bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulmonary Alveolar Microlithiasis: A Morphologic Study of Six Cases Including TEM and SEM with EDX Analysis and Immunocytochemistry
Authors: Cole S.R. , Hochholzer L. , Johnson F.B. , Knibbs D.R. 
Published: June 2020

Pulmonary alveolar microlithiasis (PAM) is a rare lung disease of unknown etiology characterized by calcified spherules which fill alveolar spaces. Although there are approximately 110 cases of PAM previously reported, only 26 have been confirmed by histologic examination. Increased interstitial fibrous tissue is seen in some cases, and some patients develop shortness of breath. However, many patients remain assymptomatic for years following the diagnosis of PAM.Six cases from the files of the Armed Forces Institute of Pathology and Hartford Hospital were studied. Light, scanning and transmission electron microscopic studies were performed as were chemical, immunocytochemical and energy dispersive x-ray analysis. Analyses suggest that they are composed in part of mucopolysaccharides and Ca3(PO4)2. Our findings indicate that microliths form initially around a cellular nidus by the deposition of calcium and phosphate salts from the extracellular matrix vesicles of surrounding cells similar to the method previously demonstrated 1n the formation of bone and psammoma bodies. PAM is not usually associated with Identifiable systemic disturbances in calcium and phosphorus metabolism.
A Stationary Solution of High-Energy Electron Reflection (HEER) for An Arbitrary Surface
Authors: MA YIQUN 
Published: June 2020

For a long time, the development of dynamical theory for HEER has been stagnated for several reasons. Although the Bloch wave method is powerful for the understanding of physical insights of electron diffraction, particularly electron transmission diffraction, it is not readily available for the simulation of various surface imperfection in electron reflection diffraction since it is basically a method for bulk materials and perfect surface. When the multislice method due to Cowley & Moodie is used for electron reflection, the “edge effects” stand firmly in the way of reaching a stationary solution for HEER. The multislice method due to Maksym & Beeby is valid only for an 2-D periodic surface.Now, a method for solving stationary solution of HEER for an arbitrary surface is available, which is called the Edge Patching method in Multislice-Only mode (the EPMO method). The analytical basis for this method can be attributed to two important characters of HEER: 1) 2-D dependence of the wave fields and 2) the Picard iteractionlike character of multislice calculation due to Cowley and Moodie in the Bragg case.
Dynamical Calculations of RHEED Intensity Evolution During MBE Growth
Authors: Peng L. -M. , Whelan M. J. 
Published: June 2020

Reflection high energy electron diffraction (RHEED) has become well established as one of the most powerful and versatile techniques for growth and surface studies of semiconductor films prepared by molecular beam epitaxy (MBE). In particular the technique of RHEED intensity oscillations has been used routinely to calibrate beam fluxes and alloys composition and to control the thicknesses of quantum wells and superlattice layers.Although several interpretations have been proposed for the strong oscillations in RHEED intensity during MBE growth, full dynamical calculations have been done only for an artificial surface consisting of a periodic array of surface steps. The enormous amount of computation involved prevents the dynamical theory being applied to a more realistic epitaxically growing system. In this paper we report a simple and practical method for calculating dynamical RHEED from MBE growing surfaces.We first consider epitaxial growth on a low-index surface. The growth is simulated by using a perfect layer growth model and a diffusive growth model.
Ultramicrotomy as a Technique for Materials Specimen Preparation
Authors: Glanvill S.R. 
Published: June 2020

