bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomic Scale Analysis of Oxygen Vacancy Segregation At Grain Boundaries in Ceramic Oxides
Authors: Browning N D , Buban J P , Ito Y , Klie R F , Lei Y 
Published: July 2020

Abstract
The properties of ceramic oxides being developed for such varied applications as fuel cells, ionic transporting membranes, high-Tc superconductors, ferroelectrics and varistors are dominated by the presence of grain boundaries. Key to controlling the electronic properties of the grain boundaries in these materials is a fundamental understanding of the complex relationship between structure, composition and local electronic structure. The ability to characterize and directly correlate these parameters on the atomic scale is afforded by the combination of Z-contrast imaging and electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM). Furthermore, the recent development of in-situ heating capabilities in the JEOL 201 OF STEM/TEM permits atomic resolution analysis to be performed at elevated temperatures and the interactions of grain boundaries with the oxygen vacancies determined.
Figure 1 shows an example of the type of experiment that can be performed using these methods.
Quantitative HREM: Reliable Structure Determination of Grain Boundaries in SrTiO3
Authors: Gemming Thomas 
Published: July 2020

Abstract
High resolution transmission electron microscopy (HREM) is an excellent experimental method to image grain boundary structures with atomic resolution. The advantage of the method is the short exposure time of only about one second that is needed to record an image. Other methods like Z-contrast imaging require much longer exposure times and are therefore much more prone to specimen drift during recording. However there is the remaining difficulty to HREM that the evaluation of experimental images is not straightforward and a thorough analysis of the images is necessary in order to deduce quantitative information with small error bars of only a few pm (10-15m). A second inherent difficulty common to all atomic resolution imaging techniques is that the information is retrieved from a very small area of a specimen. The question arising from that is: can we nevertheless be sure to obtain a representative answer to a “real world” material science problem? A positive answer to this question is given by the investigations presented here.
Microscopic Analysis of Twin Grain Boundaries in Alumina
Authors: Nufer S , Marinopoulos AG , Fabris S , Elsässer C , Kurtz W , Rühle M 
Published: July 2020

Abstract
Extended structural defects in α-Al2O3 (alumina), a technologically important, complex ceramic material were quantitatively analyzed with respect to grain boundary segregation, atomic and electronic structures using spatially resolved electron energy-loss spectroscopy (EELS), energy dispersive X-ray spectroscopy (EDS) and first-principles local-density-functional (LDFT) calculations. in this study the results of analytical investigations will be compared with the outcome of LDFT calculations.
The analytical measurements were performed with a dedicated scanning transmission electron microscope (TEM) VG HB501UX, operating at 100 kV and with a typical beam diameter of lnm. For the spatially resolved EELS a parallel electron energy-loss spectrometer (Gatan model 666) with an energy resolution of better than 0.8 eV was used. For the chemical analysis an EDS system (Noran-Gresham with a Si(Li) detector and a Norvar window) was applied. The detection limit of the EDX system for measuring interface excess is in the range of 0.3 atoms/nm2.
UHV-TEM/REM Study of Palladium Silicide Islands Grown on Silicon (111) 7×7 Surface
Authors: Takeguchi M , Mitsuishi K , Liu J , Zhang Q , Tanaka M , Furuya K 
Published: July 2020

Abstract
The growth of self-organized nanoislands and nanowires on a substrate has been extensively studied with a view to fabricating the new functional materials and advanced electric devices. in the present work, Pd silicide islands and wires grown on Si (111) 7x77×7surface were observed in situ by ultrahigh vacuum transmission and reflection electron microscopy (UHV-TEM/REM). Pd was deposited on Si (111) 7×7 surface at about 700 K using an electron beam evaporator attached to the column of a UHV microscope. Two kinds of specimens were prepared: a &lt;111&gt; oriented rectangular specimen with a thin area, whose (111) top surface was observed by plan viewed TEM, and a &lt;110&gt; oriented bulk rectangular specimen, whose (111) side surface was observed by REM
Figure la shows a REM image of Si (111) 7×7 surface. An incident electron beam is directed from the top to the bottom of the figure, which is foreshortened in the beam direction.
Impurity Effects on Shear Adhesive Strength of Tungsten Carbide Thermal Spray Coatings on Steel
Authors: Naidu Seetala V , Garber James D , Glassc Gary A 
Published: July 2020

