tagged with a reliable certificate of origin. [0013] Keys used for digital signatures are a very long series of bits, which can be represented as long series of alphanumeric characters. Unlike Personal Identification Numbers (PINs), it is simply not feasible for individuals to remember them. For access control, such key data is typically stored in a chip (or other electronic memory), which can be embedded in a plastic card, or in another physical object such as a ring. [0014] Background: Interfacing to Programs [0015] In the past decade it has become increasingly difficult to introduce innovative business software products for the personal computer market. Such products must be able to interface to the widely used software application packages, and this is not always easy. In particular, it is important for communications-related software to be able to interface to Outlook, Notes, and GroupWise, and none of these are easy to program for. (The documentation provided to third-party developers is unclear and difficult to use.) [0016] Computer communications are a somewhat unusual area of software development, in that many functions may need to be combined. A user's full-range email program should be able to handle (using calls to other programs as needed) various compression or authentication formats, various image formats, various audio formats, various HTML or XTML extensions, various drawing formats, various special fonts, virus-checking, and other new functions as they come up. (For example, the secure communications capabilities of PGP were integrated into some email programs, such as Eudora, long before PGP was available in other email programs.) As this list indicates, the boundary between browser functions and email functions has blurred somewhat in the last decade, and this trend may continue. Thus, since email handling necessarily involves so many different data types and data operations, smooth integration is particularly important. [0017] Background: Dongles [0018] A recurrent theme in the software industry has been the desire to find some way to make copied software unusable. One of the earliest ways to do this was the "dongle," in which a physical package containing an electronic key was attached to a port of the computer. [0019] Data Translation Architecture [0020] The present application describes a new system architecture for adding in functionality, and particularly for adding data translation functions between a communications program and its target (e.g. the outside world). The preferred embodiment achieves this without any need to intrude on management of the TCP/IP stack; instead, data for communication is simply addressed to a reserved (preferably loopback) address, and is snooped by a "translation agent" (software routine or hardware) either when it is being sent to the network interface unit or when it is echoed back. The translation agent can provide authentication, privacy, data reformatting, or other such functions. In alternative embodiments these ideas can be used in digital systems which are not computers, or can be used as part of a firewall or gateway, or to interface between networks using different protocols, or used in other analogous ways. [0021] The disclosed innovations, in various embodiments, provide one or more of at least the following advantages: [0022] simple interface into existing software; [0023] added IP address uses without added stack handling; [0024] good invisibility to viruses; [0025] easy integration, even with undocumented e-mail programs; [0026] can secure all non-protocol-level data on any TCP/IP port; [0027] transparent to applications which use TCP/IP; [0028] device, platform and operating system independent; [0029] independent of any specific methodology for securing data; [0030] recipient-dependent email modifications are easy. BRIEF DESCRIPTION OF THE DRAWING [0031] The disclosed inventions will be described with reference to the accompanying drawings, which show important sample embodiments of the invention and which are incorporated in the specification hereof by reference, wherein: [0032] [0032]FIG. 1 shows a generic overview of the translation-assistant. [0033] [0033]FIG. 2 shows an example of implementation of the Translation Agent into an existing application environment. [0034] [0034]FIG. 3 shows a generic TCP/IP session. [0035] [0035]FIG. 4 shows a client server environment using some of the disclosed inventions. [0036] [0036]FIG. 5 shows an environment whereby TA secures the transmission between two TA client applications without Server interdiction. [0037] [0037]FIG. 6 shows secure data transmission in a peer-to-peer environment. [0038] [0038]FIG. 7 shows the client to server secure relationship, and [0039] [0039]FIG. 8 shows the server to client relationship. [0040] [0040]FIG. 9 is a flowchart for the TA examining and processing for transmitting data. [0041] [0041]FIG. 10 is a flowchart for the TA examining and processing of received data. [0042] [0042]FIG. 11 is a sample of the devices that can be secured with TA. [0043] [0043]FIG. 12 illustrates the interface between Translation Agent and application software in a device. [0044] [0044]FIG. 13 gives an overview of the installation process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0045] The numerous innovative teachings of the present application will be described with particular reference to the presently preferred embodiment (by way of example, and not of limitation). [0046] Translation Agent (TA) is an architecture for modifying (e.g. securing data in the Telecommunications Control Protocol and Internet Protocol (TCP/IP) data stream. TA is platform, operating system and device independent. TA is independent of any specific technology for securing or otherwise modifying the data. [0047] TA utilizes the TCP/IP "loopback" address 127.0.0.2 and/or other class A addresses in that range to implement a procedure whereby TA can become a pseudo-server on and within the physical device. [0048] TA is then able to monitor all or specific ports on the device and secure the data as it is transmitted or unsecure the data as received. [0049] TA is independent of specific protocols such as SMTP ("Simple Mail Transport Protocol"), POP3 ("Post Office Protocol 3"), FTP, HTTP etc. TA examines the data, passing protocol level information without modification and secures the data portion of the transmission. [0050] TA processes and secures the data based on the requirements and capabilities of the specific method used for securing the data. [0051] TA is designed to be transparent to other applications and virus checking applications. [0052] The TA architecture provides an open framework into which many different algorithm implementations can be inserted as modules. For example, for converting unsecured data to secure data and vice versa, the TA architecture can support insertion of e.g. LZW, DES, DES-3, Rijndael, Blowfish, TwoFish, PGP, RSA, etc. Algorithms used can be, for example, streaming or block-oriented, symmetric or asymmetric. [0053] The Translation Agent architecture is modular to the extent that a wide variety of existing encryption (or other) algorithms can be "plugged in" to the Translation Agent. This means that any existing or later-developed algorithm or system can be used if any sizeable group of users demands it. The amount of administrative overhead created by these systems is reduced, since the activities performed within the Translation Agent module are unseen by the user. This is particularly beneficial in corporate IT departments, where a considerable amount of support is usually necessary to make this systems function properly. [0054] [0054]FIG. 1 shows a generic overview of the TA's function in a device 101 using TCP/IP. (The device 101 can be, for example, a personal computer, or alternatively can be a variety of other device types as discussed below.) The configuration of a software application 100 is modified to send and/or receive TCP/IP packets using a reserved (e.g. "loopback") TCP/IP address 102 in place of its original TCP/IP settings. TA module 103 is configured to listen on the reserved address 102 specified for this application. (Note that multiple reserved addresses can be specified for multiple applications.) TA module 103 then initiates sessions, using the application's data, on another TCP/IP connection 106. (The TA module 103 retains the application's original TCP/IP address and Port configuration data, in order to transmit and receive the data.) For widely used applications, configuring the application settings would be an automated installation process. In most cases, modifications or enhancements by the application vendors should not be required. [0055] As denoted in FIG. 1, the configuration for the application 100 is changed to use the "loopback" address 102, and TA will then communicate with the application 100 as though TA were the intended destination. TA 103 will examine and modify the data as necessary, and will forward the modified (e.g. secured) data to the intended destination through connection 106. In the other direction, TA 103 will receive data for the application 100 from connection 106, examine the data and unsecure it when necessary, and forward it to the application 100 through connection 102. Thus TA 103 allows the application 100 to be secure in transmitting and receiving its data without modification to the application's software. [0056] Sample Implementation: SMTP/POP3 E-Mail Client Interface [0057] [0057]FIG. 2 is a more specific example of implementing TA into an existing application environment. Again, the example shown is based on a device 101, e.g. a personal computer or PDA, with TCP/IP connectivity. The E-Mail client 100' in this example is reconfigured so that its SMTP/POP3 interfaces send and receive on the "loopback" TCP/IP address 127.0.0.2. Specifically, the SMTP target address saved (with many other parameters) in system configuration data file 108 (e.g. a Windows registry file) has been changed to 127.0.0.2, and the POP3 address has also been changed to 127.0.0.2. [0058] In this example the TA module 103' listens on 127.0.0.2 on the "Well known" port 25. When the SMTP interface 100A sends an E-Mail message and/or attachments, TA 103' intercepts the messages. [0059] The protocol level data is preferably be passed through intact, but the message content (indicated by the appropriate SMTP body tags etc.) can be transformed by the TA module 103'. That is, the TA module 103' preferably "parses" the SMTP transmission, to the limited extent needed to identify the message body and/or attachments, and then (depending on is programming) performs a data translation operation on these portions. The possibly-transformed body and attachment data, combined with the untransformed protocol data, is then sent along, through connection 106, to the SMTP server that was originally specified by the application. [0060] Correspondingly, the TA module 103' will listen on the reserved address (in this example 127.0.0.2 on Port 110) for the application to initiate a POP3 session. Thereafter TA 222 will monitor the session, and if secured data is encountered for this application/user, then the TA module 222 will unsecure the data. Otherwise the TA module 103' can simply pass the clear data through to the POP3 interface 100B. [0061] Both the SMTP and POP3 data securing and unsecuring processing are transparent to the application and virus scans implemented at the device. [0062] Installation of TA [0063] [0063]FIG. 13 gives an overview of the installation process (which, as noted, is preferably automatic.) In the presently preferred embodiment, TA (or its installation program) initially examines the windows registry 108 for e-mail client configurations. (The actual entry locations and data will vary depending on the versions of the E-Mail client and possibly the Windows operating system.) TA extracts the client configuration (steps 1310 and 1330) and saves the information in its own configuration file. [0064] TA (or the installation program) then updates the windows registry 108 with POP3 (step 1340) and SMTP (step 1320) configurations set to a reserved address, e.g. a loopback address 127.0.0.x. [0065] The TA module is then configured (step 1360) with logical relations which will cause it to load whatever translation algorithms are desired. (For example, hashing might be used for outbound messages to some addresses, or encryption for others. [0066] Once the TA module itself has been set up to launch automatically, the unit can be restarted (step 1390). [0067] TA then starts a listening function for POP3 and SMTP on the loopback address at the well known ports for POP3 and SMTP. [0068] When the e-mail client starts, it obtains the e-mail server configuration from the windows registry, and is not aware of the changes made by TA. [0069] When the e-mail client initiates a POP3 or SMTP request, it actually connects with TA on the same device. [0070] TA then initiates the same type connection with the actual POP3 or SMTP server. [0071] TA then monitors the information, receiving from the e-mail client and forwarding to the server and visa versa. [0072] If e-mail is being sent (SMTP), then TA looks for the recipient information, both primary and carbon copies. If any recipients are in the list of registered secured recipients for the encryption technology implemented then TA will wait for the actual text and attachments and secure the information. If there are no secure recipients then TA simply continues to pass the information. [0073] If a POP3 session is initiated then TA simply checks the information to determine if it is in a secure format, and unsecures the information if necessary, before passing it to the e-mail client. If TA is not able to decrypt the information, e.g. because the recipient is not the authorized recipient, then the information is passed to the email client in its as-received format. [0074] When TA is uninstalled, the uninstallation program preferably resets the registry entries back to their original configuration. [0075] Preferably, TA performs a test for integrity at startup. (For example, a checksum derived from the updated registry entries can be stored where TA can read it and check it.) [0076] The same general interface should function for Lotus Notes and IMAP with minor changes for these protocols. [0077] The example refers to the windows registry, but the specific client application may use some other form for saving its configuration information, such as an ".ini" file, and in this case the minimal access to registry described above is merely performed on the appropriate .ini file or other location. [0078] Non-E-Mail Applications [0079] [0079]FIG. 3 shows a generic TCP/IP session with a non-email application 100", which can include but is not limited to FTP, VPN, HTTP, video conferencing and peer-to-peer applications. By configuring the application 100" to send and receive using the "loopback" addressing scheme, TA is able to secure an application's data without modification to the application's software. TA can secure all data or selected data based on configuration parameters. TA can be configured using its secured configuration manager to use a different TCP/IP port on the device or for the destination. [0080] TA's mechanics of operation in this configuration are similar to those of the e-mail configuration of FIG. 2. The application's configuration data is preferably altered so that its send routines 100A' use a non-routable address 102A (preferably a loopback address), and its receive routines 100B' use a non-routable address 102B (also preferably a loopback address). The translation agent 103" is set up to capture accesses to these reserved addresses, and to perform data translation operations on the content of the transmissions as described above. Note however that the retransmission functions performed by translation agent 103" can be slightly more complicated than those performed by email translation agent 103', since the ultimate target address is not necessarily static. Where the target address is unpredictable (as in http: or ftp: accesses), the TA 103" is preferably configured either to snoop and divert all communications, or else to access dynamic routing data from inside the application 100". [0081] Secure Communication to Interdicting Server [0082] [0082]FIG. 4 shows a sample implementation in a client-server environment whereby the Server requires the data to be unsecured upon arrival. In this example an application 410, running on a physical device 101A (e.g. a workstation), is backed up by a local TA 420A which secures some or all of the communications over connection 106 (e.g. a LAN or WAN routing). A corresponding server-side TA 420S provides a complementary data translation interface between channel 106S and a server 430. An example of this environment could be organization with a central E-Mail server where the client 410 secures all data to the server (in this case E-Mail messages and attachments), and the E-Mail server 430 unsecures the data to perform a Server level virus scan. [0083] The reverse process can also be employed, where the client 410 only receives data that has been secured by the Server even when the originator did not have the capability. An example of this is shown in FIG. 7, where an application 710 on a remote device 101C can communicate with the application 410, but all communication must be routed through client-server channel 106S which is protected by TA modules 420A and 420S. Thus in this example the server 430 can be programmed (for example) to perform firewall and gateway functions needed for interface to the outside world. [0084] [0084]FIG. 8 shows a different implementation, where client-server communications over local channel 106L are not necessarily mediated by TA modules, but communications which must pass over a more exposed channel 106W are secured by TA modules 420A and 420S. Note that this diagram is very similar to FIG. 4, except that the channel assignments are different; in the embodiment of FIG. 8 the local network is assumed to be protected by (e.g.) physical security precautions, and the problem addressed is that of providing secure communications with remote workstations. [0085] Peer-to-Peer Implementations [0086] [0086]FIG. 6 shows an example where data transmission can also be secured in a peer-to-peer environment. In this example processes 610A and 610B, running on two different physical devices 10A and 101B, have their communications mediated by the complementary operations of respective translation agents 103. Note again that the physical devices 101 do not have to be computers, but can be, for example, components of a computing system. Thus, for example, in a large computing system which uses an array of asynchronous processors to form a "compute farm," or an array of storage devices to form a "server farm," the TA modules can be added in to modify peer-to-peer communications. Note, however, that this modification is not as attractive for applications where latency in communications is a action. [0087] If TA is used to secure information within a device then the same loop interface exists, but TA loops the transmission back to the application after having taken the appropriate action (encrypt or decrypt). [0088] The arrows on the document are meant to show flow of the information. In actuality the information is normally a two way exchange over the one connection between the software. In other words the application probably sends and receives over one TCP/IP connection for one function and likewise TA sends and receives over the one connection. [0089] Adaptation to Mobile Systems [0090] [0090]FIG. 11 is a sample of the devices that can achieve secure communication, using the TA, through the Internet (or other large network). This diagram is not an exhaustive list at all, but does give some idea of the range of applications of TA technology. The illustrated devices, which can be connected through the Internet or some other TCP/IP or analogous network, include without limitation: Windows.TM. computers; Unix/Linux computers; MacIntosh.TM. computers; PDA devices; digital cell phones; other digital devices; mainframe computers; servers; videoconferencing stations; Windows-CE.TM. devices; minicomputers; IP telephones; Bluetooth devices; satellites; digital cameras; and laptop or notebook computers. [0091] A particularly attractive contemplated use of the disclosed inventions is in handheld mobile internet devices. Such devices (such as the Blackberry, or other SIM-enabled PDAs) are increasingly coming to include substantial memory and processing power, and are often designed for easy installation of software applications and accessories. It is contemplated that the modular add-on capability of a "translation agent" as described above can be particularly advantageous for updating such systems to include user-selected translation operations as described above. [0092] The Blackberry, for example, uses a Java.TM. operating system, and therefore the above functionality implies a slight modification to the "JVM" (the "Java Virtual Machine," which any Java-capable computer must be able to emulate). That is, Java instructions are assumed to be executed by the Java virtual machine, and any particular computer must be equipped with software drivers to implement the JVM. Typically Java midlets sit on the Blackberry to perform encryption and related functions. [0093] XDA is a competitor to Blackberry, which uses Windows CE, and the disclosed inventions can be similarly adapted to the XDA. [0094] Other implementations (in Java, embedded Linux, PalmOS, or other system software) can similarly be ported to Epoc or other machines, including but not limited to any "3G" or "2.5G" phone. [0095] In the special case of routing e-mail into PDAs (or telephones or other mobile information appliances), the TA can also be set up for formatting functions, e.g. for selective stripping of attachments and/or images. This function is a normal part of low-bandwidth wide-area wireless network communication, but the ability to include it in the TA, where it is performed transparently to the devices and applications involved, provides a new capability. [0096] Two-Translation-Agent Methods [0097] In one class of embodiments, communications between two Translation Agents (or more precisely, between two TA-mediated devices) can be structured to introduce modifications (e.g. for security) even when using protocols (such as FTP) which are inherently unsecure. Thus TA's capabilities are not limited to securing data in transit. TA's in combination can also implement or enhance security and authentication functions, within the communication architecture, which are virtually impossible to achieve without changes in basic internet standards and/or massive changes in software and servers. [0098] In such embodiments, the TA's which jointly control a communication channel can be programmed to jointly introduce non-standard enhancements to standard protocols. [0099] According to various disclosed embodiments of the present invention, there is provided: A system, comprising: a communications interface module which transmits data over a communication channel according to an addressing protocol which includes one or more reserved addresses which are not freely available for external communication, and also includes non-reserved addresses; at least one active program which sends first communications into said channel through said interface module, using non-reserved addresses, and which also sends second communications to said interface module using ones of said reserved addresses; and an additional module which a) detects ones of said second communications, b) modifies data in ones of said second communications, and c) transmits results of said operation b). [0100] According to various disclosed embodiments of the present invention, there is provided: A system, comprising: a communications interface module which transmits data over a communication channel according to an addressing protocol which includes non-reserved addresses and also one or more reserved loopback addresses which are not freely available for external communication, and which echoes back data addressed to one of said reserved addresses; at least one active program which sends first communications into said channel through said interface module, using non-reserved addresses, and which also sends second communications through said interface module using ones of said reserved loopback addresses; and an additional module which a) detects ones of said second communications, b) modifies data in ones of said second communications, and c) transmits results of said operation b). [0101] According to various disclosed embodiments of the present invention, there A system, comprising: a communications interface module which transmits data over a communication channel according to an addressing protocol which includes one or more reserved addresses which are not freely available for external communication, and also includes non-reserved addresses; at least one active program which sends first communications into said channel through said interface module, using non-reserved addresses, and which also sends second communications through said interface module using ones of said reserved addresses; and an additional module which a) detects ones of said second communications, b) modifies data content portions thereof but not protocol-related header portions thereof, and c) transmits results of said operation b). [0102] According to various disclosed embodiments of the present invention, there is provided: A system, comprising: a communications interface module which transmits data over a communication channel according to an addressing protocol which includes one or more reserved addresses which are not freely available for external communication, and also includes non-reserved addresses; at least one active program which sends first communications into said channel through said interface module, using non-reserved addresses, and which also sends second communications through said interface module using ones of said reserved addresses; and an additional module which a) detects ones of said second communications, b) modifies data in ones of said second communications, and c) transmits results of said operation b); and which also d) intercepts and modifies at least some incoming transmissions directed to said active program. [0103] According to various disclosed embodiments of the present invention, there is provided: A system, comprising: a communications interface module which transmits data over a communication channel according to an addressing protocol which includes one or more reserved addresses which are not freely available for external communication, and also includes non-reserved addresses; at least one active program which sends first communications into said channel through said interface module, using non-reserved addresses, and which also sends second communications through said interface module using ones of said reserved addresses; and an additional module which a) detects ones of said second communications, b) selectively modifies data in only some ones of said second communications, and c) transmits results of said operation b). [0104] According to various disclosed embodiments of the present invention, there is provided: A system, comprising: a communications interface module which transmits data over a communication channel; at least one active program which sends communications into said channel through said interface module; and an additional software module which a) monitors at least some ones of said communications, b) selectively modifies data in only some ones of said second communications, and c) transmits results of said operation b) through said interface module. [0105] According to various disclosed embodiments of the present invention, there is provided: A computer, comprising: a network interface module which transmits and receives data over a communication channel according to an addressing protocol which includes non-reserved addresses and also one or more reserved addresses which are not freely available for external communication; at least one active program, running on a CPU of said computer, which sends first communications into said channel through said interface module, using non-reserved addresses, and which also sends second communications through said interface module using ones of said reserved addresses; and an additional module, running on a CPU of said computer, which a) detects ones of said second communications, b) modifies data in ones of said second communications, and c) transmits results of said operation b). [0106] According to various disclosed embodiments of the present invention, there is provided: A macro-system, comprising: multiple complex systems following respective instruction streams; and at least one network linking said multiple complex systems; wherein multiple ones of said complex systems each comprise: a communications interface module which transmits data over said network according to an addressing protocol which includes non-reserved addresses and also one or more reserved addresses which are not freely available for external communication; at least one active program which sends first communications into said network through said interface module, using non-reserved addresses, and which also sends second communications through said interface module using ones of said reserved addresses; and an additional module which a) detects ones of said second communications, b) processes data in ones of said second communications, and c) transmits results of said operation b). [0107] According to various disclosed embodiments of the present invention, there is provided: A modular expandable software architecture, comprising: an application program which performs at least one class of interface operations by looking up, in a configuration file, a network address which is used for said interface operations; said configuration file containing a reserved address, which does not correspond to any externally routable address, in place of the network address expected by said application program; and a functional module which, when said application program attempts to send data to said reserved address, performs data translation on said data, and retransmits said data, as modified by said data translation, to an externally routable network address. [0108] According to various disclosed embodiments of the present invention, there is provided: A method, comprising the steps of: (a.) from an application program, sending out a packet, which is intended for a real destination, to a first reserved address which cannot correspond to any real destination; and (b. ) in a translation program, looking up a second address, corresponding to said real destination in a table in memory, and transforming the data of said packet, and rerouting said packet thereafter to said second address. [0109] According to various disclosed embodiments of the present invention, there is provided: A software structure in a storage medium, comprising instructions which, when activated by at least one processor, will direct the processor to perform operations to implement the method of claim 42. [0110] According to various disclosed embodiments of the present invention, there is provided: A method for adding a data conversion function to a third-party software program, comprising the steps of: in a configuration file, replacing at least one target address with a respective non-routable address; and adding a functional module which, when the third-party program attempts to send a packet to said reserved address, performs data translation on the content of the packet according to stored algorithms, and retransmits the content, as modified by said data translation, to an externally routable address. [0111] According to various disclosed embodiments of the present invention, there is provided: A method for adding data translation functions to a third-party e-mail program, comprising the steps of: in a configuration file, substituting a reserved address, which does not correspond to any externally routable address, for the correct e-mail upload address; and adding an functional module which, when the e-mail program attempts to send a packet to said reserved address, performs data translation on the content of the packet according to stored algorithms, and retransmits the content to the correct e-mail upload address. [0112] Definitions: [0113] Following are short definitions of the usual meanings of some of the technical terms which are used in the present application. (However, those of ordinary skill will recognize whether the context requires a different meaning.) Additional definitions can be found in the standard technical dictionaries and journals. [0114] The term "network" is used very generally in the present application, to include wireless as well as wired, optical as well as electrical, local area networks (LANs) and wide area networks (WANs), the Internet, and closed networks (such as that used by the banking system). [0115] "TCP/IP" is a network addressing protocol dating back to ARPANET, and now in very wide use. The "IP" addresses used by TCP/IP have the format of four numbers, each less than 2{circumflex over ( )}8, separated by periods. (Each of these numbers corresponds to two bytes of data, i.e. 8 bits.) [0116] A "packet" is a block of data, in a defined format, which can be routed independently of other packets; standard rules permit a stream of data to be converted to or from packets. [0117] A "port" is a local destination designator: TCP/IP packets include a two-byte port designation in addition to the eight bytes of IP address. Of the 64K possible port designations, a few (mostly within the first 1K) have standard assignments see http://www.faqs.org/ftp/rfc/rfc1340.txt, which is hereby incorporated by reference. For example, port 110 is normally reserved for POP3, 25 for SMTP, 80 for HTTP, and 23 for telnet. (One of these standard assignments is specifically referred to, confusingly, as the "well-known" port.) [0118] A "reserved address" is an address which cannot be routed over the Internet. In TCP/IP these include the loopback addresses discussed above, and a few other blocks of "non-routable" or "unresolvable" addresses (all 10.x.x.x addresses; all 90.x.x.x addresses; 172.16.x.x through 172.31.x.x; and 192.168.x.x). [0119] "Virtual private networks" (VPNs) are network-type communication schemes which embed limited-access constraints within communications over the Internet (or other open or less-secure network). Some common examples of these are referred to as extranets. [0120] A "hub" is a hardware device which echoes packets from one physical network connection into others. [0121] A "router" is a programmable hub which is normally used to echo packets from a local network into the Internet, and vice versa. A router can be programmed, for example, for address-dependent transmission, address translation, port-mapping, and "firewall" and other such higher-level functions. [0122] A "firewall" is a special network interface function which performs authorization checking, refuses unauthorized connections, and may also do address translation, port-mapping packet filtering, and other high-level functions. Firewall functions are commonly integrated with router hardware, but can be implemented separately. [0123] "Packet filtering" is content-dependent routing. Any router performs address-dependent routing, but filtering implies that the data in the packet is analyzed in some fashion to affect routing. (For example, packets in which a virus signature is found may be discarded.) [0124] "Packet sniffing" is an operation which extracts the contents of packets and (possibly depending on contents, addresses or both) saves them elsewhere. [0125] SMTP (Simple Mail Transport Protocol) and POP3 (Post Office Protocol 3) are commonly-used e-mail protocols (one for outgoing, one for incoming). SMTP implementations in which extra functions have been added are sometimes referred to as "ESMTP." [0126] GSM is a cell phone standard--see e. g. http://www.iec.org/online/t- utorials/gsm/ and links therein, all of which are hereby incorporated by reference. "SMS" (standard Short Message Protocol) and "GPRS" (Global Packetized Radio Service) are also defined by the GSM standard. [0127] "JVM" is the "Java Virtual Machine" which any Java-capable computer must be able to emulated. That is, Java instructions are assumed to be executed by the Java virtual machine, and any particular computer must be equipped with software drivers to implement the JVM. [0128] Modifications and Variations [0129] As will be recognized by those skilled in the art, the innovative concepts described in the present application can be modified and varied over a tremendous range of applications, and accordingly the scope of patented subject matter is not limited by any of the specific exemplary teachings given. [0130] Translation Agent modules are capable of being daisy chained for special functions. In a circumstance such as an environment with multiple encryption technologies, a primary TA would receive and interrogate the data. If it found data it could recognize as another encryption technology or a recipient who is configured for receiving in another supported encryption technology, then TA could open a connection using a loopback address and predetermined port and pass then information to that TA processor. The secondary TA would not necessarily know that the information was routed from a primary TA rather than any other TCP/IP stream. [0131] While the invention is particularly advantageous with TCP/IP address protocols, it can also be used with IPX, NetBEUI, NetBIOS, SMB (used for file and print sharing in MS Network) or other protocols, as long as there is a reserved address which can be used for internal communications (intra-chassis or intra-system). [0132] As noted, the disclosed inventions are particularly useful for adding capability to third-party application programs. Some of the programs which are expected to benefit particularly from this are Notes, Eudora, Outlook, Outlook Express, Groupwise, but of course other commercial software packages can also benefit. [0133] An important security benefit is that, in many embodiments, the data translation into a secure format occurs totally inside the system box. This provides an interesting synergy with computers (or other devices) where the CPU itself controls opening of the box, by a "hoodlock" mechanism. (See e.g. U.S. Pat. No. 6,307,738, which is hereby incorporated by reference.) In such cases the TA's resistance to hacking combines advantageously with the hoodlock's protection against physical intrusion. [0134] In an alternative and less preferred class of embodiments, reserved addresses which are not loopback addresses can be used instead. In this case the TA can merely snoop communications, and grab packets which are directed to the particular reserved address(es) it recognizes. [0135] In another alternative and less preferred class of embodiments, addresses can used for TA interception which are not defined as "reserved" within the protocol. In this case the addresses assigned for TA interception must be ones which will not be the target of any legitimate address generated by application software. For example, when Network Address Translation is being used, it is possible to define the rules so that some otherwise-permissible IP addresses should not appear at some points within the network topology. In this case such addresses can be used to define a "hidden call" to a TA routine at a gateway or router. Here too the TA can merely snoop communications, and grab packets which are directed to the particular reserved address(es) it recognizes. [0136] In another alternative and less preferable class of embodiments, the TA can be used in high-speed networks, such as are used in computation clusters or server farms. Here too the disclosed architecture provides a simple way of adding an overlaid structure into an existing network interface architecture. However, in this environment the TA module should of course have a throughput which is high enough not to impose a bottleneck into the communications channel. [0137] Note that multiple different functions can optionally be assigned to different reserved (loopback) addresses: e.g. FTP, locking functions (dongles), secure email, https:, VPN (of whatever configuration) and others can each be assigned to its own loopback address. This allows multiple different routines to be called merely by specifying an appropriate TCP/IP reserved address, or alternatively different routines can each snoop data content of messages sent to some (but not all) of the reserved addresses. [0138] In one alternative class of embodiments, the TA module can include biometric identification functions. In such embodiments the processing performed by the TA module can be made dependent on various authentication components, such as voice recognition, face recognition, input from a portable electronic key, manual entry of a password or PIN, etc. The sensors and interfaces needed for fingerprint or retinal identification are not currently part of a normal personal computer, and the input for facial recognition is not on all computers, so a hardware security module which implements securitization with the TA interface can include dedicated sensor input connections, or even dedicated sensors. For added security these authentications can be combined with required GPS or time relations. [0139] The present application refers to the "TA module" where it is not necessary to specify whether the described functions are implemented in hardware or in software (or both). There are advantages to be gained in either case; an implementation with separate hardware has the potential to be more secure, but is more cumbersome to install. [0140] The disclosed inventions are believed to be particularly advantageous for wireless networks, which are inherently insecure. (Where the intended RF or IR interfaces have omnidirectional antennas, an eavesdropper's the antenna gain is a potential extra margin which can make the insecure area much larger than the useful area.) For similar reasons, the disclosed inventions can be particularly useful for WANs, where extensive signal routing outside the premises may be necessary. [0141] Typically the data sent out onto a network will have originated in a CPU, but in the present application this term is to be construed broadly to cover anything with computing capacity--e.g. a gate array, microcontroller, mainframe, etc. [0142] In one alternative embodiment the TA module can include dedicated routines and/or hardware for video and graphics decompression and buffering, to facilitate handling of streaming video. [0143] Where the disclosed TA is used with a multiprocessor computer, the CPU which is sending communications requests may not be the same one executing translation routines. [0144] References to digital data do not preclude later adaptation of the disclosed innovative teachings to analog or multi-bit data. [0145] One contemplated class of alternatives requires the router/firewall to have packet filtering capability. In this case the router can be programmed so that NO packets go out unless they include (or are preceded by) a signature from the TA. Where this degree of firewall blockade is available, it is not necessary to divert packet addresses coming out of the application; instead the TA can merely snoop outgoing traffic, and retransmit with authentication only packets of translated data, and packets which do not need to be translated. [0146] Additional general background, which helps to show the knowledge of those skilled in the art regarding the system context, and of variations and options for implementations, may be found in the following publications, all of which are hereby incorporated by reference: Mark Nelson, "The Data Compression Book" (2.ed.) (ISBN 1558514341); Gilbert Held, "Personal Computer File Compression" (ISBN 0442017731); Arturo Trujillo, "Translation Machines: Techniques for Machine (ISBN 1852330570); Tim Kientzle, "Internet File Formats" (ISBN 188357756X); Gunter Born, "The File Formats Handbook" (ISBN 1850321175); Bob Quinn and Dave Shute, "Windows Sockets Network Programming" (ISBN 0201633728); Peter Loshin, "Big Book of World Wide Web RFCs" (ISBN 0124558410); Ralph Droms, "DHCP (Dynamic Host Configuration Protocol)" (ISBN 1578701376); and Eric Hall, "Internet Core Protocols--The Definitive Guide" (ISBN 1565925726). [0147] None of the description in the present application should be read as implying that any particular element, step, or function is an essential element which must be included in the claim scope: THE SCOPE OF PATENTED SUBJECT MATTER IS DEFINED ONLY BY THE ALLOWED CLAIMS. Moreover, none of these claims are intended to invoke paragraph six of 35 USC section 112 unless the exact words "means for" are followed by a participle. Moreover, the claims filed with this application are intended to be as comprehensive as possible: EVERY novel and nonobvious disclosed invention is intended to be covered, and NO subject matter is being intentionally abandoned, disclaimed, or dedicated.

Abstract of the Disclosure An architecture in which data outputs from an application program into a communication interface are diverted, by changing their address to a reserved address, and then are processed further by an added program which is invisible to the application program.

FIELD OF THE INVENTION [0001] The present invention relates to a liposome having a sugar chain bonded to its membrane surface, preferably through a linker protein, and having excellent qualities in intestinal absorption, and to a liposome product comprising a drug or a gene encapsulated in the sugar-modified liposome. The liposome product may be used in preparations comprising medicinal drugs, cosmetics and other various products in the medical/pharmaceutical fields, and it is particularly useful in a therapeutic drug delivery system that specifically targets selected cells or tissues, such as cancer cells, and in the delivery of drugs or genes locally to a selected region, and in a diagnostic cell/tissue sensing probe. BACKGROUND OF THE INVENTION [0002] The realization of a “drug delivery system (DDS) for delivering drugs or genes intentionally and intensively to cancer cells or target tissues” has been set as one of the specific goals of the U.S. National Nanotechnology Initiative (NNI). The Nanotechnology/Materials Strategy of the Council for Science and Technology Policy in Japan also focuses research on “Medical micro systems/materials, Nanobiology for utilizing and controlling biological mechanisms,” and one of the five year R & D targets is “Establishment of basic seeds in health/life-lengthening technologies such as biodynamic materials and pinpoint treatments.” However, even in view of these goals the incidence and morbidity of cancers become higher year after year, along with a progressive aging of the population, and a serious need for the development of a targeting DDS material which is a novel treatment material exists. [0003] Targeting DDS nano-structured materials for other diseases also come under the spotlight because they have no side effects, and their market size of over 10 trillion yen is anticipated in the near future. Further, it is expected that these materials will be utilized in medical diagnosis as well as medical treatments. [0004] The therapeutic effect of a drug will be achieved only if the drug reaches a specific target region and acts thereupon. If the drug reaches a non-target region, undesirable side effects may result. Thus, the development of a drug delivery system that allows drugs to be used effectively and safely is also desired. In a drug delivery system, the targeting DDS can be defined as a concept of delivering a drug to a “necessary region in a body,” in a “necessary amount” and for a “necessary time-period.” A liposome is a noteworthy particulate carrier regarded as a representative material for a targeting DDS. While a passive targeting method based on modification of lipid type, composition ratio, size, or surface charge of liposomes has been developed to impart a targeting function to this particle, this method is still insufficient and required to be improved in many respects. [0005] An active targeting method has also been researched in an attempt to achieve a sophisticated targeting function. While the active targeting method referred to as a “missile drug” is conceptually ideal, it has not been accomplished in Japan and abroad, and future developments are expected. This method is designed to provide ligands bonded to the membrane surface of a liposome that will be specifically recognized and bound by a receptor residing on the cell-membrane surface of a target tissue, thereby achieving active targeting. The cell-membrane surface receptor ligands include antigens, antibodies, peptides, glycolipids, and glycoproteins. [0006] It is revealing that the sugar chain of glycolipids and glycoproteins bears an important role as an information molecules in various communications between cells, such as in the creation or morphogenesis of tissues, in the proliferation or differentiation of cells, in the biophylaxis or fecundation mechanism, and in the creation and metastasis of cancers. [0007] Further, research on various types of lectins (sugar-recognizing protein) such as selectin, siglec and galectin, which serve as receptors on cell-membrane surfaces of target tissues, has been proposed to serve as receptors for sugar chains having different molecular structures that may be used as noteworthy new DDS ligands (Yamazaki, N., Kojima, S., Bovin, N. V., Andre, S., Gabius, S. and H. -J. Gabius. Adv. Drug Delivery Rev. 43:225-244 (2000); Yamazaki, N., Jigami, Y., Gabius, H. -J., and S. Kojima. Trends in Glycoscience and Glycotechnology 13:319-329 (2001)). [0008] Liposomes having ligands bonded to their external membrane surface have been actively researched in order to provide a DDS material for delivering drugs or genes selectively to a target region, such as cancer. While these liposomes bind to target cells in vitro, most of them do not exhibit adequate targeting to intended target cells or tissues in vivo (Forssen, E. and M. Willis. Adv. Drug Delivery Rev. 29:249-271 (1998); Takahashi, T. and M. Hashida. Today's DDS/Drug Delivery System, Iyaku Journal Co., Ltd. (Osaka, Japan), 159-167 (1999)). While some research has been conducted on liposomes incorporating glycolipids having sugar chains, for use as a DDS material, these liposomes were evaluated only in vitro, and little progress has been reported for similar research on liposomes incorporating glycoproteins having sugar chains (DeFrees, S. A., Phillips, L., Guo, L. and S. Zalipsky. J. Am. Chem. Soc. 118:6101-6104 (1996); Spevak, W., Foxall, C., Charych, D. H., Dasqupta, F. and J. O. Nagy. J. Med. Chem. 39:1918-1020 (1996); Stahn, R., Schafer, H., Kernchen, F. and J. Schreiber. Glycobiology 8:311-319 (1998); Yamazaki, N., Jigami, Y., Gabius, H. -J., and S. Kojima. Trends in Glycoscience and Glycotechnology 13:319-329 (2001)). As above, systematic research into liposomes having a wide variety of sugar chains, on the glycolipids or glycoproteins bonded to the liposomes, including preparative methods and in vivo analyses thereof, is pending and represents an important challenge to be progressed in future. [0009] Further, in research on new types of DDS materials, it is an important challenge to develop a DDS material capable of being orally administered in the easiest and cheapest way. For example, when a peptide medicine is orally administered, it is subject to enzymolysis and may be only partially absorbed in the intestine due to its water solubility, high molecular weight, and low permeability in the mucosa of small intestine. As an alternative, a ligand-bonded liposome is getting attention as a potential DDS material for delivering high molecular-weight medicines or genes into the blood stream through the intestine (Lehr, C.-M. J. Controlled Release 65:19-29 (2000)). However, results from research into an intestinal absorption-controlled liposome, using a sugar chain as the ligand, have not been reported. SUMMARY OF THE INVENTION [0010] It is therefore an object of the present invention to provide a sugar-modified liposome that is specifically recognized and bound by selected lectins (sugar-recognizing proteins) residing on the surface of target cells and tissues, and having excellent qualities of absorption, particularly in the intestine. It is a further object of the present invention to provide a liposome product comprising a drug or gene encapsulated by a sugar-modified liposome that is recognized by cells or tissues in vivo, and that can specifically deliver drugs or genes to target cells or tissues. [0011] In order to meet the challenges mentioned above, various experimental tests and studies have been conducted on the properties of liposome surfaces, and on the sugar chains and linker proteins used to bond the sugar chains to the surface of liposomes. Through this research, it has been shown that the targeting performance of sugar-modified liposomes to particular target tissues can be controlled by the sugar chain structure. It has also been shown that the amount of liposome transferred to each target tissue can be increased by hydrating the liposome surface and/or the linker protein, resulting in more effective delivery of drugs or genes to each of the target cells or tissues. [0012] According to a first aspect of the present invention, there is provided a liposome having a sugar chain bonded to the liposome membrane surface. [0013] According to a second aspect of the present invention, there is provided a liposome having a sugar chain bonded to the liposome membrane surface, and further comprising tris (hydroxymethyl) aminomethane bonded to the liposome membrane surface. [0014] According to a third aspect of the present invention, there is provided a liposome having a sugar chain bonded to the liposome membrane surface through a linker protein. [0015] According to a fourth aspect of the present invention, there is provided a liposome having a sugar chain bonded to the liposome membrane surface through a linker protein, wherein both the liposome membrane surface and the linker protein are hydrophilized. [0016] According to a fifth aspect of the present invention, there is provided a liposome product comprising the sugar-modified liposome according to any one of the first to fourth aspects of the present invention, and a drug or gene encapsulated in the sugar-modified liposome. [0017] In each aspect of the present invention, the sugar chain is preferably selected from the group consisting of lactose disaccharide, 2′-fucosyllactose trisaccharide, difucosyllactose tetrasaccharide, 3-fucosyllactose trisaccharide, Lewis X trisaccharide, sialyl Lewis X tetrasaccharide, 3′-sialyllactosamine trisaccharide, and 6′-sialyllactosamine trisaccharide. [0018] In each aspect of the present invention, preferably an adjusted amount of the sugar chain is bonded to the membrane surface of the liposome. [0019] In each relevant aspect of the present invention, preferably the surface of the liposome and/or the linker protein is hydrophilized. Preferably, the hydrophilization is performed by using tris (hydroxymethyl) aminomethane. [0020] In each relevant aspect of the present invention, the linker protein is preferably human serum albumin or bovine serum albumin. BRIEF DESCRIPTION OF THE DRAWINGS [0021] [0021]FIG. 1 is a schematic diagram of a liposome modified by lactose disaccharide. [0022] [0022]FIG. 2 is a schematic diagram of a liposome modified by 2′-fucosyllactose trisaccharide. [0023] [0023]FIG. 3 is a schematic diagram of a liposome modified by difucosyllactose tetrasaccharide. [0024] [0024]FIG. 4 is a schematic diagram of a liposome modified by 3-fucosyllactose trisaccharide. [0025] [0025]FIG. 5 is a schematic diagram of a liposome modified by Lewis X trisaccharide. [0026] [0026]FIG. 6 is a schematic diagram of a liposome modified by sialyl Lewis X tetrasaccharide. [0027] [0027]FIG. 7 is a schematic diagram of a liposome modified by 3′-sialyllactosamine trisaccharide. [0028] [0028]FIG. 8 is a schematic diagram of a liposome modified by 6′-sialyllactosamine trisaccharide. [0029] [0029]FIG. 9 is a schematic diagram of a liposome modified by tris (hydroxymethyl) aminomethane, as a comparative sample. [0030] [0030]FIG. 10 is a diagram showing respective distribution rates in blood of 4 types of liposome complexes (including a TRIS comparative example), differing in the amount of lactose disaccharide bonded thereto, after 10 minutes from their intestinal administration. [0031] [0031]FIG. 11 is a diagram showing respective distribution rates in blood of 4 types of liposome complexes (including a TRIS comparative example), differing in the amount of 2′-fucosyllactose trisaccharide bonded thereto, after 10 minutes from their intestinal administration. [0032] [0032]FIG. 12 is a diagram showing respective distribution rates in blood of 4 types of liposome complexes (including a TRIS comparative example), differing in the amount of difucosyllactose tetrasaccharide bonded thereto, after 10 minutes from their intestinal administration. [0033] [0033]FIG. 13 is a diagram showing respective distribution rates in blood of 4 types of liposome complexes (including a TRIS comparative example), differing in the amount of 3-fucosyllactose trisaccharide bonded thereto, after 10 minutes from their intestinal administration. [0034] [0034]FIG. 14 is a diagram showing respective distribution rates in blood of 5 types of liposome (including a TRIS comparative example) complexes after 60 minutes from their intravenous administration. [0035] [0035]FIG. 15 is a diagram showing respective distribution rates in liver of 5 types of liposome complexes (including a TRIS comparative example) after 60 minutes from their intravenous administration. [0036] [0036]FIG. 16 is a diagram showing respective distribution rates in spleen of 5 types of liposome complexes (including a TRIS comparative example) after 60 minutes from their intravenous administration. [0037] [0037]FIG. 17 is a diagram showing respective distribution rates in lung of 5 types of liposome complexes (including a TRIS comparative example) after 60 minutes from their intravenous administration. [0038] [0038]FIG. 18 is a diagram showing respective distribution rates in brain of 5 types of liposome complexes (including a TRIS comparative example) after 60 minutes from their intravenous administration. [0039] [0039]FIG. 19 is a diagram showing respective distribution rates in cancer tissues of 5 types of liposome complexes (including a TRIS comparative example) after 60 minutes from their intravenous administration. [0040] [0040]FIG. 20 is a diagram showing respective distribution rates in inflammatory tissues of 5 types of liposome complexes (including a TRIS comparative example) after 60 minutes from their intravenous administrations. [0041] [0041]FIG. 21 is a diagram showing respective distribution rates in lymph node of 5 types of liposome complexes (including a TRIS comparative example) after 60 minutes from their intravenous administration. DETAILED DESCRIPTION OF THE INVENTION [0042] The present invention will now be described in detail. [0043] A liposome generally means a closed vesicle consisting of a lipid layer formed as a membrane-like aggregation, and an inner water layer. [0044] As shown in FIGS. 1 to 8 , a liposome of the present invention includes a liposome with a sugar chain covalently bonded to its membrane surface or its lipid layer through a linker protein such as human serum albumin. While only a single sugar chain-linker protein set, bonded to the liposome, is illustrated in FIGS. 1 to 8 , these figures (including FIG. 9) are schematic diagrams, and a number of sugar chain-linker protein sets are actually bonded to the liposome surface. [0045] The liposomes of the present invention are modified by a sugar chain. Preferred examples of the sugar chains include lactose disaccharide (Gal. beta. 1-4 Glc) shown in FIG. 1, 2′-fucosyllactose trisaccharide (Fuc. alpha.1-2 Gal. beta. 1-4 Glc) shown in FIG. 2, difucosyllactose tetrasaccharide (Fuc. alpha. 1-2 Gal. beta. 1-4 (Fuc. alpha. 1-3) Glc) shown in FIG. 3, 3-fucosyllactose trisaccharide (Gal. beta. 1-4(Fuc. alpha. 1-3) Glc) shown in FIG. 4, Lewis X trisaccharide (Gal. beta. 1-4 (Fuc. alpha. 1-3) GlcNAc) shown in FIG. 5, sialyl Lewis X tetrasaccharide (Neu5Ac. alpha. 2-3 Gal. beta. 1-4 (Fuc. alpha. 1-3) GlcNAc) shown in FIG. 6, 3′-sialyllactosamine trisaccharide (Neu5Ac. alpha. 2-3 Gal. beta. 1-4GlcNAc) shown in FIG. 7, and 6′-sialyllactosamine trisaccharide (Neu5Ac. alpha. 2-6 Gal. beta. 1-4 GlcNAc) shown in FIG. 8. [0046] In the present invention, it is preferred to bond the sugar chain to the membrane surface of the liposome through a linker protein. Such liposome structures are shown in FIGS. 1 to 8 , together with the chemical structures of the sugar chain. [0047] The linker protein may be an animal serum albumin, such as human serum albumin (HSA) or bovine serum albumin (BSA). In particular, it has been verified through experimental tests using mice that a liposome complex using human serum albumin is taken into target tissues in a greater amount than a liposome complex using a different linker protein. [0048] The lipid constituting the liposomes of the present invention includes phosphatidylcholines, phosphatidylethanolamines, phosphatidic acids, gangliosides, glycolipids, phosphatidylglycerols, and cholesterol. The phosphatidylcholines preferably include dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine, and distearoylphosphatidylcholine. The phosphatidylethanolamines preferably include dimyristoylphosphatidylethanolamine, dipalmitoylphosphatidylethanolamine, and distearoylphosphatidylethanolamine. The phosphatidic acids preferably include dimyristoylphosphatidic acid, dipalmitoylphosphatidic acid, distearoylphosphatidic acid, and dicetylphosphoric acid. The gangliosides preferably include ganglioside GM1, ganglioside GD1a, and ganglioside GT1b. The glycolipids preferably include galactosylceramide, glucosylceramide, lactosylceramide, phosphatide, and globoside. The phosphatidylglycerols preferably include dimyristoylphosphatidylglycerol, dipalmitoylphosphatidylglycerol, and distearoylphosphatidylglycerol. [0049] While a regular liposome may be used in the invention, it is preferable to hydrophilize the surface of the liposome. [0050] The liposome itself can be produced through any conventional method including a thin film method, a reverse phase evaporation method, an ethanol injection method, and a dehydration-rehydration method. [0051] The particle size of the liposome can be controlled through an ultrasonic radiation method, an extrusion method, a French press method, a homogenization method or any other suitable conventional method. [0052] A specific method of producing the liposome itself of the present invention will be described below. For example, a mixed micelle is first prepared by mixing a compounded lipid consisting of phosphatidylcholines, cholesterol, phosphatidylethanolamines, phosphatidic acids, and gangliosides or glycolipids or phosphatidylglycerols, with sodium cholic acid serving as a surfactant. Particularly, the phosphatidylethanolamines are essentially compounded to provide a hydrophilic reaction site, and the composition of gangliosides or glycolipids or phosphatidylglycerols are essentially compounded to provide a bonding site for the linker protein. [0053] The obtained mixed micelle is subjected to ultrafiltration to prepare a liposome. Then, the membrane surface of the liposome is hydrophilized by applying a bivalent crosslinking reagent and tris (hydroxymethyl) aminomethane onto the lipid phosphatidylethanolamine of the membrane of the liposome. [0054] The liposome can be hydrophilized through a conventional method such as a method of producing a liposome by using phospholipids covalently bonded with polyethylene glycol, polyvinyl alcohol, maleic anhydride copolymer or the like (Japanese Patent Laid-Open Publication No. 2001-302686). However, in the present invention, it is particularly preferable to hydrophilize the liposome membrane surface by using tris (hydroxymethyl) aminomethane. [0055] The technique using tris (hydroxymethyl) aminomethane has some advantages superior to the conventional method of using polyethylene glycol or the like. For example, when a sugar chain is bonded onto a liposome and the molecular recognition function of the sugar chain is utilized for bringing about the targeting performance as in the present invention, the tris (hydroxymethyl) aminomethane is particularly preferable because it is a substance having a low molecular weight. More specifically, as compared to the conventional method using a substance having a high molecular weight such as polyethylene glycol, the tris (hydroxymethyl) aminomethane is less apt to become a three-dimensional obstacle to the sugar chain and to prevent the lectin (sugar-recognizing protein) on the membrane surface of target cells from recognizing the sugar-chain molecule. [0056] In addition, the liposome according to the present invention is excellent in terms of particle-size distribution, composition, and dispersing characteristics, as well as in long-term storage stability and in vivo stability, even after the above hydrophilization, and thereby is suitable for forming into and using as a liposome product. [0057] As an example of the process for forming of a liposome hydrophilized through the use of tris (hydroxymethyl) aminomethane, a bivalent reagent is added to a liposome solution. Exemplary bivalent reagents include bissulfosuccinimidylsuberate, disuccinimidylglutarate, dithiobissuccinimidylpropionate, disuccinimidylsuberate, 3,3′-dithiobissulfosuccinimidylpropionate, ethylene glycol bissuccinimidylsuccinate, or ethylene glycol bissulfosuccinimidylsuccinate. Exemplary lipids include dimyristoylphosphatidylethanolamine, dipalmitoylphosphatidylethanolamine, and distearoylphosphatidylethanolamine. Upon combination, a reaction between the bivalent reagent and the lipid occurs so as to bond the bivalent reagent to the lipid on the membrane of the liposome. Then, the tris (hydroxymethyl) aminomethane is reacted with the bivalent reagent to bond the tris (hydroxymethyl) aminomethane to the liposome surface. [0058] In the present invention, the sugar chain may be bonded to the liposome through a linker protein. The linker protein is first bonded to the liposome by first treating the liposome with an oxidant such as NaIO 4 , Pb(O 2 CCH 3 ) 4 , or NaBiO 3 to oxidize the gangliosides residing on the membrane surface of the liposome. The linker protein is then bonded to the gangliosides on the liposome membrane surface by a reductive amination reaction using a reagent such as NaBH 3 CN or NaBH 4 . [0059] Preferably, the linker protein is also hydrophilized by bonding a moiety having a hydroxy group to the linker protein. For example, tris (hydroxymethyl) aminomethane may be bonded to the linker protein on the liposome by using a bivalent reagent such as bissulfosuccinimidylsuberate, disuccinimidylglutarate, dithiobissuccinimidylpropionate, disuccinimidylsuberate, 3,3′-dithiobissulfosuccinimidylpropionate, ethylene glycol bissuccinimidylsuccinate, or ethylene glycol bissulfosuccinimidylsuccinate, as discussed above. [0060] One of the ends of a bivalent crosslinking reagent is bonded to the amino groups of the linker protein. Then, the reduction terminals of desired types of sugar chains are glycosylaminated to prepare a sugar-chain glycosylamine compound, and the amino groups of the obtained sugar chains are bonded to a part of the other unreacted ends of the bivalent crosslinking reagent bonded to the linker protein on the liposome. [0061] Then, the surface of the resulting linker protein which resides on the membrane surface of the liposome has the sugar chain bonded thereto and is hydrophilized by using the mostly remaining unreacted ends of the bivalent reagent to which no sugar chain is bonded. That is, a bonding reaction is caused between the unreacted ends of the bivalent reagent bonded to the linker protein on the liposome and tris (hydroxymethyl) aminomethane, so as to hydrophilize the liposome surface to obtain the liposome according to the present invention. [0062] The hydrophilization of the liposome surface and the linker protein provides enhanced mobility toward various tissues and enhanced sustainability in various tissues. This advantage is realized because the hydrophilized liposome surface and linker protein become hydrated by water molecules in vivo or in a blood vessel, which allows a portion of the liposome complex, other than the sugar chain, to function as if it is a layer of water which is not recognized by the various tissues. The liposome complex is thus not recognized by any tissues other than target tissues and only through the sugar chain is recognized by the lectin (sugar-recognizing protein) of the target tissues. [0063] As a next general step in the production of the sugar-modified liposomes of the present invention, the sugar chain is bonded to the linker protein on the liposome. For this purpose, the reduction terminal of the sugars constituting the sugar chain is, for example, glycosylaminated by using ammonium salts such as NH 4 HCO 3 or NH 2 COONH 4 , and then the linker protein bonded onto the liposome membrane surface is bonded to the above glycosylaminated sugars using a bivalent reagent such as bissulfosuccinimidylsuberate, disuccinimidylglutarate, dithiobissuccinimidylpropionate, disuccinimidylsuberate, 3,3′-dithiobissulfosuccinimidylpropionate, ethylene glycol bissuccinimidylsuccinate, or ethylene glycol bissulfosuccinimidylsuccinate to obtain the liposomes shown in FIGS. 1 - 8 . [0064] The sugar-modified liposomes of the present invention generally exhibit significantly high intestinal absorption. In addition, the intestinal absorption of the liposomes can be controlled by adjusting the density of the sugar chains bonded to the liposome, so that the liposome can more efficiently deliver drugs to target regions with reduced side effects. For example, FIGS. 10 to 13 show the results of studies performed to determine the rates of distribution (or intestinal absorption) of four different sugar-modified liposomes from intestine to blood, where the amount of sugar chain bonded to the respective liposomes is changed in three levels. [0065] In these experiments, the amount of sugar chain bonded to the respective liposomes is changed by bonding the sugar chain to the linker protein-bonded liposome at three density levels: (1) 50 μg, (2) 200 μg, and (3) 1 mg. As shown in the Figures, when lactose disaccharide is used as the sugar chain, the intestinal absorption is gradually lowered as the density of the sugar chain is increased. By contrast, when 2′-fucosyllactose trisaccharide or difucosyllactose tetrasaccharide is used as the sugar chain, the intestinal absorption is increased as the density of the sugar chain is increased. When 3-fucosyllactose trisaccharide is used as the sugar chain, the intestinal absorption is lowered and then increased as the density of the sugar chain is increased. [0066] These characteristics show that intestinal absorption is altered by the amount of sugar chain bonded to the liposome for each type of sugar chain. Thus, intestinal absorption can be controlled by appropriately selecting the amount and type of sugar chain bonded to the liposome. [0067] The results from additional experiments demonstrate that the type and amount of sugar chain bonded to the surface of the sugar-modified liposomes of the present invention can directly effect the targeting performance of the liposomes to particular target cells or tissues. The results of these experiments are shown in FIGS. 14 to 21 . [0068] For example, it is evident from the results that liposomes (LX, SLX, 3SLN, 6SLN) modified by four types of sugar chains: Lewis X trisaccharide, sialyl Lewis X tetrasaccaride, 3′-sialyllactosamine trisaccharide, and 6′-sialyllactosamine trisaccharide, generally have a high targeting performance to cancer tissues and inflammatory tissues (FIGS. 19 and 20). In particular, sialyl Lewis X tetrasaccaride modified liposomes (SLX) have a high targeting performance to liver, spleen, brain and lymph node (FIGS. 15, 16, 18 and 21 ), 3′-sialyllactosamine trisaccharide modified liposomes (3SLN) have a high targeting performance to blood, brain and cancer tissues (FIGS. 14, 18, and 19 ), and 6′-sialyllactosamine trisaccharide modified liposomes (6SLN) have a high targeting performance to blood and lung (FIG. 14 and 17 ). [0069] The liposome product obtained by encapsulating drugs or genes for therapeutic or diagnostic purposes, using the sugar-modified liposomes of the present invention, would also have a targeting performance selectively controlled by the amount and identity of the sugar chains bonded to the liposome. Thus, the liposome product of the present invention can be used to provide enhanced delivery of therapeutic drugs or diagnostic agents to target cells and tissues, as well as to suppress side effects by reducing the ability of drugs to be taken into non-target cells and tissues. [0070] Drugs, such as cancer drugs, or genes, such as those used in gene therapy, may be encapsulated in the sugar-modified liposomes of the present invention through any suitable conventional method including a method of forming the liposome by using a solution including the drugs or genes, and a lipid such as a phosphatidylcholines or phosphatidylethanolamines. [0071] Various examples of the present invention will be described below, but the invention is not limited thereto. EXAMPLE 1 Preparation of Liposomes [0072] Liposomes were prepared through an improved type of cholate dialysis based on a previously reported method (Yamazaki, N., Kodama, M. and H.-J. Gabius. Methods Enzymol. 242:56-65 (1994)). More specifically, 46.9 mg of sodium cholate was added to 45.6 mg of lipid mixture consisting of dipalmitoylphosphatidylcholine, cholesterol, dicetylphosphate, ganglioside and dipalmitoylphosphatidylethanolamine at a mole ratio of 35:40:5:15:5, respectively, and the lipid mixture was dissolved in 3 ml of chloroform/methanol solution. The solution was then evaporated, and the resulting deposit was dried in vacuo to obtain a lipid membrane. The obtained lipid membrane was suspended in 3 ml of a TAPS buffer solution (pH 8.4), and was subjected to a supersonic treatment to obtain a clear micelle suspension. Then, this micelle suspension was subjected to ultrafiltration by using a PM 10 membrane (Amicon Co., USA) and a PBS buffer solution (pH 7.2) to prepare 10 ml of a uniform liposome (average size of 100 nm). EXAMPLE 2 Hydrophilization of Lipid Membrane Surface of Liposomes [0073] 10 ml of the liposome solution prepared in Example 1 was subjected to ultrafiltration by using an XM 300 membrane (Amicon Co., USA) and a CBS buffer solution (pH 8.5) to adjust the pH of the solution to 8.5. Then, 10 mg of bis (sulfosuccinimidyl) suberate (BS3; Pierce Co., USA) crosslinking reagent was added to the liposome solution. The obtained solution was stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night to complete the reaction between the BS3 and the dipalmitoylphosphatidyletanolamine of the lipid on the liposome membrane. This liposome solution was then subjected to ultrafiltration by using an XM 300 membrane and a CBS buffer solution (pH 8.5). Then, 40 mg of tris (hydroxymethyl) aminomethane dissolved in 1 ml of CMS buffer solution (pH 8.5) was added to 10 ml of the liposome solution. The obtained solution was stirred at 25° C. for 2 hours, and stirred at 7° C. for one night to complete the reaction between the BS3 bonded to the lipid on the liposome membrane and the tris (hydroxymethyl) aminomethane. In this manner, the hydroxyl groups of the tris (hydroxymethyl) aminomethane were coordinated on the dipalmitoylphosphatidyletanolamine of the lipid on the liposome membrane to achieve the hydrophilization of the lipid membrane surface of the liposome. EXAMPLE 3 Bonding of Human Serum Albumin (HSA) to Membrane Surface of Liposomes [0074] Human serum albumin (HSA) was bonded to the membrane surface of the liposome through a coupling reaction method based on a previously reported method (Yamazaki, N., Kodama, M. and H. -J. Gabius. Methods Enzymol. 242:56-65 (1994)). More specifically, the reaction was carried out through a two-stage reaction method. That is, 43 mg of sodium metaperiodate dissolved in 1 ml of TAPS buffer solution (pH 8.4) was added to 10 ml of the liposome obtained in Example 2, and the obtained solution was stirred at room temperature for 2 hours to periodate-oxidize the ganglioside on the membrane surface of the liposome. Then, the solution was subjected to ultrafiltration by using an XM 300 membrane and a PBS buffer solution (pH 8.0) to obtain 10 ml of oxidized liposome. 20 mg of human serum albumin (HSA) was then added to the liposome solution, and the obtained solution was stirred at 25° C. for 2 hours. Then, 100 μl of 2M NaBH 3 CN was added to the PBS buffer solution (pH 8.0), and the obtained solution was stirred at 10° C. for one night to bond the HSA to the liposome membrane surface through a coupling reaction between the HSA and the ganglioside on the liposome. Then, 10 ml of HSA-bonded liposome solution was obtained through an ultrafiltration using an XM 300 membrane and a CBS buffer solution (pH 8.5). EXAMPLE 4 Bonding of Lactose Disaccharide to Human Serum Albumin (HSA) Bonded on Liposome Membrane Surfaces [0075] 50 μg, 200 μg, or 1 mg of lactose disaccharide (Wako Pure Chemical Co., Japan) was added to 0.5 ml of water solution having 0.25 g of NH 4 HCO 3 dissolved therein, and the obtained solution was stirred at 37° C. for 3 days. Then, the solution was filtered by using a filter of 0.45 μm to complete an amination reaction at the reduction terminal of the sugar chain and obtain 50 μg of glycosylamine compound of the lactose disaccharide. Then, 1 mg of 3,3′-dithiobis (sulfosuccinimidyl propionate) (DTSSP; Pierce Co., USA) serving as a crosslinking reagent was added to 1 ml of a part of the liposome solution obtained in Example 3. The obtained solution was then stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night. Then, the solution was subjected to ultrafiltration by using an XM 300 membrane and a CBS buffer solution (pH 8.5) to obtain 1 ml of liposome in which the DTSSP was bonded to the HSA on the liposome. Then, 50 μg of the glycosylamine compound of the lactose disaccharide was added to the liposome solution. The obtained solution was stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night. Then, the solution was subjected to ultrafiltration by using an XM 300 membrane and a PBS buffer solution (pH 7.2) to bond the lactose disaccharide to the DTSSP on the human serum albumin bonded on the liposome membrane surface. In this manner, 3 types of liposomes (2 ml each), differing in the amount of sugar chain bonded thereto (referred to as LAC-1 (50 μg), LAC-2 (200 μg), and LAC-3 (1 mg)), in which lactose disaccharide is bonded to the liposome through human serum albumin (FIG. 1) (total lipid mass: 2 mg, total protein mass: 200 μg, average particle size: 100 nm), were obtained. EXAMPLE 5 Bonding of 2′-Fucosyllactose Trisaccharide to Human Serum Albumin (HSA) Bonded on Liposome Membrane Surfaces [0076] 50 μg, 200 μg, or 1 mg of 2′-fucosyllactose trisaccharide (Wako Pure Chemical Co., Japan) was added to 0.5 ml of water solution having 0.25 g of NH 4 HCO 3 dissolved therein, and the obtained solution was stirred at 37° C. for 3 days. The solution was then filtered by using a filter of 0.45 μm to complete an amination reaction at the reduction terminal of the sugar chain and obtain 50 μg of glycosylamine compound of the 2′-fucosyllactose trisaccharide. Then, 1 mg of 3,3′-dithiobis(sulfosuccinimidyl propionate) (DTSSP; Pierce Co., USA) serving as a crosslinking reagent was added to 1 ml of a part of the liposome solution obtained in Example 3. The obtained solution was stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night. Then, the solution was subjected to ultrafiltration by using an XM 300 membrane and a CBS buffer solution (pH 8.5) to obtain 1 ml of liposome in which the DTSSP was bonded to the HSA on the liposome. Then, 50 μg of the glycosylamine compound of the 2′-fucosyllactose trisaccharide was added to the liposome solution. The obtained solution was stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night. Then, the solution was subjected to ultrafiltration by using an XM 300 membrane and a PBS buffer solution (pH 7.2) to bond the 2′-fucosyllactose trisaccharide to the DTSSP on the human serum albumin bonded on the liposome membrane surface. In this manner, 3 types of liposomes (2 ml each), differing in the amount of sugar chain bonded thereto (referred to as 2FL-1 (50 μg), 2FL-2 (200 μg), and 2FL-3 (1 mg)), in which 2′-fucosyllactose trisaccharide is bonded to the liposome through human serum albumin (FIG. 2) (total lipid mass: 2 mg, total protein mass: 200 μg, average particle size: 100 nm), were obtained. EXAMPLE 6 Bonding of Difucosyllactose Tetrasaccharide to Human Serum Albumin (HSA) Bonded on Liposome Membrane Surfaces [0077] 50 μg, 200 μg, or 1 mg of difucosyllactose tetrasaccharide (Wako Pure Chemical Co., Japan) was added to 0.5 ml of water solution having 0.25 g of NH 4 HCO 3 dissolved therein, and the obtained solution was stirred at 37° C. for 3 days. The solution was then filtered by using a filter of 0.45 μm to complete an amination reaction at the reduction terminal of the sugar chain to obtain 50 μg of glycosylamine compound of the difucosyllactose tetrasaccharide. Then, 1 mg of 3,3′-dithiobis(sulfosuccinimidyl propionate) (DTSSP; Pierce Co., USA) serving as a crosslinking reagent was added to 1 ml of a part of the liposome solution obtained in Example 3. The obtained solution was stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night. Then, the solution was subjected to ultrafiltration by using an XM 300 membrane and a CBS buffer solution (pH 8.5) to obtain 1 ml of liposome in which the DTSSP was bonded to the HSA on the liposome. Then, 50 μg of the glycosylamine compound of the difucosyllactose tetrasaccharide was added to the liposome solution. The obtained solution was stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night. Then, the solution was subjected to ultrafiltration by using an XM 300 membrane and a PBS buffer solution (pH 7.2) to bond the difucosyllactose tetrasaccharide to the DTSSP on the human serum albumin bonded on the liposome membrane surface. In this manner, 3 types of liposomes (2 ml each), differing in the amount of sugar chain bonded thereto (referred to as DFL-1 (50 μg), DFL-2 (200 μg), and DFL-3 (1 mg)), in which difucosyllactose tetrasaccharide is bonded to the liposome through human serum albumin (FIG. 3) (total lipid mass: 2 mg, total protein mass: 200 μg, average particle size: 100 nm), were obtained. EXAMPLE 7 Bonding of 3-Fucosyllactose Trisaccharide to Human Serum Albumin (HSA) Bonded on Liposome Membrane Surfaces [0078] 50 μg, 200 μg, or 1 mg of 3-fucosyllactose trisaccharide (Wako Pure Chemical Co., Japan) was added to 0.5 ml of water solution having 0.25 g of NH 4 HCO 3 dissolved therein, and the obtained solution was stirred at 37° C. for 3 days. The solution was then filtered by using a filter of 0.45 μm to complete an amination reaction at the reduction terminal of the sugar chain to obtain 50 μg of glycosylamine compound of 3-fucosyllactose' trisaccharide. Then, 1 mg of 3,3′-dithiobis (sulfosuccinimidyl propionate) (DTSSP; Pierce Co., USA) serving as a crosslinking reagent was added to 1 ml of a part of the liposome solution obtained in Example 3. The obtained solution was stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night. The solution was subjected to ultrafiltration by using an XM 300 membrane and a CBS buffer solution (pH 8.5) to obtain 1 ml of liposomes in which the DTSSP was bonded to the HSA on the liposome. Then, 50 μg of the glycosylamine compound of the 3-fucosyllactose trisaccharide was added to the liposome solution. The obtained solution was stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night. The solution was then subjected to ultrafiltration by using an XM 300 membrane and a PBS buffer solution (pH 7.2) to bond the 3-fucosyllactose trisaccharide to the DTSSP on the human serum albumin bonded on the liposome membrane surface. In this manner, 3 types of liposomes (2 ml each), differing in the amount of sugar chain bonded thereto (referred to as 3FL-1 (50 μg), 3FL-2 (200 μg), and 3FL-3 (1 mg)), in which the 3-fucosyllactose trisaccharide is bonded to the liposome through human serum albumin (FIG. 4) (total lipid mass: 2 mg, total protein mass: 200 μg, average particle size: 100 nm), were obtained. EXAMPLE 8 Bonding of Lewis X Trisaccharide to Human Serum Albumin (HSA) Bonded on Liposome Membrane Surfaces [0079] Liposomes comprising Lewis X Trisaccharide-bonded HSA on the liposome membrane surface were prepared according to the method of Example 4, with the exception that 50 μg of Lewis X trisaccharide (Calbiochem Co., USA) was used in place of the lactose disaccharide. 2 ml of the liposome (LX), in which Lewis X trisaccharide is bonded to the liposome through human serum albumin (FIG. 5) (total lipid mass: 2 mg, total protein mass: 200 μg, average particle size: 100 nm), was obtained. EXAMPLE 9 Bonding of Sialyl Lewis X Tetrasaccharide to Human Serum Albumin (HSA) Bonded on Liposome Membrane Surfaces [0080] Liposomes comprising sialyl Lewis X tetrasaccaride-bonded HSA on the liposome membrane surface were prepared according to the method of Example 5, with the exception that 50 μg of sialyl Lewis X tetrasaccaride (Calbiochem Co., USA) was used in place of the 2′-fucosyllactose trisaccharide. 2 ml of the liposome (SLX), in which sialyl Lewis X tetrasaccaride is bonded to the liposome through human serum albumin (FIG. 6) (total lipid mass: 2 mg, total protein mass: 200 μg, average particle size: 100 nm), was obtained. EXAMPLE 10 Bonding of 3′-Sialyllactosamine Trisaccharide to Human Serum Albumin (HSA) Bonded on Liposome Membrane Surfaces [0081] Liposomes comprising 3′-sialyllactosamine trisaccharide-bonded HSA on the liposome membrane surface were prepared according to the method of Example 6, with the exception that 50 μg of 3′-sialyllactosamine trisaccharide (Seikagakukogyou Co., Japan) was used in place of the difucosyllactose tetrasaccharide. 2 ml of the liposome (3SLN), in which 3′-sialyllactosamine trisaccharide is bonded to the liposome through human serum albumin (FIG. 7) (total lipid mass: 2 mg, total protein mass: 200 μg, average particle size: 100 nm), was obtained. EXAMPLE 11 Bonding of 6′-Sialyllactosamine Trisaccharide to Human Serum Albumin (HSA) Bonded on Liposome Membrane Surfaces [0082] Liposomes comprising 6′-sialyllactosamine trisaccharide-bonded HSA on the liposome membrane surface were prepared according to the method of Example 7, with the exception that 50 μg of 6′-sialyllactosamine trisaccharide (Seikagakukogyou Co., Japan) was used in place of the 3-fucosyllactose trisaccharide. 2 ml of the liposome (6SLN), in which 6′-sialyllactosamine trisaccharide is bonded to the liposome through human serum albumin (FIG. 8) (total lipid mass: 2 mg, total protein mass: 200 μg, average particle size: 100 nm), was obtained. EXAMPLE 12 Bonding of Tris (Hydroxymethyl) Aminomethane to Human Serum Albumin (HSA) Bonded on Liposome Membrane Surfaces [0083] For preparing a liposome as a comparative sample, 1 mg of 3,3′-dithiobis (sulfosuccinimidyl propionate) (DTSSP; Pierce Co., USA) serving as a crosslinking reagent was added to 1 ml of a part of the liposome solution obtained in Example 3. The obtained solution was stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night. The solution was then subjected to ultrafiltration by using an XM 300 membrane and a CBS buffer solution (pH 8.5) to obtain 1 ml of liposome in which the DTSSP was bonded to the HSA on the liposome. Then, 13 mg of tris (hydroxymethyl) aminomethane (Wako Co., Japan) was added to the liposome solution. The obtained solution was stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night. Then, the solution was subjected to ultrafiltration by using an XM 300 membrane and a PBS buffer solution (pH 7.2) to bond the tris (hydroxymethyl) aminomethane to the DTSSP on the human serum albumin bonded on the liposome membrane surface. In this process, an excess amount of tris (hydroxymethyl) aminomethane, that is 13 mg, already exists. Thus, the hydrophilization of the human serum albumin (HSA) bonded on the liposome membrane surface was simultaneously completed. In this manner, 2 ml of the liposome as the comparative sample (TRIS) in which the tris (hydroxymethyl) aminomethane is bonded to human serum albumin (FIG. 9) (total lipid mass: 2 mg, total protein mass: 200 μg, average particle size: 100 nm) was obtained. EXAMPLE 13 Hydrophilization of Human Serum Albumin Bonded on Liposome Membrane Surfaces [0084] For the 16 types of sugar-modified liposomes prepared in Examples 4 to 11, the respective HSA protein surfaces were separately hydrophilized through the following process. 13 mg of tris (hydroxymethyl) aminomethane was added to each of the 16 types of sugar-modified liposomes (2 ml each). The respective obtained solutions were stirred at 25° C. for 2 hours, and subsequently stirred at 7° C. for one night. The solutions were then subjected to ultrafiltration by using an XM 300 membrane and a PBS buffer solution (pH 7.2) to remove unreacted materials. In this manner, 2 ml of final product for each of the 16 types of hydrophilized sugar-modified liposome complexes (LAC-1, LAC-2, LAC-3, 2FL-1, 2FL-2, 2FL-3, DFL-1, DFL-2, DFL-3, 3FL-1, 3FL-2, 3FL-3, LX, SLX, 3SLN and 6SLN) (total lipid mass: 2 mg, total protein mass: 200 μg, average particle size: 100 nm) were obtained. EXAMPLE 14 Measurement of Lectin-Binding Activity Inhibiting Effect in Each Type of Sugar-Modified Liposome Complex [0085] The in vitro lectin-binding activity of each of the 16 types of hydrophilized sugar-modified liposomes prepared in Example 13 was measured through an inhibition test using a lectin-immobilized microplate by methods known in the art (see, e.g., Yamazaki, N., et al., Drug Delivery System, 14:498-505 (1999)). More specifically, a lectin (E-selectin; R&D Systems Co., USA) was immobilized on a 96 well-microplate. Then, 0.1 μg of biotinylated and fucosylated fetuin as a comparative ligand, and various types of sugar-modified liposome complexes having different densities (each including 0.01 μg, 0.04 μg, 0.11 μg, 0.33 μg or 1 μg of protein), were placed on the lectin-immobilized plate, and incubated at 4° C. for 2 hours. After washing with PBS (pH 7.2) three times, horseradish peroxidase (HRPO)-conjugated streptavidin was added to each of the wells. The respective test solutions were incubated at 4° C. for 1 hour, and then washed with PBS (pH 7.2) three times. Then, peroxidase substrates were added to the test solutions, and incubated at room temperature. Then, the absorbance at 405 nm of each of the test solutions was determined by a microplate reader (Molecular Devices Corp., USA). For the biotinylation of the fucosylated fetuin, each of the test solutions was subject to a sulfo-NHS-biotin reagent (Pierce Chemical Co., USA) treatment and refined by using a Centricon-30 (Amicon Co., USA). HRPO-conjugated streptavidin was prepared by oxidizing HRPO and bonding streptavidin to the oxidized HRPO through a reductive amination method using NaBH 3 CN. This measurement result is shown in Table 1. TABLE 1 Test Result showing Lectin-Binding Activity Inhibiting Effect of Each Type of Sugar-Modified Liposome Complex Inhibiting Effect (absorbance) at each density Liposome of liposome complexes (μg protein) Complex 0.01 μg 0.04 μg 0.11 μg 0.33 μg 1 μg LAC-1 0.115 0.114 0.112 0.112 0.105 LAC-2 0.112 0.109 0.104 0.104 0.097 LAC-3 0.119 0.118 0.112 0.109 0.108 2FL-1 0.121 0.115 0.106 0.097 0.067 2FL-2 0.131 0.119 0.116 0.111 0.079 2FL-3 0.149 0.133 0.122 0.104 0.073 DFL-1 0.167 0.158 0.146 0.131 0.108 DFL-2 0.136 0.134 0.133 0.120 0.106 DFL-3 0.163 0.150 0.134 0.118 0.097 3FL-1 0.138 0.131 0.121 0.113 0.085 2FL-2 0.148 0.134 0.128 0.123 0.092 3FL-3 0.149 0.134 0.129 0.128 0.110 LX 0.199 0.195 0.195 0.195 0.129 SLX 0.105 0.100 0.100 0.084 0.073 2SLN 0.175 0.158 0.144 0.131 0.095 3SLN 0.256 0.245 0.233 0.200 0.151 EXAMPLE 15 125 I-Labeling of Each Type of Sugar-Modified Liposome through the Chloramine T Method [0086] A chloramine T (Wako Pure Chemical Co., Japan) solution and a sodium disulfite solution were prepared at 3 mg/ml and 5 mg/ml, respectively. 50 μl of the 16 different types of hydrophilized sugar-modified liposomes prepared in Example 13, and the liposome of Example 12, were put into separate Eppendorf tubes. Then, 15 μl of 125 I-NaI (NEN Life Science Product, Inc. USA) and 10 μl of chloramine T solution were added thereto and reacted therewith. 10 μl of chloramine T solution was added to the respective solutions every 5 minutes. After 15 minutes from the completion of the above procedure repeated twice, 100 μl of sodium disulfite serving as a reducer was added to the solutions to stop the reaction. Then, each of the resulting solutions was placed on a Sephadex G-50 (Phramacia Biotech. Sweden) column chromatography, and eluted by PBS to purify a labeled compound. Finally, a non-labeled liposome complex was added to each of the solutions to adjust a specific activity (4×10 6 Bq/mg protein). In this manner, 16 types of 125 I-labeled liposome solutions were obtained. EXAMPLE 16 Measurement of Transfer Rate of Each Type of Sugar-Modified Liposome Complex to Tissues of Mice with Cancer [0087] Using an oral sonde, 13 of the different types of 125 I-labeled, hydrophilized sugar-modified liposomes of Example 15 (LAC-1, LAC-2, LAC-3, 2FL-1, 2FL-2, 2FL-3, DFL-1, DFL-2, DFL-3, 3FL-1, 3FL-2, 3FL-3 and TRIS) (equivalent to 3 μg of protein per mouse) were administered to male ddY mice (7 weeks of age) which had abstained from food, except for water, for one whole day, in an amount of 0.2 ml which is equivalent to 3 μg of protein per mouse. After 10 minutes, 1 ml of blood was taken from descending aorta under Nembutal anesthesia. Then, 125 I-radioactivity in the blood was measured with a gamma counter (Aloka ARC 300). Further, in order to check the in vivo stability of each type of liposome complex, serum from each mouse's blood was subjected to chromatography using a Sephadex G-50. As a result, most of the radioactivity in each sample of serum was found in void fractions having a high molecular weight, and it was proved that each type of liposome complexes has a high in vivo stability. The radioactivity transfer rate from intestine to blood was represented by the ratio of the radioactivity per ml of blood to the total of given radioactivity (% dose/ml blood). This measurement result is shown in FIGS. 10 to 13 . EXAMPLE 17 Measurement of Distribution Rate of Each Type of Sugar-Modified Liposome Complex to Tissues of Mice with Cancer [0088] Ehrlich ascites tumor (EAT) cells (about 2×10 7 cells) were implanted subcutaneously into the femoral region in male ddY mice (7 weeks of age), and the mice were used in this test after the tumor tissues grew to 0.3 to 0.6 g (after 6 to 8 days). Five of the different types of 125 I-labeled, hydrophilized sugar-modified liposome complexes (LX, SLX, 3SLN, 6SLN and TRIS) of Example 15 were injected into the tail veins of the mice in an amount of 0.2 ml which is equivalent to 3 μg of protein per mouse. After 60 minutes, tissues (blood, liver, spleen, lung, brain, inflammatory tissues around cancer, cancer and lymph node) were extracted, and the radioactivity of each of the extracted tissues was measured with a gamma counter (Aloka ARC 300). The distribution rate of the radioactivity in each of the tissues was represented by a ratio of the radioactivity per gram of each of the tissues to the total of given radioactivity (% dose/g tissue). This measurement result is shown in FIGS. 14 to 21 . [0089] The results from these experiments show that the sugar-modified liposomes of the present invention are innovative in that they are excellent in intestinal absorption and are capable of being administered via the intestine, which has not been found in conventional liposome related products. In addition, the intestinal absorption can be controlled by adjusting the identity and amount of the sugar chain bonded to the liposomes. [0090] Furthermore, the in vivo mobility of sugar-modified liposomes of the present invention, and their ability to target selected tissues in vivo, can be facilitated or suppressed in a living body by utilizing the difference in the molecular structure of the sugar chain, and varying their amounts. [0091] Thus, the sugar-modified liposomes of the present invention can be used to deliver drugs or genes through the intestine efficiently and safely without any side effects. They may also be used as an effective delivery mechanism for selectively delivering drugs or genes to target tissues such as blood, liver, spleen, lung, brain, cancer tissues, inflammatory tissue, or lymph node, and can be used in DDS materials in light of their enhanced mobility. Thus, the liposomes of the present invention are useful particularly in the medical and pharmaceutical fields.

The present invention provides a sugar-modified liposome having a sugar chain bonded to its membrane surface, preferably through a linker protein, and having excellent absorption qualities, particularly in the intestine. The molecular structure and quantity of the sugar chain is selectively varied to allow the liposome to be delivered in a targeted manner to selected cells and tissues. The liposome is applicable to medicinal drugs, cosmetics and other various products in the medical/pharmaceutical fields, and it is especially useful in a therapeutic drug delivery system that recognizes target cells and tissues, such as cancer cells, and in the delivery of drugs or genes locally to a selected region, or in a diagnostic cell/tissue sensing probe.

BACKGROUND AND SUMMARY The present invention relates to the field of computer systems. More particularly, the invention relates to a method and system for database optimization. A “query” is a statement or collection of statements that is used to access a database. Specialized query languages, such as the structured query language (“SQL”) are often used to interrogate and access a database. Many types of queries include at least the following. First, the identity of the database object(s) being accessed to execute the query (e.g., one or more named database tables). If the query accesses two or more database objects, what is the link between the objects (e.g., a join condition or column). The typical query also defines selection criteria, which is often referred to as a matching condition, filter, or predicate. Lastly, a query may define which fields in the database object are to be displayed or printed in the result. Optimization is the process of choosing an efficient way to execute a query statement. Many different ways are often available to execute a query, e.g., by varying the order or procedure in which database objects and indexes are accessed to execute the query. The exact execution plan or access path that is employed to execute the query can greatly affect how quickly or efficiently the query statement executes. Cost-based optimization is an approach in which the execution plan is selected by considering available access paths to determine the lowest cost approach to executing the query. In one approach, cost-based optimization consists of the following steps: (1) generating a set of potential execution plans for the database statement to be executed; (2) estimating the cost for each execution plan; and (3) comparing the costs of the execution plans to identify the execution plan having the lowest cost. Conceptually, the term “cost” relates to the amount of a given resource or set of resources needed to process an execution plan. Examples of such resources include I/O, CPU time, and memory. Various measures may be used to identify the execution plan having the lowest cost. For example, the cost-based approach may be used to identify the execution plan providing either the best throughput or the best response time. Many database optimizers use statistics to calculate the “selectivity” of predicates and to estimate the cost of performing database operations. Statistics quantify characteristics of database and schema objects, such as the data distribution and storage characteristics of tables, columns, indexes, and partitions. Selectivity refers to the proportion or fraction of a database object corresponding to a query predicate. An optimizer uses the selectivity of a predicate to estimate the cost of a particular access method and to determine optimal join order. Statistics should be gathered on a regular basis to provide the optimizer with needed information about schema objects. Significant costs may be incurred to collect and maintain statistics for database objects. To reduce this collection cost and improve performance, many database systems use data sampling to reduce the amount of data that must be collected to provide statistics used by the optimizer. With data sampling, only a portion of the rows within a database table is accessed to generate a set of statistics for the entire table or column. The results of the data sampling is thereafter scaled upward to extrapolate the statistics values for the entire population. However, different data distributions may require different sample sizes in order to obtain accurate statistics. If a too-small sample size is selected, then the statistics may be inaccurate, which could lead to sub-optimal execution plans and poor query performance. If a too-large sample size is selected, then resources are wasted to collect more data than is needed to provide accurate statistics. Consequently, it is desirable to use only the minimal sample size needed for accurate statistics collection. In addition to statistics, optimizers often use data value histograms to select an optimal execution plan. A data value histogram is a structure that provides estimates of the distribution of data values in a database object. A histogram partitions the data object values in a set of individual “buckets”, so that all values corresponding to a given range fall within the same histogram bucket. The histogram provides information that is helpful in determining the selectivity of a predicate that appears in a query. In a height-balanced histogram, each bucket of the histogram corresponds to an equal number of rows in a table. The boundaries of the buckets shrink or grow so that all buckets maintain the same number of entries. The useful information provided by the histogram is the range of values that corresponds to each bucket, e.g., the endpoints for each bucket of the histogram. Consider a column C with values between 1 and 100 in which the column data is uniformly distributed. FIG. 1 a shows a height-balanced histogram plotted for this column having ten buckets. The number of rows in each bucket of the histogram is one-tenth the total number of rows in the table. Since the data values are evenly distributed, the endpoints of the buckets are also evenly spaced. Now consider a second column having 100 rows for which column data values are not evenly spaced, in which ninety rows contain the value “1” and the other ten rows contain a column value between 2 and 100. FIG. 1 b shows this column plotted in a height balanced histogram of ten buckets. Since ninety percent of the rows have the value “1”, nine of the ten buckets in the histogram of FIG. 1 b also correspond to the value “1”. Thus, it can be seen that nine of the ten buckets in the histogram of FIG. 1 b have endpoints that end in the number “1”. The last bucket corresponds to the ten rows in the column having data values between “2” and “100”. In operation, such a histogram provides an optimizer with instant knowledge of the selectivity of particular values of a column. This selectivity information can be used, for example, to determine whether either a full table scan or an index access provides the most efficient path to satisfying a query against the database table corresponding to the histogram. Other types of histograms also exist. For example, another histogram used by optimizers is the width-balanced histogram, in which column data is divided into a number of fixed, equal-width ranges and the histogram is organized to count the number of values falling within each range. A histogram may not always provide an appreciable benefit. For example, a histogram may not be useful for a data set having uniform data distribution, since it can be assumed that all data within that set are equally distributed and therefore the histogram will not provide any additional useful information. If a histogram is desired, a significant amount of resources may be needed to collect, maintain, and use histograms. Therefore, it makes sense to only create, store, and/or use a histogram when such a histogram provides benefits greater than the expense of the histogram. However, conventional database systems typically rely upon the skill and knowledge of individual database administrators to manually decide whether histograms should or should not be collected for columns in the database. While guidelines may be provided to assist this decision-making, this manual process by administrators often leads to inconsistent and erroneous decisions resulting in the collection and storage of unneeded histograms, or the failure to collect histograms that could provide more efficient query processing. The present invention provides a method and system for determining when to collect histograms. In an embodiment, the invention provides a mechanism for automatically deciding when to collect histograms upon request from the user. This decision is based on the columns the user is interested in, the role these columns play in the queries as submitted to the system, and the underlying distribution for these columns, e.g., as seen in a random sample. The user specifies which columns are of interest, and the database is configured to collect column usage information that describes how each column is being used in the workload. This column usage information could be stored in memory and periodically flushed to disk. Given a set of potential columns, the distribution of those columns is viewed in combination with the usage information to determine which columns should have histograms. The invention also provides a system and method for determining an adequate sample size for statistics collection. In one embodiment, the invention provides a mechanism for automatically determining an adequate sample size for both statistics and histograms. This is accomplished via an iterative approach where the process starts with a small sample, and for each attribute which may need more data, the sample size is increased while restricting the information collected to only those attributes that require the larger sample. Further details of aspects, objects, and advantages of the invention are described below in the detailed description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a further understanding of the invention and, together with the Detailed Description, serve to explain the principles of the invention. FIGS. 1 a and 1 b show example histograms. FIG. 2 shows a flowchart of a process for determining sample size for statistics collection according to an embodiment of the invention. FIG. 3 shows a flowchart of a process for histogram determination according to an embodiment of the invention. FIG. 4 shows a flowchart of an alternate process for histogram determination according to an embodiment of the invention. FIGS. 5 and 6 are diagrams of system architectures with which the present invention may be implemented. DETAILED DESCRIPTION The invention is described with reference to specific embodiments. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The reader is to understand that the specific ordering and combination of process actions shown in the process flow diagrams and system components in component diagrams described herein are merely illustrative, and the invention can be performed using different, additional, or different combinations/ordering of process actions and components. For example, the invention is particularly illustrated herein with reference to specific database objects such as tables, columns, and rows, but it is noted that the inventive principles are equally applicable to other types of database objects. The specification and drawings are, accordingly, to be regarded in an illustrative rather than restrictive sense. FIG. 2 shows a flowchart of a process for determining sample sizes for statistics collection, according to an embodiment of the invention. At step 200 , an initial sample size is selected for statistics collection. In an embodiment, the selected sample size could be expressed as a percentage of the rows in a table. Other measures could be used to express sample size, such as an exact number of rows for the table. At step 202 , rows in the table are identified based upon the initially selected sample size. In an embodiment, this is accomplished by attempting to select the number of rows in the table corresponding to the percentage value used to express the initially selected sample size. For example, consider if the initially selected sample size is 20% and the number of rows in the table is 1000. For this example, the expected number of rows to be identified in step 202 is (1000)*(0.20)=200 rows. One way to achieve this is to provide a function (e.g., a “sample( )” function) that chooses rows from the table based upon the selected percentage value, in which each row is individually faced with a given percentage chance of being selected. If the sampling percentage is 20%, then each row in the column individually faces a 20% chance of being selected. In this manner, over the entire table, it is likely that approximately 20% of the rows in the table will be selected. The exact rows to be selected will be subject to a certain amount of randomization, and it is possible that the exact number of rows actually selected will be greater or smaller than 20%. The statistics gathered based upon this sampling can later be used to extrapolate statistics for the entire table. At step 204 , a determination is made regarding whether the number of sample rows identified in step 202 is adequate. In an embodiment, this step is performed by determining whether statistics for the identified rows using the initial sample size can be adequately scaled upward to extrapolate accurate statistics for the entire table. One approach to accomplishing this is to compare the selected number of rows with a minimum value for the particular statistics for which sampling is performed. For example, consider if the statistic being addressed by the sampling is the “Number of Rows in Table.” A minimum value, such as “2500” can be established for this type of statistic. If the identified number of rows from step 202 is less than 2500 rows, then the sample size or sample percentage is increased ( 208 ), and steps 202 and 204 are repeated until the minimum sample size is achieved. If the number of rows identified in step 202 meets or exceeds the minimum value, then the sample size is adequate ( 206 ). It is noted that different statistics may require differing tests to determine whether rows sampled during step 202 can be adequately scaled upward to provide statistics for the entire table. The following are additional examples of statistics used for database optimizers: 1) average column length; 2) number of distinct values in column; 3) minimum value in column; and 4) maximum value in column. For the average length, minimum, and maximum statistics, the number of rows sampled during step 202 can be compared to another minimum value, e.g., “919”, to determine whether the sample size is adequate. FIG. 4 is a flowchart of a process for determining whether a histogram should be collected or saved according to an embodiment of the invention. At step 402 , column usage is tracked during workloads executed against a table. In an embodiment, this is accomplished by marking individual columns while executing queries against those columns. A recordation is made regarding the type of predicate that is evaluated against a column. For example, this type of recordation tracks whether, and how often, an equality, range or like predicate is evaluated against a column. At step 404 , a determination is made whether data skew exists for the column values. The predicate type for a particular column and the data skew within that column are analyzed to determine whether a histogram should be collected for the column ( 406 ). In an embodiment, if equality and/or equijoin predicates are evaluated against a column and the column data exhibits non-uniform value repetition, then a histogram should be collected and/or saved for the column. If like or range predicates are evaluated against a column and the column data exhibits non-uniformity in range, then a histogram should be collected and/or saved. The meaning of “non-uniform value repetition” and “non-uniformity in range” is defined below according to one embodiment of the invention. Instead of, or in addition to, the process of FIG. 4, the process shown in FIG. 3 can be used to determine whether a histogram should be collected or saved for a table column. If data sampling is being performed, then a determination is made at step 300 whether the sample size is adequate. If not, then the sampling rate is adjusted upward to collect an adequate sample size. In one embodiment, if the number of non-null column values in the sample is less than 2500, then the sample rate is increased to provide more samples. At step 302 , a determination is made regarding the expected number of buckets for the histogram. At step 304 , data uniformity/range skew is evaluated for the data sample values with respect to the expected histogram buckets. In an embodiment, this is accomplished by gathering frequency and histogram information for the column values. For example, a simple query can be executed to collect distinct values and their counts for a column. At step 306 , a determination is made whether the column values are uniform. In an embodiment, this determination checks whether any values repeat more than other values in the column, or whether there are any range skews in the data. If so, then the data is non-uniform. If the data is non-uniform, then a histogram is collected for the column ( 310 ). If the column data is uniform then the values in the column are considered to be equally distributed; therefore, either no histogram is collected or a previously collected histogram is not saved/used ( 308 ). Illustrative Embodiment The present section describes pseudocode to implement an illustrative embodiment of the invention. Initially, the illustrative embodiment begins by building an array of columns needing statistics. Then, the illustrative process primes data structure bits that represent which statistics need to be gathered for which columns. The process may re-invoke this procedure when auto-increasing the sample size to re-set the still necessary bits for statistics requiring an increased sample size. The process creates a list of query statements needed to gather all statistics—this “select” list may be reused across all partitions and subpartitions. These queries are executed to gather statistics for every table/partition object requested. Finally, the illustrative procedure sets the gathered statistics in a data dictionary. The sample size used while gathering statistics is automatically adjusted during the procedure to ensure adequate sample size for the particular statistics being collected. The following comprises high-level pseudocode for the illustrative embodiment: if auto sample size do a quick row count estimate of the object initialize all of the statistics bits for the columns while there are still unresolved statistics generate the from clause for the query execute the basic query work on all of the desired histograms evaluate the basic statistics if some statistics are not ready (need larger sample size) construct a new select list using the current statistics bits The following table defines variables used in the illustrative pseudocode. TABLE 1 Term Definition p Sampling fraction (between 0.0 and 1.0) n Number of rows in the table avg Average column length statistic min/max Minimum/maximum column value statistic nv Number of null column values statistic ndv Number of distinct values statistic s Number of rows seen in the sample snnv Number of non-null column values seen in the sample sndv Number of distinct values seen in the sample mnb Maximum number of buckets allowed in the histogram The following is pseudocode for the top level routine for gathering statistics and for determining whether a histogram should be collected: estimate n—use block sample count(*) on user's table initialize_gather_bits( ) while (some statistics still need to be (re)collected) generate_from_clause( )—includes possible materialization of new table execute_basic( ) execute_hist( ) evaluate_basic( ) This top level pseudocode executes the main functions that comprise the statistics gathering processes according to one embodiment of the invention. The initialize_gather_bits( ) function is a procedure which takes in the array of columns for which statistics need to be collected and sets bits representing which statistics are needed. These bits are later individually cleared after gathering statistics and evaluating their probable accuracy. The function is called initially so that the select list can be generated from it for all objects. It is later called again to reset the bits for each new object (e.g., table/partition/subpartition). The process takes in the list of columns (including statistics bits) and creates a select list to be used to gather basic statistics (not including histograms). In an embodiment, the process ensures that the select list does not contain more functions than the server can handle at once, e.g., only 256 distinct aggregates. If it cannot fit them all in one statement, the caller is informed of which columns are included. The generate_from_clause( ) function has the responsibility of generating the FROM clause for the basic query and all the histogram queries. In one embodiment, each histogram uses a separate query, and therefore employs a separate scan of the data. If many scans are required and involve sampling the underlying table, it may be beneficial to materialize the sample once and then pass over that multiple times. If that is the case, this procedure in one embodiment will generate a temporary table and populate it with a sample. The execute_basic( ) function handles the basic statistics query to parse, execute, and fetch information from the database objects. In an embodiment, the query is generated earlier in the process and the column array provides sufficient information to infer the select list. The evaluate_basic( ) procedure looks at the fetched basic statistics and tries to scale them up. This procedure clears the bits for all statistics that are acceptably scaled, and suggests a larger sampling percentage if some statistics need to be recollected. The execute_hist( ) procedure is the driver for collecting and evaluating the histogram statistics. This function looks over all columns that are marked as possibly needing histograms. It then collects a frequency histogram, a height histogram, or both, depending upon the expected number of distinct values and the requested number of buckets. The following comprises pseudocode for an embodiment of the initialize_gather_bits( ) function, in which the following statistics are collected: nv, ndv, min, max, and avg. for each column the user requested mark a bit to indicate need to collect the following statistics: nv, ndv, min, max, avg if there is a need to collect a histogram (see results of FIG. 4) mark a bit indicating this The following comprises pseudocode for an embodiment of the generate_from_clause( ) function, which establishes the initial sampling fraction p for the statistics gathering process: if first time, set p to 5500/n—try for 5500 rows otherwise, p is passed in to this function if ((p<=0) or (p>=0.15)) set p to 1.0—don't sample if p<1.0 and there are multiple passes (due to histograms) materialize the sample in another table and use that table instead In the illustrative embodiment, the process attempts to collect 5500 rows. To accomplish this, it is useful to know in advance the number of rows in the table. Based upon the number of rows, the sampling fraction p is established as shown in the pseudocode. If the number of rows is not known, then estimate this value. Certain thresholds can be established for the sampling fraction, beyond which the sampling fraction is set to 1. Under certain circumstances, it may make sense to create another table to hold the sampled data from the column. For example, if multiple passes are needed, e.g., because histograms are to be collected, then the samples are materialized into a table to prevent repeated accesses to the larger base table. The execute_basic( ) function builds up one or more queries to retrieve sampled data and calculates the desired statistics (excluding histograms in an embodiment). The one or more queries are then executed to retrieve the results for evaluation, as set forth below. In an embodiment, the one or more queries samples rows from the table based upon the sampling fraction p that was previously established. The evaluate_basic( ) function determines whether the number of rows sampled according to the sampling fraction p can be adequately scaled upward for the entire table. The following comprises pseudocode for an embodiment of the evaluate_basic( ) function: if(p<1.0) if(s<2500)—too small a sample bump up p accordingly n=s/p for each column clear all non-histogram bits that indicate which statistics to collect if nv bit was set nv=n−snnv/p if (avg, min, or max bit was set) and (snnv<919) bump up p accordingly set avg, min, and max bits again for next pass if ndv bit was set try to scale it up * if cannot scale upward  bump up p accordingly  set ndv again for next pass else—this was not an estimate set all requested statistics The pseudocode first checks that at least 2500 rows were sampled based upon the current sampling fraction (p). If not, then the sampling fraction is adjusted upward and the table is re-sampled. If a sufficient number of rows has been collected, then the number of rows (n) is estimated based upon the following: n=s/p, where s represents the number of rows that have been collected. For the average length, minimum, and maximum column value statistics (avg, min, max), the pseudocode checks that at least 919 non-null column values (snnv) are detected in the sample. If so, then these values are considered adequate for the entire table. If not, then the sampling fraction p is increased for the next pass through the table. For the number of distinct values statistic (ndv), the pseudocode attempts to scale this statistic up for the entire table. If the statistic based upon the sampled rows cannot be scaled upward, then the sampling fraction is increased for the next pass through the table. The following comprises pseudocode for scaling ndv and density (defined below) statistics according to an embodiment of the invention: sdiv:=sndv/snnv if ((snnv<100) or ((snnv>=100) and (snnv<500) and (sdiv>0.3299)) or ((snnv>=500) and (snnv<1000) and (sdiv>0.4977)) or ((snnv>=1000) and (snnv<2000) and (sdiv>0.5817)) or ((snnv>=2000) and (snnv<5000) and (sdiv>0.6634)) or ((snnv>=5000) and (snnv<10000) and (sdiv>0.7584)) or ((snnv>=10000) and (snnv<1000000) and (sdiv>0.8169)) or ((snnv>=1000000) and (sdiv>0.9784))) cannot reliable use kkesdv to scale the value else can use kkesdv scaling reliably nnv:=snnv/p if ((sndv=snnv) and ((snnv>=29472) or ((nnv<10000) and (snnv>=708)) or ((nnv<40000) and (snnv>=1813)) or ((nnv<160000) and (snnv>=4596)) or ((nnv<640000) and (snnv>=11664)))) then can use linear scaling reliably—ndv:=sndv*1/p else cannot reliably use linear scaling to scale the value The following comprises pseudocode for an embodiment of the kkesdr scaling function: x 1 :=sndv x 2 :=nnv stay_loop:=true while (stay_loop and (x 1 <=x 2 ) x:=floor((x 2 +x 1 )/2) y 2 :=x*(1−power(1−(1/x), snnv)) if (sndv<y 2 ) x 2 :=x−1 elseif (sndv>y 2 ) x 1 :=x+1 else stay_loop:=false ndv:=x The execute_hist( ) function determines whether a histogram should be collected. The following comprises pseudocode for an embodiment of the execute_hist( ) function: for each column with the histogram bit set if ((p<1.0) and (snnv<2500)) not enough data—bump up p for next pass accordingly else if # buckets specified via an integer or repeat set mnb to that value else set mnb to min(75,(max(200, snnv/26))) estimate the ndv based on prior information if available if (estimated ndv<(mnb*0.75))—probably a frequency histogram execute_frequency( ) if still need to collect histogram execute_height( ) As before, the pseudocode checks whether 2500 rows have been collected during the sampling process. If not, then the sampling fraction (p) is increased for the next pass through the table. The maximum number of buckets (mnb) is set as shown in the pseudocode. The number of distinct values (ndv) is estimated, possibly based upon a previous pass through the table and the prior execution of the evaluate_basic( ) function. If it is desired to collect a histogram and the estimated ndv value is below a given threshold (mnb*0.75), then a frequency histogram is generated in an embodiment. A frequency histogram is often appropriate for a column having a small number of distinct values. In a frequency histogram, the endpoints of multiple buckets have the same endpoint value (because the same value entry is in multiple buckets). For this reason, buckets having the same endpoint values often do not need an explicitly expressed endpoint. This provides one or more “bucket gaps” in the histogram that allows comparatively cheap storage and compressed representation of such frequency histograms. If this type of data distribution is identified, then the process preferably creates a frequency histogram using the execute_frequency( ) function. If it is desired to collect a histogram and the ndv value is greater than an established threshold, then the procedure generates a height-balanced histogram using the execute_height( ) function in an embodiment of the invention. The following comprises pseudocode for an embodiment of the execute_frequency( ) function: build up frequency query and execute it if (ndv<=mnb)—have a good frequency histogram clear histogram collection bit The following pseudocode can be used to build up a frequency query according to an embodiment of the invention: select c, count(*) from t sample (s) where c is not null group by c order by c; This query collects column values from a table and performs a count of the values. The following comprises pseudocode for an embodiment of the execute_height( ) function: build up a height-balanced query and execute it check for non-uniformity if non-uniformity exists try to scale the multiplicative inverse of the density if it can be successfully scaled—histogram is ready clear histogram collection bit else clear histogram collection bit—no histogram needed In this pseudocode, the column values are checked for non-uniformity. If the column values are uniform, then no histogram is collected. Otherwise, the pseudocode attempts to scale the multiplicative inverse of the density using the previously described process for scaling ndv. In prior evaluations, the number of repetitions was considered uniform over the values; but once histograms are introduced, the popular values can be removed to remove influence upon non-popular values in the histogram. According to an embodiment, a popular value is a value that corresponds to more than one endpoint in a height-balanced histogram. All values that are not popular are considered non-popular. Density is the expected number of repeated occurrences of a non-popular value. In one embodiment, density can be calculated as the sum of the square of the repetition counts for non-popular values divided by the product of the number of rows in the table and the number of non-popular values in the table. The following comprises pseudocode for building up a height-balanced query according to one embodiment of the invention: select maxbkt, min(value) minval, max(value) maxval, sum(rep) sumrep, sum(repsq) sumrepsq, max(rep) maxrep, count(*) bktndv from ( select value, max(bkt) maxbkt, count(value) rep, count(value)*count(value) repsq from ( select c as value, ntile(mnb) over (order by c) bkt from t sample(s) where c is not null ) group by value; ) group by maxbkt order by maxbkt; Here, the inner select statement calls an ntile( ) function, which creates a height-balanced histogram and places data sample values into appropriate buckets in the histogram. In an embodiment, such a function creates an uncompressed histogram and returns a number representing the bucket that a value falls into. The repetition counts (and square of repetition counts) are selected in the middle statement. The outer loop performs a count and checks the values and buckets for the result set. The max and min values for the buckets are reviewed to obtain the histogram endpoints. Density, which is related to the selectivity of non-popular values in the data sample, is calculated in this procedure using the function results from the outer loop. This is computed in an embodiment by looking at the number of repetitions of a non-popular value. The result of this query is that one row is obtained per bucket, with missing buckets coming from the more popular values. Each row will have the minimum and maximum value for that bucket, along with the number of rows in that bucket, the sum of the repetition counts and square of the repetition counts for rows in that bucket, and the number of repetitions for the most popular value in that bucket. All missing buckets have been folded into the nearest bucket that is larger. For example, consider if the process ends up with the following: maxbkt minval maxval sumrep sumrepsq maxrep 1 1 2 2 2 1 4 3 4 9 65 8 5 5 5 3 9 3 6 6 8 4 6 2 8 9 10 6 20 4 This would mean that the number 3 is popular because it is the largest value in the missing buckets 2 and 3 . Notice that the number 9 is not a popular value because it is only the largest value of a single bucket, bucket 7 , and thus would only appear once as a histogram endpoint. To calculate density, the influence of the popular value, 3 , would be removed. Since the value 3 appears 8 times, the number 8 is subtracted from the sumrep sum and 64 (square of 8) from the sumrepsq sum. This enables the computation at a density which is based upon the number of rows in the table, the number of non-popular values in the column, and the sum of the square of the repetition counts of non-popular values. The following pseudocode provides an illustrative embodiment of the invention for histogram determination that was generally described with respect to FIG. 4 . for each column, c, for which a histogram is considered if the user has specified size create and save a histogram with number of buckets=requested size else if the user has specified size repeat if c already has a histogram with b buckets create and save a histogram with b buckets else if the user has specified size skewonly create a histogram if the created histogram exhibits equality or range skew save it in the dictionary else if the user has specified size auto check the dictionary for column usage information if c has been in a predicate involving an equality, range, or like create a histogram if c appeared in an equality (including equijoin) predicate if the histogram exhibits non-uniformity in value repetition  save it in the dictionary if c appeared in a like or range predicate (not involving join) if the histogram exhibits non-uniformity in range save it in the dictionary any prior histogram on c will be removed The first portion of the pseudocode relates to specific instructions from a user to create a histogram, which results in the creation of the desired histogram. The specific histogram is created without a determination as to whether it is actually needed. Alternatively, the invention can be adapted to automatically check whether a histogram specifically called for by a user should actually be collected and/or saved. The second portion of the pseudocode relates to automated determination of histogram collection. In this illustrative embodiment, the following items of information are utilized for histogram determination: 1) the subset of columns for which the user wants to gather statistics; 2) the columns which already have histograms created for them; 3) column usage information; and 4) the distribution of data, e.g., as seen in a data sample. Because data distribution information is involved, this process may be advantageously used in conjunction with the process of FIG. 2 for automated sample size determination. In the illustrative embodiment, column usage information is considered in conjunction with data distribution information for that column to determine whether a histogram should be collected and stored. Column usage information includes, for example, the type of predicates that is executed against the column. The data skew of the column is evaluated against the type of predicate for that column to determine whether a histogram is needed. When parsing a cursor for the first time in an embodiment, the cost-based optimizer looks at the statistics on all of the objects (tables, columns, etc.) involved in the statement. For each column in the where clause, it will estimate the selectivity of the predicate involving that column. At this point, the system will make an entry in the data structure for the column indicating what type of predicate it was involved in. In an embodiment, column usage information is collected every time a user hard-parses a statement, in which a bit is marked in memory for the column usage information. Whenever information is flushed to disk, these bits indicate whether to increment the appropriate dictionary columns. For example, if a query containing a column with a range predicate was hard parsed since the last flush, the system will increment the range_predicate counter for that column when the next flush procedure takes place, as well as updating the timestamp. One reason for using counters on disk is to provide a better feel for the importance of the predicate. Counters can also be used in memory, but may result in expensive overhead. In the illustrative pseudocode, a histogram is created if the column is involved in equality, range, or like predicates. In an embodiment, the histogram is created based on a sampled portion of the column, and is preferably created using a small sample of the entire population that is sufficient to both determine the need for histograms and produce histograms which are representative of the entire population. The number of buckets in the histogram could be based on the sample size. The range max and min is selected based upon the data samples. Values in the data samples are placed into the selected buckets. The process then counts the number of equi-height endpoints that fall within the equi-width buckets. The buckets are reviewed to determine if any buckets are overly large or small. If so, then it is likely that the column does not have uniform data distribution, thereby indicating range skew. In addition, the act of creating a histogram also provides an estimate for the number of distinct values, providing an extra benefit even if the histogram is later discarded. If an equality or equijoin predicate is involved, then the histogram is saved only if the histogram exhibits non-uniformity in value repetition. For purposes of this example, a column will be considered to have non-uniform value repetition if any value is popular, e.g., repeats as an endpoint in the histogram. If a like or range predicate is involved, then the histogram is saved only if the histogram exhibits non-uniformity in range. In one embodiment, a column is considered to have non-uniformity in range if it passes the following test: given that the created histogram had b equi-height buckets divide the range (max−min) into b equi-width buckets sum=0 for each equiwidth bucket count the number of equi-height endpoints that fall in the bucket sum+=(count*count) if (sum/b)>1.7 this column is considered to be non-uniform in range For a uniform column, the equi-height endpoints would coincide with the equi-width endpoints, and the sum would simply be b. SYSTEM ARCHITECTURE OVERVIEW Referring to FIG. 5, in an embodiment, a computer system 520 includes a host computer 522 connected to a plurality of individual user stations 524 . In an embodiment, the user stations 524 each comprise suitable data terminals, for example, but not limited to, e.g., personal computers, portable laptop computers, or personal data assistants (“PDAs”), which can store and independently run one or more applications, i.e., programs. For purposes of illustration, some of the user stations 524 are connected to the host computer 522 via a local area network (“LAN”) 526 . Other user stations 524 are remotely connected to the host computer 522 via a public telephone switched network (“PSTN”) 528 and/or a wireless network 530 . In an embodiment, the host computer 522 operates in conjunction with a data storage system 531 , wherein the data storage system 531 contains a database 532 that is readily accessible by the host computer 522 . Note that a multiple tier architecture can be employed to connect user stations 524 to a database 532 , utilizing for example, a middle application tier (not shown). In alternative embodiments, the database 532 may be resident on the host computer, stored, e.g., in the host computer's ROM, PROM, EPROM, or any other memory chip, and/or its hard disk. In yet alternative embodiments, the database 532 may be read by the host computer 522 from one or more floppy disks, flexible disks, magnetic tapes, any other magnetic medium, CD-ROMs, any other optical medium, punchcards, papertape, or any other physical medium with patterns of holes, or any other medium from which a computer can read. In an alternative embodiment, the host computer 522 can access two or more databases 532 , stored in a variety of mediums, as previously discussed. Referring to FIG. 6, in an embodiment, each user station 524 and the host computer 522 , each referred to generally as a processing unit, embodies a general architecture 605 . A processing unit includes a bus 606 or other communication mechanism for communicating instructions, messages and data, collectively, information, and one or more processors 607 coupled with the bus 606 for processing information. A processing unit also includes a main memory 608 , such as a random access memory (RAM) or other dynamic storage device, coupled to the bus 606 for storing dynamic data and instructions to be executed by the processor(s) 607 . The main memory 608 also may be used for storing temporary data, i.e., variables, or other intermediate information during execution of instructions by the processor(s) 607 . A processing unit may further include a read only memory (ROM) 609 or other static storage device coupled to the bus 606 for storing static data and instructions for the processor(s) 607 . A storage device 610 , such as a magnetic disk or optical disk, may also be provided and coupled to the bus 606 for storing data and instructions for the processor(s) 607 . A processing unit may be coupled via the bus 606 to a display device 611 , such as, but not limited to, a cathode ray tube (CRT), for displaying information to a user. An input device 612 , including alphanumeric and other columns, is coupled to the bus 606 for communicating information and command selections to the processor(s) 607 . Another type of user input device may include a cursor control 613 , such as, but not limited to, a mouse, a trackball, a fingerpad, or cursor direction columns, for communicating direction information and command selections to the processor(s) 607 and for controlling cursor movement on the display 611 . According to one embodiment of the invention, the individual processing units perform specific operations by their respective processor(s) 607 executing one or more sequences of one or more instructions contained in the main memory 608 . Such instructions may be read into the main memory 608 from another computer-usable medium, such as the ROM 609 or the storage device 610 . Execution of the sequences of instructions contained in the main memory 608 causes the processor(s) 607 to perform the processes described herein. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement the invention. Thus, embodiments of the invention are not limited to any specific combination of hardware circuitry and/or software. The term “computer-usable medium,” as used herein, refers to any medium that provides information or is usable by the processor(s) 607 . Such a medium may take many forms, including, but not limited to, non-volatile, volatile and transmission media. Non-volatile media, i.e., media that can retain information in the absence of power, includes the ROM 609 . Volatile media, i.e., media that can not retain information in the absence of power, includes the main memory 608 . Transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise the bus 606 . Transmission media can also take the form of carrier waves; i.e., electromagnetic waves that can be modulated, as in frequency, amplitude or phase, to transmit information signals. Additionally, transmission media can take the form of acoustic or light waves, such as those generated during radio wave and infrared data communications. Common forms of computer-usable media include, for example: a floppy disk, flexible disk, hard disk, magnetic tape, any other magnetic medium, CD-ROM, any other optical medium, punchcards, papertape, any other physical medium with patterns of holes, RAM, ROM, PROM (i.e., programmable read only memory), EPROM (i.e., erasable programmable read only memory), including FLASH-EPROM, any other memory chip or cartridge, carrier waves, or any other medium from which a processor 607 can retrieve information. Various forms of computer-usable media may be involved in providing one or more sequences of one or more instructions to the processor(s) 607 for execution. The instructions received by the main memory 608 may optionally be stored on the storage device 610 , either before or after their execution by the processor(s) 607 . Each processing unit may also include a communication interface 614 coupled to the bus 606 . The communication interface 614 provides two-way communication between the respective user stations 624 and the host computer 622 . The communication interface 614 of a respective processing unit transmits and receives electrical, electromagnetic or optical signals that include data streams representing various types of information, including instructions, messages and data. A communication link 615 links a respective user station 624 and a host computer 622 . The communication link 615 may be a LAN 526 , in which case the communication interface 614 may be a LAN card. Alternatively, the communication link 615 may be a PSTN 528 , in which case the communication interface 614 may be an integrated services digital network (ISDN) card or a modem. Also, as a further alternative, the communication link 615 may be a wireless network 530 . A processing unit may transmit and receive messages, data, and instructions, including program, i.e., application, code, through its respective communication link 615 and communication interface 614 . Received program code may be executed by the respective processor(s) 607 as it is received, and/or stored in the storage device 610 , or other associated non-volatile media, for later execution. In this manner, a processing unit may receive messages, data and/or program code in the form of a carrier wave.

