bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear Inclusions Found in Endometrium Medroxyprogesterone Acetate Therapy
Authors: Roberts D. K. , Powell L.C. , Busby Nola
Published: June 2020

Medroxyprogesterone Acetate is currently under clinical evaluation for use as a contraceptive agent. At the University of Texas Medical Branch in Galveston, Texas, 1,065 females in the reproductive age group have been given this agent. Intramuscular injections of 150 mgm in depot form have been given at three month intervals. The experience involves over 14,000 woman months of successful contraception.

Concurrent with this large study, endometrial biopsies have been taken on sixty selected patients and categorized at 5-day intervals so that a minimum of three biopsies at each time period were included. These biopsies were submitted to light and electron microscopic evaluation. Preliminary evaluation of this biopsy series has revealed unusual nuclear inclusions at the ten and fifteen day post-injection interval (Figure 1.).
Comparative Morphology of Intercellular Bridges Between Developing Germ Cells of the Ovary
Authors: Ruby J. R. , Dyer R. F. , Skalko R. G. , Gasser R. F. , Volpe E. P.
Published: June 2020

An electron microscope examination of fetal ovaries has revealed that developing germ cells are connected by intercellular bridges. In this investigation several species have been studied including human, mouse, chicken, and tadpole (Rana pipiens). These studies demonstrate that intercellular connections are similar in morphology regardless of the species.

Basically, all bridges are characterized by a band of electron-dense material on the cytoplasmic side of the tri-laminar membrane surrounding the connection (Fig.l). This membrane is continuous with the plasma membrane of the conjoined cells. The dense material, however, never extends beyond the limits of the bridge. Variations in the configuration of intercellular connections were noted in all ovaries studied. However, the bridges in each individual species usually exhibits one structural characteristic seldom found in the others. For example, bridges in the human ovary very often have large blebs projecting from the lateral borders whereas the sides of the connections in the mouse gonad merely demonstrate a slight convexity.
A Scanning Electron Microscope Study of Washer-Dryer Abrasion in Textiie Fibers
Authors: R. Goynes Wilton
Published: June 2020

The reaction of cellulose with certain cross-linking agents has produced cotton fabrics with outstanding durable press characteristics. However, many of these reactions decrease the natural abrasion resistance of the fiber. Wet abrasion and dry abrasion are known to produce different types of damage in the cotton fiber. It was of interest to determine whether such differences occur in the machine washing and drying of cotton fabrics. To study this problem, both untreated and cross-linked cotton fabrics were made into trouser cuffs, washed repeatedly and line dried, or machine dried until extensive damage had occurred. The two reacted fabrics studied had been treated with dimethyloldihydroxyethyleneurea and tris(l-aziridinyl) phosphine oxide. Cuene solubility tests on ultrathin sections of fibers from th ese fabrics observed with the transmission electron microscope indicated that the fibers were uniformly cross-linked throughout.
Two Developments - A Superconducting Microscope Conversion and A Precision High Voltage Divider
Authors: Worsham R. E. , Mann J. E. , Richardson E. G. , Ziegler N. F.
Published: June 2020

Two elements in the chain of development for a 500 kV high resolution microscope have been completed for initial experimental evaluation. They are a conversion of a Siemens Elmiskop I to use a superconducting objective lens and a 150 kV precisely regulated accelerating supply.

The superconducting microscope, shown in Fig. 2 is designed as an optical bench for proving the cryostat, lenses, stage mechanism, and other parts prior to the design of a superconducting column for 500 keV. The lens as shown in Figs. 1 and 2 mounts on the removable bottom plate of the 7-liter helium vessel. The vessel is supported and can be clamped rigidly by the four sets of G-10 epoxy-glass posts. Radiation Shields I and II are concentric with the helium vessel. They are cooled by the boil-off helium vapor to about 30 and 130°K, respectively. All electrical leads are carried into the helium vessel through the four symmetrically located vents. Cooldowns from 77°K requires about 30 liters of liquid helium and the boil-off rate is 0.3-0.5 1/HR at either 4.2 or ∼ 1.8°K.
Electron Source For High-Resolution Video Recording Using Directly Heated Lanthanum Hexaboride Emitter
Authors: Wolter Reinhard F. , Sanders Kenneth
Published: June 2020

An electron source featuring high brightness and long life has been developed for high-resolution video recording. The electron source is of triode type, and incorporates a directly heated and replaceable lanthanum hexaboride (LaB6) emitter.

