bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Microstructural Study of Hot Pressed and Reactive Sintered Beta-Silicon Nitride Coated with Alumina
Authors: Ghosh G , Vaynman S , Fine M E 
Published: July 2020

Abstract
Silicon nitride-based or SiAlON ceramics are increasingly being considered for many engineering applications due to their low density, high strength, and high modulus. For many engineering applications SiAlON ceramics are required to have, among many other properties, both high fracture toughness and good tribological properties. Typically, an interlocking microstructure consisted of β-Si3N4 and/or β'-SiAlON grains is produced, by sintering Si3N4 with desirable additive(s), with a residual glassy or partly crystalline grain boundary phase. The fracture process in such a microstructure is predominantly intergranular, the cracks tend to follow a tortuous path. However, the presence of an intergranular glassy phase causes rapid deterioration of properties at temperature above the glass transition temperature. Therefore, in order to improve high-temperature properties of these ceramics it is desirable to minimize, and if possible to eliminate, the intergranular glassy phase. Particle coating techniques are receiving increasing attention as they are convenient ways of incorporating sintering aids/dopants more uniformly than conventional powder blending method.
Cathodoluminescence Investigation of Electron Irradiation Damage in Insulators.
Authors: Stevens Kalceff MA , Phillips MR , Moon AR 
Published: July 2020

Abstract
Cathodoluminescence (CL) is the luminescent emission from a material which has been irradiated with electrons. Cathodoluminescence microanalysis (spectroscopy and microscopy) in an electron microscope complements the average defect structure information available from complementary techniques (e.g. Photoluminescence, Electron Spin Resonance spectroscopy). CL microanalysis enables both pre-existing and irradiation induced local variations in the bulk and surface defect structure to be characterized with high spatial (lateral and depth) resolution and sensitivity. This is possible as electron beam parameters such as the beam energy, may be varied to finely control the penetration depth of the incident electrons and hence the local volume of specimen probed.
Irradiation with charged and neutral energetic radiation produces defects in radiation sensitive materials. The energetic electron beam in an electron microscope may also induce defects in the specimen. Cazaux has characterized the electric field produced by electron irradiation of a insulator with a conductive surface coating
Electron Microscopy Study of Surface Layers of The French Son68 Nuclear Waste Glass Formed During Vapor Phase Alteration At 200 °C
Authors: Gong WL , Wang LM , Ewing RC 
Published: July 2020

Abstract
The objective of this study was to simulate the aqueous corrosion of the nuclear waste glass over extended periods of time using vapor phase alteration by which reaction progress of glass corrosion is accelerated to form a characteristic suite of secondary alteration phases. In this study, extensive SEM/EDS, AEM, and HRTEM have been performed on the French SON68 waste glasses which were reacted in saturated water vapor at 200 °C for 908, 1013, and 1021 days, respectively. In order to study chemistry and microstructure of surface layers, TEM specimens were prepared in cross-section using the ultramicrotomy slicing technique. In this process, small chunks containing the surface layer and a thin layer of unaltered glass were broken off from the sample surface and each of these chunks was then embedded in resin to form a block. Finally, thin sections, approximately 50-90 nm thick, were microtomed from these blocks and were transferred to holey carbon coated copper grids.
High-Resolution Transmission Electron Microscopy of Defects in Todorokite (Oms-1)
Authors: Turner S , Buseck PR 
Published: July 2020

Abstract
Todorokite is a manganese oxide mineral that occurs in widespread terrestrial and marine deposits. It is a major component of manganese nodules which occur in large quantities on ocean and some lake floors (&gt;1012 tons). Todorokite has been linked to the presence of potentially mineable transition elements in manganese nodules. Todorokite is an octahedral molecular sieve material and has been termed by some in the chemical community as OMS-1. Many of the properties of synthetic and natural varieties have been characterized and potential applications include use for adsorption, as oxidation catalysts and in electrochemical devices.
The todorokite structure consists of a framework of MnO6 octahedra that are edge- and corner-linked to form tunnel structures. Several tunnel structures have been found in naturally occurring todorokite ranging from the most basic 3×3 structure to 3×8 and larger structures. Large cations and water occur in the tunnel interiors.
Oxidation Mechanism of Ferritic Stainless Steel Used for Catalytic Converters in Automotive Exhaust Systems Studied by TEM
Authors: Liu Ping , Andersson Jan 
Published: July 2020

