bluuebunny/crossref_metadata_2025_split huggingface dataset:
TEM of Conducting Filament in Nb-Nb2O5-Bi Switching Glass Structure
Authors: Anderson Ronald M. 
Published: June 2020

There has been considerable interest in the electronic component industry concerning the switching phenomena exhibited by certain glasses. Switching is observed in thin Nb2O5 glass sandwiched between Niobium and Bismuth conductors. A typical device vertical structure is shown in Fig. 1. Transmission electron microscopic techniques were used to consider structural aspects of the Nb-Nb2O5-Bi devices. First, the microstructure of the conducting filament was unknown and secondly, optical and scanning electron microscopy showed the top of the one micron wide filament to be shaped like a volcano and situated in the center of a large six to ten micron wide crater in the Bi top conductor with no apparent metallic contact to the Bi. This last point is illustrated in the optical micrograph, Fig. 2a, and the SEM photo, Fig. 2b.The Bi metallurgy to filament conducting scheme was immediately obvious in TEM. The floor of the six to ten micron wide large crater was covered with ∼500Å thick Bi up to the lip of a minor crater, within which thinner, ∼200Å thick, Bi was continuous up to the filament.
Fundamental Research into Thin Films in a Developing Country
Authors: Eades J.A. , Grünbaum E. 
Published: June 2020

In the last decade and a half, thin film research, particularly research into problems associated with epitaxy, has developed from a simple empirical process of determining the conditions for epitaxy into a complex analytical and experimental study of the nucleation and growth process on the one hand and a technology of very great importance on the other. During this period the thin films group of the University of Chile has studied the epitaxy of metals on metal and insulating substrates. The development of the group, one of the first research groups in physics to be established in the country, has parallelled the increasing complexity of the field.The elaborate techniques and equipment now needed for research into thin films may be illustrated by considering the plant and facilities of this group as characteristic of a good system for the controlled deposition and study of thin films.
Interpretation of Electrostatic Properties of Lunar Regolith
Authors: Asunmaa S. K. , Arrhenius G. 
Published: June 2020

Evidence of a net surface charge on lunar regolith components and of their persistent internal polarization was discussed in a recent paper with references to charge significance for particle aggregation (Figs. 1-5); regolith dynamics; lunar dust storms; track density evaluation and albedo. The electret character observed appears to correlate with the irradiation and thermal history of the regolith. Electron microscopy provides direct evidence of microstructural features that promote internal polarization and preservation of charge.The lunar dielectrics do not contain molecular dipoles. Elongated grains in the fines fraction tend to align in the direction of the field at sites of sufficient mobility (Figs. 3, 4, 5), suggestive of electric moments similar to those of polymeric materials whose molecular dipoles aggregate to form supramolecular dipoles. The number density and the distribution of free charge carriers obtained from the various ion implantations in the surface and subsurface layers (depending on particle energies) are heterogeneous and subject to charge redistribution in an applied field.
High Quality Wide Field Imaging with JEM-100B
Authors: Shirota K. , Yanaka T. 
Published: June 2020

Due to the field aberrations, mainly curvature of image field, astigmatism and field chromatic aberration, it is difficult to obtain a photograph which is of high quality from the center to the corners of the plate. But the aberrations vary greatly with the construction of lens system and the excitation modes of the lenses. This paper describes the possibility of high quality wide field imaging with the aberration minimised JEM-100B.The width of over fringes Dsf caused by the curvature of image field and astigmatism, and the blur ΔF caused by the field chromatic aberration, both in the meridian plane, are given by the following equations based on Glaser's Blenden Freien System:λ: wavelength, λ,K: constant, Ca...Fa,Cv,CF: aberration coefficient, xo: distance from the axis, α: angle of electron beam to the axis.
Image Theory and Image Processing
Authors: Welton T. A. 
Published: June 2020

