bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-resolution backscattered electron images in the scanning electron microscope
Authors: Wells Oliver C. , Cheng P.C. 
Published: June 2020

In this discussion the words “high resolution imaging” of a solid sample in the scanning electron microscope (SEM) mean that details can be resolved that are considerably smaller than the penetration depth of the incident electron beam (EB) into the specimen. “Atomic resolution” in either the transmission electron microscope (TEM) or scanning transmission electron microscope (STEM) means that columns of atoms are resolved.Image contrasts in the backscattered electron (BSE) image are strongly affected by the specimen tilt and by the position and energy sensitivity of the BSE detector. The expression “BSE image” generally implies that the specimen is normal to the beam and the detector is above it. This shows compositional variations in the specimen with a spatial resolution limited by the spreading of the EB during the initial stages of penetration. This is similar in basic principle to the Z-Contrast method in the STEM that shows atomic resolution from a thinned single crystal mounted in the magnetic field of the focusing lens.
The use of L x-ray spectra of the first-series transition elements for quantitative analysis with the electron microprobe
Authors: Rémond G. , Fialin M. , Gilles C. 
Published: June 2020

For the first transition-series metals with filled or partly filled 3d shells, the final states of the soft L x-ray emission bands are valence hole states ant their L emission spectra have been intensively used to investigate the valence electronic structure. The possible use of the Lα lines of these elements for quantitative analysis by x-ray spectrometry with the Electron Probe Micro-Analyzer is discussed and illustrated for the case of the Zn Lα emission band analyzed with a TAP monochromator.As shown in Figure 1 the Zn Lα emission band of pure metallic zinc exhibits an asymmetrical shape resulting from a broad tail occurring on the short wavelength side (high energy side) of the peak. This tail is the envelope of many unresolved closely spaced satellite features which arise from the deexcitation of the L3 vacancy in the presence of multiple outer vacancies. The digitally recorded Zn Lα emission band was processed by adding Gaussian offsets to the pseudo-Voigt profile of the Zn Lα diagram line used as a fitting function.
Layered and ion implantation specimens as possible reference materials for the electron-probe microanalysis
Authors: Remond G. , Packwood R.H. , Gilles C. , Chryssoulis S. 
Published: June 2020

Merits and limitations of layered and ion implanted specimens as possible reference materials to calibrate spatially resolved analytical techniques are discussed and illustrated for the case of gold analysis in minerals by means of x-ray spectrometry with the EPMA. To overcome the random heterogeneities of minerals, thin film deposition and ion implantation may offer an original approach to the manufacture of controlled concentration/ distribution reference materials for quantification of trace elements with the same matrix as the unknown.In order to evaluate the accuracy of data obtained by EPMA we have compared measured and calculated x-ray intensities for homogeneous and heterogeneous specimens. Au Lα and Au Mα x-ray intensities were recorded at various electron beam energies, and hence at various sampling depths, for gold coated and gold implanted specimens. X-ray intensity calculations are based on the use of analytical expressions for both the depth ionization Φ (ρz) and the depth concentration C (ρz) distributions respectively.
Evaluation of particle effects in bremsstrahlung and in quantitative energy-dispersive x-ray microanalysis
Authors: Lu Yun , David C. Joy 
Published: June 2020

The magnitude and the spectral form of bremsstrahlung signal contains much information about the target and is significantly influenced by the surface irregularities. By computer modelling, it is possible to extract the information to perform more accurate quantitative x-ray microanalysis for specimens with special geometries. In this research, bremsstrahlung spectra obtained from electron beams striking at selected locations of spherical particles were investigated by Monte Carlo simulations and experimental observations. The effects of surface geometries and the x-ray path lengths in the specimens on the variation of bremsstrahlung spectra and peak-to-background ratios were studied.The Monte Carlo electron trajectory calculations were determined with a screened Rutherford cross-section and a plural scattering model. The continuum x-ray depth profile is computed using Kramer's bremmstrahlung cross-section. The cross-section for inner shell ionization proposed by Green and Cosslett were employed for calculating characteristic x-rays. Bethe stopping power was determined by using the Luo-Joy modification at low energies. The mass absorption coefficient was calculated using Heinrich expression. The detector efficiency was determined experimentally.
Electron Stopping Powers and their Experimental Determination
Authors: Joy David C , Luo Suichu , Zhang Xiao 
Published: June 2020