This paper summarizes the application of ultramicrotomy as a specimen preparation technique for some of the Materials Science applications encountered over the past two years. Specimens 20 nm thick by hundreds of μm lateral dimension are readily prepared for electron beam analysis. Materials examined include metals, plastics, ceramics, superconductors, glassy carbons and semiconductors. We have obtain chemical and structural information from these materials using HRTEM, CBED, EDX and EELS analysis. This technique has enabled cross-sectional analysis of surfaces and interfaces of engineering materials and solid state electronic devices, as well as interdiffusion studies across adjacent layers.Samples are embedded in flat embedding moulds with Epon 812 epoxy resin / Methyl Nadic Anhydride mixture, using DY064 accelerator to promote the reaction. The embedded material is vacuum processed to remove trapped air bubbles, thereby improving the strength and sectioning qualities of the cured block. The resin mixture is cured at 60 °C for a period of 80 hr and left to equilibrate at room temperature.
Crystallographic Effect in X-Ray Microanalysis
Authors: Krishnan Kannan M. 
Published: June 2020

The interaction of a fast electron, accelerated through kilovolt potentials in an electron microscope, with a thin foil sample will produce a variety of signals that can be monitored with appropriate detectors to provide information about the crystallography, chemistry and electronic structure of trie sample. In particular, the characteristic x-ray emissions are well understood and form the basis of a simple microanalytical technique by relating the measured x-ray intensities (IA,B) to the elemental weight fractions (CA,B) using the ratio method originally proposed by Cliff and Lorimer , i.e. CA / CB = KAB * IA / IB. This formulation makes the assumption that all the possible atomic sites for the two elements (A and B) in the sample are probed with the same probability by the incident electron beam.The above assumption is not valid for crystalline samples illuminated with a parallel beam of electrons under strong dynamical diffraction conditions.
Quantitative ALCHEMI With Error Analysis
Authors: Rossouw C.J. , Turner P.S. , White T.J. , O’Connor A.J. 
Published: June 2020

The ALCHEMI technique for determining the site distribution fi of an impurity element x on host element lattice sites i is well known: Changes in x-ray emission from host atoms i and impurity x with crystal orientation ARE monitored under strong planar or axial diffraction conditions, and fi derived via a ratio method. However analysis involving count ratios (and ratios of ratios) leads to severe error amplification. Neglect of delocalization leads to further error. To overcome these inherent errors in the standard ALCHEMI method, we make the single assumption that the impurity count Nx may be written as a linear combination of the host atom counts Ni, i.e.where the coefficients αi and their errors are determined by multivariate analysis. For m separate EDX spectra and fitted parameters αi (i = 1 to v), the criterion v ≤ m must be satisfied for m - v degrees of freedom.
MMatrix Description of Rotation Around the Tilt Axes of a TEM Double-tilt Holder and its Applications to TEM
Authors: Qing Liu 
Published: June 2020

Double - tilt holder is often used to adjust the specimen orientation during the analysis of crystallology problems. The relationship between a fixed reference orthogonal coordinate, system and the tilt axes of a TEM double - tilt holder is shown in Fig. 1. When the specimen is tilted through an angle β around the second tilt axis (T2) (from β0 to β0 + β ), followed by a tilt α around the longitudinal axis (T1) (from α0 to α0 + α), the new position of a vector g isT1 and T2 are the transformation matrices related to rotations around the T1 - and T2-axes, respectively, beingKikuchi map is usually used as a ‘road map’ to adjust the specimen from one orientation to another. However, if the diffraction pattern of a zone axis [u v w] will be obtained from the original position [u0 v0 w0]where the tilt angles are α0 and β0, the tilt angles for crystal specimen orientation adjustment in the double-tilt holder can be calculated using the following two equations which deduced by the above matrices.
Determination of Residual Strains in an Al-SiCw Composite Using CBED
Authors: Rozeveld S.J. 
Published: June 2020