The fundamental problem of electron microscopy is the maximal extraction of object information from a noisy image. The noise-free image of course represents the object only with considerable distortion of several types. The electron microscope fails to transmit all spatial frequencies equally, and it can seriously distort local retardation and absorption values. In addition, a sample may have an essentially 3-dimensional structure compressed into a 2-dimensional display. We attempt to give a reasonably comprehensive theory of these effects, with a view to formulating a useful computational procedure for producing the best possible reconstruction of a sample from the available image data.As the starting point, a theoretically sound treatment has been devised to replace the standard Abbe theory which, although enormously useful, has some difficulties. The wave equation is solved for a retarding and absorbing sample, immersed in a focussing field, on the reasonably valid assumption that the sample consists of a set of spherically symmetric elements (atoms).
Spatial Frequencies in Electron Images of Negatively Stained Protein
Authors: Flskin A. Max 
Published: June 2020

Phase-noise which occurs in defocused Images of a negative stain layer has been extensively characterized, but usually in terms of an optical transform as averaged over fields of stain layer of an order of a tenth of a micron. We have found that adjacent fields of stain layer, if ranging from 100 to 200 A, frequently exhibit different spatial frequencies. We describe here the use of an optical autocorrelational technique by which to compare the spatial frequencies in images of negatively stained glutamic dehydrogenase (GDH) to those present in equivalent areas in the image of the surrounding stain layer.Autocorrelational functions were recorded photographically as described previously, using the procedure developed by Meyer-Eppler and Darius. Several series of micrographs, each providing a through-focus set of data, were made of GDH negatively stained with 1% uranyl acetate on thin carbon substrates. Each micrograph was enlarged either by three or five steps of magnification with contrast enhancement.
New Aspects in the Design of Electron Optical Magnification Systems
Authors: Andersen Willem H.J. 
Published: June 2020

Electron microscope design, and particularly the design of the imaging system, has reached a high degree of perfection. Present objective lenses perform up to their theoretical limit, while the whole imaging system, consisting of three or four lenses, provides very wide ranges of magnification and diffraction camera length with virtually no distortion of the image. Evolution of the electron microscope in to a routine research tool in which objects of steadily increasing thickness are investigated, has made it necessary for the designer to pay special attention to the chromatic aberrations of the magnification system (as distinct from the chromatic aberration of the objective lens). These chromatic aberrations cause edge un-sharpness of the image due to electrons which have suffered energy losses in the object.There exist two kinds of chromatic aberration of the magnification system; the chromatic change of magnification, characterized by the coefficient Cm, and the chromatic change of rotation given by Cp.
Solid-Cadmium-Induced Cracking of Ti-6Al-4V Alloy
Authors: Meyn D. A. 
Published: June 2020

Solid cadmium-induced cracking (SCIC) has been observed in titanium alloys and steels, and is a solid state analogue to liquid metal embrittlement. It is potentially inimical to titanium alloy utilization because titanium fasteners are cadmium plated to prevent galling, and aircraft structural parts of titanium alloys are usually assembled with cadmium plated steel fasteners.Unnotched cantilever bend bars of Ti-6A1-4V solution treated and aged to 150,000 psi yield strength were loaded at 300°F (148°C) to 85,000 psi and 185,000 psi nominal bending stress in air with cadmium, steel, copper, or zinc pressed into the tension surface. After 100-200 hours, specimens in contact with cadmium cracked 0.025-in. to 0.040-in., regardless of the nominal bending stress. Identical cracking occurred in vacuum annealed (dehydrogenated) specimens. None of the other contact metals caused cracking. Figure 1 shows the fracture surface of a cadmium-cracked specimen. The “thumbnail” cracks consisted mainly of intergranular cracking and transgranular cleavage (Fig. 2).
Intensive Staining by Immersion Method
Authors: Nemeth Faye 
Published: June 2020