Electron stopping power is one of the most important fundamental parameters describing the interaction of an electron with a solid. The magnitude of the stopping power and its variation with energy determines the range of the electron, the rate of production of secondary electron, electron-hole pairs, and the exact form of the ϕ(ρz) curve. In its simplest form the stopping power, i.e the energy dE transferred to the sample of density ρ, atomic number Z and atomic weight A, as the electron of energy E travels a distance ds, is:(1)where the mean ionization potential I represents all of the possible inelastic scattering events available to the electron and is, to a zero-order approximation, about 11.6*Z eV. It has been well established that equation (1) is an accurate prediction of the stopping power at energies E of the order of tens of keV, but at the lower energies (i.e <10keV) of most interest for microprobe analysis and scanning microscopy the situation is more complicated.
EELS Study of Phase Separation in Glasses
Authors: Qing Chen Quan , Ming Chu Yi , Feng Duan Xiao 
Published: June 2020

The phase separation in glasses plays a great role in the glass science and technology. By controlling the chemical composition and the degree of phase separation, it is possible to produce various kinds of materials of predicted microstructure. To determine the kinds of separated phases, the chemical composition and the fraction or sizes of each separated phase are the main problem in thermodynamics and kinetics study of phase separation in glasses. The sizes of phase separated particles are usually in the range of several nm to several hundred nm, which can be determined by a rather simple method instead of the small angle x-ray scattering with trivial calibration. It has been showed that electron energy loss spectroscopy (EELS) not only can be used to determined the constituents of at. No. 2-92 but also is more sensitive than EDS.Two phase separated glasses of initial composition 8Na2O27B2O3 65SiO2 and 60ZrF431BaF25LaF34AlF3 were used to prepare specimens by ion bombardment.
An attempt to get an EEL filter image of biological sections using a spectrometer and a scanning device
Authors: Futaesaku Yutaka , Sekiya Kachiko , Ono Michiko , Nakamura Atsushi , Nakamura Yoshiko , Ueno Masaki 
Published: June 2020

An amount of light elements contained in biological specimens is barely a few, so that the detection of them in the ultrathin sections is imposible. An analysis of electron energy loss (EEL) filter image is an ideal to detect such as phosphorus including in the sections. CEM-902 is a commercially available electron microscope to use for a such purpose. The authers attempted to get EEL filter images using the combined system of a conventional scanning transmission electron microscope (STEM) with EELS analyzer.The cultured cells with calcified substances and the liver, kidney, thyroid gland were used for biological specimens. There were fixed with 2.5% glutaraldehyde and with or without 1% osmium tetroxide, and then embedded in epoxy resin. 40 run thick sections were analyzed without any staining and carbon coating using a Carl Zeiss CEM-902 or a JEOL 2000EX with a EELS analyzer and a Tracor-Northern TN-5500, and with a Gatan cryo-transfer holder.
AEM Characterization of Particles in Electrodeposited Chromium Plates
Authors: Chang Li , Tsai Rung-Ywan , Wu Shinn-Tyan 
Published: June 2020

Electrodeposited Cr plating has been used for steel surface hardening since 1930. It is well known that there are particles precipitated during annealing the plate. However, no direct evidence has been shown to identify the species of the particles. Despite several microstructural characterizations having been carried out about thirty years ago it is surprised that no research has been done yet for the past decade to take the advantage of the powerful strength of modern electron microscopy. The present work reports the identification of the particles on the basis of AEM study.Cr plates were deposited on plain carbon steels by conventional method using a standard solution containing CrO3 250 g/l and H2SO4 2.5 g/l at a current density 40 A/dm2 and 45°C. The plates of 0.1mm thickness were then stripped off from steel substrate by dilute HNO3 before annealing was carried out in vacuum at 600,700, and 800°C for 1 to 6 hours.
Defining the Surface-Adsorbed Oxygen Layer with the Channeling Effect in Reflection Electron Energy Loss Spectroscopy
Authors: Wang Z. L. , Bentley J. 
Published: June 2020

