bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparison of the Elemental Concentrations Obtained using X-ray Microanalysis of Bulk Cryofractured and Ultrathin Cryosectioned Mucus Layer of the Airway Surface Liquid in Mouse Trachea
Authors: Ackerley CA , Kent G , Heng YM , Tilups A , Becker LE
Published: July 2020

The airways are lined with a thin film consisting of two layers. A watery layer, the airway surface liquid (ASL) surrounds the cilia and its major function is to serve as a medium for ciliary boating of mucus out of the respiratory system. The other layer is a viscous mucus layer consisting mainly of airway cellular secretions and cellular debris.

The composition and effects of altered concentrations of the constitutive elements in the ASL and mucus layer remain a mystery. in human patients, attempts have been made to determine the composition of these layers by sampling with a filter paper by touching it to the mucosa and wetting it by capillary action. This material was then removed from the filter paper and quantitative analyses using energy dispersive x-ray spectrometry (EDS) and a Hall’s thin film correction routine performed on the residue. Although differences were detected between normal and pathological material, these results did not reflect the composition of the individual layers but an average of both.

Attempts have been made to determine the elemental composition of these layers in intact and in cultured rabbit trachea, bovine trachea and hamster trachea.
Defining the Tools: an Analysis of Laser Scanning Confocal and Wide-Field/Restoration Fluorescence Microscope Imaging
Authors: Swedlow Jason R , Andrews Paul D , Hu Ke , RoosT David S , Murray John M
Published: July 2020

Digital fluorescence microscopy is now a standard tool for determining the localization of cellular components in fixed and living cells. Two fundamentally different imaging technologies are available for imaging fluorescently labelled cells and tissues, in either the fixed or living state. The laser scanning microscope uses a diffraction-limited focused beam to scan the sample and develop an image point by point. in addition, a pinhole placed in a plane confocal to the specimen prevents emitted out-of focus fluorescence from reaching the photomultiplier tube (PMT) detector. By combining spot illumination and selection of infocus fluorescence signal, the laser scanning confocal microscope (LSCM) creates an image of the specimen largely free of out-of-focus blur. By contrast, a wide-field microscope (WFM) illuminates the whole specimen simultaneously and detects the signal with a spatial array of point detectors, usually a charge-coupled device camera (CCD). This approach collects an image of all points of the specimen simultaneously and includes all the out-of-focus blurred light. Subsequent restoration by iterative deconvolution generates an estimate of the specimen, largely free of out-of-focus blur. While many other fluorescence imaging modalities exist, these two methods represent the majority of the fluorescence imaging systems currently in use in biomedical research.
Live Confocal Analysis of Fertilization and Early Development
Authors: Tram Uyen , Sullivan William
Published: July 2020

Embryonic development is a dynamic event and is best studied in live animals in real time. Much of our knowledge of the early events of embryogenesis, however, comes from immunofluourescent analysis of fixed embryos. While these studies provide an enormous amount of information about the organization of different structures during development, they can give only a static glimpse of a very dynamic event. More recently real-time fluorescent studies of living embryos have become much more routine and have given new insights to how different structures and organelles (chromosomes, centrosomes, cytoskeleton, etc.) are coordinately regulated. This is in large part due to the development of commercially available fluorescent probes, GFP technology, and newly developed sensitive fluorescent microscopes. For example, live confocal fluorescent analysis proved essential in determining the primary defect in mutations that disrupt early nuclear divisions in Drosophila melanogaster. For organisms in which GPF transgenics is not available, fluorescent probes that label DNA, microtubules, and actin are available for microinjection.
Artifacts in Biological Confocal and Non-linear Microscopy
Authors: Cheng Ping-chin , Cheng Wayne Y
Published: July 2020

Conventional histological sectioning and staining techniques produce tissue sections, by large, independent from each other (e.g. the staining intensity depends on the total stainable substance within the section, but not influence by the section above or below it). Although the hardness of the structure in a given section may influence the quality of the following sections, never the less, each physical section can be generally regarded as an independent sampling event. However, the image intensity and relative contrast in an optical section obtained from confocal or non-linear optical microscopy varies depending on the position of the section where it was obtained. Therefore, in sampling terms, optical sections are dependent sampling events. Artifacts caused by the geometry and optical properties (e.g. absorption, scattering, refractive index) of objects within a specimen can interfere the interpretation of the result and hinder the usefulness of three-dimension reconstruction. Figure 1 demonstrates intensity variation in confocal and multi-photon micrographs due to the geometry of the specimen. Depends on the absorption coefficient and path length of the illumination and the fluorescecent light, a solid spherical object produced a 3D data set, when reconstructed, resemble an inverted Chinese rice bowl. Figure 2 shows a 3D reconstruction of an Arabidopsis thaliana mesophyll protoplast; note only half of the spherical cell facing the illumination is imaged as shown in the cut-off view in FIG 3.
Multicolor Labeling for Multidimensional Microscopy: Labels to Dye for
Authors: Rosa-Molinar Eduardo , Quiron Mitch , Smith Jeffery
Published: July 2020

We previously described two techniques to selectively label and/or stain myelinated and unmyelinated nerve fibers and simultaneously stain bone and cartilage. We used antiacetylated α-tubulin immunohistochemistry and anterograde and retrograde transport of selectively applied 3000 molecular weight (MW) biotin dextran amines (Molecular Probes, Inc. Eugene OR) to follow the course, peripheral branching, and origin of the ventral spinal nerve innervating the axial musculature. Those procedures were combined with an enzyme clearing and staining procedure for the simultaneous visualization of bone (alizarin red S) and cartilage (alcian blue) in whole-mount preparations. Use of the techniques enabled us to describe spatial and temporal changes of nerve fibers and the corresponding changes of the osseous elements during the transposition of the anal fin appendicular support of the Western Mosquitofish, Gambusia affinis affinis.