Since the initial work of Lafferty (1) in 1951, LaB6 has been known as a potential long-life emitter material capable of high emission densities. However, a number of drawbacks have prevented widespread application as a cathode material. These include the high reactivity of LaB6 at elevated temperatures with almost all substrate materials, its sensitivity to corrosion by oxygen-containing gases (2), and fabrication problems due to Its brittleness. Successful operation at high emission densities, therefore, has been reported only by Kapitza, et al (3), and by Broers (4). Kapitza soldered an LaB6 cube to a tantalum heater using MoSi2 in vacuo at 2000°C. This system required a heating current of 50 A. Broers brazed an LaB6 rod to a copper heatsink and indirectly heated the tip of the rod by means of a tungsten coil requiring a power input of 60 W.
A Tilting Cold Stage For The AEI EM802
Authors: Swann P.R. , Swann G.R.
Published: June 2020

A tilting cold stage of unique design and with exceptional facilities has been developed commercially for the AEI EM802. The design consists of a double tilting stage allowing ±25° of specimen tilt about two orthogonal axes, with specimen cooling to any temperature in the range -150°C to room temperature. Since the specimen plane is maintained at the normal focal position of the objective lens and ‘bumping’ is eliminated by the circulation of gaseous rather than liquid nitrogen, the high resolution of the microscope is maintained.

The apparatus consists of a translation stage, A, containing all the tilting controls, a simple specimen cartridge, B, and a hollow annulus, C, clamped to the translation stage, through which flows the cooling gas from the liquid nitrogen Dewar, D.
Preparation of Samples for Scanning Electron Microscopy
Authors: Russ J. C. , Kabaya A.
Published: June 2020

One of the major advantages of the SEM in material studies is the ease of specimen preparation. For many samples it is only required to cut the sample to size and/or mount it in a suitable holder. However, it is necessary for some materials ( and desireable for others ) to consider other preparation variables:

Cleaning : When the sample is mechanically strong enough to withstand it, cleaning in a sonic cleaner is the best way to remove surface dirt. Solvents used in this operation, or for a simple flushing of the surface, should be selected to not leave a residue. Dusting with a Freon jet is the minimum cleaning to be considered.

Mounting: For small samples silver paint provides a strong, conductive attachment. Particles that would sink into this can be sprinkled onto doublesided Scotch tape. If the particles themselves do not require coating, the tape can be coated first and retain some adhesion.
Quality of the Secondary Electron Image at Low Accelerating Voltage
Authors: Kosuge T. , Hashimoto H. , Sato M. , Kimoto S.
Published: June 2020

A scanning electron microscope is usually operated at the accelerating voltage of 25 kV or so. The use of a lower accelerating voltage has many advantages to improve the image quality, such as presentation of fine details of the specimen surface, the prevention of the charge-up and that of the damage to the specimen by electron beam bombardment. In this paper, the quality of the secondary electron image is discussed under various accelerating voltages between 1 and 25 kV.

As far it is considered that the limit of the resolution of a secondary electron image is only depend on the diameter of the incident electron probe, the higher accelerating voltage is prefered. Attainable resolutions in this experiment for various voltages are shown in Figure 1. However, as shown in Figure 2 most of the secondary electron images in which a critical resolution is not necessary reveal fine image detail with better contrast at lower voltages.
A Means to Overcome the Contrast Difficulties Inherent to Scanning Electron Microscopy
Authors: Saffir Arthur J. , Woolley Tyler A. , Yew Nelson
Published: June 2020

The secondary electron image of the scanning electron microscope is similar to a light image of a three dimensional specimen. These two forms of "illumination", light and secondary electrons, have in common a contrast characteristic that makes photography or SEM micrography difficult. .. a tendency toward extreme highlights. The photographer encounters this phenomenon if his subject has a shiny surface, e.g., an automobile bumper. He overcomes this problem with dulling spray to suppress the undesirable highlights (reflections).

This problem is also common in SEM studies, especially with biological specimens of poor conductivity. It is undesirable or impossible to subject thermolabile or living specimens to the deposition of conductive coatings.
Irradiation Cascade Threshold Energy in Gold
Authors: Weber D.E. , Hines R.L.
Published: June 2020

Xenon ions, Xe131, were used to bombard 200A thick, (100) single crystal gold film in a non-channeling direction at room temperature. The incident ion energy was In the 2-40 kev energy range. The ion beam had a uniform current profile which was monitored in two directions before and after the bombardment. The Ion dose levels were of order 1×1010/cm2.

The resultant damage was viewed at room temperature in an Hitachi HU 11A electron microscope operated at lOOkev using 200 weak beam techniques. The micrographs of FIG. 1(a) and 1(b) are of the same area at different deviations. FIG. 1(a) represents the image of the damage at low deviation. The high deviation weak beam image is shown in FIG.
Heavy Ion Bombardment of Stainless Steel
Authors: Laidler J. J.
Published: June 2020

A problem of current concern in the design of liquid-metal cooled, fast breeder reactors (LMFBR) for commercial power generation is the volumetric expansion of structural components due to the agglomeration of vacancies produced during irradiation. Present plans call for LMFBR fuel cladding and major structural components to be fabricated of an austenitic stainless steel; with operating temperatures and fuel cycles now anticipated, projected values of the volumetric expansion in fuel clad at the end of a fuel cycle are as high as 10-12%. The attainment of such fluences in present test reactors is costly and time-consuming, requiring an irradiation time of some 4-5 years.
The Structure of an Incoherent Annealing Twin Boundary in FCC Alloys
Authors: Oblak J. M. , Kear B. H.
Published: June 2020

