bluuebunny/crossref_metadata_2025_split huggingface dataset:
AN IMPROVED FORM OF ELECTROCARDIOGRAPH
Authors: Caldwell S. H. , Oler C. B. , Peters J. C. 
Published: February 2005

An electrocardiograph is described which has been designed to secure a more nearly uniform response characteristic, as a function of frequency, over the desired frequency range, than is obtainable with the Einthoven string galvanometer ordinarily used for this work. It is shown by harmonic analysis that relatively high frequency components are present to a large degree in the ordinary electrocardiogram, and due to their magnitudes, have a large influence on the shape of the wave.
More accurate interpretation of the electrocardiograph record is desirable, and is made possible by using an amplifier in conjunction with a standard type of oscillograph to produce a larger record, without reducing the accuracy at higher frequencies. The vacuum tube amplifier was specifically designed for the purpose. It has a high input impedance so that the effect of body resistance is negligible. A standardizing circuit is built into the amplifier so that calibrations can be obtained readily.
The tests on this apparatus were carried out both at the Massachusetts Institute of Technology and at the Evans Memorial of Boston. Illustrations from these tests are included, showing comparisons between records obtained from a standard type of string galvanometer electrocardiograph and from the new apparatus.
A Direct-Reading Rate Meter for High-Intensity Penetrating Radiation
Authors: Morgan J. E. , Chambers F. W. , O'Connor D. T. , Istock J. T. 
Published: February 2005

Inherent technical difficulties in the measurement of x-ray intensities from 100 to 5000 r/minute, at exciting potentials between 400 and 2000 KVP (kilovolts peak), have been investigated.
Extending the ranges of conventional condenser-electrometer dose meters by use of absorbing media not only increases energy dependence, but is also found to cause an apparent displacement in effective geometrical location of the ionization chamber. 250-r, 1000-r and 2500-r condenser chambers have proved susceptible to serious errors from dielectric leakage, which increase rapidly with chamber range above 100 r and with radiation energy above 200 KVP. Associated measurements of voltage saturation indicate that no error from this source need be expected for full-scale exposure times exceeding two seconds.
A direct reading circuit has been developed to combine the known wavelength characteristics of ``air wall'' thimble-type chambers with the linear current response of a portable d'Arsonval galvanometer. A 25-r Victoreen chamber, remotely read through lengths up to 70 feet of polyethylene coaxial cable, shows linear calibration from 35 to 5500 r/minute with over-all reproducibility to the order of ±1.5 percent. Ionization readings correspond, within the accuracy of chamber volume determination, to the definitive value of esu/cc second.
Low-Temperature X-Ray Goniometer for Structural Studies of Crystal Transitions
Authors: Keeling R. , Frazer B. C. , Pepinsky R. 
Published: February 2005

A low-temperature x-ray goniometer for use between liquid nitrogen temperature and approximately −100°C has been designed for use with a Weissenberg camera, General Electric powder camera, or a Geiger counter system. The crystal is mounted on a goniometer head inside a vertical cylindrical stainless-steel Dewar, and is irradiated through a polystyrene tip at the lower end of the Dewar. The crystal is cooled by conduction through the goniometer head, which is silver-soldered to the base of a liquid nitrogen chamber inside and concentric with the outer wall of the Dewar. The Dewar vacuum is maintained by an oil diffusion pump and a forepump, through a rotating seal and the post which supports the goniometer.
The Weissenberg camera mounts on a carriage and is driven by a 60-rpm reversing motor which also rotates the Dewar and crystal.
The carriage driving screws may be uncoupled from the motor shaft, and a Geiger counter spectrometer may be mounted on the carriage in place of the camera. The carriage is also adaptable for holding a G.E. powder camera.
A General Electric CA-7 x-ray tube mounted horizontally supplies the x-ray beam.
A Thermal Gradient Method for the Study of Crystal Structure and Its Application to Order-Disorder Research
Authors: Newkirk John B. 
Published: February 2005

