bluuebunny/crossref_metadata_2025_split huggingface dataset:
Apfim Investigation of Segregation in a Nickel Base Alloy
Authors: Thuvander M , Stiller K 
Published: July 2020

Abstract
Segregation of boron, carbon and nitrogen to grain boundaries in a nickel based model alloy has been investigated using atom probe field ion microscopy (APFIM). The material corresponds to a commercial alloy (Inconel 600), but contains lower levels of alloy additives and impurities. The major composition was Ni-16Cr-10Fe (wt.%). The alloy was solution annealed at 950°C for 10 min, which resulted in a grain size of 20 μ. Subsequently heat treatments for 1 h at temperatures of 550°C, 600°C and 700°C were applied. TEM investigation showed that the heat treatment at 700°C resulted in precipitation of intergranular chromium-rich carbides. The other temperatures were obviously too low and the aging times too short to cause precipitation, since carbides were not observed in the materials heat treated at 550°C and 600°C.
As the grain size was about 100 times larger than the accessible depth of APFIM analysis (≃200 nm), much care had to be taken in preparing samples containing a grain boundary close to the tip apex.
Interdisciplinary Development of Eels Compositional Mapping
Authors: Leapman RD 
Published: July 2020

Abstract
Historically, electron energy-loss spectroscopy (EELS) in the electron microscope has evolved from work performed in biological as well as materials science and physics laboratories. The task of developing EELS compositional imaging for biological applications has been particularly challenging for two reasons. First, biological structures are radiation-sensitive and second, elements and compounds of interest are distributed sparsely in a multi-component matrix. For example, the physiologically important element, calcium, is typically present in cells at only 10-100 atomic parts per million.3,5 Even, when individual molecular components of a cell are isolated, elemental concentrations can still be low. Thus, double-stranded DNA contains only six phosphorus atoms per nanometer of its length; and protein molecules typically contain less than 0.5 per cent sulfur. This demand for high sensitivity in biological applications has provided an impetus to improve electron optics, to develop flexible image acquisition methods and to optimize spectral processing.
Multispectral Imaging in Light Microscopy
Authors: Spring K R 
Published: July 2020

Abstract
Many recent applications in light microscopy involve the use of multiple fluorophores or the delineation of signals arising from spectrally distinct sources. In microspectroscopy, it is always desirable to illuminate fluorescently-labeled microscopic specimens with monochromatic light as the narrowest possible excitation wavelength range usually results in the highest emission signal-to-noise ratio. Generation of polychromatic light from an arc lamp and selection of the excitation wavelength by interference filters or monochrometers are the most common techniques for excitation microspectrofluorometry. Emission spectroscopy is usually done with filter wheels, monochrometers, or interferometers inserted between the microscope detection port and the detector. This presentation will be directed toward other, less frequently-used, approaches for spectral scanning of the specimen in the light microscope. Three topics will be considered: 1) the use of acousto-optical tunable filters and lasers for rapid, narrow-band, excitation wavelength selection; 2) the use of holographic notch filters for rejection of unwanted excitation laser light; 3) using liquid-crystal tunable filters for emission scanning.
Quantitative Energy-Filtering Transmission Electron Microscopy (EFTEM) In Materials Science
Authors: Hofer F , Grogger W , Warbichler P 
Published: July 2020

Abstract
Equipping a transmission electron microscope with an energy-filter offers extraordinary advantages for the characterization of both materials science and biological samples. Besides improvements for TEM imaging and electron diffraction like better contrast and resolution, elemental mapping using inner-shell ionizations has become the main application of EFTEM. Elemental maps with resolution down to 1 nm and elemental sensitivities down to a single monolayer have been reported. Using a Philips CM20 equipped with a Gatan Imaging Filter (GIF) for our experimental work, we acquired elemental maps with the three window method (A.E-1r background extrapolation from two pre-edge windows) and jump ratio images (division of post-edge image by a pre-edge image). One important application of EFTEM is the detection of secondary phases in materials e.g. precipitates and grain boundary phases. For example, fig.la shows the TEM-image of a 10%Cr steel with the secondary phases mostly invisible.
Transmission Electron Holography of a GaN/AlxGal-xN Heterostructure
Authors: Wang YC , Kisielowski C , Nelson E C , O’Keefe MA 
Published: July 2020