We have extended these techniques by selective multicolor anterograde and retrograde labeling of spinal motor neuron cell bodies, their dendritic arbors, and their ventral motor nerves. We used low (3000) molecular weight (MW) fluorescent lysine-fixable dextrans (Texas Red® and fluorescein) and biotinylated lysine-fixable dextrans (biotin and fluorescein conjugated to biotin), Nissl stains, and fluorescent conjugates of cholera toxin subunit B (Molecular Probes, Inc, Eugene OR).
DNA Nanowires
Authors: Hainfeld JF , Furuya FR , Powell RD , Liu W
Published: July 2020

Current computer chip technology is based on lithographic methods that limit components to ∼0.3 microns in size, due to the wavelength of light, and the photoresist/coating/etching processes. The size directly determines computer speed, complexity and cost, and advances in computers over the years have mostly been due to reduction in component size. It is here proposed to construct nanowires that are approximately 2 nm in diameter, or 150 times smaller than currently available. For 2 dimensions, this translates into a 1502 = 22,500-fold computational advantage. Additionally, 3 dimensional construction is proposed, bringing the potential improvement factor to 3,375,000. While it is probably unrealistic that this factor of packing density can be fully achieved, even several orders of magnitude improvement over current technology would be significant.

A wire width 2 nm may be achieved by placing gold quantum dots along a DNA template. Ends of the DNA-nanowire may be designed with sequences to attach by hybridization to complementary sequences on target connection pads, so that the two ends will seek and automatically wire correctly in solution. This strategy is easily adaptable to 3-dimensional wiring. Conduction between gold quantum dots may be studied as a function of spacing, size and coatings.
Development of New Marker Compounds for the Detection of Chemical Element Labels by Electron Spectroscopic Imaging (ESI)
Authors: Raddatz S , Mark E P , Haking A , Probst W , Wiessler M , Trendelenburg M F , Troester H
Published: July 2020

A promising aspect of ESI is its application in the detection of elemental labels introduced into biomolecules for cell and molecular biological techniques. Even though colloidal gold labeling for electron microscopy (EM) is highly developed, availability of alternative labels, especially for double or triple labeling applications would be helpful because of difficulties with gold concerning i) detection (gold diameters ≤1nm), ii) discrimination due to gold particle size variations in one size class, and iii) different labeling efficiencies depending on gold granule size. An alternative labeling molecule should contain a high concentration of a specific chemical element which is not or in minor concentrations present in the system under surveillance, and has to have the potential to be discriminated from “biological” elements by ESI.

With respect to ESI, one candidate for elemental labeling is boron. It meets the criteria described above and substantial experience in the synthesis of labeling compounds exists. From the chemical point of view, the preferred labeling structure is a so called dendrimer, a highly branched regular three-dimensional monodisperse macromolecule. Dendritic structures offer a large variety of functionalities to incorporate an element detectable by energy filtering transmission electron microscopy (EFTEM).
The Complex Oxidation Behavior of Pd Combustion Catalysts
Authors: Lester K , Datye AK
Published: July 2020

Combustion of natural gas for power generation leads to NOx formation due to the high temperatures encountered. Catalytic combustion allows the entire combustion process to be completed at temperatures where NOx formation can be avoided. The catalyst of choice is supported PdO. As temperature is increased, PdO decomposes to Pd metal with profound effects on catalyst reactivity. Persistent hysteresis in reaction rates have been related to the decomposition of PdO into Pd and its reformation.

Understanding and controlling the phase transformations, and the resulting activity variations, is of enormous importance for high temperature combustion catalysts where predictable catalyst activity is necessary for stable operation. Farrauto et al. studied the phase transformations of PdO to Pd using thermogravimetric analysis (TGA). They concluded that while PdO decomposes to Pd at high temperatures during the heating cycle, upon cooling the Pd does not transform to PdO till the temperature drops by several hundred degrees.
Quantitative Electron Diffraction from Small Volumes
Authors: Twesten RD , Zuo JM
Published: July 2020

Heterogeneous catalysts are extremely important to the chemical industry. The goal of much current research is to develop predictive models for real world catalysts in order to optimize and exploit new processes. The first step in any predictive modeling is to understand the systems that are currently in use. A key question regarding these materials is the distribution of atoms within the catalyst particle, i.e., are the materials equally distributed within the particle or is there clustering or shelling of the constituents. This is a more general question than just catalytic systems and has applicability to many small cluster problems where normally immiscible systems can be forced to mix or order when confined to small volumes.

