bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advances in Parallel-Detection EELS
Authors: Krivanek O.L. , Dellby N. , Gubbens A.J. , Kundmann M.K. , Leber M.L. , Ray D.A. , Truong K.V. 
Published: June 2020

Parallel-detection electron energy-loss spectrometers (PEELS) now routinely provide spectra in which the main source of noise is the statistical fluctuation in the number of arriving electrons (i.e., they have DQE > 0.5), achieve an energy resolution which is more than 90% limited by the electron microscope gun, and are fairly easy to operate. They have pushed the minimum detectable mass (MDM) obtainable by PEELS close to the single atom level, and have improved the minimum detectable mass fraction (MDF) so that it is now comparable or better than MDF detectable by EDXS even for elements as heavy as Fe. The attainable energy resolution is now 0.3-0.5 eV on a routine basis when the spectrometer is mounted on a cold field-emission gun (S)TEM operating at 100 kV (Fig. 1). This impressive progress has opened up an important question: where next?Our answer is three-fold: towards greater integration of EELS with other techniques of electron microscopy, towards new applications of the technique, and towards more quantitative and yet more user-friendly analysis of the results.
Interfacing a Personal Computer to an Analog Scanning Electron Microscope for Storing Images on Optical Disks
Authors: Ransick Mark H. , Barklay Chadwick D. 
Published: June 2020

Most manufacturers of scanning electron microscopes (SEM) now offer models that display an image digitally. This holds many advantages, including the ability to store the image on a disk and perform image analysis on the sample. Most SEMs in service, however, produce only an analog video output; they do not have the ability to digitize the image. Film is the only method of storing images.Consequentially, film is a significant portion of every microscopy laboratory’s budget. Completely eliminating the use of film from use is not practical. There will always be the need to examine a hard copy of the image; many programs require duplicate copies of each image generated; and it is sound practice to keep a copy of each image on file. By archiving digital images to an inexpensive media, the amount of film used or the time devoted to processing negatives can be greatly reduced.By using personal computers (PCs)s, with a digitizing board and analog to digital (A/D) board, it is possible to construct a relatively low cost digitizing system for any SEM.
Performance of a Wien-Filter Energy Analyzer Installed in a TEM for EELS
Authors: Terauchi Masami , Kuzuo Ryuichi , Satou Futami , Tanaka Michiyoshi , Tsuno Katsushige , Ohyama Junichi 
Published: June 2020

We have been developing a new instrument for high resolution EELS with a spacial resolution of 100nm, a momentum resolution of 0.02A-1 and an energy resolution of 10meV. It is composed of a JEM-1200EX electron microscope - the basic component - , a field emission gun and two Wien filters ( an energy- monochrometer and analyzer) with a retardation lens and an acceleration lens.The shape of the Wien filter was designed to produce the Wien condition E=v × B (E:electric field, B:magnetic field, v:velocity of electrons ) not only in the filter but also in the fringing field regions and to form a stigmatic focus. We reported a preliminary result on energy-loss spectra of Aluminum obtained by using only the analyzer at two different retarding potentials of Uo=2000V and 600V. We believed that the result was taken at the stigmatic focus condition, though we could not understand the reason why such spectra were not obtained at Uo < 600V.
Particulate Magnetic Media Contamination: Large Defects
Authors: Ackerman Evelyn R. , Kimmel Gerald 
Published: June 2020

Participate magnetic media is widely used throughout the computer industry for data storage. Particle contamination is a major source for head crashes in magnetic disk drives. Bit size, track width and flying heights are decreasing because of the demands for greater storage density. As a result, the interfacial phenomena between the head and the disk are becoming critical. Particles generated during the operation of a magnetic disk drive or introduced through the defects in the filtering system, can cause a Head/Disk Interference (HDI) and/or result in a total system failure due to a head crash.Interaction between the head and the particle becomes responsible for HDI or head crashes. The HDI occur either from the head impacting and shattering the particle as shown in Figure 1 or the particle is dragged across the disk surface by the head as shown in Figure 2. The particle, marked by the arrow, in Figure 2 has been pushed into the substrate.
Measurement of subscellular calcium distribution in cardiac muscle in the presence of caffeine and elevated extracellular calcium
Authors: Hurley B. J. , Cantino M. E. 
Published: June 2020