Abstract
Emission of pollutants from automobiles is regarded as one of the major causes of air pollution in many cities around the world. However, the pollutants could be almost eliminated by using catalytic purification of exhaust gas, thus making a better environment. The metallic material for catalytic converters made of ferritic stainless steel, Sandvik 0C404 (20.0 Cr-5.0 Al-Fe balance in wt % plus the addition of rare earth elements), offers a number of advantages over a ceramic one: better thermal conductivity, higher mechanical strength and toughness, thinner walls, larger effective area, greater catalytic capacity, smaller and more flexible design; better resistance to thermal shock. The formation of a homogenous A12O3 layer at high temperature is essential for providing corrosion resistance in such applications because of its high corrosive environment.
A prolonged oxidation of ferritic stainless steel Sandvik 0C404 at 1100 °C resulted in an accelerated oxidation (as schematically illustrated in Fig.l).
Characterization of Adhesive-Primer Penetration into Porous Oxides Formed on Anodized Aluminum Using Energy Electron Loss Spectroscopy (Eels)
Authors: Cole J I , Brien D O' , Qian M , Fisher R M 
Published: July 2020

Abstract
The purpose of this investigation is to evaluate the effects that relatively minor changes in phosphoric acid anodizing (PAA) parameters (voltage, temperature, time) have on oxide morphology and the subsequent penetration of an applied adhesive-primer into the porous oxide. This preliminary study examines two cases, one in which industry-standard PAA parameters have been followed, and a second in which the PAA parameters are slightly above industry limits.
Baseline PAA parameters have been developed in the aerospace industry from extensive empirical testing in order to maximize adhesive bond strength and durability in the presence aggressive environments. It has been noted that for effective mechanical strength of structurally bonded elements, penetration of the adhesive primer into the porous oxide formed by an anodizing pre-treatment is critical. Verifying primer penetration is somewhat problematic due to the high spatial resolution required to both structurally and chemically characterize an oxide film on the order of one micron in thickness.
Microstructural Effects on the Scc Morphology of Alloy 600 in Deaerated Water
Authors: Burke MG , Symons DM 
Published: July 2020

Abstract
Previous studies on the stress corrosion cracking (SCC) behavior of Alloy 600 forgings revealed a correlation between the SCC susceptibility and thermomechanical processing (specifically the final annealing temperature). (1) Detailed microstructural analyses using analytical electron microscopy (AEM) techniques showed that the materials containing dendritic-type intergranular M7C3 carbides were also more resistant to SCC initiation and propagation. This type of analysis has been extended to the evaluation of a 0.062 wt.% C Alloy 600 plate in three conditions (as-received, and heat-treated for 1 week at 982°C and water-quenched, and annealed for 24h at 1075°C and furnace-cooled). Tests were performed in PWR environments using fatigue precracked compact tension (CT) samples. In addition, detailed microstructural analyses using light optical metallography (LOM) and AEM were performed to fully characterize each material condition. The SCC fracture morphology was evaluated using scanning electron microscopy (SEM).
LOM examination of the as-received material indicated a “good” microstructure, with carbide-decorated grain boundaries as well as intragranular carbides.
Correlation of Measured Thermal Conductivity to a Functionally Graded Material's Microstructure
Authors: Phelps John , Slifka Andrew , Filla James 
Published: July 2020