Because of the simple crystallographic relationship between matrix and twin in FCC materials, an incoherent twin boundary can be thought of in terms of an array of 1/6 <112> Shockley partials or 1/3 <111> Frank partials such as that shown schematically in Figure 1. Here the interface is made up of alternately spaced Frank partial s of opposite sign; however, these could be replaced with appropriate Shockley partials such that no far-reaching strain field is associated with the interface.
Measurement and Comparison of Relative Interfacial Energy Ratios in Ni and A Ni-Cr Alloy
Authors: Lin W.N. , Murr L.E.
Published: June 2020

Initially cold-rolled and annealed (15 min. at 1060°C) sheet specimens of 0.004 in. thick nickel (99. 86%) and 0.005 in. thick nickel-chromium alloy (78% Ni, 20% Cr, 0.3%Mn, 1.7% Si) were electropolished to a thickness of 1000-3000 Å in a solution containing 240cm3 H2O, 340 cm3 H2SO4 and 420 cm3H3PO4. Coherent twin-grain boundary inter sections in these Ni and Ni-Cr alloy thin films were examined by transmission and diffraction microscopy. Figs. 1 and 2 illustrate the typical twin-grain boundary intersecting systems observed in Ni and Ni-Cr alloy thin foils respectively. The ratios of twin boundary free energy to grain boundary free energy, γtb/γgb, were measured by using the techniques outlined by Murr and Murr, et al.
The Ordered Phase Formation in Ti-Al-Ga Alloys
Authors: Fujishiro Shiro , Gegel Harold L.
Published: June 2020

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.

The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization
Electron Microscopy of Spinodal Alloys
Authors: Livak R. J. , Thomas G.
Published: June 2020

Transmission microscopy, electron diffraction and scanning microscopy were used to study directly the microstructure of spinodal alloys and to correlate the fracture mode of aged tensile specimens with the microstruetural changes. The kinetics of spinodal decomposition for two copper-nickel-iron alloys were experimentally studied by heat treating specimens as described by Butler and Thomas. The aging times inside the spinodal ranged from one minute to 1000 hours. Thin foils for transmission electron microscopy were prepared by first using a chemical polish containing nitric, hydrochloric and acetic acids and then by electropolishing in a chromic oxide-acetic acid solution.
Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates
Authors: Murr L. E. , Wong G.
Published: June 2020

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.
Observations of Titanium Alloy Corrosion in Hot Saline Water
Authors: Fraker A. C. , Ruff A. W.
Published: June 2020

This work was conducted as part of a program to study materials which have potential use in desalination plants. Titanium has shown excellent corrosion resistance in neutral saline waters and it is important to know more about the corrosion process and how it might be influenced by other variables of the corroding system. Transmission electron microscopy has been employed to study uncorroded and corroded thin foils. This investigation concentrated on studying the initial stages of saline water corrosion by determining the morphology and composition of the oxide films and by checking the effects of increased temperatures, increased pressures and alloy composition on the corrosion process.
Transmission Electron Microscopy of Green Sheet Ceramic Specimens Prepared by Ultramicrotomy
Authors: Anderson Ronald M. , Schneider Fred W.
Published: June 2020

It is often desirable to make high-magnification observations of the internal structure of green sheet ceramic. Scanning electron microscopy and replication microscopy have been unsatisfactory in studying the structure of green sheet ceramic. The feasibility of another technique, that of combining ultramicrotomy with transmission electron microscopy (TEM), seemed, therefore, worth investigating. Mullite and alumina green sheets were studied.

Narrow (1 × 10mm) strips of green sheet ceramic were cut and mounted in “Beem” microtome capsules. A mixture of Cargille NYSEM epoxy embedding materials was prepared and poured into the capsules, care being taken to keep the specimen centered, especially at the tapered end of the capsule.
Electron Microscopy of Fracture Chips of SiC
Authors: Stevens R.
Published: June 2020

Specimens of silicon carbide were fractured over the temperature range 0 - 110°C under four point loading conditions. Plastic carbon replicas were made of the fracture surface and these were found to contain fracture chips which were transparent to the 200 kV electron beam. A small number of the fracture chips were found to contain dislocations and stacking faults, the description of these forming the basis of this work. The fracture chips were found to be mostly (ß SiC, although the β phase was sometimes found in the thicker chips, which were unfortunately not transparent, or so irregularly shaped as to be useless for transmission work.
Transformation from Fibrillar to Lamellar Morphology in Stretched Natural Rubber
Authors: Yeh G. S. Y. , Luch D.
Published: June 2020

We wish to report a fibrillar to lamellar transformation occurring in highly stretched (∼800%) thin films of natural pale crepe rubber when they are further supercooled to below room temperatures in the stretched state. The fibrillar crystals initially present throughout the stretched rubber at room temperature are oriented along the stretch direction. Upon cooling, the fibrils are replaced by crystals oriented perpendicular to the stretch direction. Since it is a well established fact that natural rubber is almost fully crystallized upon stretching to high elongations at room temperatures, attaining its near maximum crystallinity of about 30%, the change in morphology must then be primarily due to some sort of molecular rearrangement (recrystallization) process in the extended solid state.
Thermally Activated Nucleation and Faceting in Immiscible Cu-Cr thin Films
Authors: Staudhammer K. P. , Murr L. E.
Published: June 2020

The use of the electron microscope as an experimental chamber in which nucleation and growth observations can take place simultaneously has allowed in-situ studies to be performed on Cu-Cr thin films. Detailed investigations of the time-temperature sequence of events occurring during phase separation of two immiscible materials have been recorded on motion picture film. Each stage in the process of thermally induced phase separation of these thin films has been examined and characterized.