A method and system for determining when to collect, save, and/or utilize histograms is disclosed. A mechanism for automatically deciding when to collect histograms upon request from the user is provided. The histogram collection decision is based on the columns the user is interested in, the role these columns play in the queries as submitted to the system, and the underlying distribution for these columns, e.g., as seen in a random sample. The user specifies which columns are of interest, and the database is configured to collect column usage information that describes how each column is being used in the workload. This column usage information could be stored in memory and periodically flushed to disk. Given a set of potential columns, the distribution of those columns is viewed in combination with the usage information to determine which columns should have histograms.

CROSS-REFERENCE TO RELATED APPLICATION [0001] The present application claims priority to currently pending U.S. Provisional Application Ser. No. 61/050,406 that was filed on May 5, 2008 and entitled MATERIAL DISPENSING ASSEMBLY. The present application claims priority the above-identified provisional patent application, which is incorporated in its entirety herein by reference for all purposes. TECHNICAL FIELD [0002] The present disclosure relates to a material dispensing assembly, and more particularly, a material dispensing assembly for sausage or bag-type dispensing tools. BACKGROUND [0003] Dispensing tools have been available for a number of years, assisting in the application of material to a desired surface in residential, commercial, or manufacturing environments, Such materials include, for example, adhesives, lubricants, and sealants such as, silicone, urethanes, and caulk. Conventional dispensing tools frequently visualized are of the type of a handheld caulk gun 10 , as illustrated in FIG. 1 , Cartridges 12 shown in FIG. 2 having any number of different types of materials, including those listed above are inserted into a cartridge support sleeve 14 located on the top side of the dispensing tool 10 . A trigger 16 on the gun 10 when actuated drives a rack 18 having a plunger 20 that engages the material located in the cartridge 12 such that each actuation of the trigger, forces material to be dispensed from a nozzle 22 located at an end 24 of the cartridge. [0004] A more modern dispensing tool for applying various materials, including those materials listed above is a power dispensing gun 30 , having a battery, pneumatic, or other means for powering motor for portable use is illustrated in FIG. 3 . The power dispensing gun 30 is also capable of using the cartridges 12 filled with dispensing material by inserting the cartridges 12 into a support sleeve 32 located on the top of the power dispensing gun 30 . A trigger 34 on the power dispensing gun 30 is actuated, driving a rack 36 having a plunger 38 that engages the material located in the cartridge 12 such that each actuation of the trigger forces material to be dispensed from a nozzle 40 located at the end 42 of the gun. Further details of the operation and configuration of a power dispensing gun is explained in U.S. patent application Ser. No. 11/918,689 entitled POWERED DISPENSING TOOL AND METHOD FOR CONTROLLING SAME that is assigned to the assignee of the present invention and is incorporated herein by reference in its entirety for all purposes. [0005] Cartridges 12 are not the only form of container for holding material used by the dispensing guns 10 , 30 , but another known type of container is a sausage pack or bag-type container 50 shown in FIG. 4 . The sausage pack 50 includes a first and second ends 52 , 54 , respectively extending from a main body 56 having dispensing material therein. The sausage pack 50 is positioned in a housing tube 58 located on the guns 10 , 30 in place of the cartridge support sleeves 14 , 32 , respectively as illustrated in FIGS. 5 and 7 . The sausage pack 50 once inserted into the guns has an opening 60 (shown in phantom is typically formed from removal of a containment ring or by piercing the sausage pack) toward the nozzle 22 , 40 and the plunger 20 , 38 squeezes the material out the nozzle when the trigger 16 , 34 is engaged. [0006] One example of a dispensing tool having interchanging support sleeves includes U.S. patent application Ser. No. 11/973,242 filed on Oct. 5, 2007 entitled DISPENSING TOOL that is assigned to the assignee of the present invention and is incorporated herein by reference in its entirety for all purposes. The '242 application illustrates a system for interchanging support sleeves from a cartridge-type dispenser to a sausage pack dispenser and vice versa as desired by the operator on a single power dispenser. [0007] Sausage packs 50 are typically more economical because of their cheaper fabrication. As a result, the sausage packs 50 are typically used more frequently in high volume commercial and manufacturing operations over conventional cartridges 12 in material dispensing guns. SUMMARY [0008] One example embodiment of the present disclosure includes a material dispensing assembly for converting a portable cartridge dispensing tool to a bag-type dispensing tool. The assembly comprises a single piece piston for advancing material though a material housing. The single piece piston includes a substantially square-shaped receptacle. The assembly further comprises a square shaped drive rack for attaching to the piston at the substantially square-shaped receptacle at a connection end. The drive rack further comprises a plurality of teeth located thereon. The assembly further has a support with a substantially square profile for receiving and supporting the drive rack during operation such that the construct of the drive rack and piston are prevented from rotating during operation. [0009] Another example embodiment of the present disclosure includes a single-piece piston for advancing material in a dispensing gun. The piston comprises first and second ends, the first end having a dome profile with an annular taper extending outwardly toward the second end. The piston further comprises a circular seal lip integral with and extending about the perimeter of the piston, the circular seal lip includes a plurality of substantially equal segments located therebetween. A noncircular attachment aperture is located in the piston for attaching the piston to a dispensing gun. The noncircular attachment aperture in the piston prevents loosening and rotation of the piston during operation. [0010] A further example embodiment of the present disclosure includes a material dispensing gun assembly comprising a single piece piston for advancing material though a material housing. The single piece piston includes a substantially square-shaped receptacle for attaching the single piece piston to a dispensing gun and first and second ends. The first end includes an annular dome profile with first and second annular tapered surfaces extending outwardly toward the second end. The piston further comprises a circular seal lip integral and extending from the second annular tapered surface about the perimeter of the piston, the circular seal lip further comprises a plurality of substantially equal segments. The dispensing gun assembly also comprises a square shaped drive rack for attaching to the single-piece piston at the substantially square-shaped receptacle at a connection end and a plurality of teeth located thereon. The dispensing gun also includes a support having a substantially square profile for receiving and supporting the drive rack during operation such that the construct of the drive rack and piston are prevented from rotating during operation. [0011] A yet further example embodiment of the present disclosure includes a method of dispensing material from a material dispensing gun comprising loading a sausage bag comprising dispensing material into a tube removably attached to a dispensing gun, the tube having an exit end from which the dispensing material is dispensed during operation. The method also comprises locating the sausage bag between the exit end and a single piece piston in the tube and engaging the sausage bag with an annular dome located at a front end of the single piece piston located in the tube. The method further comprises advancing the single piece piston against the sausage bag with a rack fixedly attached to the single piece piston such that material located in the sausage bag engaged by the annular dome is dispensed from the exit end of the tube and unadvanced material not engaged by the annular dome extends over first and second tapered annular surfaces of the dome. The method also includes engaging the unadvanced material in the sausage bag with a circular seal lip integral and extending from the second annular tapered surface about the perimeter of the piston, the circular seal lip comprises a plurality of substantially equal segments located about the perimeter of the circular seal lip and advancing the unadvanced material with the plurality of substantially equal segments of the single piece piston such that the unadvanced material located in the sausage bag engaged by the plurality of segments is dispensed from the exit end of the tube. [0012] Another example embodiment of the present disclosure includes a material dispensing housing for use with bag-type dispensing material. The material dispensing housing comprises a transparent tube for supporting bag-type dispensing material, the tube is formed from high-temperature resistant polymeric material. The transparent tube allows for the visualization of the movement of dispensing material located within the housing during operation. The housing also comprises a base coating selected from one of a silicone coating and polysiloxane coating. The base coating provides superior service life and reduced friction of the bag holding the dispensing material and reduces the friction with a piston that engages the tube and the bag-type dispensing material during operation. BRIEF DESCRIPTION OF THE DRAWINGS [0013] The foregoing and other features and advantages of the present invention will become apparent to one skilled in the art to which the present invention relates upon consideration of the following description of the invention with reference to the accompanying drawings, wherein like reference numerals refer to like parts throughout the drawings and in which: [0014] FIG. 1 is a side elevation view of a manual dispensing gun adapted for a cartridge-type material container; [0015] FIG. 2 is a side cross sectional elevation view of a cartridge-type material container for use in a manual or powered dispensing gun; [0016] FIG. 3 is a side elevation view of a power dispensing gun adapted for a cartridge-type material container; [0017] FIG. 4 is a side elevation view of a sausage pack material container for use in a manual or powered dispensing gun; [0018] FIG. 5 is a perspective view of a tube for housing a sausage pack material container of FIG. 4 ; [0019] FIG. 6 is an exploded assembly view of a material dispensing assembly adapted for a power dispensing tool constructed in accordance with one embodiment of the present disclosure; [0020] FIG. 7 is a side view of a power dispensing gun adapted to support the material dispensing assembly of FIG. 6 ; [0021] FIG. 8A is a rear isometric view of a single piece piston constructed in accordance with one embodiment of the present disclosure; [0022] FIG. 8B is a front isometric view of the single piece piston constructed in accordance with the example embodiment of FIG. 8A ; [0023] FIG. 8C is a rear elevation view of the single piece piston constructed in accordance with the example embodiment of FIG. 8A ; [0024] FIG. 8D is a side elevation view of the single piece piston constructed in accordance with the example embodiment of FIG. 8A ; [0025] FIG. 8E is a front elevation view of the single piece piston constructed in accordance with the example embodiment of FIG. 8A ; [0026] FIG. 8F is a cross-section elevation side view of the single piece piston constructed in accordance with the example embodiment of FIG. 8A ; and [0027] FIG. 8G is a magnified view of a portion of the single piece piston cross-section identified in the example embodiment of FIG. 8G . DETAILED DESCRIPTION [0028] The present disclosure relates to a material dispensing assembly 100 , and more particularly, a material dispensing assembly for easily converting portable cartridge dispensing tools to sausage or bag-type dispensing tools. One example embodiment of the material dispensing assembly 100 is illustrated in FIG. 6 . The assembly 100 can be adapted to convert a power dispensing tool from the cartridge-type dispenser illustrated in FIG. 3 to that of a sausage type dispenser as illustrated in the example embodiment of the power dispensing tool 102 in FIG. 7 that can be powered by battery, pneumatic means, and the like. [0029] The power dispensing assembly 100 of FIG. 6 comprises a sausage holding tube 104 having first and second ends 106 , 108 , respectively. A sausage pack 50 of various lengths is installed through the first end 106 and material within the sausage pack is forced out by a piston 110 that is located behind the sausage pack in the second end 108 during operation. The material that is dispensed from the sausage pack 50 could include caulk, adhesives, silicone, urethanes, and the like without departing from the spirit and scope of the claimed invention. The piston 110 is advanced by a square piston rack 112 , which forces the piston against the sausage pack 50 , forcing material to dispense from the first end 106 through a nozzle 114 that is retained to the tube 104 by a cap 116 via a threaded connection 117 . [0030] The amount and speed of the material dispensed from the sausage pack 50 by the piston 110 could be a function of the speed of the motor (internal to the gun), or the extent of travel by the piston in the tube 104 . For example, the piston 110 could “bottom-out” against an empty sausage pack 50 that is compressed against the cap 116 and nozzle 114 . The rack 112 moveably passes through components internal to the gun 102 , including a pinion gear 118 (that engages and drives the rack in both forward and reverse directions) coupled to a gear set 120 driven in both a forward and reverse direction by a motor 122 . The positioning of the gear set 120 and pinion gear 118 in combination with supports 124 internal to the gun 102 , fix the orientation of the rack 112 through its path of travel when advancing and reversing the piston. 110 in the tube 104 . The supports 124 comprise square shaped bushings, guides, or fixtures that maintain the orientation of the rack 112 to prevent rotation of the rack or piston 110 during operation. [0031] The rack 112 includes first 126 and second 128 ends. The first end 126 passes through a barrel screw 127 , spacer 130 , end cap 132 , and washer 134 . The barrel screw 127 couples the dispensing assembly 100 through the spacer 130 and end cap 132 to a mating threaded connection 133 located in a housing porting 135 of the gun 102 for engagement with the barrel screw. Attached to the first end 126 of the rack 112 is a rack handle 136 for assisting in the reloading and unloading of the sausage packs 50 from the tube 104 . The rack handle 136 is secured to a threaded aperture located in the first end 126 of rack by a screw 138 . [0032] The first and second ends 106 , and 108 , respectively have respective threaded sections 106 A and 108 A. The first threaded section 106 A co-acts with internal threads 116 A associated with cap 116 and secures the cap to the first end 106 of the tube 104 , locking the nozzle 114 between the tube and cap at the first end. The second threaded section 108 A co-acts with internal threads 132 A associated with end cap 132 . Once the end cap 132 is secured to the housing 135 of the dispensing gun 102 , as described above, the second threaded second 108 A is screwed into the end cap, thereby supporting the tube 104 to the housing. [0033] Plungers 20 used in conventional dispensing guns (see FIG. 1 ), are commonly threaded on the end of a drive rack 18 . Tightening the plunger 20 to the rack and applying a lock-nut is a typical means of securing the plunger. As some cartridges 12 and their corresponding support sleeves are designed to be rotated, the tendency to have the plunger 20 “unscrew” from the drive rack is appreciable, especially during operations when the user is attempting to turn the cartridge 12 while there is axial pressure being applied to the drive rack. [0034] Such problems are resolved by one embodiment of the present invention. In particular, the rack 112 comprises a square configuration to be received and attached to a corresponding a square receptacle 140 in the piston 110 , as illustrated in FIGS. 8A , 8 C, and 8 F. The rack 112 engages the receptacle until it is in contact with an internal face 141 in the piston 110 and is secured to the piston by a fastener 143 that passes through an opening 165 into a counter-bore 167 , for seating the fastener during attachment. Such design and the corresponding square supports 124 internal to the gun 102 prevent rotation of the rack 112 and preclude any loosening of the piston 110 . [0035] The rack 112 construction in the illustrated embodiment of FIG. 6 provides yet another advantage from the present disclosure. The square piston 110 , corresponding square receptacle 140 , and rack 112 allow the rack to be reversed such that the first end 126 can be flipped with the second end 128 . This reversible rack 112 feature is advantageous when the rack becomes worn by the pinion gear 118 along an advanced direction (see arrow A in FIG. 6 ). At such time that the rack 112 shows signs of wear, the mirror image construction and corresponding attachments allow the rack to be flipped 180 degrees between the first and second ends 126 , 128 while remaining in the same orientation as shown in FIG. 6 . The pinion 118 now drives unworn teeth 142 in the advanced direction “A”. The fasteners 138 , 143 and receiving threaded connections in the rack 112 at first and second ends 126 , 128 are the same, allowing the piston 110 and rack handle 136 to be reversed, extending the life of the rack as discussed above. [0036] The piston 110 provides several advantages illustrated in the exemplary embodiment of FIGS. 6 and 8 . While conventional plungers 20 are typically configured from multiple pieces, the piston 110 is a single uniform piece made from a single molding operation. This eliminates both material and assembly costs experienced in conventional plunger designs. While the piston 110 can be made from any number of suitable polymeric materials, the construct of the piston in the example embodiment is formed from Nylon 66 material. The polymeric material of the piston 110 advantageously weighs less than one ounce, while compared to conventional plungers that weigh much more and up to eight ounces. The reduction in weight in the exemplary embodiment of the single piece piston 110 reduces stress, strain, and other ergonomic issues typically experienced in wrists and arms of operators using conventional dispensing guns. [0037] The piston 110 comprises front 144 and back 146 ends as shown in FIGS. 8B and 8D , an annular dome 148 , and circular lip portion 150 , as shown in FIG. 8C . The construct of the annular dome 148 at the front 144 of the piston 110 is designed to extrude the maximum amount of material from the tube 104 and sausage packet 50 therein. In particular, the dome 148 comprises a first tapered annular surface 151 , raising the unadvanced material in the sausage packet 50 up over the tapered annular face to a plurality of segmented sections 152 integrated into the dome and extending from the single piece piston 110 . In the illustrated embodiment, twelve (12) segmented sections represented by 152 A- 152 L (see FIG. 8E ) in the circular lip portion 150 capture and advance forward the remaining material in the sausage packet 50 as the piston 110 advances through the tube 104 . While twelve segmented sections 152 are shown in the illustrated embodiment of FIG. 8 , more or less segmented sections could be used without departing from the spirit and scope of the claimed invention. [0038] The independent flexibility achieved by the segmented sections 152 A- 152 L provide a heightened ability to facilitate a solid lip seal to a tube 104 or cartridge 12 internal wall under varying roundness tolerances especially experienced in cartridge tubes. Further the specific piston 110 diameter, piston lip geometry, including thickness, taper, and edge angles provide dispensing free of “bag wrap” failures, while enabling a low “pull back” force in sausage-type applications. In addition, the piston 110 design provides a low drag force in the forward direction (see arrow A in FIG. 6 ), enabling greater dispensing forces to be achieved. In the illustrated embodiment of FIGS. 8A-8G , the lip thickness represented by dimension “A” in FIG. 8G is approximately 0.34 inches, having a front taper 162 of approximately 6 degrees represented by dimension “B”, and edge angle off a rear edge 160 of each segmented sections 152 of approximately 15 degrees represented by dimension “C”, and a back angle off a second tapered annular surface 163 on the dome 151 of approximately 92 degrees represented by dimension “D”, as illustrated in FIGS. 8F and 8G . [0039] The twelve segmented sections 152 A- 152 L are capable under the current embodiment of FIG. 8 of independently undulating to maintain substantially constant regulated pressure to the sausage pack 50 , preventing bag wrap failures where the bag of the sausage pack 50 would pinch between the plunger and tube in conventional plunger designs. In the exemplary embodiment of FIGS. 8A-8G , a vent spacing 154 is provided between the 12 segmented sections 152 A- 152 L of approximately 0.030 inches represented by dimension “X” in FIG. 8E . The overall length of the piston is approximately 1 inch represented by dimension “E” in FIG. 8D and the overall diameter of the piston 110 in the illustrated embodiment of FIG. 8 is approximately 2.0 inches as illustrated in FIG. 8E by dimension “F”, and the segmented sections extend from the dome 151 outward at approximately 0.69 inch diameter radius from the center “O” of the piston. It should be appreciated however, that proportionally larger and smaller dimensions would be required for larger and smaller diameter tubes and are intended to be covered by the spirit and scope of the claimed invention. [0040] The vent spacings 154 in addition to providing independent pressure to the inner diameter of the tube 104 and/or sausage pack 50 , allow air to escape from the tube when the sausage pack is being inserted or removed. This allows for easier replacement and removal of sausage packs 50 during operation by the user. The piston 110 also comprises a number of voids on the back end 146 . The voids 155 improve the overall structural strength and facilitate a reduction in the weight of the piston 110 . [0041] The tube 104 in one exemplary embodiment is transparent so that the material dispensed from the sausage pack 50 can be observed and visually measured by the user. In addition, the transparent tube 104 allows the user to visually inspect the tube while performing a cleaning operation. [0042] In another example embodiment, the tube 104 is transparent (i.e. clear and chemical resistant) and made from an a high temperature annealed polycarbonate or polyamide based material 82 and lined with a based coating 84 , allowing superior service life in a demanding environment of repeated stress, thermal, and chemical attack. Examples of suitable base coatings include silicone or polysiloxane. Such construction also reduces friction with the piston 110 and sausage bag 50 and reduces the force necessary for dispensing the material from the dispensing gun 102 . The base coatings 84 can be applied to the tube 104 by direct application, such as spraying or wiping the internal portions of the tube, through a heat treatment application process, or by extruding or impregnating the base material 82 with the base coating material during the forming of the base material. [0043] What have been described above are examples of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. For example, while the material dispensing assembly was illustrated being adapted to a power dispensing gun, it could equally be adapted to a manual dispensing gun without departing from the spirit or scope of the claimed invention. Accordingly, the present invention is intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.

A material dispensing assembly ( 100 ) and method of operation is disclosed for converting a portable cartridge dispensing tool to a bag-type dispensing tool. The assembly comprises a single piece piston ( 110 ) for advancing material though a material housing ( 104 ), the single piece piston ( 110 ) includes a substantially square-shaped receptacle ( 140 ). The assembly further comprises a square shaped drive rack ( 112 ) for attaching to the piston ( 110 ) at the substantially square-shaped receptacle ( 140 ) at a connection end ( 128 ). The drive rack ( 112 ) further comprises a plurality of teeth ( 142 ) located thereon. The assembly ( 100 ) further has a support ( 127 ) with a substantially square profile for receiving and supporting the drive rack ( 112 ) during operation such that the construct of the drive rack and piston ( 110 ) are prevented from rotating during operation.

BACKGROUND OF THE INVENTION Field of the Invention The invention relates to processing an audio signal. Spatial processing, also known as 3D audio processing, applies various processing techniques in order to create a virtual sound source (or sources) that appears to be in a certain position in the space around a listener. Spatial processing can take one or many monophonic sound streams as input and produce a stereophonic (two-channel) output sound stream that can be reproduced using headphones or loudspeakers, for example. Typical spatial processing includes the generation of interaural time and level differences (ITD and ILD) to output signal caused by head geometry. Spectral cues caused by human pinnae are also important because the human auditory system uses this information to determine whether the sound source is in front of or behind the listener. The elevation of the source can also be determined from the spectral cues. Spatial processing has been widely used in e.g. various home entertainment systems, such as game systems and home audio systems. In telecommunication systems, such as mobile telecommunications systems, spatial processing can be used e.g. for virtual mobile teleconferencing applications or for monitoring and controlling purposes. An example of such a system is presented in WO 00/67502. In a typical mobile communications system the audio (e.g. speech) signal is sampled at a relatively low frequency, e.g. 8 kHz, and subsequently coded with a speech codec. As a result, the regenerated audio signal is bandlimited by the sampling rate. If the sampling frequency is e.g. 8 kHz, the resulting signal does not contain information above 4 kHz. The lack of high frequencies in the audio signal, in turn, is a problem if spatial processing is to be applied to the signal. This is due to the fact that a person listening to a sound source needs a signal content of a high frequency (the frequency range above 4 kHz) to be able to distinguish whether the source is in front of or behind him/her. High frequency information is also required to perceive sound source elevation from 0 degree level. Thus, if the audio signal is limited to frequencies below 4 kHz, for example, it is difficult or impossible to produce a spatial effect on the audio signal. One solution to the above problem is to use a higher sampling rate when the audio signal is sampled and thus increase the high frequency content of the signal. Applying higher sampling rates in telecommunications systems is not, however, always feasible because it results in much higher data rates with increased processing and memory load and it may also require designing a new set of speech coders, for example. BRIEF DESCRIPTION OF THE INVENTION An object of the present invention is thus to provide a method and an apparatus for implementing the method so as to overcome the above problem or to at least alleviate the above disadvantages. The object of the invention is achieved by providing a method for processing an audio signal, the method comprising receiving an audio signal having a narrow bandwidth; expanding the bandwidth of the audio signal; and processing the expanded bandwidth audio signal for spatial reproduction. The object of the invention is also achieved by providing an arrangement for processing an audio signal, the arrangement comprising means for expanding the bandwidth of an audio signal having a narrow bandwidth; and means for processing the expanded bandwidth audio signal for spatial reproduction. Furthermore, the object of the invention is achieved by providing an arrangement for processing an audio signal, the arrangement comprising bandwidth expansion means configured to expand the bandwidth of an audio signal having a narrow bandwidth; and spatial processing means configured to process the expanded bandwidth audio signal for spatial reproduction. The invention is based on an idea of enhancing spatial processing of a low-bandwidth audio signal by artificially expanding the bandwidth of the signal, i.e. by creating a signal with higher bandwidth, before the spatial processing. An advantage of the method and arrangement of the invention is that the proposed method and arrangement are readily compatible with existing telecommunications systems, thereby enabling the introduction of high quality spatial processing to current low-bandwidth systems with only relatively minor modifications and, consequently, low cost. Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which FIG. 1 is a block diagram of a signal processing arrangement according to an embodiment of the invention; and FIG. 2 is a block diagram of a signal processing arrangement according to an embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION In the following the invention is described in connection with a telecommunications system, such as a mobile telecommunications system. The invention is not, however, limited to any particular system but can be used in various telecommunications, entertainment and other systems, whether digital or analogue. A person skilled in the art can apply the instructions to other systems containing corresponding characteristics. FIG. 1 illustrates a block diagram of a signal processing arrangement according to an embodiment of the invention. It should be noted that the figures only show elements that are necessary for the understanding of the invention. The detailed structure and functions of the system elements are not shown in detail, because they are considered obvious to a person skilled in the art. According to the invention, a low-bandwidth (or narrow bandwidth) audio signal, e.g. speech signal, is first processed in order to expand the bandwidth of the audio signal; this takes place in a bandwidth expansion block 20 . The obtained high-bandwidth (or expanded bandwidth) audio signal is then further processed for spatial reproduction; this takes place in a spatial processing block 30 , which preferably produces a stereophonic binaural audio signal. The low-bandwidth audio signal can be obtained e.g. from a transmission path of a telecommunications system via an audio decoder, such as a speech decoder 10 , if the audio signal is transmitted in a coded form. However, the source of the low-bandwidth audio signal received at block 20 is not relevant to the basic idea of the invention. Furthermore, the terms ‘low-bandwidth’ or ‘narrow bandwidth’ and ‘high-bandwidth’ or ‘expanded bandwidth’ should be understood as descriptive and not limited to any exact frequency values. Generally the terms ‘low-bandwidth’ or ‘narrow bandwidth’ refer approximately to frequencies below 4 kHz and the terms ‘high-bandwidth’ or ‘expanded bandwidth’ refer approximately to frequencies over 4 kHz. The invention and the blocks 10 , 20 and 30 can be implemented by a digital signal processing equipment, such as a general purpose digital signal processor (DSP), with suitable software therein, for example. It is also possible to use a specific integrated circuit or circuits, or corresponding devices. The input for the speech decoder 10 is typically a coded speech bitstream. Typical speech coders in telecommunication systems are based on the linear predictive coding (LPC) model. In LPC-based speech coding the voiced speech is modeled by filtering excitation pulses with a linear prediction filter. Noise is used as the excitation for unvoiced speech. Popular CELP (Codebook Excited Linear Prediction) and ACELP (Algebraic Codebook Excited Linear Prediction)-coders are variations of this basic scheme in which the excitation pulse(s) is calculated using a codebook that may have a special structure. Codebook and filter coefficient parameters are transmitted to the decoder in a telecommunication system. The decoder 10 synthesizes the speech signal by filtering the excitation with an LPC filter. Some of the more recent speech coding systems also exploit the fact that one speech frame seldom consists of purely voiced or unvoiced speech but more often of a mixture of both. Thus, it is purposeful to make separate voiced/unvoiced decisions for different frequency bands and that way increase the coding gain. MBE (Multi-Band Excitation) and MELP (Mixed Excitation Linear Prediction) use this approach. On the other hand, codecs using Sinusoidal or WI (Waveform Interpolation) techniques are based on more general views on the information theory and the classic speech coding model with voiced/unvoiced decisions is not necessarily included in those as such. Regardless of the speech coder used, the resulting regenerated speech signal is bandlimited by the original sampling rate (typically 8 kHz) and by the modeling process itself. The lowpass style spectrum of voiced phonemes usually contains a clear set of resonances generated by the all-pole linear prediction filter. The spectrum for unvoiced speech has a high-pass nature and contains typically more energy in the higher frequencies. The purpose of the bandwidth expansion block 20 is to artificially create a frequency content on the frequency band (approximately >4 kHz) that does not contain any information and thus enhance the spatial positioning accuracy. Studies show that higher frequency bands are important in front/back and up/down sound localization. It seems that frequency bands around 6 kHz and 8 kHz are important for up/down localization, while 10 kHz and 12 kHz bands for front/back localization. It must be noted that the results depend on subject, but as a general conclusion it can be said that the frequency range of 4 to 10 kHz is important to the human auditory system when it determines sound location. If the bandwidth expansion block 20 is designed to boost these frequency bands, for example 6 kHz and 8 kHz, it is likely that the up/down accuracy of spatial sound source positioning can be increased for an originally bandlimited signal (for example a coded speech that is bandlimited to below 4 kHz). The bandwidth expansion block 20 can be implemented by using a so-called AWB (Artificial WideBand) technique. The AWB concept is originally developed for enhancing the reproduction of unvoiced sounds after low bit rate speech coding and although there are various methods available the invention is not restricted to any specific one. Many AWB techniques rely on the correlation between low and high frequency bands and use some kind of codebook or other mapping technique to create the upper band with the help of an already existing lower one. It is also possible to combine intelligent aliasing filter solutions with a common upsampling filter. Examples of suitable AWB techniques that can be used in the implementation of the present invention are disclosed in U.S. Pat. Nos. 5,455,888, 5,581,652 and 5,978,759, incorporated herein as a reference. The only possible restriction is that the bandwidth expansion algorithm should preferably be controllable, because it is recommended to process unvoiced and voiced speech differently, therefore some kind of knowledge about the current phoneme class must be available. In the embodiment of the invention shown in FIG. 1 , the control information is provided by the speech decoder 10 . It is also useful for optimal speech quality that the expansion method is tunable to various speech codecs and spatial processing algorithms. However this property is not necessary. Output from the expansion block 20 is preferably an audio signal with artificially generated frequency content in frequencies above half the original sampling rate (Nyquist frequency). It should be noted that if the invention is realized with a digital signal processing apparatus and the signals are digital signals, the output signal has a higher sampling rate than the low-bandwidth input signal. The spatial processing block 30 can apply various processing techniques to create a virtual sound source (or sources) that appears to be in a certain position around a listener. The spatial processing block 30 can take one or several monophonic sound streams as an input and it preferably produces one stereophonic (two-channel) output sound stream that can be reproduced using either headphones or loudspeakers, for example. More than two channels can also be used. When creating virtual sound sources, the spatial processing 30 preferably tries to generate three main cues for the audio signal. These cues are: 1) Interaural time difference (ITD) caused by the different length of the audio path to the listener's left and right ear, 2) Interaural level difference (ILD) caused by the shadowing effect of the head, and 3) signal spectrum reshaping caused by the human head, torso and pinnae. The spectral cues caused by human pinnae are important because the human auditory system uses this information to determine whether the sound source is in front of or behind the listener. The elevation of the source can be also determined from the spectral cues. Especially the frequency range above 4 kHz contains important information to distinguish between the up/down and front/back directions. Generation of all these cues is often combined in one filtering operation and these filters are called HRTF-filters (Head Related Transfer Function). The reproduction of the spatialized audio signal can be done either with headphones, two-loudspeaker system or multichannel loudspeaker system, for example. When headphone reproduction is used, problems often arise when the listener is trying to locate the signal in front/back and up/down positions. The reason for this is that when the sound source is located anywhere in the vertical plane intersecting the midpoint of the listener's head (median plane), the ILD and ITD values are the same and only spectral cues are left to determine the source position. If the signal has only little information on the frequency bands that the human auditory system uses to distinguish between front/back and up/down, then the location of the signal is very difficult. The design and parameter selection of bandwidth expansion can affect the spatial processing block and vice versa, when the system and its properties are being optimized. Generally speaking, the more information there is above the 4 kHz frequency range, the better the spatial effect. On the other hand, overamplified higher frequencies can, for example, degrade the perceived speech quality as far as speech naturalness is concerned, whereas speech intelligibility as such may still improve. The properties of the bandwidth expansion block 20 can be taken into account when designing HRTF filters generally used to implement spectral and ILD cues. Some frequency bands can be amplified and others attenuated. These interrelations are not crucial but can be utilized when optimizing the invention. There is also another interrelation between the bandwidth expansion 20 and the spatial processing 30 . The HRTF filters that are preferably used for the spatial processing typically emphasize certain frequency bands and attenuate others. To enable real-time implementations these filters should preferably not be computationally too complex. This may set limitations on how well a certain filter frequency response is able to approximate peaks and valleys in the targeted HRTF. If it is known that the bandwidth expansion 20 boosts certain frequency bands, the limited amount of available poles and zeros can be used in other frequency bands, which results to a better total approximation, when the combined frequency response of the bandwidth expansion 20 and the spatial processing 30 is considered. Therefore, the bandwidth expansion 20 and the spatial processing 30 may be jointly optimized to reduce and re-distribute the total or partial processing load of the system, relating to e.g. the expansion 20 or the spatial processing 30 . The bandwidth expansion 20 may, for example, shape the spectrum of the bandwidth expanded audio signal in such a way that it further enhances the spatial effect achieved with the HRTF filter of limited complexity. This approach is especially attractive when said spectrum shaping can be done by simple weighting, possibly simply by adjusting the weighting coefficients or other related parameters. If the existing bandwidth expansion process 20 already comprises some kind of frequency weighting, additional modifications necessary for supporting the specific requirements of the spatial processing 30 may be practically non-existent, or at least modest. Additionally, aforementioned techniques can be applied in a multiprocessor system that runs the bandwidth expansion 20 in one processor and the spatial processing 30 in another, for example. The processing load of the spatial audio processor may be reduced by transferring computations to the bandwidth expansion processor and vice versa. Furthermore, it is possible to dynamically distribute and balance the overall load between the two processors for example according to the processing resources available for the bandwidth expansion 20 and/or spatial processing 30 . FIG. 2 illustrates a block diagram of a signal processing arrangement according to another embodiment of the invention. In the illustrated alternative embodiment, no control information is provided from the speech decoder 10 to the artificial bandwidth expansion block 20 . Instead, the control information is provided by an additional voice activity detector (VAD) 40 . It should be noted that the VAD block 40 can be integrated into the bandwidth expansion block 20 although in the figure it has been illustrated as a separate element. The system can also be implemented without any interrelations between the various processing blocks. According to an embodiment of the invention the audio decoder 10 is a general audio decoder. In this embodiment of the invention the implementation of the bandwidth expansion block 20 can be different than what is described above. A possible application for this embodiment of the invention is an arrangement in which the coded audio signal is provided by a low-bandwidth music player, for instance. It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

A processor for processing an audio signal can have a receiving unit configured to receive an audio signal, an expansion unit configured to expand a bandwidth of the audio signal, and a processing unit configured to process the audio signal having an expanded bandwidth for spatial reproduction.

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation in part of U.S. patent application Ser. No. 12/586,545 filed on Sep. 23, 2009 and claims the benefit of U.S. provisional patent application filed on Sep. 23, 2008. BACKGROUND OF THE INVENTION [0002] This invention concerns ropes or lines as they are called on a boat, and more particularly securing ropes or lines to hold a load, moor a boat, tighten a guy line for a tent, etc. Traditionally, knots have been tied into the rope or line to form a loop but this is time consuming to tie and untie, and also requires a good knowledge of the proper knot for a given purpose. [0003] While rope or wire clamping devices have been devised, these are not particularly suited to nautical application and are themselves sometimes inconvenient to clamp or release. [0004] An object of the present invention to provide a simple but durable and weatherproof device for quickly securing two rope or segments of a rope together or releasing the same which is suitable for boating applications but also for a wide variety of other purposes. SUMMARY OF THE INVENTION [0005] The above recited object as well as other objects which will be apparent upon a reading of the following specification and claims are achieved by a rope or line clamping device comprised of two generally tubular rotary members snap fit together to be securely held assembled to each other while being relatively rotatable to each other about a common axis. The members are preferably molded from a tough plastic material. Each member is formed with a radially extending internal web or wall which are juxtaposed next to each other. Each web has one or two holes formed therein, the holes each being elongated such as of an oval shape and located at a location radially offset from the rotary axis of the members. [0006] In one rotated position of the two members, the elongated holes are aligned with each other. The rope or line segments are inserted therein with the members then relatively rotated causing the holes to become increasingly offset with respect to each other, to in turn cause the size of a through opening defined by the overlapped areas of the holes to become progressively reduced. [0007] This allows a clamping action to be carried out by edges of the two holes which compress the rope segments passed through both holes. [0008] A ratcheting mechanism securely holds each of the members in relatively rotated position to prevent loosening once the rope segments have been clamped together. [0009] A ratchet pawl on one member is radially deflectable inwardly to overrun in one rotational direction in which clamping is carried only and, by the grip of the user to selectively move teeth on a element out of engagement with ratchet teeth formed extending at least partially around the perimeter of the other member, allowing reverse releasing rotation between the two members as long as the pawl is held in its released position. [0010] The pawl element is preferably integrally formed with the one member when molded and is moved radially by bending of a connecting leg within an opening in the one member. [0011] An additional hole can be provided in each member to provide two smaller holes in each web which are caused to be simultaneously increasingly offset when the members are relatively rotated. The smaller sized holes will clamp to individual smaller rope diameters to allow use with a greater range of rope sizes. DESCRIPTION OF THE DRAWING FIGURES [0012] FIG. 1 is a side view of a clamping device according to the invention showing rope segments clamped together therein. [0013] FIG. 2 is an enlarged pictorial view from the top of an outer member forming a part of the clamping device shown in FIG. 1 , the outer member inverted from its position in FIG. 1 . [0014] FIG. 3 is a pictorial view from the bottom of the inner member forming a part of the rope clamping device shown in FIG. 1 . [0015] FIG. 4 is a top view of the clamping device shown in FIG. 1 in the fully open relative rotated position of the members. [0016] FIG. 5 is a top view of the clamping device shown in FIG. 4 with the inner and outer members relatively rotated 180° to the minimum through opening position. [0017] FIG. 6 is a top view of the clamping device as shown in FIG. 4 but with the outer member shown in phantom lines. [0018] FIG. 7 is a top view of the clamping device as shown in FIG. 6 but rotatably advanced to the minimum through opening clamping position. [0019] FIG. 8 is a top view as shown in FIG. 6 but with rope segments disposed therein and rotated to an intermediate clamping position. [0020] FIG. 9 is a fragmentary top view of the clamping device as shown in FIG. 8 , but with the pawl element depressed to be disengaged from the ratchet teeth on the inner member. [0021] FIG. 10 is an enlarged fragmentary sectional view through a portion of the assembled inner and outer members. [0022] FIG. 11 is a top or end view of a second embodiment of a clamping device according to the invention, having two holes in a web of each member, shown in their aligned position. [0023] FIG. 12 is a top or end view of the clamping device shown in FIG. 11 with the members rotated to offset both holes in each member. DETAILED DESCRIPTION [0024] In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims. [0025] Referring to the drawings and FIGS. 1-3 , the rope or line clamping device 10 receives two segments of a rope 12 passing through the device 10 , the rope doubled over to form a loop and are clamped together by limited relative rotation of two members assembled together, for convenient reference referred to as an outer member 14 and an inner member 16 . [0026] The outer member 14 has a ribbed rim 18 for convenient gripping, while the smaller diameter tubular body 20 of the inner member 16 is longer and ribbed also for a convenient gripping. [0027] The outer member 14 also has a smaller diameter tubular body 22 . [0028] Both bodies 20 and 22 have an internal web or wall 24 , 26 extending across the inside diameter thereof. Each web 24 , 26 has a hole 28 , 30 formed therein which are preferably of an elongated shape such as the oval shape shown. [0029] The holes 28 , 30 are both located offset from the center axis of the bodies by preferably the same distance and preferably are of the same shape so that in one relative position of the members 14 , 16 , the holes 28 , 30 are aligned with each other. [0030] This defines the maximum area through opening defined by the overlapped areas of the two holes 28 , 30 and through which the two rope segments 12 A, 12 B of the rope 12 are inserted. [0031] When the two members are relatively rotated, as while gripping the ribbed rim 18 and body 20 in each hand, the holes 28 , 30 become misaligned to a progressively greater extent, as seen in FIGS. 8 and 9 to reduce the area of overlap and thus to reduce the size of the through opening. This causes the edges of the holes 28 , 30 to compress against the two rope segments 12 A, 12 B clamping them together. The thickness of the webs 24 , 26 is sufficient as to not cut into the rope while creating sufficient pressure to securely engage the same, i.e., about an ⅛ inch thickness has been found to be satisfactory for this purpose. [0032] The two members 14 , 16 are preferably molded using a high strength plastic, such as 67% nylon filled with 33% fiberglass fibers. A UV protection additive is also desirable. [0033] The two members 14 , 16 have an internal ratchet mechanism described below which secures the two members 14 , 16 in each advanced rotative position when rotated in one direction (clockwise in the Figures) from the fully open position shown in FIG. 4 . The ratchet mechanism is able to be released by pushing on a release button 32 projecting beyond the rim 18 of the outer remember 14 . [0034] The body 20 of the inner member 16 has a slightly larger diameter rim 34 which projects above the internal web 26 and is formed for about half its inner surface with a series of internal ratchet teeth 36 which are shaped to mate with several ratchet teeth 38 facing out on a pawl 40 connected to the button 32 . [0035] The pawl 40 is molded integrally with the outer member 14 but fit within a recess 42 formed in the rim 18 , the body 22 and web 24 , cantilevered on the end of a leg 44 projecting axially from the body 22 adjacent the upper side of the recess 42 . The leg 44 is thick enough (about 3/16 inches) and short enough to hold the ratchet teeth 36 , 38 firmly in engagement, but still allow the pawl 40 to be deflected radially inward sufficiently to disengage the teeth 36 , 38 when compressed by the user's grip allowing relative opening rotation of members 14 , 16 , and also to allow the ratchet teeth 36 , 38 to overrun each other when relatively rotating the member 14 , 16 in the clamping direction. [0036] The inside diameter 19 of the rim 18 is formed with a groove 46 at the bottom of the rim 18 . The groove 46 extends around to either side of a clearance space 48 formed between the ratchet button 32 and pawl 40 . [0037] This clearance enables the rim 34 to rotate through while allowing engagement of the ratchet teeth 36 and 38 . [0038] The two members 14 and 16 are snap fit together to partially overlap each other with the rim 34 (which is chamfered to make fitting easier) inserted into the inside diameter 19 . [0039] A series of spaced sloping shallow features 50 interact with the rim chamfer to enable the rim 34 to be compressed slightly and also expand the rim 18 during insertion until passing over the features 50 . Thereafter, the rims 34 , 18 snap back to their unstrained dimensions to be captured above the features 50 , and the members 14 , 16 are held together with assembly but able to relatively rotate to a limited extent as will be described below. In order to facilitate expansion of the rim 18 during assembly, a series of spaced windows 52 are formed therein around the perimeter thereof. [0040] The relative rotation between the members 14 , 16 is limited to about one half turn by an axially projecting tab 54 integral with the rim 34 . The tab 54 rides in the groove 46 where it is deepest. The groove 46 has a segment 46 A beyond the adjacent windows on either side of the pawl 40 which is shallower such that the tab 54 prevents relative rotation in either direction past the deep section of the groove 46 . [0041] This prevents relative rotary movement of the members 14 , 16 past the full open position in a counterclockwise direction (shown in FIG. 6 ) or past the most advanced clamped position in a clockwise direction (shown in FIG. 7 ). [0042] Another tab 56 projects radially from the perimeter of the hole 30 at its midpoint. This tends to engage and move the rope segments 12 A to a long ways juxtaposition within the holes 28 , 30 as seen in FIG. 8 to insure a strong grip is achieved. [0043] In use, the members 14 , 16 are rotated to the fully open position seen in FIGS. 4 and 6 . [0044] After insertion of the rope segments into the through opening defined through the holes 28 , 30 , the members 14 , 16 are relatively rotated in a clockwise direction to reduce the through opening size by progressive misalignment of the holes 28 , 30 until the rope segments are tightly compressed by the hole edges as seen in FIG. 7 or 8 . Different size ropes can be clamped within a predetermined range by greater or lesser rotation of members 14 , 16 . [0045] The ratchet teeth 36 , 38 override when the members 14 , 16 are relatively rotated in that direction but immediately lock together upon release of the members preventing any attempted counter rotation so that the members 14 , 16 are held locked together with the rope segments 12 A tightly clamped. [0046] By compressing the release button 32 as with one finger when gripping the rim, the ratchet teeth 36 , 38 are released as seen in FIG. 9 , allowing counter rotation to the release condition of FIG. 6 . [0047] FIGS. 11 and 12 show a second embodiment of a clamping device 10 A in which a pair of ovate smaller holes 28 A, 28 B are formed in web 24 of body 20 A and a pair of similarly shaped holes 30 A, 30 B in web 26 A of body 22 A, each hole in said 28 A, 28 B and 30 A, 30 B located diametrically opposite each other and offset from the common axis of relatively rotation of members 14 A, 16 A. Thus, a rope segment (not shown) can be inserted through each set of holes 28 A, 30 A, and 28 B, 30 B and simultaneously clamped when the members 14 A, 16 A are relatively rotated as seen in FIG. 5 , reducing the through opening size spaces through which the rope or line segments pass to clamp the same. This arrangement allows accommodation of a greater range of rope diameters. [0048] A diametrical reinforcing rib 58 is molded into the web 28 extending between the two holes 30 A, 30 B. [0049] The clamp device described is simple and rugged but highly reliable in operation, providing great convenience in securing or releasing lines on a boat, guy lines on a tent, tying down a load with a rope, etc.

A rope or line clamping device, including an assembly of two interfit tubular molded plastic members each having an internal web which are juxtaposed with each other and formed with elongated holes offset from the rotary axis of the members so that the holes progressively become more misaligned upon relative rotation of the members in a direction reducing the overlapping of the two holes. A ratchet mechanism holds the members in any relatively rotated position to hold rope or line segments inserted into the holes clamped together until the ratchet mechanism is selectively released allowing reverse relative rotation. In a second embodiment two sets of smaller holes are provided to separately clamp two rope or line segments.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoresistive strain sensing device in which diffused resistors are formed in a semiconductor single-crystal substrate. More particularly, it relates to a piezoresistive strain sensing device which is well suited to sensitively and precisely detect a stress field acting on an IC chip within a semiconductor package. 2. Description of the Prior Art Prior art devices wherein a mechanical stress resulting from the application of a strain, is converted into an electric signal by utilizing the piezoresistance effect of a semiconductor, include, for example, a semiconductor strain sensor as disclosed in the official gazette of Japanese Patent Application Laid-open No. 56-140229. In this device, a bridge circuit is formed by diffused resistors on a diaphragm of silicon, and a strain is measured by detecting the fractional change in resistivity based on the deformation of the diaphragm attendant upon a surface strain. Another prior art device has been attempted in which a diffused resistor is formed on a silicon substrate, and the substrate is buried in a resin which acts as sensing means, thereby to detect a two-dimensional stress field acting within a surface formed with the diffused resistor. In either case, however, only the detection on a specified stress component is achieved, and the use is limited. A three-dimensional stress field exists in a general structure, and mechanical strain-electricity transducers including the prior-art semiconductor strain sensors have had the problem that the three-dimensional stress field cannot be separately detected. SUMMARY OF THE INVENTION An object of the present invention is to provide a piezoresistive strain sensing device which sensitively and precisely detects a stress field acting in a semiconductor device. The semiconductor pressure conversion device according to the present invention is formed on a semiconductor single-crystal substrate and consists of a diffusion resistance gauge composed of a combination of p-type and n-type diffusion resistance layers, and of a temperature detecting unit composed of a combination of p-type and n-type diffusion layers. In general, the piezoresistance effect in a semiconductor such as silicon is expressed as: ##EQU1## using a resistivity ρ and a stress tensor X each of which is denoted by a tensor of the second order, and a tensor π of the fourth order. Since, in general, the tensor of the second order such as ρ or X is given by a six-component vector notation, the tensor π of the fourth order is expressed as a 6×6-element tensor. Here, π ik is called the "components of the piezoresistance tensor" and consists, in general, of 21 independent components. The number of the independent components decreases in a crystal of good symmetry, and it becomes 3 (π 11 , π 12 , π 44 ) in a crystal having the cubic symmetry such as silicon or germanium. Since (100) crystallographic plane substrates are generally used for manufacturing IC's, assume in this type of substrate a three-orthogonal x-y-z axis system in which the (100) crystallographic plane defines the x-y plane, and the [001] crystallographic axis and the x-axis are coincident with each other. Under this condition, the piezoresistive effects observed at diffusion resistors formed in parallel with the (100) crystallographic plane are expressed as follows: ##EQU2## where, δ ρij is a resistance value change rate calculated from a voltage measured in the j-direction when a current is applied in the i-direction of each diffusion resistor; σx, σy, σz are stress components along the three axis, respectively; τxy is a shearing stress component in the x-y plane; and π 11 , π 12 , and π 44 are proportional constants (piezoresistance coefficients). Accordingly, stress components which affect the fractional changes of resistivity of the diffused resistor of the (100) planes are four components (σ x , σ.sub.υ Ψσ z , σ xy ), and the resistivity changes which are independently detectible are of three components (δρ xx , δρ yy , δρ xy )001, so that the stress field acting in the crystal plane cannot be uniquely determined. Since, however, the piezoresistance coefficients (π 11 , π 12 , and π 44 ) differ depending upon the kinds of dopants used for diffused resistors, the resistivity changes can be independently detected in the respective diffused regions of the p-type diffused resistor and the n-type diffused resistor which are arranged in proximity to each other, the resistivity changes of a maximum of six components can be independently measured in both the regions. Accordingly, p-type and n-type diffused resistors are formed in the (100) plane of a semiconductor substrate whereby four resistor gauges capable of independent measurements can be provided, and the four stress components influential on the resistivity changes can be uniquely determined. FIG. 1 is a plan view of a first embodiment of a piezoresistive strain sensing device according to the present invention; FIG. 2 is a sectional view taken along line II--II' in FIG. 1; FIG. 3 is a plan view of a second embodiment of the piezoresistive strain sensing device of the present invention; FIG. 4 is a sectional view of a third embodiment of the piezoresistive strain sensing device of the present invention; FIG. 5 is a plan view of a fourth embodiment of the piezoresistive strain sensing device of the present invention; and FIG. 6 is a sectional view taken along line VI--VI' in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a piezoresistive strain sensing device according to the present invention will be described with reference to FIGS. 1 and 2. In this embodiment, a strain sensor is constructed by making a p-type diffused resistor 3 and an n-type diffused resistor 2 on an n-type silicon (100) substrate 1 by a use of the CMOS process. FIG. 1 shows a plan view, while FIG. 2 shows a sectional view taken along line II--II' in FIG. 1 and illustrates the formed states of the diffused resistors. The p-type diffused resistor 3 and the n-type diffused resistor 2, which are buried in a p-type diffused resistor layer 7, are respectively made in the shape of rectangles in proximity to each other, and electrode terminals 4 are provided on the four sides of each rectangle. The electrode terminals 4 are isolated by an SiO 2 film 5, and the whole surface is covered with a passivation film 6. Regarding the directions of the sides of the rectangles, the direction along the line II--II' is set to be the x-direction, and the direction orthogonal thereto in the same plane is set to be the y-direction. A method of measuring the changes of a resistivity in each diffused resistor will be described. Current is caused to flow across the two electrodes opposing in the x-direction, and the potential difference across both the electrodes is measured, whereby δρ xx in the equation (2) mentioned before is measured. A similar method is performed across the two electrodes opposing in the y-direction, whereby δρ yy in equation (2) is measured. In addition, current is caused to flow across the electrodes opposing in the x-direction, and the potential difference across the electrodes opposing in the y-direction is measured, whereby δρ xy in equation (2) is determined. Thus, the resistivity changes of the three independent components can be measured with the single diffused resistor. When δρ xy is measured with either of the p-type and n-type diffused resistors, and three of δρ nxx , δρ nyy , δρ pxx and δρ pyy are measured, four independent resistivity changes can be measured within the single crystal plane. According to the present embodiment, four independent resistivity changes can be measured within the (100) crystal plane of silicon, and this allows for the stresses σ x and σ y in the directions of two axes, a shear stress τ xy and a stress σ z perpendicular to the plane, which act on the crystal plane, to be uniquely determined. A second embodiment of the piezoresistive strain sensing device of the present invention will be described with reference to FIG. 3. This figure shows a plan view of a thin-film stress/strain sensor to which the present invention is applied. A single-crystal thin film of silicon having the (100) plane is formed on a film substrate (of, for example, PIQ) 8, and p-type diffused resistors 3 and n-type diffused resistors 2 are formed as shown in the figure. One end of each of these diffused resistors 2 and 3 are connected by a common pattern 12, and are held in communication with a common electrode terminal 13. The single-crystal thin film is produced by a thin-film manufacturing process such as vacuum evaporation, CVD (Chemical Vapored Deposition), sputtering evaporation or epitaxial growth. Here, when the p-type diffused resistors 3 are arranged along the conventional crystal axis <011> and the n-type diffused resistors 2 along <001>, the resistivity changes of the respective resistors are expressed as: ##EQU3## In equation (3), π ij denotes a piezoresistance coefficient in the case where the direction of the <001> crystal axis is brought into agreement with the directions of the three right-angled axes. Since the resistivity changes in the p-type diffused resistors 3 and the n-type diffused resistors 2 are independently measured, the four components of stresses (σ x , σ y , σ z , σ xy ) are uniquely determined. From this fact, it is apparent that the thin-film stress/strain sensor for semiconductors can be constructed. A third embodiment of the piezoresistive strain sensing device of the present invention will be described with reference to FIG. 4. This figure is a sectional view of a semiconductor pressure sensor. In the surface layer of an n-type silicon (100) single-crystal substrate 1 in the shape of a disc, a p-type diffused resistor 3 and an n-type diffused resistor 2 are formed to construct a gauge. The single-crystal substrate 1 is bonded to a glass substratum 10 by a low-melting glass 9. Further, an n + -type diffused resistor 11 is formed in a p-type diffused layer 7, to construct a p/n-junction, whereupon the temperature of the gauge is detected. Thus, a temperature compensation circuit is formed, and measurements in a wide temperature range become possible. Moreover, since the silicon substrate may be in the shape of a disc, a high degree of etching accuracy as in the case of making a diaphragm is dispensed with, so that enhanced production percentage is achieved. According to the embodiments thus far described, since four resistivity changes within the (100) crystal plane of a semiconductor can be measured, it is possible to realize a piezoresistive strain sensing device which can uniquely determine the four stress components acting on the (100) crystal plane; stress components in the directions of three right-angled axes, two of them being contained in the plane, and a shear stress acting within the plane. A fourth embodiment of the piezoresistive strain sensing device of the present invention will be described with reference to FIGS. 5 and 6. This embodiment is a stress sensor which is fabricated using an n-type silicon (111) single-crystal disc 21 as a substrate FIG. 5 is a plan view, while FIG. 6 is a schematic sectional view taken along line VI--VI' in FIG. 5. Six diffused resistors 22 and 23 formed on the substrate 21 consist of three p-type diffused layers 22 and three n-type diffused layers 23. One end of each of the respective layers 22 or 23 is connected by a single aluminum pattern 24 or 32. It is assumed that the individual diffused resistors 22 or 23 be formed at angular intervals of 45°. It is also assumed that the direction of the line VI--VI' agrees with the direction of the <112> crystal axis. One end of each of the three p-type diffused resistors 22 is connected to a common electrode terminal 29 through the single common A1 pattern 24, whereas the other ends thereof are connected to separate electrode terminals 31 through separate A1 patterns 30. Likewise, one end of each of the three n-type diffused resistors 23 is connected to a common electrode terminal 33 through the single common A1 pattern 32, whereas the other ends thereof are connected to separate electrode terminals 35 through separate A1 patterns 34. The n-type diffused resistors 23 are formed in a p-type diffused layer 25. In addition, the A1 patterns 24 etc. are isolated by an SiO 2 insulator film 26, and the whole surface is covered with a passivation film 27. The p-type diffused layer 25 is formed with an n-type diffused resistor 28, to simultaneously make a p/n-junction for temperature compensation. Now, the operation of this sensor will be described. The three right-angled axes are given with the x-direction being the direction of the line VI--VI', the y-direction being a direction orthogonal thereto within the plane and the z-direction being a direction perpendicular to the plane, and stresses in the axial directions and shear stresses within respective planes are respectively denoted by σ and τ. In FIG. 5, a resistivity on the line VI--VI' is denoted by ρ 2 , that on the left side thereof is denoted by ρ 1 , and that on the right side thereof is denoted by ρ 3 . Then, the corresponding resistivity changes are expressed as: ##EQU4## For diffused resistors of the p-type diffused layers 22 and those of the n-type diffused layers 23, the values of the piezoresistance coefficients π i (i=α, β, . . . ) are different, so that six sorts of independent resistivity changes can be measured. Since stress components contributing to the respective resistivity changes are of six sorts, the respective components of the stress tensor or the three-dimensional stress field are/is separately detected by solving the matrix of equation (1). The embodiment thus far described shows that a sensor for detecting a three-dimensional stress field can be realized, and that measurements at temperatures in a wide range are permitted by utilizing a p/n-junction for temperature compensation. In the foregoing embodiment, the individual diffused resistors 22 or 23 are formed at the angular intervals of 45°. This means that, on the (111) crystal plane, the lengthwise directions of the resistor layers are brought into agreement with the <112> crystal axis and the <110> crystal axis, while one resistor layer is arranged in the direction of 45° between them. In principle, however, the directions of the arrangement of the resistor layers may be as desired (except a case where two or more resistors become parallel among the same kind of diffused resistor layers). Although three diffused resistors of each type of conductivity are shown in FIG. 5, the number of resistors of each conductivity type may well be four or more. Since the number of stress components acting independently is six, the stress components are uniquely determined when there are at least three diffused resistors of each conductivity type, namely, at least six resistors in total. In the case of forming at least four diffused resistors of the same conductivity type, at least three of them may extend in crystal orientations differing from one another. In an actual measurement, changes in the resistivities of the diffused resistors are respectively detected. In each of the foregoing embodiments, the semiconductor single-crystal substrate may be replaced with a single-crystal thin film produced by a thin-film manufacturing process such as vacuum evaporation, CVD, sputtering or epitaxial growth. According to each embodiment described above, six sorts of independent resistivity changes caused by the piezoresistance effect can be detected on the same semiconductor single-crystal substrate and hence, a stress sensor for determining a three-dimensional stress field can be realized.

A piezoresistive strain sensing device is comprised of a semiconductor single-crystal substrate, having crystal indices in the (100) phase, and having p-type and n-type diffused resistors formed therein. A diffused resistance gauge is formed of the p-type and n-type resistors. Temperature compensation means are formed adjacent the resistance gauge in the substrate.

BACKGROUND OF THE INVENTION [0001] 1. Field of Invention [0002] The invention relates to human/computer interfaces on portable devices such as PDA's and other similar telecommunication systems, to provide portable software systems intended for rehabilitation by means of color therapy. [0003] 2. Prior Art [0004] Prior art is divided into three primary categories, diagnostic tools, rehabilitation treatment methods, and previously designed light therapy treatment methods. [0005] The first area of prior art is the manner of diagnostic tools used in the development of wave-front color therapy in conjunction with therapeutic prescriptions. To date, color therapy in conjunction with therapeutic prescription use has been a manual, often tedious process not capable of pinpointing the precise nanometer of a color's wavelength best suited for the patient's use. [0006] The second area of prior art is the manner of rehabilitation treatment methods for neurological impairments such as stroke, brain injury, CVA, and MS to name several, and learning disabilities such as Attention Deficit Disorder, and ADHD. [0007] There is a host of computer based, non-portable, dumb-terminal rehabilitation systems used within the structure of cognitive, vision and learning disability rehabilitations. They are geared at re-training the impaired or injured neurological processes. [0008] Unfortunately, there are two basic shortcomings to the conventional approach of neurological rehabilitations. These machines are only available to the rehabilitation facility due to cost and size and are therefore not available for private patient consumer use. This limits the amount of time a patient can spend using these rehabilitation tools due to a number of factors, as set forth below. [0009] First, a patient who is a candidate for neurological rehabilitation is often also attending physical and occupational therapies, recovering from surgeries or other treatments and procedures associated with their neurological assault. During the time crucial window of cognitive and visual rehabilitation, a patient's day is consumed with therapies and doctors visits, often leaving the time that can be spent on cognitive rehabilitation shortchanged or even completely neglected. [0010] Second, the neurologically impaired patient's rehabilitation is also subject to the schedules of their caretakers as they are often unable to transport themselves, inclement weather, flare-up of injuries, or office scheduling conflicts. [0011] Despite the enormous amount of time devoted to the rehabilitation process involving doctors and rehabilitation specialists, a patient spends a great deal of time waiting in medical waiting rooms, waiting for transportation between appointments, and at the end of the day, is often too exhausted to attend to cognitive rehabilitation and the associated exercises. This time can be recaptured with a portable rehabilitation device to make best use of spare time to become rehabilitation time. [0012] A patient who does not face the aforementioned problems can also use this device to maximize their rehabilitation, reducing rehabilitation expense while making best use of the window of maximum rehabilitative progress. [0013] Third, a fundamental problem in the conventional approach is that is does not fully take into account the need of the learning impaired student. [0014] A learning impaired student is paired with a learning specialist during school hours, which either robs time from their education or uses their break periods, leaving an already overworked student without a break during the day. The second approach is to team a student with a learning specialist after school, taking time away from homework and putting a student further behind in their work. [0015] Any adaptive technology devices that a mainstreamed student may be offered might not be available in all schools, and a student may often be embarrassed to use them in front of others students who may perceive a learning disability as a lack of intelligence on the part of the disabled student. Fear of such a perception may render a student reluctant or too embarrassed to use the adaptive tech tools designed to help them. [0016] Color Therapy has long been used medically. Color, or Light Therapy is used for a number of purposes, including, Seasonal Affected Disorder (SAD), dermatological purposes, cosmetic enhancement, as well as for Syntonic Optometry. The latter has been used for the past 70 years for treatment of several optometric disorders. Recently, it has been shown to be helpful in the diagnosis and treatment of brain injuries, Cerebro-vascular accidents (CVA), and other neurological disorders. [0017] There are, however, several failings of the treatments and therapies developed to date: 1) White light machines. Many light machines emit full spectrum white light, not specific and finite wavelengths. There are multiple benefits to being able to isolate a finite wavelength, as in the case of this claimed computer program: a. The white light machines available today, by their very nature, emit all wavelengths in the visible spectrum. For as therapeutic as certain wavelengths of color can be to a patient, another wavelength could be harmful or uncomfortable, and there is no way to omit the uncomfortable or harmful wavelengths from a white-light machine and only use the helpful ones for therapy. b. Many patients who suffer neurological problems suffer from photophobia, or sensitivity to light and glare. While some white light machines have a dimmer, this may not reduce brightness and glare enough for the patient and cause discomfort, and would not be therapeutic. c. Since all colors are emitted from a white light machine, it is impossible to determine what wavelengths could be most helpful to the patient. In contrast, this computer program can isolate the exact wavelength of color that is beneficial to the patient. d. White light machines often require extended periods of time per day to receive therapeutic benefit. By this program isolating to the most therapeutic range of wavelengths, the patient will receive the most precise diagnosis and the best therapy for their specific disorder in the shortest amount of time. This is essential as there is a limited window of time after neurological injury or onset of a neurological illness that a patient has to capture the majority of recovery they will make—thus, time is of the essence. 2) Methods of color therapy developed to date that isolate certain color spectrums are generally unable to provide the diagnostic benefits of the computer program claimed herein due to their inability to produce the scope of colors necessary. In addition, they also lack certain elements of the ideal color manipulation therapy. One such example is the use of lasers and radiation of certain colors on the eye, with the obvious side effects associated with lasers and radiation. Other methods of light therapy involve physically dangerous illumination apparatuses such as gas or flame, which are dangerous and prohibit unattended or at home use due to their very nature. None of these factors are an issue with the current claimed invention. SUMMARY OF THE INVENTION [0025] It is therefore an object of the current invention to use current and future computer and telecommunication handheld and mobile devices as a method of transportable rehabilitation, light therapy treatments, and a diagnostic device. The use of a handheld device is especially useful in this regard as these handheld devices have a life use beyond the rehabilitation of the patient, and are often distributed to those with neurological impairments by disability agencies making the procurement of such a device far more cost effective than any other rehabilitation device currently available. [0026] Software that is intended for rehabilitation can be adapted for handheld device use. Such software can be purchased or downloaded to the handheld device via the Internet or from the rehabilitation office. This allows the rehabilitation office to provide consistent rehabilitation when a patient is unable to attend. This would require a software suite available to the office, as well as a website for download of software to the handheld device. [0027] It is still a further object of the present invention that it provides a computer display for visually-impaired users that is convenient, lightweight, low-cost, minimally power hungry, and capable of portable operation without degraded performance. [0028] In addition to the objects above, and in all handheld or otherwise portable devices useful in the present invention, less portable means of display such as laptop computers, desktop computers, televisions, or any other telecommunication or display device are also useful in the present invention. [0029] A color light therapy computer method and apparatus has been produced with the capability to display a full range of wavelengths systematically delineated of the visual spectrum. Using said program claimed herein as a foundation application, with various modifications, the preciseness of the wave length production and display thereof allows for a diagnostic process and a host of rehabilitative and treatment applications to be produced from the same fundamental program. BRIEF DESCRIPTION OF THE DRAWINGS [0030] The above-mentioned features and objects of the present invention will become more apparent with reference to the following description taken in conjunction with the accompanying drawings wherein like reference numerals denote like elements and in which: [0031] FIG. 1 is a table illustrating the visible colors spectrum shifting combinations used in a computer program for a computer capable of at least 256,000,000 colors; [0032] FIG. 2 is a block diagram for an apparatus in accordance with the teachings of the present invention; [0033] FIG. 3 is a flow diagram illustrating the method of present invention; and [0034] FIG. 4 is a flow diagram illustrating the shifting of the combination of the visible color spectrum in a computer program of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0035] Although the visual system has been traditionally looked at as a sensory system to provide information about detail and spatial awareness, research has also documented that the eyes deliver important photopic information to brain centers which affect hormonal imbalance, diurnal cycle for sleep regulation, and metabolic function. John Ott has described in his research that various wavelengths in the photopic spectrum have significant affects on the growth of plants as well as human biological functions. [0036] The human eye responds to a visual spectrum between 400 nanometers and 700 nanometers. The change in wavelength is processed by the brain through the eyes and establishes the perception and interpretation of color. Shorter wavelength is perceived in the blue end of the spectrum while longer wavelength is perceived in the red end of the spectrum. It has also been documented that the retina of the eye is characteristically sensitive to long wavelengths in the central or macular region of the eye, while the peripheral part of the retina is more sensitive to short wavelengths or the blue spectrum. [0037] Two visual processing centers have been found in the brain. The occipital cortex is the primary area of the brain for establishing imagery and detail detection through central macular involvement. This portion of the visual system and brain relays information to higher cognitive and perceptual processes. This has been called the focal vision process. A second visual process relays approximately 20% of all of the sensory nerves from the eyes to a lower portion of the brain known as the midbrain or thalamus. It is here that the peripheral information received from the eyes is relayed and matched with balance and movement centers such as the kinesthetic, proprioceptive, and vestibular processes. This portion of the visual system has been called the ambient vision process. It organizes information related to spatial function for support of balance and anticipation of movement. This is the first part of the visual process that must respond to visual stimuli. Once information is matched between the ambient and sensory motor processes, it is feed-forwarded to the occipital cortex and 99% of the higher cerebral cortex. The purpose of which is to relay information particularly to the occipital cortex in order to pre-program it how to see the world spatially or more as a whole. It is responsible to establish relationships among the details as well as to spatially coordinate binocular integration cells to blend and merge the separate images of each eye into one. This process is called fusion. [0038] It is also determined that the focal and the ambient process not only respond to different wavelengths of the visual spectrum, but that they also organize a temporal component related to spatial function in two different manners. The focal process will tend to isolate and upon doing so, will attempt to slow time or temporal relationships. The ambient process conversely tends to speed up temporal relationships. A simple experiment will demonstrate this. If a drum with vertical stripes is rotated at a constant speed, one will perceive the speed of the stripes differently if they concentrate hard on each stripe and attempt to focalize the visual process compared to if they relax and attempt to stare through the drum not concentrating on each stripe. The focal process when engaged will cause the person to perceive that the rotating stripes will appear to slow down in temporal context whereas when staring through the drum and not concentrating on the stripes, the ambient visual process will tend to cause the subject to perceive that the stripes will speed up temporally. [0039] Understanding that the ambient and focal visual processes are critical for organization of space related to temporal function and that the organization of space and time must be established in order for higher cognitive perceptual processes to function properly, the function of the ambient and focal process in relationship to each other can alter function and performance of the individual and further, any interference neurologically with the relationship established between these two processes will interfere with aspects of spatial orientation, perceptual motor function, cognitive function, and higher perceptual interpretation. [0040] Following a neurological event such as a cerebrovascular accident (CVA), traumatic brain injury (TBI), multiple sclerosis (MS), cerebral palsy (CP), autism, etc., interference can alter the relationship between the ambient and focal process. This can cause a wide range of dysfunctions as well as symptoms. Characteristics of the dysfunction visually are that imbalances will occur in oculomotor function such as strabismus (ocular deviation) or variation in phoria (tendency for the eyes to deviate in alignment). Problems with convergence, accommodation, and sensory motor function for pursuit tracking and saccadic fixations are often evident. Also, following a neurological event that is related to higher brain dysfunction, a visual field loss will often occur affecting the common field projected by each eye such as with a homonymous hemianopsia. In this condition either the complete right or left visual field will be lost. The field loss, in turn, affects concepts of visual midline. When the visual midline shifts, individuals will then attempt to lean to one side and drift during ambulation. [0041] To perform the functions described above, an apparatus shown in block diagram in FIG. 2 is utilized. This apparatus utilizes a color display or array 2 which is fed with the display output of a central processing unit 4 . This central processing unit 4 may be any computer device such as a desktop computer, laptop, etc., which includes at least a microprocessor, random access memory, a keyboard, a semi-permanent storage system and a color display driver. As an input to the CPU 4 is clinician input 6 which may be the keyboard of the CPU 4 or some other device such as a touch screen, mouse, joy stick, etc. The CPU 4 is capable of providing data output directly to a portable device 8 such as a laptop computer, PDA, etc. Another data output of the CPU 4 goes to a conversion means 10 . The conversion means 10 may comprise a program within the CPU 4 for converting data stored in the CPU 4 into a format capable of being handled by other devices such as laptop computer, PDA's etc. belonging to or leased by the patient and then storing it on a floppy disk, CDROM, DVD, tape, etc. In addition, the conversion means 10 may also comprise a means for providing an interface between the CPU 4 and a local area network, intemet, phone line, etc. [0042] It should also be apparent to one of ordinary skill in the art that a new and “intelligent” devices with more computing capability are created such as intelligent VCR's, CDROM players and DVD players that the function of the device described above and the patients device could incorporate or in fact be such “intelligent” devices. [0043] Referring to FIGS. 1-4 , a mode of therapy for persons who have experienced a neurological event or a neurological dysfunction which interferes with the processing of ambient or focal image system, will be described in the numbered paragraphs 1-5 below. [0044] 1. The patient will be seated before a visual display 2 such as a television, CRT or LCD monitor, which will provide specific wavelengths that are perceived by the visual process as variation in color. The patient will be seated between 15-25 inches from the monitor. The display 2 will be adjusted using the clinician input 6 to provide initially a balance between the blue or short wavelength end of the visual spectrum and the red or long wavelength of the visual spectrum. For patients who have experienced a neurological event or cause that interferes with the ambient visual process, treatment will then be shifted to the blue end of the spectrum by the clinician. The patient will be given three five-minute therapy sessions exposed to short nanometer wavelengths of light. [0045] 2. The apparatus will then be adjusted through the clinician input 6 to the CPU 4 to shift from the blue end of the spectrum toward longer wavelengths. The design of the apparatus will enable the clinician to develop gradation shifting across the spectrum in a variety of ways as shown in FIG. 1 such that blue can be shifted in wavelength toward various spectrum portions such as green, yellow, or red in accordance with the flow diagram of FIG. 4 . This will enable the clinician to be very specific in delivering the direction of the therapy toward specific aspects of motor function, cognitive ftmction, or higher perceptual processes. For example, shifting from blue to red will be oriented to bring spatial relationships to development of figure/ground relationships and perceptual constancy. Shifting to the yellow end of the spectrum will have more specific function related to movement, object localization, and perceptual transformations. Shifting from blue toward the green end of the spectrum will be more related to affecting those patients who are experiencing a highly focalized nature to their vision such as in autism where the visual system will fragment the world into detail or parts. While FIG. 1 is described in terms of at least 256,000,000 possible colors, it should be apparent to one of ordinary skill in the art that the present invention would function with less color combinations. [0046] 3. A temporal component will be added to the color relationship by establishing a stroboscopic affect to the color presentation via clinician input 6 . For those patients who are highly focalized, blue light will begin in a very high stroboscopic affect since the ambient visual process has a higher critical fusion frequency that the focal process. The stroboscopic affect will be slowed as the wavelengths of light are shifted in the direction of the target and the spectrum from the short wavelengths. For those patients who are highly distractible, the temporal component will be started very slowly and increased toward the higher critical fusion frequency. This step could also include the use of multiple strobes or can be even be used without a strobe if either of these options is considered beneficial. [0047] 4. For those patients who are experiencing neurological dysfinction as related to attention deficit disorders, the color or wavelength variation will be shifted from red, yellow, or green toward the blue end of the spectrum in a similar manner described in method one (1). The temporal component will also be altered related to the critical fusion frequency of the focal or ambient process. [0048] 5. For those patients who have experienced a neurological event causing a visual field loss such as a homonymous hemianopsia, the clinician will adapt the display 2 so that half the portion of the screen will provide a color function while the other half of the screen will provide color and a stroboscopic affect. The stroboscopic affect will be delivered to the portion of the visual process that is in the homonymous hemianopic field. For patients with a field loss on the left side, a slow to rapid stroboscopic affect will be provided while fixation will be centered on a target in the middle of the screen. This is to establish half of the visual field in continuous wavefront modulation while the other half of the field related to the scotoma or field loss would be provided wavefront modulation in a stroboscopic affect. The stimulation in the stroboscopic affect as well as specific nanometers will be used therapeutically in an attempt to reestablish a temporal and spatial relationship of those cortical brain cells that no longer are matching information between focal and ambient processing. [0049] Frequently, patients who have suffered a CVA or TBI will have a homonymous hemianopsia. Stimulation of that field repeatedly will cause the cortical cells to reestablish the visual process in the affected field. The wavefront modulation system is designed as a therapeutic mechanism to treat these visual problems that up to this time no methodology or instrument invention has been found to improve function. [0050] Referring further to FIG. 3 , in operation the clinician will start the apparatus and provide initial operator input into the apparatus. Based on this initial input by the clinician, the color display 2 will be adjusted to provide the correct colors, shift and stroboscopic affect. After the patient has been exposed to the color display 2 for the required time, typically 5 minute sessions, the effect of the color therapy will be observed by the clinician who will determine whether or not the therapy is now at an optimum level. If no, there will be further adjustments made and if yes, the optimum color therapy program which has been developed during the session or sessions will be stored in the CPU 4 . So that the patient can utilize this optimum color therapy program developed during the session or sessions, the optimum color therapy program for this particular patient which is stored in the CPU 4 will be then either directly transferred to the portable device 8 of the patient or sent to the conversion means 10 for conversion either to a program in the format usable by the portable device of the patient or into a format which can be transferred over the internet, a local area network, telephone line, etc., to be accessed by a patient at a remote location. The control program for the operation shown in FIG. 3 can be easily created by one of ordinary skill in the art based upon the flow diagram of FIG. 3 . [0051] By providing the patient with the means for utilizing the optimum color therapy program developed specifically for the patient on a device in the possession of the patient and at a location and times of the patient's choice, many of the disadvantages of the prior art can be overcome. [0052] Still further, the apparatus and method of the present invention provides one or more of the following: [0053] 1) A method of diagnosis of optimal color wavelengths for devising an exact therapeutic prescription including nanometer specifications and hue-saturation to prescribe for individuals with a wide range of visual problems, including but not limited to learning disabilities and neurological problems. [0054] 2) A computer-implemented method for assisting a user in cognitive and vision rehabilitation, as well as the rehabilitation and assistance of learning disabilities via a handheld device to assist the visually impaired, learning impaired, as well as those in need of cognitive rehabilitation due to brain injury, stroke, CVA or other neurological injury or disease. [0055] 3) Adaptations of current rehabilitation software as outlined in other patents by the same inventors (Dara Medes, Heather Medes, William Padula) to be downloaded onto a handheld device. [0056] 4) A website to make said software suite available for download onto a handheld device. [0057] 5) A CD, DVD and any such other recordable medium devices to hold such software for distribution. [0058] 6) The software processes of converting rehabilitation software from dumb-terminal non-portable systems to software that is portable via any handheld or telecommunication device. [0059] 7) Neurological Treatment methods in or outside of traditional rehabilitation setting by using said software suite to do rehabilitation in a setting and schedule most convenient to the patient. [0060] 8) Treatments traditionally associated with light therapy including but not limited to vision therapy, sleep disturbance, headaches, asthma, depression, weight problems, adrenal and hormonal imbalances, dermatological enhancement, cosmetic enhancement, amongst others, can be available in a portable form not requiring constant office supervision. [0061] 9) Treatment services traditionally restricted to directly out of a doctor's office may now be monitored via wire or wireless telecommunication or processing devices, including any other form of transmission technology, or in a doctor's or therapist's office setting. This allows for treating the house bound or those geographically far away in or out of a traditional office treatment setting. [0062] The above description is for the purpose of teaching the person of ordinary skill how to practice the present invention, and it is not intended to detail all obvious modifications and variations of it, which will become apparent to the skilled worker upon reading the description. It is intended, however, that all such obvious modifications and variations be included within the scope of the present invention, which is defined by the following claims.

A method and apparatus of providing wave-front color therapy using a computer or portable handheld devices such as PDA's and other portable telecommunication devices to deliver a specific different nanometer wavelength of light to affect a wide variety of visual, binocular, function, perceptual, and cognitive-related vision imbalances that interfere with function and performance. The current proposed device would provide specific treatment for these difficulties by delivering different wavelengths of light through a computer monitor. The exact therapeutic prescription including nanometer specifications and hue-saturation will be prescribed for individuals with a wide range of visual problems caused by a traumatic brain injury, cerebrovascular accident, and Multiple Sclerosis, and the like, to name a few examples. This disclosure claims analog and digital relations of light as it relates to both the spatial and temporal relationship of light.