It is well established that large stresses may be introduced into Al-SiCw composites by thermal cycling. Due to the large difference in thermal expansion of Al and SiC, a temperature change of ~200°C is sufficient to generate dislocations in the matrix. Dislocation production does not relieve all of the stress and residual strains, which are slightly below the yield point, can remain in the matrix. Although these residual strains will influence both the aging characteristics of the matrix and mechanical response of the composite, very few experimental measurements have been made of the local residual strains in Al-SiCw composites.The purpose of this investigation was to determine the magnitude of residual strains around individual whiskers in an Al-10 vol.% SiCw composite, which was annealed at 505°C and quenched to room temperature. Convergentbeam electron diffraction (CBED) was used for this investigation since all the information in a CBED pattern originates from a small area defined by the incident probe.
Observation of Dynamic Extinction Lines in the (420) Diffraction Disks of the MgAl2O4 Spinel <100> CBED Pattern
Authors: Liu Dangrong R. 
Published: June 2020

Many people have observed dynamic extinction lines in the {200} diffraction disks of the <100> zone axis CBED (convergent beam electron diffraction) patterns of the MgAl2O4 spinel. These dark lines are manifestation of the space group of the material and can easily be explained with the Gjønnes-Moodie theory. However, in addition to the extinction lines in the {200} disks, We have also been able to observe dynamic extinction lines present in the {420} diffraction disks in the same CBED pattern.The CBED work in this work was carried out with a JEOL-2000FX microscope operated at 100.15 kV. One <100> zone axis CBED pattern is shown in Fig. 1. The dark lines are clearly shown in the {420} disks running through the two perpendicular non-principal axes, in exactly same way as the dark lines in {200} disks.One can easily explain the dynamic extinction lines in the {200} disks with the Gjønnes-Moodie theory by drawing dynamic scattering pairs oG-Ga and oH-Ha, oK-Ka and oL-La etc. in the diagram (Fig. 2).
CBED Analysis of YBa2Cu3-xAlxOy single Crystals
Authors: Kuroda K. , Matsuhata H. , Saka H. 
Published: June 2020

Single crystals of YBa2Cu30y were grown from melting mixture of yttria, barium carbonate and copper oxide contained in alumina crucibles. Crystals grew as platelets with the (001) broad surface. The use of alumina crucibles for crystal growth resulted in incorporation of aluminum to varying extents in crystals of composition YBa2Cu3-xAlx0y, x=0-0.23. Microstructural and microchemical characterization of single crystals were carried out by transmission electron microscopy along with electron dispersive x-ray analysis. Convergent beam electron diffraction (CBED) technique was used to determine crystal symmetry and evaluate symmetry-modification due to twins or local inhomogeneities. Critical voltage effects were studied with respect to oxygen stoichiometry and aluminum concentrations.The microstructures of YBa2Cu3-xAlx0y single crystals show large twin. domains (Figure la), lamellar twin structures (Figure 2a) and {110}-type tweed pattern modulations (Figure 3a) aparently depending on aluminum concentration. In selected area diffraction patterns splitting diffraction spots along the [110] direction were observed from twined structures and <110> star-shaped streakings around the diffraction spots from tweed structures.
LACBED with Quantitative Anomalous Absorption Corrections
Authors: Rossouw C.J. , Allen L.J. , Miller P.R. 
Published: June 2020

An Einstein model for thermal diffuse scattering (TDS) has enabled quantitative calculation of the absorptive potential V'(r). This allows anomalous absorption to be accounted for in LACBED contrast. Fourier coefficients Vg-h of the absorptive component from each atom α are calculated from integrals of the formwhere fα is the scattering amplitude and M(Q) the Debye-Waller factor. Integration over the Ewald sphere (dΩ) requires the momentum transfer q to have values up to 2ko (the incident beam momentum). Dynamical ‘dechannelling’ is accounted for by the terms g ≠ h. The crystal absorptive potential is obtained by coherently summing over these atomic absorptive potentials within the unit cell. Unlike the elastic potential, the absorptive potential is a strong function of incident beam energy Eo, since the range of momentum transfer q and associated solid angles dΩ change with the Ewald sphere radius.Fig. 1 shows a LACBED pattern of the zeroth order beam from Si aligned along a <001> zone axis.
Temporal and Spatial Dynamics of the Actin-Based Cytoskeleton
Authors: Lansing Taylor D. 
Published: June 2020