Abstract
GaN and the related AlN semiconducting materials have recently attracted considerable attention because of their versatile applications for optoelectronics. Large stresses are present in the GaN/AlN thin-film heterostructure and can exceed GPa's. They originate from a large lattice mismatch between the substrate(sapphire)/GaN (14%) and the AlN/GaN interface (-2.7%) in quantum well structures. The strain is expected to induce local piezoelectric fields in these polar materials. It is essential for a further development of GaN based thin films to fully understand the formation and the local strength of these fields. Previous studies show that there are unusual large fluctuations of the patterns in lattice images present across GaN/AlxGa1-xN and GaN/InyGa1-yN quantum wells. They are attributed to compositional fluctuations and have been studied by quantitative high resolution electron microscopy. Differences between the strain profiles and the electrostatic (scattering) potential profiles were observed.
Compositional Characterization of an O-N-O Layer in a Dram Using FE-(S)TEM And EELS
Authors: Kawasaki M , Oikawa T , Ibe K , Park K H , Shiojiri M , Kersker M 
Published: July 2020

Abstract
An O-N-O layer within a DRAM is designed to be an insulator between a single-crystal silicon substrate and a poly-crystalline silicon gate. The nominal structure of the layer is SiO2-Si3N4-SiO2. It has been reported that oxygen and nitrogen diffuse into each other layer while preserving the three layered structure. In order to measure the elemental distribution quantitatively, EELS was used for Si and light elements O and N in this study.
The specimen was cut from a 16M-DRAM device and prepared for TEM observation by the crosssection ion milling method. The O-N-O layer was analyzed using a JEM-201 OF FE-(S)TEM equipped with a scanning imaging device including a High-Angle Annular Dark Field(HAADF) detector which is capable of collecting electrons scattered 50 to 110 mrad, and also a PEELS(GATAN model 676). Fig. 1 shows a HAADF image of the O-N-O layer.
EFTEM and STEM EELS Spectrum Imaging
Authors: Hunt J A , Harmon R H 
Published: July 2020

Abstract
Electron energy-loss spectroscopy (EELS) in the transmission electron microscope (TEM) is a powerful technique that analyzes the inelastic scattering distribution of the fast TEM electrons after they have lost energy within the sample. The resultant energy-losses are characteristic of elemental, chemical, and dielectric properties and are typically measured in one of two ways. Parallel-detection EELS spectrometers (PEELS) acquire spectral data over a large range of energy-loss simultaneously for rapid acquisition of spectral data at a single point. In contrast, the energy filtering TEM (EFTEM) acquires only a single energy band at once, but does so for thousands or even millions of image pixels simultaneously.
Spectrum-imaging concerns the acquisition of spectroscopic data of sufficient detail for rigorous analysis at each pixel in a digital image. (Fig. 1) A STEM EELS spectrum image “data cube” can be acquired by stepping a focused electron probe to each pixel and filling the spectrum image one spectrum at a time.
History and Cross-Disciplinary Perspective of Compositional Imaging and Mapping With Nexafs Microscopy
Authors: Ade H 
Published: July 2020

Abstract
In Near Edge X-ray Absorption Fine Structure (NEXAFS) microscopy, excitations of core electrons into unoccupied molecular orbitals or electronic states provide sensitivity to a wide variety of chemical functionalities in molecules and solids. This sensitivity complements infrared (IR) spectroscopy, although the NEXAFS spectra are not quite as specific and “rich” as IR spectra. The sensitivity of NEXAFS to distinguish chemical bonds and electronic structures covers a wide variety of samples: from metals to inorganics and organics. (There is a tendency in the community to use the term NEXAFS for soft x-ray spectroscopy of organic materials, while for inorganic materials or at higher energies X-ray Absorption Near Edge Spectroscopy (XANES) is utilized, even though the fundamental physics is the same.) The sensitivity of NEXAFS is particularly high to distinguish saturated from unsaturated bonds. NEXAFS can also detect conjugation in a molecule, as well as chemical shifts due to heteroatoms.
Interfacial Segregation and Concentration Profiles by Energy-Filtered Transmission Electron Microscopy: Issues and Guidelines
Authors: Bentley J 
Published: July 2020