Spurr Low-Viscosity embedding media provides superior infiltration of tissues, however difficulty in obtaining intense stains with lead and uranyl solutions by the flotation methods led to investigation of immersion procedures. The reported method permits staining of both surfaces of the section, is easy to perform, does not take too long a time, and routinely gives intensely stained specimens with a minimum of precipitation.Method: A stender dish is prepared for use by placing a smaller Petrie dish inside of the stender dish and pouring Indicarb (Fisher Scientific Co.) around the periphery. The Petrie dish provides a platform for staining, and the Indicarb absorbs the CO2. The stender dish should have a tight cover.Staining dishes are prepared by using Lucite bars with drilled holes as suggested by Feldman and described by Pease Serological plates with deep wells, at least 3 to 4 mm. in depth can also be used to provide support for the paraffin.
Molecular Imaging in High Electric Fields
Authors: Panitz J. A. 
Published: June 2020

For the past thirty years, attempts have been made to use the field-electron emission microscope (FEEM), and the field-ion microscope (FIM) to image organic molecules. These attempts were inspired by the simplicity of the techniques and the potential for achieving high image contrast, magnification, and resolution. Since both microscopies rely on direct point projection for imaging, there is no need for electron-lens systems or devices to minimize specimen vibration. As a result, both techniques offer the hope of achieving high quality molecular images with a minimum of effort.In the early 1950's the FEEM was the only microscope which had demonstrated a magnification of 106 at an image resolution better than 2nm. Since it had already been used to image the diffusion of monomolecular films on clean metal surfaces, there was growing optimism that individual organic molecules could be imaged as well. In 1951, striking FEEM patterns of flaventhrene and copper-phthalocyanine were obtained which displayed the known symmetry of each molecule (two-fold and four-fold, respectively). Unfortunately, the success of these experiments was relatively shortlived.
Investigations of Defective β-NiAl by Transmission Electron Microscopy
Authors: Liu H. C. , Chang E. , Mitchell T. E. 
Published: June 2020

The β-NiAl phase, which is an ordered B2 structure, covers a wide range of compositions extending from ∼46 at.% Ni to ∼60 at.% Ni. For non-stoichiometric β-NiAl, studies (1,2) have shown that, for compositions below 50 at.% Ni, structural vacancies are introduced on the Ni sublattice (denoted as VNi), but for compositions above 50 at.% Ni,excess Ni atoms replace A1 atoms on the A1 sublattice (denoted as NiAl). In this work, defect structures in compositions of 45, 45.5, 46, 47, 50, 55, 58 and 60 at.% Ni were studied by electron diffraction techniques in a Siemens 102 TEM.Figs. 1 and 2 show selected area diffraction patterns at the exact [011] and [001] zone axes respectively.
Preliminary Electron Microscopic Study of Thermal-Shock-Resistant Ceramic-Metal Composites
Authors: Lauf R. J. , Morgan C. S. 
Published: June 2020

Ceramic-metal composites, or cermets, are used for a variety of applications. In general, the ceramic phase provides hardness or wear resistance while a continuous metal phase acts as a binder and provides toughness. The alumina-based cermets described here are unique in that the metallic phase (platinum) is discontinuous and constitutes only about 1 to 2 vol % of the structure. This material was developed to serve as a high-temperature electrical insulator under conditions of severe thermal shock. Because of the small grain sizes involved, electron microscopy was used to study the relation between properties and process variables as well as to better understand the mechanism of thermal shock resistance.Platinum was intimately mixed with alumina powder by precipitation from a PtCl4 solution followed by drying. The resulting powder mixture was hot-pressed in a graphite die at 1610°C for 15 min under 69 MPa (10,000 psi) pressure. Cermets produced from Alcoa A-17 alumina powder had a final grain size of 15 ± 4 μm, while Fisher Scientific reagent-grade alumina resulted in a grain size of 4 ± 1 μm. The platinum particles ranged from 0.2 to 1.0 μm in diameter. Thermal shock resistance was tested by heating the cermet to 520°C and quenching in hot water. Cermets that were gastight after 15 quench cycles were considered acceptable. Thermal shock resistance was improved by heating the as-pressed pellet to 1630°C and air cooling.
TEM Studies of Crystalline Minerals in Mt. St. Helens Ash
Authors: Rice L. , Dash J. 
Published: June 2020