TECHNICAL FIELD The present invention relates to high-strength TRIP (transformation induced plasticity, strain-induced transformation)-aided steel sheets with excellent warm workability. Specifically, the present invention relates to high-strength steel sheets which are TRIP-aided steel sheets (TRIP-aided steel sheets) having significantly improved elongation as a result of warm working even having ultrahigh strengths on the order of 840 to 1380 MPa. BACKGROUND ART Steel sheets to be stamped (press-formed) and used typically in automobiles and industrial machines require both satisfactory strengths and excellent ductility. High-strength, high-ductility steel sheets have been developed so as to ensure collision safety and weight reduction of automobiles, while satisfying the aforementioned requirements. A TRIP-aided steel sheet is listed as one of them. The TRIP-aided steel sheet includes retained austenite (γR) formed in the structure and effectively utilizes such a property that the γR undergoes induced transformation (strain induced transformation: TRIP) during work deformation to help the steel sheet to have better ductility (see, for example, PTL 1). The TRIP-aided steel sheet is, however, disadvantageously inferior in workability [particularly in stretch flangeability (bore expandability)] so as to allow easy working into a complicated shape. The stretch flangeability is a property necessary for steel sheets for use typically as undercarriage parts of automobiles. Thus, a strong demand has been made to improve stretch flangeability in a TRIP-aided steel sheet also in order to promote the application of the TIP steel sheet typically to undercarriage parts where the weight reduction effect by the TRIP-aided steel sheet is most expected. Under these circumstances, the present applicants made various investigations so as to provide a steel sheet which maintains excellent strength-ductility balance by the action of γR and excels also in formability such as stretch flangeability. The investigations were made while focusing attention on effects of warm working to improve the stretch flangeability (see, for example, NPL 1 to 3). As a result, they found that a steel sheet, when being suitably controlled in average hardness of the matrix structure, carbon concentration in γR as a second phase, and volume fraction of γR and being subjected to warm working, can give a high-strength steel sheet having both better stretch flangeability and better elongation. An invention was made based on these findings (hereinafter referred to as “prior invention,” and a high-strength steel sheet according to the prior invention is referred to as a “steel sheet of the prior invention”), and a patent application was already filed on this invention (see PTL 2). The steel sheet of the prior invention is a high-strength steel sheet containing, on the percent by mass basis: carbon (C) in a content of from 0.05% to 0.6%, silicon (Si) and aluminum (Al) in a total content of from 0.5% to 3%, manganese (Mn) in a content of from 0.5% to 3%, phosphorus (P) in a content of 0.15% or less (excluding 0%), and sulfur (S) in a content of 0.02% or less (including 0%), in which the steel sheet has a matrix structure containing 70 percent by area or more of bainitic ferrite and/or granular bainitic ferrite relative to the total structure, the bainitic ferrite and/or granular bainitic ferrite having an average hardness in terms of Vickers hardness of 240 Hv or more, the steel sheet has a second phase structure containing 5 to 30 percent by area of retained austenite relative to the total structure, and the retained austenite has a carbon concentration (C γR ) of 1.0 percent by mass or more, and the steel sheet may further contain bainite and/or martensite. PTL 2 mentions that the steel sheet of the prior art has good properties probably because γR itself exhibits maximum plastic stability particularly in a temperature range of from 100° C. to 400° C. (preferably from 150° C. to 250° C.); and that this is achieved by controlling the structure as above and thereby suitably controlling the C γR (carbon concentration in γR) and the hardness of the matrix structure, where C γR significantly affects the TRIP effect due to strain induced transformation of γR, and the hardness of the matrix structure significantly affects the space constraint state of γR (see Paragraph [0023] in PTL 2). Particularly PTL 2 mentions that, from the viewpoint of exhibiting a TRIP (strain induced transformation working) effect, the steel sheet of the prior invention should essentially have a carbon concentration in γR (C γR ) of 1.0 percent by mass or more; and that the larger C γR is, the better (see Paragraph [0030] in PTL 2). However, after further investigations, the present inventors have found that the TRIP effect is maximally exhibited in warm working (100° C. to 250° C.) where the driving force of the stress-induced transformation upon deformation becomes small by controlling the C γR to a lower range of less than 1.0 percent by mass, which is lower than the specific range (1.0 percent by mass or more) in the prior invention; and that a steel sheet having further better ductility than that of the steel sheet of the prior invention, though slightly sacrificing stretch flangeability, can be obtained by further introducing a specific amount of polygonal ferrite. CITATION LIST Patent Literature PTL 1: Japanese Unexamined Patent Application Publication (JP-A) No. S60-43425 PTL 2: Japanese Patent (JP-B) No. 4068950 Non Patent Literature NPL 1: Akihiko NAGASAKA, Koh-ichi SUGIMOTO, and Mitsuyuki KOBAYASHI, “Improvement of Stretch-Flangeability by Transformation Induced Plasticity of Retained Austenite in High-strength Sheet Steels,” Materials and Processes (The Iron and Steel Institute of Japan, Collected Papers), CAMP-ISIJ “Discussion 35”, Vol. 8 (1995), pp. 556-559 NPL 2: Koh-ichi SUGIMOTO, Tsuyoshi KONDO, Mitsuyuki KOBAYASHI, and Shun-ichi HASHIMOTO, “Warm Stretch-Formability of TRIP-Aided Dual-Phase Steels (Effect of second-phase morphology-2),” Materials and Processes (The Iron and Steel Institute of Japan, Collected Papers), CAMP-ISIJ “Discussion 518,” Vol. 7 (1994), p. 754 NPL 3: Koh-ichi SUGIMOTO & Tetsuo TOYODA, “Formability of High-Strength TRIP-Aided Bainitic Cooled Sheet Steels,” Materials and Processes (The Iron and Steel Institute of Japan, Collected Papers), CAMP-ISIJ, Vol. 11 (1998), No. 4, pp. 400-403 SUMMARY OF INVENTION Technical Problem The present invention has been made as focusing attention on these circumstances, and an object thereof is to provide a high-strength steel sheet which exhibits TRIP effects maximally upon warm working and which may have even better ductility than that of the steel sheet of the prior invention. Solution to Problem An invention as claimed in claim 1 is a high-strength steel sheet with excellent warm workability. The steel sheet has a chemical composition, on the percent by mass basis (hereinafter the same is applied to contents in the chemical composition), including carbon (C) in a content of from 0.05% to 0.4%; silicon (Si) and aluminum (Al) [Si+Al] in a total content of from 0.5% to 3%; manganese (Mn) in a content of from 0.5% to 3%; phosphorus (P) in a content of 0.15% or less (excluding 0%); and sulfur (S) in a content of 0.02% or less (including 0%), with the remainder including iron and impurities, the steel sheet has a structure including: martensite and/or bainitic ferrite in a total amount of 45 to 80 percent by area relative to the total structure; polygonal ferrite in an amount of 5 to 40 percent by area relative to the total structure; and retained austenite in an amount of 5 to 20 percent by area relative to the total structure, in which the structure has a carbon concentration (C γR ) in the retained austenite of 0.6 percent by mass or more and less than 1.0 percent by mass, and the structure may further include bainite. An invention as claimed in claim 2 is the high-strength steel sheet with excellent warm workability according to claim 1 , in which the chemical composition further includes at least one element selected from the group consisting of: molybdenum (Mo) in a content of 1% or less (excluding 0%), nickel (Ni) in a content of 0.5% or less (excluding 0%), copper (Cu) in a content of 0.5% or less (excluding 0%), and chromium (Cr) in a content of 1% or less (excluding 0%). An invention as claimed in claim 3 is the high-strength steel sheet with excellent warm workability according to claim 1 or 2 , in which the chemical composition further includes at least one element selected from the group consisting of: titanium (Ti) in a content of 0.1% or less (excluding 0%), niobium (Nb) in a content of 0.1% or less (excluding 0%), vanadium (V) in a content of 0.1% or less (excluding 0%), and zirconium (Zr) in a content of 0.1% or less (excluding 0%). An invention as claimed in claim 4 is the high-strength steel sheet with excellent warm workability according to any one of claims 1 to 3 , in which the chemical composition further includes: calcium (Ca) in a content of 0.003% or less (excluding 0%) and/or a rare-earth element (REM) in a content of 0.003% or less (excluding 0%). Advantageous Effects of Invention The present invention can provide a high-strength steel sheet having further better ductility than that of the steel sheet of the prior invention. This is because the high-strength steel sheet of the present invention allows warm working to exhibit ductility improving effects maximally by containing martensite and/or bainitic ferrite in a total amount of 45 to 80 percent by area relative to the total structure, containing polygonal ferrite in an amount of 5 to 40 percent by area relative to the total structure, containing retained austenite in an amount of 5 to 20 percent by area relative to the total structure, and having a carbon concentration (C γR ) in the retained austenite of 0.6 percent by mass or more and less than 1.0 percent by mass. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a graphical representation illustrating how the working temperature, when varied, affects the tensile strength (TS), in which a steel sheet of the present invention is compared with a comparative steel sheet. FIG. 2 is a graphical representation illustrating how the working temperature, when varied, affects the elongation (EL), in which a steel sheet of the present invention is compared with a comparative steel sheet. DESCRIPTION OF EMBODIMENTS As has been described above, the present inventors have focused attention on TRIP-aided steel sheets which contain bainitic ferrite having a substructure with high dislocation density as in the steel sheet of the prior invention (however, bainitic ferrite and/or granular bainitic ferrite in PTL 2) and retained austenite (γR) and made further investigations to further improve ductility through warm working. As a result, the present inventors have found that the TRIP action can be maximally exhibited in warm working by allowing a steel sheet to have a lower carbon concentration in γR (C γR ) in the range of 0.6 percent by mass or more and less than 1.0 percent by mass, which is lower than the range specified in the prior invention (1.0 percent by mass or more) and by allowing the steel sheet to contain polygonal ferrite (hereinafter also simply referred to as “ferrite”) in a specific amount; and that the resulting steel sheet is a high-strength steel sheet having further better ductility, although slightly sacrificing the stretch flangeability (λ), as compared to the steel sheet of the prior invention. In this connection, the steel sheet of the present invention has a stretch flangeability (λ) of from about 10% to about 20%, which is slightly lower than that of the steel sheet of the prior invention (about 30%)). The present invention has been made based on these findings. Initially, the structure featuring the steel sheet of the present invention will be illustrated below. [Structure of Steel Sheet of the Present Invention] As has been described above, the steel sheet of the present invention is based on a structure of a TRIP-aided steel as with the steel sheet of the prior invention. However, the steel sheet of the present invention differs from the steel sheet of the prior invention in that the former contains polygonal ferrite in a specific amount and is controlled to have a carbon concentration in retained austenite (C γR ) of 0.6 percent by mass or more and less than 1.0 percent by mass; but the latter does not contain polygonal ferrite and is controlled to have a C γR of 1.0 percent by mass or more. <Containing Martensite and/or Bainitic Ferrite in a Total Amount of 45 to 80 Percent by Area Relative to the Total Structure> As used herein the “bainitic ferrite” corresponds to a bainite structure having, as a substructure, a lath-shaped structure with a high dislocation density, but, as containing no carbide therein, distinctly differs from the bainite structure; and also differs from polygonal ferrite structures having a substructure with no or very little dislocation density and also from quasi-polygonal ferrite structures having a substructure typically of fine sub-grains (see “Atlas for Bainitic Microstructures Vol. 1” issued by the Basic Research Group of the Iron and Steel Institute of Japan). This structure is observed as being acicular and is hardly distinguishable from bainite structures and polygonal ferrite structures in observation with an optical microscope or with a scanning electron microscope (SEM). Determination of distinct difference typically from the bainite structures and polygonal ferrite structures requires identification of substructures by observation with a transmission election microscope (TEM). Thus, the steel sheet of the present invention has a structure including martensite and/or bainitic ferrite as a principal structure, which martensite and/or bainitic ferrite bounds and constrains γR and thereby helps the ductility improving action to be exhibited effectively through the strain induced transformation effect of γR. The steel sheet of the present invention should contain the martensite and/or bainitic ferrite structure in a total amount of 45 to 80 percent by area (preferably 50 to 80 percent by area, and more preferably 53 to 60 percent by area) relative to the total structure. This allows the martensite and/or bainitic ferrite structure to exhibit the effects effectively. The amount of the martensite and/or bainitic ferrite structure may be decided based on the balance with γR, and it is recommended to control the amount appropriately so as to allow the steel sheet to exhibit desired properties. <Containing Polygonal Ferrite in an Amount of 5 to 40 Percent by Area Relative to the Total Structure> The presence of polygonal ferrite in a specific amount in the structure helps, combined with the TRIP action of γR as mentioned later, the steel sheet to have a further higher total elongation, though slightly sacrificing stretch flangeability. To exhibit the action effectively, polygonal ferrite should be present in an amount of 5 percent by area or more (preferably 10 percent by area or more, and more preferably 20 percent by area or more) relative to the total structure. In contrast, polygonal ferrite, if present in an excessively large amount, may significantly adversely affect the stretch flangeability, and, to avoid this, the upper limit is set to be 40 percent by area. <Containing Retained Austenite (γR) in an Amount of 5 to 20 Percent by Area Relative to the Total Structure> Retained austenite (γR) is useful for improvements in total elongation. To exhibit this action effectively, retained austenite should be present in an amount of 5 percent by area or more (preferably 10 percent by area or more, and more preferably 15 percent by area or more) relative to the total structure. In contrast, retained austenite, if present in an excessively large amount, may significantly adversely affect the stretch flangeability, and, to avoid this, the upper limit is set to be 20 percent by area. <Having Carbon Concentration (C γR ) in Retained Austenite (γR) of 0.6 Percent by Mass or More and Less than 1.0 Percent by Mass> In addition, the steel sheet has a carbon concentration in γR (C γR ) of 0.6 percent by mass or more and less than 1.0 percent by mass. As has been described above, the C γR significantly affects properties of TRIP (strain induced transformation working). According to customary techniques as in the steel sheet of the prior invention, C γR should essentially be 1.0 percent by mass or more, and it is believed that the more the C γR is, the better. The steel sheet of the present invention, however, has a C γR in the range of 0.6 percent by mass or more and less than 1.0 percent by mass, which range is lower than that in the steel sheet of the prior invention. This allows the steel sheet of the present invention to exhibit the TRIP effect and to have further better ductility in warm working (at temperatures from 100° C. to 250° C.) where the driving force of the stress-induced transformation upon deformation becomes small. The steel sheet of the present invention has a C γR of preferably 0.7 percent by mass or more and 0.9 percent by mass or less. <Others: Bainite (Including 0%)> The steel sheet of the present invention may include the aforementioned structure alone (mixed structure of martensite and/or bainitic ferrite, polygonal ferrite, and γR), but may further include bainite as another dissimilar structure within a range not adversely affecting the operation of the present invention. The bainite structure can inevitably remain during the manufacture process of the steel sheet of the present invention, but the less the bainite structure is, the better. It is therefore recommended to control bainite to be present in an amount of 5 percent by area or less, and more preferably 3 percent by area or less relative to the total structure. [Measurement Methods of Area Percentages of Respective Phases and Carbon Concentration in γR (C γR )] Measurement methods of area percentages of respective phases and carbon concentration in γR (C γR ) will be described below. The area percentages of respective structures in the steel sheet were measured by subjecting the steel sheet to LePera etching, identifying structures through observation with a transmission electron microscope (TEM; at a 1500-fold magnification), and measuring the area percentages of the structures through observation with an optical microscope (at a 1000-fold magnification). The area percentage of γR and the carbon concentration in γR (C γR ) were measured by grinding the steel sheet to a depth of one-fourth the thickness thereof, subjecting the ground steel sheet to chemical polishing, and measuring through X-ray diffractometry (ISIJ Int. Vol. 33 (1933), No. 7, p. 776). Next, the chemical composition (composition of components) constituting the steel sheet of the present invention will be described. Hereinafter all chemical compositions are indicated on the percent by mass basis. [Chemical Composition of Steel Sheet of Present Invention] Carbon (C) Content: 0.05% to 0.4% Carbon (C) element is essential for obtaining desired principal structures (martensite and/or bainitic ferrite, and γR). To exhibit the action effectively, carbon should be present in a content of 0.05% or more (preferably 0.10% or more, and more preferably 0.15% or more). However, a steel sheet having a carbon content of more than 0.4% may be unsuitable for welding. Total Content of Silicon (Si) and Aluminum (Al): 0.5% to 3% Silicon (Si) and aluminum (Al) elements effectively suppress the decompositions of γR into carbides. Among them, Si is also useful as a solid-solution strengthening element. To exhibit these actions effectively, Si and Al should be added in a total content of 0.5% or more. The total content is preferably 0.7% or more, and more preferably 1% or more. However, the elements, if added in a total content of more than 3%, may impede the formation of the martensite and/or bainitic ferrite structure; may often cause the weld bead to be brittle due to excessively high hot deformation resistance; and may adversely affect the surface quality of the steel sheet. To avoid these, the upper limit of the total content is set to be 3%. The total content is preferably 2.5% or less, and more preferably 2% or less. The Si content is desirably 2.0% or less, and the Al content is desirably 1.5% or less. The Si content and the Al content are each more than 0%. Manganese (Mn) Content: 0.5% to 3.0% Manganese (Mn) element effectively acts as a solid-solution strengthening element and also exhibits the action of promoting transformation to thereby accelerate the formation of the martensite and/or bainitic ferrite structure. In addition, this element is necessary for stabilizing austenite (γ) to thereby obtain desired γR. To exhibit these actions effectively, Mn should be added in a content of 0.5% or more. The Mn content is preferably 0.7% or more, and more preferably 1% or more. However, Mn, if added in a content of more than 3%, may cause adverse effects such as slab cracking. The Mn content is preferably 2.5% or less, and more preferably 2% or less. Phosphorus (P) Content: 0.15% or Less (Excluding 0%) Phosphorus (P) element is effective for ensuring desired γR. To exhibit the action effectively, phosphorus is recommended to be added in a content of 0.03% or more (more preferably 0.05% or more). However, phosphorus, if added in a content of more than 0.15%, may adversely affect secondary workability. The phosphorus content is more preferably 0.1% or less. Sulfur (S) Content: 0.02% or Less (Including 0%) Sulfur (S) element forms sulfide inclusions such as MnS, thereby causes cracking, and impairs workability. To avoid these, the sulfur content is set to be 0.02% or less and is preferably 0.015% or less. The steel for use in the present invention basically contains the chemical components with the remainder being substantially iron and inevitable impurities. The steel, however, may further contain the following permissible components, within ranges not adversely affecting the operation of the present invention. At least one element selected from the group consisting of: molybdenum (Mo) in a content of 1% or less (excluding 0%), nickel (Ni) in a content of 0.5% or less (excluding 0%), copper (Cu) in a content of 0.5% or less (excluding 0%), and chromium (Cr) in a content of 1% or less (excluding 0%) These elements are useful as strengthening elements for the steel and are effective for stabilizing γR and ensuring γR in a specific amount. To exhibit these actions effectively, it is recommended to add Mo in a content of 0.05% or more (more preferably 0.1% or more), Ni in a content of 0.05% or more (more preferably 0.1% or more), Cu in a content of 0.05% or more (more preferably 0.1% or more), and Cr in a content of 0.05% or more (more preferably 0.1% or more), respectively. However, if the Mo and Cr contents each exceed 1%, or if the Ni and Cu contents each exceed 0.5%, the effects are saturated, thus being economically ineffective. More preferably, the Mo content is 0.8% or less, the Ni content is 0.4% or less, the Cu content is 0.4% or less, and the Cr content is 0.8% or less. At least one element selected from the group consisting of: titanium (Ti) in a content of 0.1% or less (excluding 0%), niobium (Nb) in a content of 0.1% or less (excluding 0%), vanadium (V) in a content of 0.1% or less (excluding 0%), and zirconium (Zr) in a content of 0.1% or less (excluding 0%) These elements have effects of precipitation strengthening and of forming a finer structure and are useful to help the steel sheet to have a higher strength. To exhibit these actions effectively, it is recommended to add Ti in a content of 0.01% or more (more preferably 0.02% or more), Nb in a content of 0.01% or more (more preferably 0.02% or more), V in a content of 0.01% or more (more preferably 0.02% or more), and Zr in a content of 0.01% or more (more preferably 0.02% or more), respectively. However, the effects may be saturated if the elements are added each in a content of more than 0.1%, thus being economically inefficient. More preferably, the Ti content is 0.08% or less, the Nb content is 0.08% or less, the V content is 0.08% or less, and the Zr content is 0.08% or less. Calcium (Ca) in a Content of 0.003% or Less (Excluding 0%) and/or Rare-Earth Element (REM) in a Content of 0.003% or Less (Excluding 0%) Calcium (Ca) element and REMs (rare-earth elements) control the form of sulfides in the steel and are thereby effective for improving workability. Exemplary rare-earth elements for use in the present invention include Sc, Y, and lanthanoid elements. To exhibit these actions effectively, it is recommended to add Ca and the REM each in a content of 0.0003% or more (more preferably 0.0005% or more). However, the effects may be saturated if these elements are added each in a content of more than 0.003%, thus being economically inefficient. The contents are each more preferably 0.0025% or less. Next, a preferred method for manufacturing the steel sheet of the present invention will be illustrated below. [Preferred Method for Manufacturing Steel Sheet of the Present Invention] Initially, a steel having a chemical composition within the above-specified range is heated to a temperature in the austenite and ferrite (γ+α) dual-phase region and soaked. Specifically, the soaking is performed by heating at a temperature of 750° C. or higher (preferably 780° C. or higher) and lower than 850° C. (preferably 840° C. or lower) for 100 to 1000 seconds (preferably 300 to 600 seconds). After soaking, the steel is cooled (supercooled) at an average cooling rate of 30° C./s or more (preferably 40° C./s or more, more preferably 50° C./s or more, and particularly preferably 70° C./s or more) to a temperature in the range of 150° C. or higher (preferably 200° C. or higher) and 350° C. or lower (preferably 300° C. or lower); held at the supercooling temperature for 60 seconds or shorter (preferably 5 to 50 seconds); reheated at an average heating rate of 2° C./s or more (preferably 10° C./s or more) to a temperature in the range of higher than the supercooling temperature, and 300° C. or higher (preferably 350° C. or higher, and more preferably 400° C. or higher) and 480° C. or lower (preferably 450° C. or lower); held in this temperature range for 60 seconds or longer (preferably 300 seconds or longer) and 1000 seconds or shorter (preferably 600 seconds or shorter) (austempering). The steel sheet of the prior invention is manufactured through the steps of soaking at a temperature in the austenite-single region, quenching, and austempering performed in this order. Thus, heating is performed at a temperature in the austenite single-phase region, and this impedes the formation of polygonal ferrite. In addition, the austempering is performed immediately after quenching, and thereby the strength increases with a lowering austempering temperature, but C γR also increases. This is because as follows. Initially, with a lowering austempering temperature, the formed bainitic ferrite has a higher hardness and thereby has a higher strength. Independently, the carbon concentration C γR is determined by how much degree carbon is enriched in the austenite side with the formation of bainitic ferrite which contains substantially no carbon as a solid solution. The carbon concentration C γR increases with a lowering austempering temperature, because austenite having a higher carbon concentration becomes stable with a lowering temperature. Accordingly, the steel sheet of the prior invention should be subjected to austempering at a low temperature of 450° C. or lower so as to have a high tensile strength of 840 MPa or more, and thereby necessarily has a C γR of 1 percent by mass or more. In contrast, the steel sheet of the present invention is manufactured by the sequential steps of soaking at a temperature in the (γ+α) dual-phase region, supercooling, reheating, and austempering performed in this order. The heating in the (γ+α) dual-phase region as above helps the formation of polygonal ferrite in a desired amount. In addition, the steel is once supercooled to a predetermined temperature range prior to the austempering, and then reheated to an austempering temperature and held at that temperature to perform austempering. Thus, the steel can have a high tensile strength of 840 MPa or more, can include polygonal ferrite having satisfactory ductility, and can have a low C γR of less than 1.0 percent by mass simultaneously. While detailed mechanisms still remain unknown, reasons of this are probably as follows. Specifically, during the cooling process down to a supercooling state and during the reheating process, a structure is initially partially formed, which structure has a dislocation density and hardness higher than those of bainitic ferrite and contains carbon as a supersaturated solid solution, where the bainitic ferrite will be formed upon austempering. The remainder remains as austenite and as polygonal ferrite formed upon heating in the dual-phase region. The partial structure with a high dislocation density is tempered while discharging carbon to the austenite side during austempering, thereby has a decreased dislocation density and becomes a structure similar to that of bainitic ferrite. However, this structure originally had a high dislocation density and, even after the process, maintains a dislocation density higher than that of bainitic ferrite which is formed during austempering. Specifically, the steel surely has a sufficient strength even when austempered at a temperature higher than the temperature in the case where soaking and subsequent austempering are performed without supercooling. The treatments through these steps allow the steel to have both a high strength and a low carbon concentration C γR , because C γR decreases with an elevating austempering temperature. Upon austempering, the partial structure with a high dislocation density formed during supercooling changes into a structure similar to bainitic ferrite, i.e., a structure having a lath-shaped substructure and including no carbide therein and is not distinguishable from bainitic ferrite by observation with regular microscopes (optical microscope, SEM, and TEM). For this reason, the both structures are collectively referred to as “bainitic ferrite.” The supercooling, if performed at an excessively low temperature, may allow martensite transformation to proceed, and this may impede discharge of carbon into the austenite during austempering after reheating, and the resulting steel may not contain retained austenite in a necessary amount. In contrast, the supercooling, if performed at an excessively high temperature, may fail to lower the C γR , because the difference between the supercooling temperature and the austempering temperature is small. The supercooling, if performed at the supercooling temperature for an excessively long holding time, may fail to give retained austenite in a necessary amount as above, due to proceeding of martensite transformation. The holding time may be short, but is preferably certain duration (5 seconds or longer) from the viewpoint of reproducibility of temperature control in a real operation. The cooling steps of soaking in the (γ+α) dual-phase region and subsequent supercooling are important particularly for obtaining the desired principal structure, unlike the steel sheet of the prior invention. By soaking in the (α+γ) dual-phase region and subsequently quenching in the above manner, the desired martensite and/or bainitic ferrite (principal structure) can be formed while allowing polygonal ferrite to be formed in a predetermined amount. Among conditions, the average cooling rate significantly affects the form of γR, is thereby extremely important, and should be controlled within the above-specified range so as to allow γR in a predetermined form to be formed between laths of the martensite and/or bainitic ferrite structure. The average cooling rate is not critical in its upper limit, and the higher is, the better. However, the average cooling rate is desirably controlled suitably in consideration of the real operation level. As is described above, the austempering after supercooling and subsequent reheating is very important for the tempering of the structure which is formed during supercooling and has a high dislocation density, for the formation of bainitic ferrite, for carbon enrichment (concentration) into the austenite phase, and for the suppression of decomposition of retained austenite into carbides, which retained austenite is formed with these. Limitation in holding time in austempering within the range effectively suppresses the decomposition of regained austenite into carbides. Austempering, if performed at an excessively high temperature, may cause retained austenite to be readily decomposed into carbides to thereby fail to remain as retained austenite in a predetermined amount. In contrast, austempering, if performed at an excessively low temperature or if performed for an excessively short holding time, may fail to allow carbon to be concentrated in retained austenite. A portion with a low C γR gives martensite in the cooling process after austempering, but the formation of such martensite is acceptable within a range not adversely affecting the operation of the present invention The bainite structure may further be formed in the step, within a range not adversely affecting the operation of the present invention. Plating (and, if desired, a subsequent alloying treatment) may be performed within a range not adversely affecting the operation of the present invention and not significantly decomposing the desired structure. The steel sheet of the present invention manufactured by the method, when subjected to warm working, can give a high-strength steel sheet which has further better ductility than that of the steel sheet of the prior invention, although slightly sacrificing the stretch flangeability. As used herein the term “warm working” refers to warm forming at a temperature of from 100° C. to 250° C. (preferably from 120° C. to 200° C., and most preferably around about 150° C.). The steel sheet may be soaked so that the entire steel sheet is in the temperature range. As is demonstrated by the after-mentioned experimental examples, the steel sheet of the present invention, when subjected to warm working, gives a steel sheet which has, as compared to a steel sheet obtained from the steel sheet of the prior invention through warm working, an equivalent tensile strength (TS) at room temperature, an elongation under warm conditions (warm EL) higher by about 40%, and a higher product of the tensile strength (TS) at room temperature and warm elongation (EL under warm conditions) by as much as about 30% to about 40%, thus exhibiting significant improving effects. The product is an index of balance between the tensile strength (TS) at room temperature and the warm elongation (EL) (compare Steel No. 1 with Steel No. 13 or Steel No. 15 in Table 5 below). The steel sheet of the present invention has high forming limit upon warm working and is thereby advantageously usable even for working into parts having complicated shapes, such as parts constituting center pillars and parts constituting front pillars. The resulting warm-formed parts obtained through warm working of the steel sheet of the present invention have a high yield stress and a large maximum load upon deformation due to bainitic ferrite contained in a large amount as its structure, and they are expected to exhibit high load bearing properties. They are therefore advantageously usable typically as parts constituting side sills, parts constituting roof rails, and other parts. The warm-formed parts may probably be resistant to scale generation and have relatively good paint application properties, because the warm working is performed at a temperature not so high as in hot working. They are therefore advantageously usable typically as parts constituting floor cross members, parts constituting roof panels, and other parts. In addition, the warm-formed parts obtained through warm working of the steel sheet of the present invention, when being allowed to contain retained austenite remained in a suitable amount, can have good elongation properties and a high work hardening factor even after working and are expected to exhibit such properties that they are resistant to rupture even when used as parts and absorb energy in a large quantity. For these reasons, the warm-formed parts may probably be advantageously used even as, for example, parts constituting front side members and parts constituting rear side members. EXAMPLES Experimental Example 1 Analysis on Chemical Composition How the chemical composition, when varied, affects mechanical properties was investigated in this experimental example. Specifically, slab specimens were prepared by vacuum ingot making of steels having the chemical compositions given in Table 1 (resulting hot-roiled sheets had a gage of 2.0 mm), and the slabs were subjected to heat treatments under the manufacture conditions given in Table 2. The resulting steel sheets were examined by measuring the area percentages of respective phases and the carbon concentration in γR (C γR ) according to the measurement methods described in [Description of Embodiments] above. In addition, to determine how the working temperature affects the mechanical properties, the tensile strength (TS), YS [lower yield point (yield stress)], and elongation [i.e., total elongation (EL)] were measured at working temperatures (tensile temperature) varying from 20° C. to 350° C. according to the following procedure. In a tensile test, TS, YS, and EL were measured using a Japanese Industrial Standards (JIS) No. 5 specimen. The tensile test was performed at a strain rate of 1 mm/s. The results are indicated in Table 3. TABLE 1 (in percent by mass) Material Steel No. C Si Al Si + Al Mn P S Others 1 0.07 1.50 0.36 1.86 2.36 0.007 0.0010 Mo: 0.92 2 0.19 1.56 0.34 1.90 2.75 0.009 0.0009 — 3 0.19 0.48 0.11 0.59 2.49 0.010 0.0013 — 4 0.24 1.58 0.38 1.96 0.69 0.009 0.0012 Mo: 0.55, Ti: 0.04 5 0.18 0.75 1.12 1.87 2.37 0.007 0.0010 Mo: 0.32 6 0.19 1.98 0.47 1.96 2.46 0.009 0.0012 Ni: 0.12 7 0.18 1.25 0.64 1.89 2.39 0.008 0.0011 Cu: 0.43 8 0.19 1.11 0.88 1.99 2.49 0.010 0.0013 Cr: 0.57 9 0.18 0.89 1.09 1.98 2.74 0.011 0.0010 Ti: 0.06 10  0.19 1.82 0.13 1.95 2.45 0.009 0.0012 Nb: 0.04 11  0.21 1.75 0.23 1.98 2.48 0.010 0.0013 V: 0.07 12  0.18 1.55 0.33 1.88 2.38 0.008 0.0011 Ca: 0.002 13  0.19 1.11 0.85 1.96 2.46 0.009 0.0012 REM: 0.002 14a 0.01a 1.56 0.30 1.86 2.36 0.007 0.0010 — 15a 0.18 0.23 0.13 0.36a 2.38 0.008 0.0011 — 16a 0.18 1.75 0.13 1.88 0.34a 0.008 0.0011 — 17  0.18 1.49 0.38 1.87 2.52 0.009 0.0008 Zr: 0.05 (a: out of the range specified in the present invention) TABLE 2 Soaking Supercooling Supercooling Austempering Austempering Manufacture temperature Soaking time Cooling rate temperature holding time Reheating rate temperature time No. (° C.) (s) (° C.) (° C.) (s) (° C./s) (° C.) (s) 1 850 150 50 350 5 20 400 500 2 780 300 50 350 5 20 400 500 3 760 600 50 350 5 20 400 500 4 750 500 50 350 5 20 400 500 5 780 500 50 350 5 20 400 500 6 780 500 50 350 5 20 400 500 7 780 400 50 350 5 20 400 500 8 780 500 50 350 5 20 400 500 9 780 500 50 350 5 20 400 500 10  780 500 50 350 5 20 400 500 11  780 500 50 350 5 20 400 500 12  780 500 50 350 5 20 400 500 13  780 500 50 350 5 20 400 500 14b  900b 500 50 350 5 20 400 500 15  820 500 50 350 5 20 400 500 16  760 500 50 350 5 20 400 500 17  780 500 30 350 5 20 400 500 (b: out of recommended range) TABLE 3 Mechanical properties at a temperature Mechanical (150° C.-300° C.) Product of properties at where EL room- Material Structure room temperature attains maximum temperature TS Steel Steel Manufacture M + BF PF γ R Cγ R YS TS EL YS TS EL and warm EL No. No. No. (%) (%) (%) (mass %) (MPa) (MPa) (%) (MPa) (MPa) (%) (MPa. %) Judgment 1 1 1 52.9 38.2 8.9 0.88 458 995 14.3 471 846 27.3 27164 ◯ 2 2 2 54.4 33.6 12.0 0.89 527 1198 11.2 539 958 23.5 28153 ◯ 3 3 3 51.9 35.2 12.9 0.84 458 975 15.2 501 887 25.5 24863 ◯ 4 4 4 67.6 15.7 16.7 0.92 694 1389 9.6 731 1306 21.5 29864 ◯ 5 5 5 55.0 30.7 14.3 0.85 506 1234 10.2 599 1086 24.8 30603 ◯ 6 6 6 55.8 28.9 15.3 0.89 538 1251 11.1 576 1063 25.2 31525 ◯ 7 7 7 55.6 31.2 13.2 0.82 591 1232 12.1 601 1010 25.6 31539 ◯ 8 8 8 56.1 32.2 11.7 0.79 605 1210 12.8 604 1029 24.5 29645 ◯ 9 9 9 56.0 32.5 11.5 0.91 577 1247 10.6 605 1094 24.5 30552 ◯ 10 10  10  53.5 33.8 12.7 0.80 522 1214 11.8 588 1068 23.6 28650 ◯ 11 11  11  54.2 34.6 11.2 0.77 510 1237 10.7 612 1101 21.2 26224 ◯ 12 12  12  49.2 37.6 13.2 0.82 468 1201 12.4 543 1021 24.5 29425 ◯ 13 13  13  53.5 33.9 12.6 0.81 516 1199 13.6 546 1007 25.6 30694 ◯ 14 14a 14b 40.5a 56.3a 3.2a 0.90 345 879 17.8 332 642 23.4  20569a X 15 15a 15  64.1 35.7 0.2a 1.18a 501 1043 9.2 512 845 15.5  16167a X 16 16a 16  67.2 30.5 2.3a 0.99 428 995 10.2 439 856 14.3  14229a X 17 17  17  54.1 34.5 11.4 0.82 531 1221 11.7 592 1071 23.5 28694 ◯ (a: out of the range specified in the present invention, b: out of recommended range, BF: bainitic ferrite, PF: polygonal ferrite, γ R : retained austenite ◯: room-temperature TS ≧ 840 MPa; and product of the room-temperature TS and the warm EL ≧ 24000 MPa. %, X: room-temperature TS < 840 MPa; or product of the room-temperature TS and the warm EL < 24000 MPa. %) These results indicate as follows. Initially, Steels Nos. 1 to 13 and 17 are all inventive steels which are obtained by warm working of steel sheets manufactured under recommended manufacture conditions using material steels having chemical compositions within ranges specified in the present invention and are high-strength steel sheets having good balance between the tensile strength at mom temperature and the elongation under warm conditions (product of room-temperature TS by warm EL). In contrast, following comparative steels having chemical compositions not satisfying any of conditions specified in the present invention have following problems, respectively. Steel No. 14 is a sample having a small carbon content, suffers from an excessively large amount of polygonal ferrite and an insufficient amount of γR, and thereby has a product of the room-temperature TS and the warm ET, not satisfying the acceptance criterion. Steel No. 15 is a sample having a small total amount of Si and Al (Si+Al), suffers from, even though having a low strength, a low EL under warm conditions because of containing substantially no desired γR, and thereby has a product of the mom-temperature TS and the warm EL not satisfying the acceptance criterion. No. 16 is a sample having a small Mn content, suffers from insufficient formation of γR, has an inferior elongation under warm conditions, and thereby has a product of the room-temperature TS and the warm EL not satisfying the acceptance criterion Experimental Example 2 Analysis of Manufacture Conditions In this experimental example, steel sheets were manufactured (hot-rolled steel sheets had a gage of 2.0 mm) under conditions given in Table 4 using the slab specimen of Material Steel No. 9, and how the working temperature affects the mechanical properties was examined by the procedure of Experimental Example 1, while varying the working temperature (tensile temperature) from 20° C. to 350° C. The material steel used herein is a steel having the chemical composition satisfying the conditions specified in the present invention. The results are indicated in Table 5, and how TS and EL, respectively, vary depending on the working temperature is illustrated as graphs in FIGS. 1 and 2 . TABLE 4 Soaking Supercooling Supercooling Austempering Austempering Manufacture temperature Soaking time Cooling rate temperature holding time Reheating rate temperature time No. (° C.) (s) (° C.) (° C.) (s) (° C./s) (° C.) (s) 1 780 500 50 350 5 20 400 500 2 840 200 50 350 5 20 400 500 3 780 500 30 350 5 20 400 500 4 780 500 50 160 5 20 400 500 5 780 500 50 350 60  20 400 500 6 780 500 50 350 5 10 400 500 7 780 300 50 350 5  5 400 500 8 780 500 50 350 5 20 300 500 9 780 500 50 350 5 20 480 500 10  780 500 50 350 5 20 400  60 11  780 500 50 350 5 20 400 750 12  780 500 50 350 5 20 400 1000  13b 780 500 50 — b — b — b 400 500 14b  740b 500 50 350 5 20 400 500 15b  880b 500 50 350 5 20 400 500 16b 780 800 50  130b 5 20 400 500 17b 780 800 50 350 90b 20 400 500 18b 780 500 50 350 5  1b 400 500 19b 780 500 50 350 5 20  275b 500 20b 780 500 50 350 5 20  500b 500 21b 780 500 50 350 5 20 400  30b 22b 780 500 50 350 5 20 400 1500b (b: out of recommended range) TABLE 5 Mechanical properties at a temperature Mechanical (150° C.-300° C.) Product of properties at where EL room- Material Structure room temperature attains maximum temperature TS Steel Steel Manufacture M + BF PF γ R Cγ R YS TS EL YS TS EL and warm EL No. No. No. (%) (%) (%) (mass %) (MPa) (MPa) (%) (MPa) (MPa) (%) (MPa. %) Judgment 1 9 1 56.0 32.5 11.5 0.91 577 1247 10.6 605 1094 24.5 30552 ◯ 2 9 2 79.3 7.0 13.7 0.90 723 1357 9.9 756 1190 22.2 30125 ◯ 3 9 3 49.8 38.1 12.1 0.89 666 1098 12.2 701 965 25.4 27889 ◯ 4 9 4 60.1 33.4 6.5 0.82 602 1295 11.5 629 1140 21.6 27972 ◯ 5 9 5 62.6 31.5 5.9 0.99 589 1274 12.5 621 1120 20.9 26627 ◯ 6 9 6 55.1 32.5 12.4 0.93 621 1260 13.1 665 1110 23.2 29232 ◯ 7 9 7 52.7 33.1 14.2 0.91 578 1241 13.6 603 1098 24.3 30156 ◯ 8 9 8 62.6 31.5 5.9 0.96 603 1301 8.9 542 1152 20.9 27191 ◯ 9 9 9 51.0 32.2 16.8 0.75 466 1011 15.8 499 880 26.2 26488 ◯ 10 9 10  57.3 31.9 10.8 0.69 697 1322 10.9 743 1174 19.3 25515 ◯ 11 9 11  49.0 33.0 18.0 0.95 675 1298 12.4 721 1150 22.5 29205 ◯ 12 9 12  52.8 32.5 14.7 0.98 674 1225 13.1 710 1091 22.9 28053 ◯ 13 9 13b 59.2 30.3 10.5 1.21a 591 1234 13.5 593 1084 16.8  20731a X 14 9 14b 47.7 45.6a 6.7 0.93 401 878 17.3 432 760 26.5  23267a X 15 9 15b 85.5 3.9a 10.6 0.89 641 1377 8.7 682 1210 16.7  22996a X 16 9 16b 69.4 30.3 0.3a 0.67 610 1254 11.5 641 1105 12.7  15926a X 17 9 17b 63.6 32.5 3.9a 0.93 632 1283 12.1 675 1134 15.1  19373a X 18 9 18b 66.1 29.5 4.4a 0.88 641 1298 12.5 678 1141 18.2  23624a X 19 9 19b 63.2 31.1 5.7 1.22a 651 1403 7.6 692 1254 10.9  15293a X 20 9 20b 58.0 32.2 9.8 0.51a 415 889 16.9 540 789 18.7  16624a X 21 9 21b 65.6 30.2 4.2a 0.89 587 1284 7.9 614 1131 12.2  15665a X 22 9 22b 64.3 31.8 3.9a 0.88 554 1179 11.8 591 1041 14.5  17096a X (a: out of the range specified in the present invention, b: out of recommended range, BF: bainitic ferrite, PF: polygonal ferrite, γ R : retained austenite ◯: room-temperature TS ≧ 840 MPa; and product of the room-temperature TS and the warm EL ≧ 24000 MPa. %, X: room-temperature TS < 840 MPa; or product of the room-temperature TS and the warm EL < 24000 MPa. %) These results indicate as follows. Steels Nos. 1 to 12 are all inventive steels which are obtained by warm working of steel sheets manufactured under recommended manufacture conditions using material steels having chemical compositions within ranges specified in the present invention and are high-strength steel sheets having good balance between the tensile strength at room temperature and the elongation under warm conditions (product of the room-temperature TS and the warm EL). In contrast, the following comparative steels having structures not satisfying any of the conditions specified in the present invention have the following problems, respectively. Steel No. 13 is prepared by performing austempering immediately after soaking without supercooling and subsequent reheating, is a sample corresponding substantially to the steel of the prior art, except for undergoing soaking in a different temperature range, has a C γR of 1 percent by mass or more, and thereby has a product of the mom-temperature TS and the warm EL not satisfying the acceptance criterion. Steel No. 14 is a sample undergone soaking at a temperature lower than the (γ+α) dual-phase region, includes polygonal ferrite in an excessively large area percentage, and thereby has a mom-temperature TS and a product of the mom-temperature TS and the warm EL neither satisfying the acceptance criteria. Steel No. 15 is a sample undergone soaking at a temperature in the austenite single-phase region higher than the (γ+α) dual-phase region and is a sample corresponding substantially to the steel of the prior invention, except for undergoing, after soaking, supercooling and subsequent reheating. This steel includes bainitic ferrite in an insufficient area percentage and thereby has a room-temperature TS and a product of the mom-temperature TS and the warm EL neither satisfying the acceptance criteria. Steel No. 16 is a sample undergone supercooling at an excessively low temperature and includes γR in an insufficient area percentage. This sample thereby has a low elongation under warm conditions and has a product of the room-temperature TS and the warm EL not satisfying the acceptance criterion. Steel No. 17 is a sample undergone supercooling performed for an excessively long holding time and includes γR in an insufficient area percentage due to decomposition of γR into carbides. This sample thereby has a low elongation under warm conditions and has a product of the room-temperature TS and the warm EL not satisfying the acceptance criterion. Steel No. 18 is a sample undergone reheating performed at an excessively low reheating rate and includes γR in an insufficient area percentage due to decomposition of γR into carbides. This sample thereby has a low elongation under warm conditions and has a product of the mom-temperature TS and the warm EL not satisfying the acceptance criterion. Steel No. 19 is a sample undergone austempering performed at an excessively low temperature, thereby has an excessively high C γR , and has a product of the mom-temperature TS and the warm EL not satisfying the acceptance criterion Steel No. 20 is a sample undergone austempering performed at an excessively high temperature, thereby has an insufficient C γR , and has a product of the room-temperature TS and the warm EL not satisfying the acceptance criterion Steels Nos. 21 and 22 are samples undergone austempering for a time out of the recommended range, include γR in an insufficient area percentage, and thereby have a product of the mom-temperature TS and the warm EL not satisfying the acceptance criterion. As is illustrated in FIG. 1 and FIG. 2 , a comparison between Steel No. 1 in Table 5 as a steel sheet of the present invention and Steel No. 13 in Table 5 as a comparative steel sheet demonstrates that the steel sheet of the present invention has an FT, distinctly significantly higher than that of the comparative steel sheet, even though the both steel sheets have increasing effects on FT, in the warm working temperature range but have slightly lowered TS. Specifically, the results demonstrate that the present invention may provide, through warm working, high-strength steel sheets which extremely excel in elongation properties although slightly sacrificing the strength. While the present invention has been described in detail with reference to the specific embodiments thereof, it is obvious to those skilled in the art that various changes and modifications can be made in the invention without departing from the spirit and scope of the invention. The present application is based on Japanese Patent Application No. 2010-068477 filed on Mar. 24, 2010 and Japanese Patent Application No. 2011-021596 filed on Feb. 3, 2011, the entire contents of which are incorporated herein by reference. INDUSTRIAL APPLICABILITY High-strength steel sheets according to the present invention are useful as steel sheets to be stamped and to be used typically in automobiles and industrial machines.

Disclosed is a high-strength steel plate with excellent warm workability that has a component composition comprising, in mass %, 0.05 to 0.4% C, 0.5 to 3% Si+Al, 0.5 to 3% Mn, no more than 0.15% P (not including 0%), and no more than 0.02% S (including 0%), with the remainder comprising iron and impurities, and a composition that includes a total of 45 to 80% martensite and/or bainitic ferrite in terms of the area ratio relative to the entire composition, 5 to 40% polygonal ferrite in terms of the area ratio relative to the entire composition, and 5 to 20% retained austenite in terms of the area ratio relative to the entire composition, wherein the C concentration (C γR ) within said residual austenite is in the range of 0.6 mass % to less than 1.0 mass %, and that furthermore may include bainite. In the high-strength steel plate, TRIP effects are achieved to the fullest extent in warm working, and increased ductility over prior steel plates is reliably achieved.

BACKGROUND OF THE INVENTION The present invention relates to a DNA containing a cDNA sequence coding for a human luteinizing hormone-human chorionic gonadotropin receptor protein (human LH/hCG receptor protein), the human LH/hCG receptor protein, and a method for preparing the protein. The human luteinizing hormone-human chorionic gonadotropin receptor proteins (human LH/hCG receptor proteins) exist in the Leydig cells in the testis, the theca cells in the ovary, the granulosa cells, the corpus luteum cells and the interstitial cells, and play a central role in reproductive physiology. In the male and the female who is not pregnant, the LH/hCG receptor proteins are acted on only by luteinizing hormone (LH) produced in the anterior lobe of the pituitary and secreted therefrom. In the pregnant female, however, the LH/hCG receptor proteins in the ovary are acted on also by human chorionic gonadotropin (hCG) produced by the placenta. LH and hCG are members of a family of glycoprotein hormones also including thyroid-stimulating hormone (TSH) and follicle-stimulating hormone (FSH). Each of these four hormones has a molecular weight of 28 to 38 kD, and is a heterodimer glycoprotein in which a specific β subunit relating to receptor binding specificity is bound to an α subunit common to these hormones. The glycosyl moiety of these hormones seem to play an important role in signal introduction. The β subunits of both LH and hCG are closely related to each other in their structure. These two hormones bind to the same receptor and induce the same biological reaction. The similarity between these glycoprotein hormones and the action by these hormones on the receptors to enhance the activity of adenylate cyclase mediated by G-proteins reveal that these receptors have a common mechanism of hormone-induced activation. The increases of adenosine 3′,5′-monophosphate (cyclic AMP) necessarily lead to the synthesis and secretion of steroids. A family of G protein-coupled receptors are identified whose members are characterized by the common structural feature of having seven transmembrane domains which are known to relate to the signal introduction and binding to small ligands. On the other hand, TSH and FSH receptors have been compared with the LH/hCG receptors. As a result, of the G protein-coupled receptors, these receptors of the pituitary glycoprotein hormones are characterized by the presence of a large glycosylated domain which is grafted onto a structure containing seven transmembrane segments and putatively considered to be positioned on the outside of cells. The structure of the LH/hCG receptors have not been elucidated so well yet, because the receptors are present in very low amounts and sensitive to proteolysis. For rat and porcine LH/hCG receptors, however, complementary DNAs (cDNAs) of these receptors are isolated and the amino acid sequences thereof are also deduced from these DNAs [ Science 245, 494 (1989) for rats and Science 245, 525 (1989) for pigs]. For the rat and porcine LH/hCG receptors, the structure thereof has been thus elucidated. For the human LH/hCG receptors, however, the structure thereof is not revealed. Considering to use the human LH/hCG receptors as therapeutic drugs and analytical reagents for humans, it is necessary to make clear the structure and properties thereof. SUMMARY OF THE INVENTION The present inventors have recognized that important contributions will be made to future studies and medical treatments, if an human LH/hCG receptor can be collected from humans and further prepared by recombinant technology. As a result, the present inventors have first succeeded in cloning cDNA coding for a human LH/hCG receptor from a cDNA library of the human ovary by using the complementary DNA of a rat LH/hCG receptor as a probe, and in elucidating a complete nucleotide sequence thereof. Further, the present inventors have also succeeded in elucidating an amino acid sequence of the human LH/hCG receptor from this cDNA and in pioneering the mass production of this receptor by recombinant technology. This receptor is very similar to the rat and porcine receptors. However, the differences are such that each receptor can be recognized to be a different one. In accordance with the present invention, there are provided (1) a human luteinizing hormone-human chorionic gonadotropin receptor protein, (2) a DNA comprising a cDNA sequence coding for a human luteinizing hormone-human chorionic gonadotropin receptor protein, (3) a transformant carrying a DNA comprising a cDNA segment coding for a human luteinizing hormone-human chorionic gonadotropin receptor protein, and (4) a method for preparing a human luteinizing hormone-human chorionic gonadotropin receptor protein which comprises culturing the transformant described in (3), accumulating a protein in a culture broth, and collecting the same. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a nucleotide sequence (SEQ ID NO:1) of a human LH/hCG receptor protein DNA segment, as well as an amino acid sequence (SEQ ID NO:2) deduced therefrom; and FIG. 2 shows the amino acid sequence of the human LH/hCG receptor protein and amino acid sequences (SEQ ID NO:2) of other known LH/hCG receptor proteins and proteins having similar action, comparing them to one another. FIGS. 3 and 4 are SDS-PAGE diagrams which show expression of HLHR protein in Example 2. FIG. 5 is a graph which shows that the protein obtained according to the present invention has response ability to hCG. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present inventors cloned two kinds of cDNAs of the human luteinizing hormone-human chorionic gonadotropin receptor protein to deduce a primary structure of the complete protein (FIG. 1 ). The first methionine in this sequence is considered to be an initiator codon. This is followed by an amino acid sequence having the characteristics of a signal peptide with a cleavage site present. A possible model for construction of the protein was suggested by hydropathy analysis and comparison with the rat and porcine LH/hCG receptors SEQ ID NO:3 and 4 respectively (FIG. 2 ). A putative extracellular domain of 335 amino acids precedes a region of 267 amino acids that displays seven possible transmembrane segments (regions surrounded by rectangles in FIG. 2 and labeled I to II). There is a 72 amino acid COOH-terminal intracellular domain. The mature protein may consist of 674 amino acids (75632 daltons). In addition to this protein, 25 signal peptides (the 1st to 25th amino acids in FIGS. 1 and 2) exist. However, these peptides are cut off during synthesis of the receptor, and therefore the mature protein of the receptor is considered to consist of 674 amino acids (the 26th to 699th amino acids, SEQ ID NO:10 is the amino acid sequence of SEQ ID NO:9). At the primary structure level, this extracellular domain has about 85% homology with the rat and porcine LH/hCG receptors and 45% homology with TSH and FSH receptors (in FIG. 2, hLH/hCGR indicates the human LH/hCG receptor; rLH/hCGR indicates the rat LH/hCG receptor; pLH/hCGR indicates the porcine LH/hCG receptor; hTSHR indicates the human TSH receptor [ Biochem. Biophys. Res. Comm . 166, 394 (1990)]; and rFSHR indicates the rat FSH receptor [ Mol. Endo . 4, 525 (1990)]). Six potential glycosylation sites are found in the putative extracellular domain (underlined portions in FIG. 1 ). Clusters of cysteine residues are present in the NH 2 -terminal portion and between the putative extracellular and transmembrane domains of the above protein. Since these cysteine residues are conserved in the LH, FSH and TSH receptors, while not wishing to be bound by theory, it may be said that the formation of disulfide bonds is crucial for the conformational integrity of the large extracellular domains of glycoprotein hormone receptors. The domain considered to contain the transmembrane domains has about 90% homology with the rat and porcine LH/hCG receptors, and 70% homology with the TSH and FSH receptors. Serine and threonine residues are found with high frequency in a putative intercellular domain having three sites which is possibly phosphorylated by protein kinase C (FIG. 1 ). Since the phosphorylation by protein kinase specific to the receptors play a role in agonist specific decoupling of adrenergic receptors from the G proteins, it is important to know whether the phosphorylation in at least one of these sites causes any functional changes of the LH/hCG receptors. In the present invention, in addition to a clone having a large open reading frame, a clone coding for a shorter protein was obtained. The large clone is the 1st to 699th amino acid residues (SEQ ID NO:2) in FIG. 1 (SEQ ID NO:1), and the truncated type is one from which a region of the 227th to 289th amino acid residues surrounded by a rectangle (SEQ ID NO:7) is lacking. This pattern suggests that the cleavage mechanism necessary to complete mRNA has selectivity. These results are very similar to the data of the porcine LH/hCG receptor. The role of this truncated type receptor is not understood well, and it is not known either whether this LH/hCG receptor is physiologically active as a monomer or an oligomer. In humans, this TSH receptor can be a target of autoimmune reaction which leads to hyper- or hypo-stimulation of the thyroid gland by autoantibodies in Grave's disease and idiopathic myxedema. Thus, not only for contributions to diagnosis and management of ovarian diseases, but also for better understanding of ovarian physiology, it is necessary to isolate the human LH/hCG receptor and to know its characteristics. FIG. 2 shows the amino acid sequence of the novel human luteinizing hormone-human chorionic gonadotropin receptor protein (SEQ ID NO:2) obtained in the present invention, and compares this amino acid sequence with the amino acid sequences of the rat and porcine luteinizing hormone-human chorionic gonadotropin receptor proteins (SEQ ID NO:3 and 4 respectively) and the FSH and TSH receptors (SEQ ID NO:6 and 5 respectively) having similar action. The same amino acid residue as appears in the human luteinizing hormone-human chorionic gonadotropin receptor protein of the present invention, is represented by “.”, and an amino acid residue different from that of the human LH/hCG receptor is represented by the appropriate symbol as defined herein. CONSENSUS shown in FIG. 2 indicates amino acid residues common to all the glycoproteins shown in FIG. 2 . The illustration of CONSENSUS results in introduction of lacking portions “-” into the formulae in FIG. 2 . Accordingly, the number representing the amino acids is counted excluding these lacking portions. For a DNA sequence, the DNA coding for the human LH/hCG receptor of the present invention contains the nucleotide sequence (SEQ ID NO:1) shown in FIG. 1 or a portion thereof. As the cDNA coding for the human LH/hCG receptor of the present invention, any cDNA may be used as long as it contains a nucleotide sequence coding for an amino acid sequence of the human LH/hCG receptor. For example, DNA containing the nucleotide sequence (SEQ ID NO:1) shown in FIG. 1 or a portion thereof is preferably used. The nucleotide sequence (SEQ ID NO:1) shown in FIG. 1 is an example of cDNA sequences coding for the human LH/hCG receptor obtained in the present invention. In the present invention, for example, an expression vector having the cDNA containing the nucleotide sequence coding for the human LH/hCG receptor can be prepared by the following process: (a) Messenger RNA (mRNA) is isolated from human LH/hCG receptor-producing cells. (b) Single stranded complementary DNA (cDNA) is synthesized from the mRNA, followed by synthesis of double stranded DNA. (c) The complementary DNA is introduced into a phage or a plasmid. (d) Host cells are transformed with the recombinant phage or plasmid thus obtained. (e) After cultivation of the transformants thus obtained, plasmids or phages containing the desired DNA are isolated from the transformants by an appropriate method such as hybridization with a DNA probe coding for a portion of the rat LH/hCG receptor or immunoassay using an anti-LH/hCG receptor antibody. (f) The desired cloned DNA is cut out from the recombinant DNA. (g) The cloned DNA or a portion thereof is ligated downstream from a promoter in the expression vector. The mRNA coding for the human LH/hCG receptor can be obtained from various human LH/hCG receptor-producing cells, for example, germ cells such as the Leydig cells in the testis, the capsular cells in the ovary, the granulosa cells, the corpus luteum cells and the interstitial cells. Methods for preparing the MRNA from the human LH/hCG receptor-producing cells include the guanidine thiocyanate method [J. M. Chirgwin et al., Biochemistry 18, 5294 (1979)] and the like. Using the mRNA thus obtained as a template, cDNA is synthesized by use of reverse transcriptase, for example, in accordance with the method of H. Okayama et al. [ Molecular and Cellular Biology 2, 161 (1979); and ibid . 3, 280 (1983)]. The cDNA thus obtained is introduced into the plasmid. The plasmids into which the cDNA may be introduced include, for example, pBR322 [Gene 2, 95 (1977)], pBR325 [Gene 4, 121 (1978)], pUC12 [Gene 19, 259 (1982)] and pUC13 [Gene 19, 259, each derived from Escherichia coli , and pUB110 derived from Bacillus subtilis [Biochemical and Biophysical Research Communication 112, 678 (1983)]. However, any other plasmid can be used as long as it is replicable and viable in the host cell. Examples of the phage vectors into which the cDNA may be introduced include λgt11 [R. Young and R. Davis, Proc. Natl. Acad. Sci. U.S.A . 80, 1194 (1983)]. However, any other phage vector can be used as long as it is viable in the host cell. Methods for introducing the cDNA into the plasmid include, for example, the method described in T. Maniatis et al., Molecular Cloning , Cold Spring Harbor Laboratory, p.239 (1982). Methods for introducing the cDNA into the phage vector include, for example, the method of T. V. Hyunh et al. [ DNA Cloning, A Practical Approach 1, 49 (1985)]. The plasmid thus obtained is introduced into an appropriate host cell such as Escherichia and Bacillus. Examples of Escherichia described above include E. coli K12DH1 [Proc. Natl. Acad. Sci. U.S.A . 60, 160 (1968)], M103 [Nucleic Acids Research 9, 309 (1981)], JA221 [Journal of Molecular Biology 120, 517 (1978)], HB101 [Journal of Molecular Biology 41, 459 (1969)] and C600 [Genetics 39, 440 (1954)]. Examples of Bacillus described above include Bacillus subtilis MI114 [Gene 24, 255 (1983)] and 207-21 [Journal of Biochemistry 95, 87 (1984)]. Methods for transforming the host cell with the plasmid include, for example, the calcium chloride method or the calcium chloride/rubidium chloride method described in T. Maniatis et al., Molecular Cloning , Cold Spring harbor Laboratory, p.249 (1982). When the phage vector is used, for example, it can be transduced into proliferated E. coli , using the in vitro packaging method. Human LH/hCG receptor-cDNA libraries containing human LH/hCG receptor cDNA can be purchased from the market, though obtainable by the methods described above. For example, a cDNA library of the LH/CG receptor is available from Clontech Laboratories, Inc., U.S.A. Methods for cloning human LH/hCG receptor cDNA from the human DNA library include, for example, the plaque hybridization method using phage vector λcharon 28A and rat LH/hCG receptor cDNA as a probe [T. Maniatis et al., Molecular Cloning , Cold Spring Harbor Laboratory, (1982)]. The human LH/hCG receptor cDNA thus cloned may be subcloned, for example, in pBR322, pUC12, pUC13, pUC18, pUC19, pUC118 and pUC119 to obtain the human LH/hCG receptor cDNA, if necessary. The nucleotide sequence of the cDNA thus obtained is determined, for example, by the Maxam-Gilbert method [A. M. Maxam and W. Gilbert, Proc. Natl. Acad. Sci. U.S.A . 74, 560 (1977)] or the dideoxy method [J. Messing et al., Nucleic Acids Research 9, 309 (1981)], and the existence of the human LH/hCG receptor cDNA is confirmed in comparison with the known amino acid sequence. As described above, the cDNA coding for the human LH/hCG receptor protein is obtained. FIG. 1 shows the nucleotide sequence of the cDNA (SEQ ID NO:1) determined by the dideoxy method for the cDNA coding for the human LH/hCG receptor protein obtained in Example 1 described below, and the amino acid sequence proved from that nucleotide sequence. The cDNA coding for the human LH/hCG.receptor protein (SEQ ID NO:2) cloned as described above can be used as is, or after digestion with a restriction enzyme if desired, depending on the intended use. A region intended to be expressed is cut out from the cloned cDNA and ligated downstream from a promoter in a vehicle (vector) suitable for expression, whereby the expression vector can be obtained. The cDNA has ATG as a translation initiating codon at the 5′-terminus thereof and may have TAA, TGA or TAG as a translation terminating codon at the 3′-terminus. The translation initiating codon and translation terminating codon may be added by use of an appropriate synthetic cDNA adaptor. A promoter is further ligated upstream therefrom for the purpose of expressing the cDNA. Examples of the vectors include the above plasmids derived from E. coli such as pBR322, pBR325, pUC12 and pUC13, the plasmids derived from Bacillus subtilis such as pUB110, pTP5 and pC194, plasmids derived from yeast such as pSH19 and pSH15, bacteriophages such as λ phage, and animal viruses such as retroviruses and vaccinia viruses. As the promoter used in the present invention, any promoter is available as long as it is suitable for expression in the host cell selected for the gene expression. When the host cell used for transformation is Escherichia, it is preferable that a trp promoter, a lac promoter, a recA promoter, a λP L promoter, a lpp promoter, etc. are used. When the host cell is Bacillus, it is preferable that a SPO1 promoter, a SPO2 promoter, a penp promoter, etc. are used. When the host cell is yeast, it is preferable that a PHO5 promoter, a PGK promoter, a GAP promoter, an ADH promoter, etc. are used. In particular, it is preferable that the host cell is Escherichia and the promoter is the trp promoter or the λP L promoter. When the host cell is an animal cell, a SV-40 derived promoter, a retrovirus promoter, a metallothionein promoter, a heat shock promoter, etc. are each usable. An enhancer is also effectively used for expression. Using a vector containing the cDNA coding for the mature peptide of the human LH/hCG receptor protein thus constructed, transformants are prepared. The host cells include, for example, Escherichia, Bacillus, yeast and animal cells. Specific examples of the above Escherichia and Bacillus include strains similar to those described above. Examples of the above yeast include Saccharomyces cerevisiae AH22, AH22R − , NA87-11A and DKD-5D. Examples of the animal cells include monkey cell COS-7, Vero, Chinese hamster cell (CHO), mouse L cell and human FL cell. The transformation of the above Escherichia is carried out, for example, according to the method described in Proc. Natl. Acad. Sci. U.S.A . 69, 2110 (1972) or Gene 17, 107 (1982). The transformation of the above Bacillus is conducted, for example, according to the method described in Molecular & General Genetics 168, 111 (1979). The transformation of the yeast is carried out, for example, according to the method described in Proc. Natl. Acad. Sci. U.S.A . 75, 1929 (1978). The transformation of the animal cells is carried out, for example, according to the method described in Virology 52, 456 (1973). Thus, transformants are obtained which have been transformed with the expression vector containing the cDNA coding for the human LH/hCG receptor. When bacterial transformants are cultured, a liquid medium is particularly suitable as a medium used for culture. Carbon sources, nitrogen sources, inorganic compounds and others necessary for growth of the transformants are contained therein. Examples of the carbon sources include glucose, dextrin, soluble starch and sucrose. Examples of the nitrogen sources include inorganic or organic materials such as ammonium salts, nitrates, corn steep liquor, peptone, casein, meat extracts, soybean meal and potato extract solution. The inorganic compounds include, for example, calcium chloride, sodium dihydrogenphosphate and magnesium chloride. Yeast, vitamins, growth promoting factors and so on may be further added thereto. The pH of the medium is preferably about 5 to 8. As the medium used for cultivation of Escherichia, for example, M9 medium containing glucose and Casamino Acids (Miller, Journal of Experiments in Molecular Genetics 431-433, Cold Spring Harbor Laboratory, New York, 1972) is preferably used. In order to make the promoter act efficiently, a drug such as 3-β-indolylacrylic acid may be added thereto if necessary. When the host cell is Escherichia, the cultivation is usually carried out at about 15 to 43° C. for about 3 to 24 hours, with aeration or agitation if necessary. When the host cell is Bacillus, the cultivation is usually carried out at about 30 to 40° C. for about 6 to 24 hours, with aeration or agitation if necessary. When yeast transformants are cultured, for example, Burkholder minimum medium [K. L. Bostian et al., Proc. Natl. Acad. Sci. U.S.A . 77, 4505 (1980)] is used as the medium. The pH of the medium is preferably adjusted to about 5 to 8. The cultivation is usually carried out at about 20 to 35° C. for about 24 to 72 hours, with aeration or agitation if necessary. When animal cell transformants are cultured, examples of the mediums include MEM medium containing about 5 to 20% fetal calf serum [ Science 122, 501 (1952)], DMEM medium [ Virology 8, 396 (1959)], RPMI1640 medium ( The Journal of the American Medical Association 199, 519 (1967)] and 199 medium [ Proceeding of the Society for the Biological Medicine 73, 1 (1950). The pH is preferably about 6 to 8. The cultivation is usually carried out at about 30 to 40° C. for about 15 to 60 hours, with aeration or agitation if necessary. The human LH/hCG receptor protein can be isolated and purified from the culture described above, for example, by the following method. When the human LH/hCG receptor protein is extracted from the cultured cells, the cells are collected by methods known in the art after cultivation. Then, the collected cells are suspended in an appropriate buffer solution and disrupted by ultrasonic treatment, lysozyme and/or freeze-thawing. Thereafter, a crude extracted solution of the human LH/hCG receptor mature peptide is obtained by centrifugation or filtration. The buffer solution may contain a protein denaturant such as urea or guanidine hydrochloride, or a surface-active agent such as Triton X-100. When the human LH/hCG receptor protein is secreted in the culture solution, a supernatant is separated from the cells by methods known in the art after the conclusion of cultivation, and then collected. The separation and purification of the human LH/hCG receptor contained in the culture supernatant or the extracted solution thus obtained can be performed by an appropriate combination of known separating and purifying methods. The known separating and purifying methods include methods utilizing solubility such as salt precipitation and solvent precipitation, methods mainly utilizing a difference in molecular weight such as dialysis, ultrafiltration, gel filtration and SDS-polyacrylamide gel electrophoresis, methods utilizing a difference in electric charge such as ion-exchange column chromatography, methods utilizing specific affinity such as affinity chromatography, methods utilizing a difference in hydrophobicity such as reverse phase high performance liquid chromatography and methods utilizing a difference in isoelectric point such as isoelectro-focussing electrophoresis. A method may also be used in which an antibody to a fused protein expressed by fusing the human LH/hCG receptor complimentary DNA together with E. coli -derived DNA lacZ is used as an immunoaffinity column. The activity of the human LH/hCG receptor protein thus formed can be measured by an enzyme immunoassay using a specific antibody. The cells transfected or transformed with the cDNA of the present invention can allow the human LH/hCG receptor protein to be produced in large amounts. The human LH/hCG receptor protein produced here is channeled into the study of ovarian physiology, the supply of antibodies to the receptor, the diagnosis and management of ovarian or testicular diseases such as ovulation aberration or oligospermia, and the development of contraceptives. In humans, this TSH receptor can be a target of autoimmune reaction which leads to hyper- or hypo-stimulation of the thyroid gland by autoantibodies in Grave's disease and idiopathic myxedema. The LH/hCG receptor might therefore suppress the LH action in vivo or can conduct hyperstimulation in stead of LH to cause morbidity in the human genital system. The anti-receptor antibody can be detected by producing the receptor by any of the above-described methods, labeling it and examining whether one binding to it (antibody) is present in vivo or not. In addition, it is considered that inhibition of the LH action by an antibody obtained by expressing a portion or all of the receptor cDNA, namely the application of the antibody as a contraceptive, is possible. There have been described above in detail the cloning of the cDNA coding for the human LH/hCG receptor protein, the preparation of the expression vectors for the human LH/hCG receptor protein, the production of the transformants thereby, the production of the human LH/hCG receptor protein by using the transformants and utility thereof. When nucleotides, amino acids and so on are indicated by abbreviations in this specification and drawings, the abbreviations adopted by the IUPAC-IUB Commission on Biochemical Nomenclature or commonly used in the art are employed. For example, the following abbreviations are used. When the amino acids are capable of existing as optical isomers, it is understood that the L-forms are represented unless otherwise specified. DNA: Deoxyribonucleic acid cDNA: Complementary deoxyribonucleic acid A: Adenine T: Thymine G: Guanine C: Cytosine RNA: Ribonucleic acid mRNA: Messenger ribonucleic acid dATP: Deoxyadenosine triphosphate dTTP: Deoxythymidine triphosphate dGTP: Deoxyguanosine triphosphate dCTP: Deoxycytidine triphosphate ATP: Adenosine triphosphate EDTA: Ethylenediaminetetraacetic acid SDS: Sodium dodecyl sulfate Gly or G: Glycine Ala or A: Alanine Val or V: Valine Leu or L: Leucine Ile or I: Isoleucine Ser or S: Serine Thr or T: Threonine Cys or C: Cysteine Met or M: Methionine Glu or E: Glutamic acid Asp or D: Aspartic acid Lys or K: Lysine Arg or R: Arginine His or H: Histidine Phe or F: Phenylalanine Tyr or Y: Tyrosine Trp or W: Tryptophan Pro or P: Proline Asn or N: Asparagine Gln or Q: Glutamine The precise chemical structure of the human luteinizing hormone-human chorionic gonadotropin receptor proteins of the present invention will depend on a number of factors. Because ionizable amino and carboxyl groups are present in these proteins, a particular protein may be obtained as an acidic or basic salt, or in neutral form. All such preparations which retain their bioactivity when placed in suitable environmental conditions are included in the definition of the receptor proteins of the present invention. Further, the primary amino acid sequence of such proteins may be argumented by derivation using sugar moieties or by other supplementary molecules such as lipids, phosphate, acetyl groups and the like. Such modifications are included in the definition of the receptor proteins of the present invention so long as the bioactivity of the protein is not destroyed. It is expected, of course, that such modifications may quantitatively or qualitatively affect the bioactivity by either enhancing or diminishing the activity of the protein. Further, individual amino acid residues in the chain may be modified by oxidation, reduction, or other derivatization, and the receptor proteins of the present invention may be cleaved to obtain fragments which retain bioactivity. Such alterations which do not destroy bioactivity do not remove such receptor proteins from the definition. Finally modifications to the primary structure itself by deletion, addition, or alteration of the amino acids incorporated into the sequence during translation can be made without destroying the activity of the receptor proteins of the present invention. The present invention will hereinafter be described in more detail with the following Examples. It is understood of course that these Examples are not intended to limit the scope of the invention. Transformant E. coli JM109/pUC18 obtained in Example 1 described below was deposited with the Fermentation Research Institute, the Agency of Industrial Science and Technology, the Ministry of International Trade and Industry, Japan (FRI) under the accession number FERM BP-3127 on Oct. 9, 1990. This microorganism was deposited with the Institute for Fermentation, Osaka, Japan (IFO) under the accession number IFO 15096 on Oct. 11, 1990. Transformants E. coli DH1/pHLHR(UEX2) and E. coli JM109pHLHR(GEX-3X) obtained in Example 2 described below were deposited with the Fermentation Research Institute, the Agency of Industrial Science and Technology, the Ministry of International Trade and Industry, Japan (FRI) under the accession number FERM BP-3545 and FERM BP-3544 respectively on Aug. 29, 1991. EXAMPLE 1 (1) Preparation of a Human Ovary-Derived cDNA Library Total RNA was extracted from the human ovary by the guanidine thiocyanate method, and then mRNA was purified by use of an oligo(dt) cellulose column (Type 7, Pharmacia). Using a cDNA synthesizing kit (Pharmacia), cDNA was synthesized from about 2 μg of purified mRNA. The terminus of this cDNA was rendered flush with T4 DNA polymerase, followed by addition of an EcoRI adapter. This cDNA was bound to a λgt10 vector, and in vitro packaging was carried out by use of a packaging kit (Gigapack Gold, Stratagene). This library contained 1×10 6 independent recombinants, and was proliferated. (2) Purification of a Probe A cDNA library was prepared from the rat ovary in a manner similar to that described above, and inserted into a λZaPII vector (Stratagene). A rat LH/hCG receptor was cloned therefrom to isolate clones Zap3-5-1 (2.8 kb). The clones were labeled using the random primer method (Amersham), and used as a probe. (3) Screening A λgt10 cDNA library phage solution of 5×10 4 plaque forming units (pfu) was mixed with 500 μl of C600hfl (cultivated overnight), and the mixture was incubated at 37° C. for 15 minutes. Then, 8 ml of 0.75% agarose (Nippon Gene) LB was added thereto, and the mixture was inoculated on a 1.5% agar LB plate (15 cm dish). A nitrocellulose filter (Hybond-N, Amersham) was placed on the plate on which plaques were formed, and DNA was fixed. Subsequently, the filter was prehybridized at 65° C. for 1 to 2 hours in a solution prepared by adding 0.1% bovine serum albumin (BSA), polyvinylpyrrolidone, Ficoll 400 (Pharmacia), 5% pyrophosphoric acid and 0.1% SDS to 6×SSC (0.15 M NaCl, 0.015 M sodium citrate, pH 7.0). On hybridization, the probe was added to 200,000 cpm/ml as a guide. The filter was washed with 6×SSC at 42° C. for 15 minutes, and subsequently with 0.1×SSC at 65° C. for 10 minutes. Then, the filter was subjected to autoradiography at −70° C. (4) Analysis of DNA Sequence Some clones were identified, and the longest was selected from these clones for sequence analysis. This clone was subcloned into pUC18 (Takara), and E. coli JM109 was transformed with the resulting plasmid to yield transformant E. coli JM109/pUC18 (FERM BP-3127). This transformant was further shaved off stepwise by exonuclease digestion to prepare long to short single stranded DNA fragments. Sequence analysis was carried out by the dideoxy chain terminal method using a 7DEAZA sequencing kit. Electrophoresis was carried out by use of a LKB2010 Macrophor sequencing system. The SDC Genetyx software was used for data analysis. FIG. 1 shows the nucleotide sequence (SEQ ID NO:1) of the DNA of the human LH/hCG receptor protein, as well as the amino acid sequence deduced therefrom. The nucleotide sequence obtained in the present invention has additional 8 DNAs (−8 to −1) prior to N-terminus of the nucleotide sequence of SEQ ID NO:1. EXAMPLE 2 Expression of Human LH/HCG Receptor Protein (sometimes referred to herein as HLHR protein) (1) The HLHR cDNA clones obtained in Example 1 were used. The lac Z-HLHR fusion gene was obtained by cloning the 1400 bp EcoRI-Xba fragment coding for extracellular segment of the HLHR into the BamHI site of pUEX2. The lac Z-HLHR fusion construction was transformed into E. coli DH1 host to yield transformant E. coli DH1/pHLHR(UEX2) (FERM BP-3545). For preparation of lacZ-HLHR fusion protein, the transformant was cultivated in LB overnight at 30° C. 5 ml of the LB medium was innoculated with 50 μl of the overnight culture. After incubation of 2 hr at 30° C. with aeration and further incubation of 2 hr at 42° C., the cells were pelleted. The pellets were dissolved in a SDS-polyacrylamide gel electrophoresis (PAGE) sample buffer. The solution was subjected to 5% SDS-PAGE. E. coli transformed with pUEX2 vector was similarlly subjected to 5% SDS-PAGE. After electrophoresis, the gel was stained with Coomassie Blue. The result is shown in FIG. 3 . Lane 1 shows a molecular weight marker, lane 2 shows the case of pUEX2 vector and lane 3 shows the present transformant. A band at 110 kda of lane 2 disappears and a new band at 159 kda appears. The result of the electrophoresis and analysis of the nucleotide sequence show the expression of HLHR protein. (2) The GST (glutathion S-transferase) -HLHR fusion gene was obtained by cloning the 1400 bp EcoRI-Xba fragment coding for extracellular segment of the HLHR into the BamHI site of pGEX-3X(Pharmacia). The GST-HLHR fusion construction was transformed into E. coli JM 109 host to yield E. coli JM109/pHLHR(GEX-3X) (FERM BP-3544). The transformant was cultivated in LB overnight at 30° C. The overnight culture of JM 109 was diluted 1:10 in 500 ml of fresh medium and cultivated for 1 hr at 37° C. before adding IPTG to 0.1 mM. After further 7 hr culture, the cells were pelleted. The pellets were dissolved in a SDS-polyacrylamide gel electrophoresis (PAGE) sample buffer. The solution was subjected to 10% SDS-PAGE. E. coli transformed with pGEX-3X vector was similarily subjected to 10% SDS-PAGE. After electrophoresis, the gel was stained with Coomassie Blue. The result is shown in FIG. 4 . Lane 1 shows a molecular weight marker, lane 2 shows the case of pGEX-3X vector and lane 3 shows the present transformant. A band at 26 kda of lane 2 disappears and a new band at 75 kda appears. The result of the electrophoresis and analysis of the nucleotide sequence show the expression of HLHR protein. (3) Functional Expression of HLHR The expression vector pCHLHR was constructed by introducing the entire coding region of the cloned cDNA and additional flunking regions contained on an RcoRI fragment (2995 bp) into the pCDNA 1 vector. Human kidney 293 cells (ATCC CRL 1573) were maintained in Dulbecco's modified Eagle's medium containing 10% Fetal Calf serum in a humidified atmosphere containing 5% CO 2 . These cells were transiently transfected with PCHLHR, an expression vector encoding for the full-length human LH/hCG receptor, according to the procedure of calcium phosphate-mediated transfection. These cells were tested for their response ability to hCG with an increase in cAMP levels. The result is shown in FIG. 5 . In FIG. 5, the points indicate the mean and the bars indicate the range of the data. The present invention has been described in detail, including the preferred embodiments thereof. However, it will be appreciated that those skilled in the art, upon consideration of the present disclosure, may make modifications and improvements on this invention and still be within the scope and spirit of this invention as set forth in the following claims. 10 2987 base pairs nucleic acid double linear cDNA to mRNA unknown CDS 1..2097 1 ATG AAG CAG CGG TTC TCG GCG CTG CAG CTG CTG AAG CTG CTG CTG CTG 48 Met Lys Gln Arg Phe Ser Ala Leu Gln Leu Leu Lys Leu Leu Leu Leu 1 5 10 15 CTG CAG CCG CCG CTG CCA CGA GCG CTG CGC GAG GCG CTC TGC CCT GAG 96 Leu Gln Pro Pro Leu Pro Arg Ala Leu Arg Glu Ala Leu Cys Pro Glu 20 25 30 CCC TGC AAC TGC GTG CCC GAC GGC GCC CTG CGC TGC CCC GGC CCC ACG 144 Pro Cys Asn Cys Val Pro Asp Gly Ala Leu Arg Cys Pro Gly Pro Thr 35 40 45 GCC GGT CTC ACT CGA CTA TCA CTT GCC TAC CTC CCT GTC AAA GTG ATC 192 Ala Gly Leu Thr Arg Leu Ser Leu Ala Tyr Leu Pro Val Lys Val Ile 50 55 60 CCA TCT CAA GCT TTC AGA GGA CTT AAT GAG GTC ATA AAA ATT GAA ATC 240 Pro Ser Gln Ala Phe Arg Gly Leu Asn Glu Val Ile Lys Ile Glu Ile 65 70 75 80 TCT CAG ATT GAT TCC CTG GAA AGG ATA GAA GCT AAT GCC TTT GAC AAC 288 Ser Gln Ile Asp Ser Leu Glu Arg Ile Glu Ala Asn Ala Phe Asp Asn 85 90 95 CTC CTC AAT TTG TCT GAA ATA CTG ATC CAG AAC ACC AAA AAT CTG AGA 336 Leu Leu Asn Leu Ser Glu Ile Leu Ile Gln Asn Thr Lys Asn Leu Arg 100 105 110 TAC ATT GAG CCC GGA GCA TTT ATA AAT CTT CCC GGA TTA AAA TAC TTG 384 Tyr Ile Glu Pro Gly Ala Phe Ile Asn Leu Pro Gly Leu Lys Tyr Leu 115 120 125 AGC ATC TGT AAC ACA GGC ATC AGA AAG TTT CCA GAT GTT ACG AAG GTC 432 Ser Ile Cys Asn Thr Gly Ile Arg Lys Phe Pro Asp Val Thr Lys Val 130 135 140 TTC TCC TCT GAA TCA AAT TTC ATT CTG GAA ATT TGT GAT AAC TTA CAC 480 Phe Ser Ser Glu Ser Asn Phe Ile Leu Glu Ile Cys Asp Asn Leu His 145 150 155 160 ATA ACC ACC ATA CCA GGA AAT GCT TTT CAA GGG ATG AAT AAT GAA TCT 528 Ile Thr Thr Ile Pro Gly Asn Ala Phe Gln Gly Met Asn Asn Glu Ser 165 170 175 GTA ACA CTC AAA CTA TAT GGA AAT GGA TTT GAA GAA GTA CAA AGT CAT 576 Val Thr Leu Lys Leu Tyr Gly Asn Gly Phe Glu Glu Val Gln Ser His 180 185 190 GCA TTC AAT GGG ACG ACA CTG ACT TCA CTG GAG CTA AAG GAA AAC GTA 624 Ala Phe Asn Gly Thr Thr Leu Thr Ser Leu Glu Leu Lys Glu Asn Val 195 200 205 CAT CTG GAG AAG ATG CAC AAT GGA GCC TTC CGT GGG GCC ACA GGG CCG 672 His Leu Glu Lys Met His Asn Gly Ala Phe Arg Gly Ala Thr Gly Pro 210 215 220 AAA ACC TTG GAT ATT TCT TCC ACC AAA TTG CAG GCC CTG CCG AGC TAT 720 Lys Thr Leu Asp Ile Ser Ser Thr Lys Leu Gln Ala Leu Pro Ser Tyr 225 230 235 240 GGC CTA GAG TCC ATT CAG AGG CTA ATT GCC ACG TCA TCC TAT TCT CTA 768 Gly Leu Glu Ser Ile Gln Arg Leu Ile Ala Thr Ser Ser Tyr Ser Leu 245 250 255 AAA AAA TTG CCA TCA AGA GAA ACA TTT GTC AAT CTC CTG GAG GCC ACG 816 Lys Lys Leu Pro Ser Arg Glu Thr Phe Val Asn Leu Leu Glu Ala Thr 260 265 270 TTG ACT TAC CCC AGC CAC TGC TGT GCT TTT AGA AAC TTG CCA ACA AAA 864 Leu Thr Tyr Pro Ser His Cys Cys Ala Phe Arg Asn Leu Pro Thr Lys 275 280 285 GAA CAG AAT TTT TCA CAT TCC ATT TCT GAA AAC TTT TCC AAA CAA TGT 912 Glu Gln Asn Phe Ser His Ser Ile Ser Glu Asn Phe Ser Lys Gln Cys 290 295 300 GAA AGC ACA GTA AGG AAA GTG AGT AAC AAA ACA CTT TAT TCT TCC ATG 960 Glu Ser Thr Val Arg Lys Val Ser Asn Lys Thr Leu Tyr Ser Ser Met 305 310 315 320 CTT GCT GAG AGT GAA CTG AGT GGC TGG GAC TAT GAA TAT GGT TTC TGC 1008 Leu Ala Glu Ser Glu Leu Ser Gly Trp Asp Tyr Glu Tyr Gly Phe Cys 325 330 335 TTA CCC AAG ACA CCC CGA TGT GCT CCT GAA CCA GAT GCT TTT AAT CCC 1056 Leu Pro Lys Thr Pro Arg Cys Ala Pro Glu Pro Asp Ala Phe Asn Pro 340 345 350 TGT GAA GAC ATT ATG GGC TAT GAC TTC CTT AGG GTC CTG ATT TGG CTG 1104 Cys Glu Asp Ile Met Gly Tyr Asp Phe Leu Arg Val Leu Ile Trp Leu 355 360 365 ATT AAT ATT CTA GCC ATC ATG GGA AAC ATG ACT GTT CTT TTT GTT CTC 1152 Ile Asn Ile Leu Ala Ile Met Gly Asn Met Thr Val Leu Phe Val Leu 370 375 380 CTG ACA AGT CGT TAC AAA CTT ACA GTG CCT CGT TTT CTC ATG TGC AAT 1200 Leu Thr Ser Arg Tyr Lys Leu Thr Val Pro Arg Phe Leu Met Cys Asn 385 390 395 400 CTC TCC TTT GCA GAC TTT TGC ATG GGG CTC TAT CTG CTG CTC ATA GCC 1248 Leu Ser Phe Ala Asp Phe Cys Met Gly Leu Tyr Leu Leu Leu Ile Ala 405 410 415 TCA GTT GAT TCC CAA ACC AAG GGC CAG TAC TAT AAC CAT GCC ATA GAC 1296 Ser Val Asp Ser Gln Thr Lys Gly Gln Tyr Tyr Asn His Ala Ile Asp 420 425 430 TGG CAG ACA GGG AGT GGG TGC AGC ACT GCT GGC TTT TTC ACT GTA TTC 1344 Trp Gln Thr Gly Ser Gly Cys Ser Thr Ala Gly Phe Phe Thr Val Phe 435 440 445 GCA AGT GAA CTT TCT GTC TAC ACC CTC ACC GTC ATC ACT CTA GAA AGA 1392 Ala Ser Glu Leu Ser Val Tyr Thr Leu Thr Val Ile Thr Leu Glu Arg 450 455 460 TGG CAC ACC ATC ACC TAT GCT ATT CAC CTG GAC CAA AAG CTG CGA TTA 1440 Trp His Thr Ile Thr Tyr Ala Ile His Leu Asp Gln Lys Leu Arg Leu 465 470 475 480 AGA CAT GCC ATT CTG ATT ATG CTT GGA GGA TGG CTC TTT TCT TCT CTA 1488 Arg His Ala Ile Leu Ile Met Leu Gly Gly Trp Leu Phe Ser Ser Leu 485 490 495 ATT GCT ATG TTG CCC CTT GTC GGT GTC AGC AAT TAC ATG AAG GTC AGT 1536 Ile Ala Met Leu Pro Leu Val Gly Val Ser Asn Tyr Met Lys Val Ser 500 505 510 ATT TGC TTC CCC ATG GAT GTG GAA ACC ACT CTC TCA CAA GTC TAT ATA 1584 Ile Cys Phe Pro Met Asp Val Glu Thr Thr Leu Ser Gln Val Tyr Ile 515 520 525 TTA ACC ATC CTG ATT CTC AAT GTG GTG GCC TTC TTC ATA ATT TGT GCT 1632 Leu Thr Ile Leu Ile Leu Asn Val Val Ala Phe Phe Ile Ile Cys Ala 530 535 540 TGC TAC ATT AAA ATT TAT TTT GCA GTT CGA AAC CCA GAA TTA ATG GCT 1680 Cys Tyr Ile Lys Ile Tyr Phe Ala Val Arg Asn Pro Glu Leu Met Ala 545 550 555 560 ACC AAT AAA GAT ACA AAG ATT GCT AAG AAA ATG GCA ATC CTC ATC TTC 1728 Thr Asn Lys Asp Thr Lys Ile Ala Lys Lys Met Ala Ile Leu Ile Phe 565 570 575 ACC GAT TTC ACC TGC ATG GCA CCT ATC TCT TTT TTT GCC ATC TCA GCT 1776 Thr Asp Phe Thr Cys Met Ala Pro Ile Ser Phe Phe Ala Ile Ser Ala 580 585 590 GCC TTC AAA GTA CCT CTT ATC ACA GTA ACC AAC TCT AAA GTT TTA CTG 1824 Ala Phe Lys Val Pro Leu Ile Thr Val Thr Asn Ser Lys Val Leu Leu 595 600 605 GTT CTT TTT TAT CCC ATC AAT TCT TGT GCC AAT CCA TTT CTG TAT GCA 1872 Val Leu Phe Tyr Pro Ile Asn Ser Cys Ala Asn Pro Phe Leu Tyr Ala 610 615 620 ATA TTC ACT AAG ACA TTC CAA AGA GAT TTC TTT CTT TTG CTG AGC AAA 1920 Ile Phe Thr Lys Thr Phe Gln Arg Asp Phe Phe Leu Leu Leu Ser Lys 625 630 635 640 TTT GGC TGC TGT AAA CGT CGG GCT GAA CTT TAT AGA AGG AAA GAT TTT 1968 Phe Gly Cys Cys Lys Arg Arg Ala Glu Leu Tyr Arg Arg Lys Asp Phe 645 650 655 TCA GCT TAC ACC TCC AAC TGC AAA AAT GGC TTC ACT GGA TCA AAT AAG 2016 Ser Ala Tyr Thr Ser Asn Cys Lys Asn Gly Phe Thr Gly Ser Asn Lys 660 665 670 CCT TCT CAA TCC ACC TTG AAG TTG TCC ACA TTG CAC TGT CAA GGT ACA 2064 Pro Ser Gln Ser Thr Leu Lys Leu Ser Thr Leu His Cys Gln Gly Thr 675 680 685 GCT CTC CTA GAC AAG ACT CGC TAC ACA GAG TGT TAACTGTTAC ATCAGTAA 2117 Ala Leu Leu Asp Lys Thr Arg Tyr Thr Glu Cys 690 695 GCATTATTGA ATTGTTCTTA AACCTGTAAA AAAAAATTAC CTGTACCAGT AATTTTAACA 2177 TAAAGGGTTG GATTTAGGAA ATTATTTATT TTTAGGTACA TTAGGCAAGA GACCTCTACC 2237 TAGTAGAAAG TGTAGTCTAT GACCACTGCC ACACGTAAAA ACTATTTGTC ATTGTTACAT 2297 GGCATAAATA TGAAGTTGAG AGTGTTTAGA AATTTTTATA GAAATTTTGA CACAGTAATT 2357 TTGTTTGATG AATCTTTTAA AAAACAGAGG AGGTATTTTG CATATCTTTT TTTCATTTTC 2417 GTAATTTGTA TTGCATTCTA TAAAAATATT AGTTCATAAC AGATCAGAAA TTTAAAATAA 2477 GGGGCTTTTT CCTCAGGTAG TTTGAAAAAC ACACTCTAGA GATGCACTGT TCAATTCGGT 2537 ACGCACTAGC CACATGTGGC TAAATTAAAA TTAAATAAAA TGAGAAATGT AGTTTCTCAG 2597 TTGCACTACG TTTCAAGTTC TCAATGGCTA CGTCAAGTTC TCAATGGCTA CGTGTGACTA 2657 GTGCTTACCA TACTGGACAG CACAGACACA GAATATTTTC ATCACCACAG AAAGTTCTAT 2717 CTGTTCTATT ATAGAGACTT TTATGTATGC CCTATCTGGA TTCTACTTAT TTATAATTTA 2777 AGGTAAACAT CTGAAAGCAC ATTTCAGCCT ATTTGCTTAG TGAAACATTA AGCTGTAGAC 2837 TGTAAACTCC TCGTGAGTAG GAACCCTGTC TCAGTGCATT TTGTTTTCCT GCTTCCTACC 2897 TCAAGATCTT GGCAATGGTA CACTACAAAT GTGCTGAGTT AGAATTACTC TGAAGTTATG 2957 AAACATATAA TGAAAACAAT TTTTCCGGCC 2987 699 amino acids amino acid linear protein unknown 2 Met Lys Gln Arg Phe Ser Ala Leu Gln Leu Leu Lys Leu Leu Leu Leu 1 5 10 15 Leu Gln Pro Pro Leu Pro Arg Ala Leu Arg Glu Ala Leu Cys Pro Glu 20 25 30 Pro Cys Asn Cys Val Pro Asp Gly Ala Leu Arg Cys Pro Gly Pro Thr 35 40 45 Ala Gly Leu Thr Arg Leu Ser Leu Ala Tyr Leu Pro Val Lys Val Ile 50 55 60 Pro Ser Gln Ala Phe Arg Gly Leu Asn Glu Val Ile Lys Ile Glu Ile 65 70 75 80 Ser Gln Ile Asp Ser Leu Glu Arg Ile Glu Ala Asn Ala Phe Asp Asn 85 90 95 Leu Leu Asn Leu Ser Glu Ile Leu Ile Gln Asn Thr Lys Asn Leu Arg 100 105 110 Tyr Ile Glu Pro Gly Ala Phe Ile Asn Leu Pro Gly Leu Lys Tyr Leu 115 120 125 Ser Ile Cys Asn Thr Gly Ile Arg Lys Phe Pro Asp Val Thr Lys Val 130 135 140 Phe Ser Ser Glu Ser Asn Phe Ile Leu Glu Ile Cys Asp Asn Leu His 145 150 155 160 Ile Thr Thr Ile Pro Gly Asn Ala Phe Gln Gly Met Asn Asn Glu Ser 165 170 175 Val Thr Leu Lys Leu Tyr Gly Asn Gly Phe Glu Glu Val Gln Ser His 180 185 190 Ala Phe Asn Gly Thr Thr Leu Thr Ser Leu Glu Leu Lys Glu Asn Val 195 200 205 His Leu Glu Lys Met His Asn Gly Ala Phe Arg Gly Ala Thr Gly Pro 210 215 220 Lys Thr Leu Asp Ile Ser Ser Thr Lys Leu Gln Ala Leu Pro Ser Tyr 225 230 235 240 Gly Leu Glu Ser Ile Gln Arg Leu Ile Ala Thr Ser Ser Tyr Ser Leu 245 250 255 Lys Lys Leu Pro Ser Arg Glu Thr Phe Val Asn Leu Leu Glu Ala Thr 260 265 270 Leu Thr Tyr Pro Ser His Cys Cys Ala Phe Arg Asn Leu Pro Thr Lys 275 280 285 Glu Gln Asn Phe Ser His Ser Ile Ser Glu Asn Phe Ser Lys Gln Cys 290 295 300 Glu Ser Thr Val Arg Lys Val Ser Asn Lys Thr Leu Tyr Ser Ser Met 305 310 315 320 Leu Ala Glu Ser Glu Leu Ser Gly Trp Asp Tyr Glu Tyr Gly Phe Cys 325 330 335 Leu Pro Lys Thr Pro Arg Cys Ala Pro Glu Pro Asp Ala Phe Asn Pro 340 345 350 Cys Glu Asp Ile Met Gly Tyr Asp Phe Leu Arg Val Leu Ile Trp Leu 355 360 365 Ile Asn Ile Leu Ala Ile Met Gly Asn Met Thr Val Leu Phe Val Leu 370 375 380 Leu Thr Ser Arg Tyr Lys Leu Thr Val Pro Arg Phe Leu Met Cys Asn 385 390 395 400 Leu Ser Phe Ala Asp Phe Cys Met Gly Leu Tyr Leu Leu Leu Ile Ala 405 410 415 Ser Val Asp Ser Gln Thr Lys Gly Gln Tyr Tyr Asn His Ala Ile Asp 420 425 430 Trp Gln Thr Gly Ser Gly Cys Ser Thr Ala Gly Phe Phe Thr Val Phe 435 440 445 Ala Ser Glu Leu Ser Val Tyr Thr Leu Thr Val Ile Thr Leu Glu Arg 450 455 460 Trp His Thr Ile Thr Tyr Ala Ile His Leu Asp Gln Lys Leu Arg Leu 465 470 475 480 Arg His Ala Ile Leu Ile Met Leu Gly Gly Trp Leu Phe Ser Ser Leu 485 490 495 Ile Ala Met Leu Pro Leu Val Gly Val Ser Asn Tyr Met Lys Val Ser 500 505 510 Ile Cys Phe Pro Met Asp Val Glu Thr Thr Leu Ser Gln Val Tyr Ile 515 520 525 Leu Thr Ile Leu Ile Leu Asn Val Val Ala Phe Phe Ile Ile Cys Ala 530 535 540 Cys Tyr Ile Lys Ile Tyr Phe Ala Val Arg Asn Pro Glu Leu Met Ala 545 550 555 560 Thr Asn Lys Asp Thr Lys Ile Ala Lys Lys Met Ala Ile Leu Ile Phe 565 570 575 Thr Asp Phe Thr Cys Met Ala Pro Ile Ser Phe Phe Ala Ile Ser Ala 580 585 590 Ala Phe Lys Val Pro Leu Ile Thr Val Thr Asn Ser Lys Val Leu Leu 595 600 605 Val Leu Phe Tyr Pro Ile Asn Ser Cys Ala Asn Pro Phe Leu Tyr Ala 610 615 620 Ile Phe Thr Lys Thr Phe Gln Arg Asp Phe Phe Leu Leu Leu Ser Lys 625 630 635 640 Phe Gly Cys Cys Lys Arg Arg Ala Glu Leu Tyr Arg Arg Lys Asp Phe 645 650 655 Ser Ala Tyr Thr Ser Asn Cys Lys Asn Gly Phe Thr Gly Ser Asn Lys 660 665 670 Pro Ser Gln Ser Thr Leu Lys Leu Ser Thr Leu His Cys Gln Gly Thr 675 680 685 Ala Leu Leu Asp Lys Thr Arg Tyr Thr Glu Cys 690 695 700 amino acids amino acid linear protein unknown 3 Met Gly Arg Arg Val Pro Ala Leu Arg Gln Leu Leu Val Leu Ala Val 1 5 10 15 Leu Leu Leu Lys Pro Ser Gln Leu Gln Ser Arg Glu Leu Ser Gly Ser 20 25 30 Arg Cys Pro Glu Pro Cys Asp Cys Ala Pro Asp Gly Ala Leu Arg Cys 35 40 45 Pro Gly Pro Arg Ala Gly Leu Ala Arg Leu Ser Leu Thr Tyr Leu Pro 50 55 60 Val Lys Val Ile Pro Ser Gln Ala Phe Arg Gly Leu Asn Glu Val Val 65 70 75 80 Lys Ile Glu Ile Ser Gln Ser Asp Ser Leu Glu Arg Ile Glu Ala Asn 85 90 95 Ala Phe Asp Asn Leu Leu Asn Leu Ser Glu Leu Leu Ile Gln Asn Thr 100 105 110 Lys Asn Leu Leu Tyr Ile Glu Pro Gly Ala Phe Thr Asn Leu Pro Arg 115 120 125 Leu Lys Tyr Leu Ser Ile Cys Asn Thr Gly Ile Arg Thr Leu Pro Asp 130 135 140 Val Thr Lys Ile Ser Ser Ser Glu Phe Asn Phe Ile Leu Glu Ile Cys 145 150 155 160 Asp Asn Leu His Ile Thr Thr Ile Pro Gly Asn Ala Phe Gln Gly Met 165 170 175 Asn Asn Glu Ser Val Thr Leu Lys Leu Tyr Gly Asn Gly Phe Glu Glu 180 185 190 Val Gln Ser His Ala Phe Asn Gly Thr Thr Leu Ile Ser Leu Glu Leu 195 200 205 Lys Glu Asn Ile Tyr Leu Glu Lys Met His Ser Gly Ala Phe Gln Gly 210 215 220 Ala Thr Gly Pro Ser Ile Leu Asp Ile Ser Ser Thr Lys Leu Gln Ala 225 230 235 240 Leu Pro Ser His Gly Leu Glu Ser Ile Gln Thr Leu Ile Ala Leu Ser 245 250 255 Ser Tyr Ser Leu Lys Thr Leu Pro Ser Lys Glu Lys Phe Thr Ser Leu 260 265 270 Leu Val Ala Thr Leu Thr Tyr Pro Ser His Cys Cys Ala Phe Arg Asn 275 280 285 Leu Pro Lys Lys Glu Gln Asn Phe Ser Phe Ser Ile Phe Glu Asn Phe 290 295 300 Ser Lys Gln Cys Glu Ser Thr Val Arg Lys Ala Asp Asn Glu Thr Leu 305 310 315 320 Tyr Ser Ala Ile Phe Glu Glu Asn Glu Leu Ser Gly Trp Asp Tyr Asp 325 330 335 Tyr Gly Phe Cys Ser Pro Lys Thr Leu Gln Cys Ala Pro Glu Pro Asp 340 345 350 Ala Phe Asn Pro Cys Glu Asp Ile Met Gly Tyr Ala Phe Leu Arg Val 355 360 365 Leu Ile Trp Leu Ile Asn Ile Leu Ala Ile Phe Gly Asn Leu Thr Val 370 375 380 Leu Phe Val Leu Leu Thr Ser Arg Tyr Lys Leu Thr Val Pro Arg Phe 385 390 395 400 Leu Met Cys Asn Leu Ser Phe Ala Asp Phe Cys Met Gly Leu Tyr Leu 405 410 415 Leu Leu Ile Ala Ser Val Asp Ser Gln Thr Lys Gly Gln Tyr Tyr Asn 420 425 430 His Ala Ile Asp Trp Gln Thr Gly Ser Gly Cys Gly Ala Ala Gly Phe 435 440 445 Phe Thr Val Phe Ala Ser Glu Leu Ser Val Tyr Thr Leu Thr Val Ile 450 455 460 Thr Leu Glu Arg Trp His Thr Ile Thr Tyr Ala Val Gln Leu Asp Gln 465 470 475 480 Lys Leu Arg Leu Arg His Ala Ile Pro Ile Met Leu Gly Gly Trp Leu 485 490 495 Phe Ser Thr Leu Ile Ala Thr Met Pro Leu Val Gly Ile Ser Asn Tyr 500 505 510 Met Lys Val Ser Ile Cys Leu Pro Met Asp Val Glu Ser Thr Leu Ser 515 520 525 Gln Val Tyr Ile Leu Ser Ile Leu Ile Leu Asn Val Val Ala Phe Val 530 535 540 Val Ile Cys Ala Cys Tyr Ile Arg Ile Tyr Phe Ala Val Gln Asn Pro 545 550 555 560 Glu Leu Thr Ala Pro Asn Lys Asp Thr Lys Ile Ala Lys Lys Met Ala 565 570 575 Ile Leu Ile Phe Thr Asp Phe Thr Cys Met Ala Pro Ile Ser Phe Phe 580 585 590 Ala Ile Ser Ala Ala Phe Lys Val Pro Leu Ile Thr Val Thr Asn Ser 595 600 605 Lys Ile Leu Leu Val Leu Phe Tyr Pro Val Asn Ser Cys Ala Asn Pro 610 615 620 Phe Leu Tyr Ala Ile Phe Thr Lys Ala Phe Gln Arg Asp Phe Leu Leu 625 630 635 640 Leu Leu Ser Arg Phe Gly Cys Cys Lys Arg Arg Ala Glu Leu Tyr Arg 645 650 655 Arg Lys Glu Phe Ser Ala Tyr Thr Ser Asn Cys Lys Asn Gly Phe Pro 660 665 670 Gly Ala Ser Lys Pro Ser Gln Ala Thr Leu Lys Leu Ser Thr Val His 675 680 685 Cys Gln Gln Pro Ile Pro Pro Arg Ala Leu Thr His 690 695 700 696 amino acids amino acid linear protein unknown 4 Met Arg Arg Arg Ser Leu Ala Leu Arg Leu Leu Leu Ala Leu Leu Leu 1 5 10 15 Leu Pro Pro Pro Leu Pro Gln Thr Leu Leu Gly Ala Pro Cys Pro Glu 20 25 30 Pro Cys Ser Cys Arg Pro Asp Gly Ala Leu Arg Cys Pro Gly Pro Arg 35 40 45 Ala Gly Leu Ser Arg Leu Ser Leu Thr Tyr Leu Thr Ile Lys Val Ile 50 55 60 Pro Ser Gln Ala Phe Arg Gly Leu Asn Glu Val Val Lys Ile Glu Ile 65 70 75 80 Ser Gln Ser Asp Ser Leu Glu Lys Ile Glu Ala Asn Ala Phe Asp Asn 85 90 95 Leu Leu Asn Leu Ser Glu Ile Leu Ile Gln Asn Thr Lys Asn Leu Val 100 105 110 Tyr Ile Glu Pro Gly Ala Phe Thr Asn Leu Pro Arg Leu Lys Tyr Leu 115 120 125 Ser Ile Cys Asn Thr Gly Ile Arg Lys Leu Pro Asp Val Thr Lys Ile 130 135 140 Phe Ser Ser Glu Phe Asn Phe Ile Leu Glu Ile Cys Asp Asn Leu His 145 150 155 160 Ile Thr Thr Val Pro Ala Asn Ala Phe Gln Gly Met Asn Asn Glu Ser 165 170 175 Ile Thr Leu Lys Leu Tyr Gly Asn Gly Phe Glu Glu Ile Gln Ser His 180 185 190 Ala Phe Asn Gly Thr Thr Leu Ile Ser Leu Glu Leu Lys Glu Asn Ala 195 200 205 His Leu Lys Lys Met His Asn Asp Ala Phe Arg Gly Ala Arg Gly Pro 210 215 220 Ser Ile Leu Asp Ile Ser Ser Thr Lys Leu Gln Ala Leu Pro Ser Tyr 225 230 235 240 Gly Leu Glu Ser Ile Gln Thr Leu Ile Ala Thr Ser Ser Tyr Ser Leu 245 250 255 Lys Lys Leu Pro Ser Arg Glu Lys Phe Thr Asn Leu Leu Asp Ala Thr 260 265 270 Leu Thr Tyr Pro Ser His Cys Cys Ala Phe Arg Asn Leu Pro Thr Lys 275 280 285 Glu Gln Asn Phe Ser Phe Ser Ile Phe Lys Asn Phe Ser Lys Gln Cys 290 295 300 Glu Ser Thr Ala Arg Arg Pro Asn Asn Glu Thr Leu Tyr Ser Ala Ile 305 310 315 320 Phe Ala Glu Ser Glu Leu Ser Asp Trp Asp Tyr Asp Tyr Gly Phe Cys 325 330 335 Ser Pro Lys Thr Leu Gln Cys Ala Pro Glu Pro Asp Ala Phe Asn Pro 340 345 350 Cys Glu Asp Ile Met Gly Tyr Asp Phe Leu Arg Val Leu Ile Trp Leu 355 360 365 Ile Asn Ile Leu Ala Ile Met Gly Asn Val Thr Val Leu Phe Val Leu 370 375 380 Leu Thr Ser His Tyr Lys Leu Thr Val Pro Arg Phe Leu Met Cys Asn 385 390 395 400 Leu Ser Phe Ala Asp Phe Cys Met Gly Leu Tyr Leu Leu Leu Ile Ala 405 410 415 Ser Val Asp Ala Gln Thr Lys Gly Gln Tyr Tyr Asn His Ala Ile Asp 420 425 430 Trp Gln Thr Gly Asn Gly Cys Ser Val Ala Gly Phe Phe Thr Val Phe 435 440 445 Ala Ser Glu Leu Ser Val Tyr Thr Leu Thr Val Ile Thr Leu Glu Arg 450 455 460 Trp His Thr Ile Thr Tyr Ala Ile Gln Leu Asp Gln Lys Leu Arg Leu 465 470 475 480 Arg His Ala Ile Pro Ile Met Leu Gly Gly Trp Leu Phe Ser Thr Leu 485 490 495 Ile Ala Met Leu Pro Leu Val Gly Val Ser Ser Tyr Met Lys Val Ser 500 505 510 Ile Cys Leu Pro Met Asp Val Glu Thr Thr Leu Ser Gln Val Tyr Ile 515 520 525 Leu Thr Ile Leu Ile Leu Asn Val Val Ala Phe Ile Ile Ile Cys Ala 530 535 540 Cys Tyr Ile Lys Ile Tyr Phe Ala Val Gln Asn Pro Glu Leu Met Ala 545 550 555 560 Thr Asn Lys Asp Thr Lys Ile Ala Lys Lys Met Ala Val Leu Ile Phe 565 570 575 Thr Asp Phe Thr Cys Met Ala Pro Ile Ser Phe Phe Ala Ile Ser Ala 580 585 590 Ala Leu Lys Val Pro Leu Ile Thr Val Thr Asn Ser Lys Val Leu Leu 595 600 605 Val Leu Phe Tyr Pro Val Asn Ser Cys Ala Asn Pro Phe Leu Tyr Ala 610 615 620 Ile Phe Thr Lys Ala Phe Arg Arg Asp Phe Phe Leu Leu Leu Ser Lys 625 630 635 640 Ser Gly Cys Cys Lys His Gln Ala Glu Leu Tyr Arg Arg Lys Asp Phe 645 650 655 Ser Ala Tyr Cys Lys Asn Gly Phe Thr Gly Ser Asn Lys Pro Ser Gln 660 665 670 Ser Thr Leu Lys Leu Thr Thr Leu Gln Cys Gln Tyr Ser Thr Val Met 675 680 685 Asp Lys Thr Cys Tyr Lys Asp Cys 690 695 764 amino acids amino acid linear protein unknown 5 Met Arg Pro Ala Asp Leu Leu Gln Leu Val Leu Leu Leu Asp Leu Pro 1 5 10 15 Arg Asp Leu Gly Gly Met Gly Cys Ser Ser Pro Pro Cys Glu Cys His 20 25 30 Gln Glu Glu Asp Phe Arg Val Thr Cys Lys Asp Ile Gln Arg Ile Pro 35 40 45 Ser Leu Pro Pro Ser Thr Gln Thr Leu Lys Leu Ile Glu Thr His Leu 50 55 60 Arg Thr Ile Pro Ser His Ala Phe Ser Asn Leu Pro Asn Ile Ser Arg 65 70 75 80 Ile Tyr Val Ser Ile Asp Val Thr Leu Gln Gln Leu Glu Ser His Ser 85 90 95 Phe Tyr Asn Leu Ser Lys Val Thr His Ile Glu Ile Arg Asn Thr Arg 100 105 110 Asn Leu Thr Tyr Ile Asp Pro Asp Ala Leu Lys Glu Leu Pro Leu Leu 115 120 125 Lys Phe Leu Gly Ile Phe Asn Thr Gly Leu Lys Met Phe Pro Asp Leu 130 135 140 Thr Lys Val Tyr Ser Thr Asp Ile Phe Phe Ile Leu Glu Ile Thr Asp 145 150 155 160 Asn Pro Tyr Met Thr Ser Ile Pro Val Asn Ala Phe Gln Gly Leu Cys 165 170 175 Asn Glu Thr Leu Thr Leu Lys Leu Tyr Asn Asn Gly Phe Thr Ser Val 180 185 190 Gln Gly Tyr Ala Phe Asn Gly Thr Lys Leu Asp Ala Val Tyr Leu Asn 195 200 205 Lys Asn Lys Tyr Leu Thr Val Ile Tyr Lys Asp Ala Phe Gly Gly Val 210 215 220 Tyr Ser Gly Pro Ser Leu Leu Asp Val Ser Gln Thr Ser Val Thr Ala 225 230 235 240 Leu Pro Ser Lys Gly Leu Glu His Leu Lys Glu Leu Ile Ala Arg Asn 245 250 255 Thr Trp Thr Leu Lys Lys Leu Pro Leu Ser Leu Ser Phe Leu His Leu 260 265 270 Thr Arg Ala Asp Leu Ser Tyr Pro Ser His Cys Cys Ala Phe Lys Asn 275 280 285 Gln Lys Lys Ile Arg Gly Ile Leu Glu Ser Leu Met Cys Asn Glu Ser 290 295 300 Ser Met Gln Ser Leu Arg Gln Arg Lys Ser Val Asn Ala Leu Asn Ser 305 310 315 320 Pro Leu His Gln Glu Tyr Glu Glu Asn Leu Gly Asp Ser Ile Val Gly 325 330 335 Tyr Lys Glu Lys Ser Lys Phe Gln Asp Thr His Asn Asn Ala His Tyr 340 345 350 Tyr Val Phe Phe Glu Glu Gln Glu Asp Glu Ile Ile Gly Phe Gly Gln 355 360 365 Glu Leu Lys Asn Pro Gln Glu Glu Thr Leu Gln Ala Phe Asp Ser His 370 375 380 Tyr Asp Tyr Thr Ile Cys Gly Asp Ser Glu Asp Met Val Cys Thr Pro 385 390 395 400 Lys Ser Asp Glu Phe Asn Pro Cys Glu Asp Ile Met Gly Tyr Lys Phe 405 410 415 Leu Arg Ile Val Val Trp Phe Val Ser Leu Leu Ala Leu Leu Gly Asn 420 425 430 Val Phe Val Leu Leu Ile Leu Leu Thr Ser His Tyr Lys Leu Asn Val 435 440 445 Pro Arg Phe Leu Met Cys Asn Leu Ala Phe Ala Asp Phe Cys Met Gly 450 455 460 Met Tyr Leu Leu Leu Ile Ala Ser Val Asp Leu Tyr Thr His Ser Glu 465 470 475 480 Tyr Tyr Asn His Ala Ile Asp Trp Gln Thr Gly Pro Gly Cys Asn Thr 485 490 495 Ala Gly Phe Phe Thr Val Phe Ala Ser Glu Leu Ser Val Tyr Thr Leu 500 505 510 Thr Val Ile Thr Leu Glu Arg Trp Tyr Ala Ile Thr Phe Ala Met Arg 515 520 525 Leu Asp Arg Lys Met Arg Leu Arg His Ala Cys Ala Ile Met Val Gly 530 535 540 Gly Trp Val Cys Cys Phe Leu Leu Ala Leu Leu Pro Leu Val Gly Ile 545 550 555 560 Ser Ser Tyr Ala Lys Val Ser Ile Cys Leu Pro Met Asp Thr Glu Thr 565 570 575 Pro Leu Ala Leu Ala Tyr Ile Val Phe Val Leu Thr Leu Asn Ile Val 580 585 590 Ala Phe Val Ile Val Cys Cys Cys Tyr Val Lys Ile Tyr Ile Thr Val 595 600 605 Arg Asn Pro Gln Tyr Asn Pro Gly Asp Lys Asp Thr Lys Ile Ala Lys 610 615 620 Arg Met Ala Val Leu Ile Phe Thr Asp Phe Ile Cys Met Ala Pro Ile 625 630 635 640 Ser Phe Tyr Ala Leu Ser Ala Ile Leu Asn Lys Pro Leu Ile Thr Val 645 650 655 Ser Asn Ser Lys Ile Leu Leu Val Leu Phe Tyr Pro Leu Asn Ser Cys 660 665 670 Ala Asn Pro Phe Leu Tyr Ala Ile Phe Thr Lys Glu Phe Gln Arg Asp 675 680 685 Val Phe Ile Leu Leu Ser Lys Phe Gly Ile Cys Lys Arg Gln Ala Gln 690 695 700 Ala Tyr Arg Gly Gln Arg Val Pro Pro Lys Asn Ser Thr Asp Ile Gln 705 710 715 720 Val Gln Lys Val Thr His Glu Met Arg Gln Gly Leu His Asn Met Glu 725 730 735 Asp Val Tyr Glu Leu Ile Glu Lys Ser His Leu Thr Pro Lys Lys Gln 740 745 750 Gly Gln Ile Ser Glu Glu Tyr Met Gln Thr Val Leu 755 760 692 amino acids amino acid linear protein unknown 6 Met Ala Leu Leu Leu Val Ser Leu Leu Ala Phe Leu Gly Thr Gly Ser 1 5 10 15 Gly Cys His His Trp Leu Cys His Cys Ser Asn Arg Val Phe Leu Cys 20 25 30 Gln Asp Ser Lys Val Thr Glu Ile Pro Thr Asp Leu Pro Arg Asn Ala 35 40 45 Ile Glu Leu Arg Phe Val Leu Thr Lys Leu Arg Val Ile Pro Lys Gly 50 55 60 Ser Phe Ala Gly Phe Gly Asp Leu Glu Lys Ile Glu Ile Ser Gln Asn 65 70 75 80 Asp Val Leu Glu Val Ile Glu Ala Asp Val Phe Ser Asn Leu Pro Lys 85 90 95 Leu His Glu Ile Arg Ile Glu Lys Ala Asn Asn Leu Leu Tyr Ile Asn 100 105 110 Pro Glu Ala Phe Gln Asn Leu Pro Ser Leu Arg Tyr Leu Leu Ile Ser 115 120 125 Asn Thr Gly Ile Lys His Leu Pro Ala Val His Lys Ile Gln Ser Leu 130 135 140 Gln Lys Val Leu Leu Asp Ile Gln Asp Asn Ile Asn Ile His Ile Val 145 150 155 160 Ala Arg Asn Ser Phe Met Gly Leu Ser Phe Glu Ser Val Ile Leu Trp 165 170 175 Leu Ser Lys Asn Gly Ile Glu Glu Ile His Asn Cys Ala Phe Asn Gly 180 185 190 Thr Gln Leu Asp Glu Leu Asn Leu Ser Asp Asn Asn Asn Leu Glu Glu 195 200 205 Leu Pro Asn Asp Val Phe Gln Gly Ala Ser Gly Pro Val Ile Leu Asp 210 215 220 Ile Ser Arg Thr Lys Val His Ser Leu Pro Asn His Gly Leu Glu Asn 225 230 235 240 Leu Lys Lys Leu Arg Ala Arg Ser Thr Tyr Arg Leu Lys Lys Leu Pro 245 250 255 Asn Leu Asp Lys Phe Val Thr Leu Met Glu Ala Ser Leu Thr Tyr Pro 260 265 270 Ser His Cys Cys Ala Phe Ala Asn Leu Lys Arg Gln Ile Ser Glu Leu 275 280 285 His Pro Ile Cys Asn Lys Ser Ile Leu Arg Gln Asp Ile Asp Asp Met 290 295 300 Thr Gln Ile Gly Asp Gln Arg Val Ser Leu Ile Asp Asp Glu Pro Ser 305 310 315 320 Tyr Gly Lys Gly Ser Asp Met Met Tyr Asn Glu Phe Asp Tyr Asp Leu 325 330 335 Cys Asn Glu Val Val Asp Val Thr Cys Ser Pro Lys Pro Asp Ala Phe 340 345 350 Asn Pro Cys Glu Asp Ile Met Gly Tyr Asn Ile Leu Arg Val Leu Ile 355 360 365 Trp Phe Ile Ser Ile Leu Ala Ile Thr Gly Asn Thr Thr Val Leu Val 370 375 380 Val Leu Thr Thr Ser Gln Tyr Lys Leu Thr Val Pro Arg Phe Leu Met 385 390 395 400 Cys Asn Leu Ala Phe Ala Asp Leu Cys Ile Gly Ile Tyr Leu Leu Leu 405 410 415 Ile Ala Ser Val Asp Ile His Thr Lys Ser Gln Tyr His Asn Tyr Ala 420 425 430 Ile Asp Trp Gln Thr Gly Ala Gly Cys Asp Ala Ala Gly Phe Phe Thr 435 440 445 Val Phe Ala Ser Glu Leu Ser Val Tyr Thr Leu Thr Ala Ile Thr Leu 450 455 460 Glu Arg Trp His Thr Ile Thr His Ala Met Gln Leu Glu Cys Lys Val 465 470 475 480 Gln Leu Arg His Ala Ala Ser Val Met Val Leu Gly Trp Thr Phe Ala 485 490 495 Phe Ala Ala Ala Leu Phe Pro Ile Phe Gly Ile Ser Ser Tyr Met Lys 500 505 510 Val Ser Ile Cys Leu Pro Met Asp Ile Asp Ser Pro Leu Ser Gln Leu 515 520 525 Tyr Val Met Ala Leu Leu Val Leu Asn Val Leu Ala Phe Val Val Ile 530 535 540 Cys Gly Cys Tyr Thr His Ile Tyr Leu Thr Val Arg Asn Pro Thr Ile 545 550 555 560 Val Ser Ser Ser Ser Asp Thr Lys Ile Ala Lys Arg Met Ala Thr Leu 565 570 575 Ile Phe Thr Asp Phe Leu Cys Met Ala Pro Ile Ser Phe Phe Ala Ile 580 585 590 Ser Ala Ser Leu Lys Val Pro Leu Ile Thr Val Ser Lys Ala Lys Ile 595 600 605 Leu Leu Val Leu Phe Tyr Pro Ile Asn Ser Cys Ala Asn Pro Phe Leu 610 615 620 Tyr Ala Ile Phe Thr Lys Asn Phe Arg Arg Asp Phe Phe Ile Leu Leu 625 630 635 640 Ser Lys Phe Gly Cys Tyr Glu Met Gln Ala Gln Ile Tyr Arg Thr Glu 645 650 655 Thr Ser Ser Ala Thr His Asn Phe His Ala Arg Lys Ser His Cys Ser 660 665 670 Ser Ala Pro Arg Val Thr Asn Ser Tyr Val Leu Val Pro Leu Asn His 675 680 685 Ser Ser Gln Asn 690 636 amino acids amino acid linear protein unknown 7 Met Lys Gln Arg Phe Ser Ala Leu Gln Leu Leu Lys Leu Leu Leu Leu 1 5 10 15 Leu Gln Pro Pro Leu Pro Arg Ala Leu Arg Glu Ala Leu Cys Pro Glu 20 25 30 Pro Cys Asn Cys Val Pro Asp Gly Ala Leu Arg Cys Pro Gly Pro Thr 35 40 45 Ala Gly Leu Thr Arg Leu Ser Leu Ala Tyr Leu Pro Val Lys Val Ile 50 55 60 Pro Ser Gln Ala Phe Arg Gly Leu Asn Glu Val Ile Lys Ile Glu Ile 65 70 75 80 Ser Gln Ile Asp Ser Leu Glu Arg Ile Glu Ala Asn Ala Phe Asp Asn 85 90 95 Leu Leu Asn Leu Ser Glu Ile Leu Ile Gln Asn Thr Lys Asn Leu Arg 100 105 110 Tyr Ile Glu Pro Gly Ala Phe Ile Asn Leu Pro Gly Leu Lys Tyr Leu 115 120 125 Ser Ile Cys Asn Thr Gly Ile Arg Lys Phe Pro Asp Val Thr Lys Val 130 135 140 Phe Ser Ser Glu Ser Asn Phe Ile Leu Glu Ile Cys Asp Asn Leu His 145 150 155 160 Ile Thr Thr Ile Pro Gly Asn Ala Phe Gln Gly Met Asn Asn Glu Ser 165 170 175 Val Thr Leu Lys Leu Tyr Gly Asn Gly Phe Glu Glu Val Gln Ser His 180 185 190 Ala Phe Asn Gly Thr Thr Leu Thr Ser Leu Glu Leu Lys Glu Asn Val 195 200 205 His Leu Glu Lys Met His Asn Gly Ala Phe Arg Gly Ala Thr Gly Pro 210 215 220 Lys Thr Gln Asn Phe Ser His Ser Ile Ser Glu Asn Phe Ser Lys Gln 225 230 235 240 Cys Glu Ser Thr Val Arg Lys Val Ser Asn Lys Thr Leu Tyr Ser Ser 245 250 255 Met Leu Ala Glu Ser Glu Leu Ser Gly Trp Asp Tyr Glu Tyr Gly Phe 260 265 270 Cys Leu Pro Lys Thr Pro Arg Cys Ala Pro Glu Pro Asp Ala Phe Asn 275 280 285 Pro Cys Glu Asp Ile Met Gly Tyr Asp Phe Leu Arg Val Leu Ile Trp 290 295 300 Leu Ile Asn Ile Leu Ala Ile Met Gly Asn Met Thr Val Leu Phe Val 305 310 315 320 Leu Leu Thr Ser Arg Tyr Lys Leu Thr Val Pro Arg Phe Leu Met Cys 325 330 335 Asn Leu Ser Phe Ala Asp Phe Cys Met Gly Leu Tyr Leu Leu Leu Ile 340 345 350 Ala Ser Val Asp Ser Gln Thr Lys Gly Gln Tyr Tyr Asn His Ala Ile 355 360 365 Asp Trp Gln Thr Gly Ser Gly Cys Ser Thr Ala Gly Phe Phe Thr Val 370 375 380 Phe Ala Ser Glu Leu Ser Val Tyr Thr Leu Thr Val Ile Thr Leu Glu 385 390 395 400 Arg Trp His Thr Ile Thr Tyr Ala Ile His Leu Asp Gln Lys Leu Arg 405 410 415 Leu Arg His Ala Ile Leu Ile Met Leu Gly Gly Trp Leu Phe Ser Ser 420 425 430 Leu Ile Ala Met Leu Pro Leu Val Gly Val Ser Asn Tyr Met Lys Val 435 440 445 Ser Ile Cys Phe Pro Met Asp Val Glu Thr Thr Leu Ser Gln Val Tyr 450 455 460 Ile Leu Thr Ile Leu Ile Leu Asn Val Val Ala Phe Phe Ile Ile Cys 465 470 475 480 Ala Cys Tyr Ile Lys Ile Tyr Phe Ala Val Arg Asn Pro Glu Leu Met 485 490 495 Ala Thr Asn Lys Asp Thr Lys Ile Ala Lys Lys Met Ala Ile Leu Ile 500 505 510 Phe Thr Asp Phe Thr Cys Met Ala Pro Ile Ser Phe Phe Ala Ile Ser 515 520 525 Ala Ala Phe Lys Val Pro Leu Ile Thr Val Thr Asn Ser Lys Val Leu 530 535 540 Leu Val Leu Phe Tyr Pro Ile Asn Ser Cys Ala Asn Pro Phe Leu Tyr 545 550 555 560 Ala Ile Phe Thr Lys Thr Phe Gln Arg Asp Phe Phe Leu Leu Leu Ser 565 570 575 Lys Phe Gly Cys Cys Lys Arg Arg Ala Glu Leu Tyr Arg Arg Lys Asp 580 585 590 Phe Ser Ala Tyr Thr Ser Asn Cys Lys Asn Gly Phe Thr Gly Ser Asn 595 600 605 Lys Pro Ser Gln Ser Thr Leu Lys Leu Ser Thr Leu His Cys Gln Gly 610 615 620 Thr Ala Leu Leu Asp Lys Thr Arg Tyr Thr Glu Cys 625 630 635 611 amino acids amino acid linear protein unknown 8 Arg Glu Ala Leu Cys Pro Glu Pro Cys Asn Cys Val Pro Asp Gly Ala 1 5 10 15 Leu Arg Cys Pro Gly Pro Thr Ala Gly Leu Thr Arg Leu Ser Leu Ala 20 25 30 Tyr Leu Pro Val Lys Val Ile Pro Ser Gln Ala Phe Arg Gly Leu Asn 35 40 45 Glu Val Ile Lys Ile Glu Ile Ser Gln Ile Asp Ser Leu Glu Arg Ile 50 55 60 Glu Ala Asn Ala Phe Asp Asn Leu Leu Asn Leu Ser Glu Ile Leu Ile 65 70 75 80 Gln Asn Thr Lys Asn Leu Arg Tyr Ile Glu Pro Gly Ala Phe Ile Asn 85 90 95 Leu Pro Gly Leu Lys Tyr Leu Ser Ile Cys Asn Thr Gly Ile Arg Lys 100 105 110 Phe Pro Asp Val Thr Lys Val Phe Ser Ser Glu Ser Asn Phe Ile Leu 115 120 125 Glu Ile Cys Asp Asn Leu His Ile Thr Thr Ile Pro Gly Asn Ala Phe 130 135 140 Gln Gly Met Asn Asn Glu Ser Val Thr Leu Lys Leu Tyr Gly Asn Gly 145 150 155 160 Phe Glu Glu Val Gln Ser His Ala Phe Asn Gly Thr Thr Leu Thr Ser 165 170 175 Leu Glu Leu Lys Glu Asn Val His Leu Glu Lys Met His Asn Gly Ala 180 185 190 Phe Arg Gly Ala Thr Gly Pro Lys Thr Gln Asn Phe Ser His Ser Ile 195 200 205 Ser Glu Asn Phe Ser Lys Gln Cys Glu Ser Thr Val Arg Lys Val Ser 210 215 220 Asn Lys Thr Leu Tyr Ser Ser Met Leu Ala Glu Ser Glu Leu Ser Gly 225 230 235 240 Trp Asp Tyr Glu Tyr Gly Phe Cys Leu Pro Lys Thr Pro Arg Cys Ala 245 250 255 Pro Glu Pro Asp Ala Phe Asn Pro Cys Glu Asp Ile Met Gly Tyr Asp 260 265 270 Phe Leu Arg Val Leu Ile Trp Leu Ile Asn Ile Leu Ala Ile Met Gly 275 280 285 Asn Met Thr Val Leu Phe Val Leu Leu Thr Ser Arg Tyr Lys Leu Thr 290 295 300 Val Pro Arg Phe Leu Met Cys Asn Leu Ser Phe Ala Asp Phe Cys Met 305 310 315 320 Gly Leu Tyr Leu Leu Leu Ile Ala Ser Val Asp Ser Gln Thr Lys Gly 325 330 335 Gln Tyr Tyr Asn His Ala Ile Asp Trp Gln Thr Gly Ser Gly Cys Ser 340 345 350 Thr Ala Gly Phe Phe Thr Val Phe Ala Ser Glu Leu Ser Val Tyr Thr 355 360 365 Leu Thr Val Ile Thr Leu Glu Arg Trp His Thr Ile Thr Tyr Ala Ile 370 375 380 His Leu Asp Gln Lys Leu Arg Leu Arg His Ala Ile Leu Ile Met Leu 385 390 395 400 Gly Gly Trp Leu Phe Ser Ser Leu Ile Ala Met Leu Pro Leu Val Gly 405 410 415 Val Ser Asn Tyr Met Lys Val Ser Ile Cys Phe Pro Met Asp Val Glu 420 425 430 Thr Thr Leu Ser Gln Val Tyr Ile Leu Thr Ile Leu Ile Leu Asn Val 435 440 445 Val Ala Phe Phe Ile Ile Cys Ala Cys Tyr Ile Lys Ile Tyr Phe Ala 450 455 460 Val Arg Asn Pro Glu Leu Met Ala Thr Asn Lys Asp Thr Lys Ile Ala 465 470 475 480 Lys Lys Met Ala Ile Leu Ile Phe Thr Asp Phe Thr Cys Met Ala Pro 485 490 495 Ile Ser Phe Phe Ala Ile Ser Ala Ala Phe Lys Val Pro Leu Ile Thr 500 505 510 Val Thr Asn Ser Lys Val Leu Leu Val Leu Phe Tyr Pro Ile Asn Ser 515 520 525 Cys Ala Asn Pro Phe Leu Tyr Ala Ile Phe Thr Lys Thr Phe Gln Arg 530 535 540 Asp Phe Phe Leu Leu Leu Ser Lys Phe Gly Cys Cys Lys Arg Arg Ala 545 550 555 560 Glu Leu Tyr Arg Arg Lys Asp Phe Ser Ala Tyr Thr Ser Asn Cys Lys 565 570 575 Asn Gly Phe Thr Gly Ser Asn Lys Pro Ser Gln Ser Thr Leu Lys Leu 580 585 590 Ser Thr Leu His Cys Gln Gly Thr Ala Leu Leu Asp Lys Thr Arg Tyr 595 600 605 Thr Glu Cys 610 2022 base pairs nucleic acid double linear cDNA to mRNA unknown CDS 1..2022 9 CGC GAG GCG CTC TGC CCT GAG CCC TGC AAC TGC GTG CCC GAC GGC GCC 48 Arg Glu Ala Leu Cys Pro Glu Pro Cys Asn Cys Val Pro Asp Gly Ala 1 5 10 15 CTG CGC TGC CCC GGC CCC ACG GCC GGT CTC ACT CGA CTA TCA CTT GCC 96 Leu Arg Cys Pro Gly Pro Thr Ala Gly Leu Thr Arg Leu Ser Leu Ala 20 25 30 TAC CTC CCT GTC AAA GTG ATC CCA TCT CAA GCT TTC AGA GGA CTT AAT 144 Tyr Leu Pro Val Lys Val Ile Pro Ser Gln Ala Phe Arg Gly Leu Asn 35 40 45 GAG GTC ATA AAA ATT GAA ATC TCT CAG ATT GAT TCC CTG GAA AGG ATA 192 Glu Val Ile Lys Ile Glu Ile Ser Gln Ile Asp Ser Leu Glu Arg Ile 50 55 60 GAA GCT AAT GCC TTT GAC AAC CTC CTC AAT TTG TCT GAA ATA CTG ATC 240 Glu Ala Asn Ala Phe Asp Asn Leu Leu Asn Leu Ser Glu Ile Leu Ile 65 70 75 80 CAG AAC ACC AAA AAT CTG AGA TAC ATT GAG CCC GGA GCA TTT ATA AAT 288 Gln Asn Thr Lys Asn Leu Arg Tyr Ile Glu Pro Gly Ala Phe Ile Asn 85 90 95 CTT CCC GGA TTA AAA TAC TTG AGC ATC TGT AAC ACA GGC ATC AGA AAG 336 Leu Pro Gly Leu Lys Tyr Leu Ser Ile Cys Asn Thr Gly Ile Arg Lys 100 105 110 TTT CCA GAT GTT ACG AAG GTC TTC TCC TCT GAA TCA AAT TTC ATT CTG 384 Phe Pro Asp Val Thr Lys Val Phe Ser Ser Glu Ser Asn Phe Ile Leu 115 120 125 GAA ATT TGT GAT AAC TTA CAC ATA ACC ACC ATA CCA GGA AAT GCT TTT 432 Glu Ile Cys Asp Asn Leu His Ile Thr Thr Ile Pro Gly Asn Ala Phe 130 135 140 CAA GGG ATG AAT AAT GAA TCT GTA ACA CTC AAA CTA TAT GGA AAT GGA 480 Gln Gly Met Asn Asn Glu Ser Val Thr Leu Lys Leu Tyr Gly Asn Gly 145 150 155 160 TTT GAA GAA GTA CAA AGT CAT GCA TTC AAT GGG ACG ACA CTG ACT TCA 528 Phe Glu Glu Val Gln Ser His Ala Phe Asn Gly Thr Thr Leu Thr Ser 165 170 175 CTG GAG CTA AAG GAA AAC GTA CAT CTG GAG AAG ATG CAC AAT GGA GCC 576 Leu Glu Leu Lys Glu Asn Val His Leu Glu Lys Met His Asn Gly Ala 180 185 190 TTC CGT GGG GCC ACA GGG CCG AAA ACC TTG GAT ATT TCT TCC ACC AAA 624 Phe Arg Gly Ala Thr Gly Pro Lys Thr Leu Asp Ile Ser Ser Thr Lys 195 200 205 TTG CAG GCC CTG CCG AGC TAT GGC CTA GAG TCC ATT CAG AGG CTA ATT 672 Leu Gln Ala Leu Pro Ser Tyr Gly Leu Glu Ser Ile Gln Arg Leu Ile 210 215 220 GCC ACG TCA TCC TAT TCT CTA AAA AAA TTG CCA TCA AGA GAA ACA TTT 720 Ala Thr Ser Ser Tyr Ser Leu Lys Lys Leu Pro Ser Arg Glu Thr Phe 225 230 235 240 GTC AAT CTC CTG GAG GCC ACG TTG ACT TAC CCC AGC CAC TGC TGT GCT 768 Val Asn Leu Leu Glu Ala Thr Leu Thr Tyr Pro Ser His Cys Cys Ala 245 250 255 TTT AGA AAC TTG CCA ACA AAA GAA CAG AAT TTT TCA CAT TCC ATT TCT 816 Phe Arg Asn Leu Pro Thr Lys Glu Gln Asn Phe Ser His Ser Ile Ser 260 265 270 GAA AAC TTT TCC AAA CAA TGT GAA AGC ACA GTA AGG AAA GTG AGT AAC 864 Glu Asn Phe Ser Lys Gln Cys Glu Ser Thr Val Arg Lys Val Ser Asn 275 280 285 AAA ACA CTT TAT TCT TCC ATG CTT GCT GAG AGT GAA CTG AGT GGC TGG 912 Lys Thr Leu Tyr Ser Ser Met Leu Ala Glu Ser Glu Leu Ser Gly Trp 290 295 300 GAC TAT GAA TAT GGT TTC TGC TTA CCC AAG ACA CCC CGA TGT GCT CCT 960 Asp Tyr Glu Tyr Gly Phe Cys Leu Pro Lys Thr Pro Arg Cys Ala Pro 305 310 315 320 GAA CCA GAT GCT TTT AAT CCC TGT GAA GAC ATT ATG GGC TAT GAC TTC 1008 Glu Pro Asp Ala Phe Asn Pro Cys Glu Asp Ile Met Gly Tyr Asp Phe 325 330 335 CTT AGG GTC CTG ATT TGG CTG ATT AAT ATT CTA GCC ATC ATG GGA AAC 1056 Leu Arg Val Leu Ile Trp Leu Ile Asn Ile Leu Ala Ile Met Gly Asn 340 345 350 ATG ACT GTT CTT TTT GTT CTC CTG ACA AGT CGT TAC AAA CTT ACA GTG 1104 Met Thr Val Leu Phe Val Leu Leu Thr Ser Arg Tyr Lys Leu Thr Val 355 360 365 CCT CGT TTT CTC ATG TGC AAT CTC TCC TTT GCA GAC TTT TGC ATG GGG 1152 Pro Arg Phe Leu Met Cys Asn Leu Ser Phe Ala Asp Phe Cys Met Gly 370 375 380 CTC TAT CTG CTG CTC ATA GCC TCA GTT GAT TCC CAA ACC AAG GGC CAG 1200 Leu Tyr Leu Leu Leu Ile Ala Ser Val Asp Ser Gln Thr Lys Gly Gln 385 390 395 400 TAC TAT AAC CAT GCC ATA GAC TGG CAG ACA GGG AGT GGG TGC AGC ACT 1248 Tyr Tyr Asn His Ala Ile Asp Trp Gln Thr Gly Ser Gly Cys Ser Thr 405 410 415 GCT GGC TTT TTC ACT GTA TTC GCA AGT GAA CTT TCT GTC TAC ACC CTC 1296 Ala Gly Phe Phe Thr Val Phe Ala Ser Glu Leu Ser Val Tyr Thr Leu 420 425 430 ACC GTC ATC ACT CTA GAA AGA TGG CAC ACC ATC ACC TAT GCT ATT CAC 1344 Thr Val Ile Thr Leu Glu Arg Trp His Thr Ile Thr Tyr Ala Ile His 435 440 445 CTG GAC CAA AAG CTG CGA TTA AGA CAT GCC ATT CTG ATT ATG CTT GGA 1392 Leu Asp Gln Lys Leu Arg Leu Arg His Ala Ile Leu Ile Met Leu Gly 450 455 460 GGA TGG CTC TTT TCT TCT CTA ATT GCT ATG TTG CCC CTT GTC GGT GTC 1440 Gly Trp Leu Phe Ser Ser Leu Ile Ala Met Leu Pro Leu Val Gly Val 465 470 475 480 AGC AAT TAC ATG AAG GTC AGT ATT TGC TTC CCC ATG GAT GTG GAA ACC 1488 Ser Asn Tyr Met Lys Val Ser Ile Cys Phe Pro Met Asp Val Glu Thr 485 490 495 ACT CTC TCA CAA GTC TAT ATA TTA ACC ATC CTG ATT CTC AAT GTG GTG 1536 Thr Leu Ser Gln Val Tyr Ile Leu Thr Ile Leu Ile Leu Asn Val Val 500 505 510 GCC TTC TTC ATA ATT TGT GCT TGC TAC ATT AAA ATT TAT TTT GCA GTT 1584 Ala Phe Phe Ile Ile Cys Ala Cys Tyr Ile Lys Ile Tyr Phe Ala Val 515 520 525 CGA AAC CCA GAA TTA ATG GCT ACC AAT AAA GAT ACA AAG ATT GCT AAG 1632 Arg Asn Pro Glu Leu Met Ala Thr Asn Lys Asp Thr Lys Ile Ala Lys 530 535 540 AAA ATG GCA ATC CTC ATC TTC ACC GAT TTC ACC TGC ATG GCA CCT ATC 1680 Lys Met Ala Ile Leu Ile Phe Thr Asp Phe Thr Cys Met Ala Pro Ile 545 550 555 560 TCT TTT TTT GCC ATC TCA GCT GCC TTC AAA GTA CCT CTT ATC ACA GTA 1728 Ser Phe Phe Ala Ile Ser Ala Ala Phe Lys Val Pro Leu Ile Thr Val 565 570 575 ACC AAC TCT AAA GTT TTA CTG GTT CTT TTT TAT CCC ATC AAT TCT TGT 1776 Thr Asn Ser Lys Val Leu Leu Val Leu Phe Tyr Pro Ile Asn Ser Cys 580 585 590 GCC AAT CCA TTT CTG TAT GCA ATA TTC ACT AAG ACA TTC CAA AGA GAT 1824 Ala Asn Pro Phe Leu Tyr Ala Ile Phe Thr Lys Thr Phe Gln Arg Asp 595 600 605 TTC TTT CTT TTG CTG AGC AAA TTT GGC TGC TGT AAA CGT CGG GCT GAA 1872 Phe Phe Leu Leu Leu Ser Lys Phe Gly Cys Cys Lys Arg Arg Ala Glu 610 615 620 CTT TAT AGA AGG AAA GAT TTT TCA GCT TAC ACC TCC AAC TGC AAA AAT 1920 Leu Tyr Arg Arg Lys Asp Phe Ser Ala Tyr Thr Ser Asn Cys Lys Asn 625 630 635 640 GGC TTC ACT GGA TCA AAT AAG CCT TCT CAA TCC ACC TTG AAG TTG TCC 1968 Gly Phe Thr Gly Ser Asn Lys Pro Ser Gln Ser Thr Leu Lys Leu Ser 645 650 655 ACA TTG CAC TGT CAA GGT ACA GCT CTC CTA GAC AAG ACT CGC TAC ACA 2016 Thr Leu His Cys Gln Gly Thr Ala Leu Leu Asp Lys Thr Arg Tyr Thr 660 665 670 GAG TGT 2022 Glu Cys 674 amino acids amino acid linear protein unknown 10 Arg Glu Ala Leu Cys Pro Glu Pro Cys Asn Cys Val Pro Asp Gly Ala 1 5 10 15 Leu Arg Cys Pro Gly Pro Thr Ala Gly Leu Thr Arg Leu Ser Leu Ala 20 25 30 Tyr Leu Pro Val Lys Val Ile Pro Ser Gln Ala Phe Arg Gly Leu Asn 35 40 45 Glu Val Ile Lys Ile Glu Ile Ser Gln Ile Asp Ser Leu Glu Arg Ile 50 55 60 Glu Ala Asn Ala Phe Asp Asn Leu Leu Asn Leu Ser Glu Ile Leu Ile 65 70 75 80 Gln Asn Thr Lys Asn Leu Arg Tyr Ile Glu Pro Gly Ala Phe Ile Asn 85 90 95 Leu Pro Gly Leu Lys Tyr Leu Ser Ile Cys Asn Thr Gly Ile Arg Lys 100 105 110 Phe Pro Asp Val Thr Lys Val Phe Ser Ser Glu Ser Asn Phe Ile Leu 115 120 125 Glu Ile Cys Asp Asn Leu His Ile Thr Thr Ile Pro Gly Asn Ala Phe 130 135 140 Gln Gly Met Asn Asn Glu Ser Val Thr Leu Lys Leu Tyr Gly Asn Gly 145 150 155 160 Phe Glu Glu Val Gln Ser His Ala Phe Asn Gly Thr Thr Leu Thr Ser 165 170 175 Leu Glu Leu Lys Glu Asn Val His Leu Glu Lys Met His Asn Gly Ala 180 185 190 Phe Arg Gly Ala Thr Gly Pro Lys Thr Leu Asp Ile Ser Ser Thr Lys 195 200 205 Leu Gln Ala Leu Pro Ser Tyr Gly Leu Glu Ser Ile Gln Arg Leu Ile 210 215 220 Ala Thr Ser Ser Tyr Ser Leu Lys Lys Leu Pro Ser Arg Glu Thr Phe 225 230 235 240 Val Asn Leu Leu Glu Ala Thr Leu Thr Tyr Pro Ser His Cys Cys Ala 245 250 255 Phe Arg Asn Leu Pro Thr Lys Glu Gln Asn Phe Ser His Ser Ile Ser 260 265 270 Glu Asn Phe Ser Lys Gln Cys Glu Ser Thr Val Arg Lys Val Ser Asn 275 280 285 Lys Thr Leu Tyr Ser Ser Met Leu Ala Glu Ser Glu Leu Ser Gly Trp 290 295 300 Asp Tyr Glu Tyr Gly Phe Cys Leu Pro Lys Thr Pro Arg Cys Ala Pro 305 310 315 320 Glu Pro Asp Ala Phe Asn Pro Cys Glu Asp Ile Met Gly Tyr Asp Phe 325 330 335 Leu Arg Val Leu Ile Trp Leu Ile Asn Ile Leu Ala Ile Met Gly Asn 340 345 350 Met Thr Val Leu Phe Val Leu Leu Thr Ser Arg Tyr Lys Leu Thr Val 355 360 365 Pro Arg Phe Leu Met Cys Asn Leu Ser Phe Ala Asp Phe Cys Met Gly 370 375 380 Leu Tyr Leu Leu Leu Ile Ala Ser Val Asp Ser Gln Thr Lys Gly Gln 385 390 395 400 Tyr Tyr Asn His Ala Ile Asp Trp Gln Thr Gly Ser Gly Cys Ser Thr 405 410 415 Ala Gly Phe Phe Thr Val Phe Ala Ser Glu Leu Ser Val Tyr Thr Leu 420 425 430 Thr Val Ile Thr Leu Glu Arg Trp His Thr Ile Thr Tyr Ala Ile His 435 440 445 Leu Asp Gln Lys Leu Arg Leu Arg His Ala Ile Leu Ile Met Leu Gly 450 455 460 Gly Trp Leu Phe Ser Ser Leu Ile Ala Met Leu Pro Leu Val Gly Val 465 470 475 480 Ser Asn Tyr Met Lys Val Ser Ile Cys Phe Pro Met Asp Val Glu Thr 485 490 495 Thr Leu Ser Gln Val Tyr Ile Leu Thr Ile Leu Ile Leu Asn Val Val 500 505 510 Ala Phe Phe Ile Ile Cys Ala Cys Tyr Ile Lys Ile Tyr Phe Ala Val 515 520 525 Arg Asn Pro Glu Leu Met Ala Thr Asn Lys Asp Thr Lys Ile Ala Lys 530 535 540 Lys Met Ala Ile Leu Ile Phe Thr Asp Phe Thr Cys Met Ala Pro Ile 545 550 555 560 Ser Phe Phe Ala Ile Ser Ala Ala Phe Lys Val Pro Leu Ile Thr Val 565 570 575 Thr Asn Ser Lys Val Leu Leu Val Leu Phe Tyr Pro Ile Asn Ser Cys 580 585 590 Ala Asn Pro Phe Leu Tyr Ala Ile Phe Thr Lys Thr Phe Gln Arg Asp 595 600 605 Phe Phe Leu Leu Leu Ser Lys Phe Gly Cys Cys Lys Arg Arg Ala Glu 610 615 620 Leu Tyr Arg Arg Lys Asp Phe Ser Ala Tyr Thr Ser Asn Cys Lys Asn 625 630 635 640 Gly Phe Thr Gly Ser Asn Lys Pro Ser Gln Ser Thr Leu Lys Leu Ser 645 650 655 Thr Leu His Cys Gln Gly Thr Ala Leu Leu Asp Lys Thr Arg Tyr Thr 660 665 670 Glu Cys