Abstract
Over the several years that imaging energy filters have been available commercially, numerous and wide-ranging applications have demonstrated elemental mapping at resolutions approaching 1 nm. From reviewing applications of energy-filtered transmission electron microscopy (EFTEM) to interfacial segregation and concentration profiles in metals and ceramics, some guidelines and issues may be identified. The work has been performed with a Gatan imaging filter (GIF) interfaced to a Philips CM30 operated at 300 kV with a LaB6 cathode.
For quantitative elemental mapping by EFTEM a number of interrelated parameters [field of view, resolution, collection angle (β), slit width (Δ), incident beam divergence (α), illumination uniformity, probe current (i), drift rate, exposure time (T), and local specimen thickness (t)] have always to be properly selected and controlled. For example, the collection angle should be large enough for a strong signal, but not so large that the signal/background (S/B) and chromatic-aberration-limited spatial resolution (δ) are both degraded.
Going Nondispersive
Authors: Heinrich Kurt F J 
Published: July 2020

Abstract
In February 1968 Ray Fitzgerald, Klaus Keil and myself published in Science a communication titled “Solid-State Energy-Dispersion Spectrometer for Electron Microprobe X-ray Analysis”. The authors describe the use of a lithium-drifted silicon detector for the direct identification of x-rays, without a diffracting crystal, in an electron probe. The subject of this paper was to modify profoundly the development of x-ray microanalysis in the years to follow.
Pulse-height analysis of gamma rays detected in scintillation counters was widely used at the time. For radiation of energies below 30 keV, gas proportional counters were also employed. In elementary analysis by x-rays the poor energy resolution of these detectors limited the application of such a procedure, although single-channel pulse height analysis was employed as an adjunct to crystal spectrometers.
In 1951, Raymond Castaing in his thesis described his invention of the electron probe microanalyzer, created by adding to a transmission electron microscope a curved-crystal spectrometer which focused the x-rays emitted by the specimen into a Geiger-Muller counter.
Low Voltage X-Ray Microanalysis of Bulk Bio-Organic Samples
Authors: Echlin Patrick 
Published: July 2020

Abstract
Although high resolution (2nm), low voltage (lkV), SEM of bio-organic materials can now be performed more or less routinely using instruments fitted with a field emission source, virtually no low voltage x-ray microanalysis has been carried out on this type of specimen. Boyes and Nockolds showed that quantitative microanalytical information could be obtained from polished inorganic samples at a spatial resolution of l00nm at 5kV and Johnson et al obtained similar type of data at a spatial resolution of 150nm at 3kV. High spatial resolution (l0nm) microanalysis can be achieved in frozen dried or chemically compromised sections of biological material examined at high voltage in the TEM but frozen hydrated chemically unfixed sections are damaged. The other approach is to use the SEM with frozen hydrated, chemically uncompromised samples, usually at about 10-15kV, in order to obtain sufficient signal from the elements of interest which typically lie in the range Na (Z=l 1) to Ca (Z=20).
EDS of thin Biological Specimen in the Study of Time-Dependent Physiological Processes
Authors: Wendt-Gallitelli MF , Voigt Tilman , Schultz Michael , Rudolf Frank , Isenberg Gerrit 
Published: July 2020

Abstract
The contraction of muscle depends on the ability of intracellular organelles to rapidly release and take up large amounts of activator calcium. In cardiac muscle the intracellular sodium concentration is known to also modulate this Ca2+ release: Na+-Ca2+ exchange creates narrow cytosolic microdomains just internal to the sarcolemma (approximately 20 nm wide) with locally elevated concentrations of Ca2+ and Na+. The existence of such “functional” compartments with transient high ionic concentrations has been postulated for explaining the nigh efficiency of signal transmission during excitation-contraction coupling. We present results showing that electron probe microanalysis (EPMA) at the high spatial resolution of scanning transmission electron microscopy (STEM) can detect changes in sodium and calcium concentration of membrane-limited organelles and functional microdomains provided the cardiac myocytes are rapidly frozen at defined times during activation of contraction.
“Standardless” Quantitative Analysis by Electron-Excited Energy Dispersive X-Ray Spectrometry: What is its Proper Role?
Authors: Newbury Dale E 
Published: July 2020