EXAFS analysis has provided useful information for these systems; due to the small scattering cross-section and large beam sizes of x-rays, the systems have only been studied as ensemble averages.
Characterization and Catalytic Properties of CuOx/CeO2 Nanocomposite Particles
Authors: Skårman B , Nakayama T , Niihara K , Wallenberg LR
Published: July 2020

Cerium dioxide (ceria) is known for its excellent oxygen storage capacity (OSC) and redox properties. Addition of the transition metal oxide CuOx, improves the low-temperature oxidation activity of ceria by a synergistic mechanism. It has been shown that copper oxide on the high energy CeO2{001}surface, is exceedingly more efficient than on the statistically dominating lowenergy {111} surface for obtaining a high catalytic conversion rate of CO to CO2.:To investigate morphology and composition effects, in a situation which is closer to an industrial catalyst, we have produced nanocomposite particles in the CuOx/CeO2 system with different composition, size, and nanostructured morphology (Fig. la-d) utilizing the inert gas condensation (IGC) technique.

The samples were characterized in a JEM 4000EX HRTEM, and a JSM-840A SEM, interfaced with a Link AN 10000 EDS system. The specific surface area was measured using the adsorption of N2 (BET method).
Microcharacterization of New Platinum Catalysts for Hydrosilylation Reactions
Authors: Chen Wei , Allard Lawrence F , Dinh Paul C , Tzou Ming-Shin , McIIwrath Kevin
Published: July 2020

Organofunctional silanes are the key intermediates for production of silicon polymeric chemicals. Traditionally, platinum catalysts on carbon support materials have been used for these hydrosilylation reactions. The efficiency of the current commercial Pt/C catalyst is not very satisfactory, so a catalyst of platinum on aluminum oxide support was developed to accelerate the reactions. The Pt/Al2O3catalyst greatly increases both reaction and conversion rates. However, the acidic nature of the supporting material is sometimes undesirable. Recently, a new class of platinum-copper bimetallic catalysts has been developed at Dow Corning, using co-deposition techniques with platinum chloride and copper chloride precursors. The bimetallic catalysts have also demonstrated significantly improved on hydrosilylation reaction efficiency and rates. The activity, selectivity, and stability of the catalysts are related to their structural properties, including catalyst particle size, size distribution, and particle composition. The knowledge of catalyst structures are, therefore, very important for understanding the performance of the catalysts and for optimizing production processes.
Video Microscopy: An Innovative Tool to Visualize the Kinetics of Gas-Phase Olefine Polymerization with Heterogeneous Catalysts
Authors: Tesche B , Knoke S , Korber F , Fink G
Published: July 2020

Introduction

Conventional methods to determine polymerization kinetics rely on a measurement of the monomer consumption or on calorimetric measurements. All these methods are integral methods and they are not appropriate to determine the kinetic of individual catalyst particles. Reichert and coworkers have invented video microscopy as a tool that allows the direct determination of polymer growth in gas-phase butadiene polymerization with heterogeneous catalysts.

Results

We present the direct measurement of polymer growth in gas-phase propene polymerization under industrial process conditions by means of video microscopy.The key-element of our equipment is a window autoclave that allows working with pressures up to 150 bar in the temperature range of 0 °C to 120°C. to insure inert atmosphere the reaction chamber is heated under high vacuum conditions before it is loaded with catalyst in a glove box. The reaction temperature is controlled by means of a temperature fluid slope inside the autoclave wall. to start the polymerization monomer gas is introduced to the reactor. We use a black eloxed aluminum disk as support for the catalyst grains.
High Resolution TEM Studies On Palladium, Rhodium Nanoparticles
Authors: José-Yacamán M , Marín-Almazo M , Ascencio JA
Published: July 2020

The field of catalysis is one of the most important areas of the nano-sciences for many years. in deed the goal of having a catalyst, with the maximum active area exposed to a chemical reaction, has produced enormous amount of research in nanoparticles. Particularly, the metal nanoparticles study is a very important field in catalysis. Electron Microscopy is one of the techniques that have played a mayor role on studding nanoparticles. Since bright field images, dark field techniques, to the high-resolution atomic images of nanoparticles and more recently the High Angle Annular dark field images or Z-contrast. However this technique provides only indirect evidence of the atomic arrangements on the particles. High Resolution Electron Microscopy (HREM) still appears as a very powerful technique to study nanoparticles and their internal structure. Among the most interesting metals to study is the palladium, which acts for instance as excellent catalyst for hydrogenation of unsaturated hydrocarbons and has many other applications such as environmental catalysts.
Important Issues on Crystal Size Measurement of Catalysts
Authors: Chan Ignatius
Published: July 2020

A large number of papers have been published on using HREM to characterize the crystal structure and defects of catalysts. While such work is important to advance the scientific understanding of catalysis, the bulk of daily analytical work of an industrial catalyst microscopist focuses on analyzing the morphological features of the catalysts. That is, to find out the shape, the size, and the distribution of various phases. in the case of heterogeneous catalysts, the same information is needed for the catalytic metal particles. Ultimately, the goals are to correlate the performance of the catalyst with the size and morphology of the phases or particles. These types of information are often critical element in a patent.