A new method has been developed for studying the effect of temperature on the crystal structure of metals and alloys. In this method, a long wire specimen is held for a desired period of time in a known thermal gradient and is subsequently quenched and examined at room temperature by x-ray diffraction. A special x-ray camera is used, by means of which any point along the length of the specimen can be irradiated. The diffracted rays are registered on a cylindrical film in the usual way. This technique offers substantial savings in treating time and has the advantage of subjecting the specimen to all temperatures within the range of treatment.
The method has been applied to the study of ordering phenomena in several binary systems. Debye-Scherrer evidence for the existence of divariant equilibrium between ordered and disordered phases, has been found in several alloys of nonstoichiometric composition. A study of the copper-gold system has yielded data which allow the quantitative location of the (order+disorder) field boundaries near CuAu.
Improvements in Design and Construction of Quartz Helix Balances
Authors: Ernsberger F. M. , Drew C. M. 
Published: February 2005

The methods previously used for drawing quartz fiber and winding the fiber into helical springs may be considerably simplified by using a machinist's lathe for both operations. This makes available all the necessary mechanical motions, without constructing special units for the purpose. Fiber may be drawn uniformly to any predetermined diameter between 1.6 and 10 mils and wound with any desired coil diameter and pitch.
In the section on helix design, the performance of a helical balance is analyzed quantitatively in terms of its sensitivity, load capacity, and loaded length. It is shown that an optimum relationship exists between these characteristics, and a method is developed for specifying the dimensions of the helical balance which will give optimum performance in a given application.
The Cockcroft-Walton Voltage Multiplying Circuit
Authors: Everhart Edgar , Lorrain Paul 
Published: February 2005

The conventional Cockcroft-Walton voltage multiplying circuit is studied considering it as a transmission line. It is shown that, even when no direct current is drawn from the high voltage electrode, there is an important loss in output voltage caused by circulating currents in the stray capacitances. This loss of voltage is independent of the supply frequency. Formulas are developed for the voltage efficiency resulting from a given choice of capacitor size and number of stages.
Two modifications of the Cockcroft-Walton circuit which improve the voltage efficiency are suggested and analyzed. The first of these involves a loading coil at the high voltage end of the line. The second involves the addition of inductors in series with each of the capacitors of the circuit.
The Theory of the Fixed Frequency Cyclotron
Authors: Cohen Bernard L. 
Published: February 2005

The theory of the fixed frequency cyclotron is developed and illustrated at each step with numerical results for an example. The conditions for ion transmission with respect to horizontal motion are derived, and it is shown that they are satisfied by all ions in most cyclotrons. A more correct and more complete focusing formula than that found in the literature is derived and used to integrate the vertical motion. It is characterized by a region in which the net force is defocusing causing the ions to diverge exponentially from the median plane.
The theory is applied to find the maximum energy attainable as a function of dee voltage and magnetic field fall-off. The problem of orbital precession is treated quite generally, and equations for calculating the center of curvature as a function of time are derived. Some considerations in the magnetic field design are presented. A proof is given that ions experience strong radial grouping. The effect of ion source ``feelers'' is discussed.
A Fast Neutron Coincidence Spectrometer
Authors: Chagnon Paul R. , Madansky Leon , Owen George E. 
Published: February 2005

A fast neutron coincidence spectrometer of high efficiency has been constructed applicable to the approximate energy range of 1 Mev to 20 Mev. Design considerations and the working model are discussed.
To illustrate the operation of such an instrument, the line spectra of the gamma-rays from Co60 and of 3.3- Mev D-D Neutrons are presented. Discrimination between gamma-rays and neutrons is obtained by utilizing the difference in the time of flight of the two particles. In conclusion possible improvements are suggested.
Construction of a Universal Electron Diffraction Microscope and its Optical Features
Authors: Tanaka Kenzo , Hashimoto Hatsujiro 
Published: February 2005