Channeling conditions or resonance conditions have to be satisfied in order to enhance image contrast in reflection electron microscopy (REM) and the signal to background ratio in reflection electron energy-loss spectroscopy (REELS). The introduction of the channeling effect can complicate surface microanalysis, but could be used to detect surface adsorbed molecules.An α-A12O3 (01) surface can be terminated with a layer of O−2 or a layer of Al+3. For the surface domain terminated initially with O−2, the oxygen ions will become positively charged after losing three Auger electrons. Then the O+1 ions will be desorbed by the electron beam and the surface 2-D periodic structure becomes disturbed and shows dark rough contrast in the REM image (the dark domain in Fig. 1). Regions of the newly formed surface are terminated with Al+3. For the domain terminated initially with Al+3, the surface is believed to be oxidized quickly in air and is covered by a thin “amorphous” layer, which does not affect the image contrast but protects the surface from being damaged; then the surface shows smooth bright contrast in REM (the bright domain in Fig. 1).
An Aberration-Minimized Imaging Energy Filter of Simple Design
Authors: Krahl Dieter , Pätzold Hans , Swoboda Manfred 
Published: June 2020

The installation of an imaging energy filter extends the imaging and analytical capabilities of a conventional transmission electron microscope considerably (contrast and resolution improvement, filtering of diffraction diagrams, EELS and elemental mapping, recording of angle-resolved energy spectra).Unfortunately, second-order aberrations especially in purely magnetic systems, known up to now, disturb the resolution in off-axis areas of the transferred image. Furthermore, an aperture aberration in the energy-dispersive plane introduces in off-axis areas a shift of the selected energy range. In principle these aberrations can be corrected by inserting sextupole correctors and/or curved edges. But it should be mentioned that the achievable correction of such an improved filter very strongly depends on a proper alignment of the beam.We describe an aberration-minimized purely magnetic energy filter. The imaging properties of the system were calculated taking into account the exact fringing fields of the reflection magnets. The system was tested on a Zeiss microscope.
The Application of Bio-Standards for Electron Energy-Loss Analysis of Biological Materials
Authors: de Bruijn Wim C. , Sorber Lianne W.J. 
Published: June 2020

The application of standards, with a known externally determined element concentration, for the determination of unknown concentrations in cell organelles and tissue is a well known practice in X-ray microanalysis.The conditions to be met for a good standard have been formulated earlier. Pure element standards and standards made from PVP-films have been proposed for Electron Energy loss analysis. In this presentation we investigate the use for EELS-analysis of the ion-exchange bead Chelex100-type of standards, which can be co-embedded with tissue and have been applied successfully for X-ray microanalysis.The ion-exchange characteristics, the methods of loading and the matrix composition have been described before. Such bio-standards, which can be loaded with a variety of cations, are stored as a dry powder and can be co-embedded with the tissue to be analyzed. In that way the standard is present in each ultrathin section, at (an assumed) equal thickness as the cells or tissue, containing the unknown concentration of that element.
Development of a Field Emission TEM and Some Applications in Materials Science
Authors: Hashimoto T. , Isakozawa S. , Ichihashi M. , Kamino T. 
Published: June 2020

We have completed development of a cold field emission TEM , Model HF - 2000 at Hitachi, Ltd. in Japan. The HF - 2000 has the following unique features.1)High sensitivity and precise elemental micro-analysis is possible with a high intensity beam of a cold field emission source.2)Crystal structure analysis by electron diff-raction technique with a fine probe of high coherency (small illumination angle).3)High resolution imaging beyond the conventional limits of thermionic elecron sources will be made possible by a beam of high coherency and small energy spread.Condenser lens system of the HF - 2000 has been designed for ease of operation just as the conventional instruments. The beam current density available on the specimenis about 100 times greater than that available with conventioal instruments.Fig. 1 is a TEM image of Pd/Te particles on carbon with electron diffraction patterns of two partciles A and B. Fig . 2 shows two EDX spectrum of the same two particles.
Spectral Deconvolution of Wavelength Dispersive X-RAY Spectra
Authors: Rémond Guy 
Published: June 2020