Abstract
Functionally Graded Materials (FGMs) are used in a number of applications as a protective barrier to extreme environments. One such application of FGMs is to protect metal parts from high temperature environments. FGM coatings are plasma spray deposited onto surfaces of both simple and complex machined parts. Knowing the thermal conductivity of the FGM coating allows engineers to effectively develop high temperature designs with accurate estimates of heat transfer and thermal loading.
In this study, a FGM made by Caterpillar, USA, was measured with our steady state thermal conductivity measurement apparatus. The sample measured is a 10 layer graded coating using a Metro* 461 bond coan4 to a Metco* 205 ceria-yittria stabilized zirconia, with a Ni-Co-Cr-Al-Y metal grading. Figure 1 shows a plot of the thermal conductivity (W/m*K) as a function of temperature (K) for this material. The sudden drop in thermal conductivity at approximately 1073K was totally unexpected
Recent Developments in Fluorescence Spectroscopy: Light Quenching and Multi-Photon Excitation with Tir, Two-Color Two-Photon Excitation and Long Lifetime Probes
Authors: Lakowicz Joseph R 
Published: July 2020

Abstract
Fluorescence spectroscopy is presently enjoying explosive growth due to new experimental capabilities. In this talk we summarize some recent advances which can have applications in cell biology and imaging.
We show that evanescent illumination at one wavelength and incident angle, coupled with light quenching at a second wavelength and incident angle (Figure 1), can be used for selective excitation of fluorophores located up to 5000 Å into the aqueous phase. The use of combined evanescent wave excitation and evanescent wave quenching could provide selective excitation of fluorophores in the cytoplasmic region of cells. We also reported the first experimental observation of two-photon excitation using the evanescent wave resulting from total internal reflection. Two-photon excitation of the calcium probe Indo-1 was demonstrated by the quadratic dependence on intensity (Figure 2) as well as by the anisotropy and time-resolved fluorescence measurements.
Two-photon excitation is routinely performed using a single wavelength. We recently observed two-photon excitation of organic fluorophores with two different wavelengths, a phenomenon we refer to as two-color two-photon excitation.
Pulsed Laser Imaging Techniques: Calcium and Exocytosis in Excitable Cells.
Authors: Fernandez JM 
Published: July 2020

Abstract
A rapid Ca++ signal is known to be the main trigger for exocytosis in excitable cells. However, its mode of action is unknown. Recently, it has become clear that the spatial distribution of a Ca++ stimulus is important for exocytosis. To investigate this question we have developed a novel instrument capable of imaging Ca++ gradients in patch clamped cells. We have equipped a standard fluorescence microscope with a CCD camera and an image processing station. This combination can generate a thin section view of the fluorescence of a single cell. We have equipped this microscope with a pulsed laser illumination system. The distribution of intracellular calcium can be obtained by exciting the Ca++ indicator dye (e.g., rhod-2) with a brief laser pulse [300 ns long at 525 nm ], then an image can be formed with the light emitted by the dye. by synchronizing the laser pulse with a depolarizing stimulus in a patch-clamped chromaffin cell loaded with the fluorescent Ca++ indicator rhod-2, we could easily obtain snapshots of the Ca++ distribution at known times after a stimulus.
Design of a Wide Field High Sensitivity Imaging System for Quantitative Analysis of CGHA Micro-Arrays.
Authors: Sudar Damir , van Vliet Lucas , Clark Steve , Segraves Rick , Lockett Stephen , Albertson Donna , Gray Joe , Daniel Pinkel 
Published: July 2020

Abstract
Comparative Genomic Hybridization (CGH) is a quantitative technique for determining relative copy numbers of DNA sequences in whole-genomic test samples. In conventional CGH, test DNA labelled with one fluorochrome and reference DNA labelled with a spectrally different fluorochrome are hybridized to metaphase chromosomes. by measuring the ratio of intensities of the two fluorochromes, a relative copy number of sequences in the test DNA can be calculated for each point along each chromosome. While this approach is very useful for rapid surveying of the entire test genome, the spatial and dynamic resolution are compromised by the dense packing of DNA in the metaphase state. CGHa (array-based CGH) uses spots of cloned DNA arrayed onto a microscope slide which represent the entire genome or interesting sections thereof. Spatial resolution and dynamic range are now only limited by the size of the clones used. See the abstract by Pinkel et al. for more detail.
We designed an imaging system for analyzing fluorescence signals from micro-arrays containing targets on the order of 100μm in diameter spaced at similar intervals.
Two-Photon Laser Scanning Confocal Microscopy
Authors: Cheng PC , Pan SJ , Shih A , Liou WS , Park MS , Watson T , Bhawalkar J , Prasard P 
Published: July 2020