A universal electron diffraction microscope, as we call it, consists of three stage electron lens and two specimen chambers and functions both as an electron microscope and as an electron diffraction unit. This instrument can be used in the following seven ways:
(1) Electron microscope; range of magnification between 800 and 20 000 times can be covered continuously.
(2) Electron microdiffraction unit; electron diffraction pattern characteristic of any small area of a specimen under microscopic observation can be revealed by a switch.
(3) Dark-field electron microscopic image.
(4) High-resolution electron diffraction unit.
(5) Effective camera length of electron diffraction is variable from 0 to 250 cm.
(6) Shadow micrographs of the specimen used in (4) can be directly obtained.
(7) Shadow microdiffraction (probe diffraction); dark-field microscopic image appears in each diffraction spot.
The specimen in the second chamber can be heated at any temperature up to about 800°C and on which two kinds of substances can be evaporated, and this evaporation gun can also be used for charge neutralization.
A Forward Angle Light Scattering Camera for Determining Size Distribution in Aerosols
Authors: Lee Pui-Kum , La Mer Victor K. 
Published: February 2005

The light scattered in the near forward direction from individual dioctyl phthalate (DOP) droplets flowing in a thin stream of known thickness and illuminated by a high intensity electronic flash tube is recorded photographically for the determination of number concentration and size-frequency distribution. The photos are taken slightly off-focus so that the pin-point images at focus are expanded into diffraction patterns. The optical density of each pattern is used as a measure of its droplet size.
The correlation between optical density and droplet size was determined with a series of aerosol preparations of known size and of size distribution characterized by a standard deviation which is about 10 percent of the mean. This correlation permits the translation of the measured frequency curve for optical density into a size-frequency distribution. The method has been checked by determining the size-frequency distribution of synthetic mixtures of known size. The reliable range of measurement extends from 0.12 to 0.50 μ radius.
Achromatic Beam Translation Systems for Use with the Linear Accelerator
Authors: Panofsky Wolfgang K. H. , McIntyre J. A. 
Published: February 2005

The beam of a linear accelerator has desirable properties regarding its geometry but frequently contains secondaries produced in the machine and has an unsuitable energy spectrum.
Two systems have been designed which translate the accelerator beam without energy dispersion. In the one system, now in operation, the emergent beam has an ``energy focus,'' i.e., a point at which the initial beam geometry is reproduced independent of energy. The second system is designed to produce a beam translated but otherwise unmodified in geometry, independent of beam energy to the first order.
Both systems permit easy control of energy width and produce a beam free from secondaries.
A Device for Determining Relative Stopping Powers for Natural Alpha Particles
Authors: Ellis R. Hobart 
Published: February 2005

A device is described by which the stopping power for polonium alpha particles of thin solid or liquid films can be compared with that of gases. An optical system measures film thickness, and the relative stopping power is inferred from the decrease of range which results when a thin film is inserted across a beam of alpha particles.
The device has been used with polystyrene and acetylene and a relative stopping power of 0.99±0.02 is observed.
Techniques for Processing Thick Nuclear Emulsions
Authors: Stiller Bertram , Shapiro Maurice M. , O'Dell Francis W. 
Published: February 2005

Techniques are described for the ``eradication'' and processing of thick electron-sensitive nuclear emulsions, and for handling ``pellicles.'' 400-micron and 600-micron emulsions, eradicated by a method which preserves their sensitivity to minimum-ionization particles, exhibit marked reduction in track distortion, as well as in background. A modified procedure for uniform development of thick emulsions by the temperature-cycling method gives a favorable ratio of grain density to background. Countermeasures against stripping of thick emulsions from their glass base have proved efficacious over a 3-year period.
A stack of emulsions without glass support (``pellicles'') provides a large sensitive volume in which tracks can be readily followed from one layer to the next. The lateral swelling (∼25 percent) during processing, which discouraged the application of this technique, was overcome by the authors [Phys. Rev. 85, 712 (1952)] in 1951. They evolved a successful method for mounting thick, stripped emulsions onto glass after exposure, but prior to processing, so that the pellicles can be developed as ordinary plates. Since then, additional experience has been gained in the application of pellicle stacks to high-energy physics. Our procedures lead to emulsions free from lateral swelling, free from blistering, and characterized by a level of distortion sufficiently low to permit multiple scattering measurement even on fairly ``stiff'' tracks. The advantages and limitations of this technique, its possible applications, details of the mounting procedure, and methods of following tracks from layer to layer are discussed.
Vortex Burner—A Useful Tool for Studying the Flame Stability of Gaseous Fuels and Fuel Mixtures
Authors: Kurz Philip F. 
Published: February 2005