There has been a renaissance and revolution in the use of light microscopy in the biomedical sciences. The renaissance has been due to the importance of studying the temporal and spatial dynamics of ions, metabolites and macromolecules in living cells and tissues. The revolution has been due to the integration of developments in molecular biology, fluorescent probe chemistry, machine vision, and imaging technology. It is now possible to use the living cell as a microcuvette and to explore the chemical and molecular dynamics responsible for cellular functions.We have been investigating the formation, transport and contraction of stress fibers in Swiss 3T3 cells. Fluorescent analogs of actin, myosin, vinculin and profilin have been investigated in serum deprived cells before, during and after stimulation with thrombin. The activities of these components of the actin-based cytoskeleton have been quantified using time-lapse imaging, fluorescence redistribution after photobleaching, video-enhanced contrast and reflection interference contrast microscopy.
High-purity Ge x-ray detectors: Sensitivity factors and usefulness
Authors: Steel E. B. 
Published: June 2020

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.
Finding out more and more about less and less—fifty years of milestones in microanalysis
Authors: Wittry D.B. 
Published: June 2020

During the past half century, a wide variety of techniques of microanalysis have been developed to a practical stage and many of these are presently undergoing refinement and improvement. In fact, practically every means of bombarding a specimen with radiation and observing signals from the interaction of this radiation with the specimen has been explored, as shown in Fig. 1. Many of the techniques used in microanalysis today are based on physical principles that were known for many years. But they became practicable only with improved technology, e.g. improved vacuum systems, sources, detectors, lenses, spectrometers, signal amplifiers and computers.A "road map" of the history of microanalysis would contain some of the milestones along the way, similar to the list of significant events in the history of microscopy published in the EMSA Bulletin in Fall of 1983. My own (and highly subjective) list is given in the Table. It is not surprising that many of the key figures contributors on this list have been previous recipients of the EMSA Distinguished Scientist Award (names printed in bold face).
Structural and electronic properties of defects in semiconductors
Authors: Batstone J.L. 
Published: June 2020

The development of growth techniques such as metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy during the last fifteen years has resulted in the growth of high quality epitaxial semiconductor thin films for the semiconductor device industry. The III-V and II-VI semiconductors exhibit a wide range of fundamental band gap energies, enabling the fabrication of sophisticated optoelectronic devices such as lasers and electroluminescent displays. However, the radiative efficiency of such devices is strongly affected by the presence of optically and electrically active defects within the epitaxial layer; thus an understanding of factors influencing the defect densities is required.Extended defects such as dislocations, twins, stacking faults and grain boundaries can occur during epitaxial growth to relieve the misfit strain that builds up. Such defects can nucleate either at surfaces or thin film/substrate interfaces and the growth and nucleation events can be determined by in situ transmission electron microscopy (TEM).
Automated electron tomography: from data collection to image processing
Authors: Liu Weiping , Fung Jennifer , de Ruijter W.J. , Chen Hans , Sedat John W. , Agard David A. 
Published: June 2020

Electron tomography is a technique where many projections of an object are collected from the transmission electron microscope (TEM), and are then used to reconstruct the object in its entirety, allowing internal structure to be viewed. As vital as is the 3-D structural information and with no other 3-D imaging technique to compete in its resolution range, electron tomography of amorphous structures has been exercised only sporadically over the last ten years. Its general lack of popularity can be attributed to the tediousness of the entire process starting from the data collection, image processing for reconstruction, and extending to the 3-D image analysis. We have been investing effort to automate all aspects of electron tomography. Our systems of data collection and tomographic image processing will be briefly described.To date, we have developed a second generation automated data collection system based on an SGI workstation (Fig. 1) (The previous version used a micro VAX). The computer takes full control of the microscope operations with its graphical menu driven environment. This is made possible by the direct digital recording of images using the CCD camera.
New applications of near-field optical storage
Authors: Kino G. S. , Hayashi S. , Ichimura I. 
Published: June 2020