Co-evaporation and deposition of Cu-Cr at ambient temperatures on freshly cleaved (100) NaCI substrates results in a polycrystalline two-component structure such as shown in Fig. I(a) where the average particle size was less than 100A. Microprobe data showed the composition of the co-evaporated film to be 59.4 Cu - 40.6 Cr. The advantage of working with unsupported nucle-ation of films of immiscible materials as compared to other techniques of substrate supported nucleation studies lies in the inherent nature of immiscible materials. Because surface diffusion is a controlling mechanism, nucleation, faceting and subsequent growth are more rapid. Exsolved parti-cles once nucleated are three dimensional with minimal constraints, and are on the surface of the thin film as compared to platelet geometries obtained from nucleation and growth on most substrate-type investigations.
Scanning Electron Diffraction Attachment with Energy Filter
Authors: Barden L. F. , Gray J. Craig
Published: June 2020

The advantages of scanning electron diffraction with electron energy filtering over conventional electron diffraction have been fairly widely described, and, more recently, the use of such systems in conjunction with transmission electron microscopes has been reported. By means of scanning diffraction, the electron intensities in a diffraction pattern may be measured and plotted directly on an XY recorder without the inaccuracy and inconvenience of the normal photographic-densitometric process; and the use of an energy filter to remove electrons that have suffered an energy loss allows direct measurement of the diffracted intensities of the elastically-scattered electrons. In this paper, we describe a Scanning Electron Diffraction Attachment (SEDA) with electrostatic energy filter that has been constructed for use with the AEI EM6 and EM8 series of electron microscopes.
Studies on Water in the Hydration Chamber of a Modified Electron Microscope
Authors: Moretz R. C. , Hausner G. G. , Parsons D. F.
Published: June 2020

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.

Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.
Pressurized Specimen Chamber for Electron Microscope
Authors: Fukami A. , Etho T. , Ishihara N. , Katoh M. , Fujiwara K.
Published: June 2020

Electron microscopic observation is confined to dry specimens because the specimen must be kept in vacuum. To extricate themselves from this restriction, several researchers have developed a pressurized specimen chamber which, however, is not satisfactory in reliability; for example,

(1) The Lenard window film is not stable,

(2) The atmospheric layer is not so thin as the spacer because of the bend of the Lenard window film,

(3) Operation is not easy.

Under these circumstances, we have developed a new pressurized specimen chamber, considering the following points;

(1) Strength of the Leanard window films against pressure and electron bombardment,

(2) Applicable condition for wide field of research, Ease of opration.

(3) Ease of opration.
Combined High Resolution Electron Microscopy and X-Ray Microanalysis
Authors: Cooke C. J. , Openshaw I. K.
Published: June 2020

The Analytical Microscope EMMA-4 combines the function of high resolution electron microscopy with the facility of x-ray microanalysis. The microscope is a commercially available version of similar instruments which have been previously described. The design of the main console is based on the AEI EM802 with the rear panel suitably modified to house extra controls. An additional console houses the spectrometer controls and affords easy access to the pulse counting electronics. A chart recorder is mounted separately on a mobile trolley.

The Figure shows the electron optical column of the instrument and the position of the two x-ray spectrometers. The objective lens accommodates a side entry specimen stage which permits six specimens or standards to be loaded into the instrument at any one time. By using the normal projector system of the EM802 a direct magnification of about 140,000 times is possible and the resolution is better than 10Å.
Epitaxial Growth of β SiC on Si: Growth Defects
Authors: Leamy H. J. , Mogab C. J.
Published: June 2020

The reaction of single crystalline Si with gaseous acetylene at elevated temperatures produces thin, epitaxial, β SiC overgrowths. These films invariably contain growth defects which limit their utility in device applications. We have studied the structure of the defects in β SiC films formed under various growth conditions by SEM, STEM, and TEM techniques. We conclude that the occurrence of defects is intrinsic to the mechanisms of film growth, and that their number density, size, and structure may be controlled by altering the reaction conditions.
A Study of Gold Deposits on (001) Molybdenum Substrates
Authors: Price C. W.
Published: June 2020

Several Au deposits on (001) Mo surfaces were examined by reflection electron diffraction (RED), single-stage parlodion replicas, extraction replicas, and selected-area electron diffraction (SAD). The deposits were formed with a Knudsen effusion cell in an ultrahigh vacuum system capable of 1 × 10-10 Torr. The Mo crystals were baked several hours at ∼ 1050 C, and the depositions were made at various substrate temperatures. In spite of intensive precautions, evidence of an unidentified crystalline film frequently appeared in the RED patterns. The contamination was suspected to form by the decomposition of light hydrocarbons that were not trapped by molecular sieves, and it was eventually eliminated by the use of a titanium gettering system.
Epitaxy of Molybdenum on Sapphire
Authors: O'Neal J. E. , Rath B. B.
Published: June 2020

Thin films of molybdenum were deposited by the electron beam evaporation method on single crystal sapphire substrates to establish the effects of substrate orientation, deposition temperature, and evaporation rate on the structure, orientation and morphology of the deposited films. The films were characterized by replication and high resolution reflection electron diffraction methods.