Unfortunately, very little attention has been paid to properly and quantitatively describe crystal shapi crystal size, and size distribution. It is common to find in the literature, statements such as “the crystal size of this sample was 0.5 microns” or “the sample contains elongated crystals of 0.5 microns”.
Knowledge Discovery in Automotive Catalysts Using Microstructural Characterizations
Authors: Chen Ann E , Lowe-Ma Charlotte K
Published: July 2020

Automotive catalysts are regularly examined using several methodologies such as X-ray fluorescence (XRF), X-ray powder diffraction (XRD), wavelength dispersive spectroscopy (WDS), and analytical electron microscopy (AEM) since no single analytical technique is capable of fully characterizing and measuring changes in morphology and chemistry that occur in emission system materials with use. Each analytical technique provides a specific piece of information, such as elemental weight percentages, phase identification, or spatial distribution of elements. However, in aggregate too much information from too many different specimens is often present, making assimilation and processing difficult. A computerized method using data mining techniques could greatly improve the quality of the interpretation and allow discovery of trends that are not readily apparent. However, finding an appropriate method of combining the disparate types of information is a challenge

The first step was to collect and archive the data in a relational database. This task comprised a large percentage of the development process since the data are initially created in several locations and must be collected, cleaned, and stored.
Applications of the SESAM in Materials Science
Authors: Sigle Wilfried , Zern Achim , Hahn Kersten , Krämer Stefan , Eigenthaler Ulrike , Rühle Manfred
Published: July 2020

SESAM stands for "Sub- eV -sub- Ångstrøm -Microscope". The aim of the project is to develop a TEM/STEM which combines the advantages of both types of instruments. The SESAM project is based on three development stages, specifications of which are shown in Table 1. in the final stage an information limit below 1Å and an energy resolution of 0.2 eV is strived for.

Compared to previous energy-filtering microscopes SESAM I is equipped with a 2nd order corrected energy filter [1]. Due to the high transmissivity [2] large scattering angles up to 150mrad at ΔE=20 eV are accepted by this filter which can be used in electron diffraction experiments. A diffraction pattern of amorphous SiBCN ceramic is shown in Fig.l together with a profile. Since the diffracted intensity can be integrated over 2π, high statistical accuracy is achieved even at a moderate exposure time (10s). in energy-filtered imaging large specimen areas are imaged isochromatically.
The New EF-TEM with OMEGA and FEG
Authors: Oikawa T , Kawasaki M , Kaneyama T , Ohkura Y , Naruse M
Published: July 2020

Recently, energy filtering technique in the transmission electron microscopy (EF-TEM) is becoming widely used in both materials and biological science.

In this paper, newly developed EF-TEMs for both 200 kV (JEM-2010FEF) and 300 kV (JEM- 3100FEF) are introduced. Figure 1 shows appearances of the instruments. Those instruments have a field emission gun and an OMEGA type spectrometer.

The features of JEM-2010FEF and JEM-3100FEF EF-TEMs are as follows [1,2]:

1. 3 pre-filter lenses and 3 post-filter lenses are used.

Additional intermediate lens is employed for covering filtered images in low magnification range from x200 - x 1,500,000 magnification for JEM-2010FEF, x200 - x2,000,000 for JEM- 3100FEF. in diffraction mode, from 200 mm - 2,000 mm in camera length for JEM- 2010F, 200 mm- 1,500 mm are covered for JEM-3100FEF.

2. Large energy dispersion.

The energy dispersion is 1.2 μm/eV at 200 kV and 0.85 μm/eV at 300 kV.
First Results of a Monochromized 200KV TEM
Authors: Tiemeijer PC , van Lin JHA , de Jong AF
Published: July 2020

FEI is currently finishing the construction of a monochromized 200kV (S)TEM which aims at 0.1 eV resolution in Electron Energy Loss Spectroscopy (EELS). This requires improvement of the 200kV supply, improvement of the EELS spectrometer, and the incorporation of an electron beam monochromator. This microscope will be delivered to the National Centre for High Resolution Electron Microscope at the University of Delft.

The present 200kV supply contributes 0.2 eV to the energy resolution because of its instabilities, drift and high frequency ripple. in order to reduce this, mechanical as well as electrical damping elements are being added, and sources of cross-talk between the high frequency generator and the high tension are eliminated. in this paper, we present preliminary results obtained with a standard 200kV supply; we expect to present results of the improved 200kV supply at the conference.

The resolution of a present-day standard 200kV spectrometer is now typically 0.4 eV. in order to improve on this, GATAN has developed a HR-EELS spectrometer for the monochromized TEM.
Development of Line Analysis and Real-Time Elemental Mapping System in Stem Equipped with a Two-Window Energy Filter
Authors: Kaji K , Aoyama T , Taya S , Isakozawa S
Published: July 2020

The ability to obtain elemental maps processed by using inelastically scattered electrons in a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM) is extremely useful in the analysis of materials, and semiconductor devices such as ULSI’s and GMR heads. Electron energy loss spectra (EELS) also give useful information not only to identify unknown materials but also to study chemical bonding states of the objective atoms. Hitachi developed an elemental mapping system, consisting of a STEM (Hitachi, HD- 2000) equipped with a two-window energy filter (Hitachi, ELV-2000), and performed realtime conventional jump-ratio images with nanometer resolution by in-situ calculation of energy-filtered signals [1]. Additional function of acquiring EELS along any lines on specimen has been developed in this system to investigate the energy loss near edge structure (ELNES).