Mount St. Helens ash is a pumaceous, pyroclastic material which has been dispersed in varying amounts over most of the Pacific Northwest on a number of occasions during 1980, including the catastrophic eruption of May 18 1980. Samples have been collected and examined from several sites between the crater itself and northwestern Oregon from March 20, 1980 through October 17, 1980. Ejected material consists of both older mountain and new particles. Tephra composition varies in proportions of glass and glass-coated minerals with length of plume travel time. Portland area fallout has ranged from coarse, steel gray, low in glass on June 12, 1980 (travel time two hours) to fine, talcy, brownish gray, high in glass on May 25, 1980 (travel time six to eight hours).Crystalline, sub-micron sized particles of the ash are being studied by the selected-area electron diffraction technique with the TEM in an effort to determine the nature of the mineral content of the ash. The particles are deposited on carbon-coated grids containing small pieces of evaporated gold film for determination of accurate camera constants. Several plagioclase feldspar minerals (70-75% of the mineral fraction for Cascade volcanoes) have been identified from random samples of the atmospheric fallout.
A SEM and EDS Study of Manganese Nodules From the Northwest Atlantic
Authors: Berry V.K. , Addy S.K. 
Published: June 2020

In a recent study of micronodules from the red clay province on the Abyssal Hills of Northwest Atlantic the micronodules were generally found to be bo-tryoidal clusters of concentric “ compact balls” fused in a coarse grained friable “Porous Cement.” It is believed that the compact balls which have higher Mn content than Fe, were formed by direct precipitation of ferromanganese oxide from the sea water at the sediment water interface and later joined with each other by a porous cement containing higher Fe and clay content. In the present studies two groups of nodule samples were used to compare their morphology and chemistry with the micronodule samples studied earlier. The samples from one group were collected from the Abyssal Hills-the red clay area and the second group from the Bermuda High-the foraminiferal clay area.The location and the depths of the four samples studied here are (1)28°46.2'N, 60°20.5'W, 5359 meters, (2)27°01.5'N, 58°49.8'W, 5087 meters, (3)31°16.07N, 67°37.99'W, 4590 meters and (4)same as (3) but different location in the vicinity. The nodule samples varied in size from ½” to 3” in diameter. The sample pieces were mounted on a carbon planchet with silver paste and sputtered with ∼200Å of AU/Pd, before transferring to the microscope. Both the outside surface of the nodules and the inside surface (after cutting open with a sharp blade) were examined in JEOL JSM-35 SEM fitted with Nuclear Semiconductor Si (Li) x-ray detector and Tracor Northern NS-880 Analysis System. The microscope was operated at 25kV acc. voltage in the secondary electron emission mode. The x-ray spectra were taken in 0-10 keV range with total count time of 100 sec.
Some Observations on Core Edge Fine Structure and Orientation Dependent Effects in Inelastic Electron Scattering
Authors: Grunes L. A. , Leapman R. D. , Ray A. B. , Silcox J. 
Published: June 2020

In this paper we review experiments carried out at Cornell University in recent years concerning fine structure in core edges and effects in cross sections that relate to orientation dependent effects on inelastic electron scattering in crystals. The experiments are primarily of an exploratory character but do demonstrate how inelastic scattering could be of value in studies of oxidation in transition metals. They also indicate how characteristics such as the directionality of a final state Π* orbital or peaks in the final density-of-states appear in the spectra. Finally, at low energy losses the orientation dependence can be related to anisotropic effects in the optical constants.The experiments were carried out in a Hitachi HU-llA-Wien electron spectrometer system described previously. For present purposes, the role of the electron microscope is to provide a sophisticated electron optical bench which, using small angle scattering geometry, can explore scattering angles below 3x10-4 radians at angular resolutions of 10-5 radians (corresponding to a wave vector change of k0θ≃0.0015 Å-1).
Electron Energy Loss Spectroscopy of Surfaces and Interfaces
Authors: Krivanek O. L. 
Published: June 2020