Abstract
We have used High Velocity Oxy-Fuel (HVOF) thermal spray coating process to obtain tungsten carbide coatings on steel. It is important to control the powder quality and surface roughness of the substrate in the thermal spray coating process to obtain good adherence. The adhesive strength is greatly effected by the interfacial impurities. Most commonly used in the thermal spray industry is Al2O3 grit abrasive for good surface roughness of steel substrate to produce anchor patterns for the coating. The previous studies indicated that some fine Al2O3 particles are trapped in the rough surface grooves during this process. The ring shear test method, described previously, appears to give the most accurate results on shear adhesive strength. The ring shear strength test was comprised of a 0.02” thick and 0.25” wide ring coating on a 1” diameter cylindrical substrate rod. This rod is placed in a disk with a cylindrical hole of the rod size and an incremental pressure is applied on the rod.
Characterization of Gan/Sapphire Interface and the Buffer Layer by TEM/AFM
Authors: Shea B , Sun-Paduano Q , Bliss D F , Callahan M C , Sung C 
Published: July 2020

Abstract
Interest in wide band gap III-V nitride semiconductor devices is increasing for optoelectronic and microelectronic device applications. to ensure the highest quality, TEM analysis can characterize the substrate and buffer layer interface. Measurements taken by TEM reveal the density of dislocations/cm2 and the orientation of Burger's vectors. This information allows for changes to be made in deposition rates, temperatures, gas flow rates, and other parameters during the processing.
The GaN/sapphire samples grown at AFRL were produced in two consecutive steps, first to provide a thin buffer layer, and the other to grow a lum thick epitaxial film. Both growth steps were prepared using metallic organic chemical vapor deposition (MOCVD) in a vertical reactor. Buffer layers were prepared using a range of temperatures from 525 to 535°C and with a range of flow rates and pressures in order to optimize the nucleation conditions for the epitaxial films.
Microtexture Studies of Extruded Aluminum Using Electron Backscatter Diffraction
Authors: Claves S R , Misiolek W Z , Williams D B 
Published: July 2020

Abstract
Electron backscatter diffraction (EBSD) is a powerful tool used for the characterization of deformed microstructures and has been successfully applied to determine the microtexture of specific regions of bulk samples. The work presented here is a continuation of previous analyses investigating the microstructural response of 6xxx aluminum extrudates to complex die designs. Specifically, the grain orientations across longitudinal welds produced from porthole dies is being studied.
Previous work examined the cross section of a sample that was extruded using a specially designed die that would position the weld in the center of the part. This specimen, shown in Figure 1, is a simple, solid, rectangular shape produced under controlled conditions. The other sample being studied, seen in Figure 2, was part of an actual extrusion run, conducted with typical industrial parameters. This sample is part of a complex shape that uses a porthole die to produce hollow sections.
Specimen Thickness Effects on EBSD Patterns in the Sem
Authors: Michael J R 
Published: July 2020

Abstract
Electron backscatter diffraction (EBSD) in the SEM has become a widely used technique for both automated orientation mapping and the identification of unknown crystalline phases. Despite the rapidly growing use of this technique for the above applications, there has been relatively little fundamental research concerned with determining the thickness of the surface layer that generates the EBSD pattern. EBSD patterns are related through reciprocity to electron channeling patterns. Based on this assumption the thickness of the surface layer that an EBSD pattern is generated in is 2 or 3 extinction distances. Extinction distances at low SEM voltages (10-20 kV) are quite short. Thus, EBSD patterns are generated in very thin surface layers. This paper will discuss the results of a study of the information depth of EBSD in the SEM.
Previous research has attempted to determine the information depth of EBSD by obtaining patterns from samples that have had layers of other crystalline or microcrystalline material deposited on the surface.
Which is Better for Protein Imaging: Phase Contrast TEM or Annular Dark Field STEM?
Authors: Rez P 
Published: July 2020