The epitaxy of molybdenum on sapphire substrates of orientations (0001), (1012), and (1012) were studied over a substrate temperature range of 25 through 1000°C with deposition rates of 500 and 1000 Å/min. Strain-free substrate surfaces were prepared by removing the disturbed surface layer by means of thermal etching in-situ at 1450°C for 2 hours in a pressure of 10−9 Torr.
Surface Films on Zircaloy-2 Samples Cracked in Neutral Aqueous NaCl by Stress Corrosion
Authors: Ploc R.A.
Published: June 2020

Samples of low-nickel Zircaloy-2 (material MLI-788-see(1)), when anodically polarized in neutral 5 wt% NaCl solutions, were found to be susceptible to pitting and stress corrosion cracking. The SEM revealed that pitting of stressed samples was occurring below a 2000Å thick surface film which behaved differently from normal zirconium dioxide in that it did not display interference colours. Since the initial film thickness was approximately 65Å, attempts were made to examine the product film by transmission electron microscopy to deduce composition and how the corrosion environment could penetrate the continuous layer.
A New Defect in Polyethylene Single Crystals
Authors: Thomas E. L. , Sass S. L.
Published: June 2020

In polyethylene single crystals pairs of black and white lines spaced 700-3,000Å apart, parallel to the [100] and [010] directions, have been identified as microsector boundaries. A microsector is formed when the plane of chain folding changes over a small distance within a polymer crystal. In order for the different types of folds to accommodate at the boundary between the 2 fold domains, a staggering along the chain direction and a rotation of the chains in the plane of the boundary occurs. The black-white contrast from a microsector boundary can be explained in terms of these chain rotations. We demonstrate that microsectors can terminate within the crystal and interpret the observed terminal strain contrast in terms of a screw dislocation dipole model.
Gold Decoration of Etched Polycrystalline KCl
Authors: Comer Joseph J. , Bergeron Charles
Published: June 2020

The gold decoration method described by Bassett was shown to be capable of displaying unit lattice steps on cleavage surfaces of sodium chloride. By this technique slip steps could be readily distinguished from cleavage steps. Bassett's technique was refined by others to include cleaving the crystal in vacuum and heating to obtain thermal etch patterns from which information on the sites and nature of dislocations could be deduced. Another use for the technique was to decorate PbCl2 inclusions in KCl where the resulting patterns suggested the presence of double electric layers surrounding the precipitate.
Studies of Laser-Metal Interactions using a Coupled Laser-SEM System
Authors: Magee T. J. , Krehl P.
Published: June 2020

With the advent of new high-power laser systems and the increasing variety of scientific, commercial, and military applications, a more detailed understanding of laser-metal interactions is required. Of particular importance are the induced surface damage, plasma-plume diagnostics, shockwave initiation, and internal structural damage during high-power pulsed laser loading.

In the present program, a Cambridge scanning electron microscope (SEM) has been modified to accept a focused laser beam into the sample cavity. An external high voltage relay, triggered from the frame generator at the start of the laser pulse, provides a finite time lag of 50 to 100 milliseconds before the onset of framing.
Diffusion of Zn into GaAs Inside the Transmission Electron Microscope
Authors: Rhines W. C. , Stevenson D. A. , Barrett C. R. , Anderson L. J.
Published: June 2020

A technique was developed to directly observe the dislocation generation that occurs during Zn diffusion into GaAs. The method is applicable to a wide variety of materials where phase transformations or lattice strain resulting from impurity diffusion is of interest, and where the need exists to observe the material while the transformation or strain is occurring.

Zinc diffusion in GaAs and other III-V compounds is of interest because of its application to the fabrication of light emitting diodes and injection lasers. Numerous reports exist in. the literature concerning the high density of dislocations (>108cm−2) and the presence of precipitates found in GaAs after Zn diffusion. Dislocations and/or precipitates seriously impair the performance of light-emitting devices.
Control of Metal Alloy Oxidation with Electric Fields
Authors: Dils R. R. , Follansbee P. S.
Published: June 2020

Electric fields have been applied across oxides growing on a high temperature alloy and control of the oxidation of the material has been demonstrated. At present, three-fold increases in the oxidation rate have been measured in accelerating fields and the oxidation process has been completely stopped in a retarding field.