Abstract
The development of energy dispersive x-ray spectrometry (EDS) has had a profound impact on the methodology of quantitative x-ray microanalysis of thick specimens (i.e., thickness≫ electron range) as performed in electron beam instruments. By equipping the scanning electron microscope (SEM) with EDS, quantitative x-ray microanalysis has become commonly available to a wide range of users, at least some of whom have only a modest background in analytical science. An important aspect of the development of quantitative analysis by EDS has been the extensive analytical experience gained during the development of the electron probe microanalyzer (EPMA) equipped with wavelength dispersive x-ray spectrometers (WDS). The critical measurement step for quantitative WDS analysis was recognized to be the determination of the “k-value”:
k = Iunk / Istd (1)
where I is the measured characteristic intensity of a specific x-ray peak, corrected for background and peak overlaps, for both the unknown and the standard.
Multivariate Statistical Analysis of Particle X-ray Spectra
Authors: Anderson Ian M , Small John A 
Published: July 2020

Abstract
Multivariate statistical analysis (MSA) is a powerful tool for the analysis of series of spectra. This paper explores an application of MSA to a series of energy dispersive X-ray (EDX) spectra acquired in the scanning electron microscope (SEM) from a series of particles. The raw data were series of spectra previously acquired to test analytical procedures for trace element detection. This paper explores the possibility of performing the trace element detection with MSA components that have been extracted from the raw data without any a priori assumptions about the information content of the particle spectra. Particles were prepared from two analytical glasses, dispersed onto carbon substrates and coated with carbon. The compositions of the two glasses are substantially similar, except that one glass (K-3106) contains 0.7 wt.% Fe, whereas the other glass (K-3069) does not contain Fe at a detectable level.
Extracting Chemical Information From Energy-Dispersive X-Ray Spectra by Multivariate Statistical Analysis (MSA)
Authors: Saunders M , Menon ESK , Chisholm DJ , Fox AG 
Published: July 2020

Abstract
The introduction of Multivariate Statistical Analysis techniques such as Principal Component Analysis (PCA) to the study of EDS and EELS spectra has opened up new possibilities for processing spectral data. In conventional EDS analysis each spectrum provides information about the elemental composition of the sample at a specific probe position. Where the signal arises from a single phase this elemental composition corresponds to the chemical composition of the phase. However, where the probe is incident on a multiphase region of the sample it is impossible to make a direct identification of the different chemical phases contributing to the overall spectrum.
With PCA it is no longer necessary to consider the spectra as isolated pieces of information. It is now possible to analyze a series of spectra as a single entity, looking for correlations between the variations in the elemental signals present in the individual spectra.
Statistical Consideration in EDS Microanalysis
Authors: Lifshin Eric 
Published: July 2020

Abstract
The overall precision of electron microprobe measurements has not been studied extensively. It is often only described in terms of the precision of individual x-ray measurements or worse yet by relying on some rule of thumb based on historical experience. This is unfortunate because the analyst is expected to determine whether his or her measurements can distinguish between two samples or if a particular component can be detected above background or in the presence of other elements. Thus precision is at the heart of establishing composition/structure/property relationships and clearly deserves more attention.
There are many sources of variability encountered in determining composition whether using energy dispersive (EDS) or wavelength dispersive (WDS) spectrometery. These include Instrumental Variables, i.e., beam voltage and current, specimen position and orientation, detector position, and measurement electronics; Specimen Preparation, i.e., how representative the sample is of the problem to be solved, specimen preparation and contamination, and quality of standards; Data Processing, i.e.,
Trace Element Quantitation in Biological X-Ray Microanalysis
Authors: Leapman RD , Swyt-Thomas CR , Agoston D v , Pivovarova N , Andrews SB 
Published: July 2020

