bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Ion Pumps for Electron Microscopes
Authors: Maliakal J. C.
Published: June 2020

Recently there has been much interest generated in improving the vacuum systems of Electron Microscopes and Electron Microprobes. Specimen contamination has been reported to be partly due to interaction of the electron beam and hydrocarbon molecules from poorly trapped oil diffusion pumps, organic gaskets, grease used on, gaskets, etc.

Condensible vapors from the above contaminants in the specimen chamber also increase the contamination rate on the specimen. This paper reviews the methods available for an improved vacuum system for Electron microscope and other analytical instruments using oil free ionic vacuum pumps.
High Voltage Electron Microscopy of Muscle
Authors: Rice Robert V. , Lally J. S.
Published: June 2020

Several structures have been proposed to account for the appearance of Z and M-lines seen in thin sections of striated muscle. The high penetrating power of 800,000 to 1,000,000 volt electrons coupled with stereology offers a unique opportunity to resolve the complicated fine structure of Z and M-lines. In addition use has been made of the recently developed extraction and reconstitution of Z and M-lines (Stromer, Hartshorne, Mueller, and Rice, J. Cell Biol., 40, 167, 1969). Removal of portions of these structures helps to eliminate confusion due to adjacent structures.
A New 1000kv Electron Microscope
Authors: Williams J.L. , Heathcote K. , Greer E.J.
Published: June 2020

High Voltage Electron Microscope already offers exciting experimental possibilities to Biologists and Materials Scientists because the increased specimen thickness allows direct observation of three dimensional structure and dynamic experiments on effectively bulk specimens. This microscope is designed to give maximum accessibility and space in the specimen region for the special stages which are required. At the same time it provides an ease of operation similar to a conventional instrument.
New Type High Voltage Generator
Authors: Ohta S. , Watanabe M. , Nakamura O.
Published: June 2020

A high voltage generator has been developed with an extremely small ripple component by incorporating resistors in series in the filament transformer of the center-tapped Cockcroft Walton circuit. The rating of the prototype is 500 kV, and incorporates the following features, (See Fig. 1)

1.

The generator itself is perfectly symmetrical with respect to the output circuit.

2.

Stray capacitance (Cs) between the primary and secondary windings of the filament transformer can be reduced to negligible proportions.
Compact Magnetic Lenses for HV Electron Microscopy
Authors: Strojnik A.
Published: June 2020

The number of ampere turns NI at a given Bsat is the major factor in determining the size of conventional magnetic lenses in HV microscopes. As a consequence of increased size of the winding and hence of the length of magnetic circuit, the iron cross section has to be made large. This leads to large overall dimensions, high power consumption and difficulties in cooling and handling.
Electron Irradiation Effects on the Growth and Structure of Vapor Deposited Films
Authors: Chopra K. L.
Published: June 2020

This review talk will deal with the effects of electron irradiation on nucleation, growth, microstructure, epitaxy and, in some cases, metastabilization of new and abnormal crystal structures of vapor deposited films. The effects depend on the substrate and film materials, energy and current density (and its spatial variation) of the electron beam, and further on whether irradiation is carried out before, during, or after film deposition. In view of the large number of variable and uncertain parameters involved, it is not possible to make general predictions of the effects. However, several examples will be discussed to illustrate the various effects.
Low-Pressure Oxidation of Thin Single Crystal Films of Copper
Authors: Rowe Anne P. , Brockway L. O.
Published: June 2020

As an extension of previous work in this laboratory on the reaction of oxygen with thin single crystal films of copper, the reaction has been studied at an oxygen pressure of 3 x 10-6 torr at 525°C. The films were grown by evaporation onto (100) NaCl substrates and subsequently annealed to produce (100) copper films about 800 Å thick with wide complex stacking faults and 50 to 150 Å high surface terraces.
Transmission Electron Microscopic Investigation of Pt-Si Thin Films
Authors: Anderson Ronald M. , Dash Somnath
Published: June 2020

Recently, studies of platinum-silicon ohmic contacts in semiconductor device metallurgy have prompted us to make an investigation into the nature of the reaction between silicon and platinum. We confined ourselves to Pt deposition temperatures, annealing temperatures, and thicknesses that were germane to the production of ohmic contacts.

Transmission electron microscopy, selected area electron diffraction, and reflection electron diffraction analysis, coordinated with x-ray diffraction studies, were performed and allowed us to make the following observations.
Scanning Electron Beam Instrument for Photo Resist Exposure
Authors: Miyauchi S. , Tanaka K. , Russ J. C.
Published: June 2020

With the recent commercial introduction of the scanning electron microscope there has been considerable interest in the possibility of modifying this instrument for the exposure of photo resists in producing integrated circuits for the electronics industry. These modifications include beam blanking and scan programming. Because not all of the requirements of this type apparatus are consistent with the best design of a scanning electron microscope, JEOL has designed and is now introducing an instrument intended specifically for this purpose, the JEBX-2B.
Numerical Analysis of the Multiple Beam Equations for Electron Diffraction
Authors: Bell W. L. , Thomas G.
Published: June 2020