Abstract
Two-photon fluorescence microscopy has become an important research tool in both biological and material sciences. The technique uses long wavelength, typically in the near IR, as the excitation light to obtain shorter wavelength fluorescence (e.g. visible light). Because of the low linear absorption coefficient of most biological and polymeric specimens, this technique allows deeper penetration of the excitation beam, achieving optical sectioning to a depth of 250μm or more into the specimen. As a result of the quadratic dependency of the two-photon induced fluorescence to the excitation intensity, the fluorescent emission and photobleaching are limited to the vicinity of focal spot. This capability of addressing a specimen’s 3D space allows exciting possibilities in biological researches, such as 3D photobleaching recovery experiment.
Two-photon confocal fluorescence microscopy is ideal for the study of thick biological and material specimen in 3D. For example, Figure 1 shows a three-dimensional isosurface rendered image of a vascular bundle from a maize stem.
Near Edge X-Ray Absorption Fine Structure (NEXAFS) Microscopy: Chemical Analysis at Sub Visible Spatial Resolution
Authors: Ade H 
Published: July 2020

Abstract
Infrared, Raman, and fluorescence/luminescence microspectroscopy/microscopy in many instances seek to provide high sensitivity compositional and functional information that goes beyond mere elemental composition. This goal is shared by NEXAFS microscopy, in which Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy is employed to provide chemical sensitivity and can be relatively easily adopted in a scanning transmission x-ray microscope (STXM). In addition to compositional information, NEXAFS microscopy can exploit the dependence of x-ray absorption resonances on the bond orientation relative to the linearly polarized x rays (linear dichroism microscopy). For compositional analysis, NEXAFS microscopy is analogous to Electron Energy Loss Spectroscopy (EELS) in an electron microscope. However, when utilizing near edge spectral features, NEXAFS microscopy requires a considerable lower dose than EELS microscopy which makes it very suitable to studying radiation sensitive materials such as polymers. NEXAFS has shown to have excellent sensitivity to a wide range of moieties in polymers, including sensitivity to substitution isomerism.
Deltascan, a Light Microscope Imaging System for Examining Birefringent Materials.
Authors: Lewis JG , Glazer AM 
Published: July 2020

Abstract
DELTASCAN is a new light microscopy imaging system developed and built in the Department of Physics, Oxford, UK. [1] It is able to separate out the contrast seen in a ‘cross-polars’ image into three components, | sin δ | (a function of the optical retardation), φ (the orientation of a section of the optical indicatrix) and Io (the transmittance). These three variables are plotted as separate coded colour images. With the present computer and apparatus the data is collected, processed and the images simultaneously drawn in approximately 40 seconds.
DELTASCAN has an optical setup [2] based around a polarising microscope (Figure 5). The intensity through this optical setup can be shown to have the form:
I = Io[1 + sin2(ωt−ϕ)sin δ] (1)
where ω = frequency of the analyser, φ = orientation of cross section of the indicatrix and, δ = relative retardation which is related to a samples birefringence by δ = 2πΔnL/λ.
Full Spectrum Raman Imaging of Glasses and Other Materials
Authors: Morris Michael D , Jestel Nancy L , Christensen Kenneth , Shaver Jeremy M 
Published: July 2020

Abstract
Several spectral bands or regions often are required for contrast generation to utilize the full power Raman imaging for mapping compositional or physical property variations. To achieve this, it is most efficient to use a high throughput imaging spectrograph with a two-dimensional detector operated in pushbroom mode as a line imager. Despite data from several bands, univariate data reduction techniques are inadequate when characterizing complex materials. Multivariate statistical procedures, such as factor analysis, are useful for defining weighted sums of intensities from many Raman shifts (frequencies) and this in turn expresses chemically or structurally useful contrast.
We illustrate this approach with silicate and aluminosilicate glasses. In most cases, no single band can unambiguously identify a particular glass composition. If the glass is heterogeneous, then localized compositional and structural differences may be detected by small changes in several bands, all arising from motions of assorted Si-O moieties.
Infrared Microspectroscopy in Earth and Planetary Science: Recent Developments, Including In Situ High-Pressure, High-Temperature Techniques
Authors: Hofmeister AM 
Published: July 2020