Figure 1 shows a schematic figure of the two-window energy filter, consisting of two quadrupole lenses for focusing and zooming spectra, respectively, a magnetic prism spectrometer, a deflection coil and two kinds of electron beam detectors.
Novel Approaches in Spectrum-Image Analysis
Authors: Thomas PJ
Published: July 2020

It is now becoming increasingly more commonplace to acquire three-dimensional EELS data sets, whether by parallel acquisition of a linear series of spectra to form an EELS spectrum-image, or by discretely sampling energy-loss space through a series of energy-filtered images to build an EFTEM image-spectrum. These data sets can contain large amounts of both spectral and spatial information, and, as a result, the distinction between the two acquisition modes is becoming increasingly blurred. Accordingly, approaches are required that facilitate both the techniques developed for EFTEM and EELS analyses, in order to obtain optimal information from the acquired data.

An example of such an approach is illustrated by means of characterisation of a Mn and Fe rich intermetallic particle in a cast aluminium alloy (Figs. a-f). A continuous EFTEM image-series was acquired from 0-800 eV loss, using a CM300 FEGTEM equipped with a 2k Gatan Imaging Filter.
Four-Dimensional Dielectric Property Imaging of Low-K Materials for Copper Metallization Using Electron Spectroscopic Imaging Series
Authors: Lo SC , Chen F-R , Kai JJ , Chang L , Ding Peijun , Chin Barry , Chen Fusen
Published: July 2020

EFTEM has become a very useful tool in characterizing material properties, because it allows studying local chemical and electronic properties of a specimen with nanometer level spatial resolution. There are two spectroscopic imaging methods have been established to obtain both the spatial and the spectra information, I (x, y, ΔE), which can be quantitatively evaluated. One technique, as known as spectrum-image method, is based on scanning the electron beam across the sample to acquire the EELS spectrum with two-dimensional information. Conversely, the other method retrieves the spectra in a specific position from a series of energy loss images, as known as imaging-spectrum method. The spectrum-image method can be achieved with better energy resolution, however, a long acquisition time. Compared to spectrum-image method, which acquires a series of spectrum with scanning probe, the advantage of imaging-spectrum method is the capability of simultaneously recording abundant information in a series of maps.
The Spatial Distribution of Water in Soap
Authors: Aitouchen A , Shi S , Libera M , Misra M
Published: July 2020

Soap bars can be viewed as pseudo-binary two-phase composites consisting of solid particulate suspended in water-enriched medium. Understanding the size and the distribution of the two phases in a bar is of interest to cosmetic industry. Electron Energy Loss Spectroscopy (EELS) combined with Scanning Transmission Electron Microscope (STEM) has been used to perform water mapping in certain biological systems. Here we report preliminary analysis of soap-water matrix in a soap bar by employing EELS and spectrum imaging techniques.

Thin slices of soap bars containing 13% water (as measured using Karl Fischer titrator) were frozen using a Leica high-pressure freezer (EM PACT). 200 nm thick cryo-sections were cut at -160°C. The frozen sections were cryo-transferred at -170°C to a Philips CM20 FEG electron microscope equipped with the Gatan CCD spectrometer ENFINA interfaced to an Emispec Vision system for digital control and data acquisition.
Inner Shell Edge Jump Ratios in Electron Energy Loss Spectrometry
Authors: Rez P , Menon NK
Published: July 2020

There has been considerable interest in recent years in simulating the complete electron energy loss (EELS) spectrum to help the analyst make suitable judgments on experimental parameters such as collection angles and acquisition times. The spectrum is characterised by edges that arise from the excitation of inner shell electrons to the first available empty state. The edge threshold is approximately given by the inner shell binding energy. Each edge sits on the background of the tails of all the edges from inner shell excitations of lower energy (see Figl). The background from plasmons decays very quickly with energy and even the broadest plasmon makes a negligible contribution to the intensity for losses above about 150eV. The visibility of an edge (and also the detectability of the corresponding element) can be related to the intensity of the edge compared to the background although it is more common to use the jump ratio, which is the ratio of the intensity in the region after the edge E+B to the intensity of the background in the edge region, B.
Current Limits in Predicting Eels Fine Structure
Authors: Muller D A , Neaton J , Haman D R
Published: July 2020

Electron energy loss spectroscopy (EELS) probes electronic excitations of a solid on the atomic scale. The widespread availability of first-principles calculations has lead to an explosion of theoretical calculations of EELS spectra. Agreement between theory and experiment is generally reported to be good at the typical energy resolutions in commercial microscopes of 0.7-1.3 eV. However a brief survey of the X-ray absorption literature suggests that the anticipated introduction of monochromators, along with improvements in energy stability, and spectrometer resolution will unmask many more effects that cannot be predicted as precisely as they can be measured.