The differential equations of the n-beam dynamical theory of electron diffraction are, neglecting absorption and common phases,
Simple Identification of Electron Diffraction Ring Patterns
Authors: Nohr Carolyn , Ayres Ann
Published: June 2020

Texts on electron diffraction recommend that the camera constant of the electron microscope be determine d by calibration with a standard crystalline specimen, using the equation
Thermal Recovery Processes in Explosion-Shocked Nickel
Authors: Trueb Lucien F.
Published: June 2020

Electron microscopy has been used extensivley to investigate annealing processes in metals, but most of the work refers to cold-worked materials. Only a limited amount of information has been published concerning the microstructural changes occurring during annealing of explosively shockloaded metals. It is known, however, that the small extent of permanent deformation and the very high densities of lattice defects induced by shock-loading of metals, particularly at high explosive pressures, results in thermal recovery processes which are quite different from those occurring in conventionally deformed metals. The present study was concerned with the microstructure of pure polycrystalline nickel after explosive shock treatment at 70, 320 and 1000 kb and subsequent heat treatments between 600 and 780°C.
The Surface Structure of Mouse Heart Mitochondrial Membranes
Authors: Kreutziger G. Oscar
Published: June 2020

The surface substructure of mouse heart mitochondrial membranes has been studied by freeze-etching. Eight different surfaces have been observed and identified. These are the sarcoplasmic interface, the outer and inner surfaces of the outer membrane, the lipid faces of the outer membrane, the intermembrane and matrix surface of the inner envelope, and the matrix interface.

Freeze-etch replicas from glutaraldehyde fixed and glycerine cryoprotected mouse heart muscle were produced in a modified Bullivant-type simple freeze-etch device. The replicas were cleaned with “Clorox” and examined unsupported on 300 mesh grids in a Siemens Elimskop 1A.
Bacteriophages Associated with Turkey Coecums in Bluecomb-Infected and Healthy Birds
Authors: Ritchie A. E.
Published: June 2020

The cause of bluecomb disease in turkeys is unknown. Filtration of infective intestinal contents suggests a viral origin. To date, it has not been possible to isolate the etiologic agent in various cell cultures. The purpose of this work was to characterize as many virus-like entities as were recognizable in intestines of both healthy and bluecomb-infected turkeys. By a comparison of the viral populations it was hoped that some insight might be gained into the cause of this disease. Studies of turkey hemorraghic enteritis by Gross and Moore (Avian Dis. 11: 296-307, 1967) have suggested that a bacteriophage-host cell interaction may bear some causal relationship to that disease.
Prevalence of Bernhard Virus-Like Particles in Clones of BHK-21 Cells
Authors: Vander Weide Gretchen C. , Ma Booe II , Shipman Charles
Published: June 2020

The BHK-21 line of Syrian hamster fibroblasts is used widely for research on viruses and on the neoplastic transformation of cells in vitro. Bernhard and Tournier were the first to describe a virus-like particle in BHK-21 clone 13 (BHK-21/13) cells. Subsequent studies have confirmed the presence of Bernhard particles in BHK-21/C13/TC6/A, BHK-21F and BHK-21/13S. Despite the detection of such particles in several clones of BHK-21, and cells derived from spontaneous or induced hamster tumors, the widespread occurrence of the Bernhard particle has not received general recognition by many virologists. It is the purpose of this communication to document the presence and distribution of this virus-like particle in all clones of BHK-21 studied to date and to alert investigators to the prevalence of this particle.
Surface Structure of the Spores of Glugea Weissenbergi
Authors: Vernick Sanford H. , Tousimis Anastasios , Sprague Victor
Published: June 2020

Recent electron microscope studies have greatly expanded our knowledge of the structure of the Microsporida, particularly of the developing and mature spore. Since these studies involved mainly sectioned material, they have revealed much internal detail of the spores but relatively little surface detail. This report concerns observations on the spore surface by means of the transmission electron microscope.
The Composition of an Insect Sensory Nerve, The Cercal Nerve of the House Cricket Acheta Domesticus
Authors: Edwards John S.
Published: June 2020

This report concerns aspects of cell number and diversity arising from a developmental study of an insect sensory nerve. The cereal nerve arises in the abdominal cercus, and terminates in the last abdominal ganglion, and forms part of the well known startle reflex.

Tissues were fixed in 2% paraformaldehyde, 0.5% glutaraldehyde, Millonig phosphate buffer, pH 7.3 sectioned on a Sorvall Porter Blum MT2, stained with Reynold lead citrate and uranium acetate, and examined with an RCA EMU3G.
The Dermal Glands of Rhodnius Prolixus
Authors: Lai-Fook J. E.
Published: June 2020

Dermal glands are epidermal derivatives which are reported to secrete either the cement layer, which is the outermost layer of the epicuticle or some component of the moulting fluid which digests the endocuticle. The secretions do not show well-defined staining reactions and therefore they have not been positively identified. This has contributed to another difficulty, namely, that of determining the time of secretory activity. This description of the fine structure of the developing glands in Rhodnius was undertaken to determine the time of activity, with a view to investigating their function.
Ultrastructure of Granules Passing Through Frog Oocyte Nuclear Pores
Authors: Cole Madison B.
Published: June 2020

Ovaries of Rana pipiens larvae were fixed in glutaraldehyde, post-fixed in osmium tetroxide, and embedded in epon. Thin sections of oocytes were routinely stained using methanolic uranyl acetate followed by lead citrate.