Abstract
In high-resolution biological energy-dispersive x-ray (EDX) microanalysis it is often necessary to measure very low elemental concentrations. As an example, calcium, a physiologically important element, typically occurs in subcellular compartments at concentrations of 10-100 atomic parts per million (corresponding to 1-10 millimole/kg dry weight of sample) and it is ultimately desirable to measure the concentration of this element with a standard error of ±1 atomic ppm (or ± 0.1 millimole/kg). Detection of calcium in biological specimens is further complicated by the presence of relatively high levels of potassium (around 0.5 atomic % or 500 millimole/kg), which gives rise to overlap of the K Kβ and Ca Kα peaks in the EDX spectrum. Counting statistics are frequently the limiting factor for detectability, but this is not necessarily the case because in the analytical electron microscope it is possible to collect spectra for long periods using a high probe current.
K-Factor Standards for Low-Z Quantification
Authors: Egerton Ray , Malac Marek 
Published: July 2020

Abstract
Although elements of low atomic number (Z&lt;11) are detectable in TEM specimens using a modem energy-dispersive (EDX) detector, quantification remains a challenge. Problems include the large absorption corrections needed for specimens of typical thickness and the need for calibration specimens which provide k-factors appropriate to a particular detector/window arrangement. We have addressed this second problem by fabricating thin films containing several light elements in combination with silicon, which typically acts as the reference element when specifying k-factors.
Because the EDX peaks of adjacent light elements overlap considerably, it is preferable to have two specimens: one containing C, O and Si, the other B, N, F and Si. We have used both e-beam evaporation and sputtering techniques to deposit thin films on a substrate which can later be removed to leave a freestanding film mounted on a TEM grid.
Critical Role of EMPA in Discovery of a New Lunar Mineral
Authors: Snow M G , Vaniman D T 
Published: July 2020

Abstract
Natural rock-forming minerals and many synthetic materials have traditionally been characterized by electron microprobe analysis (EMPA). However, recent advances in technology have created attractive alternatives to EMPA that focus instead on bulk chemistry and high-resolution surface studies. The purpose of this abstract is to demonstrate the continued usefulness of careful electron microprobe analysis as part of a well-coordinated analytical study. To this end, a brief summary is presented of the role the electron microprobe played in the recent discovery of yoshiokaite, a new Ca, Al-silicate mineral and one of only three new minerals discovered on the Moon.[l]
Regolith breccias returned by several Apollo missions were subjected to extensive bulk chemical studies at the University of California, Los A n geles.[2] These bulk chemical studies focused particularly on key trace elements that might identify exotic regolith breccias.
The Effect of MASS in Electron-Solid Interactions and the Mystery of the “Heinrich Kink”
Authors: Donovan JJ , Pingitore NE 
Published: July 2020

Abstract
Is average atomic mass or average atomic number more appropriate to describe backscattered electron (BSE) effects in electron-solid interactions? In electron microprobe literature, either one or both of the terms A and Z may be found utilized in various theoretical models to describe electron backscattering. Physical theory would seem to favor atomic number averaging, because backscattering ultimately represents an electromagnetic interaction between the electron and the nucleus. At this scale, mass and its associated property of gravity, is 10 times less powerful than the electromagnetic force. Nonetheless, some empirical results show a strong relation between atomic mass and electron scattering, thus endorsing mass averaging.
The periodic table presents an opportunity for distinguishing between these two influences: those pairs of elements for which an increase in Z yields a decrease in average A (e.g., Ar-39.95 and K-39.10; Co-58.93 and Ni-58.71; Te-127.60 and 1-126.90) due to natural isotope abundances.
Refining Equipment for High Resolution in-Lens Cryo-Sem
Authors: Apkarian Robert P , Lee Stephen , Keiper Jason 
Published: July 2020

Abstract
Advanced metal coating methods have greatly improved the localization of secondary electrons (SEI) from biological specimens staged in an in-lens field emission SEM. Using these metal coatings, molecular level structural information from cell membranes and isolated bio-molecules have been more accurately recorded from frozen-hydrated samples due to the presence of bound water rather than from chemically fixed and dried samples. Although in-lens cryo-SEM systems have provided images with equivalent resolution to TEM-replicas, several conditions are encountered which require optimizing techniques and hardware.
A drop of hydrated Bakers yeast on a gold Balzers carrier was plunge-frozen in ethane at its melting point. Thermal properties of ethane, such as the large difference between melting and boiling points, and its low viscosity increase the heat transfer coefficient during plunging thereby leading to faster cooling of the sample than with other cryogens. Carriers were transferred to the cryo-workstation of the Oxford CT 3500 system.