A vortex burner has been developed that permits direct comparison of flame stability of fast-burning and of slow-burning gaseous fuels and their mixtures.
In this burner, air is introduced tangentially into a chamber to generate a vortex. The vortex is then accelerated by means of a converging nozzle which directs the air into a throat section where fuel is injected radially from ports in the periphery of the throat. The flame is stabilized in space in a divergent, pressure-recovery section and burns as a whirling inverted cone.
Flame stability is independent of tangential velocity at any given air rate. However, changes in other parameters, such as throat diameter and length of the pressure-recovery section, do have an effect on flame stability.
The results of these investigations with the vortex burner suggest that further studies with longer recovery sections are of interest. Likewise, the effect of gas temperature on flame stability will be studied.
The Production of 320-Mev Deuterons by He3 Stripping
Authors: Ise John , Pyle Robert V. , Hicks Donald A. , Main Robert M. 
Published: February 2005

Deuterons can be accelerated in the 184-in. cyclotron to 190 Mev. To produce higher-energy deuterons, doubly charged He3 ions are accelerated to 493 Mev, and a fraction of them are stripped in an internal target, yielding deuterons with an average energy of 330 Mev. A current of 5×10−13 ampere is obtained in the experimental ``cave'' external to the cyclotron shielding. Range measurements indicate that these deuterons have an average energy of about 320 Mev.
The high cost of He3 necessitates an efficient gas-recovery system. The exhaust from the cyclotron diffusion pump is passed through activated charcoal traps which are cooled to liquid-nitrogen temperatures, and the gas that is not adsorbed (presumably helium) is returned to the cyclotron source. The loss from all causes is 0.8 cc/hour.
The University of Washington Sixty-Inch Cyclotron
Authors: Schmidt F. H. , Farwell G. W. , Henderson J. E. , Morgan T. J. , Streib J. F. 
Published: February 2005

The new constant frequency 60-inch cyclotron at the University of Washington is described. Its principle mechanical features are the following: (1) A 20-inch diffusion pump is placed close to the vacuum chamber in order to provide high pumping speed; (2) The rf conductors are almost free of unsoldered joints in order to provide a high ``Q'' circuit; (3) The positions of the shorting ``spiders'' can be readily changed without breaking the vacuum; (4) The dees and dee stems are removable as one unit from the vacuum envelope; (5) The cyclotron vacuum chamber is constructed of welded aluminum alloy in order to reduce accumulated radioactivity; (6) A unique side-loading target chamber can be used for ordinary bombardments without disturbing apparatus more remote from the cyclotron; (7) The exit strip and other parts of the dee system subject to beam erosion are made of graphite.
The oscillator uses a single ML-5681 tube in a grounded-grid self-excited circuit. A 2-kw frequency-modulated booster oscillator drives the main oscillator above the ``multipactoring'' threshold. A cathode bias resistor is used in place of the familiar constant-current network. Ions are drawn out of the dees by means of a dc-biased rf deflector. Four degrees of freedom of the deflector are adjustable from the console.
An account is given of the major troubles encountered and the steps taken to achieve satisfactory operation. The cyclotron produces external beams of 125 to 200 μa at a nominal deuteron energy of 21 Mev with an oscillator power input of 100–125 kw.
An Electric Field Meter with Extended Frequency Range
Authors: Smith L. G. 
Published: February 2005