Abstract
In a landmark paper Henderson compared X-ray, neutrons and electrons for protein structure determination. He showed that electron microscopy should be superior to X-ray or neutron diffraction in terms of dose for a given resolution. in addition he presented a theoretical analysis to determine the smallest size molecule whose structure could be determined by phase contrast microscopy. Although he qualitatively considered amplitude contrast mechanisms and concluded they were inferior to phase contrast, no explicit numerical analysis was performed. It has been implicitly assumed that bright field phase contrast imaging is the optimal technique for imaging small biological molecules. Protein specimens are usually embedded in some medium such as ice or glucose. Since they must give a very low contrast it seems reasonable to expect that bright field techniques for these weakly scattering objects would be inferior, given that a weak signal is sitting on large background.
HRTEM and EELS Study for Superconducting and Non-Superconducting (Cu,Cr)-1212 Cuprates
Authors: Anan Y , Asaka T , Kurami H , Hatano J , Tsutsumi S , Kimoto K , Matsui Y 
Published: July 2020

Abstract
The crystal structures of high temperature superconducting cuprates consist of alternative stacking of charge-reservoir (CR) block and conduction block. in case of YBa2Cu3Oy, (YBCO), CR block contains one-dimensional Cu(I)-O chain and BaO layers, and conduction block contains two-dimensional Cu(II)O2 planes and Y layers. YSr2Cu3Oy (YSCO), where Ba-sites of the YBCO are replaced by Sr completely can be obtained only by high-pressure synthesis. However, by replacing Cu(I) partly by Cr, YSr2Cu3-xCrxOy can be obtained even under ambientpressure conditions. The compound YSr2Cu2.8Cr0.2Oy (x=0.2) is non-superconductive, but, superconductivity is induced by partial replacement of Sr-sites with Ba; the compounds with YSr2-xBaxCu2.8Cr0.2Oy (x≤0.5) is non-superconductive, but the compound with x≥1.0 is superconductive. in order to obtain the structural information about the transition to superconducting phases, the effect of the Ba substitution is investigated by transmission electron microscopy (TEM).In the present study, the compounds with YSr2-xBaxCu2.8Cr0.2Oy (x=0-1.5) are examined by high resolution TEM (HRTEM) and electron energy-loss spectroscopy (EELS) to elucidate structural and electrical modification induced by Ba-substitution.
Tem Study of Nano-Crystals in Strontium Ion-Implanted Cubic Zirconia
Authors: Zhu S , Wang LM , Wang S X , Lian J , Ewing RC 
Published: July 2020

Abstract
Yttria stabilized zirconia (YSZ) is an important oxygen ion conducting solid electrolyte. YSZ is used in oxygen sensors, oxygen pumps, and fuel cells. Perovskite-type oxides of general formula ABO3 are also of fundamental significance due to their electrical and electro-optical properties. SrZrO3 is a promising material- for application as protonic conductor. in this paper, we present electron microscopy analysis of the formation of SrZrO3 nano-particles in the top surface of YSZ single crystal after ion implantation. These results demonstrate a unique process for obtaining mixed-conducting oxides in the surface layer of YSZ. in addition, it is important to study the behavior of strontium in YSZ because of the potential application of YSZ as an inert fuel matrix for “burning“ excess plutonium in nuclear reactors.
400 keV strontium ions have been implanted into YSZ at room temperature to a fluence of lxl021 ions/m2.
The Charge Ordering Behavior of Colossal Magnetoresistive (CMR) Layered Compounds La2-2xSr1+2xMn2O7 (x = 0.5 ∼ 0.6)
Authors: Luo Z P , Miller D J , Mitchell J F 
Published: July 2020

Abstract
In colossal magnetoresistive (CMR) materials, large changes in physical properties stem from the interplay between charge ordering (CO) coupled with orbital and magnetic orderings. Thus detailed microstructural studies are important in understanding these changes in physical properties. In-situTEM observation is a very useful approach to study CO transitions in these CMR compounds. We have recently studied the CO behavior of the three-dimensional perovskite Nd1/2Sr1+2xMnO3. in this work, we report the CO of two-dimensional naturally layered compounds La2-2xSr1+2xMn2O7 (327 phase), where x is the hole doping level and varies from 0.5 to 0.6 in this work.
Thin foil TEM specimens were prepared from polycrystalline bulk samples by conventional thinning and ion milling method at liquid N2 temperature. The in-situ TEM work was carried out in the Electron Microscopy Center at Argonne National Laboratory using a Philips CM30 with a liquid N2 cold stage, and a Hitachi H-9000 with liquid He cold stage.
Effect of High Heating Rates on Microstructure of Alumina and Aluminum Titanate Ceramics
Authors: Stanciu Lia A , Groza Joanna R 
Published: July 2020