X-ray peaks frequently exhibit asymmetrical shape which may result either from the mechanisms of generation of X-ray photons or from instrumental spectral distortions. As a result a non-proportionality may occur between the observed and the true intensities of the analyzed emissions. An analytical description of the shape of an X-ray line must be used in a least-squares fitting procedure in order to derive the relative intensities from experimental spectra. The available models will be discussed taking into account the analyzed energy domain and the energy resolution of the spectrometer respectively.For the case of wavelength dispersive X-ray spectrometry, Remond et al. (1) showed that the shape of an L emission peak P(λ), analyzed by means of a LiF (200) monochromator (≈ 0.1nm < λ < ≈ 0.3nm) was correctly described by the use of equation [1].[1]where P1(λ) and P2(λ) are a Gaussian and a Lorentzian distribution respectively, centered at the same wavelength, with the same amplitude and half-width at half-maximum Γ, (HWHM) and in relative proportion k.
Software Tools for Examination of Microanalytical Images
Authors: Bright David S. 
Published: June 2020

Image processing for enhancement and interpretation is a powerful tool for microscopy and microanalysis. Digital images are arrays of picture elements or pixels each having a coordinate (location) and a value. Two dimensional arrays with single intensity value (monochrome) or triple intensity values (color) pixels are in common use. Software tools and techniques are now available for desk top computers at reasonable cost that allow visualization of higher dimensional arrays and multivalued pixels. The following examples illustrate the application of these tools to microanalysis.Short image sequences (movies) are useful for showing dynamic effects such as the drift of an electron microscope stage with time or the interior of a sample eroded by sputtering on an ion microscope.The values of the pixels of registered images or x-ray maps can be accumulated in a multidimensional histogram (Concentration Histogram Image or CHI). The number of registered maps determines the dimensionality of the histogram.
An SEM Study on Acid Activated Monotmorillonite
Authors: Shu nian Li 
Published: June 2020

Under an action of acid the monotmorillonite is changed in the shape, chemical composition, construction and chemical-physical properties. Such changes ralete with concentration and quatity of the acid. The change law has been studied by SEM, EDAX and X-ray diffraction.All process that the monotmorillonite with shape of cotton and scale is disintegrated gradually is observed by SEM. Begin the monotmorillonite ture into losse and appear holes, increased with concentration of the acid, finally it disntegrate into many of small particles(Figures 1-4).Changes of chemical composition of the monotmorillonite have been determined by EDAX very conveniently and quickly. The results show that content of SiO2 is increase and Al2O3, Fe2O3,MgO, Na2O, K2O, CaO, TiO2 is dectease.The results of X-ray diffraction and differential thermo-analysis show the process that crystal construction of the monotmorillonite is destroyed under acidic action, i. e., increased with concentration of the acid, d001 and d060 peakes disappear gradually.
Microanalytical Identification of a New Zr-Nb-Fe Phase
Authors: Woo O.T. , Carpenter G.J.C. 
Published: June 2020

To study the influence of trace elements on the corrosion and hydrogen ingress in Zr-2.5 Nb pressure tube material, buttons of this alloy containing up to 0.83 at% Fe were made by arc-melting. The buttons were then annealed at 973 K for three days, furnace cooled, followed by ≈80% cold-rolling. The microstructure of cold-worked Zr-2.5 at% Nb-0.83 at% Fe (Fig. 1) contained both β-Zr and intermetallic precipitates in the α-Zr grains. The particles were 0.1 to 0.7 μm in size, with shapes ranging from spherical to ellipsoidal and often contained faults. β-Zr appeared either roughly spherical or as irregular elongated patches, often extending to several micrometres.The composition of the intermetallic particles seen in Fig. 1 was determined using Van Cappellen’s extrapolation technique for energy dispersive X-ray analysis of thin metal foils. The method was employed to avoid corrections for absorption and fluorescence via the Cliff-Lorimer equation: CA/CB = kAB · IA/IB, where CA and CB are the concentrations by weight of the elements A and B, and IA and IB are the X-ray intensities; kAB is a proportionality factor.
Changes in corneocyte element concentrations occur in skin inner stratum corneum
Authors: Warner R. R. 
Published: June 2020