The experiments have been conducted with an iron-base alloy, Pe 25Cr 5A1 0.1Y, although, in principle, any alloy capable of forming an adherent aluminum oxide layer during oxidation can be used. A specimen is polished and oxidized to produce a thin, uniform insulating layer on one surface. Three platinum electrodes are sputtered on the oxide surface and the specimen is reoxidized.
Influence of Thermo-Mechanical Processing on the Microstructure of Beryllia Dispersed Nickel Alloys
Authors: Grewal M.S. , Sastri S.A. , Grant N.J.
Published: June 2020

Currently there is a great interest in developing nickel base alloys with fine and uniform dispersion of stable oxide particles, for high temperature applications. It is well known that the high temperature strength and stability of an oxide dispersed alloy can be greatly improved by appropriate thermomechanical processing, but the mechanism of this strengthening effect is not well understood. This investigation was undertaken to study the dislocation substructures formed in beryllia dispersed nickel alloys as a function of cold work both with and without intermediate anneals. Two alloys, one Ni-lv/oBeo and other Ni-4.5Mo-30Co-2v/oBeo were investigated. The influence of the substructures produced by Thermo-Mechanical Processing (TMP) on the high temperature creep properties of these alloys was also evaluated.
Phase Transformations in Co5Sm
Authors: Rao P. , Smeggil J.G. , Koch E.F.
Published: June 2020

Much higher magnetic coercivities than were previously available have been attained with the compound Co5Sm. However, coercivity is very sensitive to heat treatment; in particular, annealing near 750°C substantially reduces coercivity. This has been attributed to a possible eutectoidal decomposition of Co5Sm into CO17Sm12 and CO7Sm12 on the basis of optical metallography. This possibility makes it necessary to obtain basic electron microstructural information from CO5Sm heat treated in this temperature range.

High quality Co5Sm crystals were annealed in sealed Mo bombs at 750°C for 10 days. Electron transparent specimens were prepared by ion thinning in a commercialion milling apparatus.
Minority-Carrier Diffusion Lengths in GaAs:Ge by Scanning Electron Microscopy
Authors: Levin Edwin R.
Published: June 2020

Scanning electron beam determinations of minority-carrier diffusion lengths in semiconductors have been viewed with some suspicion, because of uncertainty about the influence of surface recombination. We have recently made a series of observations which show that the bulk and surface effects can be easily separated, so that reliable volume diffusion lengths are obtained by the scanning beam method.

The specimens were GaAs diodes grown with varying concentrations of Ge in the p-layers. The diodes were cleaved normal to the pn junction and examined in a Cambridge Stereoscan, with the beam normal to the cleaved surface and linescanned in a direction perpendicular to the line of intersection of the junction with the surface.
Study of TE Puke Halloysite by a High Resolution Electron Microscope
Authors: McKee T. R. , Dixon J. B. , Whitehouse U. G. , Harling D. F.
Published: June 2020

Clay minerals normally exhibit platy morphology with basal spacings parallel to the surface of an aggregate and registering characteristic x-ray diffraction effects. For the same reason the majority of the electron microscopic lattice imaging has been accomplished using embedded and ultrathin sectioned clays, allowing the basal spacing to be correctly oriented with respect to the electron beam. Yada has observed lattice spacings in chrysotile (a tubular mineral) by direct examination.

Halloysite is a type of kaolin clay mineral that usually exhibits curved layers as tubes and spheroids which reduces the x-ray diffraction intensities from preferred orientation mounts while exposing the basal spacing for electron diffraction investigation and lattice imaging.
Early Silica Diagenesis in Volcanic and Sedimentary Rocks: Devitrification and Replacement Phenomena
Authors: Wise S. W. , Weaver F. M. , Guven N.
Published: June 2020

Although silica is a primary component of flints, cherts, volcanic glasses, and siliceous deep sea oozes, mobilization pathways and modes of reprecipitation of this element during early diagenesis of volcanic and sedimentary rocks remains an elusive geologic problem. As a result, the source and mode of deposition of vast Tertiary silica deposits of the Atlantic and Gulf Coastal Plain and offshore deep sea deposits is currently a topic of sharp debate. Both volcanic and biogenous sources of silica have been variously postulated as ultimate or immediate silica sources for a broad range of fine-grained silica-rich rocks including claystones, “opal claystones,” “buhrstones,” “pseudobuhrstones,” cristobalitic cherts, and silicified chalks and limestones. Current scanning electron microscope/electron microprobe investigations of incipient stages of diagenesis in geologically young biogenous sediments, volcanic glasses, and silica-replaced carbonate rocks, however, do allow silica pathways to be traced and silica sources to be ascertained.
Application of a Simple Cold Stub to the Direct Observation of Frozen Hydrated Sand
Authors: Wehrung John M. , Harniman Richard J.
Published: June 2020

Water tables in aquifer regions of the southwest United States are dropping off at a rate which is greater than can be replaced by natural means. It is estimated that by 1985 wells will run dry in this region unless adequate artificial recharging can be accomplished. Recharging with surface water is limited by the plugging of permeable rock formations underground by clay particles and organic debris.

A controlled study was initiated in which sand grains were used as the rock formation and water with known clay concentrations as the recharge media. The plugging mechanism was investigated by direct observation in the SEM of frozen hydrated sand samples from selected depths.
Element and Compound Distribution Mapping in the SEM
Authors: Russ J.C. , Barnhart M.W. , Christopher J.L.
Published: June 2020

For the high percentage of scanning electron microscopes equipped with x-ray analytical capability, a common mode of operation is the x-ray “dot image” to describe the distribution on the specimen surface of an element of interest. As with the conventional microprobe, this is done by displaying a pulse or dot on the display tube whenever an x-ray with an energy (or wavelength) corresponding to the element of interest is detected. By photographically integrating many of these dots, an image that correlates with other specimen images (e.g. backscattered or secondary electrons) is produced. When very many dots are recorded, the image may take on a continuous-tone appearance but, in general, it is possible to make only very rough qualitative estimates of relative intensity in different areas because the human eye does a very poor job of estimating dot density. Edges or other sudden changes are more easily recognized than gradual variations.
Low Z Elemental Analysis using Energy Loss Electrons in a Scanning Microscope
Authors: Johnson D. E. , Isaacson M.
Published: June 2020

Electron microprobe analysis has been used increasingly in, recent years for low Z analysis of thin biological sections. Although this technique has produced useful results, the sensitivity is limited by two main factors. First, the fluorescence yield (wK) decreases rapidly with decreasing Z. Using the value of wK (for carbon for example, only about one out of every 400 K ionizations in carbon results in a carbon x-ray. Second, this poor x-ray production efficiency is coupled with the inherently poor x-ray collection efficiency of most microprobe detectors. In thin sections the x-rays are emitted uniformly over 4TT steradians but the detector subtends only a small solid angle at the specimen. Hall estimates the collection efficiency of most diffracting detectors at 10−4 and, with the qualification of much lower peak to background ratios, he estimates the collection efficiency of solid state nondiffractive detectors as 10−4 to 10−2.
A Field Emission System For Transmission Electron Microscopy
Authors: Troyonal Michel , Kuoal Huei Pei , Siegelal Benjamin M.
Published: June 2020

A field emission system for our experimental ultra high vacuum electron microscope has been designed, constructed and tested. The electron optical system is based on the prototype whose performance has already been reported. A cross-sectional schematic illustrating the field emission source, preaccelerator lens and accelerator is given in Fig. 1. This field emission system is designed to be used with an electron microscope operated at 100-150kV in the conventional transmission mode. The electron optical system used to control the imaging of the field emission beam on the specimen consists of a weak condenser lens and the pre-field of a strong objective lens. The pre-accelerator lens is an einzel lens and is operated together with the accelerator in the constant angular magnification mode (CAM).
Particulate Collection from Aircraft Turbine Exhaust
Authors: Dumais Maurice W.
Published: June 2020

Prior to this work, very little had been done using transmission electron microscopy to study the physical characteristics of exhaust particles. At least one major aircraft engine manufacturer has attempted to replicate samples for analysis by transmission electron microscopy. Some tests in the past included analysis of submicron particulates collected on millipore filters. In particular, the use of cellulose filters to obtain samples for analysis on scanning or transmission electron microscopes could produce mis- leading results. These filters are three-dimensional media. Their high collection efficiency at small particle diameters is largely due to the fact that most of the smaller particles are impacted below the surface, somewhere on the spaghetti-like fibers which constitute the filter. Obviously, a scanning electron micrograph will not show these particles, and due to its limited resolution capabilities, cannot truly represent particles below a few hundred angstroms in diameter.
Techniques For Ultra-Thin Apertures
Authors: Eisner Paul R.
Published: June 2020

Ultra-thin apertures function longer with negligible astigmatic effect and require less maintenance than conventional thick apertures. They resist contamination because they are heated by the electron beam, and the ultrathin edge offers minimal area for formation of a charged layer of contamination. Ledbetter and Dell described making ultra-thin apertures by evaporating metal over spheres of dextran on a collodion membrane. An alternative procedure for making ultra-thin apertures is given in detail here along with a method for extending aperture life.

Ultra-thin apertures can be piade for less than the cost of conventional thick apertures. Copper specimen grids 2 or 3mm diameter with a circular opening 600μm diameter are coated with 50nm thick Formvar film according to the technique given by Bradley.
Combined Plasma-Microincineration, Electron Microscopy And Electron Probe Microanalysis For Fine Localization of Biological Mineral Substances
Authors: Thomas Richard S. , Corlett Mabel I.
Published: June 2020

Ash patterns produced by oxygen plasma microincineration(OPM) of thin-sectioned biological materials and examined with the transmission electron microscope (TEM) can show unambiguously the distribution of mineral substances in the specimen with resolutions down to 100 Å. The chemical nature of the mineral is not demonstrated, however. Electron-probe X-ray microanalysis (EXM), on the other hand, can determine precisely the nature of the mineral in ashgd or unashed sections but its spatial resolution is limited to 1000-10,000 A at best. Also its sensitivity of analysis on unashed specimens is limited by intolerance of the specimen to high beam intensities. Using both TEM and EXM together on ash patterns of suitable specimens can overcome their independent spatial and chemical limitations. Furthermore, use of OPM produces a highly stable mineral specimen for EXM, thereby improving sensitivity.
A Method For Maintaining Specimen Hydration by Sandwiching Between thin Films
Authors: Taylor Kenneth A. , Glaeser Robert M.
Published: June 2020

A major goal of electron microscopy is the visualization of biological specimens in the hydrated state. One method to maintain this specimen hydration is by sandwiching the specimen between thin hydrophilic support films and observing it frozen on a liquid nitrogen cooled stage. Sufficiently thin films of ice are produced so that the specimen can be observed embedded in the ice.

The formation of thin films of ice can be demonstrated by placing a drop of distilled water between two halves of a folding grid which has previously been coated with a thin hydrophilic support film.
Wide Field Electron Microscopy: Specimen Preparation
Authors: Yang Grace C. H. , Morrison A. B.
Published: June 2020

A slot grid with an elongated opening of 1 × 2 mm2 was coated with Formvar film as described by Pease. Instead of using the usual coarse screen to pick up the coated grids, a screen of 200 mesh nickel was laid on top of the coarse screen with the upper screen bent over the edges of the bottom screen. It was necessary to use this fine and flat screen to protect the film over the slot from sticking to the metal thread of the regular screen. No carbon coating was used. The 1 × 2 mm2 opening was too large to withstand the bombardment of carbon molecules. By using a 0.5% Formvar in ethylene dichloride, the film was reasonably durable. Pale gold sections were cut from a 1 mm wide and 1.5 mm long block face.
Ultrastructure of Call-Exner Bodies: Their Formation and Sequence
Authors: Baccarini Iracema M.
Published: June 2020

A granulosa cell tumor measuring 11 × 7.5 × 5 cms. from a 51 year old woman was studied by electron microscope. The cellular tumor consists of cells showing some morphological similarity to those of the granulosa cells of the normal developing follicles. The cells are packed one to another and are arranged in large groups encircled by thin bundles of connective tissue. Small pieces of tissue were taken from different areas of the tumor masses and quickly fixed in buffered 1% osmium tetroxide, embedded in Epon 812, and viewed in a RCA-MU electron microscope. The Call-Exner bodies were composed of fine granular amorphous substance which frequently contained one or more cells similar to those of the tumor, cells going to regessive process, and in many instances debris of cells.
Virus-Like Particles in a Human Breast Cancer: Structural Similarity to Previously Reported Particles
Authors: Kasnic G. , Stewart S. E. , Urbanski C.
Published: June 2020

We have reported the maturation of an intracisternal A-type particle in murine plasma cell tumor cultures and three human tumor cell cultures (rhabdomyosarcoma, lung adenocarcinoma, and osteogenic sarcoma) after IUDR-DMSO activation. In all of these studies the A-type particle seems to develop into a form with an electron dense nucleoid, presumably mature, which is also intracisternal. A similar intracisternal A-type particle has been described in leukemic guinea pigs. Although no biological activity has yet been demonstrated for these particles, on morphologic grounds, and by the manner in which they develop within the cell, they may represent members of the same family of viruses.
Immunoperoxidase Labeling of a Nucleolar Antigen in Human Melanoma Cells by Sera of Melanoma Patients
Authors: Miller M. F. , Bowen J. M. , Angermann J. , McBride C. M. , Dmochowski L.
Published: June 2020

We have previously demonstrated by the indirect immunofluorescence test that sera of some patients with malignant melanoma contain antibodies to antigens associated with nucleoli of their own and homologous melanoma cells. These studies have shown a correlation between the presence of nucleolar antigen in tumor cells of a melanoma patient, progressive tumor growth, and poor prognosis. The present study was undertaken to determine if nucleoli of melanoma cells possess any unusual morphological features and to demonstrate the nucleolar antigen at the light and electron microscope level by the immunoperoxidase reaction.

Melanoma cells from selected patients were examined by electron microscopy after growth in tissue culture.
Myeloblasts of Acute Granulocytic Leukemia
Authors: Marshall G. June , Kirchen Mary E. , Geddes Anne D. , Bateman Jos. R.
Published: June 2020

Acute granulocytic leukemia (AGL) is typified by a maturation arrest resulting from a synthetic block which is reflected in morphologically identifiable stages of maturation. In AGL's the marrow population primarily consists of two cell types: the myeloblast which is the least mature cell and one by definition which lacks lysosomes and the promyelocyte which contains lysosomes. Maturation beyond the promyelocyte is an aberrant process which results in a limited number of abnormal mature granulocytes. In order to better characterize the cells, marrows from 11 individuals with AGL have been studied at the LM and EM levels. All marrows were obtained prior to the initiation of chemotherapy. Fixation was with 5% gluteraldehyde in 0.1M cacodylate buffer. Osmication, dehydration and embedding were accomplished by standard methods. All marrows were reacted for peroxidase and acid phosphatase activity.