Some time ago, we described a new type of near-field imaging system using the Solid Immersion Lens. A confocal microscope using this principle has demonstrated sub-100 nm resolution with visible light. In this paper, we will describe how this device is being applied to increasing the density of optical storage in CD ROMs and magneto-optical storage systems.The SIL is placed between the objective and the disk. As illustrated in Fig. 1(a), if the SIL is in the form of a hemisphere, rays enter it along its radii and converge at its center. If the refractive index of the SIL is n, the wavelength in this material is reduced by 1/n and consequently increases the effective NA of the objective lens by the refractive index n and decreases the spot size by 1/n. With this configuration, we were able to obtain good quality images of a grating with 100 nm gaps and strip widths.
High-resolution Transmission Electron Microscopy of dislocations in intermetallic compounds
Authors: Mills M.J. 
Published: June 2020

The fine structure of dislocations plays a critical role in determining the macroscopic mechanical behavior Intermetallic compounds. Many of the technologically important characteristics of these compounds, an example their strength at high temperatures, appear to be determined by intricate details of dislocation stucture at the atomic level. High resolution transmission electron microscopy (HREM) offers the etential to obtain structural information at this level by observing these line defects in an "end-on" configuration.Samples of HREM images of several important dislocation types in Ni3Al and TiAl are shown in Figures through 3. Each of these particular dislocation types (i.e. Burgers vectors and line directions) tend to be longly favored in these compounds, indicating that along these line directions the dislocations are likely have either low mobility or low energy.
Advanced microscopy—the new high-resolution zone-plate microscope at the advanced light source in Berkeley
Authors: Meyer-Ilse W. , Medecki H. , Magowan C , Balhorn R. , Moronne M. , Attwood D. 
Published: June 2020

A new x-ray microscope (XM-1) has been installed at the Advanced Light Source in Berkeley. This transmission microscope uses zone-plates for a resolution exceeding visible light microscopies. Samples can be as thick as 10 microns, for wet or dry specimens. These features make x-ray microscopy a valuable complement to other advanced techniques.There are two types of x-ray microscopes, scanning and conventional (imaging) microscopes. The scanning type minimizes radiation dose to the sample and is convenient for high resolution use of fluorescent labels; however, it requires a spatially coherent x-ray source and as a result involves long exposure times. The conventional type provides a higher potential for ultimate resolution as there is no scanning stage needed, and it can operate with an incoherent light source. It therefore has a shorter exposure time, but does require a higher radiation dose due to lens inefficiencies. The new XM-1 is of the second type. Its optical layout is very similar to the Gottingen x-ray microscope operated at the BESSY facility in Berlin, Germany.
Chemical sensitivity of convergent beam electron diffraction on the stoichiometry of GaN
Authors: Liliental-Weber Zuzanna , Kisielowski Christian , Washburn Jack 
Published: June 2020

III-V nitride thin film growth has attracted considerable attention because it now seems feasible to engineer semiconductor band gaps between 2.1 and 6.2 eV. One of the challenges coming with this development is related to the fact that structural perfection seems not to correlate directly with optical properties such as the emission of blue-green or UV light in GaN. In order to better understand this material High Resolution Transmission Electron Microscopy (HREM) and Convergent Beam Electron Diffraction (CBED) experiments were used to study structural defects in GaN thin films. Experiments were performed with a Topcon 002B and ARM operating at 200 and 800 KeV, respectively, and were guided by image simulations. Results of parallel luminescence studies will be published elsewhere.Plan-view micrographs of GaN grown on the (0001) basal plane of A12O3 with a lattice mismatch of 14% show small angle grain boundaries which divide the layer into large subgrains of about 800 nm diameter. Other defects visible in the plan-view micrographs are threading dislocations and planar defects lying parallel to the {1010} planes of the GaN.