The shape and binding energy of a core excitation is determined by both the ground state electronic structure (initial state effects) and the reponse to the excited electron-hole (final state effects) (Fig. 1). Errors in the initial state, such as the systematic errors in band gaps (and hence band offsets) are inherent in the local density approximation eigenvalues used to simulate EELS spectra.
Core Hole Effects on Eels Near-Edge Fine Structure in Semiconductors and Insulators
Authors: Duscher Gerd , Buczko Ryszard , Pennycook Stephen J , Pantelides Sokrates T
Published: July 2020

Electron energy-loss spectroscopy (EELS) is now a standard tool to investigate the local chemistry and bonding of defects in solids. to first order, the energy thresholds of the ionization edges in EELS spectra are determined by the identity of the element [1], while small shifts are induced by different bonding coordination and charge states [2]. The shapes of ionization edges in EELS spectra reflect the local bonding environments. We present first-principles calculations that incorporate electron-hole interactions and are in excellent agreement with experimental data obtained with X-ray absorption spectroscopy (XAS) and EELS. The superior energy resolution in XAS spectra and the new calculations make a compelling case that core-hole effects dominate core-excitation edges in all of the materials investigated: Si, SiO2, MgO, SrTiO3 and SiC. These materials differ widely in their dielectric constants leading to the conclusion that core-hole effects dominate all core-electron excitation spectra in semiconductors and insulators.
Electron Energy Loss Spectroscopy (EELS) of GaN Alloys and Quantum Wells
Authors: Keast V J , Sharma N , Kappers M , Humphreys C J
Published: July 2020

In the last 6-7 years there has been considerable experimental and theoretical interest in GaN and its alloys for use in light emitting applications. GaN is a direct gap semiconductor with a bandgap at ∼ 3.4 eV. When alloyed with in and/or Al the bandgap can be tuned to any wavelength ranging from UV to red. to further the development of GaN based devices, reliable methods are required to measure and predict the optical and electronic properties. EELS is one of the few techniques that can study these properties with high spatial resolution (< 1 nm) if a small electron probe is used, such as that in a scanning transmission electron microscope (STEM). High spatial resolution is necessary as, to improve efficiency, devices are normally based on quantum well structures.
Microwave Tissue Procesing: History and SEM Techniques
Authors: Demaree R S
Published: July 2020

Microwave-assisted processing of biological samples began with Mayers. Subsequently, many investigators reported using microwave ovens for various aspects of biological sample processing for light microscopy (LM) and/or transmission electron microscopy (TEM.) The use of ice-encased fixation and water-immersion resin polymerization marked the beginning of rapid, reproducible microwave-assisted processing techniques.

Mcrowave protocols are now often used for LM and TEM processing. Examples include paraffin embedding for LM, in situ hybridization, decalcification, immunological staining plus clinical studies and research projects for TEM.

Recently my lab has begun to microwave process biological samples for scanning electron microscopy (SEM.). We fix, dehydrate and dry with hexamethyldisilazane in less than 1 ½ hours. The only part of the process not utilizing microwave assist is the final 15 minute drying step in a conventional oven.
Examination of Structural Differences in Gill Vasculature Among Some Batiod Elasmobranchs Using Corrosion Casting and SEM
Authors: Sherman RL
Published: July 2020

Classic studies of gill vasculature indicate the gross anatomy of elasmobranch gills is similar in most species, and in general, resembles those of teleosts. However, studies of fine gill structure examining arterio-arterial pathways in several species of batoid elasmobranchs (Order: Rajiiformes, Suborder: Myliobatoidei) have reported some structural differences. These differences include the presence, in urolophids (Urolophus jamaicensis, U. mucosus, U. paucimaculatus), of 1) a tip channel, possibly an extension of the afferent filament artery that runs along the top of the filament corpus cavernosum, and 2) a vascular arcade, a vessel which connects the afferent filament arteries of a hemibranch near the tip of each filament (FIG. I). Until recently these structures were believed to be unique to the urolophids as they were not previously found in either rajids (Raja erinacea, R. clavata) or the shark Scyliorhinus canicula. Animals of mixed species and sexes were collected, perfused, and acrylic casts made of the circulatory system.
Self-Assembly of Dynamin
Authors: Danino Dganit , Hinshaw Jenny E
Published: July 2020

Dynamin is a large GTPase essential for various intracellular processes such as synaptic vesicle recycling, caveolae internalization and trafficking into and out of the Golgi. It is also involved in receptor-mediated endocytosis, and is believed to assemble at the necks of clathrin-coated pits and assist in pinching vesicles from the plasma membrane upon GTP binding and hydrolysis.

Purified recombinant dynamin self-assembles into rings and spirals in low salt conditions [1]. A dynamin mutant lacking the c-terminal proline rich domain (APRD) also assembles into rings and spirals, however unlike wild type dynamin APRD constricts in the presence of GTP analogous such as GMP-PCP [2] or GTPγS. to explore differences in the behavior of the wild type and mutant dynamin we dialyzed them into different salt solutions containing various types of nucleotides and studied their assembly over time using negative staining and cryo-TEM.
The Power of Freeze-Fracture Technique in Electron Microscopy
Authors: Papahadjopoulos-Sternberg B
Published: July 2020