The granule, designated M1, found in the primary oocytes is considered to pass through the nuclear pores by virtue of 1) its location in the nucleoplasm in close proximity to the nuclear envelope, 2) its contact with the nuclear pores, 3) its presence in aggregates in the perinuclear cytoplasm and A) its similarity to granules referred to by a number of authors (1-4) as material passing through nuclear pores.
Interreceptor Contacts in Olfactory Mucosa of Prog and Turtle
Authors: Graziadei P. P. C. , Pierantoni R. L.
Published: June 2020

Besides the mechanical role of supporting elements, supporting cells in the vertebrates olfactory mucosa have been attributed the role of secretion and isolation of olfactory receptors. The role of isolating elements has been presently investigated and the data obtained prove this role should be revised. With the transmission electron microscope sections perpendicular and parallel to the surface of the olfactory mucosa were studied. In perpendicular sections it has been observed that receptors (r) are on occasion in mutual direct contact at the level of the junctional complex (Fig. 1). Furthermore, along their dendritic process they come close together both along large areas or through specific armlike (a) processes. (Fig. 2). In sections parallel to the surface the receptors arrange themselves in annular interconnected patterns. Each receptor, moreover, extends short protrusions (the same armlike processes (arrow) as seen in perpendicular sections) to the neighboring neurons (Fig. 3).
Path of Fracture Planes Along Membrane Surfaces in Frozen-Etched Tissue
Authors: Leak L. V.
Published: June 2020

The course of the fracture plane through frozen tissue may very often follow surfaces of membranes for long distances before cross fractures are made, exposing the interior of cells and cellular organelles. From studies on frozen-etched cellular membranes Moor and Muhlethaler suggested that fractures occur along external surfaces of membranes, while Branton proposed that the fracture process splits the membrane in half, revealing either of the two internal membrane faces. Our earlier studies suggested that most of the en face views of membranes represented fractures along the membrane surface. The present study combines the technique of freeze-etching with those of conventional electron microscopy in an effort to provide additional information on the precise nature and path of the fracture plane along membrane surfaces.
Ultrastructural White Matter Changes in Acute Experimental Hydrocephalus in the Rhesus Monkey
Authors: Clark Ronald G. , McGrath Philip P. , Milhorat Thomas H. , Ewell John B.
Published: June 2020

Recently Milhorat developed a surgical technique for producing obstructive hydrocephalus in the rhesus monkey. With this technique, pronounced ventricular enlargement occurred within a few hours following obstruction of the 4th ventricle. Employing this method, the authors have been studying brain sections from hydrocephalic monkeys by light microscopy. Of interest is the finding that, within 48 hours following obstruction of the ventricular system, large areas in the periventricular white matter appeared pale in myelin stains (Fig. 1). These regions were lateral to the temporal and occipital horns of the lateral ventricles. Using various lipid stains, no demyelinization could be detected in these areas. It was, therefore, decided to investigate this finding by electron microscopy in order to determine whether or not there were detectable ultrastructural changes in the white matter.
Ultrastructural Lesions of Liver and Heart Induced by Cobalt
Authors: Sekhri K.K. , Alexander C.S. , Nagasawa H.T. , Derr R.F.
Published: June 2020

Several reports have appeared in the literature implicating cobalt in the etiology of the so called "Beer-drinker's cardiomyopathy". Cobalt is also known to induce skeletal and cardiac neoplasms in the rat and "cobalt heart disease" in the rabbit. To elucidate the effects of cobalt on the ultrastructure of liver and heart, six rabbits were injected subcutaneously with 2.5% of cobaltous chloride in doses of 2.5 mg/kg/24 hour for nine days and 25 mg/kg/24 hour for an additional four days. Two rabbits which served as controls received an equivalent dose of 2.2% sodium chloride solution. Tissues were fixed in 2.5% cacodylate buffered glutaraldehyde, post-fixed in 2% osmic acid and embedded in Epon-araldite. Sections were stained with lead citrate and uranyl acetate and examined under an RCA EMU4 microscope.
Linear Arrays of Helical Polyribosomes in Cells Exposed to Antitumor Drug Vincristine Sulfate
Authors: Krishan Awtar
Published: June 2020

Earle's L-929 fibroblasts treated with mitosis-arresting but sub-lethal doses of vinblastine sulfate (VLB) show hypertrophy of the granular endoplasmic reticulum and annulate lamellae. Exposure of the cells to heavier doses of vincristine sulfate (VCR), a VLB-related drug, leads to the accumulation of large amounts of helical polyribosomes, Golgi membranes and crystals in the cytoplasm. In many of these cells a large number of helical polyribosomes are arranged in prominent linear rows, some of which may be up to 5 micrometers in length. Figure 1 shows a large array of helical polyribosomes near a crystalline mass (CRS) in an Earle's L-929 fibroblast exposed to VCR (5ϒ/ml.) for 3 hours At a higher magnification, as seen in figure 2, the helical polyribosomes are seen arranged in parallel rows. In favorably cut sections, a prominent backbone like "stalk" of finely granular material, measuring approximately 300Å in width is seen in close association with the linear rows of helical polyribosomes.
The Infection of Cells by Bullet-Shaped Viruses
Authors: Murphy Frederick A. , Harrison Alyne K. , Whitfield Sylvia G.
Published: June 2020

