bluuebunny/crossref_metadata_2025_split huggingface dataset:
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 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 crystalsFilms 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).
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.
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.