Disclosed are (1) a human luteinizing hormone-human chorionic gonadotropin receptor protein, (2) a DNA comprising a cDNA segment coding for a human luteinizing hormone-human chorionic gonadotropin receptor protein, (SEQ ID NO:2) (3) a transformant carrying a DNA comprising a cDNA segment (SEQ ID NO:1) coding for a human luteinizing hormone-human chorionic gonadotropin receptor protein, and (4) a method for preparing a human luteinizing hormone-human chorionic gonadotropin receptor protein which comprises cultivating the transformant described in (3), accumulating a protein (SEQ ID NO:2) in a culture broth, and collecting the same, whereby the structure and properties of the receptor protein are made clear and the mass production thereof by recombinant technology is pioneered.

RELATED APPLICATIONS [0001] This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. JP2009-072646 filed on Mar. 24, 2009, the entire content of which is hereby incorporated by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an animal blood cell measuring apparatus. [0004] 2. Description of the Related Art [0005] In making diagnoses on animals, counting reticulocytes is useful for diagnosing animals with, for example, anemia. At veterinary hospitals, currently, counting of red blood cells or white blood cells is often automatically performed using analyzers; however, reticulocytes are visually counted in general. [0006] United States Patent Publication No. 2006/0004530 discloses an analyzer for automatically counting animal reticulocytes. The analyzer of United States Patent Publication No. 2006/0004530 receives the selection of an animal species to be analyzed, and counts blood cells based on analysis conditions corresponding to the received selection of the animal species. Here, blood cells to be counted include reticulocytes in addition to red blood cells, white blood cells, and the like. [0007] Reticulocytes of some animal species consist of a single type of reticulocytes. However, for example, reticulocytes in felines consist of a plurality of types of reticulocytes including punctate and aggregate reticulocytes. Counting aggregate reticulocytes is useful when diagnosing animal species with anemia, whose reticulocytes consist of a plurality of types of reticulocytes. For example, in the case of felines, the number of punctate reticulocytes reaches a peak within 10 to 20 days after an episode of acute blood loss. Thereafter, the punctate reticulocytes disappear over approximately four weeks. Whereas, the number of aggregate reticulocytes reaches a peak within 4 to 7 days after the episode of acute blood loss. Accordingly, counting aggregate reticulocytes, the number of which reaches a peak at an earlier stage than the punctate reticulocytes, is useful, for example, for determining the degree of recovery from anemia (i.e., useful for determining the effect of medication). [0008] As mentioned above, there are known analyzers that automatically count reticulocytes. However, United States Patent Publication No. 2006/0004530 does not give a description in relation to counting only aggregate reticulocytes among reticulocytes consisting of a plurality of types of reticulocytes. Therefore, even if the analyzer disclosed in United States Patent Publication No. 2006/0004530 is used, aggregate reticulocytes have to be visually counted, which imposes a substantial burden on veterinarians and laboratory technicians. SUMMARY OF THE INVENTION [0009] A first aspect of the present invention is an animal blood cell measuring apparatus comprising: a specimen preparation section for preparing a measurement specimen from blood of an animal; a characteristic information obtaining section for obtaining characteristic information indicating a characteristic of the measurement specimen, from the measurement specimen prepared by the specimen preparation section; and a controller configured for performing operations comprising: (a) classifying aggregate reticulocytes contained in the blood from other blood cells, based on the characteristic information obtained by the characteristic information obtaining section; and (b) outputting information regarding a number of the classified aggregate reticulocytes. [0010] A second aspect of the present invention is an animal blood cell measuring apparatus comprising: a specimen preparation section for preparing a measurement specimen from blood of an animal; a characteristic information obtaining section for obtaining characteristic information indicating a characteristic of the measurement specimen, from the measurement specimen prepared by the specimen preparation section; an aggregate-type classifying section for classifying aggregate reticulocytes contained in the blood from other blood cells, based on the characteristic information obtained by the characteristic information obtaining section; and an output section for outputting information regarding a number of the aggregate reticulocytes classified by the aggregate-type classifying section. [0011] A third aspect of the present invention is animal blood cell measuring apparatus, comprising: a specimen preparation section for preparing a measurement specimen from blood of an animal; a characteristic information obtaining section for obtaining characteristic information indicating a characteristic of the measurement specimen from the measurement specimen prepared by the specimen preparation section; a selector for selecting an animal species to be measured, from at least a first animal species and a second animal species; and a controller configured for performing operations, comprising: (a) receiving a selection of the animal species selected by the selector; (b) classifying reticulocytes contained in the blood from other blood cells based on the characteristic information obtained by the characteristic information obtaining section, in response to the received selection of the animal species; and (c) outputting information regarding a number of the classified reticulocytes. BRIEF DESCRIPTION OF THE DRAWINGS [0012] FIG. 1 is a front view showing a schematic structure of a blood cell measuring apparatus according to an embodiment of the present invention; [0013] FIG. 2 is a perspective external view of a measurement unit according to the embodiment; [0014] FIG. 3 is a perspective view showing an internal structure of the measurement unit according to the embodiment; [0015] FIG. 4 is a side view showing the internal structure of the measurement unit according to the embodiment; [0016] FIG. 5 is a block diagram showing a configuration of the measurement unit according to the embodiment; [0017] FIG. 6 is a fluid circuit diagram showing a specimen preparation section of the measurement unit according to the embodiment; [0018] FIG. 7 is a perspective view schematically showing a configuration of a flow cell according to the embodiment; [0019] FIG. 8 schematically shows a configuration of a flow cytometer according to the embodiment; [0020] FIG. 9 is a block diagram showing a configuration of a data processing unit according to the embodiment; [0021] FIG. 10 is a flowchart of processing performed when reticulocytes are measured according to the embodiment; [0022] FIG. 11 is a flowchart showing a sub routine of an analysis process according to the embodiment; [0023] FIGS. 12A and 12B each show a scattergram illustrating the analysis process according to the embodiment; [0024] FIGS. 13A and 13B each show a demarcation process performed on the scattergram according to the embodiment; [0025] FIGS. 14A and 14B each show demarcation on the scattergram according to the embodiment; [0026] FIGS. 15A and 15B each schematically show the manner of setting a threshold value Thr according to the embodiment; [0027] FIGS. 16A and 16B each schematically show a micrograph that shows an image of feline blood; [0028] FIGS. 17A and 17B each show an example of verification of the blood cell measuring apparatus according to the embodiment; and [0029] FIG. 18 is a flowchart showing a variation of an analysis routine according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0030] Hereinafter, an animal blood cell measuring apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the description below, from among features of the animal blood cell measuring apparatus, features relating to counting of reticulocytes are mainly described, and descriptions of features relating to measurement of white blood cells and the like are omitted. [0031] FIG. 1 is a front view showing a schematic configuration of the animal blood cell measuring apparatus according to the present embodiment. As shown in FIG. 1 , main components of a blood cell measuring apparatus 1 according to the present embodiment are a measurement unit 2 and a data processing unit 3 . The measurement unit 2 performs predetermined measurement on blood components contained in a blood sample, and transmits measurement data to the data processing unit 3 . The data processing unit 3 performs an analysis process based on the measurement data, and displays analysis results on a monitor. The blood cell measuring apparatus 1 is installed in a veterinary hospital, for example. [0032] The measurement unit 2 and the data processing unit 3 are connected via a data transmission cable 3 a so that the measurement unit 2 and the data processing unit 3 can perform data communication therebetween. Note that the connection formed between the measurement unit 2 and the data processing unit 3 is not limited to a direct connection formed by the data transmission cable 3 a . For example, the measurement unit 2 and the data processing unit 3 may be connected via a dedicated line using a telephone line, via a LAN, or via a communication network such as the Internet. [0033] FIG. 2 is a perspective external view of the measurement unit 2 . As shown in FIG. 2 , provided at the lower right of the front face of the measurement unit 2 is a blood collection tube setting part 2 a on which a blood collection tube 20 containing a blood specimen can be set. When a user presses a push button switch 2 b provided near the blood collection tube setting part 2 a , the blood collection tube setting part 2 a opens and protrudes forward. This allows the user to set the blood collection tube 20 on the blood collection tube setting part 2 a . When the user presses the button switch 2 b again after the blood collection tube 20 is set, the blood collection tube setting part 2 a recedes and closes. On the front face of the measurement unit 2 , a start button 2 c for starting sample measurement is also provided. [0034] FIG. 3 is a perspective view showing an internal structure of the measurement unit 2 . FIG. 4 is a side view of the internal structure. [0035] The blood collection tube setting part 2 a , on which the blood collection tube 20 is set, is accommodated within the measurement unit 2 in the above-described manner. Accordingly, the blood collection tube 20 is positioned at a predetermined aspirating position. Provided within the measurement unit 2 are: a pipette 21 for aspirating the blood specimen; and a specimen preparation section 4 that has, for example, chambers 22 and 23 for mixing the blood and reagents. [0036] The pipette 21 has a tubular shape extending in the vertical direction, and has a sharp-pointed tip. The pipette 21 is connected to a syringe pump that is not shown. The pipette 21 is capable of aspirating and discharging a predetermined amount of liquid through operation of the syringe pump. The pipette 21 is further connected to a moving mechanism, and accordingly, is movable in the vertical and front-rear directions. [0037] The blood collection tube 20 is sealed with a rubber cap 20 a . The sharp tip of the pipette 21 pierces through the cap, which allows the pipette 21 to aspirate, by a predetermined amount, the blood specimen contained in the blood collection tube 20 . As shown in FIG. 4 , the chambers 22 and 23 are provided behind the blood collection tube setting part 2 a . The pipette 21 having aspirated the blood specimen is moved by the moving mechanism and then discharges the blood specimen into the chambers 22 and 23 . In this manner, the blood specimen is supplied to the chambers 22 and 23 . [0038] FIG. 5 is a block diagram showing a configuration of the measurement unit 2 . FIG. 6 is a fluid circuit diagram showing a configuration of the specimen preparation section 4 . As shown in FIG. 5 , the measurement unit 2 includes the specimen preparation section 4 , an RET detector 5 , an RBC detector 6 , an HGB detector 7 , a controller 8 , and a communication section 9 . [0039] The controller 8 includes a CPU, a ROM, a RAM, and the like, and controls the operation of each component of the measurement unit 2 . The communication section 9 is, for example, an RS-232C interface, a USB interface, or an Ethernet (registered trademark) interface, and transmits/receives data to/from the data processing unit 3 . [0040] As shown in FIG. 6 , the specimen preparation section 4 is a fluid unit that includes the chambers, a plurality of solenoid valves, diaphragm pumps, and the like. The chamber 22 is used for preparing a specimen that is used for measuring red blood cells, platelets, and hemoglobin. The chamber 23 is used for preparing a specimen that is used for measuring reticulocytes. Note that, in order to simplify the description, FIG. 6 only shows a part of the configuration of the fluid circuit, the part being in the vicinity of the chamber 23 . [0041] The chamber 23 is connected to a reagent container RC 1 that contains a diluent containing a hemolytic agent and to a reagent container RC 2 that contains a stain solution, via fluid flow paths P 1 and P 2 that are tubes, for example. Along the fluid flow path P 1 connecting the chamber 23 and the reagent container RC 1 , solenoid valves SV 19 and SV 20 are provided. Also, a diaphragm pump DP 4 is provided between the solenoid valves SV 19 and SV 20 . The diaphragm pump DP 4 is connected to a positive pressure source and a negative pressure source so that the diaphragm pump DP 4 can be driven by positive pressure and negative pressure. Further, along the fluid flow path P 2 connecting the chamber 23 and the reagent container RC 2 , solenoid valves SV 40 and SV 41 are provided. A diaphragm pump DP 5 is provided between the solenoid valves SV 40 and SV 41 . [0042] The controller 8 controls these solenoid valves SV 19 , SV 20 , SV 40 , SV 41 , and the diaphragm pumps DP 4 and DP 5 in a manner described below, thereby supplying the diluent containing the hemolytic agent and the stain solution to the chamber 23 . [0043] First, the solenoid valve SV 19 , which is provided closer to the reagent container RC 1 than the diaphragm pump DP 4 , is opened, and the diaphragm pump DP 4 is driven by negative pressure while the solenoid valve SV 20 , which is provided closer to the chamber 23 than the diaphragm pump DP 4 , is kept closed. As a result, a fixed quantity of the diluent is taken from the reagent container RC 1 . Thereafter, the solenoid valve SV 19 is closed and the solenoid valve SV 20 is opened, and the diaphragm pump DP 4 is driven by positive pressure, whereby the diluent of the fixed quantity is supplied to the chamber 23 . [0044] Similarly, the solenoid valve SV 40 , which is provided closer to the reagent container RC 2 than the diaphragm pump DP 5 , is opened. Then, the diaphragm pump DP 5 is driven by negative pressure while the solenoid valve SV 41 , which is provided closer to the chamber 23 than the diaphragm pump DP 5 , is kept closed. As a result, a fixed quantity of the stain solution is taken from the reagent container RC 2 . Thereafter, the solenoid valve SV 40 is closed and the solenoid valve SV 41 is opened, and the diaphragm pump DP 5 is driven by positive pressure, whereby the stain solution of the fixed quantity is supplied to the chamber 23 . In this manner, the blood specimen and the reagents (the diluent and the stain solution) are mixed and thereby a specimen to be used for measurement of reticulocytes is prepared. [0045] The chamber 23 is connected to the RET detector 5 that is a flow cytometer, via a fluid flow path P 3 that includes a tube and a solenoid valve SV 4 . The fluid flow path P 3 has a branch, and solenoid valves SV 1 and SV 3 are serially connected to the branch path. A syringe pump SP 2 is provided between the solenoid valves SV 1 and SV 3 . A stepping motor M 2 is connected to the syringe pump SP 2 . The syringe pump SP 2 is driven through the operation of the stepping motor M 2 . [0046] The fluid flow path P 3 connecting the chamber 23 and the RET detector 5 has another branch, and a solenoid valve SV 29 and a diaphragm pump DP 6 are connected to this other branch. In the case of measuring reticulocytes by using the RET detector 5 , the diaphragm pump DP 6 is driven by negative pressure while the solenoid valves SV 4 and SV 29 are kept open, and the specimen is aspirated from the chamber 23 . In this manner, the fluid flow path P 3 is charged with the specimen. When the charging of the specimen is completed, the solenoid valves SV 4 and SV 29 are closed. Thereafter, the solenoid valve SV 3 is opened and the syringe pump SP 2 is driven, whereby the charged specimen is supplied to the RET detector 5 . [0047] As shown in FIG. 6 , the specimen preparation section 4 is provided with a sheath liquid chamber 24 . The sheath liquid chamber 24 is connected to the RET detector 5 via a fluid flow path P 4 . The fluid flow path P 4 is provided with a solenoid valve SV 31 . The sheath liquid chamber 24 is provided for storing a sheath liquid to be supplied to the RET detector 5 . The sheath liquid chamber 24 is connected to a sheath liquid container EPK containing the sheath liquid, via a fluid flow path P 5 that includes a tube and a solenoid valve SV 33 . Note that the diluent contained in the reagent container RC 1 may be used as the sheath liquid. [0048] Before the measurement of reticulocytes starts, the solenoid valve SV 33 is opened and the sheath liquid is supplied to the sheath liquid chamber 24 . In this manner, the sheath liquid is stored in the sheath liquid chamber 24 in advance. At the start of the measurement of reticulocytes, a solenoid valve SV 31 is opened in synchronization with the aforementioned supplying of the specimen to the RET detector 5 , and thereby the sheath liquid stored in the sheath liquid chamber 24 is supplied to the RET detector 5 . [0049] The RET detector 5 is an optical flow cytometer that is capable of measuring reticulocytes by flow cytometry using a semiconductor laser. The RET detector 5 includes a flow cell 51 for forming a liquid flow of the specimen. [0050] FIG. 7 is a perspective view schematically showing a configuration of the flow cell 51 . The flow cell 51 is formed from a translucent material such as quartz, glass, synthetic resin or the like, and has a tubular shape. The flow cell 51 has a flow path therein, through which the specimen and the sheath liquid flow. The flow cell 51 is provided with an orifice 51 a , at which the inner space of the flow cell 51 is narrower than the inner space of the other parts of the flow cell 51 . The flow cell 51 has a double-tube structure in the vicinity of the entrance of the orifice 51 a . The inner tube portion thereof serves as a specimen nozzle 51 b . The specimen nozzle 51 b is connected to the fluid flow path P 3 of the specimen preparation section 4 . The specimen is discharged from the specimen nozzle 51 b to the orifice 51 a. [0051] Space outside the specimen nozzle 51 b serves as a flow path 51 c through which the sheath liquid flows. The flow path 51 c is connected to the aforementioned fluid flow path P 4 . The sheath liquid supplied from the sheath liquid chamber 24 flows through the fluid flow path P 4 into the flow path 51 c , and is then led to the orifice 51 a . The sheath liquid supplied to the flow cell 51 in this manner flows so as to surround the specimen discharged from the specimen nozzle 51 b . Then, the orifice 51 a narrows down the stream of the specimen. As a result, particles contained in the specimen, such as reticulocytes and red blood cells, which are surrounded by the sheath liquid, pass through the orifice 51 a one by one. [0052] FIG. 8 shows a schematic configuration of the RET detector 5 . In the RET detector 5 , a semiconductor laser light source 52 is disposed so as to output laser light to the orifice 51 a of the flow cell 51 . An illumination lens system 53 including a plurality of lenses is provided between the semiconductor laser light source 52 and the flow cell 51 . The illumination lens system 53 focuses a parallel beam outputted from the semiconductor laser light source 52 , to form a beam spot. [0053] On an optical axis that linearly extends from the semiconductor laser light source 52 , a beam stopper 54 a is provided in an opposed position to the illumination lens system 53 , with the flow cell 51 provided therebetween. Among laser beams outputted from the semiconductor laser light source 52 , a beam that travels straight within the flow cell 51 without being scattered (hereinafter, referred to as “direct light”) is blocked by the beam stopper 54 a . Further, a photodiode 54 is provided on the optical axis so as to be located to the downstream side of the beam stopper 54 a. [0054] When the specimen flows into the flow cell 51 , scattered light signals and fluorescence signals occur due to the laser light, among which forward light signals (scattered light signals) are emitted toward the photodiode 54 . From among lights traveling along the optical axis that linearly extends from the semiconductor laser light source 52 , the direct light from the semiconductor laser light source 52 is blocked by the beam stopper 54 a . Incident on the photodiode 54 is only the scattered light that travels substantially along the optical axis direction (hereinafter, referred to as forward scattered light). [0055] The forward scattered light emitted from the flow cell 51 is photoelectrically converted by the photodiode 54 . Each electrical signal resulting from the photoelectric conversion (hereinafter, referred to as a forward scattered light signal) is amplified by an amplifier 54 b and then outputted to the controller 8 . The forward scattered light signal indicates a size of a blood cell. The forward scattered light signal is, after being processed by the controller 8 , outputted to the data processing unit 3 via the communication section 9 . [0056] A side condenser lens 55 is provided laterally to the flow cell 51 , so as to be located in a direction that is perpendicular to the optical axis that linearly extends from the semiconductor laser light source 52 to the photodiode 54 . The side condenser lens 55 condenses side light that occurs when the semiconductor laser illuminates blood cells that are passing through the flow cell 51 (i.e., light that is outputted in the direction perpendicular to the optical axis). A dichroic mirror 56 is provided to the downstream side of the side condenser lens 55 . Side light signals transmitted from the side condenser lens 55 are separated by the dichroic mirror 56 into scattered light components and fluorescence components. [0057] A photodiode 57 for receiving side scattered light is provided laterally to the dichroic mirror 56 (i.e., provided in a direction that intersects an optical axis direction connecting the side condenser lens 55 and the dichroic mirror 56 ). Further, an optical filter 58 a and an avalanche photodiode 58 are provided, on the optical axis, to the downstream side of the dichroic mirror 56 . [0058] Side scattered light components reflected by the dichroic mirror 56 are photoelectrically converted by the photodiode 57 . Each electrical signal resulting from the photoelectric conversion (hereinafter, referred to as a side scattered light signal) is amplified by an amplifier 57 a , and then outputted to the controller 8 . The side scattered light signal indicates information about the inside of a blood cell (e.g., the size of the nucleus). The side scattered light signal is outputted to the data processing unit 3 via the communication section 9 after being processed by the controller 8 . [0059] Side fluorescence components transmitted through the dichroic mirror 56 are photoelectrically converted by the avalanche photodiode 58 after being wavelength-selected by the optical filter 58 a . Each electrical signal resulting from the photoelectric conversion (a side fluorescence signal) is amplified by an amplifier 58 b , and then outputted to the controller 8 . The side fluorescence signal indicates information about the degree of staining of a blood cell. The side fluorescence signal is, after being processed by the controller 8 , outputted to the data processing unit 3 via the communication section 9 . [0060] The RBC detector 6 is capable of measuring a red blood cell count and a platelet count by the sheath flow DC detection method. The RBC detector 6 has an electrical resistance detector. The aforementioned specimen is supplied from the chamber 22 to this detector. In the case of performing measurement on red blood cells and platelets, the specimen is prepared in the chamber 22 by mixing the blood with a diluent. The specimen is supplied from the specimen preparation section 4 to the detector, together with the sheath liquid. Within the detector, a liquid flow in which the specimen is surrounded by the sheath liquid is formed in the same manner as described above. [0061] Along a flow path within the detector, an aperture having an electrode is provided. When blood cells contained in the specimen pass through the aperture one by one, a DC resistance at the aperture is detected, and an electrical signal corresponding to the DC resistance is outputted to the controller 8 . The DC resistance increases when a blood cell passes through the aperture. Accordingly, the electrical signal is information indicating the passage of the blood cell through the aperture. The electrical signal is processed by the controller 8 , and then transmitted to the data processing unit 3 via the communication section 9 . The data processing unit 3 analyzes the received data to count red blood cells and platelets. [0062] The HGB detector 7 is capable of measuring hemoglobin content by the SLS-hemoglobin method. The HGB detector 7 is provided with a cell for containing the diluted specimen. The specimen is supplied from the chamber 22 to the cell. In the case of measuring hemoglobin, the specimen is prepared in the chamber 22 by mixing the blood with a diluent and a hemolytic agent. The hemolytic agent has a property of converting hemoglobin in the blood to SLS-hemoglobin. A light-emitting diode and a photodiode are arranged so as to be opposed to each other with the cell located therebetween. Light from the light emitting diode is received by the photodiode. [0063] The light-emitting diode emits light of a wavelength having a high rate of absorption by SLS-hemoglobin. The cell is formed from a plastic material having high translucency. As a result, the light emitted from the light-emitting diode is absorbed almost solely by the diluted specimen, and the transmitted light is received by the photodiode. The photodiode outputs an electrical signal corresponding to the amount of the received light (i.e., corresponding to an absorbance) to the controller 8 . The absorbance and an absorbance obtained in advance by measuring only the diluent are subjected to signal processing by the controller 8 , and then transmitted to the data processing unit 3 via the communication section 9 . The data processing unit 3 compares the absorbances in the above two cases to calculate a hemoglobin value. [0064] FIG. 9 is a block diagram showing a configuration of the data processing unit 3 . The data processing unit 3 is structured as a computer system that includes: a CPU 101 ; a ROM 102 ; a RAM 103 ; a hard disk drive (HD drive) 104 ; a communication interface 105 ; an input interface 106 including a keyboard, a mouse, and the like; and an output interface 107 including a monitor, a speaker, and the like. [0065] For example, the communication interface 105 is an RS-232C interface, a USB interface, or an Ethernet (registered trademark) interface, and is capable of transmitting/receiving data to/from the measurement unit 2 . Installed in a hard disk within the HD drive 104 are an operating system and an application program that is used for performing an analysis process on measurement data received from the measurement unit 2 . [0066] Through execution of the application program by the CPU 101 , the analysis process is performed on the measurement data received from the measurement unit 2 . As a result, a red blood cell count (RBC), hemoglobin content (HGB), hematocrit value (HCT), mean red blood cell volume (MCV), mean red blood cell hemoglobin (MCH), mean red blood cell hemoglobin concentration (MCHC), and a platelet count (PLT) are calculated. Further, a scattergram is created based on the forward scattered light signals and the side fluorescence signals, whereby the number of reticulocytes (RET) is counted. [0067] FIG. 10 shows a flow of processing that is performed by the blood cell measuring apparatus according to the present embodiment when the blood cell measuring apparatus performs reticulocyte measurement. Note that the processing flow at the data processing unit 3 as shown in FIG. 10 is performed through execution, by the CPU 101 of the data processing unit 3 , of the application program stored in the HD drive 104 . [0068] When a reticulocyte measurement mode is started, a reception screen for receiving the selection of an animal species is displayed on the monitor of the data processing unit 3 (S 101 ). The reception screen includes icons indicating animal species options (feline, canine, etc). [0069] When a user selects a desired animal species from among the displayed animal species by using a mouse (S 101 : YES), a signal for activating the start button 2 c is transmitted to the measurement unit 2 (S 102 ). Thereafter, the CPU 101 waits for data transmission from the measurement unit 2 (S 103 ). [0070] When the start button 2 c is pressed (S 201 : YES), the measurement unit 2 determines whether or not the start button 2 c is active (step S 202 ). If the start button 2 c is active (step S 202 : YES), the specimen is prepared in the chamber 23 as described above. The measurement unit 2 performs measurement at the RET detector 5 by using the prepared specimen, thereby obtaining the aforementioned forward scattered light signals and the side fluorescence signals (S 203 ). Data that results from processing the obtained forward scattered light signals and the side fluorescence signals are transmitted to the data processing unit 3 (S 204 ). [0071] Upon receiving these data of the forward scattered light signals and the side fluorescence signals (S 103 : YES), the CPU 101 analyzes the data in a manner corresponding to the animal species selected at step S 101 , thereby obtaining the number of reticulocytes contained in the specimen (S 104 ). Information about the obtained reticulocyte count is displayed on the monitor (S 105 ). After the measurement and display of the reticulocytes have been performed for the animal species desired by the user, the processing returns, if the system is not shut down (S 106 : N 0 , S 205 : NO), to step S 101 and step S 201 at which the next measurement instruction from the user is awaited. [0072] FIG. 11 shows a process routine of the analysis process at step S 104 . FIGS. 12A to 14B show the manner of performing demarcation on a scattergram in the process routine. FIGS. 12A to 14A show an example of a scattergram in the case where feline blood is measured. FIG. 14B shows an example of a scattergram in the case where canine blood is measured. These scattergrams may be either two-dimensional scattergrams or three-dimensional scattergrams. For example, a two-dimensional scattergram is a distribution chart in which plot data, which indicate blood cells based on magnitudes of a parameter that is set as the vertical axis and based on magnitudes of a parameter that is set as the horizontal axis, are assigned to predetermined coordinates. Each set of coordinates is associated with values of plot data assigned thereto. [0073] As described above, the analysis process at step S 104 is performed in a manner corresponding to the animal species selected at step S 101 . When the animal species has been selected at step S 101 , demarcation conditions corresponding to the selected animal species (parameter values used for the demarcation) are set. In accordance with the demarcation conditions, demarcation is performed on a scattergram and reticulocytes are counted. [0074] Upon receiving the data of the forward scattered light signals and the side fluorescence signals from the measurement unit 2 , the CPU 101 first generates, at step S 301 , a scattergram whose vertical axis and horizontal axis represent the intensity of the forward scattered light and the intensity of the side fluorescence, respectively (see FIG. 12A ). Next, at step S 302 , the CPU 101 demarcates a coordinate area of platelets (PLT) on the scattergram (see FIG. 12B ), and also, demarcates a coordinate area of white blood cells (WBC) (see FIG. 13A ). Here, demarcation of the coordinate area of white blood cells (WBC) is performed as described below. [0075] First, an axis O that passes through the centroid of a distribution of red blood cells (RBC) is set on the scattergram (see FIG. 13A ). Here, the centroid of the distribution is set based on plot data present within a fixed area R that is set in advance around a coordinate area of the red blood cells (RBC). To be specific, a histogram in the vertical axis direction is obtained for the plot data present within the fixed area R. Then, the mean position of the histogram in the vertical axis direction is calculated. The mean position is set as the centroid of the distribution of red blood cells (RBC), and the axis O is set so as to extend through the centroid of the distribution and so as to be in parallel with the horizontal axis. A straight line with a slope γ is drawn from a point that is shifted in the positive vertical axis direction by β from an intersection point between the axis O set as above and a boundary indicating the maximum value of the side fluorescence intensity. An area, surrounded with the drawn straight line and a straight line that defines a fixed width W together with the boundary, is set as the coordinate area of white blood cells (WBC). [0076] After the coordinate areas of platelets (PLT) and white blood cells (WBC) have been demarcated, the CPU 101 calculates, at step S 304 , a frequency distribution 150 of plot data with respect to the side fluorescence intensity, based on the scattergram from which these coordinate areas have been removed (see FIG. 13B ). [0077] Note that, in the example shown in FIG. 13B , plot data is projected onto an axis that is a result of rotating the horizontal axis of the scattergram by θ in the clockwise direction. In this manner, the frequency distribution 150 is calculated, with the rotated axis representing the side fluorescence intensity. This is because, as is understood from FIG. 13B , an area where a cluster of plot data of red blood cells (RBC) is present is an ellipsoidal area that is in a slightly rotated orientation in the clockwise direction. The rotation angle of the area where the cluster of plot data is present is variable depending on the reagents to be used in preparing the specimen. Depending on the reagents to be used, the area where the cluster of plot data of red blood cells (RBC) is present is not in such a rotated orientation but in the shape of an ellipse that is elongated in the vertical axis direction. Accordingly, when the frequency distribution is calculated, a rotation angle θ by which the axis representing the side fluorescence intensity is rotated is adjusted in accordance with the reagents to be used. Further, when the area where the cluster of plot data of red blood cells (RBC) is present is not in such a rotated orientation as above, the frequency distribution of plot data is calculated with respect to the horizontal axis of the scattergram. [0078] When the frequency distribution has been calculated in this manner, the CPU 101 obtains at step S 305 , fluorescence intensity X that corresponds to a peak of the frequency distribution, and further calculates a variance σ of the frequency distribution. Then, at step S 306 , the CPU 101 determines whether or not the animal species set by the user at step S 101 of FIG. 10 is a first animal species (e.g., a “feline”). In the case of the first animal species (step S 306 : YES), the CPU 101 performs, at step S 307 , calculation based on the fluorescence intensity X, the variance σ, and a coefficient α corresponding to the first animal species (a “feline” in the example of FIGS. 12A to 14A ), thereby calculating a threshold value Thr that indicates a border of aggregate reticulocytes (RET). The calculation is performed using the equation shown below. [0000] Thr= X+α×σ   (1) [0079] After the threshold value Thr has been calculated in the above manner, the CPU 101 demarcates, at step S 309 , a coordinate area of aggregate reticulocytes (RET) and a coordinate area of red blood cells (RBC) (the red blood cells including punctate reticulocytes (RET)), with a straight line L 1 that is inclined by an angle θ with respect to the vertical axis of the scattergram and that passes through the threshold value Thr, and with a straight line L 2 that extends downward, in parallel with the vertical axis, from an intersection point of the straight line L 1 and the axis O (see FIG. 13B ). In this manner, the coordinate area of aggregate reticulocytes (RET) is specified (see FIG. 14A ). Thereafter, at step S 311 , the CPU 101 counts the number of plot data (the number of blood cells) contained in the coordinate area of aggregate reticulocytes (RET). [0080] On the other hand, when the animal species set by the user at step S 101 is not the first animal species (step S 306 : NO), the CPU 101 calculates, at step S 308 based on the above equation (1), a threshold value Thr by using a coefficient α that corresponds to an animal species different from the first animal species. Then, the CPU 101 demarcates, at step S 310 , a coordinate area of reticulocytes (RET) (including both punctate reticulocytes and aggregate reticulocytes) and a coordinate area of red blood cells (RBC), with a straight line L 1 that is inclined by the angle θ with respect to the vertical axis of the scattergram and that passes through the threshold value Thr, and with a straight line L 2 that extends downward, in parallel with the vertical axis, from an intersection point of the straight line L 1 and an axis O. In this manner, the coordinate area of reticulocytes (RET) is specified (see FIG. 14B ). Subsequently, the CPU 101 counts, at step S 311 , the number of plot data (the number of blood cells) contained in the coordinate area of reticulocytes (RET). [0081] In the case of an animal species different from the first animal species (e.g., a “canine”), the coefficient α in the above equation (1) is set to be ½ of the coefficient α in the case of a feline. The rotation angle θ, shift amount β, slope γ, and the fixed width W are the same for both the case of a feline and the case of a canine. As is understood from the comparison between FIG. 14A and FIG. 14B , the border between the coordinate area of red blood cells (RBC) and the coordinate area of reticulocytes (RET) in the case of a canine is, as compared to the case of a feline, shifted to the left in the scattergram. Based on such a difference between the borders, the coordinate area of aggregate reticulocytes is demarcated in the case of a feline, and the coordinate area containing all the reticulocytes (regardless of the difference between punctate reticulocytes and aggregate reticulocytes) is demarcated in the case of a canine. [0082] As described above, the coefficient α of the above equation (1) used at step S 307 and step S 308 is changed as necessary in accordance with the selected animal species. FIGS. 15A and 15B each schematically show, in the case where the plot data frequency distribution calculated at step S 304 of FIG. 11 with respect to the side fluorescence intensity is divided based on blood cell types, the distribution of each type of blood cells. FIG. 15A is a distribution chart for feline blood, and FIG. 15B is a distribution chart for canine blood. [0083] As shown in FIG. 15A , in the case of feline blood, a distribution of red blood cells (RBC), which is a normal distribution, is followed by a distribution of punctate reticulocytes (RET), which is followed by a distribution of aggregate reticulocytes (RET). Counting aggregate reticulocytes is considered to be useful when diagnosing animal species with anemia or the like, whose reticulocytes consist of a plurality of types of reticulocytes in the above manner. Therefore, in the case of feline blood, it is necessary to demarcate the coordinate area of reticulocytes (RET), with the threshold value Thr being set at the border position between the punctate reticulocytes and the aggregate reticulocytes. [0084] On the other hand, in the case of canine blood, as shown in FIG. 15B , it is not necessary to distinguish between punctate reticulocytes and aggregate reticulocytes contained in the reticulocytes, but necessary to count the total number of reticulocytes (RET) that are distributed following the normally distributed red blood cells (RBC). Accordingly, in the case of canine blood, it is necessary to demarcate the coordinate area of reticulocytes (RET), with the threshold value Thr being set at the border position between the red blood cells (RBC) and the reticulocytes (RET). [0085] As described above, the distribution of reticulocytes to be measured is different between the case of a canine and the case of a feline. For this reason, the coefficient α in the above equation (1) is required to be changed between the case of feline blood and the case of canine blood. It is at least necessary to set the coefficient α in the case of feline blood to be greater by a predetermined magnitude than that in the case of canine blood. To be specific, in the case of feline blood, the coefficient α is adjusted to be approximately the double of that in the case of canine blood. [0086] After the blood cells in the RET coordinate area have been counted, the CPU 101 counts, at step S 312 , the number of plot data contained in the coordinate area of red blood cells (RBC), which has been demarcated at step S 309 or step S 310 . Further, the CPU 101 calculates, at step S 313 , a proportion RET % that indicates a proportion of the number of reticulocytes to the counted number of red blood cells (RBC). [0087] In parallel to the above process, the CPU 101 obtains, from the measurement unit 2 at step S 314 , information about the number of red blood cells (RBC), which has been obtained by the RBC detector 6 for the same blood. Further, at step S 315 , the CPU 101 obtains a count RET# that indicates the number of reticulocytes, by multiplying the obtained number of red blood cells (RBC) by the proportion RET %. [0088] Here, the reticulocyte count RET# is obtained here by multiplying, by the proportion RET %, the number of red blood cells detected by the RBC detector 6 . However, as an alternative, the number of reticulocytes (RET) obtained at step S 311 can be used as the reticulocyte count RET#. [0089] The reticulocyte proportion RET % and the reticulocyte count RET# measured in this manner are displayed on the monitor at step S 105 of FIG. 10 . [0090] Described next are results that were obtained when measurement of aggregate reticulocytes (of a feline) was performed with the blood cell measuring apparatus according to the present embodiment (prototype). [0091] FIGS. 16A and 16B are schematic diagrams each showing a micrograph that shows feline blood. In each diagram, a blood cell that contains therein two or more granules (RNA) is a reticulocyte (RET). Among reticulocytes, those with granules aggregated therein are aggregate reticulocytes, and those with granules scattered therein are punctate reticulocytes. [0092] In this measurement, measurement results of aggregate reticulocytes which were obtained when feline blood was measured by the blood cell measuring apparatus according to the present embodiment (prototype) were compared to measurement results of aggregate reticulocytes which were obtained when blood cells in the feline blood were visually measured with a microscope, whereby measurement accuracy of the blood cell measuring apparatus according to the present embodiment was verified. Each measurement was performed on 47 samples. Mean values of results of measurement performed by multiple persons are shown as the results of the visual measurement. The measurement by the blood cell measuring apparatus (prototype) was performed in accordance with the processing described above with reference to FIGS. 11 to 14B . Parameter values used for demarcation on a scattergram were set to those used for measurement of feline blood. The coefficient α in the above equation (1) was set to α=10 (double the coefficient α in the case of human or canines). [0093] FIGS. 17A and 17B show the measurement results. In FIGS. 17A and 17B , the vertical axis represents values obtained by the prototype apparatus and the horizontal axis represents values obtained by the visual measurement. Each single point plotted on these diagrams represents, for the same sample, both a measurement result obtained by the prototype apparatus and a measurement result obtained by the visual measurement. In each diagram, a straight line that approximates all the plotted points therein is calculated, whereby a correlation between the measurement results of the prototype apparatus and the results of the visual measurement is obtained. [0094] FIG. 17A shows, as measurement results, points each representing a proportion RET % that indicates a proportion of aggregate reticulocytes to the number of red blood cells. FIG. 17B shows, as measurement results, points each representing a count RET# that indicates the number of aggregate reticulocytes. Note that the count RET# was, similarly to the above-described manner, calculated by multiplying the number of red blood cells (a measurement result obtained by the RBC detector 6 of FIG. 5 ), which had been obtained based on a change in the electrical resistance value, by the proportion RET % calculated as shown in FIG. 17A . [0095] A correlation r between the measurement results of the prototype apparatus and the results of the visual measurement, which is shown in FIG. 17A , and a correlation r between the measurement results of the prototype apparatus and the results of the visual measurement, which is shown in FIG. 17B , are r=0.924 and r=0.896, respectively. Thus, there is a substantially high correlation between the measurement results obtained by the prototype apparatus and the results obtained by the visual measurement. From these measurement results, measurement accuracy of the blood cell measuring apparatus according to the present embodiment (prototype) was verified to be sufficiently high when used in measurement of feline blood. [0096] As described above, according to the present embodiment, the number of aggregate reticulocytes can be counted accurately. Since the number of aggregate reticulocytes can be counted without depending on visual measurement, a burden on veterinarians and laboratory technicians can be reduced substantially. [0097] Further, in the present embodiment, an animal species to be measured can be selected as necessary. Therefore, not only the number of aggregate reticulocytes of such animal species as felines, but also the total number of reticulocytes of other animal species such as canines, can be measured. To be specific, when a feline is selected as an animal species to be measured, information about the number of aggregate reticulocytes (RET %, RET#) is outputted, and when a canine is selected as an animal species to be measured, information about the total number of reticulocytes (RET %, RET#) is outputted. Accordingly, veterinarians or laboratory technicians are only required to select an animal species to be measured, in order to obtain information about the number of reticulocytes, which is useful for making a diagnosis on the animal species. This substantially reduces their burden in making the diagnosis. [0098] Although the above embodiment takes felines and canines as animal species to be measured, measurement can be performed on other animal species, of course. In such a case, if there exists, other than felines, animal species whose reticulocytes may contain aggregate reticulocytes, the coefficient α in the equation (1) is adjusted for the animal species, and the aggregate reticulocytes are measured, accordingly. Animal species whose reticulocytes may contain aggregate reticulocytes are, for example, rabbits, ferrets, etc. [0099] In the above embodiment, the number of aggregate reticulocytes is measured and displayed in the case of the first animal species (a feline). Here, the number of punctate reticulocytes may be additionally measured and displayed. Alternatively, the total number of reticulocytes may be measured and displayed. Further, in the case of the first animal species (a feline), the user may select as necessary whether to measure and display only the number of aggregate reticulocytes, or to measure and display the number of punctate reticulocytes in addition to the number of aggregate reticulocytes, or to measure and display the total number of reticulocytes in addition to the number of aggregate reticulocytes. [0100] Still further, the above embodiment measures aggregate reticulocytes when the first animal species is selected, and measures all the reticulocytes when the second animal species is selected. However, the present invention is not limited thereto. For example, when the first animal species is selected, punctate reticulocytes may be measured, and when the second animal species is selected, all the reticulocytes may be measured. Alternatively, when the first animal species is selected, aggregate reticulocytes may be measured, and when the second animal species is selected, punctate reticulocytes may be measured. Further alternatively, when the first animal species is selected, punctate reticulocytes may be measured, and when the second animal species is selected, aggregate reticulocytes may be measured. [0101] FIG. 18 shows a flow of processing that is performed when the number of punctate reticulocytes and the total number of reticulocytes are counted and displayed in addition to the number of aggregate reticulocytes, for the first animal species (e.g. a feline). In this processing flow, similarly to the above embodiment, a scattergram is created (S 401 ), and the coefficient α of the above equation (1) is set to a coefficient α 1 that is used for measuring aggregate reticulocytes (S 402 ). Then, similarly to the above embodiment, a coordinate area of aggregate reticulocytes is demarcated using the coefficient α 1 (S 403 ), and a count N 1 indicating the number of aggregate reticulocytes is measured (S 404 ). [0102] Here, when the user has not selected a multiple-result display (S 405 : NO), the number of reticulocytes to be displayed is, similarly to the above embodiment, regarded as the count N 1 which has been measured at step S 404 (S 412 ). Then, a display output is performed based on the count N 1 (S 413 ). [0103] On the other hand, when the user has selected a multiple-result display (C 405 : YES), the coefficient α of the above equation (1) is set to a coefficient α 2 that is used for counting the total number of reticulocytes (including all the types of reticulocytes (e.g., both punctate and aggregate reticulocytes)) (S 406 ). Then, the coefficient α 2 is used, similarly to the above embodiment, to demarcate a coordinate area of reticulocytes (including all the types of reticulocytes (e.g., both punctate and aggregate reticulocytes)) (S 407 ), and a count N 2 indicating the total number of reticulocytes is measured (S 408 ). Further, calculation N 2 −N 1 is performed, whereby a count N 3 indicating the number of punctate reticulocytes is calculated. [0104] The counts N 1 , N 2 , and N 3 obtained in the above manner are set as an aggregate reticulocyte count, a total reticulocyte count, and a punctate reticulocyte count, respectively (S 410 ). Then, similarly to the above embodiment, a display output (RET %, RET#) based on each blood cell count is performed (S 411 ). Note that when the user has selected only a display of the total number of reticulocytes in addition to a display of measurement results of aggregate reticulocytes, a display is performed for the number of aggregate reticulocytes and the total number of reticulocytes. In this case, step S 409 of FIG. 18 is skipped. Further, when the user has selected only a display of measurement results of aggregate and punctate reticulocytes, a display is performed for the aggregate and punctate reticulocytes. [0105] The embodiment of the present invention has been described as above. However, the present invention is not limited by the above embodiment in any way. Other than the foregoing description, numerous modifications of the embodiment of the present invention may be devised. [0106] For example, the above embodiment generates a scattergram based on the intensity of the forward scattered light and the intensity of the side fluorescence, for the measurement of aggregate reticulocytes. Alternatively, aggregate reticulocytes may be measured based on the intensity of the side scattered light and the intensity of the side fluorescence, for example. Further alternatively, aggregate reticulocytes may be measured based on a plurality of types of fluorescence that are generated through illumination of laser light of a specific wavelength. [0107] Further, FIGS. 12A to 14B referred to in the above embodiment indicate a feline as an example of the first animal species whose reticulocytes contain aggregate reticulocytes, and indicate a canine as an example of the second animal species whose reticulocytes do not contain aggregate reticulocytes. However, the first and second animal species may include different animal species other than felines and canines. The present invention can be applied, as necessary, to a blood cell measuring apparatus that performs measurement on animal species different from felines and canines. [0108] Although the above embodiment displays both RET % and RET#, only either one of these may be displayed, alternatively. Further, other than the above information, different information based on the number of aggregate reticulocytes may be displayed. [0109] Note that, in the measurement example of the above embodiment, the coefficient α of the above equation (1) in the case of measuring feline blood is set to be the double of that in the case of animal species whose reticulocytes do not contain aggregate reticulocytes (human or canines). However, the coefficient α here may not necessarily be the double of that in the case of human or canines, so long as the coefficient α is set to an appropriate value that is close to the double of the coefficient α used in the case of human or canines. The term “double” recited in claim 12 covers a range that is slightly greater and slightly less than the value that is double the coefficient α used in the case of human or canines. [0110] Other than the above-described embodiment, various modifications can be devised as necessary without departing from the scope of the technical idea described in the claims.

An animal blood cell measuring apparatus comprising: a specimen preparation section for preparing a measurement specimen from blood of an animal; a characteristic information obtaining section for obtaining characteristic information indicating a characteristic of the measurement specimen, from the measurement specimen prepared by the specimen preparation section; and a controller configured for performing operations comprising: (a) classifying aggregate reticulocytes contained in the blood from other blood cells, based on the characteristic information obtained by the characteristic information obtaining section; and (b) outputting information regarding a number of the classified aggregate reticulocytes.