Calcium is thought to play a major role in the activation of mammalian cardiac muscle. Several investigators have utilized Electron Probe X-ray Microanalysis (EPMA) to study the role of calcium in myocardial contraction. The purpose of this study is to measure subcellular elemental concentrations in rat papillary muscle under the influence of caffeine or elevated extracellular calcium. Of particular interest is the concentration of calcium in the junctional sarcoplasmic reticulum (jSR) under these conditions.Male Sprague-Dawley rats weighing approximately 300 g were anesthetized using I.P. Na-pentabarbitol injection. The hearts were carefully removed and back-perfused with a modified Tyrodes solution via cannulation of the aorta. The wall of the right ventricle was cut away revealing the papillary muscles. The tendon and wall ends of the papillary muscle were then sutured and the muscle was carefully cut out of the heart. The papillary muscle was then placed on the freezing device holder and the suture tied to a fixed post and tension transducer post, as shown in Figure 1.
Concentration determination of chromatin in unstained resin-embedded sections by means of Z-contrast in STEM
Authors: Haider M. , Bohrmann B. 
Published: June 2020

The technique of Z-contrast in STEM offers the possibility to determine the local concentration of macromolecules like lipids, proteins or DNA. Contrast formation depends on the atomic composition of the particular structure. In the case of DNA, its phosphorous content discriminates it from other biological macromolecules. In our studies, sections of E. coli, the dinoflagellate Amphidinium carterae and Euglena spec. cells were used which were obtained by cryofixation followed by freeze-substitution into acetone with 3% glutaraldehyde. The samples were then embedded either in Lowicryl HM20 at low temperature or in Epon at high temperature. Sections were coated on both sides with 30Å carbon.The DF- and the inelastic image have been recorded simultaneously with a Cryo-STEM. This Cryo-STEM is equipped with a highly dispersive Electron Energy Loss Spectrometer. With this instrument pure Z-contrast can be achieved either with a Filtered DF-image divided by the inelastic image or, as is used in this paper, by dividing the conventional DF-image by an inelastic image which has been recorded with an inelastic detector whose response is dependent on the total energy loss of the inelastically scattered electrons.
Monte Carlo electron trajectory simulation of x-ray emission from films supported on substrates
Authors: Newbury Dale E. , Myklebust Robert L. 
Published: June 2020

Monte Carlo electron trajectory simulation provides a powerful tool for theoretical studies of electron/x-ray interactions in solid targets. The great power of a Monte Carlo technique arises from the stepwise treatment of the electron trajectory in the target, which provides the capability of dealing with unusual geometric boundary conditions which differ from the ideal of a flat, polished, semiinfinite slab. Special targets, such as randomly tilted surfaces, particles, thin foils, and films supported on substrates, can be simulated by a Monte Carlo procedure.It is proper to speak of “a” rather than “the” Monte Carlo procedure because there is no single formulation of the simulation in universal use. A variety of choices exists for the treatment of the scattering and energy loss processes. In particular, the approach to simulating inelastic scattering varies widely. While most calculations consider inelastic scattering by means of a continuous energy loss approximation rather than by modeling the discrete inelastic processes, there are now several different choices proposed for the treatment of energy loss in the low energy range (<3 keV) where the Bethe model proves inadequate.
Experimental determination of the total enhancement factor in x-ray microanalysis of thin overlayers
Authors: Nassiopoulos A. G. , Valamontes E. , Travlos T. , Tsamis C. 
Published: June 2020

The total enhancement factor in X-ray Microanalysis of thin overlayers has been measured at different primary beam energies by comparing the signal from a thin film deposited on a bulk material to that from a thin unsupported film of the same composition. This enhancement factor contains the contribution of both backscattered electrons and characteristic and bremsstrahlung X-rays created in the bulk by the primary beam , which ionize the film in their way out of the sample.The experimental results from a Cu film on different substrates ( Si, Ni and Au ) are compared to Monte-Carlo calculations, performed by the authors. In these calculations [1,2] all three correction factors cited above (backscattering, characteristic and continuous X-rays from the bulk) are taken into account. It is thus demonstated that the contribution of continuous X-rays from the bulk take important values (as high as 12-14%) in cases where the substrate is of a high Z material at high primary beam energies (40 keV).
Quantitative electron probe microanalysis of Be in Nb-Be alloys using an a-factor correction technique
Authors: Burilla Chuck T. 
Published: June 2020

With the advent of Multilayered Dispersion Elements (MLDE) it is now possible to routinely analyze beryllium in the electron microprobe. In NbBe binary alloys the Be x-ray yield is high enough to allow accurate quantitative analysis of this ultralight element. An empirical correction technique, in conjunction with NbBe standards, enables Be intensities to be converted into concentrations. The minimum detection level of Be in Nb is estimated to be less than 0.05 weight percent.series of NbBe binary alloys and Be metal were examined with an electron microprobe. Very favorable Be Ka peak intensities and P/B ratios were obtained with a Boron Carbide/Molybdenum MLDE (2d= 203.6 A ). These values are reported in Table 1. Because of many factors, including the probable high absorption of the ultra-soft Be x rays in the matrix and the huge overvoltages affronted, traditional correction procedures such as ZAF can be expected to fail.
An Empirical Test Of A Thin-Film Analysis Routine On Bisrcacu Oxide Superconductor Precursors
Authors: Ross D.K. , Heyman R.V. , Elthon D. 
Published: June 2020