Keratinocytes undergo maturation during their transit through the viable layers of skin, and then abruptly transform into flattened, anuclear corneocytes that constitute the cellular component of the skin barrier, the stratum corneum (SC). The SC is generally considered to be homogeneous in its structure and barrier properties, and is often shown schematically as a featureless brick wall, the “bricks” being the corneocytes, the “mortar” being intercellular lipid. Previously we showed the outer SC was not homogeneous in its composition, but contained steep gradients of the physiological inorganic elements Na, K and Cl, likely originating from sweat salts. Here we show the innermost corneocytes in human skin are also heterogeneous in composition, undergoing systematic changes in intracellular element concentration during transit into the interior of the SC.Human skin biopsies were taken from the lower leg of individuals with both “good” and “dry” skin and plunge-frozen in a stirred, cooled isopentane/propane mixture.
Electron probe analysis of calcium and magnesium movements in photoreceptor endoplasmic reticulum
Authors: Baumann Otto , Walz Bernd , Somlyo Andrew P. 
Published: June 2020

Various physiological stimuli mobilize Calcium from an intracellular store by a reaction cascade comprising a cell-surface receptor, a coupled G-protein, a phospholipase C and inositol 1,4,5-trisphosphate. Although there is strong evidence that the endoplasmic reticulum (ER) is the target of Ins(l,4,5)P3 and regulates cytoplasmic Ca in non-muscle cells some authors still claim that a specialized, independent cell organelle is the Ins(l,4,5)P3-sensitive Ca-store. The purpose of our study was to determine, with electron probe x-ray microanalysis, the elemental composition of the ER in situ, at rest and during cell stimulation.We used honey bee photoreceptors because their large ER-cisternae allow direct sampling of the luminal contents without cytoplasmic contamination (Fig. 1). Retinal slices were incubated in a Ringer solution which contained 400 mM sucrose to increase the osmolarity and to serve as cryoprotectant. The slices were frozen with a LifeCell CF 100 slam-freezer either while dark-adapted or after a 3 sec light stimulus.
Is there a “universal” MAC equation?
Authors: Ogilvie Robert E. 
Published: June 2020

The search for an empirical absorption equation begins with the work of Siegbahn (1) in 1914. At that time Siegbahn showed that the value of (μ/ρ) for a given element could be expressed as a function of the wavelength (λ) of the x-ray photon by the following equationwhere C is a constant for a given material, which will have sudden jumps in value at critial absorption limits. Siegbahn found that n varied from 2.66 to 2.71 for various solids, and from 2.66 to 2.94 for various gases.Bragg and Pierce (2) , at this same time period, showed that their results on materials ranging from Al(13) to Au(79) could be represented by the followingwhere μa is the atomic absorption coefficient, Z the atomic number. Today equation (2) is known as the “Bragg-Pierce” Law. The exponent of 5/2(n) was questioned by many investigators, and that n should be closer to 3. The work of Wingardh (3) showed that the exponent of Z should be much lower, p = 2.95, however, this is much lower than that found by most investigators.
Eds Of Radioactive Particles By Self-Induced Fluorescence
Authors: Finch Gregory L. , Cuddihy Richard G. 
Published: June 2020

The elemental composition of individual particles is commonly measured by using energydispersive spectroscopic microanalysis (EDS) of samples excited with electron beam irradiation. Similarly, several investigators have characterized particles by using external monochromatic X-irradiation rather than electrons. However, there is little available information describing measurements of particulate characteristic X rays produced not from external sources of radiation, but rather from internal radiation contained within the particle itself. Here, we describe the low-energy (< 20 KeV) characteristic X-ray spectra produced by internal radiation self-excitation of two general types of particulate samples; individual radioactive particles produced during the Chernobyl nuclear reactor accident and radioactive fused aluminosilicate particles (FAP). In addition, we compare these spectra with those generated by conventional EDS.Approximately thirty radioactive particle samples from the Chernobyl accident were on a sample of wood that was near the reactor when the accident occurred. Individual particles still on the wood were microdissected from the bulk matrix after bulk autoradiography.