FIELD OF THE INVENTION [0001] The present invention relates to methods for producing metal-supported thin layer skeletal catalyst structures, to methods for producing catalyst support structures without separately applying an intermediate washcoat layer, and to novel catalyst compositions produced by these methods. Catalyst precursors may be interdiffused with the underlying metal support then activated to create catalytically active skeletal alloy surfaces. The resulting metal-anchored skeletal layers provide increased conversion per geometric area compared to conversions from other types of supported alloy catalysts of similar bulk compositions, and provide resistance to activity loss when used under severe on-stream conditions. Particular compositions of the metal-supported skeletal catalyst alloy structures can be used for conventional steam methane reforming to produce syngas from natural gas and steam, for hydrodeoxygenation of pyrolysis bio-oils, and for other metal-catalyzed reactions inter alia. The interdiffused alloy surfaces optionally may be formed into bulk monolithic structures (before or after activation) and further treated in an oxidation step to generate adherent oxide layers that provide intrinsic support surfaces for secondarily applied catalytic agents such as dispersed precious or platinum group metals. Metal substrate form factors such as fibers can be treated by the methods described herein to generate adherent thin-layer skeletal catalysts and/or catalyst supports, which, in turn, can be fabricated into structures of high geometric-surface-area-to-volume ratios. BACKGROUND [0002] Intensified processing methodologies are used increasingly in place of traditional chemical processing routes when small production volumes are warranted or when portability of process equipment is desired. For example, large scale hydroprocessing of biofuels derived from local sources is impractical for isolated military units in remote locations. Instead, portable conversion units and/or units with small footprints are needed. However large scale processing reactors are not easily downscaled for such uses. Thus, the need exists for competent catalysts and corresponding reactor configurations that are suitable for on-site process chemistry in small, modular units. [0003] Simply operating established heterogeneous catalysts in compact reactor configurations at higher space velocities and at more severe temperatures than used in traditional processing will not necessarily increase productivity as needed. Under such modified conditions, mass and heat transfer limitations attenuate maximum catalyst activity, especially when such processes are conducted in traditional reactor designs. Consequently, intrinsically fast catalytic cycles alone afford no additional productivity benefits without addressing the mass and heat transfer limitations. [0004] A variety of different shapes and styles of heterogeneous catalysts are currently available that seek to augment the ratio of geometric surface area to occupied reactor volume as a means of mitigating mass and heat transfer limitations. Preformed metallic scaffolding structures are preferred over ceramic scaffolding structures when very thin walls or low pressure drop is needed in densely packed channel structures such as those desirable for intensified processing. In particular, microchannel constructs, such as thin-walled metallic honeycombs, covered with a minimally thick catalytic layer, have been sought to decrease resistance between process fluids and channel walls thereby promoting rapid convective heat and mass transfer as well as conductive heat transfer. [0005] The ratio of surface atoms exposed to process fluids to total atoms of a catalytically active metal cluster is termed “dispersion” for the purposes of this discussion. Catalyst support surfaces that enable high dispersion of applied catalytic agents are sought in the art. To reduce required content of costly catalytic components and to achieve sufficiently high dispersion to promote high catalytic activity per structural unit, base metal or precious or platinum group metal heterogeneous catalysts usually are applied to catalyst support materials, often composed of high surface area oxide powders. Typically, structured catalyst supports are produced by applying an intermediate washcoat layer of inert metal oxide or aqueous hydroxide slurries directly onto metal foils that have been preformed into a desired scaffolding structure. A second application of precursors transformable to reduced metal clusters, e.g. alcoholic or aqueous solutions of metal salts, is usually applied afterward. Alternatively, the metal salts can be admixed with the oxide or hydroxide aqueous slurries and applied in one step to the metal substrate. Catalytically active metals or active compounds are thereby distributed within the washcoat layer, rather than in exclusive direct contact with bare metal substrate. The active material therefore sits on the surface of the intermediate washcoat layer and is insulated from the underlying metallic substrate. As such, the washcoating is susceptible to damage, such as delamination, from aggressive physical manipulation and/or intensified process conditions because the coating is only weakly adhered to the underlying metal scaffolding structure. These catalyst structures usually are coated after physical forming of the scaffold to minimize damage to the cured catalyst coatings that could result if mechanical processing were done after application of the washcoat. [0006] The application of slurries to preformed substrates also can result in the coating having a nonuniform distribution. Preformed substrates are normally dip-coated or spray-coated with the washcoat slurry, and excess slurry is removed using an air knife. Excess slurry is difficult to remove from small crevices and corners, particularly in catalyst structures containing microchannels, and can result in varying thicknesses of the washcoat throughout the catalyst structure, which leads to a catalyst layer of varying thickness on the substrate. [0007] When such a supported catalyst is used to accelerate an exothermic reaction, e.g. catalytic oxidation of entrapped soot particles or of gaseous hydrocarbons, the varying thickness of the catalyst could result in hot spots forming in the catalyst layer, which in turn can cause melting of the substrate or sintering of the active phase, thereby prematurely reducing dispersion and corresponding activity. An alternative to the use of high surface area supported base metals as catalysts is the possibility for use of bulk skeletal metal aggregates, such as Raney metals, to prepare highly active catalysts. These skeletal metal particles typically are used in slurry phase processing or, less commonly, in packed beds. The latter usually suffer from pressure drop or particulation problems in practical use. Small channel monolith structures containing bound bulk skeletal metal catalysts, which in principle could generate a diminished pressure drop compared to packed beds under high space velocity conditions, would be difficult and costly to fabricate. Furthermore, under severe process conditions, such as encountered in steam methane reforming for example, bulk skeletal metal aggregates would rapidly deactivate due to surface sintering or easily delaminate from their underlying scaffolding, if used. SUMMARY OF THE INVENTION [0008] Accordingly, the present invention addresses problems and expands the applications in the prior art and, in a first manifestation, provides a method of producing an intrinsically bound thin-layer skeletal catalyst-coated metal foil or fiber with relatively uniform coating thickness capable of physical manipulation into a highly active catalytic monolithic structure, without requiring separate application of an intermediate washcoat or additional catalytic agents. [0009] In particular, a first aspect of the present invention is a method for making a catalyst, comprising the following steps: [0010] (a) preparing a slurry comprising one or more metal (including prealloyed) powders including aluminum; [0011] (b) coating a flat metal substrate or a flattened mat of metal fiber or a flattened woven metal fiber assembly with said slurry; [0012] (c) subjecting the coated metal substrate or coated metal fiber mat or coated woven metal fiber assembly to heat under an inert or reducing atmosphere whereby at least one of the one or more metal powders melts and interdiffuses into the surface of the flat metal substrate or metal fiber mat or woven metal fiber assembly; [0013] (d) leaching the coated metal substrate or coated metal fiber mat or coated woven metal fiber assembly obtained in step (c) in a caustic solution; [0014] (e) bathing the coated metal substrate, coated metal fiber mat or coated woven metal fiber assembly obtained in step (d) in a chelating acid solution; [0015] (f) passivating the coated metal substrate, coated metal fiber mat or coated woven metal fiber assembly obtained in step (e); and [0016] (g) optionally abrading the surface of the coated metal substrate, coated metal fiber mat or coated woven metal fiber assembly obtained in step (f). [0017] The coated metal substrate or coated metal fiber mat or coated woven metal fiber assembly obtained at the end of step (c) is physically manipulated into a desired form for the final catalyst either: after step (c) and before the leaching step; or after the passivating step. [0018] In step (c) of the above-described process, the coated metal substrate, coated metal fiber mat or coated woven metal fiber assembly is heated to a temperature in the range of about 600-1100° C., preferably from about 650-910° C., for a period of time of from about 0.2 to 4 minutes, preferably from about 0.3 to 1 minute. The specific processing conditions are varied depending on the compositions of the metal substrate or metal fiber mat or woven metal fiber assembly used, its thickness, and on the alloy to be formed on the surface. The layered structure of the finished catalyst consists essentially of an upper layer of skeletal metals or alloys that has been optionally partly abraded, an interdiffusion layer that has been optionally partly exposed, and a residual substrate core (i.e., where the metal substrate core is usually the original metal of the metal substrate or the original metal that made up the metal fibers in the metal fiber mat or woven metal fiber assembly). [0019] If coiled stock is desired, steps (b) through (g) optionally can be integrated into a semi-continuous web process in which a continuously moving web of substrate material (i.e., here, the substrate material can be a flat metal foil or a flattened metal fiber mat or a flattened woven metal fiber assembly) passes from one unit operation step to the next, or with optional intermediate recoiling, until all steps are completed. If honeycomb or similar structured scaffolding form factors are desired, forming and/or fastening steps preferably can be introduced after step (c) or after step (g), with subsequent processing conducted on individual parts rather than in a web process. [0020] A second aspect of the present invention is a method for making a catalyst support structure wherein an intrinsic oxidic support layer is deliberately produced. The method comprises the following steps: [0021] (a) preparing a slurry comprising one or more metal (including prealloyed) powders including aluminum; [0022] (b) coating a flat metal substrate or a flattened metal fiber mat or a flattened woven metal fiber assembly with said slurry; [0023] (c) subjecting the coated metal substrate or coated metal fiber mat or coated woven metal fiber assembly to heat under a reducing atmosphere whereby at least one of the one or more metal powders melts and interdiffuses into the surface of the metal substrate or metal fiber mat or woven metal fiber assembly; [0024] (d) optionally leaching the coated metal substrate or coated metal fiber mat or coated woven metal fiber assembly obtained in step (c) in a caustic solution; [0025] (e) subjecting the coated and heat treated metal substrate, metal fiber mat or woven metal fiber assembly obtained in step (c) or (d), if practiced, to heat in an oxygen containing atmosphere for an additional period of time. [0026] Subjecting the coated and heat treated metal substrate, metal fiber mat or woven metal fiber assembly to heat for a second period of time in an oxygen containing atmosphere (i.e., step (e) above) can produce an alumina or mixed metal oxide intrinsic catalyst support layer that is more strongly adhered to the coated metal substrate, coated metal fiber mat or coated woven metal fiber assembly and has a more uniform thickness distribution than a washcoat layer that is obtained from a traditional spray or dip coating process using a slurry mainly composed of metal oxides, applied to fully formed monolithic structural units. Catalytic species, such as precious or platinum group metals, can be dispersed on or into the intrinsic oxidic support layer using known methods. The temperature used in step (e) is from about 400 to 950° C., preferably from about 640 to 850° C. The amount of time that the coated metal substrate, coated metal fiber mat or coated woven metal fiber assembly is held at those temperatures is from about 10 to 600 minutes, preferably from about 45 to 180 minutes. [0027] In step (c) of the above-described process, the coated metal substrate, coated metal fiber mat or coated woven metal fiber assembly is heated to a temperature in the range of about 640-1100° C., preferably from about 650-900° C., for a period of time from about 0.2 to 4 minutes, preferably from about 0.3 to 1 minute. [0028] We contemplate that steps (b) through (e) optionally can be integrated into a semi-continuous web process in which a continuously moving web of substrate material (i.e., metal foil or flattened metal fiber mat or flattened woven metal fiber assembly) passes from one unit operation step to the next, or with optional intermediate recoiling, until all steps are completed. If honeycomb or similar structured scaffolding form factors are desired, forming and/or fastening steps can be introduced most advantageously after step (c), with subsequent processing conducted on individual parts rather than in a web process. [0029] Yet another aspect of the present invention involves particular macroporous multimetallic alloy or mixed metal formulations (i.e., on the surface of a metal substrate) made during the disclosed processes for making thin layer skeletal metal structured catalysts. The alloy or mixed metal formulations are particularly useful for conventional steam methane reformation to produce syngas from natural gas and steam, and for hydrodeoxygenation of pyrolysis bio-oils, and yet inherently resistant to sintering. Other uses for the catalysts of the present invention include: (a) Fischer-Tropsch synthesis reactions (particularly Fe—Co—Zr—Al catalysts); (b) hydrogenations of fatty acids (particularly over Ni—Zr—B—Al or Ni—Cr—B—Al catalysts); and (c) partial oxidations of aromatics (particularly Au—Ni—Zr—Al catalysts). BRIEF DESCRIPTION OF THE DRAWINGS [0030] FIG. 1 is a schematic of two embodiments of the present process to make a metal-supported catalyst structure. [0031] FIGS. 2A , 2 B and 2 C are scanning electron microscope images showing a comparison of the surfaces of fresh (passivated) catalyst ( 2 A), steamed (i.e., at 900° C. for 9 hours) catalyst ( 2 B), and used catalyst that had been on stream for several hundred hours ( 2 C). [0032] FIG. 3 is a graph showing the oxygen depletion in a light-off test of n-heptane over a platinum group metal catalyst prepared on a corrugated catalyst support foil of the present invention. [0033] FIGS. 4A , 4 B and 4 C are scanning electron microscope images of the treated and untreated fibers used in Example 10. [0034] FIG. 5 is composed of two pictures of samples of the plurality of thin steel fibers that can be used to make the fibrous material of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0035] The present invention will be understood by those skilled in the art by reference to the following description of the preferred embodiments including examples and the accompanying drawings. [0036] In a first embodiment, this invention relates to a method for producing thin-layer skeletal catalyst-coated metal and metal alloy structures without applying an intermediate washcoat layer and, in a second embodiment, to a method for generating an adherent oxidic layer on a thin metal foil or fibrous substrate, suitable as a catalyst support, without applying an additional oxide slurry washcoat. Other aspects of this invention relate to the formation and use of specific catalytically active skeletal metal layers whose compositions consist of particular surface alloys or multiple metal mixtures produced by the method of the first embodiment. [0037] FIG. 1 is a schematic of two embodiments of the process for producing the skeletal catalyst-coated thin metal structures of the present invention. In these embodiments, a six inch wide roll of nickel or other metal shim stock, for example, is coated by a slurry prepared by ball milling a mixture containing one or more metal powders or preformed bulk metal alloy powders that are precursors to catalytically active materials. It should be noted that the slurry always contains aluminum powder. The coated nickel roll stock is then introduced into a furnace under a reducing or inert atmosphere wherein at least one of the one or more metals in the slurry interdiffuses with the surface of the nickel roll stock forming an alloy or intermetallic that firmly binds the coating to the nickel substrate. Upon exiting the furnace, the coated metal substrate can be either formed into a desired shape or continue for additional processing before being formed into a desired shape. [0038] Although FIG. 1 and the following disclosure is predominantly directed to the use of thin metal foil as the metal substrate, similar process steps would be used if the metal substrate was a flattened mat of metal fiber or a flattened woven metal fiber assembly. [0039] In the embodiment where the coated metal substrate is a thin metal foil that is formed into a desired shape before any additional processing occurs, the coated metal stock is slit, optionally corrugated, chopped, and assembled upon leaving the furnace to form the desired catalyst structure. The desired catalyst structure may then be assembled into a larger structure, such as by arranging cut pieces and fastening them by methods known in the art to produce a stackable scaffold superstructure. Then, the coated metal pieces are leached in an aqueous caustic solution as a formed shape and subsequently subjected to a chelating acid bath such as a citric acid bath. Following the chelating acid bath, the coated metal pieces are passivated in a bath of a mild oxidant, preferably dilute hydrogen peroxide aqueous solution, and then water-washed and dried. After passivation, but prior to the drying step, formed catalyst structures optionally can be abraded with a high velocity jet of water to remove weakly adhered layers, if any, then dried. Finally, the formed catalyst structures can be packaged. [0040] In another embodiment of the present invention, a conforming oxidic catalyst support layer is formed on the surfaces of the adhered alloy or intermetallic layer (i.e., the layer formed after the one or more metals in the coating slurry interdiffuses with the surface of the metal foil substrate). In this embodiment of the present invention, the intrinsic oxidic catalyst support layer is formed by adding an additional step to the disclosed process. That step involves heating the coated metal substrate (after the leaching step or in place of the leaching step) in an oxygen containing atmosphere (e.g., air) to form an adherent oxide coat (i.e., an intrinsic oxidic layer suitable as a catalyst support layer) directly, without application of an additional washcoat. The additional step preferably occurs in an air calcination unit after the gross form-factor fabrication step, if formed parts are desired. The topologies and specific surface areas of the oxidized surfaces are distinctly different depending on whether or not the leaching step is applied prior to the oxidation step. Thus, the need for inclusion of the leaching step is determined by the requirement for additional surface area or macroporosity in the finished catalyst support structure. [0041] In the embodiment where the coated metal substrate is subjected to additional processing before being formed into a desired shape, the coated metal stock is subjected to a continuous leaching step in an aqueous caustic solution, before being subjected to a chelating acid bath. After the acid bath, the coated metal stock is subjected to continuous passivation by passage through a bath of dilute aqueous hydrogen peroxide solution for a time sufficient to quench any pyrophoricity. The coated metal stock may optionally be subjected to continuous abrasion using a high velocity jet of water (i.e., to cause abrasion of the outer surfaces) after being subjected to the acid bath and before or after the passivation step. After the passivation step, the coated metal stock is then rinsed with water and dried. Acetone rinsing can be used to accelerate drying, but care must be taken to prevent contact of acetone and hydrogen peroxide-containing solutions or residues to avoid formation of potentially explosive compounds. Following the drying step, the coated metal stock is slit, corrugated, and chopped into the desired catalytic elements for the form factor of interest. The desired catalyst elements may then be assembled into a larger scaffold structure, such as by combining (e.g., use of stacking and fastening by methods known in the art) the smaller catalyst elements. Finally, the formed catalytic scaffold structures can be packaged. [0042] In another embodiment of the present invention, a conforming oxidic catalyst support layer is formed on the surfaces of the skeletal metal catalyst layer (including within the macro pores and cracks in the skeletal metal catalyst layer). In this embodiment of the present invention, the intrinsic oxidic support layer is formed by heating the passivated, leached metal substrate in an oxygen containing atmosphere (e.g., air) to form a thicker adherent oxide coat (i.e., an intrinsic catalyst support layer). The additional step preferably occurs in an air calcination unit after the scaffold gross form-factor fabrication step. [0043] Regardless of whether the coated metal substrate is formed into a desirable shape before or after the additional processing steps, the leaching step is performed in a caustic solution, preferably a solution comprising NaOH. As is known in the art, the leaching step selectively removes some of the aluminum and certain aluminides from the coating, forming porosity in the coating, but leaving in place various other aluminide compounds. The temperature of the leaching bath is from about 65 to 95° C., preferably from about 80 to 90° C. The amount of time that the coated metal substrate spends in the leaching bath is from about 5 to 50 minutes, preferably from about 25 to 45 minutes. [0044] The citric acid bath is only one embodiment of the present invention. Suitable acid baths would be those comprising, for example, a mineral acid or carboxylic acid, but polyprotic acids forming chelating anions are preferred The temperature of the acid bath is from about 20 to 40° C., preferably from about 25 to 30° C. The amount of time that the coated metal substrate is held in the acid bath is from about 2 to 10 minutes, preferably from about 3 to 5 minutes. [0045] The use of the intrinsic oxidic catalyst support layer is desirable when very low loadings of precious or platinum metal compounds are necessary or desirable for catalysis or when complex molecular structures with bonded fragile ligands are required rather than bare zero-valent base metals. Deposit of such materials directly onto a reactive base metal substrate, in the absence of an inert oxidic layer, could displace ligands or bury the precious or platinum metal catalytic top layer as the metallic surface restructures with use. Furthermore, the chemical selectivity of the composite metal surface catalyst would be altered by the presence of the dominant reactive metal of the substrate. Thus, an intrinsic, catalytically inert oxidic catalyst support layer can act similarly to a ceramic washcoat layer known in the art to disperse such catalytic species without altering their site-specific activities. [0046] Although lacking some of the advantages of a self-supported thin layer skeletal metal catalyst surface coating, the conforming oxidic catalyst support layer is well adhered to the underlying substrate. Moreover, the intrinsic oxidic catalyst support layer is straightforwardly produced after the gross-form fabrication step so as not to be damaged by mechanical processing. Once impregnated with active catalyst species, the uniform thickness of the intrinsic oxidic catalyst support layer also promotes uniform temperature distribution to reduce the probability of damage from localized hot spots when structured catalysts are used to promote exothermic reactions such as the initiation of catalytic combustion of organic vapors in an oxygen-rich gas. [0047] In another embodiment of the present invention, catalyst alloy compositions have been created according to the disclosed methods that are highly active and hydrothermally stable. The alloy compositions were prepared using nickel foil substrates. The catalyst series investigated on nickel substrates is based on compositions chosen using two-part, three-level partial factorial designed experiments that were pre-planned to screen initial suitability for ternary alloys of nickel, aluminum, and a refractory metal. One of the refractory metals selected was zirconium. Pre-alloyed nickel-zirconium powders were used in some cases. The other refractory metals in the screening experiments were selected based on three criteria: having an elemental melting point significantly greater than nickel, having the ability to form a ternary aluminide with nickel at a relatively low temperature, and having a relative bulk cost lower than that of zirconium. [0048] The other refractory metals (i.e., other than zirconium) selected were nickel (control), vanadium, chromium, titanium, tungsten, niobium, molybdenum, and tantalum. Replicates of each catalyst were prepared by coating the nickel foil substrates with slurries that (when dried) contained the refractory metal at nominally 0, 5, and 11 weight percent loading (i.e., based on the weight of all of the metals in the applied slurry) for screening purposes. After the furnacing step, all formulations were judged to be pliable and durable enough for mechanical corrugation and formation into honeycombs except several containing titanium. Modified compositions of the titanium catalysts that contained slightly lower aluminum content were found to be acceptably pliable and durable towards bending and corrugation directly after the furnacing step. Screening of the metal supported catalyst containing the various alloy compositions was performed to determine fitness-for-use. Screening included analysis of: (1) relative activity in a low pressure hydrocarbon reforming reaction conducted in a quartz microreactor under a particular set of conditions; and (2) BET surface area retention after steam deactivation to measure extent of sintering. Table 1 shows the initial conversion (i.e., percent conversion of total carbon atoms in the reactant feed per total geometric area in cm 2 of the catalyst) for mixed light hydrocarbon reforming (in a laboratory reactor) for catalysts prepared according to the disclosed process. [0000] TABLE 1 Initial Conversion per geometric area Catalyst Coating Compositions For Ni-only and Ni alloy catalysts Ni-shim No Coating 0.57 Al—Ni—Ni only Al(59.4%)—Ni(39.6%)—B(1%) 0.87 Ni—Zr-11% Al(52%)—Ni(36%)—Zr(11%)—B(1%) 1.50 Ni—Cr-11% Al(52%)—Ni(36%)—Cr(11%)—B(1%) 1.61 Ni—Ti-11% Al(52%)—Ni(36%)—Ti(11%)—B(1%) 1.54 Ni—V-11% Al(52%)—Ni(36%)—V(11%)—B(1%) 1.27 Ni—Ta-11% Al(52%)—Ni(36%)—Ta(11%)—B(1%) 1.45 Ni—Zr-5% Al(56%)—Ni(38%)—Zr(5%)—B(1%) 1.63 Ni—Cr-5% Al(56%)—Ni(38%)—Cr(5%)—B(1%) 1.41 Ni—Ti-5% Al(56%)—Ni(38%)—Ti(5%)—B(1%) 1.23 Ni—V-5% Al(56%)—Ni(38%)—V(5%)—B(1%) 1.38 Ni—Ta-5% Al(56%)—Ni(38%)—Ta(5%)—B(1%) 1.24 [0049] Table 2 (below) shows the BET surface area before and after steam deactivation. Because both initial activity and resistance to deactivation are important for optimal performance, Ni—Zr and Ni—Cr alloys and higher loading of Ni—Ta are preferred compositions. The remaining multimetallic alloy catalysts also perform better than non-alloyed foraminous nickel compositions or compositions with added nickel plus aluminum only on the nickel substrate. The first entry in Table 2 was prepared by coating a nickel substrate with only aluminum as the metallic component of the coating slurry. The last entry in Table 2 was prepared by adding only aluminum, boron and nickel to the coating slurry but no other metallic components. [0000] TABLE 2 BET Surface Area Analysis of Multimetallic Alloy Catalyst Coatings (not passivated) Coating compositions Surface Area Before Steaming 1 Surface Area After Steaming 2 Al(58.7%)—Ni (40.3%)—B(1%) 83 5 Al(52%)—Ni(36%)—Zr(11%)—B(1%) 152 26 (RG-49-78) Al(52%)—Ni(36%)—Zr(11%)—B(1%) 153 29 Al(52%)—Ni(36%)—Cr(11%)—B(1%) 100 21 Al(52%)—Ni(36%)—Ti(11%)—B(1%) 75 9 Al(52%)—Ni(36%)—V(11%)—B(1%) 156 31 Al(52%)—Ni(36%)—Ta(11%)—B(1%) 132 25 Al(56%)—Ni(38%)—Zr(5%)—B(1%) 158 27 Al(56%)—Ni(38%)—Cr(5%)—B(1%) 175 20 Al(56%)—Ni(38%)—V(5%)—B(1%) 151 30 Al(56%)—Ni(38%)—Ta(5%)—B(1%) 146 24 Al(59.4%)—Ni(39.6%)—B(1%) 133 19 1 = Surface Area measured by BET (m 2 /g coating). All values are average of values obtained for two batches of samples except for RG-49-78. 2 = Surface Area measured by BET (m 2 /g coating). All values are single values from one batch. [0050] Additional independent characterization experiments were conducted to further differentiate the multimetallic formulations of this invention from those that did not include refractory alloy metals and from a commercial methane steam reforming catalyst comprising a nickel oxide on a ceramic support. Accordingly, passivated catalysts were reduced in situ prior to measuring their hydrogen chemisorption capacities by a flood adsorption/temperature programmed desorption method, a method known in the art. These data were compared to similar measurements on ground and sized commercial nickel-based ceramic catalyst pellets (Hi-Fuel 110, Alfa-Aesar Johnson-Matthey Co.). Standard algorithms in commercial software that account for differences in metal loading were used to estimate dispersions and metal areas derived from the hydrogen chemisorption data obtained. As shown in Table 3, replacing nickel with either 11% (by weight) zirconium or chromium resulted in increased hydrogen binding capacity, which translates to greater apparent dispersion, and in greater exposed metal area, directionally consistent with earlier BET measurements. The specific surface areas and dispersions of nickel computed for fresh (passivated) multimetallic catalysts of this invention are slightly higher than those areas measured for fresh Hi-Fuel-110 commercial catalyst after similar pre-reduction. [0000] TABLE 3 Apparent Dispersion Measured by a Hydrogen Flood Adsorption/Temperature Programmed Desorption Method After a Temperature Programmed Reduction Step Average Apparent % Dispersion after TPR Composition of Original (assume 0.5 stoichiometry for Catalyst Sample Coating all coated metal content) Hi-Fuel-110 (Alfa-Aesar) Unknown 7.8 ZrNi passivated Al(52%)—Ni(36%)—Zr(11%)—B(1%) 12.0 ZrNi steamed Al(52%)—Ni(36%)—Zr(11%)—B(1%) 2.5 CrNi passivated Al(52%)—Ni(36%)—Cr(11%)—B(1%) 10.3 CrNi steamed Al(52%)—Ni(36%)—Cr(11%)—B(1%) 1.7 Ni only passivated Al(59.4%)—Ni(39.6%)—B(1%) 8.4 Ni only steamed Al(59.4%)—Ni(39.6%)—B(1%) 2.3 Example 1 [0051] An 11% Zr—Ni multimetallic catalyst (designated as RG-49-78) was prepared as described below. First, a 900 mL slurry containing 611 g of Al powder (10 micron average particle size), 109.1 g of Ni powder (Conductive Nickel Pigment type 525 D, −250 mesh obtained from Novamet), 444.3 g of Zr/Ni alloy (30/70; obtained from Chemetall), 10.1 g boron powder (elemental amorphous boron 95%; 0.5 to 3 microns; obtained from CR supply), 20.9 g of methyl methacrylate based binder, and 397.1 g of acetone were milled in a ball mill for about 12 hours with 150 mL of ¼ inch steel balls. The resultant slurry was then applied by dip coating to a Ni shim stock substrate (nominally 2 mil thick) that had been pre-cleaned with acetone and the resulting slurry coating thickness ranged from 5.75 to 6.25 mil. After drying in a hot air stream, the coated substrate was passed through a four foot long furnace fitted with an open-ended retort at a speed of 12 ft/min. The temperature in the furnace was 750° C. and the atmosphere was hydrogen gas (the hydrogen gas flow rate to the furnace was 200 SCFH). After exiting the furnace, the coated substrate was leached in a 200-225° F. aqueous solution containing 25% NaOH for 45 minutes and then rinsed with water. The coated substrate was then bathed in a citric acid solution (5% by weight citric acid in water) for 3 minutes and then again rinsed with water. The coated substrate was then passivated by immersion in an aqueous solution containing 3% (by weight) H 2 O 2 for 12 minutes and subsequently rinsed with water again. Finally, the coated substrate was rinsed with acetone and dried with nitrogen gas. [0052] The catalyst demonstrated an initial (passivated) surface area of 151 m 2 /(g-coating), and aliquots were subjected to successive steaming periods or to successive periods of attrition using a high pressure water jet. Durability was judged by monitoring weight loss versus attrition time (see Table 4 below) and versus jet pressure and by monitoring SEM thickness measurement after cross sectional polishing (see Table 5 below). Weight loss and surface area measurement were also made after successive periods of steaming at 900° C. [0000] TABLE 4 Weight Losses of a Zr—Ni Catalyst After Successive Periods of Steaming or Water Jet Abrasion Steaming of High Pressure Water Jet RG-49-78 RG-49-78 at 900° C. (about 1880 psi at max nozzle setting) Treatment Treatment Time (hr) % Weight Loss Time (sec) % Weight Loss 2 4.04 30 9.93 3 5.36 150 10.27 6 3.13 300 8.74 9 3.76 — — [0000] TABLE 5 SEM Coating Thickness Measurements of Distinct Layers in Fresh, Steam-Aged and Used Catalysts Inner Coating Total Coating (one side- Sample (By SEM) (μm) by SEM) (μm) RG-49-78 7.5 ± 1.6 45.8 ± 7.3 Fresh RG-49-78 7.4 ± 1.3 28.1 ± 7.0 Steamed at 900° C. for 9 hours RG-49-78 10.1 ± 2.0  33.6 ± 6.8 Used [0053] Successive abrasion of the catalyst resulted in an initial weight loss of the friable material that leveled out after an 8-9% by weight loss. Steaming for various periods up to 9 hours results in smaller weight losses that did not continue to increase after the initial loss. Scanning electron microscope (SEM) measurement of the polished cross sections strongly supports the conclusion that initial attrition is due to loss of a relatively loosely bound outer surface layer, but that no or little loss occurs in the highly active inner core that appears to be the diffusion layer, which is firmly affixed to the metal substrate. [0054] Table 6 (below) shows the relative initial hydrocarbon reforming activity (i.e., percent conversion of total carbon atoms in the reactant feed per total geometric area in cm 2 of the catalyst) of the same catalyst type (identified as RG-49-78) after attrition and shows BET surface areas before and after steaming. The inner core, exposed after attrition, is just as or more active than the fresh catalyst within experimental error. Thus, the catalyst is shown to remain stable and extremely active after an initial loss of outer layer. Moreover, deactivation does not progress linearly with continuing time of exposure to highly abrasive conditions or to conditions that facilitate rapid sintering. Further, no detectable phase change (determined from DTA/TGA data) exists at high temperature after the initial reduction of the passivation oxide. Reduction of the oxide accounts for a large portion of the weight loss observed on stream. FIGS. 2A , 2 B and 2 C show the effectiveness of steaming at simulating the sintering encountered during aging of the catalyst on-stream as evidenced by the loss of sharp edges of crystallites and formation of spherical structures in similar fashion. [0055] Also, as shown in Table 6, the BET surface areas of the resulting materials are similar after steaming and after extended exposure to process conditions. [0000] TABLE 6 Initial Light-Hydrocarbon Reforming Activity After Increasing Periods of Catalyst Attrition, and BET Surface Areas After Increasing Periods of Steaming Compared to Used Catalyst BET SA Passivated- BET SA Passivated Steamed Sample Treatment Time Xc/geometric area (m 2 /g coating) (m 2 /g coating) RG-49-78  0 sec 1.40 — — (previous batch) Reference RG-49-78  30 sec 1.21 — — (pressure washed) RG-49-78 300 sec 1.52 — — (pressure washed) RG-49-78 2 hr — 147 16 (previous batch) Reference RG-49-78 6 hr — — 14 (steamed at 900° C.) RG-49-78 9 hr — — 15 (steamed at 900° C.) RG-49-78 — — — 14 Used Example 2 [0056] An experiment was run where an 11% Zr/Ni/Al/B/Ni catalyst was prepared for use in a steam methane reforming reaction, according to an embodiment of the methods disclosed in the present invention. First, a 900 mL slurry containing 611.0 g of Al powder (10 micron average particle size), 109.1 g of Ni powder (Conductive Nickel Pigment type 525 D, −250 mesh obtained from Novamet), 444.3 g of Zr/Ni alloy (30/70; obtained from Chemetall), 10.1 g of boron powder (elemental amorphous boron 95%; 0.5 to 3 microns; obtained from CR supply), 20.9 g of methyl methacrylate based binder, and 397.1 g of acetone were milled in a ball mill for about 12 hours with 150 mL of ¼ inch steel balls. The resultant slurry was then applied by dip coating to a Ni shim stock substrate (nominally 2 mil thick) that had been pre-cleaned with acetone and the resulting slurry coating thickness ranged from 5.75 to 6.25 mil. After drying in a hot air stream, the coated substrate was passed through a four foot long furnace fitted with an open-ended retort at a speed of 12 ft/min. The temperature in the furnace was 900° C. and the atmosphere was hydrogen gas (the hydrogen gas flow rate to the retort was 200 SCFH). After exiting the furnace, the coated substrate was leached in a 200-225° F. aqueous solution containing 25% NaOH for 45 minutes and then rinsed with water. The coated substrate was then bathed in a citric acid solution (5% by weight citric acid in water) for 3 minutes and then again rinsed with water. The coated substrate was then passivated by immersion in an aqueous solution containing 3% (by weight) H 2 O 2 for 12 minutes and subsequently rinsed with water again. After the H 2 O 2 treatment, the coated substrate was then abraded with a high velocity jet of water at 1880 psi for 2 minutes on each side with the coated substrate fixed at 3 inches distance from the nozzle of the water jet. The water jet abrasion caused the coated substrate to lose approximately 3.9% of its mass. Finally, the coated substrate was rinsed with acetone and dried with nitrogen gas and then passivated by immersion in an aqueous solution containing 3% (by weight) H 2 O 2 for 12 minutes and subsequently rinsed with water again then dried in air. Example 3 [0057] Scanning electron microscope images (SEM) were taken of fresh, steamed and used catalytic foils derived from the same preparative batch described in Example 2. The used samples had been exposed to SMR process conditions for several hundred hours prior to imaging. In the images, the outer layer appears less prominent and highly diminished in thickness with aging. The inner core however remains adhered and highly reactive either after the steam treatment or after being used under process conditions for several hundred hours. Example 4 [0058] A sample of zirconium-nickel foil composition, prepared according to the method described in Example 2, that had been furnaced at 900° C. under hydrogen, anaerobically leached, citric acid treated, passivated and pre-attrited using a high pressure water jet, and then dried, was tested for steam methane reforming performance. In a packed-bed plug-flow integral conversion reactor, operating under commercially viable steam methane reforming conditions, instantaneous on-line analytical measurements of product composition and corresponding temperature differentials between applied temperature at the reactor wall and the catalyst surface were used to compute activity versus time. Bulk heat and mass transfer effects on activity that could be attributable to form factor differences were excluded in these tests by using similarly sized foil slivers embedded in inert packing rather than using monolithic form factors. However, intraparticle (molecular scale) mass transfer effects, dependent on the surface nanostructures of the foils, still could influence relative performance. [0059] In this test, the catalyst foil not only generated higher volumetric activity than the reference catalyst, a ceramic-supported nickel oxide of a type used commercially, but also survived 900 hours without deactivation or significant physical degradation. [0060] The following examples demonstrate the effectiveness of the coated foils or fibers of the present invention to act as catalyst supports for promoted precious or platinum group metal catalysts. The substrate metal used to produce these catalysts was 430 grade stainless steel (a well-known alloy that contains no significant amounts of aluminum or yttrium). The 430 grade stainless steel alloy is a preferred metal substrate material for the catalysts of the present invention, especially when those catalysts need to be resistant to high temperatures (e.g., temperatures in the range of 800 to 1,000° C.). Example 5 Preparation of Catalyst Supports [0061] 430 alloy grade stainless steel foil shim stock, 2 mil thick, was obtained from Ulbrich Co. of North Haven, Conn., USA as 4 inch wide pieces. These were cut into flat strips measuring approximately 1.5 inch by 8 inch and washed with acetone. Each of several strips was coated with a slurry using a laboratory-scale falling-film “dip coater” then dried by hanging in a heated air stream. The coating slurry was composed as follows: [0000] aluminum powder (about 3 μm average particle size): 57.8 wt % methyl acrylate based binder: 4.2 wt % Acetone: balance [0062] After drying, the coated strips were stapled to leaders of metal foil and passed through a 4 foot long retort housed in a clam shell furnace held at 730° C. at 6 feet per minute under flowing hydrogen, then cooled in air. The coating appeared uniform and adherent at this point. The “hydrogen furnaced” intermediates were placed in a box furnace on a ceramic fixture that allowed air circulation on both sides of the foil strips and were heated in static air with the following schedule: room temperature to 650° C. ramped at 20°/min then held at 650° C. for 1.5 hours. The samples were allowed to cool in the box furnace over about 1.5 additional hours. The resulting oxidized strips were flexible, with the coating remaining intact after flexure. Example 6 Catalyst Preparation A: Ce/Cu/Pd/Pt Catalyst [0063] Support strips that were prepared as described in Example 5 were cut into smaller pieces of 25 by 80 mm dimensions and impregnated with catalytic agents as described below. [0064] Ammonium hexanitrocerate (IV), (NH 4 ) 2 Ce(NO 3 ) 6 (0.3958 g), and copper (II) acetate hydrate (0.0262 g) were dissolved into 0.5 mL of distilled water with sonication, then acetonitrile (0.11 g) was added to form a lime green solution. The support strip was placed on a watch glass and wet with the Ce—Cu solution on both sides. Excess solution was tapped off the metal strip back onto the watch glass, then the wet strip was dried for several minutes in a hot air stream. After drying, the sequence of impregnation and drying was repeated two more times until the solution had been depleted. The dried strip was calcined in a static box furnace in ambient air and heated by ramping at 20° C./minute to 500° C., then held at this temperature for 30 minutes and then cooled. The cooled strip was lightly wiped with a laboratory tissue then blown clean with a compressed air nozzle to remove a small quantity of loose powder from the surface. The strip then was impregnated with palladium and platinum salts as described below. Dichlorotetraaminepalladium (II) monohydrate, Pd(NH 3 ) 4 (Cl) 2 .H 2 O (0.0766 g) and tetraamineplatinum (II) nitrate, Pt(NH 3 ) 4 (NO 3 ) 2 (0.0367 g) were dissolved into 0.5 mL of distilled water without pH adjustment. The strip was wet with the Pd/Pt solution as described above, then the strip was dried in a hot air stream. The wetting/drying sequence was repeated carefully until the entire quantity of solution had been consumed. The dried strip was calcined in a box furnace in air by heating at 20° C./min to 500° C., then held at 500° C. for 2 hours and then cooled slowly in the furnace. The sample was lightly wiped with laboratory tissue then blown clean with compressed air. Weight measurement showed that the sample had gained weight in the coating-calcining-wiping process. Based on the assumptions of retention of applied molar ratios, the composition of expected reaction product phases, and the actual final weight gain, the nominal catalyst composition was computed as 5.56% CeO 2 , 0.51% CuO, 0.828% Pt, and 1.59% PdO. Example 7 Catalyst Preparation B: Ce/Pd/Pt Catalyst [0065] A second catalyst was prepared as above (i.e., as described in Examples 5 and 6), except the copper salt and acetonitrile components were excluded from the formulation, only one calcination step was included, and the following quantities of precursor materials were used for a similarly sized support strip: [0000] (NH 4 ) 2 Ce(NO 3 ) 6 0.380 g Pt(NH 3 ) 4 (NO 3 ) 2 0.030 g Pd(NH 3 ) 4 (Cl) 2 •H 2 O 0.075 g Example 8 Catalyst Preparation C: Pd/Pt Catalyst [0066] A third catalyst was prepared as above (i.e., as described in Examples 5, 6 and 7), except both the cerium and copper salts and the acetonitrile components were excluded from the formulation, only one calcination step was included, and the following quantities of precursor materials were used for a similarly sized support strip: [0000] Pt(NH 3 ) 4 (NO 3 ) 2 0.028 g Pd(NH 3 ) 4 (Cl) 2 •H 2 O 0.074 g Catalyst Testing for Oxygen Depletion [0067] Each of the three catalysts described above (i.e., A, B and C), were tested in a laboratory scale oxygen depletion reactor screening test to determine their relative “light off” temperature performance. The test is conducted by passing a precise flow rate of a particular gaseous reactant solution containing a hydrocarbon (heptane) and oxygen over a fixed size of coiled, corrugated catalytic foil. Oxygen is the limiting reagent. As the temperature is ramped upwards at a precisely controlled rate, the product stream is continually analyzed for residual oxygen content. The isokinetic temperature (i.e., corrected for the time delay of transport between the reactor and the analyzer) at which point 50 mol % conversion of oxygen has occurred, termed T 50 , is noted and used as a comparative measure of “light off” performance. Other features of importance are the initiation temperature and the shape and slope of the extinction curves (mathematically related to catalytic reaction rate) relative to those observed over other catalysts. Reaction rate data are normalized to reactor bed volume and to total exposed geometric surface area of catalytic foil. The test conditions used are described in Table 7 (below). [0000] TABLE 7 Catalyst size/form coiled, corrugated foil of 25 by 80 mm dimensions before corrugation Catalyst geometric area 40 cm 2 Feed composition O 2 : 1.1%; n-C 7 H 16 : 21.15%; Ar: 27.19% (internal standard); N 2 : balance T ramp 7° C./min; 25 to 370° C. (typical) GHSV 1 (based on total reactor vol) ~8400 h −1 Hourly Face Velocity (based on actual 275.9 cm/h area on both sides of catalyst) Reaction overall stoichiometry C 7 H 16 + 11 O 2 → 7 CO 2 + 8 H 2 O Static pressure Barometric Analytical quadrupole mass spectral analysis of O 2 partial pressure at m/e = 32.0 1 The GHSV (gas-hourly-space-velocity) was calculated at 25° C. and 760 torr. The reactor volume is computed as if it were a fully filled cylinder with no void volume between portions of catalyst. [0068] Catalysts often equilibrate with repeated use as the Pt/Pd species on the surface adjust oxidation state ratios (reduce or oxidize) to achieve a steady-state condition. In this test, changes occur over 2-3 runs during which time their T 50 values typically move to lower values and their curve shapes become more symmetrical and often steeper in extinction of oxygen (catalysts get better). When time permits, the third run over each catalyst usually is taken as the definitive result for that particular composition in our laboratory. [0069] Table 8 (below) and FIG. 3 summarize the corrected data for the catalysts prepared as described above in Examples 6, 7, and 8. In FIG. 3 , the y-axis values represent the O 2 partial pressure (in torr) measured by a mass spectrometer (i.e., determined from the O 2 signal at m/e=32). The x-axis values are the corrected catalyst temperature (i.e., isokinetic temperature; approximately two degrees celsius lower than measured temperature at catalyst bed) in degrees celsius”. [0070] Note that addition of cerium lowers the temperature at which the catalyst initiates the “light off” but does not affect the T 50 much. The co-addition of a copper component in addition to the cerium promotes an even lower temperature for initiation of the reaction and dramatically reduces T 50 as well. Table 8 (below) summarizes the quantitative data: [0000] TABLE 8 Example Run T 50 (° C.) (lower is better) 6-Catalyst Preparation A 1 209 [Ce/Cu/Pd/Pt] 7-Catalyst Preparation B 3 245 [Ce/Pd/Pt] 8-Catalyst Preparation C 3 247 [Pd/Pt] Fibrous Material Embodiment [0071] In a preferred embodiment of the present invention, thin metal fibers, such as thin 430 stainless steel fibers, are used as the starting material upon which aluminide and aluminum oxide layers are formed to create a fibrous material that functions as an effective catalyst support for platinum group or other metals. After impregnation with catalytic agents, this catalytic fibrous material (which can withstand high temperatures, for example from 600-900° C.) can be used in soot traps for diesel engines or in catalytic converters. For example, the catalytic fibrous material (e.g., containing a PGM catalyst) can be used to create a self-oxidizing partial diesel particulate filter (i.e., a partial diesel particulate filter conforms to the requirement for soot trapping efficiency of greater than 50% but less than 80%) featuring partial bypass of flow to ensure even loading of soot and to reduce pressure drop. [0072] Catalytic soot traps filter carbonaceous soot particles from exhaust streams under rich combustion conditions and ignite and burn off the soot under lean combustion conditions via catalytic initiation of oxidation. [0073] Most catalytic soot trap devices comprise a refractory oxide particle layer that is applied directly to a ceramic or metallic substrate before the catalytic species is applied. The refractory oxide particle layer is commonly referred to as a “washcoat,” and its application is followed by application of the PGM components. The washcoat typically comprises high surface area oxides, such as, for example, transition-phase aluminum oxides, that stabilize and disperse the catalytic components (i.e., they maintain the specific surface area of the catalytic components under process conditions, without becoming volatile or detrimental to the catalytic species). The PGM, or other catalytic components, can then be applied in a second impregnation step over the cured washcoat layer, or can be added directly to the slurry of the washcoat particles (and adsorbed thereon) prior to coating of the metallic or ceramic substrate forms in a single coating step. The washcoat components may also comprise hydroxide precursors that cross-link during curing to form oligomers characterized by bridging oxygen groups. While the cross-linking improves adherence to the substrate, the washcoat is not directly covalently bonded to the metallic substrate. [0074] Regardless of the specific composition, high solids content viscous slurries of washcoat materials are difficult to apply in uniform thickness over small formed openings or open channels that are part of the pre-shaped substrate structures. When metal supported catalysts are used to catalyze exothermic processes such as combustion, hot spots can arise if the washcoat, and the catalytic layer supported thereon, is not applied uniformly. Hot spots lead to accelerated failure of substrate materials as well as to deactivation of the catalytic components. Thus, uniform coating of substrate structures facilitates the production of durable catalytic devices. [0075] In addition to challenges associated with application of the washcoat layer, the constituent materials used to prepare substrates (monoliths), whether ceramic or metallic, must be able to withstand severe processing conditions. These constituent materials must also be suitable for fabrication into form-factors that can trap soot without too high a pressure drop. The materials used to prepare substrates must also be compatible with the chosen washcoat layer to avoid delamination of this layer. Heat conduction, cost and corrosion-resistance in the presence of acidic gases such as sulfur oxides and steam are also important factors to consider when choosing substrate materials. [0076] Metallic substrates are sometimes preferred over ceramic substrates because they can more easily be formed into complex shapes and/or because they are better at heat conduction. On the other hand, ceramics are sometimes preferred over metallic substrates due to the fact that many metals are easily corroded or destructively oxidized under severe process conditions. High alloy metals that are corrosion and oxidation resistant do find use as catalyst supports, but they are limited to high value added applications because of their high cost. [0077] When metallic substrates are used, practitioners often employ high temperature stable alloys such as Fecralloy™. Due to its composition, Fecralloy™ generates, upon exposure to air, a thin aluminum oxide layer on the external surface of the metallic substrate that is protective against corrosion and oxidative degradation. The protective layer differs from washcoat oxide layers—which are designed to be porous—in that it is thinner and less pervious. [0078] Unfortunately, fibrous forms of Fecralloy™ are expensive and difficult to work with. For example, some metal oxide washcoats adhere poorly to this alloy when applied by the usual slurry process without prior treatment of the surface. Many other metals such as corrosion-resistant high alloy steels can be used for high temperature applications, but these are extremely expensive or are too brittle to easily fabricate into coiled structures of appropriate fiber density needed for efficient small particle filtration. [0079] Based on the aforementioned challenges, it would be desirable to provide a metallic material (and process for its production) for use as a catalyst substrate that exhibits good heat conduction, is corrosion resistant, is oxidation resistant, and provides for a uniformly distributed, and highly adherent, oxide layer. Such material should also be capable of being formed into a fibrous form factor (e.g., a monolith honeycomb; or a packed fiber body; or parallel plates) that is suitable for coating with platinum group metal catalytic components and that is suitable for fabrication into soot traps for diesel engines. [0080] The catalytic soot trap embodiment of the present invention comprises a fibrous material comprising a highly adherent aluminum oxide outer layer of substantially uniform thickness. The aluminum oxide outer layer of the fibrous material acts as an intrinsic support for catalytic moieties, such as platinum group metal (PGM) catalytic moieties. The fibrous material of the instant invention is malleable enough to be fabricated into a low pressure-drop form factor, exhibits good heat conduction, is corrosion resistant and is resistant to oxidation. In addition to being used as a soot trap for diesel engines, the fibrous material (after the inclusion of the PGM) can also be used in catalytic converters. [0081] In one aspect of the catalytic soot trap embodiment of the present invention, the fibrous material comprises a plurality of thin steel fibers comprising a chromium-iron alloy, an interdiffusion layer (also referred to herein as an aluminide layer) covering at least a portion of the surfaces of the plurality of thin steel fibers, and an aluminum oxide outer layer that adheres to, and interfaces with, the interdiffusion layer. The interdiffusion layer (also referred to herein as the aluminide layer) may comprise aluminum, substrate metal (here steel) and aluminides (i.e., intermetallics of aluminum and the substrate metal or metals contained in the substrate metal). In a preferred embodiment of the present invention, the aluminide layer covers most of the surface of the plurality of thin steel fibers and the aluminum oxide outer layer covers most of the surface of the aluminide layer. [0082] The aluminum oxide outer layer has a substantially uniform thickness. In addition, this layer is sufficiently thick enough to act as a suitable support layer for catalytic moieties such as platinum group metal catalytic moieties and also provides protection against oxidation and corrosion. In a preferred embodiment of the present invention, the aluminum oxide outer layer is highly adherent to the aluminide layer. [0083] The plurality of thin steel fibers is usually in the form of a pliable metal fiber bundle and comprises Type 430 or Type 434 steel. Furthermore, the plurality of thin steel fibers are typically able to retain ductility after being heated in air to temperatures of about 600° Celsius to about 900° Celsius. [0084] The fibrous material of the present invention can be made by a method comprising the following steps: (a) obtaining a plurality of thin steel fibers comprising a chromium-iron alloy; (b) applying an aluminum coating onto the plurality of thin steel fibers; (c) forming an aluminide layer by partially interdiffusing the aluminum from the aluminum coating into the surface of the plurality of thin steel fibers by heating in a diffusion furnace under an inert or reducing atmosphere; and (d) forming an aluminum oxide outer layer (i.e., on the surface of the aluminide layer) having a substantially uniform thickness by subjecting the residual surface aluminum and aluminide layers to high temperature oxidation (e.g., in an oxidation furnace) in the presence of an oxidizing gas such as air. [0089] The aluminum coating is typically formed from a slurry that comprises an aluminum powder and a binder. The aluminum coating can also comprise a stabilizer such as cerium oxide or other rare earth salts. The aluminum coating is usually applied to the plurality of thin steel fibers using a continuous falling film coater followed by a drying step. [0090] The interdiffusion of the aluminum from the aluminum coating into the surface of the metal fibers takes place in a diffusion furnace at a temperature of from about 640 to 1,100° C., preferably from about 650 to 900° C., under a hydrogen atmosphere for a time of from about 0.2 to 4 minutes, preferably from about 0.3 to 1 minute. [0091] The plurality of thin steel fibers containing an aluminide coating is usually heated in the oxidation furnace to a temperature of about 600° Celsius to about 950° Celsius for about 5 to about 120 minutes. In a preferred embodiment of the present invention, the aluminide coated fibers are heated in the oxidation furnace to a temperature of about 800° Celsius to about 950° Celsius for about 10 to about 15 minutes. [0092] The fibrous material of the present invention can be made into a filter (e.g., a catalytic filter) by a method which includes performing steps (a) through (d) above and then steps (e) and (f) as described below: (e) impregnating the plurality of thin steel fibers bearing the aluminide and aluminum oxide layers with a platinum group metal catalyst so as to infiltrate at least a portion of the aluminum oxide layer with the platinum group metal catalyst; and (f) forming a filter from the fibrous material obtained from step (e). [0095] Another method of making a filter according to the present invention comprises performing steps (a) to (d) as described above and then steps (e) and (f) as described below: (e) forming a filter from the fibrous material obtained in step (d); and (f) impregnating the filter obtained in step (e) with a platinum group metal catalyst so as to infiltrate at least a portion of the aluminum oxide layer with the platinum group metal catalyst, optionally followed by calcination. [0098] The fibrous material comprising the aluminum oxide outer layer does not disintegrate (e.g., no delamination of the aluminum oxide coating) when subjected to substantial temperature changes, exhibits good heat conduction, is oxidatively stable (as measured by thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC), and/or long temperature soaks in a heated air environment), and is not excessively brittle (i.e., it is malleable enough to be fabricated into a low pressure-drop form factor). [0099] Experiments performed to measure the oxidative stability, measured by a thermogravimetric analysis (i.e., TGA), of two samples of fibrous materials showed that one of the samples (Sample 2), which was a coated fibrous material according to the instant disclosure, was more oxidatively stable in air at temperatures exceeding 1,000° Celsius than the other sample (i.e., Sample 1), which was an uncoated stainless steel fiber mat. Specifically, the two samples were tested for oxidative stability by heating the samples in flowing air (50 mL/min) from room temperature to 1,200° C. at a ramp rate of 20° C. per minute. In this oxidative stability experiment, the sample according to the present invention (i.e., Sample 2; a mat of thin steel fibers bearing a uniform aluminum oxide coating that is adhered to and interfaces with an aluminide layer) showed a weight gain just 1.4%, whereas the other sample (i.e., Sample 1; a mat of uncoated stainless steel, alloy 434, fibers) showed a weight gain of 9.2% under the same oxidation conditions. Sample 2 was made by the process described below. [0100] A ¼ inch thick×2 inch wide 430 stainless steel fibrous mat (obtained from Ribbon Technology Corporation) was cut into strips measuring approximately 2 inch by 8 inch and those strips were cleaned with acetone. Each of the strips was coated with a slurry using a laboratory scale dip coater and then dried by hanging in a heated air stream. The coating slurry was composed of: (a) 58% by weight aluminum powder (about 3 micron average particle size); (b) 4% by weight methyl methacrylate (as a binder) and (c) 38% by weight acetone. After the drying step, the coated strips were stapled to leaders of metal foil and passed through (at six feet per minute) a four foot long retort housed in a clam furnace held at 710° C. The atmosphere in the furnace was flowing hydrogen. After emerging from the furnace, the samples were cooled in the ambient air. The hydrogen furnaced samples were then oxidized using a batch process wherein the samples were placed in a box furnace and heated in static air using the following oxidation conditions: room temperature to 630° C. ramped at about 5° C. per minute and then held at 630° C. for two hours before the temperature was ramped from 630° to 850° C. at about 2.4° C. per minute and held at 850° C. for two hours. The samples were then cooled to room temperature in ambient air. The resultant samples were flexible. [0101] In a preferred embodiment of the present invention, the fibrous material of the instant disclosure is made by first obtaining coarse, medium, or fine grade 430 or 434 chromium-iron alloy stainless steel coiled mats of a suitable width and thickness, wherein each mat comprises a plurality of bundled thin steel fibers. FIG. 5 depicts two samples (ASC54-18-1 and ASC54-18-2) of the plurality of thin steel fibers (shaped into loose mats) that can be used to fabricate the fibrous material of the instant disclosure. The dimensions of these samples are shown below in Table 9. [0000] TABLE 9 Length Width Height Sample ID (inches) (inches) (inches) Volume (in 3 ) ASC54-18-1 1.75 2.25 0.25 0.98 ASC54-18-2 2.75 1.75 0.25 1.20 [0102] In addition, FIG. 4A shows an SEM image of an individual thin steel fiber (i.e., untreated; as received) used to make the fibrous material of the present disclosure. The plurality of thin steel fibers comprises a chromium-iron alloy stainless steel that usually comprises about 14% to about 18% chromium. In addition, the mat of fibers is typically about ⅛ to about ½ inches thick and about 2 to about 4 inches wide, although wider mats of fibers can be used if desired. [0103] Next, the plurality of thin steel fibers are coated with an aluminum coating. The aluminum coating is typically in the form of a slurry that comprises an aluminum powder, a binder (e.g., a methyl acrylate-type binder) and a solvent (e.g., acetone). The slurry may also comprise a stabilizing component such as cerium oxide or other rare earth salts. Usually, the slurry is ball milled with stainless steel balls overnight and is continuously stirred during the coating process. [0104] Coating of the plurality of thin steel fibers with the aluminum coating is typically accomplished using the falling film method. The speed at which the plurality of thin steel fibers rise, and the length of the zone before the dryer, can both be adjusted according to skills known in the art to generate a substantially uniform coating of a desirable thickness. [0105] After the aluminum coating has been applied, the plurality of thin steel fibers move vertically through a drying section to set the binder. Once the binder is set, the plurality of thin steel fibers are subjected to a diffusion furnace heated to a temperature of about 700 to about 760° C. for about 0.5 to about 4 minutes while continuously moving through a retort under a flowing hydrogen atmosphere. The steel fibers then emerge into air and are cooled for a sufficient time to bring them to room temperature. The diffusion furnacing allows the aluminum coating to partially diffuse into the plurality of steel fibers and form an aluminide layer. Without wishing to be bound by any theory, these partially diffused aluminide layers may contribute to corrosion resistance and adherence of the aluminum oxide outer layer formed during the oxidative furnacing step. [0106] The method of the present embodiment of the instant invention does not require a liquid bath leaching step after reductive furnacing (i.e., the diffusion furnacing step) is completed. Therefore, once the steel fiber mats have been cooled, they are subjected to forming steps followed by oxidative furnacing or subjected directly to oxidative furnacing prior to any forming. The steel fiber mats are typically oxidatively furnaced for approximately 5 to 15 minutes. In addition, the oxidative furnace operates under flowing air and is usually heated to a temperature of about 600° Celsius to about 950° Celsius. More typically, the oxidative furnace is heated to a maximum temperature of about 650° Celsius to about 850° Celsius. If the fiber mat is formed into a shaped body after diffusion furnacing and prior to oxidation furnacing, the fully shaped body (i.e., in finished form) is placed into a static furnace for oxidative treatment in air. [0107] The oxidative furnacing produces a substantially uniform aluminum oxide outer layer on the steel fibers by oxidizing the residual aluminum left on the surface of the plurality of steel fibers after diffusion furnacing. The resulting aluminum oxide outer layer interfaces with (and is strongly adhered to) the aluminide layer. The interaction between the aluminum oxide outer layer and aluminide layer provides high temperature stability to the fibrous material. FIGS. 4B and 4C show SEM images of one of the thin steel fibers of the instant disclosure after the aluminum oxide outer layer has been formed. [0108] In addition, the aluminum oxide outer layer is thick enough to act as a catalyst support with or without a washcoat layer. The thickness of this aluminum oxide outer layer can be controlled, by some degree, by adjusting the thickness of the initial aluminum coating, by the diffusion furnacing conditions, and by the degree of oxidation of the aluminum. Furthermore, the resulting surface area of the aluminum oxide outer layer can be controlled by adjusting the final calcination temperature or by adding stabilizing components (e.g., cerium oxide) in a small quantity, either to the coating slurry or introduced by impregnation as aqueous cerium salt solutions after the aluminum oxide coating is formed, followed by calcination. [0109] The catalytic soot trap embodiment of the present invention is further illustrated in the non-limiting examples described below. Example 9 [0110] A ¼ inch thick×2 inch wide coarse, medium, or fine grade 430 or 434 coiled stainless steel mat is fed into a continuous falling film coater (no Mayer rods) and the mat is coated with an aluminicious slurry comprising 62% solids (aluminum powder; about 10 micron average particle size) and 10% methylacrylate-type binder in acetone, wherein the slurry has been previously ball milled with steel shot overnight. Cerium oxide is optionally added at a dosage of about 2% of the anticipated aluminum oxide. The slurry is continuously stirred during the coating process. [0111] The coated steel fiber mat rises vertically at about six feet per minute to generate a substantially uniform coating by the falling film method. The web speed and vertical distance over which the falling film drops (i.e., the length of the zone before the dryer) can be optimized to adjust the thickness of the aluminicious slurry coating. After coating, the coated steel fiber mat moves vertically through a drying section to set the binder and then moves continuously through rubber pinch rollers to a retort under flowing hydrogen. The retort is housed in a clam-shell furnace that comprises a four-foot heated zone held at 730° Celsius. The steel fiber mat emerges into air and is cooled before traveling to an oxidative furnace operating under flowing air. Alternatively, the furnaced steel fiber mat can be fabricated into a soot trap form factor at this stage followed by oxidative furnacing of the fabricated part. The oxidative furnace is heated to about 800° Celsius to about 950° Celsius for continuous processing of a fiber mat. The steel fiber mat is exposed to the oxidative furnace for about 5 to about 15 minutes. A static furnace is used to oxidize pre-formed parts. [0112] The product (i.e., mat of fibers) that emerges from the oxidative furnace can be coiled and cut to a desired length for fabrication into a soot trap. Once oxidized and fabricated, the formed soot trap component can be impregnated with catalytic agents and calcined using methods known in the art. For example, a simple catalytic soot trap (suitable as a test prototype) can be produced by taking the fibrous material after it emerges from the oxidative furnace, coiling it, cutting the coiled material, folding the coiled and cut material upon itself, rolling the folded material into a cylindrical shape and then sliding that cylindrical body into a 0.86 inch ID stainless steel tube cut to a 3-inch length. An aqueous solution of a platinum group metal(s) may then be impregnated into the formed soot trap and the form calcined. [0113] In one aspect of the invention, the mat of thin steel fibers that emerges from the oxidative furnace is impregnated with a solution or suspension comprising a platinum group metal catalyst and then dried and, optionally, further heat treated to form the final catalytic fibrous material. [0114] As used herein, the term “platinum group metal catalyst” means any platinum group metal compound or complex, which, upon calcination or use of the catalyst decomposes or otherwise converts to a catalytically active form. Water soluble compounds or water dispersible complexes as well as organic soluble or dispersible compounds or complexes of one or more platinum group metals may be utilized as long as the liquid used to impregnate or deposit the catalytic metal compounds onto the plurality of thin coated steel fibers does not adversely react with the catalytic metal or its compound or complex or the other components of the catalytic material, and is capable of being removed from the catalyst by volatilization or decomposition upon heating. In some instances, the completion of the removal of the liquid may not take place until the catalyst is placed into use and subjected to the high temperatures encountered during operation. [0115] Typically, aqueous solutions of soluble compounds or complexes of the platinum group metals are preferred. For example, some of the compounds that may be used in the fibrous material of the instant disclosure include: gold (III) acetate, hydrogen tetrachloroaurate (III), ammonium hexachloroiridate (IV), iridium (III) chloride hydrate, ammonium tetrachloropalladate (II), palladium (II) nitrate, ammonium tetrachloroplatinate (II), dihydrogen hexachloroplatinate (IV) (chloroplatinic acid), tetraamineplatinum (II) nitrate, rhodium (III) chloride hydrate, potassium pentachlororhodate (III), rhodium nitrate, ruthenium (III) chloride, and pentaaminepyridineruthenium (II) tetrafluoborate. Additional compounds may be added as cocatalytic agents, promoters, or as modifiers along with the platinum group metal compounds. Separate impregnation steps may be necessary for certain added compounds that might react to form precipitates with the platinum group metal compounds. Examples of non-platinum group metal promoter/cocatalytic agent compounds include ammonium hexanitrocerrate (IV) and manganese (II) nitrate. [0116] Once impregnation of the product (i.e., mat of steel fibers) that emerges from the oxidative furnace with the solution or suspension comprising a platinum group metal catalyst is complete, the product is calcined to convert the platinum group metal of the platinum group metal catalyst to a well dispersed form, which is either catalytically active or transforms to an active form in use. [0117] After impregnation is complete, a filter may be formed from the fibrous material that is suitable for partial capture of soot particles from diesel engine exhaust. Some filter designs are known in the art for this purpose. These typically feature aspects such as partial bypass channels that enable approximately even distribution of captured particles throughout the depth of the filter element and serve to reduce pressure drop across the filter. After final treatment, fiber mats typically are compressed into relatively dense beds (of predefined densities) around the bypass structures, which can be corrugated metal spacers, tubular pipes, grooves in the housing, or similar features. The assembly then is fitted into a shroud of appropriate dimensions for attachment to engine exhaust manifolds. When in use, periodic or continuous catalytically initiated oxidation of embedded soot particles, under appropriate lean burn conditions, allows the filter element to destroy embedded soot and to reduce pressure drop caused by particulate buildup within the filter over time. [0118] In another aspect of the disclosure, a filter is formed from the product that emerges from the oxidative furnace in a similar fashion to that described above. The filter (as an individual part) is then impregnated with a solution or suspension comprising a platinum group metal catalyst and, optionally, a promoter or co-catalytic agent, then heat treated as is appropriate to convert the catalyst precursors to active forms. Example 10 Laboratory Preparation and Characterization of Catalyst Support Fibers [0119] Stainless steel grade 430 fibers of elliptical shape in the diameter range of approximately 125 to 220 micron were supplied by Ribbon Technology Corporation in the form of a loosely pressed mat. The mat was cut into eight inch strips approximately 3 inches wide, washed with acetone, and air dried. Each of several mat strips then were mounted into a laboratory-scale falling film dip coating machine and coated with a slurry composition consisting of 57.8% by weight aluminum metal powder (about 3 micron average particle size), 4.2% by weight methyl acrylate-based binder, and the balance acetone solvent. The coating slurry, prepared in a 900 mL batch, had been ball-milled overnight prior to coating using approximately 150 mL of ¼ inch diameter stainless steel balls as grinding/mixing media. After coating, each mat was hung vertically in a hot air stream to dry, then stapled or spot welded to a 2 mil thick low carbon steel foil leader. The composite assembly of leader and fiber mat was passed through a 4 foot furnace, which had been fitted with a steel retort, held at 710° C. under flowing hydrogen at a feed rate of 6 feet per minute. The furnaced mat was cooled in air and cut into various aliquots used for further work. In some cases, the furnaced, aluminized fibers first were formed into compressed cylinders suitable for filtration prior to further processing, and in other cases, the loosely pressed mats were oxidized directly, as described below, then formed. [0120] In a first oxidation stage, the furnaced material was heated in air in a static oven ramped at 10° C. per minute between room temperature and 620° C., then held at 620° C. for 1.5 hours. In a second stage, the oven temperature was increased from 620° C. to 850° C. at a ramp rate of 8° C./minute then soaked at 850° C. for 20 minutes. The sample was then cooled to room temperature in air slowly, and held within the oven as it cooled. Oxidized fibers increased in weight by about 1% during this treatment. Oxidized fibers were characterized by SEM, EDS, and TGA techniques and some aliquots tested as catalyst supports in the form of fiber mats. FIG. 4 shows Scanning Electron Microscope images of the aluminum coated and oxidized fibers of this example compared to untreated fibers, as received. FIG. 4A shows the untreated control fibers as received. FIG. 4B shows a low magnification image of treated fibers after the oxidation step. FIG. 4C shows a high magnification image of treated fibers after the oxidation step. Surface analysis by the EDS technique corresponding to one of the images of the treated and oxidized fibers shows an oxygen to aluminum atomic ratio of 1.5, consistent with a surface composition rich in aluminum oxide. [0121] The fiber mat catalyst supports produced above can be infiltrated with solutions or suspensions of catalyst materials (e.g., platinum group metal or “PGM” catalyst materials) and then dried to form catalytically active bodies. Alternatively, we contemplate that other methods known in the art may be suitable to load active catalytic species onto the support surfaces (e.g., chemical vapor deposition methods or supercritical precipitation methods). [0122] Still other objects and advantages of the present disclosure will become readily apparent to those skilled in the art from the preceding detailed description, wherein it is shown and described in preferred embodiments, simply by way of illustration of the best mode contemplated. As will be realized the disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, without departing from the spirit or scope of the invention as set forth in the claims. Accordingly, the description is to be regarded as illustrative in nature and not as restrictive. [0123] The term “comprising” (and its grammatical variations) as used herein is used in the inclusive sense of “having” or “including” and not in the exclusive sense of “consisting only of.” The term “consisting essentially of” as used herein is intended to refer to that which is explicitly recited along with what does not materially affect the basic and novel characteristics of that recited or specified. The terms “a” and “the” as used herein are understood to encompass the plural as well as the singular.

The present invention relates to methods for producing metal-supported thin layer skeletal catalyst structures, to methods for producing catalyst support structures without separately applying an intermediate washcoat layer, and to novel catalyst compositions produced by these methods. Catalyst precursors may be interdiffused with the underlying metal support then activated to create catalytically active skeletal alloy surfaces. The resulting metal-anchored skeletal layers provide increased conversion per geometric area compared to conversions from other types of supported alloy catalysts of similar bulk compositions, and provide resistance to activity loss when used under severe on-stream conditions. Particular compositions of the metal-supported skeletal catalyst alloy structures can be used for conventional steam methane reforming to produce syngas from natural gas and steam, for hydrodeoxygenation of pyrolysis bio-oils, and for other metal-catalyzed reactions inter alia.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to the field of liquid crystal displaying, and in particular to a gate-driver-on-array (GOA) circuit. [0003] 2. The Related Arts [0004] Liquid crystal displays (LCDs) have a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and are thus widely used. The development of the liquid crystal display industry brings in increasingly severer performance requirements, such as performance related to high resolution, high brightness, wide view angle, and low power consumption, and associated techniques have been developed. Most of the liquid crystal displays that are currently available in the market are backlighting liquid crystal displays, which comprise a liquid crystal display panel and a backlight module. The operation principle of the liquid crystal display panel is that, with liquid crystal molecules interposed between two parallel glass substrates, application of a drive voltage is selectively carried out by means of a driver circuit to the two glass substrates to control the liquid crystal molecules to change direction in order to refract out light emitting from the backlight module for generating images. [0005] The recent development of the LCDs is toward high integration and low cost of which an important technique is the realization of mass production of gate driver on array (GOA) technique. The GOA technique uses the front-stage array process of TFT-LCD (Thin-Film Transistor Liquid Crystal Display) to make a gate line scan drive signal circuit on an array substrate of a liquid crystal display panel in order to achieve progressive gate scanning. Using the GOA technique to integrate the gate line scan drive signal circuit on the array substrate of the liquid crystal display panel allows for omission of a gate driver integrated circuit so as to reduce the cost of product in both material cost and manufacturing operation. Such a gate line scan drive signal circuit that is integrated on an array substrate by means of the GOA technique is also referred to as a GOA circuit. The GOA circuit comprises a plurality of GOA units and as show in FIG. 1 , a circuit diagram of a GOA unit of a conventional GOA circuit is shown, comprising: a pull-up circuit 100 , a pull-up control circuit 200 , a pull-down circuit 300 , a first pull-down holding circuit 400 , and a second pull-down holding circuit 500 , wherein the pull-up circuit 100 functions to output a clock signal CKn as a gate signal G n . The pull-up control circuit 200 controls the activation time of the pull-up circuit 100 and is generally connected to a transfer signal ST n−1 transmitted from a previous stage GOA unit and the gate signal G n−1 thereof. The first pull-down holding circuit 400 pulls the gate line down to a low voltage at first time, namely shutting off the gate signal. The second pull-down holding circuit 500 functions to maintain the gate signal G n and a control signal Q n of the pull-up circuit 100 at a shut-off condition (namely a negative potential). The GOA circuit is commonly provided with two low level signal lines and the two low level signal lines respectively supply a first low level signal V ss1 and a second low level signal V ss2 , whereby the second low level V ss2 is used to reduce the voltage difference V gs between the gate terminal and the source terminal of the pull-up circuit 100 when the scan circuit is at a closed (holding) time so as to reduce the leakage currents of the pull-up circuit 100 and the second pull-down holding circuit 500 . A capacitor C boost provides secondary boost of the control signal Q n of the pull-up circuit 100 to facilitate the output of the gate signal G n . [0006] However, the conventional GOA circuit suffers the following two shortcomings: [0007] (1) A conductive path exists between two different negative potentials. Referring to FIG. 2 , which is an equivalent circuit diagram of FIG. 1 , L 100 indicates a loop of the leakage current induced by the connection of a thin-film transistor T 110 to the previous stage GOA unit and L 200 indicates a loop of the leakage current induced by the connection of a thin-film transistor T 410 to the instant stage GOA unit. The conventional GOA circuit would cause an effect of a great current between the leakage current loops L 100 and L 200 . The magnitude of the current is directly related to the potentials of pull-down points P n and K n . Further, the current conducted therethrough is proportional to the number of the stages of the GOA circuit. This leads to an increase of the loading of the signal sources of V ss1 and V ss2 and in the worst case, abnormality of image displaying may result. [0008] (2) The diode design of thin-film transistors T 510 and T 610 makes it is not possible for the high voltage of the pull-down points P n and K n to be quickly released and the voltage variations at the points of P n and K n are illustrated in FIG. 3 . This increases the influence of stress on four primary thin-film transistors T 320 , T 420 , T 330 , T 430 of the first and second pull-down holding circuits 400 , 500 , eventually affecting the operation service life of the GOA circuit. SUMMARY OF THE INVENTION [0009] An object of the present invention is to provide a GOA (Gate-Driver-on-Array) circuit, which uses a GOA technique to reduce the cost of a liquid crystal display and to overcome the problems of poor performance of the conventional the GOA circuit caused by introduction of two low level signals into the GOA circuit and short operation service life of the GOA circuit and enhance the quality of displayed images. [0010] To achieve the above object, the present invention provides a GOA circuit, which comprises multiple stages of GOA units connected in cascade, wherein: [0011] for each nth stage GOA unit between the second stage and the last second stage of the GOA circuit, the nth stage GOA unit comprises a first (n−1)th stage signal input terminal, a second (n−1)th stage signal input terminal, a (n+1)th stage signal input terminal, a first output terminal, and a second output terminal, wherein the first output terminal of the nth stage GOA unit is provided for driving an active zone of an array substrate; the first (n−1)th stage signal input terminal, the second (n−1)th stage signal input terminal, and the (n+1)th stage signal input terminal of the nth stage GOA unit are respectively and electrically connected to the first output terminal and the second output terminal of the (n−1)th GOA unit and the first output terminal of the (n+1)th GOA unit, the first output terminal of the nth stage GOA unit being electrically connected to the first (n−1)th stage signal input terminal of the (n+1)th GOA unit and the (n+1)th stage signal input terminal of the (n−1)th GOA unit, the second output terminal of the nth stage GOA unit being electrically connected to the second (n−1)th stage signal input terminal of the (n+1)th GOA unit; [0012] for the nth stage GOA unit at the first stage of the GOA circuit, the nth stage GOA unit comprises a first (n−1)th stage signal input terminal, a second (n−1)th stage signal input terminal, a (n+1)th stage signal input terminal, a first output terminal, and a second output terminal, wherein the first output terminal of the nth stage GOA unit is provided for driving an active zone of an array substrate; the first (n−1)th stage signal input terminal and the second (n−1)th stage signal input terminal of the nth stage GOA unit both provided for receiving an input of a pulse activation signal and the (n+1)th stage signal input terminal is electrically connected to the first output terminal of the (n+1)th GOA unit, the first output terminal and the second output terminal of the nth stage GOA unit being respectively and electrically connected to the first (n−1)th stage signal input terminal and the second (n−1)th stage signal input terminal of the (n+1)th GOA unit; [0013] for the nth stage GOA unit at the last stage of the GOA circuit, the nth stage GOA unit comprises a first (n−1)th stage signal input terminal, a second (n−1)th stage signal input terminal, a (n+1)th stage signal input terminal, a first output terminal, and a second output terminal; the first (n−1)th stage signal input terminal and the second input terminal of the nth stage GOA unit are respectively and electrically connected to the first output terminal and the second output terminal of the (n−1)th GOA unit, the (n+1)th stage signal input terminal of the nth stage GOA unit being provided to receive an input of a pulse activation signal, the first output terminal of the nth stage GOA unit being electrically connected to the (n+1)th stage signal input terminal of the (n−1)th GOA unit and the second output terminal being open; [0014] for each nth stage GOA unit between the first stage and the last stage of the GOA circuit, the nth stage GOA unit further comprises a first clock signal input terminal, a first low level input terminal, and a second low level input terminal, the first low level input terminal being provided for receiving an input of a first low level, the second low level input terminal being provided for receiving an input of a second low level, the second low level being smaller than the first low level; [0015] for each nth stage GOA unit between the first stage and the last stage of the GOA circuit, the nth stage GOA unit further comprises: [0016] a pull-up control unit, which is electrically connected to the first (n−1)th stage signal input terminal and the second (n−1)th stage signal input terminal; [0017] a pull-up unit, which is electrically connected to the pull-up control unit and the first clock signal input terminal, the first output terminal, and the second output terminal; [0018] a first pull-down holding unit, which is electrically connected to the first low level input terminal, the second low level input terminal, the pull-up control unit, and the pull-up unit; [0019] a second pull-down holding unit, which is electrically connected to the first low level input terminal, the second low level input terminal, the first pull-down holding unit, the pull-up control unit, and the pull-up unit; and [0020] a pull-down unit, which is electrically connected to the (n+1)th stage signal input terminal, the first low level input terminal, the pull-up control unit, the pull-up unit, the first pull-down holding unit, the second pull-down holding unit, and the first output terminal. [0021] The first clock signal input terminal has an input signal that is a first clock signal or a second clock signal, the first clock signal being opposite in phase to the second clock signal; when the input signal of the first clock signal input terminal of the nth stage GOA unit of the GOA circuit is the first clock signal, the input signal of the first clock signal input terminal of the (n+1)th stage GOA unit of the GOA circuit is the second clock signal. [0022] The pull-up control unit is a first thin-film transistor and the first thin-film transistor comprises a first gate terminal, a first source terminal, and a first drain terminal, wherein the first gate terminal is electrically connected to the second (n−1)th stage signal input terminal; the first source terminal is electrically connected to the first (n−1)th stage signal input terminal; and the first drain terminal is electrically connected to the first and second pull-down holding units, the pull-down unit, and the pull-up unit. [0023] The pull-up unit comprises a capacitor, a second thin-film transistor, and a third thin-film transistor and the second thin-film transistor comprises a second gate terminal, a second source terminal, and a second drain terminal and the third thin-film transistor comprises a third gate terminal, a third source terminal, and a third drain terminal, wherein the second gate terminal is electrically connected to one end of the capacitor, the first drain terminal, the third gate terminal, the first and second pull-down holding units, and the pull-down unit; the second source terminal is electrically connected to the third source terminal and the first clock signal input terminal; the second drain terminal is electrically connected to the second output terminal; and the third drain terminal is electrically connected to the first output terminal, the first and second pull-down holding units, the pull-down unit, and an opposite end of the capacitor. [0024] The pull-down unit comprises fourth and fifth thin-film transistors and the fourth thin-film transistor comprises a fourth gate terminal, a fourth source terminal, and a fourth drain terminal and the fifth thin-film transistor comprises a fifth gate terminal, a fifth source terminal, and a fifth drain terminal, wherein the fourth gate terminal is electrically connected to the fifth gate terminal and the (n+1)th stage signal input terminal; the fourth source terminal is electrically connected to a first low level input terminal and the fifth source terminal; the fourth drain terminal is electrically connected to the first drain terminal, said one end of the capacitor, the second gate terminal, the third gate terminal, and the first and second pull-down holding units; and the fifth drain terminal is electrically connected to the first output terminal, the third source terminal, said opposite end of the capacitor, and the first and second pull-down holding units. [0025] The first pull-down holding unit comprises sixth to ninth thin-film transistors and the sixth thin-film transistor comprises a sixth gate terminal, a sixth source terminal, and a sixth drain terminal; the seventh thin-film transistor comprises a seventh gate terminal, a seventh source terminal, and a seventh drain terminal; the eighth thin-film transistor comprises an eighth gate terminal, an eighth source terminal, and an eighth drain terminal; and the ninth thin-film transistor comprises a ninth gate terminal, a ninth source terminal, and a ninth drain terminal, wherein the sixth drain terminal is electrically connected to the seventh drain terminal, the eighth gate terminal, and the ninth gate terminal; the seventh gate terminal is electrically connected to the first drain terminal, the ninth drain terminal, said one end of the capacitor, the second gate terminal, the third gate terminal, the fourth drain terminal, and the second pull-down holding unit; the seventh source terminal is electrically connected to a second low level input terminal; the eighth drain terminal is electrically connected to said opposite end of the capacitor, the second pull-down holding unit, and the first output terminal; the eighth source terminal is electrically connected to the first low level input terminal; and the ninth source terminal is electrically connected to the first low level input terminal; and [0026] the second pull-down holding unit comprises tenth to thirteenth thin-film transistors and the tenth thin-film transistor comprises a tenth gate terminal, a tenth source terminal, and a tenth drain terminal; the eleventh thin-film transistor comprises an eleventh gate terminal, an eleventh source terminal, and an eleventh drain terminal; the twelfth thin-film transistor comprises a twelfth gate terminal, a twelfth source terminal, and a twelfth drain terminal; and the thirteenth thin-film transistor comprises a thirteenth gate terminal, a thirteenth source terminal, and a thirteenth drain terminal, wherein the tenth drain terminal is electrically connected to the eleventh drain terminal, the twelfth gate terminal, and the thirteenth gate terminal; the eleventh gate terminal is electrically connected to the first drain terminal, the thirteenth drain terminal, the seventh gate terminal, the ninth drain terminal, and said one end of the capacitor; the eleventh source terminal is electrically connected to the second low level input terminal; the twelfth drain terminal is electrically connected to said opposite end of the capacitor, the eighth drain terminal, and the first output terminal; the twelfth source terminal is electrically connected to the first low level input terminal; and the thirteenth source terminal is electrically connected to the first low level input terminal. [0027] The nth stage GOA unit of the GOA circuit further comprises a second clock signal input terminal and a third clock signal input terminal, the sixth gate terminal and the sixth source terminal being connected to the second clock signal input terminal, the tenth gate terminal and the tenth source terminal being connected to the third clock signal input terminal, the second clock signal input terminal receiving an input of the first clock signal, the third clock signal input terminal receiving an input of the second clock signal. [0028] The first pull-down holding unit further comprises a fourteenth thin-film transistor and the fourteenth thin-film transistor comprises a fourteenth gate terminal, a fourteenth source terminal, and a fourteenth drain terminal, wherein the fourteenth drain terminal is electrically connected to the sixth drain terminal, the seventh drain terminal, the eighth gate terminal, and the ninth gate terminal; and the fourteenth source terminal is electrically connected to the sixth gate terminal, the sixth source terminal, and the second clock signal input terminal; and the second pull-down holding unit further comprises a fifteenth thin-film transistor and the fifteenth thin-film transistor comprises a fifteenth gate terminal, a fifteenth source terminal, and a fifteenth drain terminal, wherein the fifteenth drain terminal is electrically connected to the tenth drain terminal, the eleventh drain terminal, the twelfth gate terminal, and the thirteenth gate terminal and the fifteenth source terminal is electrically connected to the tenth gate terminal and the tenth source terminal. [0029] The nth stage GOA unit of the GOA circuit further comprises a second clock signal input terminal and a third clock signal input terminal; the sixth gate terminal, the sixth source terminal, and the fourteenth source terminal are connected to the second clock signal input terminal; the fourteenth gate terminal is connected to the third clock signal input terminal; the tenth gate terminal, the tenth source terminal, and the fifteenth source terminal are connected to the third clock signal input terminal; the fifteenth gate terminal is connected to the second clock signal input terminal; and the second clock signal input terminal receives an input of the first clock signal and the third clock signal input terminal receives an input of the second clock signal. [0030] The nth stage GOA unit of the GOA circuit further comprises a first low frequency signal input terminal and a second low frequency input terminal, the sixth gate terminal; the sixth source terminal and the fourteenth source terminal are connected to the first low frequency signal input terminal; the fourteenth gate terminal is connected to the second low frequency signal input terminal; the tenth gate terminal, the tenth source terminal, and the fifteenth source terminal are connected to the second low frequency signal input terminal; the fifteenth gate terminal is connected to the first low frequency signal input terminal; and the first low frequency signal input terminal receives an input of a low frequency signal or an ultralow frequency signal and the second low frequency signal input terminal receives an input of a low frequency signal or an ultralow frequency signal. [0031] The present invention further provides a GOA circuit, comprising multiple stages of GOA units connected in cascade, wherein: [0032] for each nth stage GOA unit between the second stage and the last second stage of the GOA circuit, the nth stage GOA unit comprises a first (n−1)th stage signal input terminal, a second (n−1)th stage signal input terminal, a (n+1)th stage signal input terminal, a first output terminal, and a second output terminal, wherein the first output terminal of the nth stage GOA unit is provided for driving an active zone of an array substrate; the first (n−1)th stage signal input terminal, the second (n−1)th stage signal input terminal, and the (n+1)th stage signal input terminal of the nth stage GOA unit are respectively and electrically connected to the first output terminal and the second output terminal of the (n−1)th GOA unit and the first output terminal of the (n+1)th GOA unit, the first output terminal of the nth stage GOA unit being electrically connected to the first (n−1)th stage signal input terminal of the (n+1)th GOA unit and the (n+1)th stage signal input terminal of the (n−1)th GOA unit, the second output terminal of the nth stage GOA unit being electrically connected to the second (n−1)th stage signal input terminal of the (n+1)th GOA unit; [0033] for the nth stage GOA unit at the first stage of the GOA circuit, the nth stage GOA unit comprises a first (n−1)th stage signal input terminal, a second (n−1)th stage signal input terminal, a (n+1)th stage signal input terminal, a first output terminal, and a second output terminal, wherein the first output terminal of the nth stage GOA unit is provided for driving an active zone of an array substrate; the first (n−1)th stage signal input terminal and the second (n−1)th stage signal input terminal of the nth stage GOA unit both provided for receiving an input of a pulse activation signal and the (n+1)th stage signal input terminal is electrically connected to the first output terminal of the (n+1)th GOA unit, the first output terminal and the second output terminal of the nth stage GOA unit being respectively and electrically connected to the first (n−1)th stage signal input terminal and the second (n−1)th stage signal input terminal of the (n+1)th GOA unit; [0034] for the nth stage GOA unit at the last stage of the GOA circuit, the nth stage GOA unit comprises a first (n−1)th stage signal input terminal, a second (n−1)th stage signal input terminal, a (n+1)th stage signal input terminal, a first output terminal, and a second output terminal; the first (n−1)th stage signal input terminal and the second input terminal of the nth stage GOA unit are respectively and electrically connected to the first output terminal and the second output terminal of the (n−1)th GOA unit, the (n+1)th stage signal input terminal of the nth stage GOA unit being provided to receive an input of a pulse activation signal, the first output terminal of the nth stage GOA unit being electrically connected to the (n+1)th stage signal input terminal of the (n−1)th GOA unit and the second output terminal being open; [0035] for each nth stage GOA unit between the first stage and the last stage of the GOA circuit, the nth stage GOA unit further comprises a first clock signal input terminal, a first low level input terminal, and a second low level input terminal, the first low level input terminal being provided for receiving an input of a first low level, the second low level input terminal being provided for receiving an input of a second low level, the second low level being smaller than the first low level; [0036] for each nth stage GOA unit between the first stage and the last stage of the GOA circuit, the nth stage GOA unit further comprises: [0037] a pull-up control unit, which is electrically connected to the first (n−1)th stage signal input terminal and the second (n−1)th stage signal input terminal; [0038] a pull-up unit, which is electrically connected to the pull-up control unit and the first clock signal input terminal, the first output terminal, and the second output terminal; [0039] a first pull-down holding unit, which is electrically connected to the first low level input terminal, the second low level input terminal, the pull-up control unit, and the pull-up unit; [0040] a second pull-down holding unit, which is electrically connected to the first low level input terminal, the second low level input terminal, the first pull-down holding unit, the pull-up control unit, and the pull-up unit; and [0041] a pull-down unit, which is electrically connected to the (n+1)th stage signal input terminal, the first low level input terminal, the pull-up control unit, the pull-up unit, the first pull-down holding unit, the second pull-down holding unit, and the first output terminal; [0042] wherein the first clock signal input terminal has an input signal that is a first clock signal or a second clock signal, the first clock signal being opposite in phase to the second clock signal; when the input signal of the first clock signal input terminal of the nth stage GOA unit of the GOA circuit is the first clock signal, the input signal of the first clock signal input terminal of the (n+1)th stage GOA unit of the GOA circuit is the second clock signal; [0043] wherein the pull-up control unit is a first thin-film transistor and the first thin-film transistor comprises a first gate terminal, a first source terminal, and a first drain terminal, wherein the first gate terminal is electrically connected to the second (n−1)th stage signal input terminal; the first source terminal is electrically connected to the first (n−1)th stage signal input terminal; and the first drain terminal is electrically connected to the first and second pull-down holding units, the pull-down unit, and the pull-up unit; [0044] wherein the pull-up unit comprises a capacitor, a second thin-film transistor, and a third thin-film transistor and the second thin-film transistor comprises a second gate terminal, a second source terminal, and a second drain terminal and the third thin-film transistor comprises a third gate terminal, a third source terminal, and a third drain terminal, wherein the second gate terminal is electrically connected to one end of the capacitor, the first drain terminal, the third gate terminal, the first and second pull-down holding units, and the pull-down unit; the second source terminal is electrically connected to the third source terminal and the first clock signal input terminal; the second drain terminal is electrically connected to the second output terminal; and the third drain terminal is electrically connected to the first output terminal, the first and second pull-down holding units, the pull-down unit, and an opposite end of the capacitor; [0045] wherein the pull-down unit comprises fourth and fifth thin-film transistors and the fourth thin-film transistor comprises a fourth gate terminal, a fourth source terminal, and a fourth drain terminal and the fifth thin-film transistor comprises a fifth gate terminal, a fifth source terminal, and a fifth drain terminal, wherein the fourth gate terminal is electrically connected to the fifth gate terminal and the (n+1)th stage signal input terminal; the fourth source terminal is electrically connected to a first low level input terminal and the fifth source terminal; the fourth drain terminal is electrically connected to the first drain terminal, said one end of the capacitor, the second gate terminal, the third gate terminal, and the first and second pull-down holding units; and the fifth drain terminal is electrically connected to the first output terminal, the third source terminal, said opposite end of the capacitor, and the first and second pull-down holding units; and [0046] wherein the first pull-down holding unit comprises sixth to ninth thin-film transistors and the sixth thin-film transistor comprises a sixth gate terminal, a sixth source terminal, and a sixth drain terminal; the seventh thin-film transistor comprises a seventh gate terminal, a seventh source terminal, and a seventh drain terminal; the eighth thin-film transistor comprises an eighth gate terminal, an eighth source terminal, and an eighth drain terminal; and the ninth thin-film transistor comprises a ninth gate terminal, a ninth source terminal, and a ninth drain terminal, wherein the sixth drain terminal is electrically connected to the seventh drain terminal, the eighth gate terminal, and the ninth gate terminal; the seventh gate terminal is electrically connected to the first drain terminal, the ninth drain terminal, said one end of the capacitor, the second gate terminal, the third gate terminal, the fourth drain terminal, and the second pull-down holding unit; the seventh source terminal is electrically connected to a second low level input terminal; the eighth drain terminal is electrically connected to said opposite end of the capacitor, the second pull-down holding unit, and the first output terminal; the eighth source terminal is electrically connected to the first low level input terminal; and the ninth source terminal is electrically connected to the first low level input terminal; and [0047] the second pull-down holding unit comprises tenth to thirteenth thin-film transistors and the tenth thin-film transistor comprises a tenth gate terminal, a tenth source terminal, and a tenth drain terminal; the eleventh thin-film transistor comprises an eleventh gate terminal, an eleventh source terminal, and an eleventh drain terminal; the twelfth thin-film transistor comprises a twelfth gate terminal, a twelfth source terminal, and a twelfth drain terminal; and the thirteenth thin-film transistor comprises a thirteenth gate terminal, a thirteenth source terminal, and a thirteenth drain terminal, wherein the tenth drain terminal is electrically connected to the eleventh drain terminal, the twelfth gate terminal, and the thirteenth gate terminal; the eleventh gate terminal is electrically connected to the first drain terminal, the thirteenth drain terminal, the seventh gate terminal, the ninth drain terminal, and said one end of the capacitor; the eleventh source terminal is electrically connected to the second low level input terminal; the twelfth drain terminal is electrically connected to said opposite end of the capacitor, the eighth drain terminal, and the first output terminal; the twelfth source terminal is electrically connected to the first low level input terminal; and the thirteenth source terminal is electrically connected to the first low level input terminal. [0048] The nth stage GOA unit of the GOA circuit further comprises a second clock signal input terminal and a third clock signal input terminal, the sixth gate terminal and the sixth source terminal being connected to the second clock signal input terminal, the tenth gate terminal and the tenth source terminal being connected to the third clock signal input terminal, the second clock signal input terminal receiving an input of the first clock signal, the third clock signal input terminal receiving an input of the second clock signal. [0049] The first pull-down holding unit further comprises a fourteenth thin-film transistor and the fourteenth thin-film transistor comprises a fourteenth gate terminal, a fourteenth source terminal, and a fourteenth drain terminal, wherein the fourteenth drain terminal is electrically connected to the sixth drain terminal, the seventh drain terminal, the eighth gate terminal, and the ninth gate terminal; and the fourteenth source terminal is electrically connected to the sixth gate terminal, the sixth source terminal, and the second clock signal input terminal; and the second pull-down holding unit further comprises a fifteenth thin-film transistor and the fifteenth thin-film transistor comprises a fifteenth gate terminal, a fifteenth source terminal, and a fifteenth drain terminal, wherein the fifteenth drain terminal is electrically connected to the tenth drain terminal, the eleventh drain terminal, the twelfth gate terminal, and the thirteenth gate terminal and the fifteenth source terminal is electrically connected to the tenth gate terminal and the tenth source terminal. [0050] The nth stage GOA unit of the GOA circuit further comprises a second clock signal input terminal and a third clock signal input terminal; the sixth gate terminal, the sixth source terminal, and the fourteenth source terminal are connected to the second clock signal input terminal; the fourteenth gate terminal is connected to the third clock signal input terminal; the tenth gate terminal, the tenth source terminal, and the fifteenth source terminal are connected to the third clock signal input terminal; the fifteenth gate terminal is connected to the second clock signal input terminal; and the second clock signal input terminal receives an input of the first clock signal and the third clock signal input terminal receives an input of the second clock signal. [0051] The nth stage GOA unit of the GOA circuit further comprises a first low frequency signal input terminal and a second low frequency input terminal, the sixth gate terminal; the sixth source terminal and the fourteenth source terminal are connected to the first low frequency signal input terminal; the fourteenth gate terminal is connected to the second low frequency signal input terminal; the tenth gate terminal, the tenth source terminal, and the fifteenth source terminal are connected to the second low frequency signal input terminal; the fifteenth gate terminal is connected to the first low frequency signal input terminal; and the first low frequency signal input terminal receives an input of a low frequency signal or an ultralow frequency signal and the second low frequency signal input terminal receives an input of a low frequency signal or an ultralow frequency signal. [0052] The efficacy of the present invention is that the present invention provides a GOA circuit, which uses two low level signals to reduce the leakage currents of the thin-film transistors of a pull-down holding unit, wherein the second low level that has a lower level provides a low voltage to pull-down points P n and K n and the first low level that has a higher level provides a low voltage to the pull-down points Q n and G n , so as to reduce the potentials of the pull-down point P n and K n when the pull-down point Q n and G n are activated to thereby facilitate charging of Q n and G n and also to break the leakage current loop of the circuit between two low level signals to greatly reduce the leakage current between the two low level signal, enhance the performance of the GOA circuit, and improve the quality of displayed images; further, the fourteenth thin-film transistor and the fifteenth thin-film transistor are additionally included in respect of the diode design of the sixth thin-film transistor and the tenth thin-film transistor to perform discharging to the pull-down points P n and K n , thereby achieving the potentials of P n and K n changing up and down with the variation of the first clock signal CK 1 and the second clock signal CK 2 , providing alternating operations so as to reduce the influence of the eighth and ninth thin-film transistor and the twelfth and thirteenth thin-film transistor by stresses, extending the lifespan of the GOA circuit. Further, using low frequency or ultralow frequency signals to control the pull-down holding unit effectively reduces power consumption of the circuit. [0053] For better understanding of the features and technical contents of the present invention, reference will be made to the following detailed description of the present invention and the attached drawings. However, the drawings are provided for the purposes of reference and illustration and are not intended to impose limitations to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS [0054] The technical solution, as well as other beneficial advantages, of the present invention will be apparent from the following detailed description of embodiments of the present invention, with reference to the attached drawing. In the drawing: [0055] FIG. 1 is a circuit diagram of a conventional GOA (Gate Driver on Array) circuit; [0056] FIG. 2 is an equivalent circuit of FIG. 1 ; [0057] FIG. 3 is a drive timing diagram of the GOA circuit shown in FIG. 1 ; [0058] FIG. 4 is a circuit diagram of a GOA circuit according to a preferred embodiment of the present invention; [0059] FIG. 5 is a drive timing diagram of the GOA circuit shown in FIG. 4 ; [0060] FIG. 6 is plot of a characteristic I-V curve of a thin-film transistor; [0061] FIG. 7 is a circuit diagram of a GOA circuit according to another preferred embodiment of the present invention; [0062] FIG. 8 is a drive timing diagram of the GOA circuit shown in FIG. 7 [0063] FIG. 9 is a circuit diagram of a GOA circuit according to a further preferred embodiment of the present invention; and [0064] FIG. 10 is a drive timing diagram of the GOA circuit shown in FIG. 9 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0065] To further expound the technical solution adopted in the present invention and the advantages thereof, a detailed description is given to a preferred embodiment of the present invention and the attached drawings. [0066] Referring to FIGS. 4-6 , the present invention provides a GOA (Gate-Driver-on-Array) circuit, which comprises multiple stages of GOA units connected in cascade, wherein: [0067] for each nth stage GOA unit between the second stage and the last second stage of the GOA circuit, the nth stage GOA unit comprises a first (n−1)th stage signal input terminal 21 (G n−1 ), a second (n−1)th stage signal input terminal 22 (ST n−1 ), a (n+1)th stage signal input terminal 23 (G n+1 ), a first output terminal 27 (G n ), and a second output terminal 28 (ST n ), wherein the first output terminal 27 (G n ) of the nth stage GOA unit is provided for driving an active zone of an array substrate; the first (n−1)th stage signal input terminal 21 (G n−1 ), the second (n−1)th stage signal input terminal 22 (ST n−1 ), and the (n+1)th stage signal input terminal 23 (G n+1 ) of the nth stage GOA unit are respectively and electrically connected to the first output terminal 27 (G n ) and the second output terminal 28 (ST n ) of the (n−1)th GOA unit and the first output terminal 27 (G n ) of the (n+1)th GOA unit, the first output terminal 27 (G n ) of the nth stage GOA unit being electrically connected to the first (n−1)th stage signal input terminal 21 (G n−1 ) of the (n+1)th GOA unit and the (n+1)th stage signal input terminal 23 (G n+1 ) of the (n−1)th GOA unit, the second output terminal 28 (ST n ) of the nth stage GOA unit being electrically connected to the second (n−1)th stage signal input terminal 22 (ST n−1 ) of the (n+1)th GOA unit; [0068] for the nth stage GOA unit at the first stage of the GOA circuit, the nth stage GOA unit comprises a first (n−1)th stage signal input terminal 21 (G n−1 ), a second (n−1)th stage signal input terminal 22 (ST n−1 ), a (n+1)th stage signal input terminal 23 (G n+1 ), a first output terminal 27 (G n ), and a second output terminal 28 (ST n ), wherein the first output terminal 27 (G n ) of the nth stage GOA unit is provided for driving an active zone of an array substrate; the first (n−1)th stage signal input terminal 21 (G n−1 ) and the second (n−1)th stage signal input terminal 22 (ST n−1 ) of the nth stage GOA unit both provided for receiving an input of a pulse activation signal and the (n+1)th stage signal input terminal 23 (G n+1 ) is electrically connected to the first output terminal 27 (G n ) of the (n+1)th GOA unit, the first output terminal 27 (G n ) and the second output terminal 28 (ST n ) of the nth stage GOA unit being respectively and electrically connected to the first (n−1)th stage signal input terminal 21 (G n−1 ) and the second (n−1)th stage signal input terminal 22 (ST n−1 ) of the (n+1)th GOA unit; [0069] for the nth stage GOA unit at the last stage of the GOA circuit, the nth stage GOA unit comprises a first (n−1)th stage signal input terminal 21 (G n−1 ), a second (n−1)th stage signal input terminal 22 (ST n−1 ), a (n+1)th stage signal input terminal 23 (G n+1 ), a first output terminal 27 (G n ), and a second output terminal 28 (ST n ); the first (n−1)th stage signal input terminal 21 (G n−1 ) and the second input terminal 22 (ST n−1 ) of the nth stage GOA unit are respectively and electrically connected to the first output terminal 27 (G n ) and the second output terminal 28 (ST n ) of the (n−1)th GOA unit, the (n+1)th stage signal input terminal 23 (G n+1 ) of the nth stage GOA unit being provided to receive an input of a pulse activation signal, the first output terminal 27 (G n ) of the nth stage GOA unit being electrically connected to the (n+1)th stage signal input terminal 23 (G n+1 ) of the (n−1)th GOA unit and the second output terminal 28 (ST n ) being open; [0070] for each nth stage GOA unit between the first stage and the last stage of the GOA circuit, the nth stage GOA unit further comprises a first clock signal input terminal 24 , a first low level input terminal 25 , and a second low level input terminal 26 , the first low level input terminal 25 being provided for receiving an input of a first low level V ss1 , the second low level input terminal 26 being provided for receiving an input of a second low level V ss2 , the second low level V ss2 being smaller than the first low level V ss1 ; [0071] for each nth stage GOA unit between the first stage and the last stage of the GOA circuit, the nth stage GOA unit further comprises: [0072] a pull-up control unit 42 , which is electrically connected to the first (n−1)th stage signal input terminal 21 and the second (n−1)th stage signal input terminal 22 ; [0073] a pull-up unit 44 , which is electrically connected to the pull-up control unit 42 and the first clock signal input terminal 24 , the first output terminal 27 , and the second output terminal 28 ; [0074] a first pull-down holding unit 46 , which is electrically connected to the first low level input terminal 25 , the second low level input terminal 26 , the pull-up control unit 42 , and the pull-up unit 44 ; [0075] a second pull-down holding unit 47 , which is electrically connected to the first low level input terminal 25 , the second low level input terminal 26 , the first pull-down holding unit 46 , the pull-up control unit 42 , and the pull-up unit 44 ; and [0076] a pull-down unit 48 , which is electrically connected to the (n+1)th stage signal input terminal 23 , the first low level input terminal 25 , the pull-up control unit 42 , the pull-up unit 44 , the first pull-down holding unit 46 , the second pull-down holding unit 47 , and the first output terminal 27 . [0077] In the instant embodiment, the nth stage GOA unit of the GOA circuit further comprises a second clock signal input terminal 31 and a third clock signal input terminal 32 . The first clock signal input terminal 24 has an input signal that is a first clock signal CK 1 or a second clock signal CK 2 , the second clock signal input terminal 31 having an input signal that is the first clock signal CK 1 , the third clock signal input terminal 32 having an input signal that is the second clock signal CK 2 , the first clock signal CK 1 being opposite in phase to the second clock signal CK 2 , meaning high and low voltages of the signals CK 1 and CK 2 being opposite to each other at a given time point; when the input signal of the first clock signal input terminal 24 of the nth stage GOA unit of the GOA circuit is the first clock signal CK 1 , the input signal of the first clock signal input terminal 24 of the (n+1)th stage GOA unit of the GOA circuit is the second clock signal CK 2 . [0078] The pull-up control unit 42 is a first thin-film transistor T 1 and the first thin-film transistor T 1 comprises a first gate terminal g 1 , a first source terminal s 1 , and a first drain terminal d 1 , wherein the first gate terminal g 1 is electrically connected to the second (n−1)th stage signal input terminal 22 ; the first source terminal s 1 is electrically connected to the first (n−1)th stage signal input terminal 21 ; and the first drain terminal d 1 is electrically connected to the first and second pull-down holding units 46 , 47 , the pull-down unit 48 , and the pull-up unit 44 . [0079] The pull-up unit 44 comprises a capacitor C b , a second thin-film transistor T 2 , and a third thin-film transistor T 3 and the second thin-film transistor T 2 comprises a second gate terminal g 2 , a second source terminal s 2 , and a second drain terminal d 2 and the third thin-film transistor T 3 comprises a third gate terminal g 3 , a third source terminal s 3 , and a third drain terminal d 3 , wherein the second gate terminal g 2 is electrically connected to one end of the capacitor C b , the first drain terminal d 1 , the third gate terminal g 3 , the first and second pull-down holding units 46 , 47 , and the pull-down unit 48 ; the second source terminal s 2 is electrically connected to the third source terminal s 3 and the first clock signal input terminal 24 ; the second drain terminal d 2 is electrically connected to the second output terminal 28 ; and the third drain terminal d 3 is electrically connected to the first output terminal 27 , the first and second pull-down holding units 46 , 47 , the pull-down unit 48 , and an opposite end of the capacitor C b . [0080] The pull-down unit 48 comprises fourth and fifth thin-film transistors T 4 , T 5 and the fourth thin-film transistor T 4 comprises a fourth gate terminal g 4 , a fourth source terminal s 4 , and a fourth drain terminal d 4 and the fifth thin-film transistor T 5 comprises a fifth gate terminal g 5 , a fifth source terminal s 5 , and a fifth drain terminal d 5 , wherein the fourth gate terminal g 4 is electrically connected to the fifth gate terminal g 5 and the (n+1)th stage signal input terminal 23 ; the fourth source terminal s 4 is electrically connected to a first low level input terminal and the fifth source terminal s 5 ; the fourth drain terminal d 4 is electrically connected to the first drain terminal d 1 , said one end of the capacitor C b , the second gate terminal g 2 , the third gate terminal g 3 , and the first and second pull-down holding units 46 , 47 ; and the fifth drain terminal d 5 is electrically connected to the first output terminal 27 , the third source terminal s 3 , said opposite end of the capacitor C b , and the first and second pull-down holding units 46 , 47 . [0081] The first pull-down holding unit 46 comprises sixth to ninth thin-film transistors T 6 , T 7 , T 8 , T 9 and the sixth thin-film transistor T 6 comprises a sixth gate terminal g 6 , a sixth source terminal s 6 , and a sixth drain terminal d 6 ; the seventh thin-film transistor T 7 comprises a seventh gate terminal g 7 , a seventh source terminal s 7 , and a seventh drain terminal d 7 ; the eighth thin-film transistor comprises an eighth gate terminal g 8 , an eighth source terminal s 8 , and an eighth drain terminal d 8 ; and the ninth thin-film transistor comprises a ninth gate terminal g 9 , a ninth source terminal s 9 , and a ninth drain terminal d 9 , wherein the sixth gate terminal g 6 and the sixth source terminal s 6 are connected to the second clock signal input terminal 31 ; the sixth drain terminal d 6 is electrically connected to a pull-down point P n , the seventh drain terminal d 7 , the eighth gate terminal g 8 , and the ninth gate terminal g 9 ; the seventh gate terminal g 7 is electrically connected to the first drain terminal d 1 , the ninth drain terminal d 9 , said one end of the capacitor C b , the second gate terminal g 2 , the third gate terminal g 3 , the fourth drain terminal d 4 , and the second pull-down holding unit 47 ; the seventh source terminal s 7 is electrically connected to a second low level input terminal 26 ; the eighth drain terminal d 8 is electrically connected to said opposite end of the capacitor C b , the second pull-down holding unit 47 , and the first output terminal 27 (G n ); the eighth source terminal s 8 is electrically connected to the first low level input terminal 25 ; and the ninth source terminal s 9 is electrically connected to the first low level input terminal 25 . [0082] The eighth thin-film transistor T 8 is provided generally for maintaining a low voltage of the first output terminal 27 (G n ); the ninth thin-film transistor T 9 is provided for maintaining a low voltage of the pull-down point Q n ; the seventh thin-film transistor T 7 is provided for setting pull-down points P n and K n at low voltages when Q n is at a high voltage and also for deactivating the first pull-down holding unit 46 to prevent the pull-down point Q n from affecting the first output terminal 27 (G n ). The second low level V ss2 being smaller than the first low level V ss1 helps reduce leakage currents of the eighth and ninth thin-film transistors T 8 , T 9 . [0083] The second pull-down holding unit 47 comprises tenth to thirteenth thin-film transistors T 10 , T 11 , T 12 , T 13 and the tenth thin-film transistor T 10 comprises a tenth gate terminal g 10 , a tenth source terminal s 10 , and a tenth drain terminal d 10 ; the eleventh thin-film transistor T 11 comprises an eleventh gate terminal g 11 , an eleventh source terminal s 11 , and an eleventh drain terminal d 11 ; the twelfth thin-film transistor T 12 comprises a twelfth gate terminal g 12 , a twelfth source terminal s 12 , and a twelfth drain terminal d 12 ; and the thirteenth thin-film transistor T 13 comprises a thirteenth gate terminal g 13 , a thirteenth source terminal s 13 , and a thirteenth drain terminal d 13 , wherein the tenth gate terminal g 10 and the tenth source terminal s 10 are connected to the third clock signal input terminal 32 ; the tenth drain terminal d 10 is electrically connected to a pull-down point K n , the eleventh drain terminal d 11 , the twelfth gate terminal g 12 , and the thirteenth gate terminal g 13 ; the eleventh gate terminal g 11 is electrically connected to the first drain terminal d 1 , the thirteenth drain terminal d 13 , the seventh gate terminal g 7 , the ninth drain terminal d 9 , and said one end of the capacitor C b ; the eleventh source terminal s 11 is electrically connected to the second low level input terminal 26 ; the twelfth drain terminal d 12 is electrically connected to said opposite end of the capacitor C b , the eighth drain terminal d 8 , and the first output terminal 27 (G n ); the twelfth source terminal s 12 is electrically connected to the first low level input terminal 25 ; and the thirteenth source terminal s 13 is electrically connected to the first low level input terminal. [0084] The twelfth thin-film transistor T 12 is provided generally for maintain a low voltage of the first output terminal 27 (G n ); the thirteenth thin-film transistor T 13 is provided for maintain a low voltage of the pull-down point Q n ; the eleventh thin-film transistor T 11 is provided for setting the pull-down points P n and K n at a low voltage when Q n is at a high voltage and for deactivating the second pull-down holding unit 47 to prevent the pull-down point Q n from affecting the first output terminal 27 (G n ). The second low level V ss2 being smaller than the first low level V ss1 helps reduce leakage currents of the twelfth and thirteenth thin-film transistors T 12 , T 13 . [0085] Referring to FIG. 5 , in the drawing, signals CK 1 and CK 2 are two clock signals of which the low voltages are opposite at a give time point; the second low level V ss2 is smaller than the first low level V ss1 ; and G n and G n+1 are the output signals of the second output terminals 27 of two adjacent GOA units. It can be seen that Q n and G n can be pulled down to the low voltage of V ss1 and P n and K n can be pulled to the low voltage of V ss2 when Q n and G n are at the high voltage. In this way, the relative potential V gs between the gate terminal and the source terminal of the eighth and ninth thin-film transistors T 8 , T 9 and between those of the twelfth and thirteenth thin-film transistors T 12 , T 13 is less than 0 (V gs =V ss2 −V ss1 ). Since the minimum leakage current of a thin-film transistor in an OFF state is at a location where the relative potential V gs between the gate terminal and the source terminal is less than 0 (as shown in FIG. 6 ), the GOA circuit of the instant embodiment can effectively reduce the leakage currents of the eighth and ninth thin-film transistors T 8 , T 9 and the twelfth and thirteenth thin-film transistors T 12 , T 13 . [0086] Referring to FIGS. 7-8 , which shows a GOA circuit according to another embodiment of the present invention provides, in the instant embodiment, the first pull-down holding unit 46 further comprises a fourteenth thin-film transistor T 14 and the fourteenth thin-film transistor T 14 comprises a fourteenth gate terminal g 14 , a fourteenth source terminal s 14 , and a fourteenth drain terminal d 14 , wherein the fourteenth gate terminal g 14 is connected to the third clock signal input terminal 32 ; the fourteenth drain terminal d 14 is electrically connected to the sixth drain terminal d 6 , the seventh drain terminal d 7 , the eighth gate terminal g 8 , and the ninth gate terminal g 9 ; and the fourteenth source terminal s 14 is electrically connected to the sixth gate terminal g 6 , the sixth source terminal g 6 , and the second clock signal input terminal 31 . The second pull-down holding unit 47 further comprises a fifteenth thin-film transistor T 15 and the fifteenth thin-film transistor T 15 comprises a fifteenth gate terminal g 15 , a fifteenth source terminal s 15 , and a fifteenth drain terminal d 15 , wherein the fifteenth gate terminal g 15 is connected to the second clock signal input terminal 31 ; the fifteenth source terminal s 15 is electrically connected to the tenth source terminal s 10 , the tenth gate terminal g 10 , and the third clock signal input terminal 32 ; and the fifteenth drain terminal d 15 is electrically connected to the tenth drain terminal d 10 , the eleventh drain terminal d 11 , the twelfth gate terminal g 12 , and the thirteenth gate terminal g 13 . [0087] In the instant embodiment, the first and second pull-down holding units 46 , 47 are improved in respect of the drawback of the diode design of the sixth thin-film transistor T 6 and the tenth thin-film transistor T 10 by additionally including the fourteenth thin-film transistor T 14 and the fifteenth thin-film transistor T 15 to discharge to the pull-down points P n and K n in order to fast pull the potentials of the pull-down points P n and K n down to the low voltage of the first clock signal CK 1 or the second clock signal CK 2 the low voltage. Through the alternative operations of the first and second pull-down holding units 46 , 47 , the potentials of P n and K n following variations of the first clock signal CK 1 and the second clock signal CK 2 to change up and down can be achieved, providing alternating operations thereby reducing the influence of the eighth and ninth thin-film transistors T 8 , T 9 and the twelfth and thirteenth thin-film transistor sT 12 , T 13 by stress. [0088] Referring to FIGS. 9-10 , which show a GOA circuit according to a further embodiment of the present invention, the instant embodiment is generally similar to the embodiment with reference to FIG. 7 and a difference therebetween is that in the instant embodiment, the second and third clock signal input terminals 31 , 32 of the first and second pull-down holding units 46 , 47 are replaced by first and second low frequency signal input terminals 34 , 35 and the first and second low frequency signal input terminals 34 , 35 receive inputs of low frequency or ultralow frequency signals LC 1 and LC 2 . This helps reduce power consumptions of the first and second pull-down holding units 46 , 47 , because the first and second pull-down holding units 46 , 47 are constantly kept in operating conditions and for a large number of stages included in the GOA circuit, high frequency signals would increase the power consumption of the GOA circuit. [0089] In summary, the present invention provides a GOA circuit, which uses two low level signals to reduce the leakage currents of the thin-film transistors of a pull-down holding unit, wherein the second low level that has a lower level provides a low voltage to pull-down points P n and K n and the first low level that has a higher level provides a low voltage to the pull-down points Q n and G n , so as to reduce the potentials of the pull-down point P n and K n when the pull-down point Q n and G n are activated to thereby facilitate charging of Q n and G n and also to break the leakage current loop of the circuit between two low level signals to greatly reduce the leakage current between the two low level signal, enhance the performance of the GOA circuit, and improve the quality of displayed images; further, the fourteenth thin-film transistor and the fifteenth thin-film transistor are additionally included in respect of the diode design of the sixth thin-film transistor and the tenth thin-film transistor to perform discharging to the pull-down points P n and K n , thereby achieving the potentials of P n and K n changing up and down with the variation of the first clock signal CK 1 and the second clock signal CK 2 , providing alternating operations so as to reduce the influence of the eighth and ninth thin-film transistor and the twelfth and thirteenth thin-film transistor by stresses, extending the lifespan of the GOA circuit. Further, using low frequency or ultralow frequency signals to control the pull-down holding unit effectively reduces power consumption of the circuit. [0090] Based on the description given above, those having ordinary skills of the art may easily contemplate various changes and modifications of the technical solution and technical ideas of the present invention and all these changes and modifications are considered within the protection scope of right for the present invention.

The present invention provides a GOA (Gate-Driver-on-Array) circuit, which includes multiple GOA units connected in cascade. An nth stage GOA unit of the GOA circuit includes a first (n−1)th stage signal input terminal ( 21 ), a second (n−1)th stage signal input terminal ( 22 ), a (n+1)th stage signal input terminal ( 23 ), a first clock signal input terminal ( 24 ), a first low level input terminal ( 25 ), a second low level input terminal ( 26 ), a first output terminal ( 27 ), and a second output terminal ( 28 ). The nth stage GOA unit further includes: a pull-up control unit ( 42 ), a pull-up unit ( 44 ), a first pull-down holding unit ( 46 ), a second pull-down holding unit ( 47 ), and a pull-down unit ( 48 ). The GOA circuit of the present invention overcomes the problems of poor performance of the conventional the GOA circuit caused by introduction of two low level signals into the GOA circuit and short operation service life and can enhance the quality of displayed images.