Until quite recently, electron microprobe analysis techniques were limited to samples of “infinite” thickness, that is, to samples thick enough such that the entire excitation volume was contained within the material of interest. Thin film analysis was not possible with available matrix correction programs, which were based on the assumption of samples of “infinite” thickness. Now however, algorithms are available that permit analysis of thin samples.We have obtained one of the more versatile and sophisticated of these programs. In order to investigate the accuracy of this routine we have analyzed several BiSrCaCuO thin films at 15 kV and repeated the analysis at 30 kV. These films were thick enough such that at 15 kV conventional ZAF data reduction yielded acceptable totals (98-101 %) with minimal substrate x rays observed. At 30 kV, however abundant substrate x rays were observed and ZAF yielded very low totals. X-ray intensity ratios from 30 kV runs were used to estimate film thickness and matrix corrections were applied using the Waldo algorithm.
Quantitative Analysis Of X-Ray Images From Geological Materials
Authors: Paque J. M. , Browning R. , King P. L. , Pianetta P. 
Published: June 2020

Geological samples typically contain many minerals (phases) with multiple element compositions. A complete analytical description should give the number of phases present, the volume occupied by each phase in the bulk sample, the average and range of composition of each phase, and the bulk composition of the sample. A practical approach to providing such a complete description is from quantitative analysis of multi-elemental x-ray images.With the advances in recent years in the speed and storage capabilities of laboratory computers, large quantities of data can be efficiently manipulated. Commercial software and hardware presently available allow simultaneous collection of multiple x-ray images from a sample (up to 16 for the Kevex Delta system). Thus, high resolution x-ray images of the majority of the detectable elements in a sample can be collected. The use of statistical techniques, including principal component analysis (PCA), can provide insight into mineral phase composition and the distribution of minerals within a sample.
Composition Particle-Size Relationship In Atmospheric Aerosol Samples
Authors: Tura J.M. , Xaus C. , Traveria A. , Casassas E. , Garcia F. 
Published: June 2020

The aim of this work is the scanning electron microscopy with x-ray analysis (SEM-EDX) morphological and microanalytical characterization of atmospheric aerosols in a heavy-traffic suburban area. Aerosols are sampled in a cascade impactor, during a full week. For each size-fraction a semiquantitative analysis of the more characteristic elements is perfomed. A synthetic atmospheric aerosol is used as reference material.The collection point was placed in the Montcada relay area by the Barcelona-France motorway. Sampling was perfomed during a week, with daily periodicity. A Sierra-Misco high-volume sampler with a five-stage cascade impactor was used. The aerosol samples were collected in fractions according the particle size on the different stages of the impactor and on a backup cellulose-ester absolute filter. At the flow rate used the cut-off values for the particle size collected in each stage was: 6.4, 3.1, 1.7, 0.8 and 0.39 μm. Sampling time was 24 h and the daily air volume aspired was 2.000 m3 aproximately.
Application Of Electron Microscopy To Automotive Finish Defect Analysis
Authors: Mahon Martin J. , Keating Patrick W. , McLaughlin John T. 
Published: June 2020

Coatings are applied to appliances, instruments and automobiles for a variety of reasons including corrosion protection and enhancement of market value. Automobile finishes are a highly complex blend of polymeric materials which have a definite impact on the eventual ability of a car to sell. Consumers report that the gloss of the finish is one of the major items they look for in an automobile.With the finish being such an important part of the automobile, there is a zero tolerance for paint defects by auto assembly plant management. Owing to the increased complexity of the paint matrix and its inability to be “forgiving” when foreign materials are introduced into a newly applied finish, the analysis of paint defects has taken on unparalleled importance. Scanning electron microscopy with its attendant x-ray analysis capability is the premier method of examining defects and attempting to identify their root cause.Defects are normally examined by cutting out a coupon sized portion of the autobody and viewing in an SEM at various angles.
Raman And Fluorescence Spectra Observed in Laser Microprobe Measurements of Several Compositions in the Ln-Ba-Cu-O System
Authors: Etz Edgar S. , Schroeder Thomas D. , Wong-Ng Winnie 
Published: June 2020

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.
Secondary Ion Mass Spectrometry Studies of Polycrystalline Thin-Film Cdte/Cds Solar Cells
Authors: Asher S.E. 
Published: June 2020