Abstract
In conventional sintering, high heating rates are often used to enhance densification and reduce grain growth. The essence of this concept is to use fast heating rates to favor densification instead of grain growth, if the activation energy for densification is greater than that for grain growth. At low temperatures, surface diffusion is the most effective sintering mechanism but is associated with grain coarsening. Therefore, a high heating rate may take the system for densification at high temperatures before surface diffusion causes grain growth and decreases the sintering driving force. Field activated sintering technique (FAST) is a newly developed sintering method, which applies an external electrical field to enhance densification. The method applies pulsed and continuous current to powders subject to a modest pressure (&lt; 100 MPa). Electrical current application enables fast heating rates. The sintering cycles are very short, typically less than 10 minutes for full densification.
Toughening of Brittle Materials by Dislocation Cells
Authors: Saka H , Moon W-J , Horiuchi S , Uchimura S 
Published: July 2020

Abstract
Many attempts have been made to improve the fracture toughness of brittle materials such as ceramics. Most of the methods developed so far make use of metallurgical processes, for example, phase transformation, refining of grains, formation of composite materials. However, these methods can not be applied universally to brittle materials which do not have such a useful metallurgical processes.
Moon and Saka (1) recently showed that the fracture toughness Klc of a YAG single crystal the sub-surface of which is damaged by micro-Vickers indentation at room temperature, followed by annealing at high temperatures is improved by a factor 2 from 1.13 to 2.26MPam1/2. The fracture toughness Klc was evaluated by measuring the length of cracks which initiate at the corner of Vickers indentation(2). Transmission electron microscopy of the subsurface reveals the healing of cracks introduced by room-temperature indentation and formation of dislocation cells. The thin foil specimens were prepared using a focused ion beam(FIB) technique(3).
Variation of Size and Alignment in Carbon Nanotubes by Changes of Growth Condition
Authors: Provencio Paula P , Siegal Michael P , Overmyer Donald L 
Published: July 2020

Abstract
Carbon nanotubes have previously been grown on Ni coated glass, aligned vertical to the substrate over a multi-centimeter square area1. Under vacuum, the aligned nanotubes were grown below 666° C (strain point of the best display glass) by plasma-enhanced hot filament, chemical vapor deposition. It was found, the size and alignment of the nanotubes could be varied by changing the dwell time and the thickness of the catalytic Ni layer by plasma etching. in more recent, ongoing studies, the size of carbon nanotubes is varied by changing the growth temperature and dwell time under acetylene/nitrogen atmosphere using chemical vapor deposition onto W and Ni coated Si.
Multiwall carbon nanotube films are grown using a thermally-activated chemical vapor deposition process. Thin Ni catalyst layers are sputtered onto W-coated Si(100) and reduced in a 600°C CO anneal. Nanotubes then grow at temperatures ranging from 630 - 790°C in an acetylene/nitrogen mixture.
The Expression Patterns of Semaphorin Genes 3b, 4a, 4f, and 6c in the Lymphoid Tissue of Mice Found Through in Situ Hybridization
Authors: Beheshti Sayeh , Matthes David 
Published: July 2020

Abstract
The semaphorin family consists of a set of secreted and transmembrane proteins which contain a domain of approximately 500 amino acids called the semaphorin domain. The investigation of the role of semaphorin proteins in the nervous system has established them as chemorepellents of axons. Recent studies have identified the semaphorin proteins on the surface of cells in the immune system and in the genomes of two lytic viruses. These strongly suggest the possible involvement of the semaphorin proteins in the immune system. This study aims to understand the expression patterns of four semaphorin genes, Sema3B, Sema4A, Sema4F, and Sema6C in the lymphoid tissues of wild type mice. These proteins were chosen to represent the three subfamilies III, IV, and VI. The first family contains secreted proteins which have immunoglobulin domains (III), the second contains transmembrane proteins which have immunoglobulin domains (IV), and the third contains transmembrane proteins which do not have immunoglobulin domains (VI).
The Effects of Light Intensity on Plastid Organization of the Toxic Dinoflagellate Prorocentrum Hoffmanianum: A Correlated Tem and Fluorescence Microscopy Study
Authors: Schuette S , Schmitt S , Tindall D 
Published: July 2020