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.
Freeze-Fracture Replication of Frozen Outer Segments of Rat Retinal Rods
Authors: Leeson Thomas S. , Leeson C. Roland
Published: June 2020

Numerous previous studies of outer segments of retinal receptors have demonstrated a complex internal structure of a series of transversely orientated membranous lamellae, discs, or saccules. In cones, these lamellae probably are invaginations of the covering plasma membrane. In rods, however, they appear to be isolated and separate discs although some authors report interconnections and some continuities with the surface near the base of the outer segment, i.e. toward the inner segment. In some species, variations have been reported, such as longitudinally orientated lamellae and lamellar whorls. In cross section, the discs or saccules show one or more incisures. The saccules probably contain photolabile pigment, with resulting potentials after dipole formation during bleaching of pigment. Continuity between the lamina of rod saccules and extracellular space may be necessary for the detection of dipoles, although such continuity usually is not found by electron microscopy. Particles on the membranes have been found by low angle X-ray diffraction, by low temperature electron microscopy and by freeze-etching techniques.
Modification of the Electron Microscope for Investigation of Fully Hydrated Biological Specimens
Authors: Moretz R. C. , Parsons D. F.
Published: June 2020

Short lifetime or total absence of electron diffraction of ordered biological specimens is an indication that the specimen undergoes extensive molecular structural damage in the electron microscope. The specimen damage is due to the interaction of the electron beam (40-100 kV) with the specimen and the total removal of water from the structure by vacuum drying. The lower percentage of inelastic scattering at 1 MeV makes it possible to minimize the beam damage to the specimen. The elimination of vacuum drying by modification of the electron microscope is expected to allow more meaningful investigations of biological specimens at 100 kV until 1 MeV electron microscopes become more readily available. One modification, two-film microchambers, has been explored for both biological and non-biological studies.
Scanning Device Combined with Conventional Electron Miscroscope
Authors: Koike H. , Ueno K. , Suzuki M.
Published: June 2020

A scanning image observation device has been developed for use in conjunction with the JEM-100B Electron Microscope, thereby enabling the microscope to function as a high resolution scanning EM in addition to its basic function as a conventioanl high resolution electron microscope. As a result, it is possible to observe three different types of image of the same specimen area; viz, secondary electron images, transmission scanning images and conventional transmission electron microscope images. It is also possible to detect strays and obsorbed electrons, so that, the combined instrument provides a means for obtaining a wealth of information about the specimen.
A High-Resolution Scanning Microscope for Surface Studies
Authors: Hart R. K.
Published: June 2020

There are a growing number of applications for high brightness electron optical systems which operate in non-contaminating “clean” residual gas atmospheres. These criteria are especially important if one wishes to look at, and characterize, surfaces for the purpose of following their behavior under rigorously-controlled conditions. Besides the obvious improvements to be gained in resolution and longer exposure to the electron beam, scanning electron microscopy can now be combined with other powerful techniques. These techniques include low energy electron diffraction (LEED), Auger electron spectroscopy (AES) and field emission retarding potential (FERP) studies of surface work functions.

At one end of the electron optical column shown in Figure 1, which is only 20 cm long from source to specimen, a field emitting tungsten tip is used as the electron source, while at the other end of the column a four grid LEED/AES system has been affixed to the objective lens housing. The remainder of the column consists of a cylindrical magnetic lens, stigmator, and scanning coils. The residual gas pressure in the column during operation is <10-9 torr.
A New Color Display System for Scanning Transmission Microscopes
Authors: Crewe A. V. , Beck V.
Published: June 2020

The most important aspect of the use of the scanning principle in high resolution transmission microscopy is that one can obtain separate electrical signals corresponding to the number of elastically and inelastically scattered electrons. A new display system has been constructed to take advantage of this quantitative information. This system has two independent functions: to display the picture produced by a scanning electron microscope and to interface the microscope to a computer.

The color display system itself consists of a PEP-400 video-graphics storage terminal, a modified Zenith TV, and a video digital interface. The storage terminal is used as a scan converter and as storage for up to four pictures. It is possible to selectively erase portions of pictures stored in the terminal and then write new data into these regions. The storage terminal is thus a sort of random access memory. Information stored in the terminal will remain in storage for several days independent of whether the terminal's power is left on; however, a region can only be viewed for about five minutes, as the process of reading out a picture slowly destroys the picture.
A Calibration Method Usable in the Production of Phase Plates for High Resolution Electron Microscopy
Authors: Thon F. , Willasch D.
Published: June 2020

It is well known that phase contrast in electron microscopy is normally due to the phase shift γ introduced by defocusing and spherical aberration of the objective lens. It is given by Scherzer's formula (2) :

(1)

where γ is the electron wavelength, Csthe spherical aberration coefficient, θ the diffraction angle and Δz the defocus value.