Polycrystalline thin films of CdTe deposited on CdS are one of the most promising materials systems currently being investigated for the fabrication of low cost, large area, high efficiency photovoltaic devices. However, many of the deposition processes being used to fabricate these thin film materials have not yet been well characterized. It has been found that a post-fabrication heat-treatment is necessary to improve the quantum efficiency of these devices. Secondary ion mass spectrometry (SIMS) was used to study the interdiffusion of S and Te in CdTe/CdS structures grown by two different methods. The depth profiles revealed significant differences in the sputtering behavior depending on the film morphology.Two sets of CdTe/CdS samples were studied. The first set of films was deposited at high temperature using a spray pyrolysis technique with no post deposition anneal. The second set of films was electroplated, followed by treatment with CdCl2 and a high temperature anneal.
Cryofixation of Biological Objects
Authors: Müller Martin 
Published: June 2020

The immobilisation of biological material kept under optimally controlled physiological conditions is the first and most critical step when attempting to preserve the complex interactions of organelles, macromolecules, ions and water in close relationship to the living state. Immobilization must be sufficiently rapid, trapping dynamic events at membranes, (e.g. membrane fusion and exocytosis which occur on a milisecond time scale) and preventing the lateral displacement of lipids and proteins within the membranes. Techniques based on chemical immobilisation (aldehyde fixation) seem to approach their limits in this respect, although their use will remain indispensible in solving many relevant biological problems. Chemical fixatives react relatively slowly and cannot preserve all cellular components.Cryoimmobilization represents a farther reaching alternative. Very high cooling rates (10−4 Ksec−1 to 10−6 Ksec−1) are required to prevent the formation and growth of ice crystals by which the structural integrity would be affected. The high cooling rates at the same time bring along a rapid arrest of the physiological events, i.e. a very high time resolution for dynamic processes in the cell and consequently structural immobilisation closely related to the living state.
Specimen Preparation for Clinical Applications of X-Ray Microanalysis
Authors: Shelburne J.D. , Roomans G.M. 
Published: June 2020

Proper preparative procedures are a prerequisite for the validity of the results of x-ray microanalysis of biological tissue. Clinical applications of x-ray microanalysis are often concerned with diagnostic problems and the results may have profound practical significance for the patient. From this point of view it is especially important that specimen preparation for clinical applications is carried out correctly.Some clinical problems require very little tissue preparation. Hair, nails, and kidney and gallbladder stones may be examined and analyzed after carbon coating. High levels of zinc or copper in hair may be indicative of dermatological or systemic diseases. Nail clippings may be analyzed (as an alternative to the more conventional sweat test) to confirm a diagnosis of cystic fibrosis. X-ray microanalysis in combination with scanning electron microscopy has been shown to be the most reliable method for the identification of the components of kidney or gallbladder stones.A quantitatively very important clinical application of x-ray microanalysis is the identification and quantification of asbestos and other exogenous particles in lung.
The Diamond Knife: A Necessary Tool in Light and Electron Microscopy
Authors: Gnaegi Helmut 
Published: June 2020

Since the introduction by H. Fernández-Morán in 1953 [1], the diamond knife has found wide acceptance by the majority of electron microscopists for the preparation of ultrathin sections of biological samples.Through the years the basic architecture of the knife itself remained unchanged: The cutting edge was formed by the intersection of two planes making an angle of approximately 45°. It is assumed that this angle was taken from the nominal 45° angle of the glass knives.Reasons for keeping such values were: By in large, 45° angle diamond knives gave satisfactory results for morphological studies. Factors, other than the sectioning artifacts, seemed to be more important for limiting image quality. In recent years electron microscopes have been developed to an extremely high performance, the resolution reaching atomic level. Due to all of these developments, ultramicrotomy became a needed tool not only for plastic embedded and frozen biological samples, but also in materials research for virtually all types of materials.
Cross-Sectional Imaging of Coated Drug Granules
Authors: Mawn M.P. , Linton R.W. 
Published: June 2020

Coatings on pharmaceutical products serve many purposes such as hiding an unpalatable drug taste, giving increased stability, and providing controlled-release dosage. The analysis of coatings on drug granules has been performed through “bulk” studies, such as dissolution tests, stability tests, and sieve analysis, which provide little direct structural information about the coating. Microstructural information such as coating thickness, uniformity, and porosity is necessary to help optimize processing conditions as well as to predict dissolution behavior and resultant biological activity. A sample preparation method is described which permits successful imaging of granule drug coatings without sampling bias. Information about the coating structure is obtained through morphometric analysis of cross sectioned embedded granules.The granules studied were prepared through a wet granulation process and contain approximately 13% (by weight) drug, 4% corn starch, and 83% sucrose. This inner granule (200-250 μm) was coated (10 μm) with an hydrogenated cotton seed oil in a spray congealing microencapsulating process.