Abstract
Toxic dinoflagellates gained notoriety for their devastation to coastal and island economies, causing damages totaling in the millions of dollars that included losses of harvestable resources, clean-up costs, as well as cancellation of holiday reservations in popular tourist/recreational areas.3 These red tide blooms sparked an urgency for obtaining information pertaining to the dynamics of toxin production, but understanding the mechanisms of toxin production have proven to be difficult to pin point. This study tested the hypothesis that cells grown under various light intensities undergo structural and compositional changes and served as a basis for future biochemical studies of Prorocentrum hoffmanianum.
We examined ultrastructural changes to the chloroplast in cells from monocultures of Prorocentrum hoffmanianum grown in three different light intensities, via a transmission electron microscope and a fluorescent light microscope. The full or normal growth chamber intensity of ca. 5000 lux represented the control group referred to as the full light treatment.
Modified Flat-BED Scanner for Macroscopic Study of Large Specimens
Authors: Cheng Wayne Y , Cheng Ping-chin , Cheng Mai-Ing , Walden David B 
Published: July 2020

Abstract
The field number of the objective lens limits the field of view in a conventional compound microscope; even at very low magnification, the microscope does not allow observation of large pieces of specimen at once. This made the observation of organs and large pieces of tissue sections inconvenient. in the course of studying the development of maize stem, we encountered the need of digitizing large hand sections for 3D reconstruction. Splicing a series of images that are taken at different positions to form a montage is not acceptable, because the jointed image suffers from mismatch due to lens distortion. Considering the resolution needed in our study, one alternative is to use a consumer flatbed scanner designed for a personal computer. in order to adapt the conventional scanner for wet tissue scanning, an Acer 620TPC flatbed scanner, equipped with a trans-illuminator, was modified (FIG 1).
The Role of Microscopy in Quality Control, Litigation and Forensic Studies of Hides, Skins and Leather
Authors: Cross Robin H 
Published: July 2020

Abstract
The economic importance of animal hides and skins as the source material for the natural leather industry is significant world-wide, and in some countries of the developing world the livelihood of a large proportion of the population depends upon it. Consequently, it is understandable that anything affecting the quality of the source material and the finished product has major economic, industrial and sociological significance. It is also inevitable that a product that is so widely-used in many ways by most of the population will become an important source of evidence in forensic investigations.
Quality control procedures in the leather industry involve monitoring the progress of the hides and skins from the growth stages of the animal, through the slaughter, storage, transportation, curing, tanning and finishing processes, to the sale and distribution of the finished product. There are many factors during these stages that can affect quality of finished leather, amongst the most important of which are mechanical and parasite damage during growth, biodeterioration and mechanical damage between slaughter and curing, mechanical, heat and chemical damage during curing, tanning and finishing.
Characterization of Biodegradation of Fiber Cement Shingles by Scytonema Sp. Using Optical and Scanning Electron Microscopy
Authors: Reine Barbara A , Murphy Colin 
Published: July 2020

Abstract
Fiber cement roofing shingles from condominiums in Hawaii were examined for deterioration using optical and scanning electron microscopy. The product has a 50 year warranty and had been in service since 1994. Shingle samples were taken in August and September, 2000 after a growing volume of reports of roofing deterioration were received by the condominium association. Close-up visual inspection confirmed that the roof areas showing deterioration were covered with a black growth. Roofing samples from areas exhibiting deterioration, areas with no deterioration, and new material were compared by microscopy.
Examination of the black growth by optical microscopy revealed it to be primarily the Cyanobacterium, Scytonema sp.This is a filamentous organism found from the Arctic to the Antarctic, and is common to Oahu and Maui.’ Other organisms observed to be present are Chroococus sp., Gloeocapsa sp., Aphanocapsa sp., Oscillatoria sp.,a very few Trebouxia sp.and lichens.