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is a continuation of U.S. patent application Ser. No. 11/562,467, filed Nov. 22, 2006. TECHNICAL FIELD [0002] This invention generally relates to communications. More particularly, this invention relates to wireless communications. DESCRIPTION OF THE RELATED ART [0003] In a UMTS or CDMA radio access network (RAN) deployment a geographical area is divided into cells. A nodeB (UMTS terminology) or base station (CDMA terminology) serves each cell. To assist with mobile station mobility between cells, the RAN maintains a list of neighboring cells for every cell in the network. The mobile station must learn of the neighboring cells so that it can detect signal strengths for selecting a candidate cell for future communications. [0004] Mobility can be broadly split into two mobile station modes: idle mode mobility and active mode mobility. In idle mode, the mobile station has no active radio links to the RAN, so mobility involves choosing a nodeB or base station with a good enough signal strength upon which to “camp”. When camped, the mobile station can listen to the nodeB or base station broadcast channels. This is important because the broadcast channels are used to signal an incoming phone call. The broadcast channels are also used to inform all mobile stations of neighboring cells to be considered for camping on. In active mode, the mobile station has active radio links to the RAN. As the radio channel conditions change between the mobile station and the nodeB or base station, other nodeBs or base stations must be considered as candidates with which to maintain the communication link. [0005] It is expected that the deployment of macro-cellular networks (e.g., existing cellular networks) will be complemented by the deployment of in building (e.g., home, enterprise, government) communication devices that operate as microcell or picocell nodeBs or base stations. The former can be considered an underlay network and the latter an overlay network because the latter will be, in effect, established on top of or in addition to the macro-cellular network. The in-building overlay network will be intended to complement the macro-cellular, underlay network. [0006] Establishing overlay networks will increase cellular coverage and capacity. However, it heralds a new deployment scenario that current specifications and standards are not designed to provide. There are a number of problems associated with this, including how to provide mobile station mobility between the traditional macro-cellular network deployment and the overlay deployment. [0007] In most cases, the mobile station relies on the RAN to inform of it of the presence of neighboring cells (nodeBs and base stations) and their cell codes (scrambling codes or pseudo noise offsets). Neighboring cells use different cell codes compared to those around them to enable the mobile station to separate the transmissions of interest from those of other cells. The number of neighbors is limited to a set of 32 intra-frequency cells. If an overlay network is deployed, the number of neighbors can become much greater than 32. It is possible to have hundreds of apartments inside one underlay cell, for example, with each apartment containing an overlay cell. There needs to be a mechanism to inform the mobile station of all neighbors so they can be considered as a candidate for camping or handoff. [0008] One suggestion is to modify the RAN infrastructure to inform it of the overlay network's presence. For example, a radio network controller could be informed of every cell in the overlay network that the mobile station is permitted to use. Then, when the mobile station is informed of neighbors through messages transmitted by the RAN the list is augmented with mobile-station-specific nodeBs. Providing mobile-station-specific neighbor lists overcomes the limitation of 32 intra-frequency neighbor cells but it increases the task and complexity of maintaining up-to-date neighbor lists. Overlay network devices may be arbitrarily introduced into or removed from a macro-cell coverage area and the RAN would need to be updated accordingly on an inconveniently frequent basis. Additionally, modifying the RAN in this manner does not solve the idle mode mobility problem. In idle mode, no active radio link exists between the mobile station and the RAN. The mobile station therefore relies on the underlay network broadcast channels to inform it of candidate cells upon which to camp. In idle mode there is no facility to provide a mobile-station-specific neighbor list. [0009] Another suggestion instead of modifying the RAN is to modify the mobile station to store the list of overlay cells it is allowed to access. Then the mobile station adds its stored set of potential candidates to any neighbor list received from the RAN. This requires changing the way current mobile stations operate and hinders simple deployment of an overlay network. Existing mobile stations would have to be reconfigured to have the necessary capacity for this feature. [0010] Both of the above suggestions have the drawback of requiring substantial changes to existing equipment (mobile station or RAN). This is expensive, carries significant risk and is unattractive to the network operator. [0011] There is a need for an efficient and economical way of facilitating a mobile station communicating with an overlay network within the coverage area of a macro-cellular underlay network. This invention addresses that need. SUMMARY [0012] An exemplary method of communication is useful in a system including at least one underlay network device having a first coverage area and at least one overlay network device having a second, smaller coverage area within the first coverage area of the underlay network device. The exemplary method includes using a selected plurality of cell codes for identifying overlay network devices exclusively. Communications are conducted using a selected plurality of cell codes exclusively for identifying overlay network devices. The first downlink channel has one of the selected plurality of cell codes such that a mobile station communicating with an underlay network device can detect the overlay network device as a candidate overlay network device for communications with the mobile station. [0013] An exemplary communication device comprises a transmitter that broadcasts at least two downlink channels. A cell code of a first one of the downlink channels is one of a selected plurality of cell codes used for identifying overlay network devices exclusively. A cell code of a second one of the downlink channels is distinct from the selected plurality of cell codes. [0014] The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 schematically shows selected portions of a wireless communication system with which an embodiment of this invention is useful. [0016] FIG. 2 is a flowchart diagram summarizing one example approach. DETAILED DESCRIPTION [0017] The following description demonstrates how example embodiments of this invention allow for a mobile station to communicate with underlay network devices (e.g., macro-cell base stations) and overlay network devices (e.g., pico-cell base stations) within the coverage area of the underlay network. The disclosed examples are useful for a variety of communication scenarios including active call handovers between the underlay and overlay networks and idle mode candidate cell identification of underlay cells, overlay cells or both. The disclosed examples facilitate employment of overlay networks and devices within areas covered by existing underlay network devices in an efficient and economical manner. [0018] FIG. 1 schematically shows an example communication system 20 . An overlay network 22 includes a plurality overlay network communication devices 22 that provide wireless communication coverage in corresponding cells. In a UMTS example, the devices 22 are nodeBs and in a CDMA example, the devices 22 are base station transceivers. Only one such device is shown in FIG. 1 for simplicity. Each of the devices 22 provides a coverage area for a corresponding one of a plurality of cells 26 , 28 , 30 , 32 and 34 . The size of the cells 26 - 34 is such that the cells are considered macrocells. [0019] Other communication devices 40 provide wireless communication coverage areas or cells 42 within the coverage areas of the cells 26 - 34 . Only one such device is shown for simplicity but there would be one associated with each of the cells 42 schematically shown in FIG. 1 . The communication devices are considered part of an overlay network for purposes of discussion because the wireless coverage provided by the devices 40 complements and is placed on top of that provided by the overlay network devices 24 . [0020] Each communication device 40 includes a transceiver such that it operates as a nodeB or base station of the corresponding cell 42 . [0021] Mobile stations can communicate with the communication devices 24 , the communication devices 40 , or both, depending on the situation of the particular mobile station. The illustrated example includes a mobile station 50 within the cell 28 and another mobile station 52 within the cell 34 . The mobile station 50 is not within a coverage area of any of the overlay network cells 42 and can only communicate with the underlay network devices 24 . The mobile station 52 , on the other hand, is within the coverage area of one of the overlay cells 42 and the underlay cell 34 . The illustrated example provides the mobile station 52 an ability to communicate with either network by communicating with either or both of the corresponding communication device 24 and the corresponding communication device 40 . In other words, the mobile station 52 has mobility between the overlay and underlay networks. [0022] One example approach is summarized in a flow chart 60 in FIG. 2 . This example includes the mobile station 52 being powered on at 62 . Initially, the mobile station uses known techniques for camping on a channel of the underlay network. This status is shown at 64 . In a known manner, the mobile station 52 receives a neighbor list of cell codes (e.g., scrambling codes or pseudo noise offsets) from the underlay network 22 as shown at 66 . [0023] One example includes cell codes within the neighbor list provided by the underlay network 22 that notify a mobile station of the communication devices 40 of the overlay network within the region of the current mobile station location. One example includes reserving a relatively small number of cell codes exclusively for identifying the cells 42 of the overlay network. In one UMTS example, eight of the 512 available scrambling codes are used exclusively for identifying the cells 42 . In one CDMA example, a plurality of PN offsets are used exclusively for identifying the overlay cells 42 . [0024] In one example, every overlay communication device 40 broadcasts two downlink channels instead of just one. A first one of the downlink channels has one of the cell codes that is exclusively dedicated to identifying the overlay cells 42 . The second one of the two downlink channels has a cell code that is distinct from those in the reserved set used exclusively for identifying the cells 42 . The first downlink channel can be considered a “transitory” broadcast channel because it provides information that facilitates mobile station mobility between the overlay network and the underlay network 22 . The second downlink channel is a “normal” broadcast channel because it is used for communications within an overlay cell 42 in a manner like the normal broadcast channels are used in the overlay cells 26 - 34 . The cell code of the second downlink channel is chosen so that it does not conflict with any neighbor cell codes in the underlay or overlay network. [0025] The neighbor list of the underlay network, which is provided by the traditional RAN is modified in one example to always include the reserved set of cell codes that exclusively identify the overlay cells. The mobile station receiving the neighbor list performs signal strength measurements at 68 to evaluate potential candidate cells on which the mobile station can camp. Because the neighbor list include those cell codes that exclusively identify overlay cells 42 , the mobile station will be monitoring overlay communication device 40 transitory downlink channel broadcasts. [0026] At this stage, the mobile station is informed of the overlay network's presence. The mobile station will now perform signal strength measurements on the reserved cell codes. The overlay cells will therefore be considered as camping candidates and as active mode handover candidates. [0027] At 70 , the mobile station determines whether to switch from a current cell. If not, the mobile station operation returns to 64 . If a monitored broadcast downlink channel indicates that a switch is desirable, a determination is made at 72 , whether the new cell selected by the mobile station is an overlay cell 42 . If so, the mobile station camps on the transitory downlink channel (e.g., the first of the two downlink channels) of the corresponding overlay cell 42 at 74 . Then the mobile station can identify the second of the downlink channels of the corresponding overlay cell 42 based on communications on the first (e.g., transitory) of the downlink channels on which the mobile station has camped. [0028] Essentially, the two downlink channels radiating from a single overlay communication device 40 result in two different cells being presented to the mobile station. A mobile station informed by the underlay network will only be aware of one of these cells (i.e., the “transitory” cell code). Once the mobile station camps on the transitory cell, however, the transitory broadcast channel (BCH) broadcast messages will then inform the mobile station of the second of the two downlink channels (e.g., the “normal” cell). In one UMTS example, the transitory cell's BCH System Information Block 11 (SIB 11 ) is populated to contain the normal cell's cell code. [0029] To reduce radio interference, the transitory downlink channels are only used for a short time in one example in order to bridge the overlay and underlay networks. At 76 , the mobile station determines signal strengths of the neighbor set provided by the overlay communication device 40 . [0030] One example includes fixing the power of the transitory channels to be a fraction of the normal downlink channels of the overlay cells. The second downlink channel cell code is included in the transitory broadcast channel neighbor list. In the transitory broadcast channels of one example, the signal strength at which the mobile station evaluates other candidates for camping on is set very low. In a UMTS example, this parameter is called S intrasearch , included in SIB 3 / 4 messages, which are known from 3GPP specifications 25.304, for example. The mobile station selects the normal cell code associated with the second of the two downlink channels due to its higher signal strength. The mobile station camps on a normal overlay cell channel at 78 . [0031] Once the mobile station camps on the normal overlay cell 42 , it may be desirable that it remains camped on it, even if another cell becomes a better candidate. For example, a network operator's goal may be to take traffic off their macro-cellular network and direct it onto the overlay cells 42 . This is achieved in one example by setting parameters in the BCH channels appropriately. For example, thresholds for starting the cell-reselection procedure are set very high. [0032] In another example, once handover is complete to the transitory overlay cell, the overlay communication device 40 instructs the mobile station to handover to the normal cell of the overlay device 40 . [0033] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.

A wireless communication technique provides mobility for a mobile station to communicate with an overlay network device, which is within a coverage area of an underlay network device, when the mobile station is within a coverage area of both devices. The overlay network device broadcasts at least two downlink channels. A cell code (e.g., a scrambling code or pseudo noise offset) of a first one of the downlink channels identifies an overlay network device exclusively. The mobile station can detect the first downlink channel responsive to an indication of the exclusive cell code from the underlay network device. A second one of the downlink channels allows for subsequent, ongoing communications between the mobile station and the overlay network device.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 13/107,546, filed May 13, 2011, which is a continuation of U.S. patent application Ser. No. 11/764,005, filed Jun. 15, 2007, which was a division of U.S. patent application Ser. No. 10/887,320 filed Jul. 9, 2004, which subsequently issued as U.S. Pat. No. 7,548,153 on Jun. 16, 2009. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to interrogatory systems. More particularly, the present invention relates to an interrogatory system having closely-spaced interrogators that simultaneously process different tag protocols or commands. [0004] 2. Background of the Related Art [0005] As discussed in U.S. Pat. No. 5,030,807 to Landt, RFID (radio frequency identification) systems use frequency separation and time domain multiplexing in combination to allow multiple interrogators to operate closely together within the bandwidth limitations imposed by radio regulatory authorities. In transportation and other applications, there is a compelling need for interrogators to operate in close proximity. In the example of a toll collection system, many lanes of traffic are operated side by side, and it becomes necessary to simultaneously read tags that are present in each lane. This introduces new challenges, particularly when a system is designed to communicate with tags of differing protocols, requiring performance sacrifices. [0006] Backscatter RFID systems, because they are frequency agile, can use frequency separation to allow simultaneous operation of closely-spaced interrogators. However, the ability to operate with acceptable performance is limited by the ability of the interrogator to reject adjacent channel interference, and in the case where frequencies are re-used, co-channel interference. In addition, the interference impact of operating multiple interrogators in close proximity to one another is complicated by second and third order inter-modulation effects. Because the downlinks (interrogator to tag) are modulated signals and the uplink signals (tag to interrogator) are continuous wave (CW) carriers at the interrogator, the interference on an uplink by a downlink is more severe in most cases than either downlink on downlink interference or uplink on uplink interference. When downlink on uplink interference debilitates performance beyond an acceptable level, the system could be set up for time division multiplexing among the interrogators. Interrogators would then share air time (take turns) according to a logic scheme to minimize or eliminate the impact of the interference between interrogators. That, however, results in lower speed performance since a given transaction requires more total time to complete. When a large number of lanes are involved, the speed performance loss can be severe and unacceptable. [0007] Active RFID systems typically cannot use frequency separation due to the fact that cost-effective active transmitters operate on a fixed frequency. These systems have therefore followed an approach of operating in a pure time division mode to prevent interference among closely located interrogators. [0008] Downlink on downlink interference typically occurs when a tag receives the signals from two interrogators. If the interrogators are closely spaced, the RF level of the two transmitted bit streams may be comparable. If significant RF from the adjacent interrogator is received during bit period when none should be received, the tag may incorrectly decode the message. [0009] From a self-test perspective, RFID systems typically utilize what is commonly known as a “check tag” to provide a level of confidence regarding the health of the RFID system. The check tag can be an externally powered device that responds only to a specific command or responds only to its programmed identification number. It can be built into the system antenna or it can be mounted on or near the system antenna. It can also be housed within the interrogator and coupled to the system antenna via a check tag antenna mounted near the system antenna. Though the check tag can take a variety of forms, one commonality is that the check tag must be activated in some manner so that the response can be read by the interrogator and remain inactive during normal operation. [0010] When a check tag is activated, it typically provides a response that can be read by the interrogating device. The check tag response is generally the same as what would be received by the interrogator during normal operation as a tag passes through the system in that particular application. If a backscatter RFID system initiates a check tag and a response is received, it verifies the RFID system is operational to the point that RF has been transmitted and the check tag backscatter response received and decoded. Encoded modulation of the RF is only verified if the check tag requires a modulated signal to trigger its response. The time that it takes to complete the cycle depends upon the type of tag utilized and can range from a few to several milliseconds, and the cycle is repeated periodically. SUMMARY OF THE INVENTION [0011] It is therefore one object of the present invention to provide an interrogating system that is able to simultaneously operate a plurality of closely-spaced interrogators. It is another object of the invention to provide an interrogating system that synchronizes a plurality of interrogators. It is another object of the invention to provide a system that simultaneously processes different protocols used to communicate with tags. It is another object of the invention to provide a system that simultaneously processes different backscatter protocols. It is yet another object of the invention to provide a system that simultaneously processes different active and backscatter protocols. It is yet another object of the invention to provide an interrogating system that avoids interference on an uplink by a downlink, as well as downlink on downlink interference, and uplink on uplink interference. It is yet another object of the invention to provide a self-test operation that can verify operation of the interrogator and that does not have the time constraints of the check tag. It is another object of the invention to provide an interrogation system in which uplink signals are received, and downlink signals are sent, over a single antenna. [0012] In accordance with these and other objects of the invention, a multi-protocol RFID interrogating system is provided that employs a synchronization technique (step-lock) for a backscatter RFID system that allows simultaneous operation of closely spaced interrogators. The interrogator can read both active and backscatter tags more efficiently when combined with time division multiplexing. The multi-protocol RFID interrogating system can communicate with backscatter transponders having different output protocols and with active transponders, including: Title 21 compliant RFID backscatter transponders; IT2000 RFID backscatter transponders that provide an extended mode capability beyond Title 21; EGO™ RFID backscatter transponders, SEGO™ RFID backscatter transponders; ATA, ISO, ANSI AAR compliant RFID backscatter transponders; and IAG compliant active technology transponders. [0013] The system implements a step-lock operation, whereby adjacent interrogators are synchronized to ensure that all downlinks operate within the same time frame and all uplinks operate within the same time frame. The step-lock operation allows for improved performance with higher capacity of the RFID system. Active and backscatter technologies are implemented so that a single interrogator can read tags of both technology types with minimal interference and resulting good performance. [0014] The step-lock operation eliminates downlink on uplink interference. Because downlink on uplink interference is the most severe form of interrogator-to-interrogator interference, that has the net impact of reducing the re-use distance of a given frequency channel significantly. The step-lock technique can be extended to reduce or eliminate downlink on downlink interference for fixed (repeating) downlink messages. This can be achieved by having the interrogators transmit each bit in the downlink message at precisely the same time. Depending on radio regulations and the number of resulting available frequency channels with a given backscatter system, that can allow re-use distances sufficiently close that an unlimited number of toll lanes can be operated without any need to time share among interrogators, drastically improving performance and increasing capacity of the overall RFID system. [0015] Step-locking of the interrogators allows the interrogators to operate in a multi-protocol mode, whereby the same interrogator can read both active and backscatter tags in a more efficient way. This is accomplished by combining a time division strategy for active transponders and the step-locked frequency separation strategy for backscatter tags into one unified protocol. BRIEF DESCRIPTION OF THE FIGURES [0016] FIG. 1 is a block diagram of interrogators in a step-lock configuration where the synchronization signal is generated by the interrogator in a Master/Slave mode; [0017] FIG. 2 is a block diagram of interrogators in a step-lock configuration where the synchronization signal is generated by an external source; [0018] FIG. 3( a ) is a timing diagram of the step-lock feature showing the uplinks, downlinks, and processing times for multiple interrogators; [0019] FIG. 3( b ) is a timing diagram at the bit level; [0020] FIG. 3( c ) is a timing diagram of the step-lock feature having a time division multiplex; [0021] FIG. 4 is a preferred block diagram of the interrogator; [0022] FIG. 5 is a block diagram of the synthesized sources 33 , 45 of FIG. 4 ; [0023] FIG. 6 is a block diagram of the dual mixer configuration 56 of FIG. 4 ; [0024] FIG. 7 is a block diagram of the DOM DAC and modulation control 60 of FIG. 4 ; [0025] FIG. 8 is a block diagram of the power amplifier 65 and its peripherals of FIG. 4 ; [0026] FIG. 9 is a block diagram of the downlink/uplink DACs and power control 72 of FIG. 4 ; [0027] FIG. 10 is a block diagram of the interrogator showing the loop-back built-in-test capability; [0028] FIG. 11 is a block diagram of the interrogator showing the test tag built-in-test capability with a coupling antenna; [0029] FIG. 12 is a block diagram of the interrogator showing the test tag built-in-test capability with a directional coupler; [0030] FIG. 13 is a lane plan for the system showing the downlink frequencies for a single protocol having different command sequences; [0031] FIG. 14 is a lane plan for the system of FIG. 13 , showing the uplink frequencies; [0032] FIG. 15 is a timing chart for the system of FIGS. 13 and 14 , showing the command sequences; [0033] FIG. 16 is a lane plan for the system showing the downlink frequencies for active transponders and backscatter transponders; [0034] FIG. 17 is a lane plan for the system of FIG. 16 , showing the uplink frequencies; [0035] FIG. 18 is a timing chart for the system of FIGS. 16 and 17 , showing the protocol sequences; [0036] FIGS. 19 and 20 are lane plans for the system showing the downlink and uplink frequencies for active transponders and backscatter transponders; and, [0037] FIG. 21 is a timing chart for the system of FIGS. 19 and 20 , showing the protocol sequences. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0038] In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings that form a part hereof and in which is shown by way of illustration a specific embodiment in which the invention may be practiced. This embodiment is described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural or logical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. [0039] Turning to the drawings, FIG. 1 is a block diagram of the overall system 10 in accordance with a preferred embodiment of the invention. The system 10 depicts a single cluster of interrogators 12 and hosts or controllers 14 in a step-lock configuration, and various active or backscatter transponders 11 . As shown, the interrogators 12 communicate with the transponders 11 in accordance with various tag protocols, Tag Protocol 1 and Tag Protocol 2. The controller 14 controls and interfaces various system components, such as the associated interrogator 12 , vehicle detection, and video enforcement, as may be required by the specific application. [0040] One interrogator 12 is designated as the master, while the rest of the interrogators 12 are designated as slaves. The master interrogator 12 generates a synchronization signal 16 and transmits it to the slave interrogators 12 . The interrogators 12 are connected together via an RS-485 interface for multipoint communication in half-duplex operation, and the synchronization signal 16 is transmitted over that line. The overriding factors in master/slave designation are the timing parameters set in the respective interrogators 12 versus the reception of the synchronizing signal 16 . The timing parameters are set in each interrogator 12 , such that the subsequent slave can become the master in the event of a failure. [0041] The interrogator 12 preferably has a single antenna 18 that is used to transmit the modulated downlink signal to interrogate a transponder 11 . The single antenna 18 also transmits the CW uplink signal required to receive the backscatter response of a backscatter transponder. In addition, the single antenna 18 receives the response from an active transponder 11 . [0042] FIG. 2 is a block diagram of the system 20 , showing interrogator clusters 22 and associated hosts or controllers 24 in a step-lock configuration. An external source 26 is provided that generates the synchronization signal 28 . In the preferred embodiment, the external source 26 is a GPS receiver that has a 1 pps (pulse per second) signal that is utilized to enable synchronization of the respective clusters 22 . The master interrogator locks a reference clock to the GPS 1 pps signal, and uses the reference clock to generate the synchronization signal that is sent to the slave interrogators. The timing of the 1 pps signal from a GPS unit is very precise, which allows each of the clusters to be synchronized together in time. This configuration is utilized when distance, or some other physical impediment, does not allow for a direct connection of the clusters 22 . Generally, one GPS receiver is required per cluster 22 , and the interrogators 22 can then be connected as shown in FIG. 1 to synchronize the cluster to the external source. [0043] FIG. 3( a ) is a timing diagram showing several interrogators 10 operating in step-lock. The diagram shows that all of the interrogators 12 transmit their uplink and downlink signals at the same time. When interrogators 10 are step-locked, the timing for each interrogator 10 is controlled so that the uplinks and downlinks all start and end at the same time. That reduces interference caused by one interrogator's downlink signal interfering with another interrogator's uplink signal. By utilizing different frequency plans among the various tag protocols, the number of interrogators in a particular cluster can be increased. [0044] As shown in FIGS. 1-2 , the system polls a Title 21 backscatter transponder for specific information, and then polls an EGO backscatter transponder for specific information and the respective transponders respond accordingly. Each interrogator 12 transmits a Tag Protocol 1 signal and Tag Protocol 2 signal to each of the transponders 11 . The Title 21 backscatter tags 11 provide a backscatter response to the corresponding Title 21 protocol signal, Tag Protocol 1, and the EGO backscatter tags 11 provide a backscatter response to the corresponding EGO protocol signal, Tag Protocol 2. [0045] FIG. 3( a ) shows the timing required to support two tag protocols. As depicted, the first tag protocol, Tag Protocol 1, has downlink and uplink periods that differ from the downlink and uplink durations of the second tag protocol, Tag Protocol 2. The tag protocols may also have different processing times that follow the uplink of data. Thus, if the tag protocols are left unsynchronized, there is the strong potential that the downlink for either the first or second protocol of one interrogator would interfere with the uplink for either the first or second protocol of another interrogator. To avoid that interference, the interrogators are step-locked so that the downlinks of the first tag protocol end at the same time for all of the interrogators, and the downlinks of the second tag protocol also end at the same time for all of the interrogators, as shown in the figure. The timing is controlled by a synch signal at the beginning of each cycle, which triggers the downlink signal of Tag Protocol 1. [0046] If only those two types of tags are being interrogated, then the signal pattern in FIG. 3( a ) would repeat itself. If more tag protocols are used, then the uplink and downlink signals for the additional tags are transmitted before the pattern is repeated. In some cases, a particular tag protocol may be transmitted multiple times before the interrogators switch to a different protocol, such as if the tag needs to be read multiple times or if the tag is read and then put to sleep by an additional command. [0047] Thus, the protocols are preferably implemented in a serial fashion, whereby each interrogator cycles through the various protocols before repeating the pattern and all the interrogators are processing the same protocol. That is, the downlink and uplink signals for Tag Protocol 1 are processed by all of the interrogators at the same time, followed by a processing time and the downlink and uplink signals for Tag Protocol 2. It should be apparent to one skilled in the art that the protocols need not be aligned in a serial fashion, but can be run simultaneously in a parallel fashion by synchronizing the downlink times across the different protocols. That is, a first interrogator can process a first protocol downlink signal while a second interrogator processes a second protocol downlink signal. This type of step-lock is illustrated with respect to commands of a single protocol, for instance, in FIG. 18 , which is discussed below. [0048] However, having the interrogators process the same protocols minimizes any delay between the various signals due to the different signaling durations of the various protocols. For instance, if Interrogator 1 processes Tag Protocol 1 and Interrogator 2 processes Tag Protocol 2, a delay would have to be introduced before the downlink of Tag Protocol 1 since the downlink of Tag Protocol 2 is much longer, so that Tag Protocol 1 is not uplinking while Tag Protocol 2 is still downlinking. As shown in FIG. 18 , the time for each transmission is increased to allow for the longest command, which is the select or read command of the EGO protocol. [0049] FIG. 3( b ) is a diagram showing the step-lock technique extended to the bit synchronization level for the signals of FIG. 3( a ). Each interrogator is step-locked and the transmission of each bit in the downlink message is transmitted at precisely the same time. For bit synchronization, the exact same command (bit for bit) has to be transmitted by each interrogator and is intended for protocols that satisfy that criteria. [0050] FIG. 3( c ) shows the timing using a time division multiplexing and step-lock synchronization for an application that includes both active and backscatter transponders. The synch signal initiates the signal cycle, which in this case starts with the first set of interrogators, Interrogators 1, 4, 7, generating a transmit pulse in accordance with Tag Protocol 1, the active tag protocol. [0051] The active protocol is sent in accordance with a time division multiplex scheme. The transmit pulses are offset to prevent interference that corrupts data received by the reader which might otherwise result from closely located tags. Accordingly, the active protocol is divided into three time slots. In the first slot, the first interrogator and every third interrogator transmit the downlink for the active tag protocol. Following the transmission of the downlink, every interrogator looks for a response from the tag. If an interrogator that transmitted the downlink receives a response, that interrogator assumes that the tag is under its antenna. If an interrogator that did not transmit the downlink receives a response, that interrogator assumes that the tag is under the antenna of a different interrogator. The interrogator will preferably ignore responses of tags that under the antenna of a different interrogator. [0052] In the second and third time slots, the other interrogators transmit in their respective slots, and each interrogator uses the same logic on the received signals to decide if a tag response is under their antenna. Following the completion of the active tag protocol, every interrogator transmits the backscatter protocol downlink, and then looks for the backscatter uplink signal from the tag. Interrogators [0053] The multiple protocols supported by the interrogator translate to the specific requirements of the respective transponders. The tags can be passive or active, battery or beam powered, with additional variables that are dictated by the physics of the transponder. Thus, the interrogators 12 must be able to accommodate the different variables and requirements for active and passive tags, as well as the different commands and backscatter protocols. In addition, the interrogators 12 must be capable of adjusting itself to handle different protocol power levels, depths of modulation, duty cycle, speed (bit rates), frequency of transmissions, receiver range adjustments, as well as tag and interrogator sensitivity. [0054] Since the interrogator controls the power of the signal reflected by a backscatter transponder, the uplink RF power level is utilized to set the respective uplink capture zone for a backscatter transponder. The downlink RF power level is used to communicate with a transponder that requires a modulated command (Title 21, IT2000, EGO, SEGO backscatter transponders), or a trigger pulse (active transponder), before the device will respond. Thus, the RF downlink power is utilized to establish a downlink capture zone for the transponders specified, and in the case of backscatter transponders, can be different than the uplink RF power level. In addition, the RF power level required by a beam powered transponder is much greater than that required by a battery powered transponder. Closed loop control is implemented to maintain tight control of the dynamic RF power level that is required by the system. [0055] The requirement to support multiple depth of modulation (DOM) levels is necessary due to the fact that the transponder receiver dynamic range is dependent upon the DOM transmitted during the downlink. The base band path of the respective transponders can be AC or DC coupled where the DC coupled path typically requires a larger modulation depth. Closed loop control is implemented to maintain control of the dynamic DOM level from protocol to protocol. [0056] The ability to adjust duty cycle provides the flexibility to compensate for finite non-linearity in the interrogator modulation path and the capability to optimize the duty cycle to the respective transponder requirements. The duty cycle would typically be set at 50% with a small tolerance; however, the ideal for a transponder type could be higher or lower. The adjustment of the duty cycle or pulse width aids in the tuning of the modulated signal to the transponder requirements and in the derivation of transponder sensitivity to variations of duty cycle. [0057] With the exception of the Title 21 and IT2000 protocols, the baud rates are different for all the protocols. The ratio from the fastest protocol to the slowest protocol is in excess of 10-to-1. The interrogator must accommodate the different baud rates from the point of origin within the interrogator through transmission while maintaining control of RF power, DOM and the emission mask. The frequency of transmission, and when to actually transmit, relates to the synchronization period and must be variable in order to accommodate all combinations of protocols and command sequences. [0058] Finite receiver adjustments provide the capability to vary the sensitivity level of the interrogator for each protocol. Ideally, the default would be to have the interrogator sensitivity level of each protocol approximately the same. In a multi-mode application that requires the sensitivity levels of respective protocols to be different, they can be adjusted accordingly. An example is a multiple protocol application with a beam powered transponder of one protocol and a battery powered transponder of another protocol. The capture zone of the battery powered transponder can be adjusted to a certain degree by the level of RF transmitted. The same is true for the beam powered transponder, but to a much lesser degree. If it is desired to align the capture zones, the receiver adjustment provides another degree of freedom. This adjustment is provided for the RF receive path and in the form of threshold levels in the base band receivers that must be exceeded for the signal to pass. This technique is also useful for the elimination of undesirable cross lane reads. [0059] FIG. 4 is a preferred block diagram of the interrogator 12 . The interrogator 12 has a transceiver 30 , and a processor 100 . The transceiver 30 provides the communications link to the transponder, and the processor 100 provides the functional control of the interrogator 10 . The transceiver 30 is comprised of a transmitter chain that generates the amplitude modulation (“AM”) and CW carriers, a receiver to accept and process either the backscatter or active response of the respective transponder, and a controller to interface to the processor and provide the necessary control for the transmit and receive functions. [0060] The transceiver 30 includes a transmitter chain and a receiver chain. The transmitter chain includes sources 33 , 45 , source select 44 , MOD/CW 56 , RF AMP 65 , filter 74 , coupler 76 , isolation 77 and coupler 78 . The receiver chain includes filter 82 , attenuator 84 , select 86 , receivers 88 , 92 , baseband processor 94 , and detectors 90 , 96 . Transmitter [0061] The transmitter chain begins with the generation of two synthesized RF sources, the downlink/uplink source 45 and the dedicated uplink source 33 . The sources 33 , 45 are used to generate the uplink and downlink signals, such as the ones shown in FIG. 3( a ). A downlink/uplink source 45 generates the first synthesized RF signal (S 1 ), which is used as a downlink modulated source to interrogate, activate, and/or trigger a transponder. This source can also be used as an uplink continuous wave (CW) source to provide the communications link for the response of a backscatter tag. The uplink source 33 generates a synthesized RF source (S 2 ), which is used as an uplink CW source to provide the communications link for the response of a backscatter tag. The sources 33 , 45 are synthesized low phase noise sources that aid in providing high backscatter receiver performance with a single antenna. [0062] Turning to FIG. 5 , the sources 33 , 45 include a frequency synthesizer 34 , loop filter 36 , low phase noise voltage controlled oscillator (VCO) 38 , and a coupler 40 . The coupler 40 has a gain block 39 to feedback the VCO 38 output back to the synthesizer 34 to comprise a low phase noise phase lock loop (PLL). The output of the PLL has a high isolation buffer amplifier to provide gain and isolate the PLL from the transmitter chain. The processor 100 initializes the S 1 and S 2 sources to fixed frequencies through the controlling device 43 on the transceiver 30 via the Clock, Data and Load signals. An adjustable oscillator (not shown) provides the reference signal for both the uplink synthesizer 33 and the downlink/uplink synthesizer 45 . The oscillator is adjustable to provide the capability to calibrate to an external standard reference. [0063] Source selection circuitry 44 , comprised of high isolation single-pole, single-throw (SPST) switches, is used for sources 33 , 45 that feed into a high isolation single-pole, double-throw (SPDT) non-reflective switch. That provides the ability to select either source 33 or 45 , while maintaining a high degree of isolation between the sources 33 , 45 to minimize the generation of inter-modulation products. The processor 100 controls the state of the switches through the controlling device 43 on the transceiver 30 . [0064] A local oscillator (LO) 48 for the direct conversion backscatter receiver is coupled off of the output of the SPDT switch 45 . It is fed into a high isolation buffer amplifier (not shown) to provide gain and isolate the transmitter chain from the receiver-portion of the transceiver 30 . The LO level is fixed by a gain block, low-pass filtered and fed into a high isolation SPST switch (not shown) to provide additional isolation from the active receiver. The processor 100 controls the state of the SPDT switch of the source 45 through the controlling device 43 on the transceiver 30 . [0065] The MOD/CW block 56 provides the capability to modulate the respective source or place the source in a CW condition. As shown in FIG. 6 , the MOD/CW block 56 is comprised of a dual mixer configuration separated by a gain block. That configuration provides a high dynamic range of linear AM modulation to aid in reducing the transmitted occupied bandwidth. Though this type of configuration can introduce non-linear second-order effects, utilizing the second mixer to provide the majority of the AM modulation minimizes the distortion. The mixers 56 are driven at base band with the respective protocols bit stream, trigger signal or DC level, respectively, by amplifiers that provide the required drive levels. The drive levels from the amplifiers produce the desired peak level for CW or the “high” and “low” condition when modulating. Transmitter Bit Rate and DOM Adjustment [0066] The difference between the respective data rates of the protocols requires a configuration that can support the data rates for all of the protocols, while maintaining an emission mask that minimizes channel spacing in order to maximize the number of available channels. Bit rate adjustment is handled in the interrogator, FIG. 4 , by the modulation control block 60 , which is shown in greater detail in FIG. 7 . The DOM DAC & Modulation Control 60 utilizes a switch to select between the high-speed path and the low-speed path. The high-speed path accommodates the high-speed protocols, such as Title 21 and IT2000, and a low-speed path accommodates the low-speed protocols, such as EGO, SEGO and a trigger pulse. The controlling device 43 on the transceiver 30 selects the desired path based on the protocol configuration indicated by the processor 100 . Eighth-order low-pass filters provide the desired emission mask for the supported protocols. [0067] The control unit 60 receives a fixed DC reference level (VREF), which sets the level that indicates the transmission of a “high” bit, or CW condition as required, and is the same for all protocols. A digital-to-analog converter (DAC) 70 sets the level that indicates the transmission of a “low” bit, or the DOM (depth of modulation) level, which is retrieved from a memory in the controller 43 as required. The Modulation signal provides true logic control of an SPDT switch that selects either the “high” condition or the “low” condition based on the state of the Modulation signal. [0068] Each protocol that requires a modulated downlink transmission from the interrogator has a corresponding memory location in the controlling device 43 on the transceiver 30 that is calibrated to the DOM level required for that protocol. Switching between the respective DOM levels is handled by the controlling device 43 based on the protocol configuration indicated by the processor 100 . The modulation control unit 60 outputs a Filter Mod signal, which is used by the MOD/CW 56 to modulate the signal in accordance with the desired protocol. Transmitter Power Level Adjustment [0069] The interrogator must also be able to accommodate the various power levels required by the various backscatter protocols and the active transponder protocol. Power adjustment is handled in the interrogator, FIG. 4 , by the RF AMP 65 and the power controller 72 , which are shown in greater detail in FIGS. 8 and 9 . Turning to FIG. 8 , the RF AMP 65 is comprised of a gain block 64 , voltage variable attenuator 66 , RF switch, and a 900 MHz Integrated power amplifier 68 . The gain block 64 provides the desired level into the voltage variable attenuator 66 . The voltage variable attenuator 66 is utilized to vary the RF power based upon a VCTL Attn signal received from the power controller 72 . The attenuator 66 provides a fixed rise time when turning on RF power for CW transmission and also to the DOM level prior to a modulated transmission. [0070] The DL/UL DACs & Power Control 72 is shown in FIG. 9 . A downlink DAC 71 sets the RF peak power level required for a downlink transmission to a transponder. An uplink DAC 73 sets the RF power level required for an uplink transmission of CW for a response from a backscatter transponder. Selection between the low-pass filtered uplink and downlink levels is handled by the Attn_Sel signal through an SPDT switch. Another SPDT switch passes the selected DAC level or a preset reference level as the VCTL Attn signal, which is utilized to limit the dynamic range of the voltage variable attenuator 66 . Both the downlink and uplink power levels are calibrated independently to provide 15 dB of dynamic range in 1 dB steps. [0071] Each protocol requiring a downlink transmission from the interrogator has an independent memory location in the controlling device 43 to store the static power level for the respective configuration. The same is true for each protocol that requires an uplink transmission. The controller 43 controls the sequence of the downlink and uplink transmissions based on the protocol configuration and discrete inputs from the processor 100 . The integrated power amplifier 68 is selected to provide the maximum desired output at the RF port while maintaining a high degree of linearity. The RF switch is utilized to provide the necessary OFF isolation when the active receiver is enabled. Transmitter Signal Processing [0072] A low-pass filter 74 , coupler-isolator-coupler configuration 76 , 77 , 78 completes the transmitter chain. The low-pass filter 74 attenuates harmonic emissions. The first RF coupler 76 provides the feedback necessary for closed-loop control. The coupled signal from the coupler 76 is fed into a 4-bit digital step attenuator 97 that provides 15 dB of dynamic range in 1 dB steps. By providing the dynamic range in the power control feedback path, the closed loop control of downlink and uplink RF output power is simplified and accuracy of the transmitted power level is improved. [0073] The 15 dB feedback attenuation range coincides with the 15 dB dynamic range of the transmitter to set the respective power level for the downlink or uplink transmission. The feedback attenuator is set such that the attenuation level set on the uplink or downlink transmission, plus the level set on the digital step attenuator 97 in the feedback loop, always add up to 15 dB. That minimizes the dynamic range of the signal after the digital step attenuator 97 to the highest DOM level required by the supported protocols. The attenuator 97 output is fed into a logarithmic RF power detector 98 that converts the RF signal into a voltage equivalent that corresponds to the RF level detected. [0074] In essence, the modulating signal is reconstructed at voltage levels that represent the peak value transmitted for a digital “high” on the downlink, a digital “low” representing the DOM level, or the CW level on the uplink. The voltage levels for a digital “high” and a CW condition remain virtually the same for the entire 15 dB dynamic range for transmit power due to the corresponding level set on the digital attenuator in the feedback loop. The voltage level for a digital low corresponds to the respective DOM level set for the protocol being transmitted. [0075] In normal operation, the signal representing the detected RF level is adjusted for temperature drifts seen by the detector circuit and scaled for input into an analog-to-digital converter (ADC) 99 . The output of the ADC 99 is fed into the controlling device 43 on the transceiver 30 that provides control of peak power, CW power, and the DOM, by utilizing closed loop algorithms. The isolator 77 provides isolation of the transmitter from the Tx port and the antenna port. The final RF coupler 78 provides the receive path from the antenna port to the Rx port. Receiver [0076] The receiver portion of the transceiver 30 , FIG. 4 , accepts and processes the backscatter and active responses of the respective transponders. The RF receive chain begins with a band pass filter 82 that includes a pre-attenuator and a post-attenuator followed by a gain block. The filter 82 establishes the pass band for the backscatter receiver and encompasses the pre-selector for the active receiver as well. The sensitivity attenuator 84 and gain block establishes the RF dynamic range of the receiver. [0077] The sensitivity attenuator 84 is also adjustable based on the protocol selected, to provide the capability to independently adjust and tune the sensitivities of the respective protocols. The sensitivity attenuator 84 is a 4-bit digital step attenuator that provides 15 dB of dynamic range in 1 dB steps. This attenuator provides the capability to vary the sensitivity level of the interrogator for each protocol. From a calibration standpoint, the sensitivity level of each protocol would be set such that they are approximately the same provided they meet established limits. For instance, if the maximum sensitivity of one protocol is −66 dBm and the maximum sensitivity of another protocol is −63 dBm, both can be calibrated to −62 dBm assuming the limit is −60 dBm. Adjusting for the active and backscatter receive sensitivities aids in the alignment of the capture zone when operating in a multiple protocol environment. [0078] The select block 86 provides the capability to select between two different receive paths, a backscatter receive path (along elements 92 , 94 , 96 ) and an active receive path (along elements 88 , 90 ), based on the protocol selected. An RF switch is utilized to separate the backscatter receive path and the active receive path. The processor 100 controls the state of the switch through the controlling device 43 on the transceiver 30 . [0079] The backscatter receive path includes the backscatter receiver 92 , baseband processing 94 , and zero crossing detectors 96 . The backscatter receiver 92 includes a 0 degree power divider, a 90 degree hybrid, isolators, and mixers. The 0 degree power divider allows for an I & Q (In-phase & Quadrature) configuration that has two signals, one that is in-phase and one that is 90 degrees out of phase. To produce the I & Q channels, the LO 48 output is fed through the 90 degree hybrid. The receive and LO paths are then fed through isolators in their respective paths to provide the RF and LO inputs to mixers for direct conversion to base band for processing by the baseband processing 94 . The isolators in the 0 degree path are required to isolate the active receiver from the transmitter LO and provide a good voltage standing wave ratio (VSWR) to the hybrid coupler, which results in good phase and amplitude balance. [0080] The isolators in the 90-degree path are also required to provide a good VSWR to the hybrid coupler. In the baseband processing 94 , filter and amplifier paths are provided for high, medium, and low speed I & Q signals to allow for the differing bandwidth requirements of the respective protocols. Zero-crossing detectors 96 convert the signals into a form required by the controlling device on the transceiver for additional processing. [0081] The active receive path includes an active receiver 88 and a threshold detector 90 . The active receiver 88 includes a band pass filter, gain block and attenuation, logarithmic amplifier. The band pass filter establishes the pass band and noise bandwidth for the active receiver. The gain block and attenuation combination establishes the dynamic range of the receiver in conjunction with a logarithmic amplifier that converts a received Amplitude Shift Keyed (ASK) transmission to base band. The base band processing, which is part of the active receiver 88 , does a peak detect and generates an automatic threshold to provide greater receiver dynamic range and signal level discrimination. A static adjustable range adjust threshold sets the initial threshold level for the threshold detector 90 . The threshold level is selected so that the receiver is not affected by noise by setting the initial threshold level for the threshold detector 90 above the receiver's noise floor level. The threshold level also aids in the alignment of the capture zone. In a given application, the capture zone can be reduced from its maximum by increasing this threshold level. Dynamic Adjustments [0082] The controlling device 43 on the transceiver 30 provides the necessary functionality and control for factory calibration, initialization, source selection, DOM (closed-loop), RF power (closed-loop), transmitting and receiving, and built-in-test. The preferred embodiment of the controlling device 43 is a Field Programmable Gate Array and the associated support circuitry required to provide the functionality described. The capability to factory calibrate is provided for the synthesizer reference clock, depth of modulation, and RF power. Calibration of the reference clock is provided through a digitally controlled solid-state potentiometer that feeds into the voltage controlled frequency adjust port of the reference oscillator. The oscillator is factory calibrated to a frequency standard that provides the LO for the measuring device. The digitally controlled potentiometer contains on-board non-volatile memory to store the calibrated setting. [0083] Depth of modulation calibration is provided for the levels required by the supported protocols. The levels are 20 dB (IT2000), 30 dB (Title 21) and 35 dB (EGO, SEGO, IAG), which are stored in non-volatile memory during factory calibration. The respective levels are retrieved from the controller's 43 memory and loaded into the DOM DAC 70 based upon the protocol that is selected and what the DOM level was set to for the respective protocol during the initialization of the transceiver 30 . [0084] RF power is calibrated in 1 dB steps over the 15 dB dynamic range for both synthesized sources 33 , 45 . Each level is stored in non-volatile memory during factory calibration. The respective levels are retrieved from memory and loaded into the downlink and uplink attenuation DACs 72 based upon the protocol that is selected and what the power level was set to for the respective protocol during the initialization of the transceiver 30 . [0085] The initialization process sets the frequency for the synthesized sources S 1 , S 2 , as well as for the downlink attenuation, uplink attenuation, source designation, duty cycle, base band range adjust and sensitivity adjust levels for the respective protocols. A clock, serial data line, and a load signal are provided by the processor 100 to load the synthesizers 33 , 45 . A serial UART is used to pass attenuation, source designation, range and sensitivity adjust from the processor 100 to the transceiver 30 . [0086] Source selection and transmit control is provided by the processor 100 via configuration discretes that designate the selected protocol in conjunction with a discrete that indicates whether downlink or uplink is active and a discrete for on/off control. Based upon the active configuration and the parameters set during initialization, the appropriate attenuation levels are set from the calibrated values in memory for the designated source. Acknowledge discretes are provided by the transceiver 30 to facilitate sequencing. The sequence is dictated by the respective protocol and is designed to maximize efficiency. In addition, an acknowledge message can be sent to the tag to activate audio/visual responses as well as put the transponder to sleep for a period of time defined in the acknowledgement message. It is desirable to put a tag to sleep so that it doesn't continue to respond, such as if the vehicle is stuck in a lane, and so that the interrogator can communicate with other tags. [0087] The RF power control for the downlink and uplink RF output power is a closed loop system to provide stable power across frequency and temperature, and stable DOM, independent of protocol. In accordance with the preferred embodiment, the closed loop for DOM control includes the controller 43 (which includes the controlling algorithm), DOM controller 60 , MOD/CW 56 , RF AMP 65 , filter 74 , coupler 76 , attenuator 97 , sensor 98 , ADC 99 , and back to controller 43 . The detected coupled output after the power amplifier provides the feedback path to the Field Programmable Gate Array 43 . The Field Programmable Gate Array 43 contains closed loop algorithms for controlling both the CW uplink power levels and the peak power levels for the modulated downlink. The closed loop power control algorithm samples the peak power level in the feedback path and compares it to a factory calibrated power level reference. The control voltage (VCTL Attn) is adjusted through the DL/UL DAC & Power Control 72 to zero out the error from the comparison. [0088] The DOM control is also a closed loop system to provide stable DOM across frequency and temperature, including for the RF AM DOM. Here, the closed loop for the peak RF power control includes the controller 43 (which includes the controlling algorithm), power controller 72 , RF AMP 65 , filter 74 , coupler 76 , attenuator 97 , sensor 98 , ADC 99 , and back to the controller 43 . The controller 43 includes a detected coupled output after a power amplifier that provides the feedback path to the Field Programmable Gate Array 43 . The Field Programmable Gate Array 43 contains closed loop algorithms for controlling the DOM for the modulated downlink. The closed loop DOM control algorithm samples the minimum power level in the feedback path and compares it to a factory calibrated DOM reference for the respective protocol. The level within the Filter Mod signal that indicates the transmission of a “low” bit, or the DOM (depth of modulation) level, will be adjusted through the DOM DAC & Modulation Control 60 to zero out the error from the comparison. [0089] Receive control is provided by the processor 100 via configuration discretes that designate the selected protocol. The microprocessor 102 generates the discretes, which in the preferred embodiment are five signals having a total of 32 unique modes. For instance, a discrete signal could be 00011, which signifies an EGO protocol and its specific parameters for operation. The discretes are sent to the controller 43 , and the interrogator 12 configures itself to communicate with the selected tag by setting the appropriate power level, bit rates, backscatter path, and the like. Based upon the active configuration and the parameters set during initialization, the appropriate receiver is activated and the sensitivity adjust level is set from the calibrated values in memory for the respective protocol. [0090] The processor 100 contains all of the necessary circuitry to perform or control the various interrogator functions. It contains a microprocessor 102 for running application code which controls manipulating and passing the decoded tag data to the host, communications interfacing, interrupt handling, synchronization, I/O sensing, I/O control and transceiver control. The self test techniques (discussed below) for the system utilizing the loop-back technique and the test tag technique are also controlled by the processor 100 through the configuration control discretes. Dynamic RF Power Adjustment [0091] The ability to adjust the level of RF power transmitted serves multiple purposes. Independent of transponder type and external interfering signals, capture zones rely upon the RF power transmitted and the gain of the transmit/receive antenna. The multiple protocols supported by the interrogator translates to the specific requirements of the respective transponders. They can be passive or active, battery or beam powered, with additional variables that are dictated by the physics of the transponder. These variables include transponder receive sensitivity, turn on threshold, antenna cross section and conversion loss. To support these variables, the RF power of the interrogator must be adjustable to levels stored in memory for each protocol such that the appropriate levels are set when the respective protocol is selected. Dynamic Depth of Modulation (DOM) Adjustment [0092] The ability to select the DOM level of the transmitted downlink serves major purposes. Independent of transponder type and external interfering signals, the transponders receiver dynamic range relies upon the DOM transmitted during the downlink. The multiple protocols supported by the interrogator translate to the specific requirements of the respective transponders. Their base band processing can be AC or DC coupled, with additional variables that are dictated by the physics of the transponder. To support these variables, the downlink DOM from the interrogator must be selectable to levels stored in memory for each protocol such that the appropriate DOM is set when the respective protocol is selected. Dynamic Modulation Duty Cycle Adjustment [0093] The ability to select the duty cycle for the base band downlink modulation provides the flexibility to compensate for finite non-linearity in the modulation path and the capability to optimize the duty cycle to the respective transponder requirements. [0094] A synchronous clock provides the capability to lengthen a “high” bit on the modulated signal from the encoder to increase the duty cycle of the signal provided to the DOM DAC & Modulation Control 60 . Conversely, lengthening a “low” bit on the modulated signal from the encoder decreases the duty cycle of the signal provided to the DOM DAC & Modulation Control 60 . To support this capability, the duty cycle value is retrieved from the memory of the controller 43 that was set during the initialization process for each protocol such that the appropriate duty cycle is set when the respective protocol is selected. [0095] The independent adjustment of the duty cycle or pulse width aids in the tuning of the modulated signal to the transponder requirements and in the derivation of transponder sensitivity to variations of duty cycle. For example, the Title 21 specification does not specify duty cycle or the rise and fall times for the reader to transponder communication protocol. Consequently, manufacturers who build transponders that meet the Title 21 specification produce transponders with characteristics that differ with respect to these parameters. Dynamic Frequency Selection [0096] Frequency selection is dynamic in the sense that there are separate downlink and uplink sources 33 , 45 that are fixed to specific frequencies. In a typical single mode application with multiple interrogators, the downlink (or modulated) frequency is set to the same frequency on all of the interrogators and the uplink (or CW) frequency is set to specific frequencies that are dependent on the respective protocol. Higher data rate protocols require more separation between uplink frequencies but allow for frequency reuse across multiple lanes, i.e., use the same frequency in multiple lanes, without interference. Lower data rate protocols require less separation between uplink frequencies, however, frequency reuse becomes much more of an issue. [0097] The interrogator 12 will typically operate on a single downlink frequency, so that only a single downlink synthesizer 45 is needed. However, the uplink signals can be sent on more than one frequency. Since each of the synthesizers 33 , 45 operate at a fixed frequency, it would be time consuming to switch the internal frequency for that synthesizer. Accordingly, two synthesizers can be used to send uplink signals. The uplink synthesizer 33 can send an uplink signal on a first frequency, and the downlink/uplink synthesizer 45 can send an uplink signal on a second frequency. It should be recognized, however, that the invention can be implemented using more than one downlink frequency, and more or fewer uplink frequencies. [0098] Thus, when a high speed protocol and a low speed protocol are integrated into a single multiple interrogator application, channel limitations arise due to bandwidth limitations imposed by radio regulatory authorities. The system allows for this by the use of the step-lock arrangement and the capability to setup the interrogator to allow the downlink source to be utilized as the uplink source for the low speed protocol while the high speed protocol utilizes the dedicated uplink source. This allows for the high speed and low speed protocols to be channelized independently within the regulatory bandwidth limitations and provides flexibility for the multiple protocol, multiple interrogator application. Self-Test Operation [0099] The check tag system of the prior art is not well suited for use with then multiple protocols of the present invention. The multiple check tags used to verify the respective signal paths place additional time constraints and inefficiencies on the system. Instead, turning to FIG. 10 , the system includes a self-test operation having the additional capability of synchronizing the self-test cycle within a cluster of interrogators 22 . Backscatter operation requires that the interrogator transmit uplink signals as a continuous wave (CW) in order to receive the response from a backscatter transponder. Since the receiver is active during the transmission of the uplink CW, it is possible for the backscatter receivers to detect and process the downlink signal, which is an amplitude modulated (AM) carrier. [0100] The serial bit stream originating from the processor 100 via the encoder 104 is looped back to the processor 100 via the decoder 106 as indicated by the dotted lines. The loop starts at the encoder 104 , and proceeds to the controller 43 to the DOM DAC & Modulation Control 60 , to the MOD/CW 56 , to the AMP 65 , to the filter 74 , to the coupler 76 , to the isolation 77 , to the coupler 78 , to the filter 82 , to the sensitivity attenuator 84 , to the select 86 . At the select 86 , the Rx Select signal determines the path that the serial bit stream will take. One state will take it through the backscatter receiver 92 chain while the other state will take it through the active receiver 88 chain. [0101] As a result of the loop, the processor 100 is able to verify whether the serial bit stream through the decoder 106 matches the bit stream sent via the encoder 104 . If the serial bit stream sent by the encoder 104 matches the bit stream received by the decoder 106 , the microprocessor 102 indicates that all of the elements along the test path are operating properly. However, even if the bit stream is off by a single digit, the microprocessor 102 will indicate that the system is not operating properly. Preferably, the test bit stream is between 4 and 16 bits in length, so that the test is fast, though a test could also have a bit stream length of an actual message, i.e., 256 bits. [0102] Note that the active receiver 88 is tested as well with this process, if it is active during the transmission of the downlink AM carrier, even though that is not the normal mode of operation and only viable from a test standpoint. The serial bit stream can be a simple pattern and very short in duration compared to the response from even the highest baud rate check tag. This method provides the means to confidence test the downlink source, the RF transmitter chain, the active receiver and the backscatter receivers. The uplink source can be tested in the same manner by simply modulating what would normally be the CW source. [0103] However, the loop shown in FIG. 10 does not provide a confidence test of any components after the Tx/Rx coupler 78 , i.e., the antenna, or the RF cable. To do so, the system uses the system shown in FIG. 11 . The test tag 110 is a switching device connected to a coupling antenna that is mounted near the system antenna. The switching device is controlled by the processor 100 to produce a backscatter response when coupled to the uplink CW transmitted from the system antenna. The serial bit stream for the test tag 110 can be the same simple pattern utilized for the loop-back mode of FIG. 10 , or it can be unique. [0104] The system of FIG. 11 provides the means to confidence test the uplink source, the RF transmitter chain, the backscatter receivers as well as the antenna and coaxial cable. A full response can be simulated for backscatter tags to facilitate more in-depth testing when it is warranted. A simplified alternative to this method is shown in FIG. 12 , where the transmitter is coupled directly to the test tag 110 . The self-test system can be used with any transmitter, receiver or transceiver, and need not be used with a step-locking system or an interrogator. In step-lock, the interrogator treats the test sequence as another protocol so that the test occurs in the same time frame. Thus, in the embodiment of FIG. 3( a ) for instance, the test sequence would occur after the processing time of Tag Protocol 2 and prior to another Sync Signal. Illustrations [0105] FIGS. 13-21 illustrate various embodiments of the system. In each of these embodiments, the system is designed to cover an unlimited number of lanes, though preferably the system is used with up to about eleven lanes of traffic, plus four shoulder lanes. The system accommodates two primary protocols. The first protocol is for a tag sold under the trade name EGO. The first protocol has uplink frequencies that should not be shared since it could result in frequency instability. In addition, there must be at least 500 kHz clear spectrum around each uplink channel. The downlink channels can share the same frequency, or they can be on different frequencies. The downlink spectrum from modulation will interfere with uplink and must be kept out of the uplink receive bandwidth. [0106] The second protocol is for an IT2000 tag. The second protocol has tags that wake up in three stages; RF power gets them to stage one, detection of a downlink signal gets them to stage two, and stage three is the tag response to a read request. Uplink frequencies can be shared, and multiple interrogators can use the same channel on the uplink. There must be at least +/−6 MHz of clear spectrum around each uplink channel. Downlink channels can share the same frequency, or they can be on different frequencies. Downlink spectrum from modulation (either the first or second protocols) will interfere with the uplink signal and must be kept out of uplink spectrum. [0107] For the interrogators, the downlink and uplink frequencies cannot be changed during operation, but remain fixed at their configuration frequencies. All interrogators are step-locked to each other so that they are synchronous in time. The timing is controlled by the TDM signal and internal CAM files. Step-locking keeps the interrogators from interfering with each other, and eliminates the need for shutting interrogators down during different time slots. Single Tag Protocol [0108] In the embodiment of FIGS. 13-18 , a system is provided for tags employing a single signaling protocol, which is the IT2000 protocol in this illustration. As best shown in the embodiment of FIG. 15 , there are several different commands of different lengths that have to be exchanged between the interrogator 12 and the tag. Since the commands are different lengths, the interrogator 12 adds dead time to the start of the shorter commands to ensure that all downlinks end at the same time. [0109] This mode utilizes a frequency plan with the downlink at 918.75 and the uplinks at 903 MHz and 912.25 MHz and 921.5 MHz. The downlink and uplink are locked so that downlink signals do not interfere with uplink signals. However, the interrogators do not have to be command locked. They are able to independently issue commands. That means that one interrogator may issue a read request while an interrogator in another lane is issuing a write request. Only the uplink and downlink are synchronized. Since the downlinks happen at the same time, the uplinks do not occur at the same time as the downlinks, thereby freeing up the entire spectrum for each of the uplink and downlink transmissions. [0110] The downlink frequency plan is shown in FIG. 13 . In this configuration, all downlinks are operating on the same frequency. FIG. 14 show the uplink frequency plan, where the uplinks use a three frequency reuse plan, namely 921.5 MHz, 912.25 MHz, and 903 MHz. As shown, the ranges for each of the three different uplink frequencies do not overlap with one another, so that the frequencies are spaced across the lanes to reduce the interference between the interrogators. At the same time, each frequency is present in each of the three lanes, so that the interrogator for each lane can receive information on any of the uplink frequencies. The oval patterns are created by positioning an interrogator antenna 18 at the top of the oval. [0111] In operation, upon power up or after a reset has occurred, the interrogator is initialized with the parameters required for the respective application, such as the downlink and uplink frequencies. Protocol specific parameters are also set during initialization, including downlink and uplink power level, DOM level, sensitivity attenuation, range adjust, as well as source, receiver and transmitter assignments for the specific application protocol. Those parameters correspond to the five bit configuration assigned in the processor 100 to the protocol. [0112] Thus, for IT2000, a configuration of 00010 from the processor 100 signals the transceiver 30 to retrieve the IT2000 specific parameters from the controller 43 memory for an impending communication sequence. The transceiver acknowledges the processor 100 , and indicates that it has received and set the appropriate parameters for the specific configuration. If it is a single protocol application, and the configuration does not change, occurs once since the transceiver 30 will then be set to the appropriate configuration from that time forward. [0113] The processor 30 turns on the transceiver 30 transmitter chain and an IT2000 command is encoded and transmitted on the downlink source at a specific power and DOM level initialized for the IT2000 tags. The modulation signal travels through the high-speed transmit filter path set during initialization. Shortly after the downlink transmission is complete, the control signal changes state to turn the downlink source off. This also turns the uplink CW source on at a specific power level and enables the respective receive parameters that were set during initialization. If an IT2000 transponder response is received and decoded through the high-speed backscatter path, it is processed at the end of the uplink CW transmission and the sequence repeats. All timing is tightly controlled to accommodate the step-lock techniques. If step-lock is enabled, the sequences are keyed from the reception of the synchronization signal. [0114] Turning to FIG. 15 , the timing of the various uplinks and downlinks is shown. The timing gives an overall time per slot of at least about 3.5 ms, though the timing could be reduced to about just over 2 ms (the time it takes to complete the longest transaction, if no processing time was required. At 3.5 ms, the entire transaction takes a minimum of about 21 ms. In 3.5 ms a vehicle travels 0.51 feet (100 mph), and in 21 ms a vehicle travels 3.08 feet. Accordingly, the tag has the opportunity to cycle through the protocol several times prior to vehicle traveling a distance beyond the range required to uplink and downlink signals. For a 10 foot read zone, the tag could complete approximately 3.3 entire transactions. [0115] As shown in FIG. 15 , various downlink and uplink communication protocols are utilized by the interrogator. The commands are defined in the following Table 1. Thus, for instance, pursuant to the first command, Read Page 7, the interrogator sends a read request to the tag on the downlink, and the tag sends a read response on the uplink. [0000] TABLE 1 Protocol Commands Command Downlink Uplink Read Page 7 Read Request Read Response Read Page 9 Read Request with ID Read Response Random # Request Random # Request Random # Response Write Page 9 Write Request with ID Write Response Write Page 10 Write Request with ID Write Response Gen Ack General Acknowledgement No Response [0116] In the example of FIG. 15 , a different interrogator 12 transmits each of the commands. Accordingly, the duration of the uplink, downlink, uplink dead time, downlink dead time, and interrogator processing time differs for each of the various commands. For instance, the Write Page 9 and Write Page 10 commands have long downlink periods since information is being written. However, the signals are step-locked, so that all of the downlinks end at the same time and the uplinks start at the same time. Thus, there is no interference between the uplink and downlink transmissions. Two Signaling Protocols [0117] In the embodiment of FIGS. 16-18 , a system is provided for tags employing two signaling protocols, which are the IT2000 and EGO protocols in this illustration. FIGS. 16-17 show the spectrum requirements for the frequency plan, with FIG. 16 showing the downlink plan and FIG. 17 showing the uplink plan. The plan requires that the downlink and uplink be synchronized for all interrogators. That means that during a certain time period all interrogators are transmitting their downlink signals. During the next time period the interrogators are transmitting their uplink signals. During these time periods the interrogators may be supporting either of the two protocols. It is not required for the interrogators to be synchronized for the protocols, only that the downlink or uplink signals be synchronized. [0118] During the downlink cycle, all of the interrogators transmit at 918.75 MHz. During the uplink cycle, the odd IT2000 interrogators transmit at 921.5 MHz, and the even interrogators transmit at 903 MHz. The EGO uplinks are spaced between 910 MHz and 915.5 MHz. The interrogators have to be either IT2000 or EGO interrogators. The means that if lane coverage requires 7 coverage areas, this implementation would require 14 separate interrogators. Or if the interrogators are frequency agile, then the interrogator could switch between the required IT2000 uplink frequency and the required EGO uplink frequency depending on the protocol being transmitted at that time. [0119] Adding additional interrogators can cover additional lanes. The number of EGO uplink channels that can be supported between 910 MHz and 915.5 MHz limits the number of lanes. If the spacing between interrogators can be reduced to 500 kHz, the number of EGO interrogators supported would be 12. If additional EGO interrogators are needed then all the IT2000 uplinks could be moved to 903 MHz and room for an additional 12 EGO interrogators would be available between 915.5 MHz and 921.5 MHz. This configuration would support 24 EGO interrogators. [0120] In operation, upon power up or after a reset has occurred, the interrogator is initialized with the parameters required for the respective application, such as the downlink and uplink frequencies. Protocol specific parameters are also set during initialization, including downlink and uplink power level, DOM level, sensitivity attenuation, range adjust, as well as source, receiver and transmitter assignments for the specific application protocols. Those parameters correspond to the five bit configuration assigned to the respective protocol. [0121] A configuration of 00010 from the processor 100 signals the transceiver 30 to retrieve the IT2000 parameters from memory for an impending communication sequence. The transceiver acknowledges the processor 100 , indicating that it has received and set the appropriate parameters for the IT2000 protocol. The processor 30 then turns on the transceiver 30 transmitter chain and an IT2000 command is encoded and transmitted on the downlink source at a specific power and DOM level initialized for the IT2000 protocol. The modulation signal travels through the high-speed transmit filter path set during initialization. [0122] Shortly after the downlink transmission is complete, the control signal changes states to turn the downlink source off. That also turns the uplink CW source on at a specific power level and enables the respective receive parameters that were initialized for the IT2000 protocol. If an IT2000 transponder response is received and decoded through the high-speed backscatter path, it is processed at the end of the uplink CW transmission. [0123] A configuration of 00011 from the processor 100 then signals the transceiver 30 to retrieve the EGO parameters from memory for an impending communication sequence. The transceiver acknowledges the processor 100 , thereby indicating it has received and set the appropriate parameters for the EGO protocol. The processor 30 turns on the transceiver 30 transmitter chain and an EGO command is encoded and transmitted on the downlink source at a specific power and DOM level initialized for the EGO protocol. The modulation signal travels through the low-speed transmit filter path set during initialization. [0124] Shortly after the downlink transmission is complete, the control signal will change states to turn the downlink source off. That also turns the uplink CW source on at a specific power level and enables the respective receive parameters that were initialized for the EGO protocol. If an EGO transponder response is received and decoded through the low-speed backscatter path, it is processed at the end of the uplink CW transmission and the entire sequence will repeat. All timing is tightly controlled to accommodate the step-lock techniques. If step-lock is enabled, as in FIG. 3( a ), the sequences are keyed from the reception of the synchronization signal. The IT2000 protocol is Tag Protocol 1 and the EGO protocol is Tag Protocol 2. [0125] FIG. 16 shows how the downlink frequency is used to cover a system that has three lanes with coverage for the shoulders of each of the outside lanes, and FIG. 17 shows the layout for the uplink frequencies. In the figures, the circles represent the coverage achieved over an area of the road surface. The numbers in the circles represent the individual interrogators, with the number on the left for the IT2000 interrogator and the number on the right for the EGO interrogator. The numbers assigned to each half-circle represent the frequency being used by that particular interrogator and matches up with a frequency on the left. The IT2000 interrogators alternate between frequencies at 903 MHz and 921.5 MHz. The IT2000 protocol allows the frequencies to be shared without the interrogators significantly interfering with each other. The EGO interrogators use the frequencies between 909.75 MHz and 915.75 MHz. Since each EGO interrogator requires a unique frequency for its uplink, the EGO frequencies are not shared. [0126] FIG. 18 displays the timing required for the commands used by EGO and IT2000 tags. The first line is the EGO read command, which is a group select for the downlink and a work data (tag ID) on the uplink. This is the only EGO command required for this illustration. Upon receiving this command, the EGO tag reports back its ID. The rest of the commands are the IT2000 commands listed in Table 1 above, which are completed in the sequence shown. [0127] The critical timing location is the transition between the uplink and downlink. That transition needs to occur at nearly the same time for all of the interrogators. If an interrogator stays in a downlink mode for too long, it could interfere with the uplink signals. The dead time for both the uplink and downlink is the time that no commands are being sent or received by the interrogator. The interrogators generally use the dead time to align their downlink and uplink signals. The processing time is the time required by the interrogator to process commands received by the tag. [0128] The interrogator alternates between an EGO Read command and an IT2000 Read Page 7 command until it receives a tag response. An EGO tag response is processed during the uplink time and then is followed by an IT2000 Read Page 7 Command. The rest of the IT2000 commands follow an IT2000 tag response to the Read Page 7 Command. [0129] By setting up the system the present way, an interrogator at one lane that is processing an IT2000 tag does not force the rest of the interrogators in the other lanes to wait until that tag is finished. The rest of the interrogators can continue to alternate between the IT2000 and EGO reads. The system dramatically increases the time required to process an IT2000 command. The current IT2000 transaction takes around 14 ms plus some additional transaction time. The minimum amount of time required for this process would be about 40 ms. If the interrogator misses any commands and the missed commands have to be repeated, the time would increase by about 7 ms per repeated command. At 100 mph, a vehicle travels about 6 feet in 40 ms, which is a significant portion of the capture zone. [0130] FIGS. 19-21 are another illustration of the system used with multiple backscatter protocols, namely EGO and IT2000. In the present illustration, the interrogators incorporate the capability of using either source 33 , 45 as an LO in the receiver. This allows interrogators to use different frequencies for the EGO and IT2000 uplinks. Only one source needs to be modulated since the EGO and IT2000 downlinks can be on the same frequency. All of the interrogators are step-locked in time so that they are all performing the same operation at the same time. This ensures that no interrogators are transmitting while another interrogator is trying to receiving. [0131] In addition, a frame consists of an IT2000 command set and an EGO command set. During the IT2000 command set the entire IT2000 command sequence is sent. Therefore, during one frame an IT2000 tag can be read, written to, and generally acknowledged off before the command set returns to the EGO commands. The frame is approximately 14 ms in duration covering both the EGO and IT2000 command set. In order to reduce the time required to complete the IT2000 transaction, the IT2000 transaction has been reduced to a single read, single write and three general acknowledgements. [0132] FIG. 19 shows the spectrum requirements for the frequency plan. The blocks represent the frequency location and bandwidth required for each signal. The IT2000 signals are wider because of IT2000's faster data rate requiring more spectrum. The figure shows that the EGO signals and the IT2000 downlink signal share the same center frequency. These signals use one of the sources in the interrogator while the other source is used by the IT2000 uplink signals. The numbers in the blocks represent the different interrogators used to cover the lanes. [0133] The IT2000 downlink and EGO uplink and downlink frequencies are spaced across the 909.75 to 921.75 MHz band. The spacing requirement is determined by the selectivity of the EGO receive filters. The narrower the EGO uplink filters, the tighter the frequencies can be spaced and the greater the number of lanes that can be supported. If the spacing can be reduced to 500 kHz between channels, this setup supports 13 interrogators. An additional two EGO interrogators could be added at 903 and 921.5, by sharing the uplink signals used by the IT2000 channels. This would give a total of 15 interrogators, or the ability to support 6 lanes and 4 shoulders. [0134] FIG. 19 also shows a frequency plan for a 3-lane system for the IT2000 downlink and the EGO interrogators. For this implementation, each interrogator is on a different frequency to eliminate the frequency reuse issue associated with the EGO uplink. Lane discrimination is accomplished by setting the correct power levels from the interrogators. To get more lane coverage the power is increased to reduce lane coverage the power is decreased. [0135] As shown in FIG. 20 , the IT2000 uplink signals are at 903, 912.25, and 921.5. The minimum spacing for IT2000 uplink is determined by the selectivity of the IT2000 receive filters. These filters need about 6 MHz of spacing between channels. However, unlike the EGO uplink channels, the IT2000 uplink frequencies can be reused so that several interrogators can use the same channel. [0136] FIG. 20 also shows the frequency plan for a 3-lane system for the IT2000 uplink interrogators. For this implementation, the IT2000 uplinks share three center frequencies: 903, 912.25 and 921.5. Since the IT2000 uplink channels can reuse the same frequency, those frequencies are shared over several interrogators. The figure shows one method of setting up the lanes to reduce the co-channel interference by separating interrogators that use the same frequency as far apart physically as can be accomplished. [0137] FIG. 21 shows the timing associated with step-locking all of the interrogators together. For that system, all interrogators are locked together on the same timing. Locking the signals together ensures that no interrogator is performing downlink modulation while another interrogator is attempting to receive an uplink signal. If that were to happen, the downlink modulation could interfere with the uplink signal and block its reception. [0138] The timing plan assumes that the IT2000 commands are reduced to a single read, a single write, and three general acknowledgements (Gen Ack). The system transmits the read request until it receives a read response and then the rest of the read, write, and gen ack commands are completed. In this method, the system completes the entire read, write, and gen ack command set each cycle. The cycle time for these commands is around 14 ms. At 100 mph a vehicle travels about 2 feet. If the read area is 10 feet deep then the system should get between 4 and 5 reads depending on when in the cycle the tag enters the capture zone. [0139] The foregoing description and drawings should be considered as illustrative only of the principles of the invention. The invention may be configured in a variety of ways and is not intended to be limited by the preferred embodiment. Numerous applications of the invention will readily occur to those skilled in the art. Therefore, it is not desired to limit the invention to the specific examples disclosed or the exact construction and operation shown and described. Rather, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

A multi-protocol RFID interrogating system employs a synchronization technique (step-lock) for a backscatter RFID system that allows simultaneous operation of closely spaced interrogators. The multi-protocol RFID interrogating system can communicate with backscatter transponders having different output protocols and with active transponders including: Title 21 compliant RFID backscatter transponders; IT2000 RFID backscatter transponders that provide an extended mode capability beyond Title 21; EGO™ RFID backscatter transponders, SEGO™ RFID backscatter transponders; ATA, ISO, ANSI AAR compliant RFID backscatter transponders; and IAG compliant active technology transponders. The system implements a step-lock operation, whereby adjacent interrogators are synchronized to ensure that all downlinks operate within the same time frame and all uplinks operate within the same time frame, to eliminate downlink on uplink interference.

TECHNICAL FIELD OF THE INVENTION The present invention provides a sterilizing fog, characterized by droplet size range, vapor density range, sterilant concentration range and sterilant concentration within the droplets. Specifically, the inventive fog is achieved by an apparatus combining pressure, temperature and acoustics to form a super-charged ozoneated water and an apparatus that creates small micro droplets which form a highly concentrated sterilizing fog. Specific sterilants used are ozone, chlorine and chlorous acid generating compositions such as sodium hypochlorite. BACKGROUND OF THE INVENTION Food processing and food safety has increasingly relied upon techniques to remove or eliminate harmful microbial organisms from the surfaces of food products. Harmful bacterial products have been found on meat food products, such as salmonella on poultry and E. Coli H057 on various red meats. Various techniques have been developed to test for the presence of such harmful organisms but such tests, inherently, can only sample random surfaces and rely on probabilities to determine of all of the surface area of food products has either been free of such harmful organisms or effectively decontaminated. There are many broad-spectrum sterilizing agents that are strong oxidants, such as chlorine, hypochlorite (bleach), hydrogen peroxide, and ozone or O 3 . Although chlorine is the most common sterilizing agent in the world, ozone is commonly used to sterilize hot tubs and other public swimming pools. In addition, poultry and other meat-processing that historically has relied solely on chlorine, now frequently baths chickens in water containing ozone. However, in order for the ozone, or chlorine or any other sterilant in water to be effective, the sterilizing agent is present in a sufficient concentration within water and in contact with the organisms (and the chicken) for a sufficient period of time (inversely related to concentration) to allow the oxidizing agent to contact and kill microorganisms. It is difficult to achieve such high concentrations in an aqueous liquid. In a gaseous form most sterilizing agents are rather hazardous and difficult to control exposure time. Ozone decays in a gaseous form far too quickly to be useful for food processing. Thus, water is the preferred media for transporting ozone, chlorine, and hypochlorite to a contaminated site for oxidative anti-microbial activity. Unfortunately, the realities of food processing are such that many food products cannot be immersed in a liquid bath (e.g., most fresh meat products and even some dry products like grains) although some moisture is allowed contact. In those instances where water immersion is not permitted, spray systems have been developed to spray a water-laden with oxidizing agent. However, spray systems do not provide a uniform coverage of the product and can utilize large amounts of water. Accordingly, spray systems employing larger droplets of water containing ozone, chlorine or hypochlorite have not been effective because of a droplet size that is too large to effect food surface penetration of irregularities. Moreover, the lower concentrations of sterilizing agents achievable in such spray systems, coupled with short exposure times, do not provide for effective oxidizing potentials and anti-microbial activity to be sufficiently effective as a decontaminating process. This is especially true of chlorine and hypochlorite that require long exposure times. A further issue is that liquid sterilization systems or spray systems with large droplets are unable to penetrate micro-cavities on irregular surfaces of food products, such as meats (e.g., poultry or bovine). Water surface tension prevents the large drops and liquid baths from penetrating these regions and the bacteria present in micro-cavities remains undisturbed (FIG. 1 left panel). Therefore, there is a need in the art to be able to better utilize the anti-microbial power of ozone, chlorine, hypochlorite, and other sterilizing agents, particularly within the context of food processing of meat products having irregular surfaces to hide bacteria from exposure to oxidizing agents. The present invention was made to solve this need. SUMMARY OF THE INVENTION The present invention provides an sterilizing agent-laden fog useful for disinfecting irregular surfaces wherein the fog comprises water and a sterilizing agent selected from the group consisting of ozone, hypochlorite, chlorine and combinations thereof, wherein the fog is characterized by droplets having an average diameter of from about 0.0005 mm to about 0.05 mm, a weight of fog concentration in a treatment space is of from about 0.08 g/m 3 to about 0.8 g/m 3 . Preferably, the concentration of ozone in water of from about 0.5 ppm to about 30 ppm, the concentration of chlorine in water of from about 10 ppm to about 100 ppm, and the concentration of sodium chlorite of 0.001% to about 0.65% by weight based upon the total weight of said composition of sodium chlorite, whereby the chlorite ion concentration in the form of chlorous acid is not more than about 15% by weight of the total amount of chlorite ion concentration. Preferably, sterilizing agent is an aqueous solution consisting essentially of from about 1% to about 6% by weight of citric acid, and from about 0.001% to about 0.65% by weight based upon the total weight of said composition of sodium chlorite, such that the chlorite ion concentration in the form of chlorous acid is not more than about 15% by weight of the total amount of chlorite ion concentration. The present invention further provides a sterilizing fog generator device for generating a sterilant fog having droplets of an average diameter from about 0.0005 mm to about 0.05 mm, comprising: (a) an ozone gas injector for injecting gas into water and having a venturi nozzle; and (b) a vapor cell communicating with the ozone gas injector nozzle, wherein the vapor cell has a bottom and side walls and comprises an ultrasonic focused transducer located on the bottom of the vapor cell and wired to an electronic amplifier and an orifice direct toward a target for the ozone fog. Preferably, the sterilant fog is an ozone fog wherein ozone concentrations of from about 0.5% to about 20% by weight. Preferably, the ultrasonic transducer is operated at multiple frequencies of from about 0.75 MHz to about 2.0 MHz and at multiple pulse shapes, whereby the frequency and pulsed irregular wave forms control droplet size of the fog produced. Preferably, the orifice has a diameter of from about 0.1 cm to about 8 cm whereby the orifice size determines the density of the ozone fog generated. Preferably, the present invention further comprises a plurality of the vapor cells, connected in series or in parallel, and communicating to the target for the ozone fog through a single orifice. The present invention further provides a food disinfection immersion apparatus comprising (a) a means for forming an ozone gas; (b) a means for injecting the ozone gas into a water stream in an injection chamber, wherein the injection chamber further comprises a temperature controller, a pressure controller and an ultrasonic transducer to achieve the highest saturation level of gas in liquid; and (c) an immersion tank for disinfecting the food comprising an entry port for feeding the highly concentrated ozone water, a means for suspending the food product, and one or a plurality of ultrasonic scrubbers that agitate the food product surface microcavities to allow for deeper penetration of the highly concentrated ozone water. Preferably, the food disinfection immersion apparatus further comprises a means for injecting sodium hypochlorite and chlorine solutions into a water stream. The present invention further provides a method for disinfecting irregular surfaces, comprising contacting a product having an irregular surface for disinfecting with a sterilizing fog, wherein the ozone fog comprises water and a sterilizing agent and wherein the fog is characterized by droplets having an average diameter of from about 0.0005 mm to about 0.05 mm, a weight of fog concentration in a treatment space of from about 0.08 g/m 3 to about 0.8 g/m 3 , and an ozone concentration in water of from about 0.5 ppm to about 30 ppm. Preferably, the product having an irregular surface is a food product. Most preferably, the food product is red meat or poultry. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a schematic of an irregular surface of a food product (such as meat or poultry) having a micro-cavity that is often a site harboring bacterial growth (which forms the micro-cavity). The left panel shows a typical spray droplet in approximate relational scale having too much surface tension in order to penetrate and access the micro-cavity irrespective of the concentration or potency of anti-microbial oxidizing agent. The right panel shows the advantage of the inventive fog having a much smaller droplet size and an ability to access the reaches of a micro-cavity. FIG. 2 shows a schematic drawing of an inventive ozone fog generating apparatus having a contact chamber with the high concentration sterilant fog for disinfecting various meat products in an assembly line fashion. FIG. 3 shows the vapor cell component of the inventive apparatus in more detail. Specifically, acoustic transducers generate a high ozone concentrated fog in multiple vapor cells that is released through a variable orifice. FIG. 4 shows a standard curve of fall velocity of droplet is proportional to the square of the droplet diameter. DETAILED DESCRIPTION OF THE INVENTION The present invention provides a more useful ozone fog that is able to access irregular surfaces of food products, such as meats (muscle tissue), due to its very small droplet size coupled with a high ozone concentration in water. The irregular surfaces of meat products can harbor microbial contamination and provide a difficult surface for penetration or access of a liquid-based anti-microbial agent. For example, rain drops and low-pressure sprayers have or provide droplet sizes ranging from 0.15 mm to 0.5 mm. The smaller droplets of the inventive fog are better able to penetrate surface irregularities with “micro-cavity” regions where contaminating microbial growth is present (FIG. 1 right panel). An additional advantage of the smaller droplet size of the inventive fog is a significantly lower “fall velocity” or how fast the droplet will fall to a ground surface (see FIG. 4 ). The fall velocity of the droplets of the inventive fog is about 1000 times that of rain droplets or nearly 1000 cm/sec for rain compared with less than 1 cm/sec for the inventive fog (Schemenauer and Cereceda, Water Int ., 1994). The slower fall rate allows the inventive fog a longer contact time with the surface as it can “hover” over and adjacent to such a surface. In addition, the inventive ozone fog, having the smaller droplets, is more easily moved by fans and enclosures to fill the micro-cavities of an irregular surface and more uniformly surround surfaces for food treatment and a more even coverage. The inventive sterilizing fog generator preferably utilizes highly ozoneated water that can be created by injecting ozone gas into a water stream, such as with a venturi nozzle 17 . Additionally the ozone concentration can be increased by dissolving more ozone or another sterilant gas in the water through the use of ultrasonic transducers ( 14 ). High frequency high power sound waves cause the undissolved gas bubbles to rupture. Each time a bubble divides more gas is dissolved in the water. The ultrasonic transducer is connected to an electronic amplifier (e.g., acoustic driver 19 ) that is operated at multiple frequencies ranging from about 0.1 MHz to about 1. MHz. The highly ozoneated water is used to either feed an immersion tank for direct contact with food product surfaces, or to create the inventive fog in a vapor cell ( 13 ). In the case of an ozone fog, a vapor cell is filled with ozoneated water to a defined level, wherein the vapor cell further comprises an ultrasonic focused transducer ( 14 ) mounted at the bottom of the vapor cell (that is, completely immersed with ozoneated water). The transducer is connected to an electronic amplifier ( 19 ) that can be operated at multiple frequencies. Frequencies control droplet size and thus the control of the frequency settings control the resulting droplet size. However, a frequency setting between 0.75 MHz and 1.5 MHz will produce the desired droplet size with an average diameter of between 0.0005 mm and 0.05 mm. The vapor cell further comprises an orifice ( 22 ) to allow release of the inventive ozone fog. The density of the fog cloud released is a function of orifice size (diameter) wherein an orifice size of from about 0.1 cm to about 8 cm will produce an ozone fog having a density of between about 0.08 g/m 3 to about 0.8 g/m 3 . The orifice opens up to a contact chamber where the product to be disinfected is located. There may be one or a plurality of ozone fog generating devices to communicate with the contact chamber ( 12 ). In addition, a series of fans ( 24 ) can control the flow of the inventive ozone fog and direct it to a specific target surface or object. Moreover, the contact chamber can contain an exit port to allow for recycling of the ozoneated fog back into the vapor chamber for recharging of ozone concentrations. With regard to FIG. 1, A schematic diagram is provided that shows the importance of smaller droplet size able to penetrate irregular surfaces of food particles. The smaller droplet size is able to access bacterial-laden micro-cavities. With regard to FIG. 2, shows a preferred system for generating inventive ozone fog for contacting food in a food contact chamber ( 12 ). There is a water supply 10 pumped 11 to an ozone generator 16 to a recirculation loop 17 having an ozone injector such as a Venturi nozzle. The ozone is supplied to a plurality of acoustic transducers 14 via a ozone supply line 18 and returning via a return line 15 . The acoustic transducers communicate with multiple vapor cells 13 and are controlled by acoustic drivers 19 that have vapor density control 20 and leveling and other controls 21 . Through an orifice 22 in each vapor cell 12 , the inventive ozone fog is released into contact chamber(s) 12 to sterilize food surfaces. With regard to FIG. 3, two acoustic transducers are shown connected to a supply of fresh ozone-enriched water. The fog is formed in adjoining vapor cells. The transducers are commercial ultrasonic focused transducers, such as from Panasonic or others. Although not shown, there is a water recirculation loop to provide only the freshest ozonated water to the transducers. There is a liquid coupling cell to couple the sound to the surface as there is a distance (focal length) needed where the ultrasonic energy is focused onto the surface of the ozoneated water stream. The disruption on the surface of the water stream is from the focused ultrasonic energy to form small droplet ozone fog in the vapor cell. An air supply fan conveys the fog out of the vapor cell, through a variable orifice into a chamber. Preferably, an ozonated air supply is blown (via a fan) to clear the fog our of the vapor cells and through the variable orifice. Alternatively, a food product may be immersed in an immersion tank (not depicted) containing highly ozoneated water. The immersion tank further comprises an entry port for feeding the highly concentrated ozone water, a means for suspending the food product, and one or a plurality of ultrasonic scrubbers that agitate the food product surface microcavities to allow for deeper penetration of the highly concentrated ozone water. It is the presence of the ultrasonic scrubbers that allow for access of the highly ozoneated water into contact with micro-organisms within the microcavities (due to disruption of the food surface) and that creates a better disinfection of food products using the inventive device. Various food (meat) products were tested for disinfection using either a misting of ozonated water using prior art techniques, an immersion in either highly ozoneated water or standard immersion techniques, or contact with the inventive ozone fog. In each test the sample in contact with the ozone fog measured the lowest bacterial counts. The example below provides results from one of these tests. EXAMPLE 1 This example provides the results of an experiment comparing various means for disinfecting food products using a standard ozone mist technique with large droplet sizes and lower concentrations of ozone and standard dipping techniques to the inventive fog. In this case the sample under test was a rump roast purchased from Safeway (a supermarket chain) and packaged 28 days earlier in Wichita, Kans. Table 1 list results as measured by the Benton-Franklin health district. All analysis were performed using methods outlined in the districts Standard Methods for the Examination of Water and Wastewater , 18 edition. TABLE 1 O 3 /water Bacteria ppm application count comment 1.36 Mist 4.92 × 10 5 Sample with least exposure to air 4.25 Fog  1.3 × 10 5 Least amount of applied water 0.25 Dip 5.15 × 10 5 Lowest conc. but full immersion 5.1 Mist 1.28 × 10 6 Sample on counter the longest before ozoneating (touched with hands none Control 1.13 × 10 6 Control sample no disinfection The ozone concentration in water was measured using an Ozotech calibrated 03 probe. It should be noted that the fog application yielded a bacterial count nearly 5 times lower than any other technique and nearly 10 time lower than the control sample. Table 1 also illustrates the inconsistency of a standard spray application independent of concentration. Finally, in accordance with the methods of analysis cited above the samples are measured at 24 hours from disinfection and again at 48 hours from disinfection. This “incubation period allows” stressed bacteria to fully recover. Standard techniques can at best stress bacteria located in microcavities, which is indicated by a low plate count followed by a much higher plate count after the set recovery time. The ozone fog application kills bacteria located in the micro-cavity that is indicated by a low plate count initially as well as after the recovery time. EXAMPLE 2 This example provides the test results of another experiment of product samples of beef and chicken and determining bacterial counts (Benton County and Franklin County (Wash.) Health Department) taken 24 hours after ozone exposure. The test compared the inventive ozone fog to control (no ozone exposure), a mist spray of ozone with large droplet size and a dip or immersion of ozone. The samples were not covered during the 24 hour waiting period and could have been recontaminated. The actual measurements was taken an additional 48 hours from the time of the swab to allow for proper incubation and this also could have allowed for stressed bacteria to recover. Table 2 provides the results showing a significantly greater effectiveness with the inventive fog despite less use of ozone and exposure. TABLE 2 Application Diluted ozone conc. % Bacteria 24 hrs later None na 100%  fog 0.04 12% Spray/mist 0.5 78% dip 0.25 46% These data further support the surprising results achieved with the inventive fog.

There is disclosed a sterilizing fog, characterized by droplet size range, vapor density range, sterilant concentration range and sterilant concentration within the droplets. Specifically, there is disclosed a fog achieved by an apparatus combining pressure, temperature and acoustics to form a super-charged ozoneated water and an apparatus that creates small micro droplets which form a highly concentrated sterilizing fog. Specific sterilants used are ozone, chlorine and chlorous acid generating compositions such as sodium hypochlorite, or combinations thereof.