However, in this way, only sections out of the spatial frequency spectrum contained in the abject are transferred to the image. In order to transmit the whole frequency spectrum, it has been proposed that a phase shifting plate is inserted into the back focal plane of the objective lens.
Applications of a Micro-Recording Device
Authors: Mueller K.-H. , Rindfleisch V.
Published: June 2020

As described earlier the ELMISKOP 101 can be used as a very versatile micro-recorder. For this the cross-over of the electron gun is demagnified by the condensor system and the objective lens of the microscope (maximum demagnification 5000 x) Using the magnetic deflection system the minute probe can be shifted within the back focal plane of the objective lens. In this way contamination traces may be produced on a thin carbon foil.

It is possible to drive the probe by an external electronic control unit with different programs. The control unit consists of a scanning generator to write gratings, point patterns and concentric circles to be used as calibration objects for the electron microscope, a flying spot scanner for the production of arbitrary halftone pictures and a unit with attached paper tape recorder.
Spatial Resolution of X-ray Analysis with Solid and Thin Specimens
Authors: Russ John C.
Published: June 2020

The attachment of xray spectrometers, both wavelength and energy dispersive, to both scanning and transmission electron microscopes has provided the microscopist with the possibility of obtaining elemental analysis of features in the specimen that he can observe in the image. However, the volume of the specimen that emits xrays is in all cases larger than the image point he can observe in the highest resolution image with the microscope, and so he must use judgement to determine just how large a region is being analyzed.

With a solid specimen in the SEM the situation is much like the conventional microprobe. Figure 1 shows the typical drop-shaped capture volume many times larger than the incident beam, and much deeper than the secondary electron source.
Energy Dispersion X-ray Analysis: Absorption and Background Effects Observed in the TEM
Authors: Duff R. H. , Bender S. L.
Published: June 2020

The need to obtain quantitative data from an energy dispersive X-ray spectrometer following its successful adaptation to a transmission electron microscope requires a knowledge of the absorption properties of X-rays in thin films in order to utilize the X-ray intensities generated and to select an optinum excitation potential. Information relating specimen thickness and accelerating potential to signal intensity for pure substances is necessary before analyses of more complicated systems with varying thicknesses can be undertaken.

For this purpose, gold films of varying thickness (measured by using the Fizeau fringes in an interference microscope) were thermally evaporated onto freshly cleaved rock salt substrates, floated off on water and picked up on nickel grids.
Techniques for Examining Void Distribution in Ion Bombarded Metals
Authors: Wolff U. E. , Lauritzen T. , Rosenbaum H. S.
Published: June 2020

Ion bombardment is a convenient and economical means for simulating the damage produced in metals due to fast neutron irradiation. Unlike that produced by neutrons, however, the damage caused by ion bombardment is not homogeneously distributed throughout the volume of the metal since ions penetrate metallic specimens only a short distance. Moreover, the number of displaced atoms is a sensitive function of the kinetic energy of the bombarding ions as well as the depth within the target material (specimen). Therefore materials which have been subjected to ion bombardment require careful analysis of the spatial distribution of the damage before meaningful inferences can be made.

The experimental material for this study was Type-304 stainless steel sheet, approximately 100 μm thick, which was bombarded in a cyclotron with 12 MeV deuterons. Irradiation time and temperature were the principal variables. Because of the small size of the voids produced and the shallow damage zone, techniques of transmission electron microscopy (TEM) are most commonly used for void examination. In the present work we compare two alternative approaches to the problem of characterizing the spatial distribution of damage within such specimens.
Residual Gas Reactions in the Electron Microscope: IV. A Factor in Radiation Damage
Authors: Hartman Richard E. , Hartman Roberta S.
Published: June 2020

The common assumption that in the electron microscope there is a minimum, irreducible, dose-dependent damage to the specimen caused by inelastic scattering of electrons implies that such damage results from a one - step process. We now have evidence that this assumption is open to serious question.
Computer Processing of Electron Micrographs
Authors: Ball Frances L. , Harris W. W. , Welton T. A.
Published: June 2020

In view of the modest success reported elsewhere in this meeting with computer processing of simulated micrographs to compensate for image defects such as those caused by astigmatism, defocus, and spherical aberration, we have attempted to apply these ideas to processing of real micrographs. Carbon films originally deposited on mica were used as samples. Ferritin molecules were deposited for use primarily as fiducial markers and through-focus series were made at an electronic magnification of 200,000 X, using a Siemens Elmiskop la at 80 keV, modified for a 2.2 mm objective. A C. W. French type PF pointed filament was used. Contamination was not detectable. In some cases further photographic enlargement of 4 X has been made to allow a better match to the available scanning equipment. The scanner used was an Optronics “Photoscan,” capable of a 25μ raster, and placing the density values directly on IBM-compatible magnetic tape.
Reconstruction of Three Dimensional Structures from Electron Micrographs: The Equivalence of Two Methods
Authors: Lake James A.
Published: June 2020

A transmission electron micrograph is to a good degree of approximation a projection of a three dimensional structure. Provided that a sufficient number of projections are available, it is possible to reconstruct a three dimensional structure which is consistent with the projections. Among the methods which have been proposed for generating a three dimensional structure from projections, two methods alone produce single, unique structures which are consistent, in a least squares sense, with the projections from which they are derived.