The structure of bulk surfaces can be studied by reflection electron microscopy and the structure of interfaces in thin foils by TEM. Both methods are capable of nearly atomic-level resolution. This paper explores whether the structural information can be supplemented with chemical and electronic information by the use of electron energy loss spectroscopy.Energy loss spectra from the surface of bulk Be have been obtained at 35kV primary energy by Klein, and spectra of the Si surface at 14.2kV have been obtained by Schilling, who also demonstrated that the relative strength of the volume and the surface plasmon can be altered by changing the reflection geometry.Fig. 1 contains two energy loss spectra obtained in surface reflection from (100) Si at 100kV in a standard TEM (Philips 400) with a magnetic sector energy analyzer (Gatan 607), and a diagram showing the geometry of the incident beam and the beam admitted into the spectrometer relative to the surface.
Digital Image Processing of High Resolution 500KV Micrographs
Authors: Kirkland E.J. , Siegel B.M. , Uyeda N. , Fujiyoshi Y. 
Published: June 2020

The predominate linear components of a defocus series of bright field phase contrast electron micrographs of a thin specimen may be represented in Fourier space as;(1)If there are m micrographs in the series then are m dimensional vectors, each component of which represents one micrograph. is the Fourier transform of the recorded defocus series and is the random noise content of is an mx2 matrix representing the transfer functions of the microscope (including spherical aberration, defocus, and partial coherence). is a two component vector representing the two components (real and imaginary) of the ideal unaberrated phase contrast image, is a two dimensional spatial frequency vector in the image plane.
Electron Diffraction Applied to the Study of the Structure of (110) Tilt Boundaries in Fe-3% Si
Authors: Hall E. L. , Briant C. L. , Walter J. L. 
Published: June 2020

It has become clear in recent years that both low-angle and high-angle grain boundaries can be described in terms of periodic structures. It has also been shown that much useful information concerning the structure of grain boundaries can be obtained by a combination of imaging and electron diffraction in the TEM. In the present study, these techniques are applied to the investigation of grain boundaries in high-purity Fe-3% Si. This material was chosen since very little work has been done to date on the structure of boundaries in bcc materials, and because it was possible to produce nearly pure (110) tilt boundaries with a wide range of angular misorientation in this material by a series of rolling and annealing treatments.The geometry of electron diffraction effects associated with grain boundaries has been extensively described in the literature. In the case of a boundary which is parallel to the electron beam and which has a periodicity present with a direction and a spacing P, a row of spots will occur in reciprocal space at each matrix reflection with a direction and a spacing 1/P.
Thin Foil Viewing Screens and On-Line Computer as HVEM Focusing Aids
Authors: Pawley J. , Neuberger D. , Hanrahan P. 
Published: June 2020

Because 1 MeV electrons have a mm range in the A1 viewing screen substrate, the screen image is dim and of low resolution/contrast (CTF). This makes it difficult to focus and, at higher magnification, to stigmate. This paper describes improvements both to the normal viewing screen and to a low light level TV viewing system as part of an ongoing improvement program.Improvements in viewing screen performance have been handicapped by the lack of a simple method of measuring screen CTF. In the only careful study, Camps and Cosslett used the microscope lenses to form a spot on the screen and this was then scanned in a fan-shaped raster. The raster was photographed through the viewing window and the negative then analyzed at different line spacings with a microdensitometer. Unfortunately, this study only analyzed the effect of phosphor type and thickness and did not consider the thickness and atomic number of the substrate.
Polymer Morphology Revealed by Staining Techniques
Authors: Reimschuessel A. C. , Kramer V. 
Published: June 2020

Staining techniques can be used for either the identification of different polymers or for the differentiation of specific morphological domains within a given polymer. To reveal morphological features in nylon 6, we choose a technique based upon diffusion of the staining agent into accessible regions of the polymer.When a crystallizable polymer - such as nylon 6 - is cooled from the melt, lamellae form by chainfolding of the crystallizing long chain macromolecules. The regions between adjacent lamellae represent the less ordered amorphous domains into which stain can diffuse. In this process the lamellae will be “outlined” by the dense stain, giving rise to contrast comparable to that obtained by “negative” staining techniques.If the cooling of the polymer melt proceeds relatively slowly - as in molding operations - the lamellae are usually arranged in a radial manner. This morphology is referred to as spherulitic.