The frequency range of a field meter of the field mill type has been extended by applying a system of balanced modulation. This is achieved by incorporating two complementary sets of stators. The amplified signals from the stators are detected in a clamping circuit. In the instrument which is described, the frequency range extends to 22 kcps although the modulation frequency is 120 cps.
The method by which the frequency range has been extended can be adapted to other instruments employing mechanical modulation.
The Radio-Frequency Fine Structure of the Photon Beam from the Berkeley Synchrotron
Authors: Madey Richard , Bandtel Kenneth C. , Frank Wilson J. 
Published: February 2005

The full energy spread-out bremsstrahlung beam of the Berkeley synchrotron was shown to be emitted in sharp bursts with the 47.7-Mc/sec frequency of the electrons in the doughnut. A two-counter telescope, located about 20 inches away from a one-fourth inch thick lead target and about 20 degrees from the photon beam direction, was used to measure an accidental coincidence counting rate as a function of the length of delay line in one input to the coincidence circuit. When the length of delay cable was chosen equal to integral multiples of the period of the radio-frequency oscillator, the coincidence counting rate was of the order of 100 counts per unit of integrated beam; on the other hand, when the length of delay line was chosen to be equal to one-half of odd integral multiples of the period of the radio-frequency oscillator, the coincidence counting rate was less than about two counts per unit of integrated beam.
An estimate of the width of a single pulse of photons can be obtained from the measurement by unfolding a Gaussian resolution function of the coincidence circuit. If the time variation of the intensity of the photon beam is assumed to be a Gaussian function, then the rms value of that Gaussian is found to be less than 1.5×10−9 second.
A calculation by Lloyd Smith indicates that the measured radio-frequency fine structure should provide a rather accurate picture of the phase-stable bunch of electrons at the end of the acceleration period.
Apparatus for Studying Friction and Sliding Electrical Contacts
Authors: Flom D. G. 
Published: February 2005

Apparatus for the study of friction and sliding electrical contacts is described in detail. The equipment is designed for precise atmospheric control, a feature proven to be essential in any study of sliding contact phenomena.
Examples are given of the type of results obtained with this apparatus when used in frictional studies. The kinetic friction is recorded by a sensitive strain gauge system which indicates transient effects, due to the variations in surface conditions, within a single revolution of the test cylinder under the rider.
Proton Linear-Accelerator Injector for the Bevatron
Authors: Cork Bruce 
Published: February 2005

The Bevatron requires an intense source of high-energy protons. The machine should accept monoenergetic protons for a duration of approximately 500 microseconds once every 6 seconds. To satisfy the requirements of small loss due to scattering by the gas in the accelerating chamber, a 9.9-Mev linear accelerator has been built and operated.
A 500-kilovolt Cockcroft-Walton generator is used to inject 3-ma peak proton current into the linear accelerator. Focusing grids intercept approximately half of the injected beam. Additional losses, including radial defocusing and acceptance phase angle, result in a peak accelerated beam of 225 microamperes. The energy spread of the accelerated protons has not been measured, but an upper limit is less than ±30 kev.
Absolute Electrostatic Voltmeter of Hemispherical Concentric Electrodes
Authors: Malpica José Mireles 
Published: February 2005

The resultant force of electrostatic attraction between two concentric hemispherical electrodes can be determined rigorously, and it is a suitable arrangement for an absolute electrostatic voltmeter.
The curved electrodes have great mechanical rigidity and constancy of form.
Stability of balance between the electrostatic and mechanical forces, elimination of the error introduced by the width of separation between the moving electrode and the guard electrode, and other unexpected advantages were obtained by their use.
Catullus 63: A 'Hellenistic Poem'?
Authors: Harder Annette 
Published: February 2005

AbstractThis article gives a survey and analysis of the Hellenistic elements in Catullus 63. After a description of the poem's Hellenistic background it is argued that in this poem Catullus makes a selective, but careful and creative use of Hellenistic elements, with a certain focus on the means of allusion and Kreuzung der Gattungen. In doing so he alerts the reader to the poem's position within the literary tradition and within his own corpus. The meta-poetic aspects of his treatment of Hellenistic elements may require further exploration.