The first of these was demonstrated by DeRosier and Klug in a reconstruction of the tail of the bacteriophage T4. Their technique is illustrated in figure 1. A three dimensional structure, represented by the duck, is Fourier transformed to yield a three dimensional Fourier transform. (Fourier transformation is a mathematical operation readily performed on a digital computer.) An inverse Fourier transformation exists and the Fourier transform of the duck may be inversely transformed to recreate the three dimensional duck structure.
Computational Correction of Aberrations in Electron Microscopy
Authors: Welton T. A.
Published: June 2020

A previously reported technique for computer production and simulated optical filtration of synthetic electron micrographs has been extended to the study of a promising prescription for reconstruction of an object from a micrograph rendered imperfect by aberrations, diffraction, and noise. If the general nature of the object is known and a quantitative theory is available for image formation by the instrument in question, then a non-linear least squares adjustment of the unknown parameters (orientation, translation, and structural alternatives such as heavy atom substitutions) can in principle be used to obtain a clean (not necessarily accurate) picture. In practice, a linear procedure is much simpler, and in an electron micrograph with phase contrast, a simple combination of Abbe image theory with two-dimensional information theory leads to a simple linear filtering prescription.
The Formation of Crystallographically Aligned a/3 <112> Dislocations in Ni3Al
Authors: Giamei A. F. , Oblak J. M. , Kear B. H. , Rand W. H.
Published: June 2020

Although intrinsic stacking faults have been observed in cold rolled polycrystalline Ni3Al, the terminating superlattice partial dislocations have not been identified. Since superlattice intrinsic stacking faults (S-ISF) can be formed by the glide of a/3 <112> partials, we have recently suggested specific interactions between paired a/2 <110> slip dislocations which could result in the formation of such partials. In the present study the partial dislocations and associated stacking faults formed during multiple slip in Ni3Al are identified. These partials have a/3 <112> Burgers vectors and lie parallel to <110> directions. The latter is explained in terms of the relaxation of the superlattice partials along cube planes.

Thin foils were prepared from sheets of directionally solidified columnar-grained Ni3Al that had been rolled (~ 5% reduction) along the common <100> direction. While the familiar long straight a/2 <110> type screw dislocation pairs were observed in some grains, extended stacking faults were present in most areas of the foil where multiple slip had occurred, Figure 1.
S.E.M.-T.E.M. Image Comparison
Authors: Greene G. M. , Sprys J. W.
Published: June 2020

The present study demonstrates that fracture surfaces appear strikingly different when observed in the transmission electron microscope by replication and in the scanning electron microscope by backscattering and secondary emission. It is important to know what form these differences take because of the limitations of each instrument. Replication is useful for study of surfaces too large for insertion into the S.E.M. and for resolution of fine detail at high magnification with the T.E.M. Scanning microscopy reduces sample preparation time and allows large sections of the actual surface to be viewed.

In the present investigation various modes of the S.E.M. along with the transmission mode in the T.E.M. were used to study one area of a fatigue surface of a low carbon steel. Following transmission study of a platinum carbon replica in the T.E.M. and S.E.M. the replica was coated with a gold layer approximately 200A° in thickness to improve electron emission.
Electrodeposition in Magnetic Fields
Authors: Dash J. , King W. W.
Published: June 2020

A previous report described the influence of magnetic fields (B) on the process of electrothinning of metals. Stirring effects observed at the cathodes of the cells during these experiments suggested that applied B might affect significant changes in the characteristics of electrodeposits. This was investigated for the deposition of Cu from CuSo4 - saturated H2O solutions. The substrates used for deposition were double, 3mm diameter Cu grids. Experiments with the grids suspended at several different orientations with respect to the applied B have shown that significant changes in the morphology of the deposits can be produced. For example, with a Cu grid suspended horizontally in the electrolyte and B = 7.4 k G applied parallel to the plane of the grid, the original square shape of the grid openings is retained to a much greater extent (Fig. 1a) in comparison to the results obtained without applied B (Fig. 1b).
Examination of Surveyor III Moonlander Support Strut by TEM
Authors: Buvinger E. A.
Published: June 2020

The Surveyor III spacecraft was landed on the lunar surface in the Ocean of Storms on April 20, 1967. Thirty-one months later the crew of Apollo 12 removed several items of interest from the moonlander and returned them to Earth. Among these was a length of polished, unpainted aluminum tubing which had been part of the support strut for the Radar Altitude Doppler Velocity Sensor (RADVS). At the Lunar Receiving Laboratory the tubing was cut into sections for study by various investigators. Two sections (C and E) were examined by the author to determine the type and degree of microscopic damage which the tubing had incurred during its exposure to the lunar environment. Specifically, the surface was examined for evidence of ion bombardment by solar wind and for micro-meteorite impact damage.

