bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of Nanometer-Sized Metal Clusters
Authors: Bradley Steven A 
Published: July 2020

Abstract
Characterization of nanometer-sized particles dispersed onto a porous support is critical for understanding performance of heterogenous catalysts. The electron microscope offers a unique capability for measuring the cluster size and chemistry of these nanometer-sized metal clusters. Cluster size and size distribution can be readily determined by using high angle annular darkfield or z-contrast microscopy. However, as catalysts become more complex with additional components that modify the metal activity, determination of the chemistry of individual clusters could be interesting. Conducting such studies is not straightforward and some of the problems associated with making such measurements will be discussed using model catalysts and a VG HB 601UX dedicated STEM.
Problems associated with this type of measurement can include the instability of the small metal particle under the intense, focused electron beam as well as spurious signals from the area surrounding the region of interest.
Quantitative Characterization of Particle Shape of FCC Catalysts by Image Analysis
Authors: Li Zhengmin , Xu Xingzhong , Yang Jinghe , Xu Xiuling , Yu Weijun , Yue Xiuying 
Published: July 2020

Abstract
In the fluidized catalytic cracking (FCC) unit of oil refinery, the attrition resistance of FCC catalysts is affected by particle shape. Although some sophisticated methods, such as Fractal dimension and Fourier analysis, have been introduced to particle shape analysis, most of them are used to assess the shape of individual particle. It is difficult to be used as a means of powder quality control in the course of application and production of FCC catalysts. So three shape factors, i.e. Short/long ratio (S), Roundness (R) and Concavity (C), are applied to characterize them in three different aspects.
A small quantity of FCC catalyst powders were spread on a glass slide M and a thin layer of glue was spread on another glass slide N, then all the particles on slide M were sprinkled on slide N by vibrating manually up and down, in the meantime moving back and forth more than 10 times.
Energy-Filtered Imaging of Colloidal Cobalt Metal Particles
Authors: Disko MM , Popplewell J , Grady KO’ , Hutchings J 
Published: July 2020

Abstract
Supported transition metal particles are often used as heterogeneous catalysts. