bluuebunny/crossref_metadata_2025 huggingface dataset:
Intramitochondrial Viruses of Reptilian Cell Origin
Authors: Lunger Philip D. , Clark H. Fred
Published: June 2020

In the course of fine structure studies of spontaneous “C-type” particle production in a viper (Vipera russelli) spleen cell line, designated VSW, virus particles were frequently observed within mitochondria. The latter were usually enlarged or swollen, compared to virus-free mitochondria, and displayed a considerable degree of cristae disorganization.

Intramitochondrial viruses measure 90 to 100 mμ in diameter, and consist of a nucleoid or core region of varying density and measuring approximately 45 mμ in diameter. Nucleoid density variation is presumed to reflect varying degrees of condensation, and hence maturation stages. The core region is surrounded by a less-dense outer zone presumably representing viral capsid.

Particles are usually situated in peripheral regions of the mitochondrion. In most instances they appear to be lodged between loosely apposed inner and outer mitochondrial membranes.
Tubular Structures in Endoplasmic Reticulum; Are They Viruses?
Authors: Baringer J.R. , Swoveland P.
Published: June 2020

Recently, tubular structures 18 - 26 nm in diameter have been found within endoplasmic reticulum (ER) of endothelial and other cells in a number of conditions including normal monkey tissue, renal biopsies from human lupus erythematosus and other diseases, a variety of sarcomas, lymphomas, and leukemias, and several viral infections both in vivo and in vitro. The structures have in common a convoluted tubular form, near uniform diameter, and general appearance suggesting a resemblance to the myxoviruses.

We have observed similar particles within the ER of endothelial cells within the cerebral lesions caused by herpes simplex virus (HSV) both in experimentally infected rabbits and in a human case of herpes simplex encephalitis.

Rabbits inoculated on the cornea with HSV developed focal encephalitic lesions in the brainstem within 4 days; cells within the lesions contained HSV.
Cytochemical Studies of Cell Wall Biosynthesis in Staphylococcus Aureus
Authors: Koike Masaatsu , Nakashima Koichi , Iida Kyoko
Published: June 2020

Penicillin exerts the activity to inhibit the peptide cross linkage between each polysaccharide backbone at the final stage of wall-peptidoglycan biosynthesis of bacteria. Morphologically, alterations of the septal wall and mesosome in gram-positive bacteria, which were occurred in early time after treatment with penicillin, have been observed. In this experiment, these alterations were cytochemically investigated by means of silver-methenamine staining after periodate oxidation, which is applied for detection of localization of wall mucopolysaccharide.

Staphylococcus aureus strain 209P treated with 100 u/ml of penicillin G was divided into two aliquotes. One was fixed by Kellenberger-Ryter's OSO4 fixative at 30, 60 and 120 min after addition of the antibiotic, dehydrated through alcohol series, and embedded in Epon 812 (Specimen A). The other was fixed by 21 glutaraldehyde, dehydrated through glycolmethacrylate series and embedded in glycolmethacrylate mixture, according to Bernhard's method (Specimen B).
Ultrastructural Changes in the Brain Following Local Application of Guinea Pig Serum
Authors: Bystrom Barbara G. , Costin Anatol , Ross Adey W.
Published: June 2020

It was previously reported that evoked potentials and impedance were diminished when guinea pig serum was introduced into the lateral geniculate body of the cat. The cats used in the present study were chronically implanted with electrodes and cannulae. Two hours after injection of 1 μl guinea pig serum directly into the lateral geniculate body, when electrophysiological changes were evident, the cats were sacrificed. The brains were perfused with phosphate buffered 2%Glutaraldehyde-2% formaldehyde after flushing with physiological saline. Post fixation was with 1% OsO4. Dehydration was carried out in graded Ethanol, and embedment was in Epon. The silver to silver-grey sections were intensified with uranyl acetate and lead citrate. In all cases, one lateral geniculate body was used for control and the other for experimental injection.

The electron microscopy study was done "blind" in that the treatment, if any, or the site of injection, if any, was unknown by the microscopist.
Optimizing Sectioning with Diamond Knives
Authors: Sawers J. R.
Published: June 2020

Du Pont diamond knives; although utilized in cataract surgery, precision machining and film slitting, are used primarily in ultra-microtomy. Today, we would like to describe our process for making diamond knives and then some results of our work optimizing sectioning procedures.

Our diamond knives are made from gem quality natural diamonds and as such can bear tremendous compressive forces but torque, lateral or tensile forces can easily fracture the blade edge. The first step in the manufacturing process is to cleave the diamond into slabs approximately 25 mils thick along the (111) plane. After cleaving, a diamond is soldered into a slotted shaft. The first grinding step, called “roughing”, begins by tapering one side of the shaft until the diamond just becomes visible, then the other side is tapered. Grinding continues until no nicks are visible at 50x. Next, “polishing” fine grinds the knife edge until it is “nick-free” at 600x.
A Method for Setting the Clearance Angle
Authors: Bucek Michael T. , Arnott Howard J.
Published: June 2020

It is believed by the authors, with supporting experimental evidence, that as little as 0.5°, or less, knife clearance angle may be a critical factor in obtaining optimum quality ultrathin sections. The degree increments located on the knife holder provides the investigator with only a crude approximation of the angle at which the holder is set. With the increments displayed on the holder one cannot set the clearance angle precisely and reproducibly. The ability to routinely set this angle precisely and without difficulty would obviously be of great assistance to the operator. A device has been contrived to aid the investigator in precisely setting the clearance angle. This device is relatively simple and is easily constructed. It consists of a light source and an optically flat, front surfaced mirror with a minute black spot in the center. The mirror is affixed to the knife by placing it permanently on top of the knife holder.
Scanning Electron Microscopy of the Denticles and Eggs of Ascaris lumbricoides and Ascaris suum
Authors: Ubelaker John E. , Allison Venita F.
Published: June 2020

Morphological differences between Ascaris of human and porcine origins have been difficult to detect. Sprent has distinguished the two species by the characteristics of the denticles observed by light microscopy. The present study is concerned with the differences in morphology of the denticles and with the examination of the ova of the two species as revealed by scanning electron microscopy.

Hospital and slaughter house specimens were acquired locally, fixed in phosphate buffered paraformaldehyde and stored in 70% ethanol overnight. Preparative procedures for scanning electron microscopy were as previously reported. Specimens were examined in a JEOL JSMU-3 scanning electron microscope.

The denticles of Ascaris suum are regular in distribution and conoid in shape (Fig. 1, A and B). Each denticle is cuspid; no multiple cusps were observed. The “molar teeth” forms previously described probably result from observations of cusps from which adhering debris was not removed in preparation.
Frozen Resin Cracking Method for Scanning Electron Microscopy and its Application to Cytology
Authors: Tanaka K. , Iino A.
Published: June 2020

Until recently, a few reports have been published as to the methods for observing intracellular structure by means of scanning electron microscopy. Makita and Sandborn saw intracellular granules in the glands of the hen oviduct with tissue sections by means of Smith-Farquhar tissue sectioner. Geminario and McAlear applied the freeze-fracturing technique in order to ascertain the intracellular structure of retinas from mice.

A new method, attempted by us, embedding the materials in epoxy resin and cracking it into two pieces after freezing, is described below with its application to cytology.

1. The pieces of tissue are fixed in glutaraldehyde and osmium tetroxide.

2. They are dehydrated by graded series of ethanol and propylen oxide.

3. Then they are embedded in small gelatin capsules (size no. 2) which are filled with Cemedine 1500 (epoxy resin) without any catalysts (Epon 812 or Rigolac can be used but the temperature for hardening them is very low, -80°C).
Preparation of Red-Green Stereo Lantern Slides from SEM Micrographs
Authors: Nemanic Michael
Published: June 2020

The procedure detailed allows the projection and viewing of stereoscopic slides without the use of a special stereo projector or a polarizing screen; a standard lantern slide projector is used, and the slides are viewed through red and green acetate filters.

A stereo pair is taken on a scanning electron microscope with a tilt difference of 7° (Fig. 1). After the first member of the pair is taken, the sample is tilted. The image is refocused by means of the z-axis control and recentered by means of the x- and y-axis controls. These two manipulations ensure that both micrographs in the stereo pair are at the same magnification and that they will be superimposed properly on the color slide.

A Polaroid MP-3 Industrial Viewer, a Graflex 120 roll film back, and a framing table (or equivalent equipment) can be used to make stereo slides from stereo pairs.
A Field Emission Scanning Microscope
Authors: Suganuma T. , Hashimoto H.
Published: June 2020

A preliminary model of the field emission scanning microscope has been developed. Figure 2 shows a schematic construction of an electron optical system and specimen chamber of the instrument. An electron gun system has double vacuum chambers(inner and outer) which are independently evacuated by the ion pumps 20 l/s ea. Viton gaskets are used for the outer chamber and no gaskets for the inner chamber. The flange of inner chamber is finely ground and fits to the seat so that it cut off gas flow from the outer chamber except that through a small aperture(∼0.1 mm) of an anode. The sliding of the ground fitting makes it possible to move the position of a tip in the inner chamber. As no metal gasket is used for gun chamber, the replacement of the tip is easily accomplished. The chambers are baked out by an internal heater arranged in the outer chamber.
Enhancement of EDAX Spectra from TEM and SEM Analysis
Authors: Russ John C.
Published: June 2020

The attachment of EDAX systems to the TEM and SEM makes possible the microanalysis of features observed in the high magnification images. In general the interpretation of the resulting spectra is very straightforward, with qualitative identification of the major and minor elements present requiring only reference to a simple chart, and semiquantitative estimation of concentration possible by direct comparison of peak heights. True quantitative analysis requires more complex mathematics and/or standards but this is not generally the aim of most SEM and TEM users.

There is one class of problems for which the direct interpretation of the recorded EDAX spectrum can be difficult, especially for the operator not highly trained in EDAX methods. This is the case of very low total count rates, typically encountered with low concentrations of elements in organic matrices and/or with low total specimen mass as encountered with thin sections.
Transmission Scanning Electron Microscopy and Energy Analysis with the Siemens ELMISKOP 101
Authors: Thieringer H. M.
Published: June 2020

It has repeatedly been show that with conventional electron microscopes very fine electron probes can be produced, therefore allowing various micro-techniques such as micro recording, X-ray microanalysis and convergent beam diffraction. In this paper the function and performance of an SIEMENS ELMISKOP 101 used as a scanning transmission microscope (STEM) is described. This mode of operation has some advantages over the conventional transmission microscopy (CTEM) especially for the observation of thick specimen, in spite of somewhat longer image recording times.

Fig.1 shows schematically the ray path and the additional electronics of an ELMISKOP 101 working as a STEM. With a point-cathode, and using condensor I and the objective lens as a demagnifying system, an electron probe with a half-width ob about 25 Å and a typical current of 5.10-11 amp at 100 kV can be obtained in the back focal plane of the objective lens.
Resolution in the Scanning Transmission Electron Microscope
Authors: Thomson M. G. R.
Published: June 2020

The variation of contrast and signal to noise ratio with change in detector solid angle in the high resolution scanning transmission electron microscope was discussed in an earlier paper. In that paper the conclusions were that the most favourable conditions for the imaging of isolated single heavy atoms were, using the notation in figure 1, either bright field phase contrast with β0⋍0.5 α0, or dark field with an annular detector subtending an angle between ao and effectively π/2.

The microscope is represented simply by the model illustrated in figure 1, and the objective lens is characterised by its coefficient of spherical aberration Cs. All the results for the Scanning Transmission Electron Microscope (STEM) may with care be applied to the Conventional Electron Microscope (CEM). The object atom is represented as detailed in reference 2, except that ϕ(θ) is taken to be the constant ϕ(0) to simplify the integration. This is reasonable for θ ≤ 0.1 θ0, where 60 is the screening angle.
A Study of the Effect of Arcs on Wires by Scanning Electron Microscopy
Authors: Parker Marie T.
Published: June 2020

Several years ago our laboratory became interested in determining the size of the smallest electrical arc we could find evidence of by electron microscopy. We failed lengths of Octopus Cable from twisted pairs by shorting under varying known minimum conditions, then discovered that the required replica techniques for transmission electron microscopy (TEM) for such small details would not provide practical information in a reasonable period of time. However, our interest in small arcs continued. Later, we were able to look directly at damaged areas of the failed cables mentioned above using scanning electron microscopy. Observations of two of these areas will be reported here.

The first arc was produced by increasing the current through two cables until the plastic insulation ruptured and individual strands of wire melted, some of which then fused together and later broke apart again - a drastic action.
100 KV Scanning Microscope
Authors: Crewe A. V. , Retsky M. W.
Published: June 2020

A 100 kv scanning transmission microscope has been built. Briefly, the design is as follows: The electron gun consists of a field emission point and a 3 cm Butler gun. The beam has a crossover outside the gun and is collimated by a condenser lens.

The parallel beam passes through a defining aperture and is focused by the objective lens onto the specimen. The elastic electrons are detected by two annular detectors, each subtending a different angle, and the unscattered and inelastic electrons are collected by a third detector. The spectrometer that will separate the inelastic and unscattered electrons has not yet been built.

The lens current supplies are stable to within one part per million per hour and have been described elsewhere.

The high voltage is also stable to 1 ppm/hr. It consists of the raw supply from a 100 kv Spellman power supply controlled by an external reference voltage, high voltage divider, and error amplifier.
Electron Opacity Measurements Applied to Film Growth Kinetics
Authors: Zahavi J. , Metzger M.
Published: June 2020

Studies are being made of the topography and structure of thin porous amorphous anodic films on aluminum during growth in sulfuric acid at a low current density, with reference to film stability and breakdown. Certain questions regarding the rate of growth can be answered through measurements of electron opacity, and this has been applied to show that the presence of chloride in the electrolyte, the surface preparation before anodizing and the current density can influence formation efficiency even when no change is apparent in film structure or electrochemical behavior. Electron opacity combined with transmission microscopy has been used very effectively in certain kinetic studies.

The opacity was determined on a HU-11A microscope at 100 KV by substituting in the specimen chamber a current measuring specimen holder (CMSH) built by R. J. Anderson. This was insulated from the column and grounded through an electrometer, which read the absorbed current, IAB, The beam current, Io, could be determined in various ways.
The Microstructure of Sputtered Semi-Conductor Glass Films
Authors: Braski D. N. , Early B. F.
Published: June 2020

Films of GeO2 - 16% P2O5 - 8% V2O5 glass from 200 to 300 Å thick were produced by a technique utilizing radiofrequency (RF) sputtering. The GeO2 glass was RF sputtered onto highly polished substrates that were previously vacuum coated with a parting agent (fluorescein or phenolphthalein). Acetone was used to separate the water-soluble GeO2 glass film from the substrate. A transmission electron micrograph of a typical GeO2 glass film is shown in Fig. 1. The film exhibits an equiaxed structure with particles approximately 0. 1 μ in diameter. The crystal structure was amorphous as determined by selected area electron diffraction. Films such as this usually displayed good thickness uniformity and generally were very clean. However, films frequently broke up during separation in acetone. Film breakage was attributed to the combined effects of residual stresses and flaws which were found in most of the GeO2 glass films.
The Effects of Annealing on the Grain Growth and Surface Rearrangement of Electroplated Nickel-Iron Films
Authors: Chen Y. T.
Published: June 2020

Nickel-iron films were deposited on a copper-covered plastic substrate and annealed at 400, 600, 800, 1100, and 1200°C. The films were stripped from the substrate, and were thoroughly cleaned and dried before being annealed. Recent works [1, 2] have shown that the magnetic properties of Ni-Fe films are strongly dependent on grain size, and hence on the annealing treatment. The present work emphasizes the surface change of the film due to annealing.

The composition of the electroplated films was kept at 80% Ni, 20% Fe; the thicknesses of the annealed samples were from 5 to 10 μ. The structure of as-plated Ni-Fe film was found to be the disordered γ phase, which is fcc. All of the films were polycrystalline with no preferred crystallographic orientation. The average grain size of the as-plated films was 300 A (Fig. 1). This did not vary much within the prescribed thickness range.
In-Situ Deposition of Gold on MgO
Authors: Moorhead R. D. , Poppa Helmut
Published: June 2020

The epitaxial nucleation and growth of Au on (100) MgO substrates has recently been studied by in-situ electron microscopy methods but under poorly controlled environmental and deposition conditions using beam-cleaved thin MgO substrates. Gold on MgO has also been investigated by LEED or replica electron microscopy. Here bulk substrates cleaved in UHV were used under well controlled deposition conditions. The results of the insitu experiments and the studies on bulk substrates, however, showed appreciable differences: The bulk studies produced epitaxy at substrate temperatures as low as 100°C, whereas in the in-situ case the respective substrate temperature for epitaxy was well above 400°C; furthermore, nucleation measurements on bulk MgO seemed impurity-controlled with temperature-independent saturation densities, and strong electron irradiation of the substrate during deposition caused the appearance of an unexpected (111)-orientation.

We have repeated such studies in-situ under clean, well-controlled UHV-conditions and confirmed most of the results on bulk substrates except the nucleation kinetics.
Surface Damage in Lamellar Lunar Regolith Grains
Authors: Asunmaa S. K. , Arrhenius G.
Published: June 2020

Surface erosion and readhesion or absorption of reaction products (solid debris, gases, solidifying liquids) are the two main categories of continuous surface modifications on the submicroscopic and molecular level in the lunar regolith. The reactions on the atomistic level are induced by interactions of penetrating corpuscular radiation with the target lattice in its surface and subsurface layers. Ion implantation and electron excitation to higher energy levels into more or less shallow traps result in charge build-up. Charge redistribution is nondestructive, material redistribution by ion sputtering counteracts the erosive effects. Coherency strain along projectile paths is verified by increased susceptibility to various etching treatments. The sporadic large scale destructive effects are attributed to mechanical reactions, meteoroid impact, shock deformation, interface melting and spray of liquified silicates and metals.

Occasional extensive disintegration of grain surfaces has been documented in the course of the fossil track, studies. The objective of the present investigation is to examine the response of the surface layer of selected regolith grains to mild etchants e.g. nonreactive polar solvents such as acetone.
Observations on the Structure of Ta2O5
Authors: Kotval P. S. , Dewit C. J.
Published: June 2020

The structure of Ta2O5 has been described in the literature in several different crystallographic forms with varying unit cell lattice parameters. Earlier studies on films of Ta2O5 produced by anodization of tantalum have revealed structural features which are not consistent with the parameters of “bulk” Ta2O5 crystals

Films of Ta2O5 were prepared by anodizing a well-polished surface of pure tantalum sheet. The anodic films were floated off in distilled water, collected on grids, dried and directly examined in the electron microscope. In all cases the films were found to exhibit diffraction patterns representative of an amorphous structure. Using beam heating in the electron microscope, recrystallization of the amorphous films can be accomplished as shown in Fig. 1. As suggested by earlier work, the recrystallized regions exhibit diffraction patterns which consist of hexagonal arrays of main spots together with subsidiary rows of super lattice spots which develop as recrystallization progresses (Figs. 2a and b).
A Morophological and Crystal Structure Analysis of Particulate Rare Earth III Fluorides
Authors: Morris Coy R.
Published: June 2020

Previous work in this area (oftedal-1929, Zalkin and Templeton-1952 ) using X-ray diffraction techniques assigned primitive structural units to the rare earth trifluorides of Lanthanum, Cerium, Praseodymium, Neodymium, Ytterbium and Samarium.

The work of greatest interest in this investigation is that of Zalkin and Templeton. In their investigation they found that the 4f trifluorides from La to Nd are hexagonal while those from Sm to Lu are orthorhombic with SmF3exhibiting a dual structure of both units, depending on the temperature of formation.

Continuing the recent work of Barr, the structures of LaF3, NdF3, PrF3, SmF3and YbF3were investigated using lower chamber diffraction (LCD) which produced results appearing to conflict with the X-ray work of Zalkin and Templeton. To these authors knowledge there are no known publications dealing with the structural analysis of these five rare earth trifluorides other than the two papers cited. In addition, these works deal with X-ray determinations which, although complementary to electron diffraction, lack the microanalysis and limited innerplanar spacing analysis characteristic to ED.
Electron Microscopic Observation of Crystal Lattice Images
Authors: Komoda Tsutomu
Published: June 2020

Electron microscope images of crystal lattices have been observed by many authors since the first achievement by Menter in 1956. During these years, the optimum operating conditions with electron microscopes have been investigated for the high resolution lattice imaging. Finally minute lattice spacings around 1 Å have been resolved by several authors by using contemporary instruments. The major lattice planes with low index in crystals are almost within a range of spacing capable to be resolved by electron microscopy (1-3 Å). Therefore, the observing techniques are now essential for practical studies in the area of crystallography as well as metal physics.

Although the point to point resolution of the electron microscope is restricted due to the spherical aberration of the objective lens in addition to the diffraction, the lattice resolution is mainly limited due to the chromatic aberration under the normal illumination.
The Interpretation of Crystal Lattice Images
Authors: Cowley J. M. , Iijima Sumio
Published: June 2020

The imaging of detailed structures of crystal lattices with 3 to 4Å resolution, given the correct conditions of microscope defocus and crystal orientation and thickness, has been used by Iijima (this conference) for the study of new types of crystal structures and the defects in known structures associated with fluctuations of stoichiometry. The image intensities may be computed using n-beam dynamical diffraction theory involving several hundred beams (Fejes, this conference). However it is still important to have a suitable approximation to provide an immediate rough estimate of contrast and an evaluation of the intuitive interpretation in terms of an amplitude object.

For crystals 100 to 150Å thick containing moderately heavy atoms the phase changes of the electron wave vary by about 10 radians suggesting that the “optimum defocus” theory of amplitude contrast for thin phase objects due to Scherzer and others can not apply, although it does predict the right defocus for optimum imaging.
Energy Distribution in Electron Beams
Authors: Ohno Tamotsu
Published: June 2020

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.

The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.
Scanning Electron Microscopic Analyses of Fiber Reinforced Metals
Authors: Collins Brent R.
Published: June 2020

Recent scanning electron microscopic analyses have shown the comparison of the apparent failure modes of biaxially loaded boron reinforced aluminum composites versus uniaxial, off-axis tensile loading. Additionally, degradation of the longitudinal mechanical properties of both boron reinforced aluminum and Borsic reinforced titanium has been correlated with the growth of deleterious reaction products formed during diffusion bonding of plate and tubular specimens.

Combined loading composite theory has been based on off-axis tensile and beam specimens relying on Mohr's Circle transformation of stress to introduce designated stress ratios of ‘transverse to longitudinal stresses. Inherent in these transformations is the high amount of shear stresses applied to the orthotropic axes of the material. Figure 1 shows the fracture surface of off-axis tensile specimens depicting the variation in failure mode from filament normal tensile failure at 5° to matrix and interface shearing at 15° to matrix tensile failure at 90°.
In Situ Observation of Nucleation and Growth of Precipitates on Dislocation Lines In Al-Cu Alloy
Authors: Takahashi Noboru , Taoka Tadami
Published: June 2020

The continuous growth of precipitates was very difficult to observe directly by conventional electron microscopy, because of the size effect of a thin film used, With the JEM-1000 kV EM, similar precipitates to those in bulk specimens of Al-Cu alloy were obtained. Thus, films 0.5 μ thick or more have been found thick enough to present a Widmanstätten structure inside the electron microscope.

The specimen used was a sheet of Al-4% Cu alloy 0.1 mm thick. It was solution treated at 540°C for 3 hrs, followed by quenching. Dislocations in the specimen were introduced by scratching with a diamond scriber. The region near the scratch was thinned by jet electro-polishing and cut off as a microscope specimen, which was mounted on the heating stage combined with the goniometer. During the whole heating period of more than 2 hrs, the specimen was placed out of the electron beam for the purpose of avoiding radiation damage except at each moment of observation.
A Device for Magnification Measurement
Authors: Eades J.A. , van Dun A.
Published: June 2020

The measurement of magnification in the electron microscope is always troublesome especially when a goniometer stage is in use, since there can be wide variations from calibrated values. One elegant method (L.M.Brown, private communication) of avoiding the difficulties of standard methods would be to fit a device which displaces the specimen a small but known distance and recording the displacement by a double exposure. Such a device would obviate the need for changing the specimen and guarantee that the magnification was measured under precisely the conditions used.

Such a small displacement could be produced by any suitable transducer mounted in one of the specimen translation mechanisms. In the present case a piezoelectric crystal was used. Modern synthetic piezo electric ceramics readily give reproducible displacements in the right range for quite modest voltages (for example: Joyce and Wilson, 1969).
The Effect of Crystal Thickness on Extinction Distance
Authors: Botros K. Z. , Sheinin S. S.
Published: June 2020

Extinction distance is a parameter which, for a given material and reflection, is normally assumed to depend on accelerating voltage and the deviation from Bragg condition of the reflection concerned. The results to be presented here indicate that, under certain conditions, crystal thickness is also important in deter mining the value of the extinction distance obtained. Theoretical values of extinction distance have been determined from measurements of the peak to peak spacing in plots of diffracted beam intensity as a function of crystal thickness. All calculations were carried out by using the ‘multi-beam dynamical theory. Fig. 1 shows the variation of bright field intensity with crystal thickness for fcc cobalt when the (111) reflection is in the exact Bragg position. The systematic reflections 333…555 were taken into account, and an accelerating voltage of 150 Kv was assumed. From these results it can be seen that in thinner parts of the crystal the extinction distance is about 280Å. The results in Fig. 1 also shows that in thicker regions of the crystal the extinction distance decreases to about 180A°.
Effects of Non-Systematic Reflections on Bloch Wave Absorption Coefficients
Authors: Cann C.D. , Monk A.E.B. , Sheinin S.S.
Published: June 2020

In the dynamical theory, absorption of Bloch waves plays an important role in explaining contrast effects observed in electron microscope images of crystalline materials. Although the effects of systematic reflections on the absorption coefficients of Bloch waves have been studied, little is known about the effects of non-systematic reflections. It was with a view to investigating these effects that this work was undertaken.

The orientation chosen for this investigation is one commonly employed for obtaining good image contrast at low accelerating voltages, namely, a low order systematic reflection g, set close to its Bragg condition. Under these circumstances two Bloch waves with widely differing absorption coefficients are strongly excited. In this paper the effect of non-systematic reflections on these absorption coefficients has been studied. This has been done by determining the effect of the reflection on the (220) systematic set in Si at 150 kV.
Palygorskite, Single Crystal Electron Diffraction and Moiré Magnifications
Authors: Asunmaa S. K. , Greenslate J. , Chiappino M. L.
Published: June 2020

The objective of the electron diffraction study of palygorskite is first to obtain additional information on the crystallography and unit cell parameters and second to evaluate diffraction anomalies of a filament crystal with ribbon-like growth habit. Moiré magnification is used as an independent technique for determining the prominent lattice spacing. The reasons for the program are 1) previous observations of diffraction anomalies on elongated inclusions in a crystalline matrix rather than for isolated crystals; 2) the variations reported in unit cell parameters, a=12.6-12.9; b=18.1-18; c=5.01- 5.3A, relating to chemically bound water, inclusion water and balancing protons analogous to exchange ions in the structure R5[SigO2O](OH)2(OH2)44. 4H2O. R primarily refers to Mg2+ exchangeable for A13+ and Fe3+ in oxide ranges of Al2O3 6.82-15.44 and Fe2O3 0.87-3.8%.

Selected area electron diffraction patterns are shown in Figs. 1 and 3. A representative specimen area in Fig. 4 indicates fiber flexibility and the presence of be and ab faces coplanar with the substrate.
Ultramicrotome Thin Sectioning of Metals and Alloys
Authors: Ogura I.
Published: June 2020

Ultramicrotome thin sectioning method has many difficulties in the preparation of slices for electron microscopy on the structures of metals and alloys. Main difficulties come from the plastic deformation of the slices, and, accordingly, several studies have been made on the deformation of metals and alloys by ultramicrotomy. Through persevering researches for seeking better conditions for many years in the ultramicrotomy of metals and other inorganic materials, current state of the technique has become satisfactory to some extent as is seen in Figs. 1 and 2 which represent two examples of successful studies on metallic specimens by the use of an ultramicrotome, Type Fernandez-Moran.

Precipitation of γ-phase in Al-Ag alloy (Fig. 1) is highly accelerated by cold working before precipitation heating of the quenched alloy. High-speed straining in the ultramicrotomed thin slices of zinc single crystal (Fig. 2) has special effects on super plasticity and on recrystallization in the slices.
A Study of Dislocation Contrast for g.b = 2 and g.b = 4
Authors: Oblak J. M. , Rand W. H.
Published: June 2020

Shear of Ni3Al crystals usually takes place by the motion of paired a/2<110> dislocations. The pairs are strongly coupled by an antiphase boundary such that their separation is less than 40Å. These are imaged as single dislocations having an a<110> Burgers vector. Thus g.b equals 2 for “in contrast“ imaging with lower order reflections such as g = 111 or 200. The dislocation image contrast under such conditions is shown in Fig. 1 for varying deviations w = sξg from the Bragg orientation. This dislocation was shown by the usual method of identification to have a Burgers vector b = a [011] and, other than the screw segment A, it is mixed in character. (The accurate straightness of the screw segment is due to relaxation of the paired dislocations upon (100). For this reason its image is not representative of that for g.b = 2).
Character of Dislocations in Creep Deformed Iron Chromium Alloys
Authors: Igata N. , Miyahara K. , Taoka T. , Yoshida S.
Published: June 2020

Hitherto about creep deformed iron binary alloys, there have been few data on character of dislocations. On the dislocations in the cells, almost all dislocations were identified to be screw dislocations, but one of the remained problems is to identify the character of dislocations in subboundary. The objective of this study is to identify both dislocations in the cell boundary and in the matrix, and to interpret the behavior of dislocations in creep deformed alloys.

Used materials were Fe-6%cr alloy and creep deformed at 600°C under 4.0 Kg/mm2. The strains were within the range of steady state creep. For electron microscopy, JEM1000 and JEH200 were used.

The results show that both dislocations in the cell walls and in the matrix have mainly screw component as shown in Fig.1 and Fig.2. If the total dislocation densities are divided in to two groups, edge component and screw component , the rate of change of both components to the creep strain could be expressed as the followings.
Structure of Nickel and Nickel-Cobalt Electrodeposits
Authors: Thompson Anthony W.
Published: June 2020

Electrodeposited plates 6 mm thick were prepared from sulfamate baths by J. W. Dini and H. R. Johnson of this laboratory. The plates were pure nickel or an alloy of 57 Ni-43 Co. Tensile and fracture toughness specimens were machined from these plates; thin foils were cut parallel to the deposition plane, and also perpendicular to that plane and to the stress axis of tensile specimens. R. E. Gorniak prepared the foils by electropolishing at 3 V in an aqueous solution of 48% H3SO4, 32% H2SO4 at room temperature. Foils were examined in a Philips EM300.

As Fig. 1 shows, the grain size of the nickel was uniform and small. The true volume grain diameter d was calculated from the mean linear intercept The variations in contrast between grains in Fig. 1 persisted through large, slowly-performed changes in tilt, which suggests that a strong texture was not present.
Structure and Plastic Strain Analysis Utilizing Scanning Electron Microscopy
Authors: Schmidt Frederick E. , Lawlev Alan
Published: June 2020

‘Forming limit’ or ‘instability limit’ diagrams are particularly useful in the processing of sheet materials by deep drawing or stretch forming. The key to the development of these diagrams is a quantitative characterization of the localized state of strain at various stages throughout the forming process. A novel approach has been developed whereby the distortions of a high-resolution grid, i.e. the strain analysis, are accurately monitored by scanning electron microscopy. A concurrent characterization of the associated surface structure is obtained.

The grid for strain analysis is produced by a photoresist technique. Any practical grid master pattern may be used; the most useful shapes for the current studies are rectangles, squares, or circles with a resolution to 200 lines per inch. Photoresist emulsion is applied directly to the sheet specimen surface and air cured. The master pattern is then held secure against the emulsion by vacuum and the composite assembly exposed to ultraviolet light.
The Annealing of Neutron Irradiation-Induced Defects in Silicon Carbide
Authors: Faulkner D. , Styles R.C.
Published: June 2020

Radiation-induced changes in the macroscopic dimensions, lattice parameters, strength and thermal diffusivity of various types of silicon carbide suggest that different polytypes of this material may behave differently when subjected to a nuclear radiation field. This paper reports the existence of visible defects in post-irradiation annealed material.

RFL (Springfields) self-bonded silicon carbide was irradiated in the WR-1 organic-cooled reactor. The specimens were exposed to a fast neutron fluence of 2.2×1020nvt (E>0.18 MeV) at a temperature of 700°C. Specimens suitable for examination in the electron microscope (3m.m × 1 m.m thick discs) were subsequently annealed for 4 hrs. at temperatures up to 2000°C. The material was ground down from both sides to approximately 0.25 m.m thick and ion thinned for examination in a Hitachi HU-200E electron microscope equipped with a 40° high resolution tilting stage.
Thin Substrate Structure and Electron Scattering after EM Beam Exposure
Authors: Hill Bruce C. , Haydon Glen B.
Published: June 2020

Electron diffraction studies of organic substrates after electron beam exposure suggest that all have a common structure. As estimated by electron scattering, substrates produced from Parlodion appear to be thinner than those described by Williams et al. as being 7 AU thick.

The changes in organic materials produced by electron irradiation have been investigated by a number of researchers. Bahr et al. showed that, in general, irradiation will cause mass loss and that a considerably larger proportion of carbon than of other elements is retained in the final product. For example, an exposure of 3 × 10−2 coulombs/cm2 at 75 kV caused a 54% mass loss and 25% carbon loss in a Formvar film. Earlier investigations showed a 75% mass loss in Parlodion (nitrocellulose) films at the same dose of 70 keV electrons. We have investigated the structural changes in common substrate materials using electron diffraction studies.
Determination of the Best Emulsion for the Microscopy of Crystals
Authors: Grano David A. , Downing Kenneth H.
Published: June 2020

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.

The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.
Quantitative Analysis of Electron Diffraction Pattern and Image of Crotoxin Complex Thin Crystal
Authors: Jeng T.W. , Chiu W.
Published: June 2020

Crotoxin complex is the toxic principle in the venom of the South American rattlesnake, Crotalus durissus terrificus. This protein has two non-identical subunits and expresses its neurotoxicity via synergistic interaction. Unlike most of the neurotoxins isolated from snake venoms, this protein can have binding affinity to both post- and pre-synaptic membrane. We have reported earlier preliminary results of forming a thin crystal from this complex and of an electron diffraction pattern recorded to atomic resolution. The present paper is to discuss the space group symmetry of this protein crystal from the quantitative analysis of the electron diffraction intensities as well as of the low dose images.

The crotoxin complex crystal was embedded in 1% glucose. The electron diffraction pattern and image were recorded on Kokak Industrex AA x-ray film with 0.1 e/Å2 and 2.5 e/Å2, respectively, at room temperature. These data were scanned with a Perkin-Elmer microdensitometer Model 1010. Figure 1 shows the original and the computer processed electron diffraction pattern.
Deformation Substructure in Cemented WC-Co Materials
Authors: Kenik E. A. , Krawitz A. D. , Drake E. F.
Published: June 2020

The cemented refractory carbides represent one of the basic classes of materials used in machine cutting and rock drilling tools. These multiphase materials (a refractory carbide compact with a metallic binder phase) provide a good combination of hardness, toughness, and abrasion resistance which leads to long tool life. The present study investigates the microstructure of several cobalt-based cemented WC materials in response to different types of mechanical loading.

The materials were hot isostatically pressed sintered compacts of WC and blends of cobalt and nickel metal powders (∼17 wt %). Three blends of metal powders were used: Co-1, Co-2, and Co-3 (in increasing nickel content). During the high-temperature sintering process, the metallic binder was molten, aiding the sintering reaction and also dissolving some WC into solution. Specimens were examined in the ORNL Hitachi HU-1000 high voltage electron microscope in the undeformed state and following different conditions of mechanical treatment: low (2.1 GPa) and high (3.4 GPa) stress compressive monotonic loading, and low (1.0 GPa) and high (2.1 GPa) stress compressive cyclic loading. The high penetration power of the HVEM allowed the examination of the microstructure of the dense WC grains and thicker binder regions where the dislocation structure would be representative of that in the bulk.
Formation of <100>/{100} Dislocation Loops in Electron-Irradiated Dilute Ni-Be Alloys
Authors: Mukai T. , Mitchell T. E.
Published: June 2020

Radiation induced segregation (RIS) in alloys is becoming a common phenomenon during high temperature irradiations. Precipitate formation in solid solution alloys under irradiation (radiation induced precipitation) is a manifestation of RIS. In the present study we report the formation of <100>/{100} dislocation loops, together with the precipitation of G.P. zones on {100}, in under-saturated Ni-Be alloys during electron irradiation.

Ni-1 at.% Be and Ni-0.3 at.% Be supplied by ANL were solution-annealed and quenched into water. Electron microscope specimens were irradiated with 650keV electrons at a flux of 1-5x1019e/cm2.s using a Hitachi HU-650B high voltage electron microscope. A specimen of Ni-1 at.% Be was irradiated at 470°C for 15 min. The [001] zone-axis diffraction pattern taken after the irradiation is shown in Fig. 1(a), where evolution of streaks along <100> is evident. The streaks come from G.P. zones on {100} planes.
Measurement of Sub-Micron Sized Grains in a Powder Metallurgy Alloy
Authors: Anderson D. M. , Coyne E. J.
Published: June 2020

New concepts in airframe materials, including powder metallurgy (P/M) alloys and metal matrix composites, have been offered to aircraft manufacturers. These new materials have been suggested as alternatives to conventional ingot metallurgy products now used in airframes. Aircraft manufacturers must evaluate these materials to determine their suitability for airframe use. The stability of the small uniform grain size of prospective P/M alloys was a major concern since some of the proposed fabrication processes involved elevated temperatures. These processes typically have caused grain growth and loss of material properties in ingot materials.

A mechanically alloyed, non-heat-treatable, P/M aluminum alloy, IN-9051 is produced by the Novamet Division, MPD Technology Corporation, an Inco Company. Previous research had indicated that elevated temperatures might adversely affect this material's properties. The effect of 16 combinations of elevated temperatures (600-900° F) and times at temperature on the grain size of each of three different extrusions was measured. A similar, but abbreviated, program on sheet material rolled from these extrusions was also conducted.