Replication electron microscopy was used to perform the study. The replicating plastic was elvanol (polyvinyl alcohol), and the replicas were shadowed at 10 or 25 degrees with Pt-C.
Characterization of Rare-Earth Fluoride Anti-Stokes Phosphors by Scanning arid Transmission Electron Microscopy
Authors: Low N. M. P. , Brosselard L. E.
Published: June 2020

There has been considerable interest over the past several years in materials capable of converting infrared radiation to visible light by means of sequential excitation in two or more steps. Several rare-earth trifluorides (LaF3, YF3, GdF3, and LuF3) containing a small amount of other trivalent rare-earth ions (Yb3+ and Er3+, or Ho3+, or Tm3+) have been found to exhibit such phenomenon. The methods of preparation of these rare-earth fluorides in the crystalline solid form generally involve a co-precipitation process and a subsequent solid state reaction at elevated temperatures. This investigation was undertaken to examine the morphological features of both the precipitated and the thermally treated fluoride powders by both transmission and scanning electron microscopy.

Rare-earth oxides of stoichiometric composition were dissolved in nitric acid and the mixed rare-earth fluoride was then coprecipitated out as fine granules by the addition of excess hydrofluoric acid. The precipitated rare-earth fluorides were washed with water, separated from the aqueous solution, and oven-dried.
SEM Analysis of Transistors Damaged by Microwave Energy
Authors: Christou A. , Retter R. E.
Published: June 2020

In this paper we discuss the importance of visual microscopic data as it pertains to recognizing the characteristic traits of semiconductor microwave failures. Failure modes associated with a current and voltage overstress have been identified. However, characteristic traits of transistor failures during high microwave irradiation are at present undetermined. The analysis is focused on a thorough microscopic inspection of the surface topography of the microelectronic device after being opened. The temperature of the chip during RF irradiation is the significant key to determining the cause of semiconductor failures. The approximate temperature variations which occur during RF irradiation can be estimated after a microscopic investigation of damaged areas. The SEM was used for the analysis because of its large depth of field (Figure 1). In addition, the specimen-current amplifier in the SEM was used to amplify the electrical current which flows through a specimen when the electron probe strikes its surface. The specimen current amplifier method of obtaining a signal is especially valuable to transistor investigations where a bias is applied and the conduction current collected (Figure 2}
Lithium Precipitation in Silicon
Authors: Magee T. J. , Comer J. J. , Kimerling L. C.
Published: June 2020

Direct observation of precipitates has been previously reported in silicon diffused with phosphorus, arsenic, copper, aluminum, and lithium. The precipitates observed in these studies varied in shape from square, rod-like, hexagonal or irregular platelets, often exhibiting no preferred alignment, to nearly spherical regions of varying concentration and localization, depending upon the initial defect density and crystalline perfection. In the present study it was desired to examine the precipitation process in lithium diffused silicon in terms of the induced defect morphology and diffusion time. To accomplish this end, n-type polished silicon wafers of (111) orientation were coated with mineral oil containing a suspension of lithium. The samples were subsequently annealed for variable times at 450°(C) in a helium atmosphere. The faces were then cleaned ultrasonically in a solution of methyl alcohol and distilled water. After appropriate chemical-mechanical polishing, the samples were subjected to a 2-hour anneal at 600°(C) to insure homogenization.
Electron Microscopy of Porous Materials—The Structure of a Commercial Alumina Catalyst Support
Authors: Faulkner D. , Sagert N. H. , Sexton E. E. , Styles R. C.
Published: June 2020

Many practical catalysts consist of a metal supported on a stable material. The activity of such a system depends not only on the chemical properties of the metal and support, but also on certain physical properties of the support such as surface area, pore volume and pore size distribution. Indirect information on the pore structure of the support material can be obtained from low-temperature nitrogen adsorption experiments, but a more direct technique for obtaining this information is to examine the material in the electron microscope.

The material chosen for this study was a high porosity alumina obtained from Englehard. The pore size distribution as supplied by the manufacturer indicated 0.24 cc of pores/g in the range 0-100Å, and 0.16 cc/g > 100Å. Figure 1 is a scanning electron micrograph of the surface of the material. Although no great detail can be resolved, the surface is obviously uneven, and gives the impression of being somewhat fibrous in texture. Figure 2 is a transmission electron micrograph of the same material. This sample was prepared by crushing the material and dispersing the particles on a carbon substrate.
Electron Microscopic Evidence of Authigcnic Clay Minerals in the Gulf of Mexico
Authors: McKce Thomas R. , Whitehouse U. Grant
Published: June 2020

Authigenic mineral formation is one consequence of the geochemlcal model of a steady-state ocean-atmosphere. Many examples of authigenic clay minerals might be expected, however the distinction between authigenic and detritial clay minerals is not well defined. It is extremely difficult in most cases to distinguish between the two while running a standard mineraloglcal analysis. Consequently the formation or reconstitutlon of clay minerals in the world oceans has remained a matter of much consideration.