In the early 1960s, concerns about artifacts in preparing biological material for electron microscopy led to a new technique whereby samples are rapidly frozen, fractured under high vacuum, the fractured surfaces shadowed and replicated with a thin metal-carbon coat, and the cleaned replica examined in a transmission electron microscope. Pioneered by Moor and Muhlethaler subcellular structures are revealed with extraordinary three-dimensional clarity at near-molecular resolution. Furthermore, it was observed and proven at model systems as well as biological membranes that lipid bilayers split along their hydrophobic interior during freeze-fracture procedure. Therefore, freeze-fracture electron microscopy (FFEM) has the unique advantage of accessing the hydrophobic interior of biological (FIG.l, 5 and 6) as well as artificial bilayers (FIG. 2, 4, 5, and 6). Here it permits study of pattern generated by intrinsic proteins as well as lipids (FIG. 1 and 2).
The Development of a Holey Metal Oxide Support Film for High Temperature “Ex-Situ” Tem Oxidation Studies
Authors: Kliewer CE , Varon J , Malek A , DeMartin GJ
Published: July 2020

Transmission electron microscopy (TEM) has traditionally served as an important tool for understanding the physical properties of many materials. Recent improvements in “ex-situ” techniques have further strengthened the role of TEM as a unique characterization method.

The use of ExxonMobilfs dedicated reactor system for studying metal oxidation at moderate temperatures has been reported. However, high temperature oxidation studies have been limited by the use of holey carbon support films, which oxidize and disintegrate during these experiments. Consequently, a new method was developed to replace the holey carbon support film with a holey metal oxide support film that both maintains its structural integrity during high temperature oxidation and remains electron transparent.

The new support film was prepared using a commercially available, holey carbon coated TEM grid as a template (Figure 1). An Al metal film (∼10nm thick) was deposited onto the holey carbon coated side of the TEM grid using a magnetron sputtering system.
Preparation/Dispersion of Small Particles for TEM Study
Authors: Foo Kit h , Chiou W-A , Ishikawa A , Fukushima K , Meshii M
Published: July 2020

Small particles such as clay minerals, because of its large surface area to volume ratio and their high chemical activity on the particle surface, when added to composites affects (and often enhances) the physical, chemical and mechanical properties of materials immensely. As a result, there is a need to develop a method of characterizing these particles individually. However, physical dispersion of these particles can be very difficult, since they tend to agglomerate to reduce the high surface energy. Disperants of various sorts could be used to disperse/stabilize the system, but they could compromise/damage the integrity of the inherent state of these small particles. This paper presents a comparison study of preparing/dispersing small clay particles for electron microscopy research, and also represents the first report of cryo-microscopy of clay minerals.

Two types of smectites, namely a montmorillonite with cation exchange capacity (CEC= 140) and a saponite (CEC=42) were used for this study.
Thickness Measurements of DLC Films by EELS and Electron Holography
Authors: Musashi T , Ikematsu Y , Shindo D , Nakamura N , Oikawa T
Published: July 2020

Diamond-like carbon (DLC) has been used as thin films to protect the surface of magnetic disks in hard disk drives. Recently, in order to improve the recording density of the hard disks, DLC films need to be thinner than 10 nm in thickness. Therefore, it is necessary to develop the accurate thickness measurement technique for thin DLC films. in this study, to establish the thickness measurement technique for DLC films using electron energy-loss spectroscopy (EELS) and electron holography, we estimate the mean free path for inelastic scattering (ƛp) and the mean inner potential (U0). Through the evaluation of ƛp and U0, we compare the accuracy of EELS and electron holography on thickness measurement of DLC films.

The DLC films in this study are deposited on silicon wafers by chemical vapor deposition (CVD), sputtering and ion beam deposition (IBD) methods.
Adhesion Strength of Cu-Ni Multilayered Coatings on Optical Fibers
Authors: Lin Yuli , Hwang Li-Jang
Published: July 2020

Optical fibers have been extensively employed in a variety of fields. However, the need of high strength, excellent resistance to moisture permeation and tolerance to heat becomes apparent when such optical fibers are used in nuclear power plants and chemical plants in particular. Plastic coatings as conventional made of optical fibers cables would be replaced by the optical fiber coated with layers of metals.

The adhesion of coating to substrate is a critical property of any coating system for mechanical integrity and environmental protection of the substrate. For example, the corrosion protection of the metal coated optical fibers is highly depend on the adhesion of the coatings, if adhesion is poor, the extent of deterioration of the substrate by environmental factors (humidity, corrosive gases, etc.) is greatly accelerated. The durability and longevity of a coating required that its adhesion is to be maintained [1].
Magnetic Domains and Domain Wall Pinning in Nanocrystalline Ni-P
Authors: Zhang JP , Guo YX , Speck JS
Published: July 2020

Magnetic domain structures in a Ni-5at%P alloy have been examined using Lorentz microscopy in Fresnel mode in a JEOL 2010TEM. with electron diffraction and high resolution electron imaging, the Ni-P alloy material is seen to be of FCC structure and composed of nanometer-sized grains (< 4nm in diameter), which is about 2 orders less in size than that of a single magnetic domain.

The TEM specimen was prepared using jet polishing method. Before introducing the specimen into the microscope, the objective lens was turned off in a free lens control mode to ensure that the domain structures in the specimen remain unaffected. The objective mini-lens was used to perform Lorentz imaging with out-focus method.