Abstract
Vibrational spectroscopy is used in Earth science for both quantitative and qualitative analysis. This report focuses on infrared (IR) spectroscopy, although similar efforts are on-going in Raman spectroscopy.
Qualitative studies utilize the fact that the vibrational spectrum is a characteristic of a material: hence comparison to a set of standards allows for identification of the phase. Most of these types of studies in Earth science involve macrosamples, but measurements of microsamples from meteorites are on interest in order to identify the structure of SiC inclusions and the type of organic compounds in interplanetary dust. As most of these samples are micron sized, which is below the diffraction limit for the mid-IR, the approach has been to compress the sample using a diamond anvil cell (DAC) into a disk of sub-micron thickness, adhere the sample to a KBr plate, and to subsequently remove the disk from the DAC and obtain spectra with the aid of an FTIR microscope.
Application of Epma Area Analysis To Thickness Measurement of Thin-Films
Authors: Takakura M , H.Takahashi  , Kondo Y , Okumura T , Nielsen C 
Published: July 2020

Abstract
Electron Probe Micro Analyzer (EPMA) uses the characteristic X-ray for analysis. Therefore the depth of analysis area is spread to a few micrometer. It is difficult to make the quantitative or state analysis of surface thin-film. However, it is possible to measure the thickness of thin-film by using the X-ray intensity ratio between the film and bulk standard specimen under an assumed X-ray depth distribution function. In this paper, a known composition thin-film was measured by EPMA and the result was applied to thin-film area analysis.
Film thickness was measured as mass thickness (ρz) by the intensity ratio of the characteristic X-ray intensities between the thin-film and bulk standard. As the X-ray distribution function ϕ(ρz) the model due to Packwood and Brown1) was used, which is written as.

(1)
An error is thought to exist in the thickness calculation because the backscattering yield near the interface is different when the difference in the atomic numbers is large between the thin-film and the substrate.
Direct Measurement of Sarcoplasmic Reticulum Calcium Content Following Isoproterenol or Caffeine Treatment
Authors: Sweet Wendy E , Moravec Christine S 
Published: July 2020

Abstract
The major storage site for calcium in cardiac muscle is the sarcoplasmic reticulum (SR). It has been shown using indirect methods that the amount of calcium stored in the SR can be altered by various agonists and anesthetics. The only technique to date which directly quantifies the amount of calcium in the SR is Electron Probe Microanalysis (EPMA). Using EPMA, an accurate measurement of the size of the SR calcium store can be made following treatments with known agonists.
Isoproterenol (ISO) causes an increased inotropic response in cardiac muscle via the (3-adrenergic pathway. When ISO binds to the (β-receptor on the plasma membrane, it causes the activation of Protein Kinase A (PKA) through a cascade of events. PKA phosphorylates the sarcolemmal calcium channels causing an increase in the rate of calcium influx. PKA also phosphorylates Tnl, which sensitizes the myofilaments to calcium, thereby increasing the rate of calcium release from the myofilaments.
Subcellular Composition Based On Light-Element EELS
Authors: Leapman RD 
Published: July 2020

Abstract
Recent work on biological electron energy-loss spectroscopy (EELS) in the analytical electron microscope has focused on measuring concentrations of the important elements, calcium and phosphorus. Analysis of the light elements, for which EELS was originally thought to be best suited, has so far not yielded much useful information from biological specimens. Whereas low-loss fine structure has been analyzed successfully to measure distributions of water and protein in frozen-hydrated cells, core-edge fine structure cannot be recorded at sufficiently low dose to obtain useful chemical information. However, the atomic ratios of the light elements (carbon, nitrogen and oxygen) obtained from EELS are less dependent on electron dose. Together with sulfur (in proteins) and phosphorus (in nucleic acids, phospholipids and phosphates) these ratios can help determine the types and proportions of compounds that are present at the subcellular level. Here we re-examine the potential for making these kinds of measurements.