Weaver points out that many of the clay minerals occuring in recent marine environments which are identified as being definitely authigenic are Fe-rich. These include glauconlte, nontronite, chamosite, montmorillonite and chlorite. The majority of these have been found in the Pacific Ocean with montmorillonite being the most abundant. Norin reported authigenic illitic mica in coarse-grained sediments from the Tyrrhenian Sea. Garrels has compiled a phase diagram which indicates that under the conditions normally found in seawater, kaolinite and K-mica can exist in mutual equilibrium growing from a solution derived from K-feldspar and quartz.
Fatigue Properties of Clad Metals
Authors: Turk C. , Santala T. , Jean D.
Published: June 2020

Theoretical and experimental investigations have shown that a propagating crack can interact with an internal interface significantly affecting the bulk properties of the composite. Because only limited work has been reported regarding the effect of a laminate structure on fatigue life, Texas Instruments Conflex 326 material, which consists of 10 volume-%. OFHC copper metallurgically bonded on both sides of 80 volume-% AISI 1065 steel, was selected for fatigue experiments to study the behavior of the crack at the interface.

All laminates were roll bonded, reduced to gage and annealed at 1375°F for one hour. Monolithic steel was obtained for testing by dissolving the copper cladding in a concentrated nitric acid. Milled fatigue and tensile specimens were austenitized for one hour at 1500-1550°F and water quenched. Tempering specimens were tempered at temperatures from 200°F to 1100°F. Figure 1 shows the microstructure of the core material for samples tempered at 200°F, 600°F, and 1000°F.
The Effects of Interfacial Torque on the Geometry of Twin-Grain Boundary Intersections
Authors: Horylev R. J. , Murr L. E.
Published: June 2020

The characterization of a grain boundary in a thin film section by transmission electron microscopy has been described previously. In addition, the geometrical configurations resulting from interfacial torque at twin-grain boundary intersections have been described by the use of the electron microscope. There have been, however, no attempts to systematically study the effect of interfacial torque on the geometry of twin-grain boundary intersections in thin metal films. Neither have there been any attempts to systematically study the interrelationships of the degrees of freedom characterizing a grain boundary in a three-dimensional thin section in the electron microscope. The present work describes the relationship of grain boundary misorientation, inclination (θ), and asymmetry (Φ) to relative interfacial free energy; and the dependence of these parameters on relative interfacial torque at twin-grain boundary intersections observed by transmission electron microscopy.
Growth and Structure of Silicon Films Evaporated Onto Rock Salt
Authors: Shimaoka G. , Chang S. C.
Published: June 2020

It is well known that the evaporation of oxide free films of silicon is difficult in a conventional vacuum (10-4-l0-5 Torr), and because of alloy formation with heater elements conventional refractory metal heaters (e.g., Ta, Mo, W) cannot be used for the evaporation of silicon. Recent studies of silicon films evaporated onto a silicon substrate in ultrahlgh vacuum and using uncontaminated evaporation source have demonstrated that their structure and epitaxy are greatly influenced by several experimental parameters, such as ambient pressure during deposition, purity of evaporation source, deposition rate, and substrate surface conditions as well as substrate temperature. The purpose of, the present study is to investigate growth and structure of silicon thin films evaporated onto a clean rock salt substrate surface prepared in ultrahlgh vacuum and to find optimum epitaxial growth condition.
Preliminary Comparative Studies of the Ultrastructure of Reconstituted Normal and Aminonucleoside-Nephrotic Rat Skin Collagen
Authors: Watson John H. L. , Bartlett Paul D.
Published: June 2020

Both the rate and the extent of reactivity of carbonyl groups of α-collagen fractions of acetic acid extracted skin collagen of aminonucleoside-nephrotic (AN) rats are reduced in comparison with the reactivity of such groups in similar fractions prepared from normal rat skin. Since collagen fibrillogenesis is dependent upon the participation of such groups in the formation of both intra- and intermolecular cross-linkages, differences might be expected to be demonstrable between the ultrastructure of collagen fibrils reconstituted from solubilized preparations of skin collagen from the normal and the AN rats. To investigate this possibility, skin collagen from both normal and AN rats was prepared essentially as described by Gross and Kirk. The collagen was solubilized in each case in 0.2M acetic acid and then dialized against 0.2M NaCl for four days at 4°C. Collagen fibrils reconstituted in this manner were negatively stained for electron microscopy with 1 percent phosphotungstic acid adjusted to pH with NaOH.
Ultrastructure of Aspergillus Fumigatus Spores: Conidiation and Maturation
Authors: Ghiorse William C. , Edwards Mercedes R.
Published: June 2020

Ultrastructural aspects of developing conidia and phialides of fungi have been investigated. The present report deals with an electron microscope study of developing and maturing conidia in A. fumigatus.

The strain selected sporulated profusely on potato dextrose agar at 37 C. Observations on conidiation and on immature spores were carried out on 24 or 48 hr cultures. Aerial conidiophores were fixed in situ by flooding the culture with cacodylate buffered glutaraldehyde containing 0.01 M calcium chloride and 0.3% Tween 80. Fixation proceeded under vacuum, at it C, overnight. Portions of mycelium were selected under a dissecting microscope while being washed in buffer. Osmication, dehydration, and embedding in Epon were by standard procedures, except for a prolonged infiltration time. For observations on mature conidia, 2 to 21 day cultures were used. Spores were washed from the surface of the agar with the fixative solution and collected by centrifugation. Fixation continued in a manner similar to that used for the aerial conidiophores.