Stripe domains were observed. The width of these stripes is about 0.2 micron. But the length of these domains varies, sometime up to several microns. The stripe domains are grouped, which are near parallel one to the other.
Analytical Electron Microscopy of V-4%Ti-4%Cr Alloys
Authors: Bentley J , Pint B A
Published: July 2020

An important aspect in the consideration of V-4%Ti-4%Cr alloys as structural materials for proposed fusion reactors, especially for weldments, is the sensitivity of mechanical behavior to oxygen content. Following a 1-h anneal at 1200°C, sheet specimens were subjected to extended (16h to 43h) anneals at 500°C in 5 to 8 x 10-6 torr oxygen, followed by an homogenization vacuum anneal of 100 h at 600°C. Weight gains indicated ∼200 to >1400 wppm oxygen doping. Specimens were also subjected to an additional vacuum anneal for 4 h at 950°C. Specimens were prepared by standard double-jet electropolishing for TEM characterization with a Philips CM30 (LaB6) equipped with a Gatan Imaging Filter (GIF), and with a Philips CM200FEG equipped with Oxford EDS, GIF, and Emispec Vision integrated acquisition system.

Following oxygen doping and homogenization, high concentrations of nanoscale G.P.-zone-like clusters on ﹛001﹜ were observed in the matrix, with a ∼200-nm-wide precipitate free zone (PFZ) at grain boundaries.
The Determination of the Orientation Relationship Between Primary and Eutectic Aluminum in A.Cast 319 Aluminum Alloy
Authors: Donlon WT , Zindel JW
Published: July 2020

Cast 319 aluminum is an important automotive alloy used for engine blocks and cylinder heads. in order to “optimize” the as-cast microstructure and physical properties, a detailed understanding of its solidification behavior is required. One aspect of the solidification behavior which is not well understood is the mechanism by which aluminum and silicon in the eutectic regions nucleate. Figure 1 is an optical micrograph which identifies the aluminum dendrites, the Al-Si eutectic region, iron intermetallics, and Al2Cu particles. Dahle, Hjelen & Arnberg have utilized electron backscattered diffraction (EBSD) patterns, obtained with an SEM, on several Al-Si alloys to examine the orientation relationship between the aluminum in the eutectic to that of the surrounding aluminum dendrites. in this investigation transmission electron microscopy (TEM) is used to provide a more detailed examination of this eutectic structure while selected area diffraction (SAD) provide similar data to EBSD on the orientation relation between regions of primary and eutectic aluminum.
Phase Transformations in β- Phase Cuzn Single Crystals Induced By Ion Irradiation
Authors: Tolley Alfredo J , Sanchez Esteban A
Published: July 2020

The high temperature equilibrium β phase in Cu-based alloys has a disordexed bcc structure. Its stability at high temperatures is due to the large amplitude ﹛0 ζ ζ)﹜ <0 ζ ζ> soft mode which provides a large vibrational entropy. This stability decreases with temperature as the entropy term in the Gibbs free energy becomes smaller. However, by quenching it is possible to retain the β phase avoiding decomposition by diffusion controlled transformations. in ternary β phase Cu-Zn- Al alloys, ion irradiation at room temperature has been reported to induce a phase transformation to a close packed structure or to produce γ phase precipitates. in order to further study the tendency of the β phase to decompose into other phases at room temperature, ion irradiation experiments in binary Cu-Zn single crystals were carried out using a beam of 30 keV Ar ions. The changes in the microstructure were examined using transmission electron microscopy.
Medium-Range Order in Metallic Glasses Studied by Fluctuation Microscopy
Authors: Li Jing , Gu Xiaofeng , Hufnagel T C
Published: July 2020

Atomic structure on the 1-2 nm scale, often referred to as “medium-range order” (MRO), is of great importance for understanding the properties of disordered materials. It is, however, difficult to adequately characterize medium-range order. Fluctuation microscopy is a newly developed TEM technique that has successfully been employed to characterize MRO in amorphous semiconductors. The predominance of highly directional covalent bonds leads naturally to the presence of MRO in amorphous semiconductors. For metallic glasses, however, the bonding is primarily metallic and nondirectional. Thus, it is not readily apparent whether MRO would exist, or whether fluctuation microscopy is a useful tool for studying the structure of metallic glasses. in this work we report the use of fluctuation microscopy to identify differing degrees of MRO in Zr-based bulk metallic glasses; the MRO depends on the alloy content and the method of TEM specimen preparation.
Phase Identification in Melt Spun Mg-1.5%wtCa-6%wtZn Alloy Using Electron Diffraction and HREM
Authors: Jardim PM , Solórzano IG , Vander Sande JB , You BS
Published: July 2020

In recent years there has been a significant increase in magnesium use as a structural material. Applications include aerospace and automotive industries as well as appliances and sporting goods. The most attractive feature about magnesium alloys is related to their low density. However, their mechanical properties require improvement to surpass the specific strength of the high strength aluminum alloys. The purpose of the present paper is to report the crystal structure determination of the precipitates found in the alloy Mg- 1.5%wtCa-6%wtZn produced by melt spinning.

The as solidified alloy was analyzed by means of Transmission Electron Microscopy(TEM), Scanning Transmission Electron Microscopy (STEM) and Energy Dispersive X-ray Spectroscopy (EDS). The crystal structure of the new precipitate observed was determined by means of comparison of experimental and simulated selected area electron diffraction patterns (SADP) and High Resolution Electron Microscopy (HREM) images. The simulations were obtained using the software EMS.