This application is the US national phase of international application PCT/GB03/00446 filed 31 Jan. 2003 which designated the U.S. and claims benefit of EP 02250674.5, dated 31 Jan. 2002, the entire content of which is hereby incorporated by reference. FIELD OF TECHNOLOGY The present invention relates to a method of selecting network services from a plurality of network services available for a communication. BACKGROUND Conventional telephony networks offer a service which reserves 64 kbits −1 of the network's capacity for the duration of a user's call. This service is suitable for voice telephony, where a signal representing the voice of the user must be continuously sent across the network to the other party to the conversation. In the trunk links of the telephony network, a number of telephone calls are carried on the link, each having its own timeslot in a sequence of timeslots. This is known in the art as time division multiplexing. In contrast to telephones, computers send data in bursts (e.g. a Web server might send a page at 1 Mbits −1 for a few milliseconds once every minute on average). Reserving 1 Mbits −1 permanently for communication from a computer would be inefficient. For this reason, dedicated computer networks offer a different type of service. They do not reserve capacity for a user, but instead offer a service where the resources of the network (or at least a proportion of those resources) are shared indiscriminately between network users. This is known in the art as statistical multiplexing. The last two decades have seen the introduction of so-called ‘integrated’ networks which are designed to carry both computer communications and telephony. The capacity of those networks therefore needs to be allocated between users who require a constant bit-rate for the duration of a communication (e.g. telephone users) and those who can tolerate some variation in the bit-rate supplied to them by the network (e.g. those transferring web-pages, software or e-mails). In order to accommodate the different requirements of different types of communication, one type of integrated network, an Asynchronous Transfer Mode (ATM) network, allows a user to choose between a constant bit-rate service type (in which an amount of bandwidth they request is allocated to them for the duration of a session), a variable bit-rate service type (in which a proportion of the available capacity is shared between a number of users controlled to substantially prevent congestion), and an unspecified bit-rate service type (in which the remaining capacity is simply shared by all users). In the first two types of service, a user can additionally specify the amount of bandwidth he or she wishes to have available. Note that ‘service’ is to be distinguished from ‘service type’—a specification of a required service will include both a service type and an indication of the amount of network resources required by the user. Similarly, another type of integrated network, an Internet Protocol (IP) network, can also offer a constant bit-rate service type (using the Resource Reservation Protocol (RSVP)), and a best efforts service type which approximates to the unspecified bit-rate service offered by ATM networks. Another service type gives packets sent by one class of users priority over packets sent by another class of user. Using RSVP, a user can additionally specify the amount of bandwidth he or she wishes to have available. SUMMARY In summary, integrated networks offer their users the ability to specify the service which they wish to receive from the network (which, being an integrated network, can offer a plurality of different services). This specification can be made once at the start of a communication (the normal procedure in networks offering a connection-oriented service, such as ATM networks) and/or repeatedly during a communication. Where a person has to make such a service specification many times because he or she is involved in a number of different communications and/or has to make a plurality of service specifications during a communication, it is beneficial if that specification is made on that person's behalf by a computer programmed to act as that person's agent. An example of a computer programmed in this way is found in PCT application number WO 01/52475. That application describes how a web-server programmed by a content provider requires indicates, in a ‘bid’, how much the content provider is prepared to pay for three different amounts of constant-bit rate resource for the following thirty second reservation period. That bid is then made repeatedly at thirty second intervals throughout the communication. The resources of the network are then allocated between communications by a bandwidth broker computer which receives current bids from all those requiring reserved capacity on the network. This arrangement is deficient in that the web-server is unable to give any indication of the type of service the content provider requires from the network. This leads to an inefficient allocation of network resources and means that the programmed computer can only be used with networks which offer a constant bit-rate service type for a predetermined reservation period. European Patent application 0 848 560 and U.S. Pat. No. 6,104,720 both disclose an apparatus which selects between a plurality of service types in accordance with Quality of Service parameters input by a user. The QoS parameters considered include throughput, packet loss, latency and jitter. According to a first aspect of the present invention, there is provided a method of selecting a network service from a plurality of network services available for a communication, said method comprising: storing utility data representing the utility of one or more corresponding levels of communication resource provided for said communication during said communication; storing an indication of the stability in the amount of said communications resource provided for a communication by one or more services offered by said network; calculating, from said service stability data, one or more measures of the likelihood of a predetermined variation occurring in the amount of resource provided for said communication by a service at a future time during said communication; selecting, in dependence upon said likelihood measures and said utility data, a network service for said communication. By calculating the expected utility offered by candidate network services from service stability data and utility accumulation rate data for different levels of communication resource, a more efficient method of allocating a network's resources between calls than has hitherto been achieved is provided. Utility is here meant in an economic sense—i.e. the utility of a service represents the price a purchaser is prepared to pay for that service. Where a service is charged for per unit time, the utility accumulation rate may be used. Utility represents a preferred measure of the importance of a service to a person requiring that network service. The demand for money or money's worth from the person requiring the communication results in that person genuinely indicating the importance of the service to him or her. Where other indications of importance are used, a user may just indicate that all communications he or she requires are of high importance. The present invention is useful both in situations where said selection step involves a determination of what service to request for said communication and where said selection step involves a determination of what service to provide for said communication. Preferably, said service stability data comprises data defining a probability density function defining the likelihood of a variable lying within a range of values at a time after said selection, wherein said variable determines the amount of resource provided for a communication by a service. The variable might represent the amount of bandwidth available for said communication in a variable-bandwidth service or the price of a dynamically-priced service. A dynamically-priced service is one where constant bit-rate reservations can be made, but for a predetermined reservation period that is shorter than the duration of many communications. Furthermore, the cost of reserving that bandwidth may change from one reservation period to the next. Preferably, the maximum of said probability density function is set to the value of said variable at the time of said selection. This embodies an assumption that it is more likely that the amount of resource or the price of a fixed amount of resource will stay the same than it is that any other specific variation will occur. Alternatively, the probability density functions could reflect the time-of-day at which the communication is made. In other embodiments which involve prediction, said utility data comprises utility accumulation data which might itself comprise one or more utility accumulation rates. Preferably, in embodiments involving prediction and using utility accumulation rates as indicia of the importance of a given service, said utility accumulation data comprises one or more utility indications each comprising a transmission rate and an associated utility accumulation rate for that rate; said likelihood calculation involves calculating measures of the likelihood of said service type providing said communication with said transmission rate at said future time; and said selection involves calculating an expectation of the surplus which would be accumulated by said communication over a predetermined period were said service type to be selected, the calculation of said expectation involving calculating the sum of the products of said likelihood, the associated utility accumulation rate and the duration of said predetermined period. The predetermined period may either be: i) the duration of the communication if the selection is made at the start of the communication; or, where the selection is made during the communication: ii) a known reservation period; or iii) the duration of the remainder of the communication. Where data associating the resources provided to the user with a utility accumulation rate is available, it is possible to calculate an expectation of the surplus that will be accumulated over said predetermined period for variable-bandwidth services (i.e. services which involve statistical multiplexing of a plurality of communications), constant bit-rate services and dynamically-priced services. Hence, the utility (expected to be accumulated over said predetermined period) of a communication supported by each of these types of services can be calculated. This enables a comparison of any of those service types with one another and the selection of the service type which best suits the requirements of the person (or his agent) requesting the communication. In preferred embodiments, the expected surplus additionally takes into account a penalty the user associates with moving from one transmission rate to another. Penalties might only be associated with drops in bandwidth or might be associated with increases in the amount of bandwidth allocated to a communication as well. The penalties may take the form of a one-off cost to be subtracted from the expected surplus. According to a second aspect of the present invention there is provided a network service selection apparatus comprising: a storage medium having recorded therein processor readable code processable to select a network service for a communication, said code comprising: stability desirability data reading code processable to read one or more stored utility accumulation rates representing the utility of one or more corresponding levels of communication resource provided for said communication during said communication; likelihood calculation code processable to calculate, from stored service stability data representing an indication of the stability in the amount of said communications resource provided for a communication by one or more services offered by said network, one or more measures of the likelihood of a predetermined variation occurring in the amount of resource provided for said communication by a service at a future time during said communication; and network service selection code processable to select, in dependence upon said likelihood measures and said one or more utility accumulation rates, a network service for said communication. According to a third aspect of the present invention, there is provided a program storage device readable by a processing apparatus, said device embodying a program of instructions executable by the processor to perform the steps of the method according to the first aspect of the present invention. According to a fourth aspect of the present invention, there is provided a method of selecting, during a communication, a network service from a plurality of network services available for said communication, said method comprising: storing stability desirability data representing the importance of stability in the amount of communication resource provided for said communication during said communication; identifying the service currently being provided for said communication; selecting, in dependence upon said stability desirability data and said identified service, a network service for some or all of the remainder of said communication. This has the advantage of making the likelihood of in-session switching depend upon the importance that the user attaches to stability in the amount of communications resource he receives from the network. In this fourth aspect, the stability is, at least in part, determined by the selection. For example, if a purchaser is paying for 300 kbits −1 of reserved bandwidth prior to a selection between 100 kbits −1 , 300 kbits −1 and 500 kbits −1 services for the next part of the communication, the data representing the stability requirement might determine whether the purchaser continues to receive 300 kbits −1 or not. According to a fifth aspect of the present invention, there is provided a method of selecting network services from a plurality of network services available for a communication, said method comprising: storing stability desirability data representing the importance of stability in the amount of communication resource provided for said communication during said communication; and selecting, in dependence upon said stability desirability data, network service for said communication. The present inventors have realised that a single characteristic, the desirability of stability, distinguishes the desirability of a large number of network services. By quantifying a communication's requirement for stability in the amount of resource provided for it, it is possible for a programmed computer to select the most appropriate service for that communication from a network that offers many different services. This enables a more efficient allocation of the resources of that network between communications having different requirements. Furthermore, quantifying the desirability of stability enables the same computer program and stability desirability data to be used for communications over a variety of networks. This reduces the technical effort that goes into producing bespoke programs for networks offering different services. It might also reduce the amount memory required to store such programs (since one copy of the program can control network service selection for a variety of networks). Yet further, a person wishing to send a similar communication over a plurality of networks need only generate one specification of the service they require for such similar communications. In one set of embodiments, said method further comprises the step of storing an indication of the stability in the amount of said communications resource provided for a communication by one or more services offered by said network, wherein said selection step involves determining from said service stability indication and said stability desirability data a network service for said communication. This enables the stability that will be obtained for a communication to be predicted—enabling a selection of a suitable network service for said communication prior to the start of said communication. Preferably, said method further comprises the step of calculating, from said service stability data, a measure of the likelihood of a predetermined variation occurring in the amount of resource provided for said communication by a service at a future time during said communication. This has the advantage of simplifying the processing involved in selecting a suitable network service and thereby reducing the load on the processing resources of a computer programmed to perform the above method. BRIEF DESCRIPTION OF DRAWINGS By way of example only, specific embodiments of the present invention will now be described with reference to the accompanying Figures in which: FIG. 1 shows an internetwork in which a first embodiment of the present invention is implemented; FIG. 2 shows a regional cable network portion of the internetwork of FIG. 1 in more detail; FIG. 3 shows a regional Digital Subscriber Loop network portion of the internetwork of FIG. 1 in more detail; FIG. 4 shows quality of delivery policy data generated by a content provider for a content file; FIG. 5 shows the flow of messages between devices in a session initiation phase of the first embodiment; FIG. 6 shows the flow of messages between different devices of FIG. 1 in a first part of a content file request phase of the first embodiment; FIG. 7 shows a user/content-specific quality of delivery specification generated following the first part of a content file request phase of the first embodiment; FIG. 8 shows the flow of messages between devices in a second part of a content file request phase of the first embodiment; FIG. 9 illustrates a probability density function of the bandwidth available within a one of a plurality of variable-bandwidth service offering from the regional cable network at a time T after bandwidth b i was available for each user of that service; FIG. 10 illustrates a probability density function of the price requested for a dynamically-priced service offering from the DSL network operator at a time T after price $ i was requested; FIG. 11A shows network service data stored at the bandwidth broker computer of the cable network of FIG. 2 ; FIG. 11B shows network service data stored at the bandwidth broker computer of the DSL network of FIG. 3 ; FIG. 12 shows a process for building a blacklist of service offerings unsuitable for the current content file delivery; FIGS. 13A and 13B show processes for calculating, at the start of the delivery, the probability of a premature delivery cessation for variable-bandwidth and dynamically-priced services respectively; FIG. 14 shows an initial service selection process carried out by the bandwidth roker computer at the start of the delivery of a content file; FIG. 15 shows a process for calculating the session surplus for each indicated service when a constant bit-rate service offering is used to deliver a content file; FIG. 16 shows a process for evaluating the session surplus for each indicated service when a dynamically-priced service offering is used to deliver a content file; FIG. 17 shows a process for evaluating the session surplus for each indicated service when a variable-bandwidth service offering is used to deliver a content file; FIG. 18 shows the calculation of expected penalised second-half session surplus used when considering using a variable-bandwidth service offering or a dynamically-priced service offering for the first half of a content file delivery; FIG. 19A shows the calculation of expected penalised second-half session surplus where a dynamically-priced service offering is used for the second half of a content file delivery; FIG. 19B shows the calculation of a sequence of indicated services followed by a purchaser using a dynamically-priced service offering in response to the price of bandwidth in that service rising; FIG. 19C shows the calculation of the probability of a purchaser choosing an indicated service for the second-half of a content file delivery assuming that a dynamically-priced service offering is used in the second-half; FIG. 20A shows the calculation of expected penalised second-half session surplus where a variable-bandwidth service type is used for the second half of a content file delivery; FIG. 20B shows the calculation of a sequence of indicated services followed by a purchaser using a variable-bandwidth service offering in response to the amount of bandwidth available for a content file delivery rising; FIG. 20C shows the calculation of the probability of a purchaser choosing an indicated service for the second-half of a content file delivery assuming that a variable-bandwidth service offering is used in the second-half; FIG. 21 shows the selection of a service type at a subsequent service selection point during the delivery; FIG. 22 shows a process used to evaluate a penalised session surplus for each indicated service when a constant bit-rate service offering is used immediately after the subsequent service selection point; and FIG. 23 shows a process used to evaluate a penalised session surplus for each indicated service when a variable-bandwidth service offering is used immediately after the subsequent service selection point. DETAILED DESCRIPTION FIG. 1 shows an internetwork comprising a content provider's local area network 100 , a regional cable network 140 , a regional Digital Subscriber Loop network 180 , and a portion of the global Internet 120 which interconnects all three. The content provider's network 100 comprises a content provider's Web server 102 and origin video server 104 , an Internet router 106 and a LAN 108 interconnecting them. The regional cable network is illustrated in more detail in FIG. 2 . The regional cable network 140 comprises a hybrid fibre/co-axial (HFC) cable network 142 , a regional head end 170 which connects the regional cable network to the global Internet 120 , a regional fibre network 150 , a caching network 144 , a Layer 4 switch 148 and a Cable Modem Termination System (CMTS) 146 which interconnects the Layer 4 switch 148 and the HFC cable network 142 . The Layer 4 switch interconnects the regional fibre network 150 , the caching network 144 , and the CMTS 146 . A suitable CMTS is the Cisco uBR 7246 which operates in accordance with a pre-standard version of the DOCSIS (Data Over Cable Service Interface Specification) standard version 1.1. The Cisco uBR 7246 also schedules IP packets which transit it in accordance with the value of the so-called Differentiated Services (DS) field in the IP packet header (see the Internet Engineering Task Force's Request For Comments (RFCs) 2474 and 2475 for details of the DS field). The HFC network 142 comprises a large number of sets of user equipment ( 152 - 156 ), a plurality of co-axial cable networks 157 serving around 700 homes each, a fibre ring 158 , and a number of fibre nodes 160 , each of which connects the fibre ring 158 to one of the co-axial cable rings 157 . Each set of user equipment ( 152 - 156 ) comprises a Toshiba PCX 1100 cable modem 154 (a pre-standard DOCSIS 1.1-compliant cable modem), a Personal Computer (PC) 152 , a cable 153 leading from the modem 154 to the PC 152 , a cable 155 extending from each set of user equipment to a tap 156 on the co-axial cable ring 157 . The caching local area network 144 comprises an agent computer A 1 , a content file caching server C 1 , a shaper/marker 164 , a bandwidth broker computer B 1 , and a Local Area Network 162 which interconnects them. The Local Area Network 162 operates in accordance with the Institute of Electrical and Electronics Engineers (IEEE) 802.3 standard at a rate of 100 Mbits −1 . The 155 Mbits −1 Lucent Access Point 1000 (AP1000) supplied by Lucent Technologies Inc., 600 Mountain Avenue, Murray Hill, N.J., USA would provide a suitable shaper/marker ability. In accordance with a first embodiment of the present invention, the CMTS 146 is configured as follows. Three diff-serv codepoints (say 111000, 110000, and 000000) are chosen to represent top-priority traffic, mid-priority traffic and best effort traffic respectively. The CMTS/IP Router 146 is able to offer each type of traffic simple priority over traffic of the next lowest level of priority. The IP router component of the head end 170 is configured to reset (to 000000) the DS fields of packets arriving over the Internet link 9 which have their DS field set to a value which is equated to any other priority level than best effort. The agent computer A 1 is provided with a HyperText Transfer Protocol client program which is configured to use the caching server computer C 1 as a proxy (in other words, HTTP requests from the agent computer will be received by the caching server computer C 1 and forwarded if the caching server computer itself cannot satisfy the request. HTTP responses to those requests will be received by the caching server computer and forwarded to the agent computer A 1 ). The regional Digital Subscriber Loop Network ( FIG. 3 ) comprises a user's personal computer 10 , an ATM network 2 , a cable 12 connecting the user's PC 10 to the ATM network 2 , an Internet Service Provider's (ISP's) local area network 4 , a Broadband Access Server (BAS) 6 , an ATM network link 5 which connects the BAS 6 to the ATM network 2 and an ISP network link 7 which connects the BAS 6 to the ISP's local area network 4 . In the present embodiment the BAS is provided by a modified Nortel Networks Shasta 5000 Broadband Service Node. The ISP's local area network 4 is connected to the Internet 120 via an Internet link 9 . A charging server 28 is connected to the BAS 6 via a router 32 and a Local Area Network 31 . The ATM network 2 comprises a large number of sets of user equipment ( 11 , 13 14 ), pairs of copper wires 16 extending from each set of user equipment ( 11 , 13 , 14 ) to a local exchange 20 , exchange-housed equipment ( 17 , 18 ) housed in the local telephone exchange building 20 and a wide-area switched network 22 which connects a plurality of such DSLAMs 18 (there is normally one or more DSLAMs per exchange building, only one exchange building is shown in the drawing) to the BAS 6 . As will be understood by those skilled in the art, the exchange-housed equipment includes a Digital Subscriber Line Access Multiplexer (DSLAM) 18 shared between many users and, for each pair of copper wires 16 , a splitter unit 17 which terminates the pairs of copper wires 16 . The splitter unit 17 is effective to send signals within the frequency range used for normal telephony to the Public Switched Telephone Network (not shown) and to send signals in higher frequency bands to the DSLAM 18 . Each set of user equipment ( 11 , 13 , 14 ) comprises a splitter unit 14 in a customer's premises which incorporates an Asymmetric Digital Subscriber Line (ADSL) modem 13 . The splitter unit 14 is effective to send signals within the frequency range used for normal telephony to the user's telephone 11 and to send signals in higher frequency bands to the ADSL modem 13 . The ADSL modem 13 represents the network termination point of the ATM network 2 . Cable 12 leads from the modem 13 to the PC 10 . The ISP's local area network 4 comprises an IP router 24 , a cache computer C 2 , an agent computer A 2 , a bandwidth broker computer B 2 , and a Local Area Network 30 which interconnects them. The previously mentioned Internet link 9 is connected to the IP router 24 . The Local Area Network 30 operates in accordance with the Institute of Electrical and Electronics Engineers (IEEE) 802.3 standard at a rate of 100 Mbits −1 . That capacity, the capacity of the ISP link 7 and the ATM network 2 is sufficient to ensure that the rate of transmission of a stream of packets between the caching computer C 2 and the personal computer 10 is determined by the BAS 6 . It is to be understood that each of the elements of the internetwork ( FIG. 1 ) operates in accordance with version 6 of the Internet Protocol (IP). Furthermore, at least the caching computer C 2 offers the differentiated services extensions to the UNIX sockets interface, or any other programming interface that enables the setting of the Differentiated Services (DS) field in the IP packet header. In accordance with a first embodiment of the present invention, the ATM network ( FIG. 3 ) is configured by the ATM network operator as follows. Firstly, an ATM permanent virtual circuit (PVC) is configured between the BAS 6 and each of the modems it serves. The PVC is a constant bit rate (CBR) connection whose peak cell-rate is set to 2 Mbits −1 . The ATM network operator also configures each PC 10 with an IP address. Thereafter a table associating the IP address of each PC with a label that identifies the PVC which leads to that PC 10 is created in the BAS 6 by manual or automatic methods that are well-known to those skilled in the art. In a conventional manner, the BAS 6 receives a frame constructed in accordance with the link-layer protocol used over the ISP link 7 . The link-layer header and/or trailer is then removed from the frame to leave a packet constructed in accordance with the Internet Protocol. The BAS 6 forwards the packet in a manner which depends upon the DS field of the IP packet header. Thus, a packet may be provided with a constant bit-rate service (where a given amount of bandwidth is reserved for the delivery of the content file), or a best efforts service. On sending packets over the interface, a (Point-to-Point Protocol) PPP link-layer interface header and trailer are added a frame constructed in accordance with the PPP link-layer protocol. The frame thus constructed is then passed through the ATM Adaptation Layer 5 (AAL5) segmentation process in which it is split into ATM cells and sent onto the ATM PVC connection. Similar processes are carried out for each packet being received from the link-layer interface to the ISP link 7 . The router 24 is configured to reset (to 000000) the DS fields of all packets arriving over the Internet link 9 . Returning now to FIG. 1 , the content provider's Web server computer 102 is provided with a web server program, and a program for preparing delivery policies for content files. The web server program controls the Web server computer 102 to send web-pages requested by a user to that user and to gather information about users in order to enable the quality of the delivery provided to a user to depend upon the user's identity. In the present embodiment, this is achieved by asking users to fill in a HyperText Mark Up Language (HTML) form in order to register with the web-site. The form asks the user for a user name and password and various other data such as the user's age, gender, nationality and occupation category. The information provided is used to assign a user to a user class. A table giving the class of each user is stored at the Web server 102 . Those skilled in the art would be able to write a suitable Web server program. Using the program for preparing delivery policies for content files, the content provider also creates a delivery policy ( FIG. 4 ) for each content file. The program asks the content provider to indicate: i) the name of the content file; ii) the format of the content file; iii) the duration of the content file in seconds; iv) for each class of delivery, the maximum risk of premature delivery cessation which the purchaser considers acceptable; v) for each class of delivery, for each of one or more indicated services (in the present case, the choice of services to indicate (i.e. to list) is made by the purchaser and each indicated service is specified by a transmission rate), a utility accumulation rate (in pence/sec) representing how valuable that indicated service is to the content provider; vii) for each of the one or more indicated services a one-off utility penalty (in pence) occasioned by the transmission rate offered by the network dropping such that the rate drops to the rate associated with the immediately lower indicated service, including the penalty associated with dropping from the lowest rate to no transmission at all. In fact an indicated service of zero bandwidth is assumed which offers the user no utility. In the present example, for each class of delivery, the user inputs parameters for three indicated services, namely—400 kbits −1 , 250 kbits −1 and 100 kbits −1 . The delivery policy generation program then produces a data structure containing the data seen in FIG. 4 —the penalties associated with a drop through more than one indicated service are calculated by the delivery policy generation program from the penalties supplied by the content provider. Those skilled in the art will have no difficulty in providing a program to collect the above data and generate the delivery policy data structure shown in FIG. 4 . Once created the content provider stores the delivery policy at a URL having a predetermined relationship to the content file's name—for example the content provider owning the domain name cp.com might store its delivery policy file for the content file www.cp.com/latest/gladiator.rm at: http://www.cp.com/qospolicy/latest/gladiator.rm The content provider then includes the URLs pointing to its delivery policy files in the list of files which it wishes to be copied to caching servers such as caching server C 1 in the regional cable network ( FIG. 2 ) and caching server C 2 in the DSL regional network ( FIG. 3 ). As will be understood by those skilled in the art, content distributors offer a service in which they copy specified files from an origin server to caches around the world. In the present embodiment, use of such a service results in the content files stored on origin video server computer 104 being copied to the caching servers C 1 and C 2 , together with the content provider's delivery policy files associated with those content files. FIGS. 5 , 6 , 7 and 8 illustrate the operations carried out by the customer's PC 152 , the content provider's origin Web server O, and the cable network's ( FIG. 3 ) agent computer A 1 , caching server C 1 and bandwidth broker B 1 in carrying out the method of the present embodiment. In fact, the steps carried out by the personal computer 152 are carried out under the control of a conventional browser program such as Netscape's Navigator version 4. FIG. 5 shows the steps involved when a previously registered user at PC 152 browses the home page of the content provider. The home page includes a form as provided for by HyperText Mark Up Languages HTML 2.0 and above. As will be understood by those skilled in the art, the form as presented to the user has text fields into which the user must enter his user name, and a submit button. The HTML file representing the web-page will also contain a URL which points to a Common Gateway Interface script (i.e. an executable program) and a further indication parameter not displayed to the user that indicates the web-page has been generated for a registered client of the caching server operator. When the user clicks on the submit button, the browser program running on the PC 152 sets up a Transmission Control Protocol (TCP) connection to the Layer 4 switch 148 and sends a HyperText Transfer Protocol (HTTP) GET request across that TCP connection (step 1 ). The layer 4 switch 148 is configured to redirect all requests destined for the default ports used for each content file type to the cache (e.g. port 80 for http and port 554 for rtsp). This avoids the browser program stored on the PC 152 having to be configured to point to the caching computer C 1 . The GET request is accompanied by the user name and the indication parameter. The Layer 4 switch 148 recognises the TCP port value in the GET request and hence forwards the request to the caching server C 1 . A plug-in program on the caching server C 1 recognises that the request must be forwarded to the origin server O and, since the indication parameter is present (the indication being the indication cache_service_client=true which forms part of the Universal Resource Locator (URL) in the original GET request), appends an indication of the agent computer A 1 , appends the user's IP address and then sets up a further TCP connection to the origin Web server O and passes the modified GET message across that connection (step 2 ). The origin Web server O receives the GET message and the appended user name, client indication, and agent identifier. In response, it runs the associated CGI script which causes it to: a) fetch from the user database the user class, and then send that user class and an indication of the user's current Internet address to the agent computer A 1 identified by the agent identifier in the received message (step 3 ); and b) send an HTML file representing a registered user menu page to the PC 152 (step 4 ). The HTML file includes one or more hyperlinks to content files previously copied to the caching server C 1 by a content distributor as described above. On receiving the user class message, the agent computer A 1 stores the user class along with the user's current IP address. Once it is received, the user's PC 152 presents the HTML file as a registered user menu page on the screen of the PC 152 . The registered user menu page includes one or more hyperlinks which are associated with content files stored on the caching server C 1 . Turning now to FIG. 6 , on the user selecting one of those hyperlinks, an RTSP SETUP request is sent to the Layer 4 switch 148 . As before, the HTML file includes a HTML form which causes a further registered client indication to be included in the SETUP request. The Layer 4 switch 148 recognises the TCP port in the request and hence forwards the request to the caching server C 1 (step 5 ). On receiving the SETUP request, the plug-in program at the caching server C 1 responds to the presence of the further registered client indication by controlling the caching server C 1 to send a content file transfer parameters message to the agent computer A 1 which includes the URL of the requested content file, values of the user's TCP port and IP address, and the origin server's TCP port and IP address (step 6 ). On receiving the content file transfer parameters message the agent computer A 1 fetches the delivery policy ( FIG. 4 ) associated with the content file identified in the content file transfer parameters message (step 7 ). The agent computer A 1 then looks up the stored user class (which it received in step 3 ) associated with the IP address received in the content file transfer parameters message (received in step 6 ). The agent computer A 1 then selects the set of class-specific quality of delivery parameters which corresponds to the stored user class from the delivery policy file received in step 7 . The selected set is then incorporated in a quality of delivery specification for this specific User/Content-File combination ( FIG. 7 ) which is forwarded (FIG. 8 —step 8 ) to the bandwidth broking computer B 1 . For variable-bandwidth service offerings, the amount of bandwidth available for a delivery of a content file will either stay the same, decrease or increase. However, the amount of bandwidth offered cannot decrease below zero. Equation 1 below is a probability density function which, for a variable-bandwidth service offering which offers bandwidth b i for a delivery at time t=0 can be integrated over a bandwidth range between a lower bandwidth and an upper bandwidth to give the probability of the bandwidth being in that bandwidth available for a delivery range after a given time period T. p n ⁡ ( b ) = c ⁢ ⁢ b 2 kT ⁢ ⅇ - ( b - b i ) 2 kT Equation ⁢ ⁢ 1 C is chosen so that: ∫ 0 ∞ ⁢ p n , T ⁡ ( b ) ⁢ ⅆ b = 1 The value k in the above expression is a volatility index which expresses the volatility in the amount of bandwidth the service offering supplies to a user—higher values of k represent greater volatility. FIG. 9 illustrates the form of the above probability density function which represents the likelihood of a bandwidth b being offered at a time T after an amount of bandwidth b i was offered. As will be understood by those skilled in the art, the area under the curve up until the line labelled bm represents the probability that less bandwidth than b m is available at time T. The ‘width’ of the peak of the distribution grows as the square root of time. An analogous probability density function can be used to model the variation of price in a dynamically-priced service offering. FIG. 10 shows such a probability density function, including examples of so-called marginal prices at which the content provider (or other purchaser) would choose to move between services indicated in the quality of delivery policy ( FIG. 4 ). $ 3|2 for example, represents the price below which the purchaser would choose the highest of three indicated services in preference to the other indicated services and just above which the purchaser would choose the second highest indicated service. It is to be noted that FIG. 10 represents a simple situation. In FIG. 10 , the lowest marginal price is that at which the indicated service obtained by the purchaser drops from the highest indicated service to the next highest indicated service. That behaviour is seen when the unit value of bandwidth decreases with increasing bandwidth—however, in some indications a purchaser may place an increasing value on a unit of bandwidth as bandwidth increases. The bandwidth broking computer B 1 stores network data ( FIG. 11A ) specific to the regional cable network. The network data indicates the different service offerings (first row) which are available in the cable network, and the bandwidth currently available to a user of each service offerings (fifth row), together with the price of bandwidth (fourth row) in each service. Also indicated is the type of each of the service offerings (third row). A service offering number is associated with each of the services (second row). Finally, the value of the volatility index to be used in obtaining the probability density function which describes the amount of bandwidth at a time T after bandwidth b i was available is given for each of the service offerings (sixth row). In the present example, the data ( FIG. 11A ) indicate that the cable network offers a high-priority (Priority 1 ) service offering, a mid-priority (Priority 2 ) service type and a best-effort service type. All three services are variable-bandwidth services—the volatility of the services increasing in the above order. In contrast, the network data ( FIG. 11B ) stored at the bandwidth broker computer B 2 of the DSL network ( FIG. 3 ) indicates that the DSL network offers two service offerings, the first being of the constant bit-rate type and the second being of the dynamically-priced type. As with the cable network, the price of bandwidth and the amount of bandwidth available to a user are given. Also given is the volatility of the price of the dynamically-priced service offering. FIGS. 12 to 23 are flow charts illustrating the operation of a computer under the control of a ‘generic’ network service purchasing agent program—the program is ‘generic’ in the sense that it can select between constant bit-rate, variable bandwidth and dynamically-priced services. In the present embodiment, the program is executed by a network's bandwidth broker computer (B 1 or B 2 ) when that computer receives a quality of delivery specification from the local agent computer (A 1 or A 2 ). The program is stored in a storage medium, which is a particular form of a program storage device. On receiving the quality of delivery specification ( FIG. 7 ) for this content file/user combination ( FIG. 8 , step 8 ) the bandwidth broker computer generates a blacklist of those service offerings available from the network which do not meet the acceptable risk requirement as out in the quality of delivery specification. The generation of the blacklist ( FIG. 12 ) begins with the setting out of the list of known network service types (step 220 ). The process then enters a loop of instructions (step 224 to step 246 ), each iteration of that loop involving the carrying out of a service offering evaluation process. The service offering valuation process begins with a check to find whether the nth service offering by the network is of a recognised type (step 226 ). If it is not included in the service type list generated in step 220 then the bandwidth broker computer (B 1 or B 2 ) reports the presence of an unknown service type (step 228 ). If the service type is recognised then a test (step 230 ) is carried out to find whether the service is of a constant bit rate type. If it is, then the process proceeds to the next iteration of the loop (if any). If the nth service is not of a constant bit rate service type then a further test is carried out to find whether it is a dynamically-priced service offering (step 232 ). If it is a dynamically-priced service offering then a process (step 234 ) is followed to calculate the probability of the delivery of the content file ceasing prematurely. If the nth service offering is not dynamically priced then a test is carried out (step 236 ) to find whether the service offering is a variable bandwidth service offering. If the service offering is a variable bandwidth service offering then a process (step 238 ) is carried out to find the probability of the delivery of the content file ceasing prematurely if that service offering were to be used in delivering the content file. Once the probability of premature cessation of delivery has been found, a test (step 240 ) is carried out to find whether that probability is greater than the acceptable risk set out in the quality of delivery specification received from the agent computer. If the risk is higher than the maximum acceptable risk then the nth service offering is added to a blacklist of services which present a greater risk of premature delivery cessation than the purchaser is prepared to countenance (step 242 ). If the risk is less then the maximum acceptable risk then the next iteration of the loop (if any) is carried out. The process for calculation the probability of premature cessation of delivery when a variable bandwidth offering service is used will now be described in more detail with reference to FIG. 13A . The process begins with a check (step 250 ) to find whether the level of bandwidth currently available (b n ) from this (nth) service offering for a delivery is less than the lowest non zero indicated service in the quality of delivery specification ( FIG. 7 ). If the currently available amount of bandwidth for the delivery is less than the lowest non zero indicated service then the probability of the delivery ceasing prematurely is set to one (step 252 ). If, on the other hand, the amount of bandwidth currently available for a delivery is greater than the lowest non zero indicated service then a calculation of the probability of premature cessation of the delivery is made (step 253 ). That calculation begins with the setting of the value k in the probability distribution function given above to the value found in the network data ( FIGS. 11A and 11B ) and the setting of the parameter T in the function to the duration D of the delivery as given in the quality of delivery specification. The multiplying factor C is then calculated to ensure that the integral of the function over the all possible values of available bandwidth is equal to one. Having substituted the multiplication factor C, the volatility k, and the duration D into the probability density function given above, the resulting function is integrated between a bandwidth of zero and the lowest non zero indicated service in the quality of delivery specification to find the probability of premature delivery cessation. Once the probability of premature delivery cessation has been found then the process ( FIG. 13A ) ends. As mentioned above, when provided with a dynamically-priced service, a rising price will cause the rate at which the user accumulates surplus (where surplus accumulation rate=utility accumulation rate−price of reserved bandwidth) to drop. Normally, the utility accumulation rate per unit of bandwidth drops as the amount of bandwidth provided to the purchaser increases (so the seller of the bandwidth sees diminishing returns with rising bandwidth). Since the allocation of bandwidth is made for a predetermined period, the surplus gained per predetermined period from operating at the higher indicated bandwidths also drops as bandwidth rises (for a given price per unit time per unit bandwidth). Hence, where allocation is made on the basis of allocating a purchaser the service which offers the highest surplus for the next predetermined period and the seller sees diminishing returns with increasing bandwidth, the amount of bandwidth reserved for the purchaser will fall from the highest indicated bandwidth and then through each lower indicated bandwidth in turn as the price of bandwidth rises. But, in some circumstances, a seller would see increasing returns as the amount of bandwidth supplied to a purchaser rises. For example, if the highest indicated bandwidth represents the highest unit value of bandwidth to the purchaser, then the highest surplus will be obtained from receiving the highest level of indicated bandwidth until the price rises above the unit value of bandwidth at that highest level, at which point the other indicated bandwidths will offer a negative surplus. Hence, where allocation is made on the basis of allocating a purchaser the service which offers the highest surplus and the seller sees increasing returns with rising bandwidths, the bandwidth reserved for the purchaser will fall in one step from the highest level of bandwidth to nothing in one step as the price of bandwidth rises. When determining the probability of a delivery made using a variable-bandwidth service ceasing prematurely, it is necessary first to establish the indicated service which can return a positive surplus at higher prices than any other indicated service (since it is cessation of this indicated service that will cause cessation of the delivery as a whole). The process for calculating the probability of premature delivery cessation carried out by the bandwith-broking computer will now be explained with reference to FIG. 13B . The calculation of the risk of premature delivery cessation begins with the setting of a maximum unit value to zero (step 254 ). This is followed by the setting of an indicated service counter to one (step 255 ). Once this has been done, a loop is entered which is iterated as many times as there are non-zero indicated services (in the present case there are three levels—the zero indicated service is referred to herein as m=0, the next highest m=1 and so on to m=3). In each iteration of the loop a set of maximum unit value discovery instructions is carried out (step 256 to step 259 ). The maximum unit value discovery instructions begin with the calculation of the unit value associated with the mth level of indicated service (step 256 ). Once this has been done, a test (step 257 ) is carried out to find whether that unit value is greater than the maximum unit value so far discovered. If the value is not greater than the maximum unit value yet discovered then the next iteration of the loop is carried out. However, if that value is greater than the maximum unit value yet discovered, the maximum unit value is updated to equal the unit value just calculated (step 258 ) and a variable m apex is set to the current value of m (step 259 ). Once the above loop of instructions has been carried out as many times as there are indicated services the maximum marginal price is calculated (step 262 ). The maximum marginal price is the price above which the current delivery will not receive any bandwidth from the dynamically-priced service offering. This price is calculated as for a conventional marginal price (that being the price at which the unit cost exceeds the maximum unit value to the purchaser) but is here adjusted to take account of the fact that a purchaser will be prepared to pay a premium to continue the delivery as the delivery nears its end. The adjusted maximum marginal price is therefore calculated as (U(bm apex )−(ΔSm apex ,0/τ))/bm apex , where τ is the time-period for which the dynamically-priced service offers reservations and ΔSm apex is the penalty associated with the amount of bandwidth provided to the delivery moving from the indicated service which offers the highest unit value to zero bandwidth. This penalty is found in the quality of delivery specification ( FIG. 7 ). It will be understood that the adjustment to the maximum marginal price is that which would occur in the very last reservation period of duration τ required to complete the delivery of the content file. Having calculated the maximum marginal price i.e. the price at which the delivery would cease, a test (step 263 ) is carried out to find whether the current price of bandwidth in the dynamically priced service offering being investigated is greater. If it is greater the delivery will necessarily fail and the probability of premature cessation is set to one (step 264 ). If, on the other hand, the current price is less than the calculated maximum marginal price then a calculation of the probability premature delivery cessation is made (step 265 ). The calculation begins with the substitution of the volatility index k, the duration of the content file D into the probability density distribution given in equation 1 above (but with the random variable being price instead of bandwidth). k and Dare obtained from the network data ( FIG. 11B ) and quality of delivery specification ( FIG. 7 ) respectively. Having substituted those values, the value of C which causes the integral of the probability density function over all possible prices to equal one is calculated. Once that has been calculated, the resulting function is integrated from the maximum marginal price calculated in step 262 up to infinity. The result of that integration is the probability of the delivery ceasing prematurely if this dynamically-priced service offering is used. Once the probability of premature cessation has been calculated in this way the process ends. It is to be understood that the blacklist created by the process described above in relation to FIGS. 12 and 13 might be followed by a random selection of service from the services which are not blacklisted. This would, by itself, represent an improvement of the known methods of service selection. However, in the present embodiment, the bandwidth broker computer further refines its selection of which service to use for a communication. This is done by predicting, for each service which is not blacklisted, the surplus that is likely to be accrued over the duration of the communication. The process will be described below with reference to FIGS. 14 to 22 . The process for selecting the service to be used at the start of the delivery ( FIG. 14 ) is similar to the process for blacklisting certain services in its top level structure. As with the process for creating the blacklist, a loop of instructions (step 274 to step 290 ) is followed which considers each service offering in turn, but rather than calculating the probability of premature delivery cessation if that service should be selected, the session surplus that is likely to be accrued over the duration of the delivery is calculated instead. In step 272 , a selected service array variable is initialised. This array variable has three fields corresponding to an indicated service number (m), the number of the service offering being considered in the current iteration of the loop (this number being the service offering number given in the network data (FIGS. 11 A and 11 B)), and a maximum session surplus variable. These variables are initialised to values zero, nil, and zero respectively. The service selection process ( FIGS. 14 to 23 ) calculates the expected session surplus gained when taking each indicated service from each service offering and updates the selected service array variable when a service (i.e. a given indicated service from a given service offering) is found which offers a session surplus which is greater than the highest session surplus for all the services which have previously been considered. At that time the number of the service offering and the number of the indicated service stored in the selected service array variable are updated to reflect the values associated with the newly favoured service. Hence at the end of the process shown in FIG. 14 the selected service array variable contains an indication of the service to be used at the start of the delivery together with an indication of the session surplus that is likely to be accrued from the use of that service to make the delivery. On each iteration of the loop of instructions (steps 276 to step 290 ), a test (step 283 ) is carried out to find whether the service offering currently being considered is on the blacklist created in accordance with the process described above. If the service is on that blacklist then the current iteration ends and the next service offering (if any) is considered. In this way, it is ensured that the service represented in the selected service array variable at the end of the initial service selection process ( FIG. 14 ) will not be a service provided by a blacklisted service offering. If, the test (step 280 ) to find whether the service offering currently being considered is a constant bit rate service offering is positive then a calculation of the session surplus to be expected from each indicated service when taken from a constant bit-rate service offering over the duration of the delivery is calculated in step 282 . This calculation will now be explained in more detail with reference to FIG. 15 . The calculation of session surplus for a constant bit rate service offering is carried out for each of the indicated services in the quality of delivery specification in turn. In this process, the rate of surplus accumulation (which equals the rate of utility accumulation minus the rate of expenditure) is multiplied by the duration of the content file as given in the quality of delivery specification (step 302 ). A test is then carried out to find whether the session surplus calculated is greater than the maximum session surplus so far found (step 304 ). If the session surplus is the greatest so far found then the selected service array variable is updated accordingly (step 306 ). If, on the other hand, the session surplus is less than that found for a previously considered service then a further iteration of the loop is carried out for each of the remaining as yet unconsidered indicated services. In order to provide a measure of the session surplus obtained when a variable-bandwidth service or dynamically-priced service it is supposed that: i) the network will continue to provide the initially selected service for the first half of the delivery; ii) at the mid-point of the duration of the delivery, an opportunity to select a service for the second half of the delivery will be given; and iii) once the service selection has been made, the network will continue to provide that service for the second half of the delivery. It is to be noted that, if the proposed change of service at the mid-way point of the delivery was supposed to be made on the basis of the same criteria as the initial service selection, then the proposed service selection would have to calculate probabilities of service changes that might take place three quarters of the way through the delivery and those probabilities would in turn depend on probabilities of various service changes seven eights of the way through the delivery and so on. In the present embodiment the inventors have overcome this problem by assuming that the mid-way point service selection will be made on different criteria—the criteria used is that the service which maximises the instantaneous surplus accumulation rate at that time will be chosen (a penalty is also taken into account here—this is explained below). Furthermore, it is assumed that the service will be maintained throughout the second half of the session—so an equivalent assumption is that the service which maximises the penalised second half surplus will be chosen. As mentioned above, the penalised surplus is considered rather than the surplus itself. The penalised surplus is a surplus value which includes a utility penalty if the indicated service chosen for the second half differs from that chosen for the first half. That expected penalised second half surplus is found by assuming that the indicated service which maximises the penalised second half surplus will be chosen for the second half of the delivery. The problem then is that the surplus for the different services cannot be found directly since the price of a dynamically-priced service offering or the bandwidth available from a variable-bandwidth service offering at the mid-way point cannot be known at the start of the delivery. In the present embodiment, the inventors have overcome that problem by calculating for any variable bandwidth offering, the ranges of available bandwidth which would lead to a given service providing the maximum penalised second half surplus (i.e. which would lead to that service being selected for the second-half). The probability of the bandwidth then being in that range can be found from the above probability density function. By summing the products of the probability of getting a given surplus and the amount of that surplus, an expected second half surplus for the variable-bandwidth service offering is obtained. A similar calculation is made for the dynamically-priced service offerings. It is further assumed that the service offering chosen for the second half will be that which offers the greatest expected penalised second half surplus. It is that greatest expected penalised second half surplus which is used in the calculation of expected session surplus for each of the non-blacklisted candidate first half services. Also, note that if no service offerings are blacklisted then, in the case of the cable network, there are 3*3=9 possible services for the first half (the product of the number of service offerings and the number of indicated services). Each of those requires the 9 possible services for the second half to be considered. This represents a similar amount of processing to comparing 81 service combinations. If, instead of assuming a single change of service point at the half-way point, the session surplus was predicted by a series of service change points at 30 second intervals, then the number of possible combinations of services used in a delivery lasting for a number (P, say) of 30 second reservation periods would be 81 P . For most deliveries this leads to an astronomical number of combinations to be considered—hence the problem of predicting the session surplus might be thought intractable. The problem increases in the case of variable bandwidth services where the bandwidth supplied to a delivery may vary in a time period of a similar length to the time taken to send a packet at the transmission rate of the link that leads from the store where the packet is held. The calculation of the expected session surplus where a dynamically-priced service offering is used (FIG. 16 —which corresponds to step 285 in FIG. 14 ) carries out 10 a loop of instructions (steps 324 to 335 ) for each of the indicated services in the quality of delivery specification ( FIG. 7 ). The loop of instructions (steps 324 to 335 ) begins with the calculation of the surplus which results from the mth indicated service being provided to the purchaser for the first half of the delivery (step 324 ). Note that $ n,0 refers to the price of bandwidth in the nth service offering at the start of the delivery. Note that the subscript i in the expression S i (m,n) indicates that the surplus calculated in step 324 relates to the initial half of the delivery. Once the surplus for the first half of the delivery has been found, a calculation (step 326 ) is carried out to find the expected penalised second half surplus that will be obtained in the second half of the delivery. Note that the caret above the ‘S’ indicates penalisation. Penalisation will be explained in more detail below with reference to FIG. 18 . Once the surpluses for the first half and second half have been found, the two are added together to give the expected session surplus if the mth indicated service is taken from the nth service offering. Once this sum has been calculated, it is compared to the maximum session surplus found so far (step 330 ). If the expected session surplus is greater than the maximum session surplus so far found then the selected service array variable is updated with the service (m,n) currently being considered, and the associated expected session surplus (step 332 ). The loop of instructions is then repeated for any indicated services that have not yet been considered. Once all the indicated services have been considered then the consideration of the dynamically-priced service offering currently being considered ends (step 336 ). Where the initially selected service offering is a variable bandwidth service offering then the process for calculating the expected session surplus ( FIG. 17 ) performed by the bandwidth broker computer ( FIG. 16B ) is identical to the process for calculating the expected session surplus where a dynamically-priced service offering is being considered save for one extra processing step. This extra processing step is the introduction of a test (step 332 ) at the start of each iteration of the loop of instructions which finds whether the currently selected variable bandwidth service offering is offering sufficient bandwidth to support the indicated service being considered in the current iteration of the loop of instructions (steps 322 to 335 ). If the service offering would not be able to provide a service with a level of bandwidth as great as that needed for the currently indicated service then the possibility of using that service is in effect discounted by jumping to the next iteration of the loop of instructions (steps 322 to 335 ). The calculation of expected penalised second half surplus performed by the bandwidth broker computer (as part of the calculation of expected session surplus (step 328 in FIGS. 16 and 17 )) will now be explained with reference to FIGS. 18 to 23 . At the top level the calculation of expected penalised second half surplus consists of the steps shown in FIG. 18 . Note that m′ and n′ in the Figures refer respectively to the indicated service and service offering chosen for the second half of the delivery. It will be seen that the process comprises the repeated iteration of a loop of instructions (steps 344 to 361 ), once for each of the service offerings which might be used to provide service for the delivery during the second half of that delivery. The consideration of each service offering involves the consideration of each indicated service when provided by that service offering. The loop of instructions comprises a first part in which the expected penalised second half surplus is calculated for the service offering currently being considered (steps 344 to 354 ), and a second half (steps 356 and 358 ) in which the maximum of the expected penalised second half surpluses calculated so far is found. FIG. 19A illustrates the process carried out by the bandwidth broker computer to determine the expected penalised second half surplus where a dynamically-priced service offering is used for the second half of the delivery. To this end a block of instructions (step 372 to 380 ) is carried out for each of the indicated services taken from the n′th dynamically-priced service offering. That block of instructions (step 372 to 380 ) begins with the calculation with the probability of the m′th indicated service being selected given assuming that the n′th dynamically-priced service offering is used for the second half of the delivery. This step ( 372 ) will now be explained in more detail with reference to FIGS. 19B and 19C below. A process for calculating a price reaction service sequence ( FIG. 19B ) begins with the initialisation of a price reaction service sequence array (which has a number of elements which is equal to the number of indicated services within the dynamically-priced service offering currently being considered (including the ‘zero’ indicated service)) such that each of the elements is set to zero except for the first which is set to the number of indicated services (step 190 ). This is followed by the initialisation of a step count variable to one (step 192 ). Were the price of the n′th service offering to be set to zero then the indicated service which offered the highest instantaneous surplus would necessarily be that associated with the highest bandwidth. Hence, the first element of the array is set to the number of the highest indicated service. The reaction to a rising price will then pass through one or more of the other indicated services until the price reaches such a level (this was calculated as $apex earlier) that the purchaser chooses the zeroth indicated service. It is this sequence of steps that the buyer array intends to record. Having initialised the step count variable, a step_start variable is set equal to the number of the highest indicated service and a step_finish variable is set to the second highest indicated service (step 194 ). Thereafter, in step 196 , the unit value of the indicated service with the highest bandwidth is calculated (step 196 ). It is to be noted that the unit value rises and falls with the instantaneous surplus accumulation rate in the present case since the price of the variable-bandwidth service is fixed. Next, the unit value associated with the indicated service having the current value of the step_finish variable as an index number is found (step 198 ). A test is then carried out to find out whether the unit value at the step_finish is less than the unit value at the step_start (step 200 ). If it is, then a purchaser operating at the m′th indicated service would not choose to use the (m′−1)th indicated service since he or she would prefer the m′th indicated service. If, however, the opposite is true then a rising price will cause the purchaser to purchase the (m′−1)th indicated service in preference to the mth indicated service. In that case, a step update block of instructions (step 202 to step 208 ) is carried out. That block of instructions begins with the incrementing of the step count variable to indicate that another step in the purchasers price reaction sequence has been found (step 202 ). This is followed by an entry being made in the buy array to indicate that the (m′−1)th indicated service would be visited by a purchaser in reaction to a rising price (step 204 ). Thereafter, the marginal price at which the purchaser would move from the mth indicated service to the (m′−1)th indicated service is found (step 206 ). As when calculating $apex, account may be taken of the undesirability of changing indicated service if only a short period of the delivery remains. The block of instructions finishes with the setting of the step_start variable to the current value of step_finish (step 208 ) thereby causing the following iteration of the loop to relate to the next step in the users price reaction sequence. The loop of instructions (step 198 to step 208 ) is then repeated until the step considered is that which causes the purchaser to cease purchasing bandwidth altogether. Once the reaction of the purchaser to rising price in a dynamically-priced service offering has been calculated, it is possible to calculate probability of a purchaser choosing a given indicated service from a dynamically-priced service offering. The process for doing this is illustrated in FIG. 19C . The process begins with the initialisation of an indicated service index number to zero (step 390 ). This is followed by an initialisation of a selection probability array (which again has as many elements as there are indicated services) to zero (step 392 ). A loop of instructions (step 394 to step 402 ) is then entered which is repeated as many times as there are steps in the purchaser's price reaction sequence. In the first of a block of instructions so repeated, the probability of selecting the member of the purchasers price reaction sequence currently being considered is found. This is calculated by substituting half the duration of the delivery as the time variable in the probability density function which represents the price in the n′th service offering and then integrating that function between the marginal price which causes a purchaser (seeking to maximise the penalised second half surplus) to drop to the indicated service currently being considered and the marginal price which causes the purchaser to drop from the indicated service currently being considered (step 396 ). This calculation is immediately followed by a calculation of the likely price of the n′th service offering given that the price has caused the purchaser to move to the indicated service currently being considered (step 398 ). Returning now to FIG. 19A , a test (step 374 ) is carried out to find out whether the indicated service currently being considered would be adopted by a purchaser in any circumstance. If it would not then the process continues to the next iteration of the loop (if any). If, on the other hand, the m′th indicated service is included within the purchasers price reaction sequence then the expected second half surplus is calculated (step 376 ) and then modified by the addition of the product of the probability of the m′th indicated service being selected and the penalised second half surplus gained were that indicated service to be provided for the duration of the second half (step 380 ). The price used in this calculation is the expected price given that price changes have caused the purchaser to select the m′th indicated service as calculated above ( FIG. 19C ). The above process is then repeated for each of the M′th services until an expected penalised second half surplus has been calculated. The process for calculating the expected second half surplus gained from the variable bandwidth service offering ( FIGS. 20A , 20 B and 20 C) is similar to that set out above for the dynamically-priced service. However, the reaction sequence found in this case is a reaction to increasing bandwidth rather than a reaction to increasing price. Note that in the Figures $ n′ refers to the price of bandwidth in the service offering being considered for the second half of the delivery. Having obtained the greatest expected penalised second half surplus by the processes illustrated in FIGS. 18 to 20C , the bandwidth broker computer is able to select that service which maximises the expected session surplus. Because of the penalties incurred for choosing a lower indicated service at the half-way point, an initial service which matches the users combined requirements for stability and rate as represented by the utility penalties and the utility of the indicated services is selected. After a period of 30 seconds, an in-delivery service selection is carried out. This service selection is carried out identically to the initial service selection described above save for a penalty being added (in step 462 in FIG. 22 ) to those subsequent service selections in accordance with the penalty set out by the purchaser in the quality of delivery specification ( FIG. 7 ) and the calculations involving the duration of the delivery in the initial service selection being replaced with calculations involving the duration of the remainder of the delivery in subsequent service selections. Returning now to FIG. 8 , having determined the service to be applied to the content file transfer to the requesting user (in either the initial evaluation or subsequent re-evaluations), the agent computer A 1 sends (step 8 ) a message indicating the source and destination IP addresses and TCP ports of the content file transfer and the Diff-Serv marking associated with the selected indicated service to the marker 164 . In the meantime, the caching server C 1 sets up a streaming session with the user's PC 152 . The caching server divides the content file into packets and starts sending (step 10 ) those packets to the user's PC 152 via the marker 164 . Once the marker 164 has received the Diff-Serv marking message from the bandwidth broker computer B 1 , it recognises packets belonging to the content file transfer (the IP address and User Datagram Protocol (UDP) port in the marking instruction will match the corresponding parameters in packets belonging to the content file transfer—note that, since it is operating as a transparent cache, the caching server operates to use the origin server's address as the source address of the packets). The marker marks packets so recognised with a Diff-Serv codepoint that corresponds to the selected bandwidth. The marked packets are forwarded to the CMTS 146 which will schedule the packets sent from it in accordance with the diff-serv codepoints they contain. It will be seen how the above described embodiment enables a single quality of delivery specification to be used in the selection of a suitable service type, even when the selection is between variable bandwidth and variable price service types. In particular, on the basis of the quality of delivery specification data ( FIG. 4 ), the bandwidth broker computer B 2 of the DSL network running the process explained above is able to select a service from either the variable price service offering or the constant bit-rate service offering. Also, the same process carried out by the bandwidth broker computer B 1 of the cable network is, on the basis of the same quality of delivery specification, able to choose an indicated service from one of the three variable bandwidth service offerings. A large number of variations might be made to the above embodiment without preventing it achieving the benefits of the present invention. These variations include (but are not limited to): i) Instead of the values k and C which parameterise a predetermined form of probability density function, the local/regional network operator might supply data which tabulates the value of a probability density function obtained from empirical observations of the bandwidth or price behaviour of each service offering; ii) a single bandwidth broking computer could carry out the process for both the cable network and the DSL network; iii) a single quality of delivery policy ( FIG. 4 ) and a single agent computer could be used for different access networks of similar or different technologies; iv) The further into a session premature termination occurs, the more negative impact it has. In preferred embodiments, the termination penalty, ΔS m,0 , varies with time. E.g. ΔS m,0 =a m T+b m . To allow for more accurate approximations of this kind in the future embodiments might allow for the formula to be specified (in addition to the specification of any parameters such as a and/or b). Alternatively the formula may be stored with curves used to determine the values of a b rm and b brm ; v) in the above-described embodiments the quality of delivery is assumed to accord with the amount of capacity provided to a delivery at a bottleneck node in that delivery. In other embodiments, the quality of delivery might be judged by the delay in delivering packets form the caching computer to the customer's PC. In a similar way to the way the above embodiment chooses a network service which offers a desired level of stability in supplied bandwidth, in such other embodiments, the network service chosen could be that which offers a suitable variation in the delay experienced by packets in the delivery—embodiments might also take both measures of quality of delivery into account; vi) in the above embodiment, the agent, cache and bandwidth broker computers were separate from one another. In alternative embodiments, any two or all of these functions could be carried out by a single computer; vii) in the above embodiment, the available bandwidth was communicated as part of the service offering data (FIGS. 11 A and 11 B)—it could alternatively be communicated by means of explicit congestion notification marks set in the packets of the delivery by routers experiencing congestion. Price could also be communicated in this way.

A method of selecting a suitable service for the delivery of a communication across an integrated network is disclosed. Before now, users had to select the service that best suited their needs at the time of each delivery. By providing a computer programmed to act as a purchasing agent with data indicating the desirability of stability in the network service (that data representing the price the user is prepared to pay for stability) an automatic selection of the service to be provided to the communication is enabled. An embodiment is described in which different degrees of stability are given to different content file deliveries in dependence on the importance attached to the recipient by a content provider. The invention could equally be used to provide an appropriate services for many different types of network traffic.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 12/371,078, filed on Feb. 13, 2009, which is a continuation of International Application No. PCT/CN2007/070384, filed on Jul. 30, 2007. The International Application claims priority to Chinese Patent Application No. 200610115381.3, filed on Aug. 15, 2006. The afore-mentioned patent applications are hereby incorporated by reference in their entireties. FIELD OF THE INVENTION The present invention relates to the field of telecommunications and in particular to a data processing technique and system. BACKGROUND OF THE INVENTION Existing General Package Radio Service (GPRS)/Universal Mobile Telecommunications System (UMTS) techniques employ network architecture similar to second-generation wireless communication systems, including UMTS Territorial Radio Access Network (UTRAN), GSM/EDGE Radio Access Network (GERAN), Core Network (CN) and Mobile Station (MS), as illustrated in FIG. 1 . The GERAN/UTRAN implements all wireless related functions, and the CN handles all voice calls and data connections in GPRS/UMTS and implements switching and routing functions with external networks. Logically the CN can be divided into a Circuit Switched (CS) domain and a Packet Switched (PS) domain, supporting voice and data services respectively. The CS domain includes nodes such as Mobile Switching Center (MSC) server, Media Gateway (MGW) and Gateway Mobile Switching Centre (GMSC) server. The MSC server transmits control plane data of the CS domain, and implements functions such as mobility management, call control and authentication encryption; the GMSC server handles call control and mobility control in the control plane for a GMSC; the MGW handles transmission of user plane data. The PS domain includes nodes such as Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN). The GGSN is an interface to interact with external networks. Also, as a user plane anchor (i.e. user plane anchor network element) between a GERAN and a UTRAN, the GGSN transmits data of the user plane. Having a position similar to the MSC server in the CS domain, the SGSN implements functions such as routing forwarding, mobility management, session management and user information storage. Home Location Registers (HLRs) are used in both the CS domain and the PS domain to store user subscription information. In existing 3GPP protocols, user plane processing of UMTS is based on a two-tunnel mechanism illustrated as in FIG. 2 . In UMTS, the user plane processing is between a Radio Network Controller (RNC, a network element of a UTRAN, used to control wireless resources of the UTRAN) and an SGSN, and between an SGSN and a GGSN, over an Iu interface and a Gn interface respectively. For the two-tunnel mechanism, an SGSN handles both the user plane and the control plane; therefore control plane processing and user plane processing are not separate. With the introduction of High Speed Packet Access (HSPA) and IP Multimedia Subsystem (IMS), there will be a significant data flow growth in future 3GPP network. At present, in order to improve data processing capability of UMTS, a new UMTS user plane processing mechanism, i.e. direct-tunnel mechanism, has been proposed. As illustrated in FIG. 2 , in this mechanism, the user plane processing of UMTS is between an RNC and a GGSN, without an SGSN. For the direct-tunnel mechanism, an SGSN handles functions of the control plane only; therefore control plane processing and user plane processing are separate. Now with reference to FIGS. 3 to 6 , the processes of handover or change between a GERAN and a UTRAN are illustrated hereinafter. At present, the process of handing over from a GERAN to a UTRAN according to the protocol 43.129 is illustrated as in FIG. 3 : step S 301 : a source Base Station Subsystem (BSS) decides to initiate a PS handover; step S 302 : the source BSS sends a PS handover request message to an old SGSN, i.e. 2G SGSN; step S 303 : the 2G SGSN sends a forward relocation request message to a new SGSN, i.e. 3G SGSN; step S 304 : the 3G SGSN builds a relocation request message and sends the message to a target RNC; step S 305 : the target RNC sends a relocation request acknowledge message to the 3G SGSN; step S 306 : the 3G SGSN sends a forward relocation response to the 2G SGSN; step S 307 : the 2G SGSN receives an IP packet from a GGSN and sends the IP packet to an MS via the source BSS; step S 308 : the 2G SGSN forwards the IP packet to the target RNC via the 3G SGSN; step S 309 : the 2G SGSN sends a PS handover request acknowledge message to the source BSS; step S 310 : the MS sends a handover to UTRAN complete message to the target RNC; step S 311 : the target RNC sends a relocation complete message to the 3G SGSN; step S 312 : the 3G SGSN sends an update PDP context request message to the GGSN; step S 313 : the GGSN returns an update PDP context response message to the 3G SGSN; The process of handing over from a UTRAN to a GERAN is illustrated as in FIG. 4 : step S 401 : a source RNC decides to initiate a PS handover; step S 402 : the source RNC sends a relocation request message to an old SGSN, i.e. 3G SGSN; step S 403 : the 3G SGSN sends a forward relocation request message to a new SGSN, i.e. 2G SGSN; step S 404 : the 2G SGSN builds a PS handover request message and sends the message to a target BSS; step S 405 : the target RNC sends a PS handover request acknowledge message to the 2G SGSN; step S 406 : the 2G SGSN sends a forward relocation response message to the 3G SGSN; step S 407 : the 3G SGSN receives an IP packet from a GGSN and sends the IP packet to an MS via the source RNC; step S 408 : the 3G SGSN sends a relocation command message to the source RNC; step S 409 : the source RNC forwards the IP packet to the 3G SGSN, the 3G SGSN forwards the IP packet to the 2G SGSN, and the 2G SGSN forwards the IP packet to the target BSS; step S 410 : the target BSS sends a PS handover complete message to the 2G SGSN; step S 411 : the 2G SGSN sends an update PDP context Request message to the GGSN; step 412 : the GGSN returns an update PDP context response message to the 2G SGSN; At present, the process of changing from a GERAN to a UTRAN according to the protocol 23.060 is illustrated as in FIG. 5 : step S 501 : an MS decides to perform an inter-system change; step S 502 : the MS sends a routing area update request message to a new SGSN, i.e. 3G SGSN; step S 503 : the 3G SGSN sends an SGSN context request message to an old SGSN, i.e. 2G SGSN, to obtain user context; step S 504 : the 2G SGSN returns an SGSN context response message to the 3G SGSN, and carries the user context information in the context response message; step S 505 : the 3G SGSN sends an SGSN context acknowledge message to the 2G SGSN, informing the 2G SGSN that the 3G SGSN is ready to receive data packets; step S 506 : the 2G SGSN duplicates a buffered data packet and forwards to the 3G SGSN; step S 507 : the 3G SGSN sends an update PDP context request message to a GGSN; step S 508 : the GGSN returns an update PDP context response to the 3G SGSN; step S 509 : the 3G SGSN returns a routing area update accept message to the MS; step S 510 : the MS returns a routing area update complete message to the 3G SGSN; step S 511 : the MS sends a service request message to the 3G SGSN; step S 512 : Radio Access Bearer (RAB) Assignment procedure is performed between the 3G SGSN and an RNC, thereby establishing a RAB; At present, the process of changing from a UTRAN to a GERAN according to the protocol 23.060 is illustrated as in FIG. 6 : step S 601 : an MS decides to perform an inter-system change; step S 602 : the MS sends a routing area update request message to a new SGSN, i.e. 2G SGSN; step S 603 : the 2G SGSN sends an SGSN context request message to an old SGSN, i.e. 3G SGSN, to obtain user context; step S 604 : the 3G SGSN sends an SRNS context request message to a source RNC; step S 605 : the source RNC returns an SRNS context response message to the 3G SGSN, stops sending downlink data to the MS, and buffers the data; step S 606 : the 3G SGSN returns an SGSN context response message to the 2G SGSN, and carries the user context information in the context response message; step S 607 : the 2G SGSN sends an SGSN context acknowledge message to the 3G SGSN, informing the 3G SGSN that the 2G SGSN is ready to receive data packets; step S 608 : the 3G SGSN sends an SRNS data forward command to the source RNC, the source RNC duplicates a buffered data packet and forwards to the 3G SGSN; step S 609 : the 3G SGSN forwards the data packet to the 2G SGSN step S 610 : the 2G SGSN sends an update PDP context request message to a GGSN; step S 611 : the GGSN returns an update PDP context response to the 2G SGSN; step S 612 : the 2G SGSN returns a routing area update accept message to the MS; step S 613 : the MS returns a routing area update complete message to the 2G SGSN; In the processes as illustrated in FIGS. 3 to 6 , the user plane data processing when a handover or change from a GERAN to a UTRAN takes place is that, a 3G SGSN forwards data that are forwarded to by a 2G 3GSN to a target RNC; and the user plane data processing when a handover or change from a UTRAN to a GERAN takes places is that, a 3G SGSN forwards data that is forwarded to by a source RNC to a 2G SGSN. However, in a direct-tunnel mechanism where a 3G SGSN no longer performs user plane data processing, data forwarding can not be done via a 3G SGSN. Therefore, the existing data processing method when a handover or change between a GERAN and a UTRAN takes place does not fit the direct-tunnel mechanism. SUMMARY OF THE INVENTION A data processing method and system are provided by the present invention, in order to implement data forwarding in a direct-tunnel mechanism when a handover or change between a 2G system and a 3G system takes place. The present invention provides a data processing method. The method includes: receiving, by a user plane anchor network element, data forwarded by a source data forwarding network element; and forwarding, by the user plane anchor network element, the data to a target side processing network element. The present invention further provides a data processing method. The method includes: receiving, by a user plane anchor network element, an instructive message, and sending data to at least one of a source data forwarding network element and a target side processing network element; and updating, by the user plane anchor network element, user plane routing, and sending the data to the target side processing network element as instructed in the message according to the updated user plane routing. The present invention provides a data processing system, including a source data forwarding network element, a user plane anchor network element and a target side processing network element, wherein the user plane anchor network element is provided with a receipt unit adapted to receive data forwarded by the source data forwarding network element, and a sending unit adapted to forward the received data to the target side processing network element. The present invention provides a user plan anchor network element, including a receipt unit and a sending unit, wherein the receipt unit is adapted to receive data forwarded by the source data forwarding network element; and the sending unit is adapted to forward the received data to the target side processing network element. With the data processing methods in the direct-tunnel mechanism when a handover or change between a GERAN and a UTRAN takes place, a GGSN can buffer data forwarded by a source data forwarding network element and then send the data to a target side processing network element; alternatively, the GGSN can send the data forwarded by the source data forwarding network element directly to the target side processing network element. The problem that the data processing method in the conventional art is not applicable in the direct-tunnel mechanism is solved and normal forwarding of service data in the direct-tunnel mechanism when a handover or change between a GERAN and a UTRAN takes place is achieved. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates network architecture of GPRS/UMTS; FIG. 2 illustrates user plane processing in the conventional art; FIG. 3 is a flow chart of a data processing method when a handover from a GERAN to a UTRAN takes place according to the protocol 43.129; FIG. 4 is a flow chart of a data processing method when a handover from a UTRAN to a GERAN takes place according to the protocol 43.129; FIG. 5 is a flow chart of a data processing method when a change from a GERAN to a UTRAN takes place according to the protocol 23.060; FIG. 6 is a flow chart of a data processing method when a change from a UTRAN to a GERAN takes place according to the protocol 23.060; FIG. 7 is a flow chart of a data processing method when a handover from a GERAN to a UTRAN takes place according to a first embodiment of the present invention; FIG. 8 is a flow chart of a data processing method when a handover from a UTRAN to a GERAN takes place according to a first embodiment of the present invention; FIG. 9 is a flow chart of a data processing method when a change from a GERAN to a UTRAN takes place according to a first embodiment of the present invention; FIG. 10 is a flow chart of a data processing method when a change from a UTRAN to a GERAN takes place according to a first embodiment of the present invention; FIG. 11 illustrates network architecture of an evolved packet core network in the conventional art; FIG. 12 is a flow chart of a data processing method when a handover from a GERAN to a UTRAN takes place according to a second embodiment of the present invention; FIG. 13 is a flow chart of a data processing method when a handover from a UTRAN to a GERAN takes place according to a second embodiment of the present invention; FIG. 14 is a flow chart of a data processing method when a change from a GERAN to a UTRAN takes place according to a second embodiment of the present invention; FIG. 15 is a flow chart of a data processing method when a change from a UTRAN to a GERAN takes place according to a second embodiment of the present invention; FIG. 16 is a flow chart of a data processing method when a handover from a GERAN to a UTRAN takes place according to a third embodiment of the present invention; FIG. 17 is a flow chart of a data processing method when a handover from a UTRAN to a GERAN takes place according to a third embodiment of the present invention; FIG. 18 is a flow chart of a data processing method when a change from a GERAN to a UTRAN takes place according to a third embodiment of the present invention; FIG. 19 is a flow chart of a data processing method when a change from a UTRAN to a GERAN takes place according to a third embodiment of the present invention; and FIG. 20 is a structural diagram of a data processing system provided in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS Exemplary embodiments of the present invention will be described in details hereinafter with reference to the drawings. In the specification multiple embodiments of data processing method are provided. A first method is described hereinafter. The method includes: when a change or handover from a GERAN to a UTRAN takes place, a 2G SGSN forwards a data packet to a GGSN, and the GGSN forwards the data packet to a target RNC; when a handover from a UTRAN to a GERAN takes place, a source RNC forwards a data packet to a GGSN, the GGSN forwards the data packet to a 2G SGSN, and the 2G SGSN forwards the data packet to a target BSS. Now refer to FIG. 7 . As illustrated in FIG. 7 , a data processing method when a handover from a GERAN to a UTRAN takes place includes: step S 701 : a source BSS decides to initiate a handover; step S 702 : the source BSS sends a handover request message to an old SGSN, i.e. 2G SGSN; step S 703 : the 2G SGSN sends a forward relocation request message to a new SGSN, i.e. 3G SGSN; step S 704 : the 3G SGSN builds a relocation request message, and sends the message to a target RNC; step S 705 : the target RNC sends a relocation request acknowledged message to the 3G SGSN; step S 706 : the 3G SGSN sends an update PDP context request message to a GGSN, to request to change user plane routing from the GGSN to the 3G SGSN; step S 707 : the GGSN returns an update PDP context response to the 3G SGSN; step S 708 : the 3G SGSN sends a forward data request to the GGSN, to request the GGSN to assign a data forwarding tunnel for data forwarding; step S 709 : the GGSN returns a forward data response message to the 3G SGSN, assigns a data forwarding tunnel identifier to the data forwarding tunnel and carries the data forwarding tunnel identifier in the response message to the 3G SGSN, the data forwarding tunnel identifier includes IP address and TEID (Tunnel End Point Identifier); step S 710 : the 3G SGSN sends a forward relocation response message to the 2G SGSN, a data forwarding tunnel identifier carried in the message is the data forwarding tunnel identifier of the GGSN; step S 711 : the 2G SGSN receives a data packet from the GGSN, and sends the data packet to an MS via the source BSS; step S 712 : for data of a lossless service, the 2G SGSN forwards the data packet to the GGSN according to the data forwarding tunnel identifier carried in the forward relocation response message sent by the 3G SGSN, the GGSN buffers the data packet after receiving the data packet forwarded by the 2G SGSN; step S 713 : the 2G SGSN sends a handover request acknowledge message to the source BSS; step S 714 : the MS sends a handover to UTRAN complete message to the target RNC; step S 715 : the target RNC sends a relocation complete message to the 3G SGSN; step S 716 : the 3G SGSN sends an update context request message to the GGSN; step S 717 : the GGSN returns an update context response message to the 3G SGSN; step S 718 : the GGSN forwards the buffered forwarded data packet to the target RNC. Now with reference to FIG. 8 , a data processing method when a handover from a UTRAN to a GERAN takes place includes: step S 801 : a source RNC decides to initiate a handover; step S 802 : the source RNC sends a relocation request message to an old SGSN, i.e. 3G SGSN; step S 803 : the 3G SGSN sends a forward relocation request message to a new SGSN, i.e. 2G SGSN; step S 804 : the 2G SGSN builds a handover request message, and sends the message to a target BSS; step S 805 : the target BSS sends a handover request acknowledged message to the 2G SGSN; step S 806 : the 2G SGSN sends a forward relocation response message to the 3G SGSN; step S 807 : the 3G SGSN sends a forward data request to a GGSN, to request the GGSN to assign a data forwarding tunnel for data forwarding; step S 808 : the GGSN returns a forward data response message to the 3G SGSN, assigns a data forwarding tunnel identifier to the data forwarding tunnel and carries the data forwarding tunnel identifier in the response message to the 3G SGSN; step S 809 : the 3G SGSN receives a data packet from the GGSN, and sends the data packet to an MS via the source RNC; step S 810 : the 3G SGSN sends a relocation command message to the source RNC, a data forwarding tunnel identifier carried in the message is the data forwarding tunnel identifier of the GGSN; step S 811 : for data of a lossless service, the source RNC forwards the data packet to the GGSN according to the data forwarding tunnel identifier carried in the relocation command message sent by the 3G SGSN, the GGSN buffers the received data packet; step S 812 : the target BSS sends a handover complete message to the 2G SGSN; step S 813 : the 2G SGSN sends an update context request message to the GGSN; step S 814 : the GGSN returns an update context response message to the 2G SGSN; step S 815 : the GGSN forwards the buffered forwarded data packet to the 2G SGSN. Now with reference to FIG. 9 , a data processing method when a change from a GERAN to a UTRAN takes place includes: step S 901 : an MS decides to initiate an intersystem change; step S 902 : the MS sends a routing area update request message to a new SGSN, i.e. 3G SGSN; step S 903 : the 3G SGSN sends an SGSN context request message to an old SGSN, i.e. 2G SGSN, to obtain user context; step S 904 : the 2G SGSN returns an SGSN context response message to the 3G SGSN, and carries the user context information in the message; step S 905 : the 3G SGSN sends an update PDP context request message to a GGSN, to request to change user plane routing from the GGSN to the 3G SGSN; step S 906 : the GGSN returns an update PDP context response to the 3G SGSN; step S 907 : the 3G SGSN sends a forward data request message to the GGSN, to request the GGSN to assign a data forwarding tunnel for data forwarding; step S 908 : the GGSN returns a forward data response message to the 3G SGSN, assigns a data forwarding tunnel identifier to the data forwarding tunnel, and carries the data forwarding tunnel identifier in the response message to the 3G SGSN; step S 909 : the 3G SGSN sends an SGSN context acknowledge message to the 2G SGSN, informing the 2G SGSN that the 3G SGSN is ready to receive data packets, a data forwarding tunnel identifier carried in the message is the data forwarding tunnel identifier of the GGSN; step S 910 : the 2G SGSN duplicates a buffered data packet and forwards to the GGSN according to the data forwarding tunnel identifier carried in the SGSN context acknowledge message sent by the 3G SGSN, the GGSN buffers the received forwarded data packet; step S 911 : the 3G SGSN returns a routing area update accept message to the MS; step S 912 : the MS returns a routing area update complete message to the 3G SGSN; step S 913 : the MS returns a service request message to the 3G SGSN; step S 914 : RAB assignment procedure is performed between the 3G SGSN and an RNC, thereby establishing RAB; step S 915 : the 3G SGSN sends an update context request message to the GGSN; step S 916 : the GGSN returns an update context response message to the 3G SGSN; step S 917 : the GGSN forwards the buffered forwarded data packet to the target RNC. Now with reference to FIG. 10 , a data processing method when a change from a UTRAN to a GERAN takes place includes: step S 1001 : an MS decides to initiate an intersystem change; step S 1002 : the MS sends a routing area update request message to a new SGSN, i.e. 2G SGSN; step S 1003 : the 2G SGSN sends an SGSN context request message to an old SGSN, i.e. 3G SGSN, to obtain user context; step S 1004 : the 3G SGSN sends an SRNS context request message to a source RNC; step S 1005 : the source RNC returns an SRNS context response message to the 3G SGSN, stops sending downlink data to the MS, and buffers the data; step S 1006 : the 3G SGSN returns an SGSN context response message to the 2G SGSN, and carries the user context information in the message; step S 1007 : the 2G SGSN sends an SGSN context acknowledge message to the 3G SGSN, informing the 3G SGSN that the 2G SGSN is ready to receive data packets; step S 1008 : the 3G SGSN sends a forward data request to a GGSN, to request the GGSN to assign a data forwarding tunnel for data forwarding; step S 1009 : the GGSN returns a forward data response message to the 3G SGSN, assigns a data forwarding tunnel identifier to the data forwarding tunnel, and carries the data forwarding tunnel identifier in the response message to the 3G SGSN; step S 1010 : the 3G SGSN sends an SRNS data forward command to the source RNC, a data forwarding tunnel identifier carried in the message is the data forwarding tunnel identifier of the GGSN, the source RNC duplicates a buffered data packet and forwards to the GGSN, the GGSN buffers the forwarded data packet; step S 1011 : the 2G SGSN sends an update PDP context request message to the GGSN; step S 1012 : the GGSN returns an update PDP context response message to the 2G SGSN; step S 1013 : the GGSN forwards the buffered forwarded data packet to the 2G SGSN; step S 1014 : the 2G SGSN returns a routing area update accept message to the MS; step S 1015 : the MS returns a routing area update complete message to the 2G SGSN. In order to enhance its competitive advantages in the future, the 3GPP is studying new evolved network architecture, including System Architecture Evolution (SAE) and Long Term Evolution (LTE) access network. The evolved access network is known as E-UTRAN, network architecture of an evolved packet core network, illustrated as in FIG. 11 , includes a Mobility Management Entity (MME), a User Plane Entity (UPE), and an Inter Access System Anchor (IASA). The MME performs mobility management in the control plane, including user context and mobility status management, user temporary identity identifier assignment and so forth, corresponding to the control plane of an SGSN inside GPRS/UMTS; the UPE is used to initiate paging for downlink data in idle state, manages and stores IP bearer parameters and routing information inside the network and so forth, corresponding to the data plane of an SGSN and a GGSN in GPRS/UMTS; the IASA is an anchor in the user plane between different systems. A Policy and Charging Rule Function (PCRF) entity is used for policy control decision and charging control of data flow. A Home Subscriber Server (HSS) is used to store user subscription information. For the SAE system, if the MME and the UPE are separate, and the UPE and the 3GPP Anchor are in a same entity, the systematic architecture is similar to the architecture in the direct-tunnel mechanism where the MME corresponds to an SGSN, and the UPE/3GPP Anchor (referred to as UPE hereinafter) corresponds to a GGSN. Therefore the data forwarding processing method stated above can be used for data forwarding when a handover or change between a GERAN/UTRAN system and an SAE system takes place. When a handover or change from a GERAN system to an SAE system takes place, the MME and the UPE (user plane anchor of the GERAN/UTRAN and the SAE) exchange messages including a forward data request message and a forward data response message, to obtain a data forwarding tunnel identifier of the UPE, and inform the 2G SGSN of the data forwarding tunnel identifier of the UPE. The 2G SGSN forwards a data packet to the UPE; the UPE buffers the forwarded data packet and forwards the buffered forwarded data packet to the evolved access network on completion of update of user plane routing. When a handover or change from an SAE system to a GERAN system takes place, the MME and the UPE exchange messages including a forward data request message and a forward data response message, to obtain a data forwarding tunnel identifier of the UPE, and inform the evolved access network of the data forwarding tunnel identifier of the UPE. The evolved access network forwards a data packet to the UPE; the UPE buffers the forwarded data packet and forwards the buffered forwarded data packet to the 2G SGSN on completion of update of user plane routing. When a handover or change from a UTRAN system to an SAE system takes place, the 3G SGSN and the UPE exchange messages including a forward data request message and a forward data response message, to obtain a data forwarding tunnel identifier of the UPE, and inform the source RNC of the data forwarding tunnel identifier of the UPE. The source RNC forwards a data packet to the UPE; the UPE buffers the forwarded data packet and forwards the buffered forwarded data packet to the evolved access network on completion of update of user plane routing. When a handover or change from an SAE system to a UTRAN system takes place, the MME and the UPE exchange messages including a forward data request message and a forward data response message, to obtain a data forwarding tunnel identifier of the UPE, and inform the evolved access network of the data forwarding tunnel identifier of the UPE. The evolved access network forwards a data packet to the UPE; the UPE buffers the forwarded data packet and forwards the buffered forwarded data packet to the target RNC on completion of update of user plane routing. Now refer to FIGS. 12 to 15 . Another data processing method embodiment provided by the present invention is described. With reference to FIG. 12 , a data processing method when a handover from a GERAN to a UTRAN takes place includes: step 1201 : a source BSS decides to initiate a handover; step 1202 : the source BSS sends a handover request message to an old SGSN, i.e. 2G SGSN; step 1203 : the 2G SGSN sends a forward relocation request message to a new SGSN, i.e. 3G SGSN; step 1204 : the 3G SGSN builds a relocation request message and sends the message to a target RNC; step 1205 : the target RNC sends relocation request acknowledge message to the 3G SGSN; step 1206 : the 3G SGSN sends a forward data request message to a GGSN, to request the GGSN to assign a data forwarding tunnel for data forwarding, an identifier of a GTP tunnel of the target RNC side is carried in the message, subsequently the GGSN will forward data of a lossless service to the GTP tunnel; step 1207 : the GGSN returns a forward data response message to the 3G SGSN, assigns a data forwarding tunnel identifier to the data forwarding tunnel, and sends to the 3G SGSN in the response message; step 1208 : the 3G SGSN sends a forward relocation response message to the 2G SGSN, a data forwarding tunnel identifier carried in the message is the data forwarding tunnel identifier of the GGSN; step 1209 : the 2G SGSN receives a data packet from the GGSN, and sends the data packet to an MS via the source BSS; step 1210 : for data of a lossless service, the 2G SGSN forwards the data packet to the GGSN according to the data forwarding tunnel identifier carried in the forward relocation response message sent by the 3G SGSN, the GGSN forwards the data packet forwarded by the 2G SGSN to the target RNC on receipt of the data packet; step 1211 : the 2G SGSN sends a handover request acknowledge message to the source BSS; step S 1212 : the MS sends a handover to UTRAN complete message to the target RNC; step S 1213 : the target RNC sends a relocation complete message to the 3G SGSN; step S 1214 : the 3G SGSN sends an update context request message to the GGSN; step S 1215 : the GGSN returns an update context response message to the 3G SGSN. With reference to FIG. 13 , a data processing method when a handover from a UTRAN to a GERAN takes place includes: step S 1301 : a source RNC decides to initiate a handover; step S 1302 : the source RNC sends a relocation request message to an old SGSN, i.e. 3G SGSN; step S 1303 : the 3G SGSN sends a forward relocation request message to a new SGSN, i.e. 2G SGSN; step S 1304 : the 2G SGSN builds a handover request message, and sends the message to a target BSS; step S 1305 : the target BSS sends a handover request acknowledged message to the 2G SGSN; step S 1306 : the 2G SGSN sends a forward relocation response message to the 3G SGSN; step S 1307 : the 3G SGSN sends a forward data request to a GGSN, to request the GGSN to assign a data forwarding tunnel for data forwarding, an identifier of a data forwarding tunnel of the 2G SGSN is carried in the message, subsequently the GGSN will forward data of a lossless service to the data forwarding tunnel; step S 1308 : the GGSN returns a forward data response message to the 3G SGSN, assigns a data forwarding tunnel identifier to the data forwarding tunnel and carries the data forwarding tunnel identifier in the response message to the 3G SGSN; step S 1309 : the 3G SGSN receives a data packet from the GGSN, and sends the data packet to an MS via the source RNC; step S 1310 : the 3G SGSN sends a relocation command message to the source RNC, a data forwarding tunnel identifier carried in the message is the data forwarding tunnel identifier of the GGSN; step S 1311 : for data of a lossless service, the source RNC forwards the data packet to the GGSN according to the data forwarding tunnel identifier carried in the relocation command message sent by the 3G SGSN, the GGSN forwards the data packet forwarded by the source RNC to the 2G SGSN on receipt of the data packet, the 2G SGSN forwards the data packet to the target BSS; step S 1312 : the target BSS sends a handover complete message to the 2G SGSN; step S 1313 : the 2G SGSN sends an update context request message to the GGSN; step S 1314 : the GGSN returns an update context response message to the 2G SGSN. With reference to FIG. 14 , a data processing method when a change from a GERAN to a UTRAN takes place includes. step S 1401 : an MS decides to initiate an intersystem change; step S 1402 : the MS sends a routing area update request message to a new SGSN, i.e. 3G SGSN; step S 1403 : the 3G SGSN sends an SGSN context request message to an old SGSN, i.e. 2G SGSN, to obtain user context; step S 1404 : the 2G SGSN returns SGSN context response message to the 3G SGSN, and carries the user context information in the message; step 1405 : RAB assignment procedure is performed between the 3G SGSN and an RNC, thereby establishing RAB; step S 1406 : the 3G SGSN sends an update PDP context request message to a GGSN, to request to change user plane routing from the GGSN to the 3G SGSN; step S 1407 : the GGSN returns an update PDP context response to the 3G SGSN; step S 1408 : the 3G SGSN sends a forward data request message to the GGSN, to request the GGSN to assign a data forwarding tunnel for data forwarding, an identifier of a GTP tunnel of the target RNC side is carried in the message, subsequently the GGSN will forward data of a lossless service to the GTP tunnel; step S 1409 : the GGSN returns a forward data response message to the 3G SGSN, assigns a data forwarding tunnel identifier to the data forwarding tunnel, and carries the data forwarding tunnel identifier in the response message to the 3G SGSN; step S 1410 : the 3G SGSN sends an SGSN context acknowledge message to the 2G SGSN, informing the 2G SGSN that the 3G SGSN is ready to receive data packets, a data forwarding tunnel identifier carried in the message is the data forwarding tunnel identifier of the GGSN; step S 1411 : the 2G SGSN duplicates a buffered data packet and forwards to the GGSN according to the data forwarding tunnel identifier carried in the SGSN context acknowledge message sent by the 3G SGSN, the GGSN forwards the data packet forwarded by the 2G SGSN to the target RNC on receipt of the data packet; step S 1412 : the 3G SGSN returns a routing area update accept message to the MS; step S 1413 : the MS returns a routing area update complete message to the 3G SGSN; step S 1414 : the 3G SGSN sends an update context request message to the GGSN, to change a downlink GTP tunnel identifier of user context in the GGSN to the GTP tunnel identifier of the RNC; step S 1415 : the GGSN returns an update context response message to the 3G SGSN. With reference to FIG. 15 , a data processing method when a change from a UTRAN to a GERAN takes place includes: step S 1501 : an MS decides to initiate an intersystem change; step S 1502 : the MS sends a routing area update request message to a new SGSN, i.e. 2G SGSN; step S 1503 : the 2G SGSN sends an SGSN context request message to an old SGSN, i.e. 3G SGSN, to obtain user context; step S 1504 : the 3G SGSN sends an SRNS context request message to a source RNC; step S 1505 : the source RNC returns an SRNS context response message to the 3G SGSN, stops sending downlink data to the MS, and buffers the data; step S 1506 : the 3G SGSN returns an SGSN context response message to the 2G SGSN, and carries the user context information in the message; step S 1507 : the 2G SGSN sends an SGSN context acknowledge message to the 3G SGSN, informing the 3G SGSN that the 2G SGSN is ready to receive data packets; step S 1508 : the 3G SGSN sends a forward data request to a GGSN, to request the GGSN to assign a data forwarding tunnel for data forwarding, an identifier of a data forwarding tunnel of the 2G SGSN is carried in the message, subsequently the GGSN will forward data of a lossless service to the data forwarding channel; step S 1509 : the GGSN returns a forward data response message to the 3G SGSN, assigns a data forwarding tunnel identifier to the data forwarding tunnel, and carries the data forwarding tunnel identifier in the response message to the 3G SGSN; step S 1510 : the 3G SGSN sends an SRNS data forward command to the source RNC, a data forwarding tunnel identifier carried in the message is the data forwarding tunnel identifier of the GGSN, the source RNC duplicates a buffered data packet and forwards to the GGSN, the GGSN forwards the data packet forwarded by the source RNC to the 2G SGSN on receipt of the data packet; step S 1511 : the 2G SGSN sends an update PDP context request message to the GGSN; step S 1512 : the GGSN returns an update PDP context response message to the 2G SGSN; step S 1513 : the 2G SGSN returns a routing area update accept message to the MS; step S 1514 : the MS returns a routing area update complete message to the 2G SGSN. The data forwarding processing method stated above can be used for data forwarding when a handover or change between a GERAN/UTRAN system and an SAE system takes place. When a handover or change from a GERAN system to an SAE system takes place, the MME and the UPE exchange messages including a forward data request message and a forward data response message, to obtain a data forwarding tunnel identifier of the UPE. Meanwhile the MME informs the UPE of a tunnel identifier of the access network side, and informs the 2G SGSN of the data forwarding tunnel identifier of the UPE. The 2G SGSN forwards a data packet to the UPE, and the UPE further forwards the data packet to the evolved access network. When a handover or change from an SAE system to a GERAN system takes place, the MME and the UPE exchange messages including a forward data request message and a forward data response message, to obtain a data forwarding tunnel identifier of the UPE. Meanwhile, the MME informs the UPE of a tunnel identifier of the 2G SGSN, and then informs the evolved access network of the data forwarding tunnel identifier of the UPE. The evolved access network forwards a data packet to the UPE, and the UPE further forwards the data packet the 2G SGSN. When a handover or change from a UTRAN system to an SAE system takes place, the 3G SGSN and the UPE exchange messages including a forward data request message and a forward data response message, to obtain a data forwarding tunnel identifier of the UPE Meanwhile, the UPE is informed of a tunnel identifier of the evolved access network side. Then the 3G SGSN informs the source RNC of the data forwarding tunnel identifier of the UPE. The source RNC forwards a data packet to the UPE, and the UPE further forwards the data packet to the evolved access network. When a handover or change from an SAE system to a UTRAN system takes place, the MME and the UPE exchange messages including a forward data request message and a forward data response message, to obtain a data forwarding tunnel identifier of the UPE. Meanwhile the MME informs the UPE of a tunnel identifier of the target RNC and then informs the evolved access network of the data forwarding tunnel identifier of the UPE. The evolved access network forwards a data packet to the UPE, and the UPE further forwards the data packet to the target RNC. Another data processing method when an intersystem handover or change takes place is provided with an embodiment of the present invention, including: A user plane anchor network element sends data to a source data forwarding network element and a target side processing network element on receipt of an instruction. The instruction may be a bicast command instruction instructing the user plane anchor network element to send data to the source data forwarding network element and the target side processing network element. On completion of update of user plane routing, the user plane anchor network element stops bicasting and sends data to the target side processing network element only. With reference to FIG. 16 , a data processing method when a handover from a GERAN to a UTRAN takes place includes: step 1601 : a source BSS decides to initiate a handover; step 1602 : the source BSS sends a handover request message to an old SGSN, i.e. 2G SGSN; step 1603 : the 2G SGSN sends a forward relocation request message to a new SGSN, i.e. 3G SGSN; step 1604 : the 3G SGSN builds a relocation request message and sends the message to a target RNC; step 1605 : the target RNC sends relocation request acknowledge message to the 3G SGSN; step 1606 : the 3G SGSN sends a forward relocation response message to the 2G SGSN, an indication is carried in the message to instruct the 2G SGSN not to perform data forwarding; step 1607 : the 3G SGSN sends a bicast command message to a GGSN, instructing the GGSN to send data to the 2G SGSN and the target RNC, a GTP tunnel identifier of the target RNC is carried in the message; step 1608 : the GGSN sends a downlink data packet to the 2G SGSN and the target RNC; step 1609 : the 2G SGSN sends a handover request acknowledge message to the source BSS; step 1610 : an MS sends a handover to UTRAN complete message to the target RNC; step 1611 : the target RNC sends a relocation complete message to the 3G SGSN; step 1612 : a process of PDP context update is performed between the 3G SGSN and the GGSN, which changes a downlink GTP tunnel identifier of user in the GGSN to the GTP tunnel identifier of the target RNC, the GGSN stops data bicasting in the process; step 1613 : the GGSN sends a downlink data packet to the target RNC. With reference to FIG. 17 , a data processing method when a handover from a UTRAN to a GERAN takes place includes: step S 1701 : a source RNC decides to initiate a handover; step S 1702 : the source RNC sends a relocation request message to an old SGSN, i.e. 3G SGSN; step S 1703 : the 3G SGSN sends a forward relocation request message to a new SGSN, i.e. 2G SGSN; step S 1704 : the 2G SGSN builds a handover request message, and sends the message to a target BSS; step S 1705 : the target BSS sends a handover request acknowledged message to the 2G SGSN; step S 1706 : the 2G SGSN sends a forward relocation response message to the 3G SGSN; step S 1707 : the 3G SGSN sends a bicast command message to a GGSN, instructing the GGSN to send data to the source RNC and the 2G SGSN, a GTP tunnel identifier of the 2G SGSN is carried in the message; step S 1708 : the GGSN sends a downlink data pack to the source RNC and the 2G SGSN; step S 1709 : the 3G SGSN sends a relocation command message to the source RNC, an indication is carried in the message to instruct the source RNC not to perform data forwarding; step S 1710 : the target BSS sends a handover complete message to the 2G SGSN; step S 1711 : a process of PDP context update is performed between the 2G SGSN and the GGSN, which changes a downlink GTP tunnel identifier of user in the GGSN to the GTP tunnel identifier of the 2G SGSN, the GGSN stops data bicasting in the process; step S 1712 : the GGSN sends a downlink data packet to the 2G SGSN, the 2G SGSN sends the downlink data packet to the target BSS. With reference to FIG. 18 , a data processing method when a change from a GERAN to a UTRAN takes place includes. step S 1801 : an MS decides to initiate an intersystem change; step S 1802 : the MS sends a routing area update request message to a new SGSN, i.e. 3G SGSN; step S 1803 : the 3G SGSN sends an SGSN context request message to an old SGSN, i.e. 2G SGSN, to obtain user context; step S 1804 : the 2G SGSN returns an SGSN context response message to the 3G SGSN, and carries the user context information in the message; step 1805 : RAB assignment procedure is performed between the 3G SGSN and an RNC, thereby establishing RAB; step S 1806 : the 3G SGSN sends an SGSN context acknowledge message to the 2G SGSN, an indication is carried in the message to instruct the 2G SGSN not to perform data forwarding; step S 1807 : the 3G SGSN sends a bicast command message to the GGSN, instructing the GGSN to send data to the 2G SGSN and a target RNC, a GTP tunnel identifier of the target RNC is carried in the message; step S 1808 : the GGSN sends a downlink data packet to the 2G SGSN and the target RNC; step S 1809 : the 3G SGSN returns a routing area update accept message to the MS; step S 1810 : the MS returns a routing area update complete message to the 3G SGSN; step S 1811 : a process of PDP context update is performed between the 3G SGSN and the GGSN, which changes a downlink GTP tunnel identifier of user in the GGSN to the GTP tunnel identifier of the target RNC, the GGSN stops data bicasting in the process; step S 1812 : the GGSN sends a downlink data packet to the target RNC. With reference to FIG. 19 , a data processing method when a change from a UTRAN to a GERAN takes place includes: step S 1901 : an MS decides to initiate an intersystem change; step S 1902 : the MS sends a routing area update request message to a new SGSN, i.e. 2G SGSN; step S 1903 : the 2G SGSN sends an SGSN context request message to an old SGSN, i.e. 3G SGSN, to obtain user context; step S 1904 : the 3G SGSN sends an SRNS context request message to a source RNC; step S 1905 : the source RNC returns an SRNS context response message to the 3G SGSN, stops sending downlink data to the MS, and buffers the data; step S 1906 : the 3G SGSN returns an SGSN context response message to the 2G SGSN, and carries the user context information in the message; step S 1907 : the 2G SGSN sends an SGSN context acknowledge message to the 3G SGSN, informing the 3G SGSN that the 2G SGSN is ready to receive data packets; step S 1908 : the 3G SGSN sends a bicast command message to the GGSN, instructing the GGSN to send data to the source RNC and the 2G SGSN, a GTP tunnel identifier of the 2G SGSN is carried in the message; step S 1909 : the GGSN sends a downlink data packet to the source RNC and the 2G SGSN; step S 1910 : a process of PDP context update is performed between the 2G SGSN and the GGSN, which changes a downlink GTP tunnel identifier of user in the GGSN to the GTP tunnel identifier of the 2G SGSN, the GGSN stops data bicasting in the process; step S 1911 : the GGSN sends a downlink data packet to the 2G SGSN, the 2GSN sends the downlink data packet to the MS; step S 1912 : the 2G SGSN returns a routing area update accept message to the MS; step S 1913 : the MS returns a routing area update complete message to the 2G SGSN. The data forwarding processing method stated above can be used for data forwarding when a handover or change between a GERAN/UTRAN system and an SAE system takes place. When a handover or change from a GERAN system to an SAE system takes place, the MME sends a bicast command message to the UPE, instructing the UPE to send data to the 2G SGSN and the LTE. The UPE sends a downlink data packet to the 2G SGSN and the LTE. On completion of update of user plane routing, the UPE stops downlink data packet bicasting, and sends a downlink data packet to the LTE only. When a handover or change from an SAE system to a GERAN system takes place, the MME sends a bicast command message to the UPE, instructing the UPE to send data to the LTE and the 2G SGSN. The UPE sends a downlink data packet to the LTE and the 2G SGSN. On completion of update of user plane routing, the UPE stops downlink data packet bicasting, and sends a downlink data packet to the 2G SGSN only. When a handover or change from a UTRAN system to an SAE system takes place, the MME sends a bicast command message to the UPE, instructing the UPE to send data to the source RNC and the LTE. The UPE sends a downlink data packet to the source RNC and the LTE. On completion of update of user plane routing, the UPE stops downlink data packet bicasting, and sends a downlink data packet to the LTE only. When a handover or change from an SAE system to a UTRAN system takes place, the MME sends a bicast command message to the UPE, instructing the UPE to send data to the LTE and the target RNC. The UPE sends a downlink data packet to the LTE and the target RNC. On completion of update of user plane routing, the UPE stops downlink data packet bicasting, and sends a downlink data packet to the target RNC only. With reference to FIG. 20 , a data processing system is provided in an embodiment of the present invention, including a source data forwarding network element, a target side processing network element and a user plane anchor network element, wherein the user plane anchor network element is provided with a receipt unit adapted to receive data forwarded by the source data forwarding network element, and a sending unit adapted to forward the received data to the target side processing network element. In an embodiment of the present invention, the source data forwarding network element is a 2G Serving GPRS Support Node (SGSN), the user plane anchor network element is a Gateway GPRS Support Node (GGSN), and the target side processing network element is a target Radio Network Controller (RNC). In another embodiment of the present invention, the source data forwarding network element is a source RNC, the user plane anchor network element is a GGSN, and the target side processing network element is a 2G SGSN. The data processing system further includes: a tunnel identifier acquisition unit, arranged in the 3G SGSN and adapted to acquire a data forwarding tunnel identifier of the GGSN; and a tunnel identifier sending unit, adapted to send a GTP tunnel identifier of the target RNC side to the GGSN. The data processing system further includes: a data packet buffer unit, arranged in the GGSN and adapted to receive a data packet forwarded by the 2G SGSN and buffer a data packet forwarded by the target side processing network element; and a data packet sending unit, adapted to send the buffered data packet. In the direct-tunnel mechanism, when a handover or change between a GERAN and a UTRAN takes place, data forwarded by the source data forwarding network element can be buffered in the data packet buffer unit, which forwards the buffered data packet to the target RNC when the GGSN completes update of user plane routing or the GGSN receives an update PDP context request message sent by the 3G SGSN. Also, the data forwarded by the source data forwarding network element can be forwarded directly to the target side processing network element. When an intersystem handover or change takes place, interactions among the source data forwarding network element, target side processing network element and the user plane anchor network element are same or similar to the steps described in the above embodiments. When the user plane anchor network element receive an instructive message and sends data to the source data forwarding network element and/or the target side processing network element, the user plane anchor network element updates user plane routing and only sends the data to the target side processing network element as instructed in the message according to the updated user plane routing. Those skilled in the art should understand that each step in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in computer readable storage medium such as ROM/RAM, magnetic disk and optical discs. Alternatively, the embodiments can be implemented with respective integrated circuit modules, or the steps of which can be made into separate integrated circuit modules. Therefore, the present invention is not limited to any particular hardware or software combination. As can be seen from the above embodiments, with the data processing methods in the direct-tunnel mechanism when a handover or change between a GERAN and a UTRAN takes place, a GGSN can buffer data forwarded by a source data forwarding network element and then send the data to a target side processing network element, alternatively, the GGSN can send the data forwarded by the source data forwarding network element directly to the target side processing network element. The problem that the data processing method in the conventional art is not applicable in the direct-tunnel mechanism is solved. Handover or change between a GERAN and a UTRAN in the direct-tunnel mechanism does not affect forwarding of service data. Exemplary embodiments of the present invention are described. It should be noted that those skilled in the art may make various alternations or modifications without departing from the principle of the present invention. The alternations and modifications should be covered within the scope of the present invention.

A data processing method when the handover or change appears between systems includes: the source data forwarding network element forwards the data to the user plane anchor network element; the user plane anchor network element forwards the data to the target side processing network element. A data processing method when the handover or change appears between systems is also provided by the present invention, which includes: the user plane anchor network element receives the message indication, transmits the data to at least one of the source data forwarding network element and the target side processing network element; the user plane anchor network element updates the route of the user plane, and transmits the data to the target side processing network element according to the updated route of the user plane. A data processing method when handover or change appears between GERAN/UTRAN systems under the Direct Tunnel solution is provided by the present invention, which can be applied to the Direct Tunnel solution.

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 61/770,620, filed on Feb. 28, 2013 which is incorporated herein by reference in its entirety. FIELD OF THE ART [0002] The present disclosure generally relates to gel compositions and wellbore treatment fluids for use in hydraulic fracturing applications. BACKGROUND [0003] In the drilling, completion, and stimulation of oil and gas wells, well treatment fluids are often pumped into well bore holes under high pressure and at high flow rates causing the rock formation surrounding the well bore to fracture. A type of well treatment commonly utilized for stimulating hydrocarbon production from a subterranean zone penetrated by a well bore is hydraulic fracturing. Hydraulic fracturing, also referred to as fracing (or fracking), is used to initiate production in low-permeability reservoirs and re-stimulate production in older producing wells. In hydraulic fracing, a fluid composition is injected into the well at pressures effective to cause fractures in the surrounding rock formation. Fracing is used both to open up fractures already present in the formation and create new fractures. Proppants, such as sand and ceramics, are used to keep induced fractures open both during and after fracturing treatment. To place the proppants inside the fracture, the proppant particles are suspended in a fluid that is pumped into the subterranean formation. Generally, this fluid has a viscosity sufficient to maintain suspension of the particles. [0004] For ideal performance, a hydraulic fracturing fluid should be sufficiently viscous to create a fracture of adequate width and be able to transport large quantities of proppants into the fracture. The viscosity of the fluid can be enhanced or modified by addition of synthetic and/or natural polymers, or other rheology modifiers. Examples of polymer-enhanced fluids used to increase the viscosity of hydraulic fracturing fluids include slickwater systems, linear gel systems, and crosslinked gel systems. Of these, crosslinked gel systems are the most viscous. [0005] In a crosslinked gel system, a linear polymer or gel, for example, a fluid based on guar or modified guar, is crosslinked with added reagents such as borate, zirconate, and titanate in the presence of alkali. The most common version of crosslinked gel is known in the art as guar-borate gel. The crosslinked gel fluid increases the viscosity of the fracturing fluid, such that proppants can be effectively suspended. [0006] Once the hydraulic fracturing fluid has delivered proppant to the fracture or delivered sand in gravel packing or frac packing operations, it is often desirable to lower the viscosity of the fracturing fluid such that the fluid can be recovered from the formation using minimal energy. The removal of the spent fracturing fluids from the subterranean formation is typically required to allow hydrocarbon production. This reduction in viscosity of the fracturing fluid is often achieved using a breaker, i.e., a compound that breaks the cross-linking bonds within the gel. [0007] Synthetic polymers, for example polyacrylamide (PAM) polymers, can form permanent gels under acidic conditions with metal crosslinking agents, such as aluminum-, chromium-, zirconium- and titianium-based complexes. Such gels can be used, for example, to control conformance in enhanced oil recovery (EOR) applications, where subsequent breaking to significantly reduce viscosity is not necessary. However, for fracing fluid applications, the acidity of the formation in hydraulic fracturing is usually not high, and breaking of the crosslinked gel improves fluid recovery. SUMMARY [0008] Disclosed herein are gel compositions comprising an acrylamide polymer or copolymer having a charge between about 5% to about 35%, or more specifically about 15% to about 20%, and dialdehyde. The gel composition is formed by combining the acrylamide polymer or copolymer and dialdehyde in an aqueous solution at a pH in the range of about 7.5 to about 11, wherein the molar ratio of dialdehyde to monomers of the acrylamide polymer or copolymer is in the range of about greater than about 0.2 to about 2.0. [0009] Methods to produce the gel composition, methods of treating a wellbore comprising injecting the gel composition into a wellbore, and well treatment fluids comprising the gel composition are also disclosed herein. [0010] Further, methods of treating a wellbore comprising injecting a composition comprising an acrylamide polymer or copolymer having a charge between 15% to 20% into a wellbore; injecting a composition comprising dialdehyde into the wellbore, and injecting a pH modifying agent into the wellbore in an amount sufficient to produce a downhole solution pH in the range of about 7.5 to about 11, to produce an in-situ gel composition comprising an acrylamide polymer or copolymer crosslinked with dialdehyde. [0011] Wellbore treatment fluids comprising an acrylamide polymer or copolymer and dialdehyde are also disclosed herein. The wellbore treatment fluid may be formed (in whole or in part) prior to injection into the wellbore or in situ, where the acrylamide polymer/copolymer and the crosslinker are added to the wellbore separately. The wellbore treatment fluid may optionally comprise one or more additional components, such as proppants and pH control agents. [0012] The disclosure may be understood more readily by reference to the following detailed description of the various features of the disclosure and the examples included therein. BRIEF DESCRIPTION OF FIGURES [0013] FIG. 1 provides a graph showing the results of the viscosity analyses for exemplary gels according to the embodiments and a guar gel. [0014] FIG. 2 provides a graph showing the relationship between charge and viscosity for anionic copolymers at various charges. DETAILED DESCRIPTION [0015] The present disclosure provides cross-linked gel compositions which comprise an acrylamide polymer or copolymer and dialdehyde. The gel compositions are useful for increasing the viscosity of hydraulic fracturing fluids. In particular, the gel compositions have a charge (mole percent) within a specific range that is especially useful for viscosifying wellbore treatment fluids, enhancing delivery of proppants into fractures. The exemplary gel compositions may break under certain conditions, which can increase fluid recovery in hydraulic fracturing applications. The exemplary gel compositions can be used as a synthetic replacement for crosslinked guar compositions in hydraulic fracturing applications, with comparable performance. Like guar gels, the exemplary gel compositions provide high viscosity with a relatively low amount of active polymer in the composition. Exemplary gel compositions may be easier to manufacture, and of a more reliable quality, than guar gels. [0016] Gel Compositions [0017] In one aspect, the present invention is a gel composition comprising an acrylamide polymer or copolymer crosslinked with dialdehyde. [0018] As used herein, the term “acrylamide polymer” refers to a homopolymer of acrylamide and encompasses acrylamide polymers chemically modified (e.g., hydrolyzed) following polymerization. [0019] As used herein the term “acrylamide copolymer” refers to a polymer comprising an acrylamide monomer and one or more comonomers. The comonomer may be anionic, cationic or non-ionic. In certain embodiments, the comonomer is hydrophobic. The acrylamide copolymer may be unmodified or chemically modified. Representative, non-limiting co-monomers include acrylic acid, vinyl acetate, vinyl alcohol and/or other unsaturated vinyl monomers. [0020] In one embodiment, the acrylamide copolymer comprises an anionic comonomer. In some embodiments, the anionic monomer is selected from the group consisting of (meth)acrylic acid, alkali/alkaline/ammonium salts of (meth)acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, alkali/alkaline/ammonium salts of 2-acrylamido-2-methylpropanesulfonic acid, maleic acid, alkali/alkaline/ammonium salts of maleic acid and the like. [0021] In another embodiment, the acrylamide copolymer comprises a cationic comonomer. In some embodiments, the cationic monomer is selected from the group consisting of (meth)acrylamidoethyltrimethylammonium chloride, (meth) acrylamido propyltrimethylammonium chloride and the like. [0022] In another embodiment, the acrylamide copolymer comprises a non-ionic comonomer. In some embodiments, the non-ionic monomer is selected from the group consisting (meth)acrylamide, maleic anhydride. [0023] In an exemplary embodiment, the acrylamide copolymer comprises an acrylamide monomer and an anionic comonomer, but does not include a cationic comonomer. [0024] In one embodiment, the acrylamide polymer or copolymer is characterized by a charge of about 0% to about 40%, about 5% to about 35%, about 15% to about 30%, about 15% to about 20% or about 20% to about 30%. In one embodiment, the charge is in the range of about 5% to about 35% and provides a particularly high viscosity that provides substantial suspending power. In another embodiment, the charge is in the range of about 15% to about 20% and provides a particularly high viscosity that provides substantial suspending power. [0025] In another embodiment, the acrylamide polymer or copolymer is characterized by a charge of about 10%, about 15%, about 20%, about 25%, about 30%, about 35% or about 40%. [0026] The range of charge for the gel composition disclosed herein is a function of the charge of the polyacrylamide copolymer comprising charged monomers or the chemically modified polyacrylamide polymer or copolymer. [0027] In a particular embodiment, the acrylamide copolymer comprises from about 30 to about 90, about 40 to about 80, about 50 to about 70 or about 60 mole % acrylamide. [0028] In a particular embodiment, the weight ratio of the acrylamide monomer to the one or more comonomers is about 10:90 to 90:10. [0029] In a particular embodiment, the acrylamide polymer or copolymer is characterized by a degree of hydrolysis of about 5 to about 10%, about 10 to about 15%, about 15 to about 20%, about 20 to about 25%, about 25 to about 30% or greater than about 30%. In a more particular embodiment, the acrylamide polymer or copolymer is characterized by a degree of hydrolysis of about 15, about 16, about 17, about 18, about 19 or about 20%. [0030] In one embodiment, acrylamide polymers or copolymers are water dispersible. [0031] In one embodiment, the acrylamide polymer or copolymer has a weight average molecular weight of greater than or equal to about 0.5 million g/mol. In another embodiment, the acrylamide polymer or copolymer has a weight average molecular weight of in the range of about 0.5 million g/mol to about 30 million g/mol. [0032] The liquid used to form the gel composition any suitable aqueous liquid that does not adversely react with the acrylamide polymer or copolymer, such as fresh water, salt water, brine, or any other aqueous liquid. [0033] The dialdehyde used to cross-link the acrylamide polymer or copolymer may be any suitable dialdehyde. Representative, non-limiting examples of dialdehydes include glyoxal, malondialdehyde, succindialdehyde, glutaraldehyde, adipaldehyde, o-phthaldehyde, m-phthaldehyde, p-phthaldehyde, and combinations and mixtures thereof. [0034] In one embodiment, the dialdehyde is a glyoxal. [0035] In one embodiment, the gel composition comprises an acrylamide polymer, crosslinked with glyoxal. In a particular embodiment, the gel composition comprises an acrylamide polymer crosslinked with glyoxal, wherein the acrylamide polymer is characterized by a charge in range of about 5% to about 40% and provides a particularly high viscosity that provides substantial suspending power. In one embodiment, the charge is in the range of about 15% to about 20% and provides a particularly high viscosity that provides substantial suspending power. In a particular embodiment, the charge is about 10%, about 15%, about 20%, about 25%, about 30%, about 35% or about 40%. [0036] In another embodiment, the gel composition comprises an acrylamide copolymer crosslinked with glyoxal. In a particular embodiment, the gel composition comprises an acrylamide copolymer crosslinked with glyoxal, wherein the acrylamide copolymer is characterized by a charge in range of about 5% to about 40% and provides a particularly high viscosity that provides substantial suspending power. In one embodiment, the charge is in the range of about 15% to about 20% and provides a particularly high viscosity that provides substantial suspending power. In a particular embodiment, the charge is about 10%, about 15%, about 20%, about 25%, about 30%, about 35% or about 40%. [0037] The amount of the acrylamide polymer or copolymer in the gel composition may depend, for example, on the particular polymer/copolymer used, the purity of the polymer/copolymer, and properties desired in the final composition. In one embodiment, the gel composition comprises from about 0.05 to about 5% by weight polymer or copolymer, from about 0.1 to about 1% or from about 0.2 to about 5% by weight polymer or copolymer, based on the total weight of the composition. In another embodiment, the gel composition comprises about 5, about 0.1 to about 3, about 0.2 to about 2, or about 0.3 to about 1% by weight percent polymer or copolymer based on the total weight of the composition. [0038] In exemplary embodiments, the gel composition comprises from about 0.1% to about 25% of acrylamide polymer or copolymer, by weight of the composition. In certain embodiments, the gel composition comprises from about 0.01% to about 25% acrylamide polymer or copolymer, by weight of the composition. [0039] In one embodiment, the gel composition comprises an acrylamide polymer or copolymer crosslinked with glyoxal wherein the polymer or copolymer (i) comprises about 0.05 to about 5% by weight polymer/copolymer and (ii) is characterized by a charge in range of about 5% to about 40%, and more particularly about 15 to about 20%. [0040] In one embodiment, the gel composition has a dialdehyde to monomer ratio of from about 0.2 to about 2.0. In exemplary embodiments, the molar ratio of dialdehyde to monomers of the acrylamide polymer or copolymer is greater than about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, about 1.0, about 1.1, about 1.2, about 1.3, about 1.4, about 1.5, about 1.6, about 1.7, about 1.8, about 1.9, about 2.0. In exemplary embodiments, the molar ratio of dialdehyde to monomers of the acrylamide polymer or copolymer is in the range of about greater than about 0.2 to about 2.0, about 0.5 to about 2.0, about 0.7 to about 2.0, about 0.8 to about 2.0, about 1.0 to about 2.0, about 1.1 to about 2.0, or about 1.0 to about 1.5. In a particular embodiment, the molar ratio of dialdehyde to monomers of the acrylamide polymer or copolymer is greater than about 1.0. [0041] In one embodiment, the gel composition comprises an acrylamide polymer or copolymer crosslinked with glyoxal wherein (i) the polymer or copolymer comprises about 0.05 to about 5% by weight polymer/copolymer and is characterized by a charge in range of about 5% to about 40%, and more particularly about 15 to about 20% and (ii) the molar ratio of dialdehyde to monomers of the acrylamide polymer or copolymer is about 0.2 to about 2.0. [0042] In exemplary embodiments, the gel compositions according to the embodiments have a viscosity of greater than or equal to about 100 cP at about 100 sec-1. The viscosity of the gel may composition may be controlled by varying the concentrations of the crosslinking agent and polymer. In a particular embodiment, the gel composition has a viscosity greater than about 150, or greater than about 200, or greater than about 250 cP, or greater than about 400 cP at about 100 sec-1. [0043] In one embodiment, the gel composition comprises an acrylamide polymer or copolymer crosslinked with glyoxal, wherein (i) the polymer/copolymer comprises about 0.05 to about 5% by weight polymer/copolymer and is characterized by a charge in range of about 5% to about 40%, and more particularly about 15 to about 20% and (ii) the molar ratio of dialdehyde to monomers of the acrylamide polymer or copolymer is about 0.2 to about 2.0; and (iii) the gel composition has a viscosity of greater than or equal to about 100 cP at about 100 sec-1. Wellbore Fluid Compositions [0044] In a second aspect, the present invention is a wellbore fluid composition comprising an acrylamide polymer or copolymer crosslinked with dialdehyde. [0045] The acrylamide polymer or copolymer may be any suitable acrylamide polymer or copolymer, such as those described above. [0046] The necessary or desired amounts of the acrylamide polymer or copolymer and dialdehyde may be determined based on various factors, including, for example, assumptions about the downhole conditions. The presence of a gel down hole may be determined by other indicators other than rheological measurements. [0047] In exemplary embodiments, a wellbore fluid composition may contain from about 0.05 to about 5%, from about 0.1 to about 1%, or from about 0.2 to about 5% by weight acrylamide polymer or copolymer, based on the total weight of the composition. [0048] In exemplary embodiments, the dialdehyde to monomer ratio is from about 0.2 to about 2.0. In exemplary embodiments, the molar ratio of dialdehyde to monomers of the acrylamide polymer or copolymer is greater than about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, about 1.0, about 1.1, about 1.2, about 1.3, about 1.4, about 1.5, about 1.6, about 1.7, about 1.8, about 1.9, about 2.0. In exemplary embodiments, the molar ratio of dialdehyde to monomers of the acrylamide polymer or copolymer is in the range of about greater than about 0.2 to about 2.0, about 0.5 to about 2.0, about 0.7 to about 2.0, about 0.8 to about 2.0, about 1.0 to about 2.0, about 1.1 to about 2.0, or about 1.0 to about 1.5. In a particular embodiment, the molar ratio of dialdehyde to monomers of the acrylamide polymer or copolymer is greater than about 1.0. [0049] In exemplary embodiments, the wellbore fluid composition comprises an acrylamide polymer or copolymer crosslinked by dialdehyde and a pH modifying agent. [0050] In certain embodiment, the wellbore fluid composition is formed (in whole or in part) prior to injection into the wellbore. In other embodiments, the wellbore fluid composition is formed (in whole or in part) in situ (i.e., in the wellbore). Where the wellbore fluid composition is formed in situ, the components of the well fluid composition may be injected into the wellbore simultaneously or sequentially, in any order. [0051] In exemplary embodiments, the wellbore fluid composition is formed in situ by injecting (i) a composition comprising an acrylamide polymer or copolymer and a pH modifying agent and (ii) a composition comprising dialdehyde, where the injection of (i) and (ii) occurs simultaneously or sequentially, in any order. [0052] In exemplary embodiments, the wellbore fluid composition is formed in situ by injecting (i) a composition comprising dialdehyde and a pH modifying agent and (ii) a composition comprising an acrylamide polymer or copolymer, where the injection of (i) and (ii) occurs simultaneously or sequentially, in any order. [0053] In exemplary embodiments, the wellbore fluid composition is formed in situ by injecting (i) a composition comprising an acrylamide polymer or copolymer; (ii) a composition comprising dialdehyde may be combined; and (iii) a composition comprising a pH modifying agents, wherein the injection of (i)-(iii) occurs simultaneously or sequentially, in any order. [0054] In exemplary embodiments, the pH modifying agent is any suitable pH modifying agent and may be in the form of an aqueous solution, for example an aqueous solution comprising a base, an acid, a pH buffer, or any combination thereof. In exemplary embodiments, the pH modifying agent is a potassium carbonate and potassium hydroxide mixture or a sodium bicarbonate and sodium carbonate mixture. In exemplary embodiments, a wellbore treatment fluid comprises a gel composition as described herein. [0055] In exemplary embodiments, the wellbore treatment fluid optionally comprises a proppant, for example natural or synthetic proppants, including but not limited to glass beads, ceramic beads, sand, gravel, and bauxite and combinations thereof. Exemplary proppants may be coated or contain chemicals; more than one can be used sequentially or in mixtures of different sizes or different materials. The proppant may be resin coated (curable), or pre-cured resin coated. The proppant may be any suitable shape, including substantially spherical materials, fibrous materials, polygonal materials (such as cubic materials), and combinations thereof. In one embodiment, the proppant is a reduced density proppant. [0056] In exemplary embodiments, the wellbore treatment fluids comprising the gel compositions, or dialdehyde and acrylamide polymer or copolymer compositions for forming the gel compositions, can be used in any well treatment fluid where viscosification is desired including but not limited to stimulation and completion operations. For example, the wellbore treatment fluid can be used for hydraulic fracturing applications. In these applications, the fracturing fluid, i.e. wellbore treatment fluid, can be configured as a gelled fluid, a foamed gel fluid, acidic fluids, water and potassium chloride treatments, and the like. The fluid is injected at a pressure effective to create one or more fractures in the subterranean formation. Depending on the type of well treatment fluid utilized, various additives may also be added to the wellbore fluid to change the physical properties of the fluid or to serve a certain beneficial function. In one embodiment, a propping agent such as sand or other hard material is added which serves to keep the fractures open after the fracturing operation. Also, fluid loss agents may be added to partially seal off the more porous sections of the formation so that the fracturing occurs in the less porous strata. Other oilfield additives that may also be added to the wellbore treatment fluid include antifoams, scale inhibitors, H 2 S and or O 2 scavengers, biocides, surface tension reducers, breakers, buffers, surfactants and non-emulsifiers, fluorocarbon surfactants, clay stabilizers, fluid loss additives, foamers, friction reducers, temperature stabilizers, diverting agents, shale and clay stabilizers, paraffin/asphaltene inhibitors, corrosion inhibitors. [0057] In exemplary embodiments, the wellbore treatment fluid may optionally further comprise additional additives, including, but not limited to, acids, fluid loss control additives, gas, corrosion inhibitors, scale inhibitors, catalysts, clay control agents, biocides, friction reducers, combinations thereof and the like. For example, in some embodiments, it may be desired to foam the storable composition using a gas, such as air, nitrogen, or carbon dioxide. [0058] Method of Making the Gel Composition [0059] In a third aspect, the present invention is a method of making a gel composition comprising an acrylamide polymer or copolymer crosslinked by dialdehyde. [0060] In one embodiment, a method of making a gel composition comprises combining or contacting an acrylamide polymer or copolymer with a dialdehyde in an aqueous medium, wherein the molar ratio of dialdehyde to monomers of the acrylamide polymer or copolymer is in the range of about greater than about 0.2 to about 2.0, or from about 1 to 1.5, at a temperature and for a period of time sufficient to produce the gel composition. [0061] The pH of the aqueous medium may vary. In one embodiment, the pH of the aqueous solution is greater than about 7.5, about 8.0, about 8.5, about 9.0, about 10.0, about 10.2, about 10.5, about 10.7, or about 11. In exemplary embodiments, the pH is in the range of about 7.5 to about 11, about 8.5 to about 11, about 9.0 to about 11, about 10 to about 11, or about 10.2 to about 10.7. In a particular embodiment, the pH is greater than about 9.0. The pH modifying agents which may be used to modify the pH of the gel or the composition in which the gel is formed are any pH modifying agents suitable, for example basic compounds, which are inert relatively to the polymer and the dialdehyde, for example inorganic compounds, such as alkaline and alkaline-earth hydroxides or salts, including but not limited to alkaline carbonate or phosphate. [0062] In exemplary embodiments, acrylamide polymer or copolymer is provided in the form of a fine aqueous dispersion or emulsion of the acrylamide polymer or copolymer. In exemplary embodiments, the acrylamide polymer or copolymer component is about 0.1 to 1 wt. % of the acrylamide polymer or copolymer in the solution, dispersion or emulsion. [0063] In exemplary embodiments, the dialdehyde is in the form of a dialdehyde in an aqueous solution. In exemplary embodiments, the acrylamide polymer or copolymer component and/or the dialdehyde component are each adjusted to a pH in the range of about 7.5 to about 11 prior the step of combining or contacting the components. In exemplary embodiments, the acrylamide polymer or copolymer component is prepared by shearing, agitating or stirring the acrylamide polymer or copolymer in an aqueous medium until a fine dispersion or emulsion is obtained. In exemplary embodiments, the pH of the fine aqueous dispersion or emulsion of the acrylamide polymer or copolymer is adjusted as desired, for example, adjusted to a pH in the range of about 7.5 to about 11.0. In exemplary embodiments, the step of combining or contacting the acrylamide polymer or copolymer with dialdehyde in an aqueous solution includes shearing, agitating or stirring the components to form a thoroughly blended mixture or a gel composition. In exemplary embodiments, the final pH of the mixture or gel composition is recorded, and then the gel is tested for viscosity in a rheometer (e.g. a Grace Instrument M5600 HPHT Rheometer). [0064] In exemplary embodiments, the aqueous solution may be in the form of an aqueous liquid, an aqueous emulsion, an aqueous dispersion or an aqueous slurry. [0065] The period of time sufficient to produce the gel composition may vary. In exemplary embodiments, the formation of the gel composition or the crosslinking of the acrylamide polymer or copolymer and dialdehyde occurs in less than about 1 hour, about 40 minutes, about 30 minutes, or about 20 minutes or less than about 10 minutes, or less than about 5 minutes. [0066] The temperature to produce the gel composition may vary. In one embodiment, the gel composition is produced at a temperature of greater than or equal to about 20° C., about 30° C., about 40° C., about 50° C., about 60° C., about 70° C., about 80° C., or about 90° C. In exemplary embodiments, the gel composition is produced in a period of time of about 1 minute to about 24 hours, about 5 minutes to about 2 hours, or about 10 minutes to about 1 hour. [0067] In one embodiment, a method to produce a gel composition comprises combining or contacting an acrylamide polymer or copolymer, or a fine aqueous dispersion or emulsion of the acrylamide polymer or copolymer, with dialdehyde in an aqueous solution at a pH in the range of about 7.5 to about 11, wherein the molar ratio of dialdehyde to monomers of the acrylamide polymer or copolymer is in the range of about greater than about 0.2 to about 2.0, at a temperature and for a period of time sufficient to produce the gel composition. [0068] In certain embodiments, the method of producing the gel composition comprises combining or contacting an acrylamide polymer or copolymer with dialdehyde in an aqueous solution at a pH in the range of about 7.5 to about 11, at a temperature and for a period of time sufficient to produce a gel composition, wherein the gel composition is partially cross-linked before it is added to the wellbore and then becomes fully-crosslinked in situ. [0069] Methods of Treating Wellbores [0070] In another aspect, the present invention is a method of treating a wellbore using a gel composition. [0071] In exemplary embodiments, a method of treating a wellbore comprises injecting a gel composition described herein into a wellbore. In exemplary embodiments, the gel composition is at least partially pre-formed and subsequently injected into the wellbore. In another embodiment, the gel composition is formed in situ. [0072] In exemplary embodiments, a method of treating a wellbore comprises injecting a composition comprising an acrylamide polymer or copolymer into a wellbore; injecting a composition comprising dialdehyde into the wellbore, and injecting a pH modifying agent into the wellbore in an amount sufficient (or calculated to be sufficient) to produce a downhole solution pH in the range of about 7.5 to about 11, to produce an in-situ gel composition comprising an acrylamide polymer or copolymer crosslinked with dialdehyde. [0073] In exemplary embodiments, the wellbore treatment fluid or gel composition may be used for carrying out a variety of subterranean treatments, including, but not limited to, drilling operations, fracturing treatments, and completion operations (e.g., gravel packing) In exemplary embodiments, the wellbore treatment fluid or gel composition may be used in treating a portion of a subterranean formation. In exemplary embodiments, the wellbore treatment fluid or gel composition may be introduced into a well bore that penetrates the subterranean formation. In exemplary embodiments, the wellbore treatment fluid or gel composition may be used in fracturing treatments. [0074] The wellbore treatment fluids and gel compositions of the present embodiments may be used in any subterranean treatment as desired. Such subterranean treatments include, but are not limited to, drilling operations, stimulation treatments, and completion operations. Those of ordinary skill in the art, with the benefit of this disclosure, will be able to recognize a suitable subterranean treatment where friction reduction may be desired. [0075] In exemplary embodiments, the wellbore treatment fluid, gel compositions and methods can be used in or injected into fresh water, salt water or brines. [0076] In exemplary embodiments, wellbore treatment fluid, gel compositions and methods can be used within a temperature range of about 20° C. to about 205° C., about 50° C. to about 200° C., or about 70° C. to about 200° C. [0077] In exemplary embodiments, a method of fracturing a subterranean formation comprises: providing a wellbore treatment fluid or gel composition according to the present embodiments; and placing the wellbore treatment fluid or gel composition into a subterranean formation so as to create or enhance a fracture in the subterranean formation. [0078] In exemplary embodiments, a method of fracturing a subterranean formation comprises: providing a wellbore treatment fluid or gel composition according to the present embodiments; and pumping the wellbore treatment fluid or gel composition so as to form or extend a fracture in the subterranean formation and deposit the wellbore treatment fluid or gel composition in the fracture. [0079] In exemplary embodiments, the method further comprises allowing the gel composition in the fracture to break. In exemplary embodiments, the gel composition breaks without the addition of breaking agents or breakers. In exemplary embodiments, the method further comprises the addition of breaking agents or breakers. Representative, non-limiting examples of breakers include persulfates of ammonium, sodium and potassium, sodium perborate, hydrogen peroxide, organic peroxides, percarbonates, perphosphates, organic acids, perphosphate esters, amides, ammonium sulfate, enzymes, copper compounds, ethylene glycol, glycol ethers, and combinations thereof [0080] The following examples are presented for illustrative purposes only, and are not intended to be limiting. EXAMPLES Example 1 Preparation and Viscosity Analysis of Exemplary Glyoxal-Crosslinked-Polymer Gels [0081] Exemplary gels were prepared by the following protocol. About 0.4 wt % of active acrylamide polymer in water was stirred for about 10 minutes to about 20 minutes at room temperature. Once the solution was thoroughly blended, the pH of the solution was measured and adjusted using a pH buffer solution to about 9.8 to about 10.3. 0.33, 0.49 or 0.65 wt. % of glyoxal was added to the solution. The mixture was stirred until the glyoxal was well incorporated. The viscosity of each of the resulting gels was measured on a Grace Instrument M5600 HPHT Rheometer at 180° F. [0082] The Grace Instrument M5600 HPHT Rheometer which is a true Couette, coaxial cylinder, rotational, high pressure and temperature rheometer. The instrument is fully automated and all data acquisition is under computer control. The temperature of the sample is maintained with an oil bath which runs from ambient to 500° F. The gel is also subjected to pressure with nitrogen gas to prevent boiling off the solvent. After 20 minutes of shear conditioning, the gel is subjected to a shear sweep which can be programmed in the software that accompanies the Rheometer. The data acquired from the computer is processed and plotted as desired. [0083] FIG. 1 shows the viscosity analyses of three exemplary gels and, for comparison, a guar gel. Example 2 Charge-Viscosity Analysis of Exemplary Dry and Emulsion Glyoxal-Crosslinked-Polymer Gels [0084] The compositions were prepared by adding 200 mL of 2% KCl to a Waring blender jar. 0.3% of active acrylamide copolymer was added along with the pH buffer and mixed for a few minutes. 0.33% glyoxal was added (to provide a molar ratio of glyoxal to monomer of about 1.35) and blended for a few seconds. The obtained crosslinked gel was evaluated on an Anton Paar Physica Rheometer setup with concentric cylinder geometry. The gel was sheared at a constant shear rate of 100 s −1 and at a temperature of 180° F. The viscosity reported in the table is an average reading measured over 30 minutes. [0085] Analysis of Charge-Viscosity was evaluated for a range of dry PAM (DPAM), partially hydrolyzed PAM (HYPAM) and emulsion PAM (EPAM) polymers. Series were arranged in three groups with increasing charges for each group. [0000] TABLE 2 Viscosity of Exemplary Dry and Emulsion Glyoxal-Crosslinked-Polymer Gels Sample# Product Form Charge (mole %) Viscosity (cP) 1 DPAM 2 5 2 DPAM 13 463 3 DPAM 23 343 4 DPAM 33 33 5 DPAM 53 14 6 HYPAM 3 18 7 HYPAM 10 677 8 HYPAM 15 1326 9 HYPAM 20 463 10 HYPAM 30 118 11 HYPAM 40 57 12 EPAM 5 44 13 EPAM 10 412 14 EPAM 15 818 15 EPAM 20 475 16 EPAM 30 306 17 EPAM 40 32 [0086] Conditions: 0.3% active polymer, crosslinked with 0.33% glyoxal, in 2% KCl solution. [0087] Based on viscosity under the testing conditions (shear rate 100 sec −1 at 180F), there is an influence of charge on gel viscosity and performance. An optimum range of the charge appears to be in the 15-20 mole % range. This charge effect is unexpected because one would expect to have increasingly better performance (viscosity) with decreasing charge (which means more acrylamide units available for the crosslinking reaction with glyoxal). To the contrary, an optimum range of the charge appears to be in the 15-20 mole % range. The results of the charge-viscosity analysis are shown graphically in FIG. 2 . Example 3 Static Proppant Settling of PAM Versus Guar [0088] The Static Proppant Settling Column test was used to evaluate settling time of proppants in PAM. This test used a 250 mL graduated cylinder with a proppant loading of 4 lb/gal with a 20/40 mesh. Proppant was blended with the crosslinked PAM using a blender for 10-30 seconds until well mixed. The downward mobility was measured as a function of time. [0000] Sample Correla- Fluid tion to Initial Final containing Viscosity height height Sand suspended Table in Time of sand of sand height proppant Example 1 Type (hours) (mL) (mL) (%) (%) 2 DPAM 0.5 100 100 0 100 17 100 100 0.00 100.00 3 DPAM 0.5 100 100 0 100 17 100 80 20.00 80.00 14 EPAM 0.5 100 100 0 100 17 100 100 0.00 100.00 15 EPAM 0.5 100 100 0 100 17 100 100 0.00 100.00 8 HYPAM 0.5 100 100 0 100 17 100 100 0.00 100.00 9 HYPAM 0.5 100 100 0 100 17 100 100 0.00 100.00 Guar 0.5 100 100 0 100 17 100 100 67 33 [0089] The results of this analysis demonstrate the ability of proppant to remain suspended in the polymer fluid.

Gel compositions comprising an acrylamide polymer or copolymer crosslinked with dialdehyde, methods to produce the gel compositions, welibore treatment fluids comprising the gel compositions, and methods of treating a well bore comprising injecting the gel compositions, are provided. In the drilling, completion, and stimulation of oil and gas wells, well treatment fluids are often pumped into well bore holes under high pressure and at high flow rates causing the rock formation surrounding the well bore to fracture.

BACKGROUND OF THE INVENTION This invention relates to the discovery that a selected group of novel carbamoylphosphonates can be used to regulate the growth rate of plants. More particularly, the compounds of this invention are useful for controlling the growth of woody vegetation. Related compounds such as the dialkyl carbamoylphosphonates are disclosed in U.S. Pat. No. 3,005,010 as herbicides. SUMMARY OF THE INVENTION In summary, this invention relates to a novel group of carbamoylphosphonates, the method of using the carbamoylphosphonates to regulate the growth rate of plants and formulations containing carbamoylphosphonates which are useful to regulate the growth rate of plants. More particularly, the carbamoylphosphonates of this invention are represented by the formula: ##STR1## wherein: R 1 is alkyl of 1 through 6 carbon atoms, chloroalkyl of 1 through 6 carbon atoms containing up to three chlorine atoms, bromoalkyl of 1 through 6 carbon atoms containing up to 3 bromine atoms, alkoxy alkyl of 3 through 7 carbon atoms, alkenyl of 2 through 6 carbon atoms, alkynyl of 3 through 4 carbon atoms, phenyl or benzyl; R 2 is hydrogen or methyl; R 3 is hydrogen, methyl, amino, methylamino, or dimethylamino; R 2 and R 3 can be taken together to form a ring selected from --(CH 2 ) 2 --O--(CH 2 ) 2 -- or --(CH 2 ) n -- where n is 2-6; M is selected from the group consisting of ammonium, hydrogen, sodium, lithium, potassium, calcium, magnesium, zinc, manganese, barium or ##STR2## where R 6 , R 7 and R 8 can be the same or different and each can be hydrogen, alkyl of 1 through 4 carbon atoms, or hydroxy alkyl of two through 4 carbon atoms; and R 9 is hydrogen, alkyl of one through twelve carbon atoms, allyl, benzyl, amino, methylamino, or dimethylamino; R 6 and R 7 can be taken together to form a ring that is --(CH 2 ) 2 --O--(CH 2 ) 2 -- or --(CH 2 ) n -- where n is 2-6 and R 8 and R 9 are H. Preferred compounds of this invention include those compounds of formula (1) where R 1 is alkyl of one through four carbons or alkenyl of three through four carbons; R2 and R3 are each hydrogen; and M is ammonium, hydrogen, or alkali metal such as sodium, lithium or potassium. The most preferred compounds of this invention are ammonium allyl carbamoylphosphonate, ammonium ethyl carbamoylphosphonate, and ammonium isopropyl carbamoylphosphonate. Another aspect of this invention relates to the method for modifying the growth rate of plants which comprises applying an effective amount of a compound of formula (1) to a plant to effect modification of the growth rate of said plant. Specifically, the method of this invention results in retarding the growth rate of the treated plants. Another aspect of this invention relates to formulations of compounds of formula (1) with suitable agricultural adjuvants and modifiers or with tree wound dressings. DESCRIPTION OF THE INVENTION This invention is founded on the discovery that the compounds of formula (1) are useful for modifying the growth rate of plants. In this regard, it has been noted that the compounds of this invention, as represented by formula (1), are particularly useful to retard the growth rate of plants without killing them. The compounds of this invention are particularly useful to retard the growth of woody plants. The compounds of this invention can, therefore, be applied in areas such as power line rights-of-way where low-growing and slow growing vegetation is especially desirable. In addition to their value as plant growth retardants the compounds of this invention can also be used to control flowering, fruit set and coloration on apples and other fruits. They are useful to control the growth and flowering of ornamental species such as chrysanthemum and azalea. The compounds of this invention can also be used to prolong the dormancy of perennial plants, and thereby protect the unsprouted buds from frost damage. This can be especially important in the protection of flower buds, which in some years, may sprout early and be killed by cold temperatures. PREPARATION The ammonium carbamoylphosphonate salts of this invention are readily prepared by the interaction of the diesters of carboalkoxyphosphonic acids with aqueous solutions of ammonia, primary amines or secondary amines. The reaction can be considered to occur in two steps as is illustrated by the following equations. ##STR3## In equations (2) and (3) R is alkyl of 1 through 6 carbon atoms, chloroalkyl of 1 through 6 carbon atoms containing up to 3 chlorine atoms, bromoalkyl of one through 6 carbon atoms containing up to 3 bromine atoms, alkoxy alkyl of from 3 through 7 carbon atoms, alkenyl of 2 through 6 carbon atoms, alkynyl of 3 through 4 carbon atoms, phenyl or benzyl; R 10 is alkyl of 1 through 4 carbon atoms, preferably methyl or ethyl; R 1 is alkyl of 1 through 6 carbon atoms, chloroalkyl of 1 through 6 carbon atoms containing up to 3 chlorine atoms, bromoalkyl of 1 through 6 carbon atoms containing up to 3 bromine atoms, alkoxy alkyl of 3 through 7 carbon atoms, alkenyl of 2 through 6 carbon atoms, alkynyl of 3 through 4 carbon atoms, phenyl or benzyl; R 2 is hydrogen or methyl; R 3 is hydrogen, methyl, amino, methylamino, or dimethylamino; R 2 and R 3 can be taken together to form a ring selected from --(CH 2 ) 2 --O--(CH 2 ) 2 -- or --(CH 2 ) n -- where n is 2-6;M is selected from the group consisting of ammonium, hydrogen, sodium, lithium, potassium, calcium, magnesium, zinc, manganese, barium or ##STR4## where R 6 , R 7 and R 8 can be the same or different and each can be hydrogen, alkyl of 1 through 4 carbon atoms, or hydroxy alkyl of 2 through 4 carbon atoms; and R 9 is hydrogen, alkyl of 1 through 12 carbon atoms, allyl, benzyl, amino, methylamino, or dimethylamino; R 6 and R 7 can be taken together to form a ring that is --(CH 2 ) 2 --O--(CH 2 ) 2 -- or --(CH 2 ) n -- where n is 2-6 and R 8 and R 9 are H. The synthesis method, exemplified by equations (2) and (3) involves concurrent or consecutive aminolysis and hydrolysis of the starting dialkyl carboalkoxyphosphonate by interaction with water and the amine reactant. While equations (2) and (3) represent the route predominantly taken by the reaction when combined in one operation, some hydrolysis may occur during or before aminolysis. However, the postulated reaction as represented by equations (2) and (3) favoring formation of the carbamoylphosphonate intermediate is proved experimentally, as it is possible in some instances to isolate the carbamoylphosphonate intermediate shown as the product of equation (2). It has, of course, also been experimentally demonstrated that the product of equation (3) is in fact obtained. An alternate method for synthesis of those compounds of this invention where R 1 is substituted by chlorine or bromine consists of the addition of halogen or hydrogen halide to the double bond of the compounds of this invention where R 1 is alkenyl. This reaction is illustrated by equation (4). ##STR5## The dialkyl carbamoylphosphonates prepared as described above or by methods described in the chemical literature are readily hydrolized to the monoester salt compounds of this invention by addition to aqueous ammonia or amine solutions. This procedure may be used therefore to obtain a "mixed" product, comprising a salt of one amine and an amide of another. This will be discussed and exemplified below. The dialkyl carboalkoxyphosphonates and dialkyl carbamolyphosphonates used for the synthesis of the compounds of this invention can be prepared by methods available in the literature, such as Nylen, Chem. Ber. 57, 1023 (1924) and Reetz et al., J.A.C.S. 77, 3813-16 (1955) using appropriate ester intermediates. Generally, the alkoxy group of the carboalkoxyphosphonate is limited for practical purposes to methyl and ethyl, since there appears to be no advantage to increasing the size of the alcohol moiety. However, higher alcohol derivatives are useful in some instances. The following are illustrative of typical diesters of the carboalkoxyphosphonates: Diethyl carbomethoxyphosphonate Diallyl carbomethoxyphosphonate Diisopropyl carboethoxyphosphonate Dibutyl carbobutoxyphosphonate Dimethallyl carboethoxyphosphonate The following are illustrative of typical carbamoylphosphonate esters: Diethyl carbamoylphosphonate Diallyl N,N-dimethylcarbamoylphosphonate Diallyl carbamoylphosphonate Dipropyl N-methylcarbamoylphosphonate Dimethyl piperidinocarbonylphosphonate The following are illustrative of the amines which can be used for the amination and/or hydrolysis of the esters: Ammonia Methylamine Dimethylamine Allylamine Propylamine Ethylamine Morpholine Piperidine Methylhydrazine N,n-dimethylhydrazine Ethanolamine More particularly, in the preferred procedure for preparing the ammonium alkyl carbamoylphosphonates of this invention, a dialkyl carboalkoxyphosphonate or dialkyl carbamoylphosphonate is added to a stirred aqueous solution of ammonia or other amine. Stirring is contained until a clear solution is obtained. The resultant salt can then be isolated by removal of the water through evaporation or by stripping under reduced pressure. In general, these salts are stable white crystalline solids or viscous liquids. Those which are solid can be recrystallized from one or a mixture of several lower alcohols. However, most of the products are suitable for use without purification. It is preferred that an excess of ammonia or amine be employed in this reaction to insure good yields and rapid reaction. A ratio of diester to amine of 1 to 2 or greater is employed. Preferably the ratio of diester to amine of between 1 to 2 and 1 to 10 is employed. The excess amine insures that amidation of the carboxylic ester rather than hydrolysis is the predominant reaction. It is also preferred that a concentration of ammonia or amine of from 25 to 50% be employed, although the reaction can be operated at higher or lower concentrations. When the amine reactant is not highly soluble in water, another solvent, such as methanol or ethanol can be added to the aqueous system to solubilize the amine reactant and thereby increase its reactivity. This process can conveniently be carried out at about room temperature, although higher temperatures can also be employed if it is desired to speed up the rate of reaction. This process is moderately exothermic, and therefore must be controlled by regulation of the diester addition rate and/or by external cooling to maintain the desired temperature. A highly satisfactory procedure is to slowly add the diester to a stirring aqueous solution of the amine which is cooled and maintained at about 15° C. When addition of the diester is complete, the temperature of the mixture is allowed to come to room temperature or slightly above. Generally, the reaction is complete in a few minutes to several hours depending on the reactants and conditions used. The ammonium salts prepared as described above can be converted to salts of other bases or of alkaline and alkaline earth metals by interchanging the ammonium salt with appropriate bases or salts. Another method is to convert the ammonium salt to the free acid, and then neutralize the free acid with the appropriate base or salt. The following illustrative examples are presented to further illustrate this invention. In the following examples, parts and percentages are by weight unless otherwise specified. EXAMPLE 1 A solution of 48.5 parts of 29% aqueous ammonium hydroxide is stirred and cooled with an external ice bath to 15° C. To the cooled solution 22 parts of diallyl carbomethoxyphosphonate is slowly added over a ten-minute period. The mixture turns cloudy, but clears up after about 15 minutes. During this time, the mixture is allowed to warm spontaneously to about 30° C. and stirring is continued for two hours. The clear solution is stripped under reduced pressure (15 mm of Hg) at a water-bath temperature or 70° C. The residue is a white crystalline solid which is recrystallized from absolute ethyl alcohol, giving 12.3 parts of ammonium allyl carbamoylphosphonate, m.p. 160-162.5° C. Nonaqueous titration either as an acid or a base gives a molcular weight of 182±1. EXAMPLE 2-19 The procedure of Example 1 is repeated by substituting an equivalent amount of the indicated "Phosphonate Ester" for the diallyl carbomethoxyphosphonate of Example 1 to produce the indicated "Salt Product." __________________________________________________________________________Ex. Phosphonate Ester Salt Product__________________________________________________________________________ 2 diethyl carbomethoxyphosphonate ammonium ethyl carbamoylphosphonate, m.p. 173-176 3 bis(2-chloroethyl)carbobutoxy- ammonium 2-chloroethyl phosphonate carbamoylphosphonate, m.p. 117-120 4 dibutyl carboethoxyphosphonate ammonium butyl carbamoylphosphonate m.p. 205.5-206.5 5 diallyl carboethoxyphosphonate ammonium allyl carbamoylphosphonate 6 dimethallyl carbomethoxy- ammonium methallyl phosphonate carbamoylphosphonate, m.p. 193-197 7 diisopropyl carboethoxyphosphon- ammonium isopropyl car- ate bamoylphosphonate, m.p. 213-216 (dec.) 8 dimethyl carbomethoxyphosphonate ammonium methyl car- bamoylphosphonate, m.p. 148-151 9 dipropyl carbopropoxyphosphonate ammonium propyl carbomyl- phosphonate, m.p. 190- 192 (dec.)10 diisobutyl carbomethoxy- ammonium isobutyl car- phosphonate bamoylphosphonate, m.p. 221-222 (dec.)11 dihexyl carbomethoxyphosphonate ammonium hexyl carbamoyl- phosphonate, m.p. 212 (dec.)12 bis(1-ethyl-2-butenyl)car- ammonium (1-ethyl-2- bomethoxyphosphonate butenyl)carbamoylphosphon- ate13 bis(2-methoxyethyl)carbomethoxy- ammonium 2-methoxyethyl phosphonate carbamoylphosphonate14 bis(2-bromopropyl)carbomethoxy- ammonium 2-bromopropyl phosphonate carbamoylphosphonate15 bis(6-chlorohexyl)carbomethoxy- ammonium 6-chlorohexyl phosphonate carbamoylphosphonate16 bis(6-bromohexyl)carbomethoxy- ammonium 6-bromohexyl phosphonate carbamoylphosphonate17 bis(2-butoxyethyl)carbomethoxy- ammonium 2-butoxyethyl phosphonate carbamoylphosphonate, hygroscopic acid18 bis(2,2,2-trichloroethyl)carbo- ammonium 2,2,2-trichloro- methoxyphosphonate ethylcarbamoylphosphonate19 bis(2,2,2-tribromoethyl)carbo- ammonium 2,2,2-tribromo- methoxyphosphonate ethylcarbamoylphosphonate__________________________________________________________________________ EXAMPLE 20 To a stirring ice-chilled solution of 35 parts 40% methylamine in water is added slowly 8.4 parts od dimethyl carbomethoxyphosphonate. The mixture is warmed to 25° C. and allowed to stir for 3 hours. The clear solution on stripping under reduced pressure yields 9.6 parts methylammonium methyl N-methylcarbamoylphosphonate as a colorless oil. The product analyzes for the dihydrate. EXAMPLES 21-27 The procedure of Example 20 is repeated substituting an equivalent amount of the indicated "Aqueous Amine" for the methylamine of Example 20 and an equivalent amount of the indicated "Phosphonate Ester" for the dimethylcarbomethoxyphosphonate of Example 20 to obtain the indicated Salt Product. Most of the indicated Salt Products are isolated as liquids or low melting solids. __________________________________________________________________________Ex. Aqueous Amine Phosphonate Ester Salt Product__________________________________________________________________________21 methylamine (40%) diethyl carboethoxy- methylammonium phosphonate ethyl N-methyl- carbamoylphos- phonate22 methylamine (40%) diisopropyl carbo- methylammonium methoxyphosphonate isopropyl N- methylcarbamoyl phosphonate23 methylamine (40%) diallyl carboethoxy- methylammonium phosphonate allyl N-methyl- carbamoylphos- phonate24 dimethylamine (25%) diethyl carbomethoxy- dimethylammonium phosphonate ethyl N,N- dimethylcarbamoyl phosphonate25 methylhydrazine (50%) diethyl carboethoxy- methyl carbazoyl- phosphonate phosphonic acid monoethyl ester salt with methyl- hydrazine26 piperidine (50%) dibenzyl carbomethoxy- piperidinium phosphonate benzyl piper- idinocarbonyl- phosphonate27 1,1-dimethyl- dipropyl carbomethoxy- 1,1-dimethyl hydrazine (35%) phosphonate hydrazinium propyl 3,3-dimethylcar- bazoylphosphonate__________________________________________________________________________ EXAMPLE 28 Eight parts of diethyl N-methylcarbamoylphosphonate is added slowly to 18 parts of a 29% aqueous solution of ammonia, while holding the temperature at 25° C. by external cooling. The unreacted ammonium hydroxide is allowed to evaporate, giving a white, crystalline, solid residue. Recrystallization from absolute ethanol gives 5 parts of ammonium ethyl N-methylcarbamoylphosphonate, m.p. 189° C. EXAMPLES 29-41 The procedure of Example 28 is repeated substituting an equivalent amount of the indicated Aqueous Amine for the ammonia of Example 28 and an equivalent amount of the indicated Phosphonate Ester for the diethyl methylcarbamoylphosphonate of Example 28 to obtain the indicated Salt Product. __________________________________________________________________________Ex. Aqueous Amine Phosphonate Ester Salt Product__________________________________________________________________________29 ammonia (20%) diphenyl N-methyl ammonium phenyl carbamoylphosphonate N-methyl carbamoylphos- phonate30 methylamine (25%) dimethyl N,N-dimethyl methylammonium carbamoylphosphonate methyl N,N-di- methylcarbamoyl- phosphonate31 dimethylamine (25%) diethyl carbamoyl- dimethylammonium phosphonate ethyl car- bamoylphosphonate32 allylamine (25%) diallyl carbamoyl- allylammonium phosphonate allyl car- bamoylphosphonate33 isobutylamine (20%) diisopropyl N-methyl isobutylammonium carbamoylphosphonate isopropyl N- methylcarbamoyl- phosphonate34 methylamine (20%) diisopropyl morpholino- methylammonium carbonylphosphonate isopropyl morpholinocar- bonylphosphonate35 triethanolamine diallyl carbamoyl- triethanol- phosphonate ammonium allyl carbamoylphos- phonate36 ammonia (29%) diethyl pyrrolidino- ammonium ethyl carbonylphosphonate pyrrolidinocar- bamoylphosphon- ate, m.p. 189- 192 (dec.)37 ammonia (29%) diethyl morpholino- ammonium ethyl carbonylphosphonate morpholinocar- bonylphosphon- ate, m.p. 183- 185 (dec.)38 ammonia (29%) diethyl N,N-dimethyl- ammonium ethyl carbamoylphosphonate N,N-dimethylcar- bamoylphosphon- ate, m.p. 140.5- 142.539 ammonia (29%) bis(3-butynyl)N,N-di- ammonium 3-butynyl methylcarbamoyl- N,N-dimethylcar- phosphonate bamoylphosphon- ate40 ammonia (29%) diethyl N-methylcar- ammonium ethyl N- bamoylphosphonate methylcarbamoyl- phosphonate41 ammonia diethyl aziridinium- ammonium ethyl carbamoylphosphonate aziridiniumcar- bamoylphosphon- ate__________________________________________________________________________ EXAMPLE 42 To a mixture of 12.1 parts of ammonium allylcarbamoylphosphonate and 100 parts of ethanol is added dropwise 8 parts of bromine. The reaction mixture is filtered giving 8.5 parts of ammonium 2,3-dibromopropyl carbamoylphosphonate, m.p. 175-177° C. EXAMPLES 43-44 The procedure of Example 42 is repeated substituting an equivalent amount of the indicated "Alkenyl Reagent" for the ammonium allylcarbamoylphosphonate of Example 42 and an equivalent amount of the indicated "Halogen" for the bromine of Example 42 to obtain the indicated "Product". ______________________________________43 ammonium methallyl chlor- ammonium 2,3-dichloro- carbamoylphosphonate ine 2-methylpropyl carbam- oylphosphonate44 ammonium but-2-enyl bro- ammonium 2,3-dibromobutyl carbamoylphosphonate mine carbamoylphosphonate______________________________________ EXAMPLE 45 An aqueous solution of 45 parts ammonium hydroxide is stirred and chilled with an ice bath, while 24.4 parts benzyl methyl carbomethoxyphosphonate is added slowly. Stirring is continued until a clear solution is obtained. Unreacted ammonium hydroxide and water are removed from the mixture under reduced pressure, leaving as a solid residue ammonium monobenzyl carbamoylphosphonate, m.p. 186, after recrystallization from ethanol. EXAMPLES 46-51 The procedure of Example 45 is repeated substituting an equivalent amount of the indicated Aqueous Amine for the ammonium hydroxide of Example 45 and an equivalent amount of the indicated Phosphonate Ester for the benzyl methyl carbomethoxyphosphonate of Example 45 to obtain the indicated Salt Product as a principal product of this procedure. ______________________________________Aqueous PhosphonateEx. Amine Ester Salt Product______________________________________46 methylamine benzyl methyl methylammonium(40%) carbomethoxy- benzyl N-methyl- phosphonate carbamoylphosphonate47 ammonia methyl phenyl ammonium phenyl car-(29%) carbomethoxy- bamoylphosphonate, phosphonate m.p. 197-199 (dec.)48 dimethylamine butyl ether dimethylammonium(25%) carbomethoxy- butyl N,N-dimethyl- phosphonate carbamoylphosphonate49 ethylamine methyl ethylammonium propargyl(50%) propargyl N-ethylcarbamoyl- carbomethoxy- phosphonate phosphonate50 allylamine methyl allyl allylammonium allyl N-(25%) carboethoxy- allyl carbamoylphosphon- phosphonate ate51 pyrrolidine methyl propyl pyrrolidinium propyl(30%) carbomethoxy- pyrrolidinecarbonyl- phosphonate phosphonate______________________________________ EXAMPLE 52 To a stirring suspension of 21.2 parts ammonium butyl N-methylcarbamoylphosphonate and 100 parts methanol is added 42 parts of a 40% solution of N-benzyltrimethylammonium hydroxide in methanol. Ammonia and methanol are stripped from the mixture at 40° C. under reduced pressure, leaving benzyltrimethylammonium butyl N-methylcarbomoylphosphonate as a residue. EXAMPLES 53-56 The procedure of Example 52 is repeated substituting an equivalent amount of the indicated "Base" for the N-benzyltrimethylamonium hydroxide of Example 52 and an equivalent amount of the indicated Ammonium Phosphonate for the ammonium butyl N-methylcarbamoylphosphonate of Example 52 to obtain the indicated Salt Product. ______________________________________ AmmoniumEx. Base Phosphonate Salt Product______________________________________53 tetraethyl- ammonium allyl tetraethylammoniumammonium carbamoylphosphonate monoallyl carbamoyl-hydroxide phosphonate54 trimethyl- ammonium ethyl trimethylammoniumamine N-methylcarbamoyl- monoethyl N-methyl(large phosphonate carbamoylphosphonateexcess)55 ethanol- ammonium methallyl ethanolammoniumamine hexahydroazepino- methyallyl hexahydro- carbonylphosphonate azepinocarbonylphos- phonate56 benzyl- ethylammonium iso- benzylammonium iso-amine propyl carbam- propyl carbamoyl oylphosphonate phosphonate______________________________________ EXAMPLE 57 A 5% aqueous solution of ammonium ethyl carbamoylphosphonate is passed through a packed column of sulfonated polystyrene copolymer hydrogen-type resin to convert the salt to the free acid. Evaporation of the water gives a residue of the acid ester, ethyl carbamoylphosphonic acid, m.p. 130° C. EXAMPLES 58-60 The procedure of Example 57 is repeated, first obtaining the indicated "Acid Ester" in aqueous solution and then removing the water to obtain the water-free product, usually a solid. ______________________________________Ex. Ammonium Phosphonate Acid Ester______________________________________58 ammonium methyl N-methylcar- methyl N-methylcarbamoyl-bonylphosphonate phosphonic acid59 ammonium isopropyl carbamoyl- isopropyl carbamoyl-phosphonate phosphonic acid60 ammonium alkyl carbamoyl- alkyl carbamoyl-phosphonate phosphonic acid______________________________________ EXAMPLE 61 A 5% aqueous solution of ammonium propyl N-methylcarbamoylphosphonate is passed through a packed column of sulfonated polystyrene copolymer type resin to convert the salt to the free acid. This is neutralized with the equivalent amount of sodium bicarbonate to give a solution of essentially pure sodium propyl N-methylcarbamoylphosphonate. Evaporation of this solution gives the solid salt product. EXAMPLES 62-75 The procedure of Example 61 is repeated, first obtaining the free acids of the indicated Ammonium Phosphonate as was done in Example 61 and then neutralizing the acid with the indicated Base according to the procedure of Example 61 to obtain the indicated Salt Product. __________________________________________________________________________ AmmoniumEx. Phosphonate Base Salt Product__________________________________________________________________________62 ammonium phenyl sodium bicarbonate sodium phenyl carbamoylphos- carbamoylphos- phonate phonate63 ammonium benzyl calcium hydroxide hemicalcium benzyl carbamoylphos- carbamoylphosphonate phonate64 ammonium ethyl barium hydroxide hemibarium ethyl carbamoylphos- carbamoylphosphonate phonate65 ammonium methyl- hydroxyethyltri- hydroxyethyltri- N,N-dimethyl- methylammonium methylammonium carbamoyl phos- hydroxide methyl N,N-dimethyl phonate carbamoylphosphonate66 ammonium benzyl benzyltrimethyl- benzyltrimethyl- carbamoylphos- ammonium hydroxide ammonium benzyl phonate carbamoylphosphonate67 ammonium allyl magnesium hydroxide hemimagnesium allyl carbamoylphos- carbamoylphosphonate phonate68 ammonium butyl morpholine morpholinium N-methyl carbam- butyl N-methyl- oylphosphonate carbamoylphosphonate69 ammonium mono- trimethylamine trimethylammonium isopropyl morpho- isopropyl morpholino- lino-carbonyl- carbonylphosphonate phosphonate70 ammonium ethyl tetrabutylammonium tetrabutylammonium carbamoyl- hydroxide ethyl carbamoyl- phosphonate phosphonate, hygroscopic solid71 ammonium ethyl lithium carbonate lithium ethyl carbamoylphos- carbamoylphosphon- phonate ate, m.p. above 300° C.72 ammonium ethyl zinc carbonate hemizinc ethyl car- carbamoyl- bamoylphosphonate, phosphonate m.p. 244 (dec.)73 ammonium iso- dodecylamine dodecylammonium propyl car- isopropyl carbamoyl bamoylphos- phosphonate phonate74 ammonium allyl manganous car- hemimanganous allyl carbamoylphos- bonate carbamoylphosphon- phonate ate75 ammonium butyl dodecyltrimethyl dodecyltrimethyl- morpholinumcar- ammonium hydroxide ammonium butyl bonylphosphonate morpholiniumcarbony phosphonate__________________________________________________________________________ EXAMPLE 76 To a stirred solution of 10 parts of potassium bicarbonate and 50 parts of water is added 18.4 parts ammonium isobutyl carbamoylphosphonate. Stirring is continued until solution is complete. The solution is evaporated to dryness, giving the solid product, potassium isobutylcarbamoylphosphonate. EXAMPLES 77-80 The procedure of Example 76 is repeated substituting the indicated "Bicarbonate Salt" for the potassium bicarbonate of Example 76 and an equivalent amount of the indicated "Carbamoylphosphonate" for the ammonium monoisobutyl carbamoylphosphonate of Example 76 to obtain the indicated Salt Product. ______________________________________Bicarbonate Carbamoyl-Ex. Salt phosphonate Salt Product______________________________________77 sodium ammonium ethyl N- sodium ethyl N-bicarbonate methylcarbamoyl- methylcarbamoyl- phosphonate phosphonate78 potassium ammonium benzyl potassium benzylbicarbonate carbamoylphos- carbamoylphosphonate phonate79 tetramethyl- ammonium mono- tetramethylammoniumammonium allyl piperidino- allyl piperidino-bicarbonate carbonylphos- carbonylphosphonate phonate80 benzyltri- ammonium butyl benzyltri-methyl- carbamoylphos- methylammonium butylammonium phonate carbamoylphosphonatebicarbonate______________________________________ Formulation Plant growth modifying compositions of the present invention can be prepared by admixing at least one of the compounds of this invention with pest control adjuvants or modifiers ot provide compositions in the form of dusts, water-soluble powders, solutions, granules or pellets. In addition, the plant growth modifying agents such as maleic hydrazide and "Alar" (N-dimethylaminosuccinamic acid) can be included in the compositions of this invention in combination with the compounds of this invention. Compositions of the invention, may contain as a conditioning agent one or more surface-active agents, sometimes called surfactants, in amounts sufficient to render a given composition containing the compounds of this invention readily soluble in water or capable of wetting foliage efficiently. The surface-active agent used in this invention can be a wetting, dispersing or an emulsifying agent which will assist dispersion and solution of the active compound. The surface-active agent or surfactant can include such anionic, cationic and non-ionic agents as have heretofore been generally employed in plant control compositions of similar type. Suitable surface-active agents are set forth, for example in "Detergents and Emulsifiers" 1976 Annual by John W. McCutcheon, Inc. In general, less than 10% by weight of the surface-active agent will be used in compositions of this invention and ordinarily the amount of surface-active agents will range from 1-5% but may even be less than 1% by weight. Additional surface-active agents can be added to the formulations to increase the ratio of surfactant:active ingredient up to as high as 5:1 by weight. Such compositions may have a greater effectiveness than can be expected from a consideration of the activity of the components used separately. When used at higher rates, it is preferred that the surfactant be present in the range of one-fifth to five parts surfactant for each one part of active agent. Water-Soluble Powders Water-soluble powders are compositions containing the water-soluble active material, an inert solid extender which may or may not be water-soluble, and optionally one or more surfactants to provide rapid wetting and solution. A buffer, which may also function as an extender, can be present to improve formulation stability and to control the pH of the final spray solution. The classes of extenders suitable for the water-soluble powder formulations of this invention are the natural clays, diatomaceous earth, synthetic mineral fillers derived from silica and silicate, starch, sugar, and inorganic salts. Most preferred fillers for this invention are kaolinites, attapulgite clay, montmorillonite clays, synthetic silicas, synthetic magnesium silicate, calcium sulfate dihydrate, and disodium hydrogen phosphate. Suitable surfactants for use in such compositions are those listed by J. W. McCutcheon in Detergents and Emulsifiers 1967 Annual. Among the more preferred surfactants are the non-ionic and anionic type, and those most suitable for the preparation of the dry, soluble products of this invention are solid forms of compounds known to the art as wetters and dispersants. Occasionally a liquid, non-ionic compound classified primarily as an emulsifier may serve as both wetter and dispersant. Most preferred wetting agents are alkylbenzene- and alkylnaphthalene-sulfonates, sulfated fatty alcohols, amines or acid amides, long-chain acid esters of sodium isethionate, esters of sodium sulfosuccinate, sulfated or sulfonated fatty acids esters, petroleum sulfonates, sulfonated vegetable oils, and ditertiary acetylenic glycols. Preferred dispersants are methylcellulose, polyvinyl alcohol, lignin sulfonates, polymeric alkylnaphthalenesulfonates, sodium naphthalenesulfonate, polymethylene bisnaphthalenesulfonate, and sodium N-methyl-N-(long chain acid) taurates. Wetting and dispersing agents in these preferred water-soluble compositions of this invention are usually present at concentrations of from about 0.5 weight percent to 5 weight percent. The inert extender then completes the formulation. Where needed, 0.1 weight percent to 1.0 weight percent of the extender may be replaced by a corrosion inhibitor or an anti-foaming agent or both. Thus, water-soluble formulations of the invention will contain from about 25 to 95 weight percent active material, from 0.5 to 2.0 weight percent wetting agent, from 0.25 to 5.0 weight percent dispersant, and from 4.25 to 74.25 weight percent inert extender, as these terms are described above. When the water-soluble powder contains a corrosion inhibitor or an anti-foaming agent or both, the corrosion inhibitor will not exceed about 1 percent of the composition, and the anit-foaming agent will not exceed about 0.5 percent by weight of the composition, both replacing equivalent amounts of the inert extender. Solution Concentrates The aqueous solution concentrates are prepared by mixing a water-soluble active compound of this invention with water. A portion of the water may be replaced with methanol, ethanol, isopropanol, ethylene gylcol, cellosolve or methyl cellosolve. Surfactants and buffering agents can optionally be present. These aqueous solution concentrates will contain from 15 to 60% of active ingredient, and from 40 to 85% water or mixture of water and hydroxylated organic solvent. Surfactants, corrosion inhibitors, buffering and antifoam agents may also be included in which case they may replace up to 10% of the solvent system. Dusts Dusts are dense powder compositions which are intended for application in dry form, in accordance with the preferred compositions and methods of the invention. Dusts are characterized by their free-flowing and rapid settling properties so that they are not readily windborne to areas where their presence is not desired. They contain primarily an active material and a dense, free-flowing, solid extender. Their performance is sometimes aided by the inclusion of a wetting agent, and convenience in manufacture frequently demands the inclusion of an inert, adsorptive grinding aid. For the dust compositions of this invention, the inert extender may be either of vegetable or mineral origin, the wetting agent is preferably anionic or non-ionic and suitable adsorptive grinding aids are of mineral origin. Suitable classes of inert solid extenders for use in the dust compositions are those organic or inorganic powders which possess high bulk density and are very free-flowing. They are also characterized by possessing relatively low surface areas and are poor in liquid adsorption. Suitable classes of grinding aids are natural clays, diatomaceous earths, and synthetic mineral fillers derived from silica or silicate. Among ionic and non-ionic wetting agents, the most suitable are the members of the group known to the art as wetting agents and emulsifiers. Although solid agents are preferred because of ease in incorporation some liquid non-ionic agents are suitable in the dust formulations. Preferred inert solid extenders for the dusts of this invention are micaceous talcs, pyrophyllite, dense kaolin clays, tobacco dust and ground calcium phosphate rock such as that known as "Phosphodust", a trademark of the American Agricultural Chemical Company. Preferred grinding aids are attapulgite clay, diatomaceous silica, synthetic fine silica and synthetic calcium and magnesium silicate. Preferred wetting agents are those previously described under water-soluble powder formulations. The inert solid extenders in the dusts of this invention are usually present in concentrations of from about 30 to 90 weight percent of the total composition. The grinding aid will usually constitute 5 to 50 weight percent of the composition, and the wetting agent will constitute from about 0 to 1.0 weight percent of the composition. Dust compositions can also contain other surfactants such as dispersing agents in concentrations of up to about 0.5 weight percent. The water-soluble powders described above can also be used in the preparation of dusts. While such water-soluble powders could be used directly in dust form, it is more advantageous to dilute them by blending with the dense dust diluent. In this manner, dispersing agents, corrosion inhibitors, and anti-foam agents may also be found as components of a dust. Thus, the dust compositions of this invention will comprise about 5 to 20 weight percent active material, 5 to 50 weight percent adsorptive filler, 0 to 1.0 weight percent wetting agent, and about 30 to 90 weight percent dense, free-flowing dust diluent, as these terms are used herein. Such dust formulations can contain, in addition, minor amounts of dispersants, corrosion inhibitors, and anti-foam agents, derived from the water-soluble powders used to make the dusts. Granules and Pellets Under some circumstances it may be advantageous to apply the compounds of this invention in the form of granules or pellets. Suitable carriers are natural clays, some pyrophyllites and vermiculites. Wetting agents of the type listed by J.W. McCutcheon in "Detergents and Emulsifiers" 1967 Annual can also be present to aid leaching of the active component. One method of preparation suitable for both granules and pellets involves blending the active ingredient with clays, water-soluble salts, surfactants and a small amount of water. After pelleting and/or granulating, the formulation is dried prior to use. A second method suitable for the preparation of granules formulation involves spraying a solution of the active material on porous, adsorptive, preformed clay or vermiculite granules. Surfactants listed by McCutcheon can also be included in the spray solution. After drying, the granules are ready for application. The preferred granules or pellets will contain about 5 to 30 weight percent of active material, about 0 to 5 weight percent wetting agent and about 65 to 95 weight percent inert mineral carrier. Paints and Dressings Although the formulations described above can be used to apply the compounds of Formula (1) to cut portions of plants, it is often preferable to incorporate them in conventional tree wound dressings which are commonly used in the trade. Thus, in one step, the cut can be protected and regrowth in the pruned area can be inhibited. Having high water solubility, the compounds can readily be incorporated in the aqueous phase of conventional asphalt emulsion dressings and water based paints. At the low levels employed (1 - 5%), there is generally little effect on the physical properties of the systems, and commercial materials need not be reformulated. At relatively high levels, the active ingredient, being a salt can cause conventional emulsions to thicken or break. In the former case mere dilution with water is effective to restore physical properties; in the latter case, a salt-tolerant emulsifier must be selected. As the compounds of Formula (1) have rather low solubility in organic solvents, they must be finely ground and well dispersed to be effective in systems such as solvent-based varnishes and paints. In such systems, the active ingredient must be treated as a pigment would be. Additionally, water must be rigorously excluded, otherwise the active material will not remain well-dispersed. When packaged as an aerosol, similar considerations apply. The preferred type of formulation is an emulsion with the compound of Formula (1) in the aqueous phase and the film former, solvent and propellant system in the organic phase. Dispersions in organic systems are possible but not preferred because of difficulty in assuring adequate mixing before use, the need to rigorously exclude moisture, and the expense of assuring an adequately fine particle size. Application As stated earlier, this invention is founded on the discovery that the compounds of formula (1) are useful for modifying the growth rate of plants. More particularly the compounds of this invention are useful as plant growth retardants. They also affect the flowering and fruit set of numerous plants. The term plant growth retardant as used in this disclosure is to be understood to mean an agent which when applied to a plant or its environs will slow the growth of the plant without killing or causing extensive injury to said plant. This also includes a delaying response on bud sprouting or prolonging of the dormancy period. The compounds of this invention can be used to retard bud break and the growth of woody vegetation. The compounds of this invention can also be used to control the growth of turf and other herbaceous vegetations. The compounds of this invention can be applied as foliar sprays or as soil applications to retard the growth rate of such plants or to affect flowering and fruit set. Preferably, the compounds of this invention are applied as a foliar spray to the point of runoff although lower-volume application may also be effective. It is preferred that the application be made a short time prior to the period when maximum plant growth is anticipated, but application can also be made during the dormant stage or just after the plants have been trimmed. Or if flowering and fruit set are to be modified, the treatment is applied before, during, or shortly after flowering. To prevent bud break it is preferred that the application be made at the time the buds for the next year are being developed. For most plants this is from July to a few weeks before leaf-fall. It will be recognized that the rate of application is dependent upon the species to be treated and the results desired. In general, rates of from 0.25 to 20 kilograms per hectare are used although higher or lower rates can achieve the desired effect in some instances. The following examples are presented to further illustrate the formulation and application of the compounds of this invention. Parts and percentages in the following examples are by weight unless otherwise indicated. EXAMPLE 81 A dust having the following formula is prepared. ______________________________________Ammonium allyl carbamoylphosphonate 5.0%Talc 64.0%Attapulgite 30.0%Sodium benzenesulfonate 1.0%______________________________________ The active component is ground with the minor diluent and the surfactant to pass a 0.149 mm. screen. This material is then blended with a major diluent to form a dust composition. It will be understood that the other compounds of this invention can also be formulated in a like manner. The dust formulation of Example 81 is applied, using a helicopter, at a rate of 100 kilograms per hectare to an area under an electric power line in which the brush and trees have been freshly trimmed in spring at the time when the leaves on most of the plants are just fully expanded. The application is made in the early morning when the foliage is wet with dew or just after a rain. This treatment retards the growth of a large number of species along the right-of-way including the following species: red maple (Acer rubrum), black willow (Salix nigra), hawthorn (Crataegus spp.), sweet gum (Liquidamber styraciflua) and yellow poplar (Liriodendron tulipifera). EXAMPLE 82 A water-soluble powder of the following formula is prepared. ______________________________________Ammonium allyl carbamoylphosphonate 95.0%Synthetic silica 3.5%Disodium hydrogen phosphate 1.0%Dioctylsodium sulfosuccinate 0.5%______________________________________ The above ingredients are mixed and then ground to pass a 0.42 mm. screen. The resulting formulation is water-soluble powder, with the exception of the synthetic silica conditioning agent. The following compounds of this invention can also be formulated in like manner. Ammonium 2-chloroethyl carbamoylphosphonate Ammonium methyl carbamoylphosphonate Sodium phenyl carbamoylphosphonate Hemicalcium benzyl carbamoylphosphonate Hemibarium ethyl carbamoylphosphonate Ammonium 2,3-dibromopropyl carbamoylphosphonate Diethylammonium ethyl carbamoylphosphonate Ammonium hexyl carbamoylphosphonate Four kilograms of the water-soluble powder formulation of Example 82 is dissolved in 200 liters of water and 0.5% of a non-phytotoxic wetting agent is added. This solution is sprayed on one hectare of freshly trimmed Norway maple (Acer plantanoides) growing along struts under a power line. This treatment greatly reduces the rate of growth of the trees and extends the time interval between trimmings. The trees are not significantly injured by the treatment. The water-soluble powder of Example 82 can be dissolved in water at the rate of 2000 p.p.m. of active ingredient and applied to one acre of Virginia bunch peanuts at the time they are beginning to flower. The treatment prevents excessive vegetative growth and promotes flowering and fruit set of the treated plants. As a result of the treatment the plants are easier to harvest and dry and more high quality nuts are harvested. EXAMPLE 83 ______________________________________Ammonium ethyl carbamoylphosphonate 90%Silica aerogel 4%Sugar 6%______________________________________ The ingredients are combined, blended, crushed through a U.S.S. No. 20 sieve (0.84 mm. openings) and reblended. In mid-September, active ingredient formulated as described above was dissolved in water containing 0.2% sorbitan monolaurate and applied to the foliage of red maple (Acer rubrum), sweet gum (Liquidambar styraciflua) and green briar (Smilax spp.) at the rate of 3 kg/ha in 800 1. of water. The treatment had no apparent effect on the plants for the remainder of the season. However, the next July the treated plants had developed almost no leaves. What buds that had broken had produced only minute red-tinged leaves. Except for some tips, the bare branches were still alive. The floor beneath the treated brush was green with herbaceous vegetation. EXAMPLE 84 A wettable powder of the following formula is prepared. ______________________________________Hemibarium benzyl carbamoyl- 50.0%phosphonateMontmorrilonite 43.0%Synthetic silica 4.0%Disodium hydrogen phosphate 1.0%Sodium alkylnaphthalenesulfonate 1.0%Sodium lignin sulfonate 1.0%______________________________________ The above ingredients are mixed and then ground to pass a 0.25 mm. screen. The active ingredient in the above formulation dissolves when the composition is added to water. Twenty kilograms of the formulation of Example 84 is added to 400 liters of water and agitated until the active ingredient dissolves. This solution is then sprayed on one hectare of newly trimmed hedgerow in the spring after the leaves have expanded. This treatment greatly reduces the growth of plants growing in the hedgerow such as osage orange (Maclura pomifera), but does not seriously injure them. The hedgerow is thus kept neat with a minimum of labor expended for trimming it. EXAMPLE 85 A solution of the following formula is prepared. ______________________________________Ammonium ethyl carbamoylphosphonate 24.0%Disodium hydrogen phosphonate 1.0%Sodium laurylsulfate 0.5%Water 74.5%______________________________________ The above components are blended to form a homogeneous solution. The following compounds can be formulated in like manner. Benzyltrimethylammonium benzyl N,N-dimethylcarbamoylphosphonate Trimethylammonium ethyl N-methylcarbamoylphosphonate Methylammonium isopropyl morpholinocarbonylphosphonate Triethylammonium ethyl carbamoylphosphonate Ten kilograms of the solution prepared in Example 85 are added to 200 liters of water and applied with a fixed boom sprayer to one hectare of Kentucky bluegrass (Poa pratensis) turf growing along a highway in early June. This treatment greatly reduces the rate of growth of the bluegrass for a period of four to eight weeks and the mowing required to maintain the area in an attractive condition is reduced. EXAMPLE 86 A solution of the following formula is prepared. ______________________________________Allylammonium allyl N,N-dimethylcarbamoyl- 24.0%phosphonateTrimethylnonylpolyethyleneglycol ether 1.0%Water 20.0%Eythylene Glycol 55.0%______________________________________ The above components are blended to form a homogeneous solution. The following components can be formulated in like manner. Ethanolammonium methallyl hexahydroazepinocarbonylphosphonate Dodecyltrimethylammonium butyl N-methylcarbamoylphosphonate Ammonium n-hexyl carbamoylphosphonate Six kilograms of the formulation of Example 86 are added to 400 liters of water containing 0.5% Tween 20 (Polyoxyethylenesorbitan monolaurate). This solution is sprayed to runoff on a freshly trimmed privet (Ligustrum ovalifolium) in May. The treatment greatly reduces the growth of the hedge. Little labor is required to keep it attractive all season. A solution containing 227 gms. of active ingredient formulated as above is sprayed on an area of red delicious apple trees about two weeks after petal fall. This treatment prevents the "June drop" and gives a higher yield of apples per acre than that from a similar untreated acre of trees. It also reduces the growth of spurious shoots known as "water sprouts" and ameliorates the tendency to biannual bearing which is strong in this variety. EXAMPLE 87 The following formulation is prepared. ______________________________________Ammonium methyl carbamoylphosphonate 25.0%Sodium lauryl sulfate 50.0%Magnesium silicate 10.0%Kaolinite 15.0%______________________________________ The above components are blended, micropulverized to pass a 0.30 mm. screen and reblended. The following compounds can be formulated in like manner. Morpholinium ethyl carbamoylphosphonate Sodium phenyl carbamoylphosphonate hemicalcium benzyl carbamoylphosphonate Five kilograms of the formulation of Example 87 are suspended in 100 liters of water and then sprayed to runoff on freshly trimmed trees and brush along the edge of a power line right-of-way. This treatment greatly reduces the growth of the trees and shrubs without permanent injury to them and they are prevented from growing over into the power line. The vegetation on the right-of-way is controlled by applying herbicides. This treatment reduces the labor required to maintain the line. EXAMPLE 88 An aqueous concentrate solution is prepared which contains the following ingredients: ______________________________________ammonium ethyl carbamoylphosphonate 24.0%N-dimethylaminosuccinamic acid 12.0%water 32.0%methanol 32.0%______________________________________ The above ingredients are stirred together with slight warming until a homogeneous solution results. A water solution of the formulation of Example 88 is prepared to contain 600 p.p.m. total active ingredient. This solution is sprayed on McIntosh apples to run-off in early September. The treatment prevents coloration in the apples and prevents premature fall before the apples are harvested. EXAMPLE 89 ______________________________________Ammonium ethyl carbamoylphosphonate 41.5%Water 58.5%______________________________________ The ingredients are combined and stirred to produce a solution containing approximately 4 pounds active ingredient per gallon (480 g. per liter). After filtration through a bed of diatomaceous earth, the product is packed in glass or plastic containers until use. In September, oaks (Quercus spp.), hickory (Carya spp.) and Loblolly pine (Pinus taeda) were treated with a foliar spray of the above formulation at the rate of 6 kg/ha in 800 liters of water. The treated plants showed no response that fall but next spring the deciduous species failed to develop new leaves and the pine did not develop new shoots. The treatment had prevented the new buds from breaking in the spring although plant stems and limbs were observed to be alive when examined closely. EXAMPLE 90 The following wettable powder is prepared: ______________________________________ammonium ethyl carbamoylphosphonate 30.0%maleic hydrazide 20.0%synthetic silica 2.5%montmorillonite 45.0%sodium alkylnaphthalene sulfonate 2.0%partially desulfonated sodium 0.5%lignin sulfonate______________________________________ The above ingredients are blended, micropulverized to a particle size essentially below 50 microns and reblended. The wettable powder of Example 90 is suspended in water at the rate of 4,000 p.p.m. of active ingredient and sprayed on an area of mixed brush under a power line. The application is made in mid-May just after the brush has been trimmed back to keep it away from under the power line. The solution is sprayed to run-off on the lower two-thirds of the trees which were not cut. This treatment effectively retards the growth of the trimmed vegetation for the next growing season as well as the one in which the vegetation is treated. The formulation of Example 90 is suspended in water at the rate of 1,000 p.p.m. of active ingredient and sprayed to the point of run-off on single trees located at random throughout orchards of apple, peach and cherry varieties. The treatments are applied while the trees are still in the dormant stage. During an early spring warm period the trees in these orchards begin to break dormancy and buds sprout. The treated trees, on the other hand, remain dormant and do not sprout nor flower while there is danger of frost. In this manner, a more reliable yield is assured. EXAMPLE 91 The following aerosol preparation is prepared: ______________________________________ ammonium ethyl carbamoylphosphonate 1.0% water 29.0% asphalt 20.0%B xylene 25.0% polyglycerol stearate 5.0%C [ dichloro difluoromethane 20.0%______________________________________ The predissolved aqueous phase (A), comprising active ingredient in water, is combined with the organic phase (B), comprising a solution of asphalt, emulsifier, and xylene, with agitation. To this is added, under pressure in an aerosol dispenser, the propellant C. Trees under a power line are trimmed back in early May to prevent them growing into the lines. The cut ends are treated with the wound dressing described above. The treatment reduces the break of lateral buds and retards the rate of growth of those that do break. In addition, the treatment causes overall retardation in the rate of growth of the treated plants. This lengthens the time between trimmings, reducing the cost of maintaining the power line. Trees treated include sweetgum (Liquidambar styraciflua L.), black willow (Salix nigra Marsh.), apple (Malus sp. Mill.), and red maple (Acer rubrum L.). EXAMPLE 92 The following asphalt emulsion is prepared: ______________________________________ammonium ethyl carbamoylphosphonate 4.0%sodium oleate 2.0%water 47.0%asphalt 47.0%______________________________________ The active compound, sodium oleate and water are combined and heated to 90° C. In a high shear mixer, molten asphalt is added. The suspension is cooled and packaged. This emulsion containing 4% ethyl carbamoylphosphonate is applied as a wound dressing in late Spring following conventional pruning on red maple (Acer rubrum L.), red oak (Quercus borealis Michx.), paper birch (Betula papyrifera Marsh.), and sugar maple (Acer saccharum Marsh.), growing under a power line. The treatment retards the breaking of lateral buds and the rate of growth of laterals. This reduces the future trmming necessary to maintain the area.

This disclosure teaches a method for employing novel carbamoylphosphonates such as ammonium ethyl carbamoylphosphonate, ammonium isopropyl carbamoylphosphonate and ammonium allyl carbamoylphosphonate to regulate the growth rate of plants. SP CROSS REFERENCE TO RELATED APPLICATIONS This application is a division of application Ser. No. 553,423, filed Feb. 26, 1975, now U.S. Pat. No. 3,997,544, which is a division of application Ser. No. 283,769, filed Aug. 25, 1972, now U.S. Pat. No. 3,846,512, which is a continuation-in-part of application Ser. No. 85,221, filed Oct. 29, 1970, now U.S. Pat. No. 3,819,353, which is a continuation-in-part of my application Ser. No. 803,962, filed Mar. 3, 1969, now abandoned, which was in turn a continuation-in-part of my earlier application Ser. No. 731,732, filed May 24, 1968, now U.S. Pat. No. 3,627,507.

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application Ser. No. 61/170,181, filed on Apr. 17, 2009, which is herein incorporated by reference in its entirety. FIELD OF THE INVENTION The present invention relates generally to battery systems and, more particularly, to an intelligent battery system for powering mobile workstations. BACKGROUND OF THE INVENTION Mobile computer workstations are desirable in numerous settings to make computer use more convenient and to make computers more accessible. For example, mobile workstations in the form of mobile medical carts are used in hospitals so that nurses and technicians may continually update patient information and treatment information from a variety of locations. In the hospital setting, for example, mobile workstations or mobile medical carts allow nurses to input changes in patient treatment or otherwise dispense patient care throughout the hospital environment while they are making their rounds. Powering such mobile workstations, however, has proven troublesome. As will be readily appreciated, it is undesirable to plug such workstations into a standard wall outlet, as power will be interrupted when moving from room to room or patient to patient. Battery powered systems have attempted to solve this problem, however, even known battery powered systems have objectionable shortcomings. For example, known battery-powered workstations provide a fixed battery system, mounted underneath the cart/workstation, having a single cell chemistry battery and charging technology. Such systems use a single battery and a “bucket” concept to swap out the single battery. These known batteries for powering mobile workstations, however, are difficult to replace when spent. Moreover, existing systems make it is necessary to interrupt power to the cart when changing such batteries, therefore interrupting work flow and potentially resulting in the loss of data. In view of the problems associated with known mobile workstations and systems for powering mobile workstations, there is a need for an improved battery system and, more particularly, for an intelligent battery system for powering mobile workstations wherein batteries may be swapped out without interrupting power to the workstation. SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide an intelligent battery system. It is another object of the present invention to provide an intelligent battery system for powering mobile workstations. It is another object of the present invention to provide an intelligent battery system for powering mobile workstations wherein spent batteries may be swapped out without interrupting power to the workstation. It is another object of the present invention to provide an intelligent battery system for powering mobile workstations that prevents batteries from being accidentally removed from the workstation. It is another object of the present invention to provide an intelligent battery system that is capable of maintaining power even if the main batteries are spent or accidentally removed from the workstation. It is another object of the present invention to provide an intelligent battery system that is capable of warning a user of the system of impending low battery capacity. It is yet another object of the present invention to provide an intelligent battery system that is capable of running multiple batteries in parallel to simultaneously power the workstation. It is another object of the present invention to provide an intelligent battery system that is capable of determining and displaying percent capacity and/or remaining run time of a battery or batteries. It is another object of the present invention to provide an intelligent battery system that regulates voltage output to the mobile workstation. It is another object of the present invention to provide an intelligent battery system and battery charger that can accommodate batteries with various cell chemistries. It is another object of the present invention to provide an intelligent battery system that has low voltage shutdown capability. It is another object of the present invention to provide an intelligent battery system and hot-swap device that can be retrofit on numerous existing medical cart applications. It is therefore a general object of the present invention to provide an intelligent battery system for powering mobile workstations, wherein batteries may be swapped out without interrupting power to the workstation, comprising two snap-on battery interface brackets for accommodating two hot-swap batteries, a main hot-swap battery and a secondary hot-swap battery, and a third snap-on bracket to hold a spare battery. The battery system further comprises an integrated circuit and microprocessor to regulate voltage output and for providing battery parameter information such as percent capacity and/or remaining run time. The spare battery includes an integrated circuit for detecting the removal of either or both hot-swap batteries, for detecting when either or both hot-swap batteries are low in capacity and for providing backup power. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below: FIG. 1 is a perspective view of an intelligent battery system and hot-swap device mounted on a medical workstation in accordance with one embodiment of the present invention; FIG. 2 is an enlarged perspective view of a hot-swap device without the batteries in accordance with one embodiment of the present invention; FIG. 3 is an enlarged perspective view of the hot-swap device of FIG. 2 with the batteries attached thereto in accordance with one embodiment of the present invention; FIG. 4 is an enlarged perspective view of a hot-swap device with alternative batteries attached thereto in accordance with another embodiment of the present invention; FIG. 5 is a perspective view of an intelligent battery system and the hot-swap device of FIG. 4 mounted on a medical workstation in accordance with another embodiment of the present invention; FIG. 6 is a perspective view of a charging station of an intelligent battery system showing the alternative batteries of FIG. 4 in accordance with one embodiment of the present invention; FIGS. 7 and 8 schematically illustrate an exemplary control circuit in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is directed to an intelligent battery system 8 for powering mobile workstations. More particularly, and as shown in FIG. 1 , the present invention is a multi-cell battery system that powers an in-hospital mobile medical cart workstation. The wireless workstation is typically utilized by nurses to dispense patient care throughout a hospital environment. Preferably the battery system may be used with NiMH, Li-Ion, NiCad, SLA and Li-Poly batteries, although batteries with any battery chemistry known in the art may be used with the present system. As best shown in FIG. 2 , the intelligent battery system of the present invention includes a “hot-swap” device 10 that is mounted to the side of a medical cart or other mobile workstation 12 . As used herein, “hot-swap” refers to a system/device that allows a user to swap batteries in or out of the device without interrupting power to the workstation. The device 10 includes two snap-on battery interface brackets 14 , 16 for releasably attaching two hot-swap batteries, a main hot-swap battery 18 and a secondary hot-swap battery 20 , and a third snap-on bracket 22 for releasably attaching a spare battery 24 in the event that one or both of the hot-swap batteries 18 , 20 are spent and need replacement. This configuration allows a user to perform a fresh battery change at the earliest convenience without interrupting power to the mobile workstation 12 and without having to immediately return to a designated battery charging station in some remote location. The battery interface brackets 14 , 18 , 22 are preferably of the Anton/Bauer Gold Mount® type, although any type of bracket assembly may be used. The Gold Mount® bracket is substantially rectangular in shape and is formed with a plurality of keyholes cut in a front surface thereof, each keyhole having an elongated ovoid or elliptical opening and a narrow depending slot. The keyholes include two upper slots and a centrally located lower slot disposed in a substantially triangular array for releasably attaching each battery. Formed between the two upper keyholes is a connector block having a pair of banana plug terminals for placing each battery in electrical communication with the system. The connector block and its operation are described in detail in U.S. Pat. Nos. 6,247,962 and 4,822,296, which are hereby incorporated by reference. In the preferred embodiment, the third snap-on spare battery bracket 22 is configured with an integrated circuit that enables the user to replace the spent hot-swap batteries 18 , 20 while the spare battery 24 and circuit automatically backs up the system. The spare battery circuitry is configured to detect the removal of either or both hot-swap batteries 18 , 20 from the snap-on interface brackets 14 and provide backup power during the exchange. The spare battery circuitry is also capable of detecting when either or both hot-swap batteries 18 , 20 are low in capacity and is configured to prompt the spare battery 24 to provide backup power when necessary. The two hot-swap batteries 18 , 20 are also configured with an Analog Fuel Gauge in electrical communication with the spare battery circuitry. The Analog Fuel Gauge reading emanating from the two hot-swap batteries 18 , 20 is utilized by the spare battery circuitry to determine low battery pack capacity and/or when one of the two battery packs 18 , 20 are removed from the system. The spare battery circuitry further has the ability to provide an alert to warn of impending low spare battery capacity. Preferably, the alert will be a visual alert in the form of a LED indicator, although other alerts such as audio alerts may also be incorporated into the hot-swap device 10 . The snap-on battery interface brackets 14 may also include a locking device 26 to prevent accidental removal of both batteries simultaneously, thus interrupting power to the workstation 12 . In yet another embodiment of the present invention, the hot-swap bracket contains an integrated circuit that is capable of combining the outputs of batteries 18 , 20 together, thus allowing both hot-swap batteries 18 , 20 to be used in either parallel or series, to power the workstation simultaneously. Fresh batteries may be swapped in or out without interrupting power to the workstation 12 . Preferably, the device further contains a software adjustable voltage regulator circuit, including either a linear regulator or DC/DC converter, that provides a predetermined optimal voltage output depending upon the specific requirements of a particular workstation and associated equipment. In the preferred embodiment, the voltage regulator circuit provides a maximum required 15.5Vdc. The regulator prevents over-voltage conditions due to hot-off-charge battery packs, i.e., battery packs that have just been charged and are at full charge. Without the regulator, hot-off-charge battery packs can reach upwards of 18Vdc open circuit and create operational problems for certain pieces of workstation or medical cart equipment. In another embodiment, the regulated output voltage can be adjusted to provide the voltage requirements for other workstations, medical carts, or other applications. Additionally, an inverter can be added to the device to provide 120/240VAC for AC operated medical carts or workstations. In the preferred embodiment, the device also contains a microprocessor control circuit that communicates with both hot-swap batteries 18 , 20 according to a particular protocol to monitor battery parameters. This communications protocol provides combined fuel gauging information in the form of percent capacity and/or remaining run time in hours and minutes for one or both batteries 18 , 20 . The device also contains an interface with a remote fuel gauge indicator to display percent capacity and/or remaining run time in hours and minutes to a user of the system. Moreover, the software may be modified to report percent capacity and remaining run time to other remote fuel gauges, and can communicate with existing fuel gauge systems. The battery system also includes a separate multi-station battery charger that can handle NiMH, Li-Ion, NiCad, SLA and Li-Poly, and other cell chemistries known in the art. In operation, a user can simply swap out the spent batteries at a designated charging station with fresh batteries from the multi-station charger. All batteries used with the present battery system contain smart battery fuel gauging circuitry that provides on-board LCD indicators of both percent capacity and remaining run time, i.e., real time information regarding battery capacity. Moreover, all batteries used with the present battery system contain a smart battery Analog Fuel Gauge (AFG) circuit that provides an on-board 0-5Vdc representation of percent capacity. The batteries used with the present intelligent battery system also contain competitor lock-out circuitry to prevent possible unsafe charging conditions resulting from differences in battery chemistries. Moreover, in the preferred embodiment, the batteries also contain over-current and thermal protection against end user abuse or workstation or medical cart equipment malfunction. Preferably, the batteries and integrated circuits of the intelligent battery system provide a low voltage shutdown capability to prevent the over discharge of battery packs, thereby eliminating unrecoverable battery failure due to cell reversal. Indeed, if it is detected that battery capacity has reached a predetermined/set lower limit, the batter may be automatically shut down to avoid battery failure. Turning now to FIGS. 7 and 8 , an exemplary control circuit capable of carrying out the advantages and features of the present invention, as discussed above, is shown. As will be readily appreciated by those of ordinary skill in the art, alterations in the configuration of the circuitry shown in FIGS. 7 and 8 are certainly possible without departing from the broader aspects of the present invention. Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of this disclosure.

An intelligent battery system for powering a mobile workstation includes a mounting block having a first battery interface bracket for the releasable attachment of a first battery, a second battery interface bracket for the releasable attachment of a second battery and a third battery interface bracket for the releasable attachment of a backup battery, and a power control circuit functionally integrated with the mounting block and being capable of detecting a change in status of at least one of the first and second batteries and routing the flow of electrical power from the first, second and backup batteries in dependence thereon.

BACKGROUND OF THE INVENTION The invention relates to a multi-function time delay relay with functions which can be changed from the outside. In a known multi-function time delay relay of the above-mentioned kind, a series of terminals are provided at the housing of the relay which make it possible, by changing jumpers or by rewiring the control lines to other terminals, to change the relay to four different functions: delayed make, delayed break, self-wiping make and cycling. This means that changes must be made at the terminals before the relay is placed into operation (Multi-function Relay TRZEU of the firm Metzenauer & Jung, Catalog Sheet W 2934/79). It is an object of the present invention to improve a multi-function time delay relay of the above-mentioned type in such a manner that it is possible to change the timing function in a simple manner from any point and at any time, i.e., even while the multi-function relay is running. SUMMARY OF THE INVENTION In a multi-function relay of the above-mentioned type this is achieved in a simple manner by implementing the delay function with an electronic timer which can be started, stopped and reset, preceded by a logic network with two inputs which, to obtain different modes of operation of the timer, can be supplied with voltage individually, separately and/or jointly at any desired point in time. It has been found to be advantageous if the timer is a programmable timing oscillator with a start (power-on) input, a output which changes the signal at the end of the cycle, a stop and resetting input as well as with an inverting input for the signal at the output. Such programmable timers are commercially available, for instance, from the firm Motorola under the designation MC 14541B. Their operation is described in the data sheets for the programmable timer MC 14541B, pages 9-538 to 9-543 published by Motorola. A particularly simple type of logic circuit for use with the timer is obtained by using a logic network which includes AND, OR and inverting stages and a flipflop. A simple design of the multi-function time delay relay with respect to circuitry is obtained if the voltage of the one input is applied to a first inverter, to the one input of each of two AND stages and the one input of a first OR stage. The voltage of the other input is fed to a second inverter stage, to the second input of the first AND stage and the first OR stage as well as to a first dynamic input of a flipflop. The output of the second inverter is connected to the second input of the second AND stage, the output of which is connected to the resetting input of the flipflop. The output of the first inverter is coupled to the first input of a third AND stage, the second input of which is connected to the second output of the flipflop. The output of the first AND stage is connected to the set input as well as to the second dynamic input of the flipflop and to the first input of a second OR stage, the output of which forms the control output of the time delay relay. The second input of the second OR stage is connected to the output of the programmable timing oscillator. The output of the third AND stage is connected to the inverting input of the programmable timing oscillator, the output of the first OR stage to the start input, and the first output of the flipflop to the stop and reset input of the programmable timing oscillator. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 7 show different level diagrams corresponding to the expected function of the time delay relay. FIGS. 8 to 10 illustrate specific applications of the time delay relay according to the present invention without auxiliary contacts. FIGS. 11 to 13 illustrate specific applications of the timing relay according to the present invention with auxiliary contacts. FIG. 14 shows a conventional application with auxiliary contacts and self-wiping make function. DETAILED DESCRIPTION The heart of the time delay relay according to the present invention is the timer, in the illustrated embodiment, the programmable timer 1. It has a start-up (power-on) input which is designated as U B and is also called Autoreset (AR). It is coupled to the supply voltage of the module. The running cycle is thereby started at T=0 as soon as a positive signal is supplied to the start-up input U B . The output Q of the oscillator changes its polarity at the end of the running cycle. The stop and reset input (MR), also called Master Reset, stops the cycle if a positive signal is present at this input. In addition, the counter is reset. The input designated Q S is an inverting input. During the running time, the output Q has, for instance, an L signal; after the end of the cycle is reached, the L signal changes to an H signal provided that a negative potential, i.e., L signal is present at the inverting input Q S . The output polarity is inverted whenever an H signal is present at the inverting input Q S . The network for addressing the programmable timing oscillator 1 consists, as shown in FIGS. 1 to 7, of two inverters I 1 and I 2 , three AND stages U 1 to U 3 , two OR stages O 1 and O 2 , and a flipflop FF. The flipflop has a first dynamic input C 1 which reacts to an edge rising toward H; a second input C 2 which reacts to an edge falling toward L; two oppositely polarized outputs Q 1 and Q 2 ; a set input S and a reset input R. The line voltage terminals are designated as A 1 and B 1 . The common other pole for the two voltages is designated as A 2 . The electrical combination of the individual AND, OR and inverter stages, and the flipflop with the programmable timing oscillator with each other can be seen from FIGS. 1 to 7 without further explanation. The level diagrams of FIGS. 1-7 show the signals at individual points depending on the manner of operation. FIG. 1 shows the level plan for pick-up delay. Here, voltage is applied to A 1 during the running time. The output Q of the timer 1 and the control output St are inactive. However, an H signal is present at the start input U B , so that the output signal changes when the end of the cycle is reached; the time delay relay switches with a delayed pickup as can be seen from the level plan of FIG. 2. There, voltage continues to be present at A 1 , and an H signal at the output Q and at the control output St, so that the switching member of the time delay relay itself, not shown here, can be activated thereby. FIGS. 3 to 6 represent the drop back delay. In FIG. 3, voltage is applied to B 1 . The output Q 1 of the flipflop FF is set by C 1 and blocks the timing oscillator via the stop and reset input MR. The control output St as well as the output Q of the timing oscillator 1 carry an L signal. If A 1 is not added on, see FIG. 4, the timing cycle, i.e., the output Q of the timing oscillator, remains blocked; the control output St becomes active via the AND gate U 1 and the OR gate O 2 2 , i.e., the time delay relay is switched. This case would correspond to the so-called immediate switching mode during the function "drop-out delay." If the voltage is now removed again from A 1 and voltage remains at B 1 , the outputs Q 1 and Q 2 of the flipflop FF are inverted by C 2 . The stop and reset input MR releases the timing oscillator 1 and the timing cycle runs. The control output remains active via the AND gate U 3 , the inverting input Q 2 , the output Q of the timing oscillator and the OR stage 2, see FIG. 5. When the return time is reached, the output Q of the timing oscillator 1 goes to an L signal; the control output is thereby made inactive and the time delay relay is switched off. This can be seen from the levels in FIG. 5. Simultaneous inversion of the inputs A 1 and B 1 would be an unintended control process which, however, can occur accidentally. A 1 changes from zero to the nominal voltage and B 1 , from the nominal voltage to zero. This corresponds to the start of the response delay, as can be seen from FIG. 1. If A 1 changes from the line voltage to zero and B 1 from zero to line voltage, the dynamic inputs C 1 and C 2 of the flipflop FF are addressed simultaneously by the proper edges. This case can be seen in FIG. 7. Depending on whether simultaneity is briefly interrupting or briefly overlapping, either the case "auxiliary voltage addition" according to FIG. 3 or the case "start drop-back delay" according to FIG. 5 will occur. In inverting, care must therefore be taken that an unambiguous pause or an unambiguous overlap is provided. The specified pick-up delay or drop-back delay can be realized with a relay circuit as shown in FIGS. 8 and 9. In the case of pick-up delay, only the control contacts of FIG. 8 must be closed, i.e., the auxiliary switch SH can be omitted since voltage must be applied only to A 1 . In the case of a drop-out delay as shown in FIG. 9, voltage is also continuously applied to B 1 , i.e. the auxiliary switch SH is closed and the control contacts S merely connect A 1 to the line. FIG. 10 shows a possible circuit for immediate switching or connecting through. As soon as voltage is applied to A 1 and B 1 , simultaneously or in any sequence shifted in time, the output Q of the flipflop FF is set via the AND gate U 1 , which blocks the timing oscillator. At the same time, the control output becomes active via U 1 and the OR gate O 2 . The relay pulls up or remains pulled up, (see the level plan of FIG. 4). The following cases can be distinguished here: If voltage is applied simultaneously to A 1 and B 1 , i.e., the switch SH of FIG. 10, is closed, and the control contact S is actuated later, the relay switch is switched immediately. If B 1 is switched on to A 1 after the end of the cycle, i.e., if SH is closed after S, the relay remains energized. If B 1 is added to A 1 during the running time, the running cycle is shortened. If on the other hand A 1 is added to B 1 after the return time (which is not possible with the circuit arrangement according to FIG. 10), the relay is switched on. If A 1 is switched on in addition to B 1 during the running time, the return time is broken off. If A 1 and B 1 are without voltage, the relay drops off and the timing oscillator stops. Here also, the following possibilities can be distinguished again: No voltage at B 1 and after the end of the cycle, the voltage is removed from A 1 , i.e., the relay drops off. B 1 again has no voltage and the voltage is removed from A 1 during the running time, i.e., the cycle is broken off. If however, A 1 has no voltage and the voltage is removed from B 1 after the return time, the relay remains dropped off. If A 1 has no voltage and the voltage is removed from B 1 during the return time, the return time is shortened. It can be said in summary that, regardless in what state the relay operates, during the running time or after the end of the cycle, and independently of whether the relay operates with a response delay or with a delayed drop-out: if A 1 and B 1 are energized, the relay is switched on and the running cycle stops and, if A 1 and B 1 are de-energized, the relay is switched off and the running time is reset. As has been demonstrated, the timing function can be changed by appropriate addressing regardless of the function phase then running. Thereby, timing functions such as make or break wiping, blinking and pick-up and drop-out delay can be realized in addition to pick-up delay, drop-out delay and immediate switching. Break wiping is shown by way of example in FIG. 11. The auxiliary switch SH is closed and the control contact S is connected in the circuit B 1 , i.e., A 1 and B 1 carry voltage. The break contact of the relay is open, because the switching state according to FIG. 4 is present. If B 1 is de-energized, this corresponds to the level plan of FIG. 1, i.e., delayed pick-up; the relay drops off and pulls up again after the end of the cycle. The break contact acts like a break wiper. FIG. 12 shows pick-up and drop-back delay. If the make contact of the relay is used to connect the control input B 1 to the control voltage (this also can be accomplished via an auxiliary switch SH), the timing function "pick-up and drop-back delay" is obtained, as can be seen from the FIGS. 1, 4 and 5. The make contact is not without potential, however. By including an auxiliary relay R, the timing function "blinking" can be realized as indicated in FIG. 13. The operation is in principle similar to pick-up and drop-back delay except that the return time follows the running time immediately. The auxiliary contact r of the auxiliary relay R controls the blinking cycle automatically. FIG. 14 merely shows that the function "make wiping" can also be carried out with the relay according to the present invention without difficulties, as with conventional response delay relays. The explanations above show that it is possible with the time delay relay according to the present invention to realize, merely by addressing two control inputs, the most important timing functions described above at any time and in any sequence, i.e., even during a running cycle and with remote control. It is possible with the time delay relay according to the present invention to automatically switch timing functions without causing illogical reactions. The timing functions are switched automatically at installations: normal (without auxiliary voltage)=pick-up delayed and with auxiliary voltage=drop-out delayed. Additional adjusting means such as switches, plugs or terminals are unnecessary. The large number of attainable functions is listed in principle in the following function table. The arrow shown there next to the voltage U is to indicate either the addition or removal of the voltage. The central part of the table under "Comments" indicates which function phase is present, and under "level diagram" a reference is made to the corresponding figure, if shown. ______________________________________ LevelA.sub.1 B.sub.1 Comments Diag.______________________________________Pickup U↑ O Start, pick-up delay (AV) FIG. 1Delay U O during the running time (AV) FIG. 1 U O after end of cycle FIG. 2Drop-out O U↑ Addition of auxiliary voltage FIG. 3Delay U↑ U Excitation of drop-back delay FIG. 4 U↓ U Start drop-back delay FIG. 5 O U during the running time (RV) FIG. 5 O U after the return time FIG. 6Immediate U↑ U↑ Immediate switching FIG. 4Switching U U↑ after the end of cycle FIG. 4 U U↑ during the running time (AV) FIG. 4 U↑ U after the return time (Av) FIG. 4 U↑ U during the running time (RV) FIG. 4Immediate U↓ O after end of cycle,-Drop-out U↓ O during the running time (AV),- O U↓ after the return time,- O U↓ during the running time (RV),-Other U U↓ Start, make wiping FIG. 1 U↑ U↓ Start, pick-up delay FIG. 1 U↓ U↑ indifferent, leads to addition FIG. 7 of auxiliary voltage or start, FIG. 3 drop-back delay. FIG. 5______________________________________

A multi-function time delay relay, with functions which can be changed from the outside, includes a timing oscillator and a logic network consisting of AND and OR stages and inverter stages as well as a flipflop interconnected in such a manner that two voltage inputs applied individually, separately or jointly, can bring about different modes of operation of the timing oscillator making it possible to realize different timing functions at any time and in any sequence, even during a running cycle, without having to intervene at the relay itself.

TECHNICAL FIELD This invention relates to reciprocating piston machines, such as internal combustion engines, and to crankshafts for such machines, engines and the like. In a preferred embodiment, the invention relates to multiple throw crankshafts for engines and in combination therewith. BACKGROUND In U.S. Pat. No. 2,103,185 Rumpler, issued Dec. 21, 1937, it is proposed to form a hollow engine crankshaft with progressively increasing wall thickness toward the output end in order to accommodate the accumulative gas forces transmitted by the journals, crankpins and crankarms as the output end is approached. While such a crankshaft design may be appropriate for some engine configurations, the patent's teachings apparently fail to consider that a crankshaft has finite stiffness and will have resonant frequencies excited by the firing loads and/or the engine speed. The absence of concern for torsional vibration in Rumpler's patent is a reflection of the typically lower maximum speed of engines in 1937. The loads caused by torsional vibration of todays high speed engines, commonly operating in the neighborhood of 7-8,000 RPM, must be accounted for in the design in addition to the gas forces. SUMMARY OF THE INVENTION The present invention provides an improved crankshaft construction which, in combination with its connected components, approaches, more closely than conventional designs, a maximum torsional frequency with minimum vibration amplitudes and torsional stress under its design operating conditions. To provide a finished crankshaft design according to the invention requires analysis of the crankshaft system in accordance with known methods of vibration analysis. This analysis is based on the torsional stiffness and inertia characteristics of the entire crankshaft. This information is used in combination with the operating load data (i.e., engine RPM and cylinder pressure data) to determine the vibratory response of the system. The critical pieces of information determined in this analysis are the resonant frequencies, amplitudes of vibration, and the torsional stresses. The torsional stiffness and mass/inertia of the crankarms are varied above the minimum values required for delivering the maximum driving torques applied to the crankarms during operation. The intent is to provide a maximum stiffness near the nodal point of the first resonant mode of the crankshaft system (the nodal point is the position of zero torsional deflection) and then reduce the stiffness and inertia/mass of the other crankarms in relation to their distance from the nodal point. In this manner, inertia torques are minimized and therefore vibration amplitudes and stresses are minimized while increasing the resonant frequencies as compared to conventional designs in which the crankarms all have equal torsional stiffness and inertia/mass. In a practical application of the invention, it may be desirable, for design and manufacturing simplification, to approximate the ideal design by limiting the differences in the crankarms. Thus, it is possible, for example, to make of equal size and torsional strength, pairs of crankarms on either side of each main journal, or both crankarms of each crankthrow, while varying the torsional strengths of the pairs of crankarms generally in proportion to their distances from the vibration node, or nodal point. These and other features, modifications and advantages of the invention will be more fully understood from the following description of a preferred embodiment, taken together with the accompanying drawings. BRIEF DRAWING DESCRIPTION In the drawings: FIG. 1 is a cross-sectional view of an internal combustion engine having a low resonance crankshaft formed in accordance with the invention; FIG. 2 is a side view of the crankshaft having superimposed thereon a mode shape diagram of the crankshaft torsional vibration amplitudes as connected in the engine assembly and operated at a maximum torsional vibration operating condition; and FIGS. 3-10 are transverse cross-sectional views through the crankshaft at the locations indicated by the lines 3--3 to 10--10 respectively of FIG. 2 and showing the configurations of the various crankarms. DETAILED DESCRIPTION Referring now to the drawings in detail, numeral 10 generally indicates a four-stroke cycle four cylinder automotive-type internal combustion engine intended for use in automobiles or the like. Engine 10 includes the usual engine cylinder block 11 having a plurality of cylinders 12 aligned in a single bank and closed at their ends by a cylinder head 14. The block 11 also defines a crankcase having an open bottom that is conventionally closed by an oil pan 15. Rotatably carried in the crankcase portion of the engine block 11 is a crankshaft 16 formed in accordance with the invention. The crankshaft includes five main journals 18-22 supported in axially spaced and aligned main bearing webs 24 of the engine block. Between the adjacent pairs of journals are radially offset crankpins 25-28, each supported by a pair of crankarms. From front to rear the crankarms are indicated by numerals 31-38. In addition, the crankshaft includes a front end stub 42 and a rear end flange 43. As is conventional, the crankpins 25-28 connect through connecting rods 44 with pistons 46 reciprocably movable in the cylinders 12. In assembly in the engine, a flywheel 47 is attached to the flange 43 at the rear of the crankshaft for connection with a clutch, the torque converter of an automatic transmission or other associated output means. At the front end, an oil pump drive gear 48 and a camshaft and accessory drive 50 are mounted on the stub 42. In order to minimize the torsional vibration stress and deflection that occur in the crankshaft during engine operation, the invention provides for the selective sizing of the individual crankarms to obtain the minimum mass and optimum stiffness needed to withstand the combination of torsional vibration and other forces that occur at their respective locations. The design process first requires selection of the major crankshaft characteristics, including main and crankpin dimensions and spacing and the selection of nominal crankarm dimensions to provide a first approximation of a crankshaft design adequate to withstand the calculated driving torque pulses. There follows a torsional vibration analysis of the crankshaft as assembled with its associated pistons, accessory drive, flywheel and other components that are to be fixedly attached to or driven by the crankshaft. The analysis determines the vibration node or zero point of angular deflection in the system in the torsional vibration mode or modes of interest in the engine operating speed range. The angular deflection is then reduced by substantially stiffening the crankarms near the node while increasing less, or even reducing, the stiffness (and mass) of the other crankarms in approximate proportion to their distances from the node. This requires an iterative process of adjusting the stiffness and inertia/mass of the crankarms and then recalculating the torsional vibration characteristics until an overall maximum torsional natural frequency, giving a minimum angular deflection of the crankshaft, is reached, or is approached to a degree considered satisfactory to the crankshaft designer. This process requires recognition that, as the axial distance from the node increases, the crankarms will generate increasing inertia torques. Therefor, it is desirable to make the crankarms near the node as stiff as possible to minimize the angular deflection which occurs there. On the other hand, substantial reductions in the inertia/mass of the crankarms at the greatest distances from the node, or nodal point, will result in the most significant reductions in the maximum angular deflection. This effect may more than offset the resulting reductions in stiffness of the distal crankarms, although, of necessity, they must remain sufficiently stiff to accept the maximum torque loadings imposed on them by the pistons in the normal operation of the engine. The results of applying the described method to the crankshaft 16 described herein are seen in the side view and mode shape diagram of FIG. 2 and the cross-sectional views of FIGS. 3-10, in which the background throws have been omitted for clarity. In FIG. 2, the mode shape diagram indicates, by the distance from the crankshaft axis 51 of a dashed line 52, the relative angular deflection, in degrees double amplitude (DDA), of the adjacent crankshaft portions (in the same normal plane) at the resonant operating speed. The node 54, or nodal point, is where the line 52 crosses the axis 51, indicating that the angular deflection is zero at that point. In the crankshaft development, design and manufacturing simplicity were served by utilizing identical crankarm configurations for the pairs of crankarms on either side of the interior main journals 19-21. Thus, FIGS. 3 and 4, showing the configurations of crankarms 32 and 33, respectively, on opposite sides of main journal 19, indicate identical crankarm shapes of relatively narrow width (i.e. laterally in a plane normal to the axis 51), giving relatively low inertia/mass (and stiffness in view of their location at a relatively great distance from the node 54. FIG. 5 shows the front crankarm 31, at the furthest distance from the node 54, also has the narrowest width and the lowest inertia/mass and stiffness of all the crankarms. At this location, a crankshaft counterweight 55 is also located, extending oppositely from the crankarm 31. FIGS. 6 and 7 illustrate the crankarms 34, 35 and associated counterweights 56, 57 disposed on opposite sides of the center main journal 20. The crankarms of this pair are of substantially greater width, mass and stiffness in view of their closer location to the node 54 than narrow crankarms 32, 33. FIGS. 8 and 9 illustrate the pair of crankarms 36, 37 disposed on either side of main journal 21. Both of these crankarms are of near maximum stiffness as indicated by their greater width, since their locations are at or near the node 54. However, the shape of crankarm 36 differs further since it also incorporates a reluctor ring 58 for use as a timing wheel during engine operation. In view of the extra mass added to the crankshaft by this ring, it is desirably located at a point as near to the node as practical, hence the incorporation into crankarm 36. It should be apparent that crankarm 37 would be an even better location, if permitted by other features of the engine. FIG. 10 shows the configuration of the rear end crankarm 38 together with the associated rear counterweight 59. By virtue of its position very near to the node 54, crankarm 38 is of a relatively great width, mass and stiffness similar to that of the crankarm 36. In the crankshaft embodiment shown, it is apparent that the masses and stiffnesses of the various crankarms have been varied primarily by varying their lateral widths. However, it should be understood that other forms of construction, such as variations in longitudinal thickness or hollowed portions, could be utilized for varying the masses and stiffnesses of the crankarms without departing from the scope of the invention. Thus, while the invention has been described by reference to one illustrated embodiment, it should be understood that numerous changes could be made within the spirit and scope of the inventive concepts described. Accordingly it is intended that the invention not be limited to the illustrated embodiment, but that it have the full scope permitted by the language of the following claims.

A low vibration crankshaft has crankarms of decreasing inertia/mass and stiffness as their distance torsional vibration node of the rotating vibration system increases. The mass and stiffness of the crankarms may be varied by changing the lateral width of the arms or by other means. The arrangement provides, in combination with an engine or other reciprocating piston machine, an increased or maximized torsional vibration resonant frequency and resulting lower or minimized angular deflections of the crankshaft in the condition of system resonance.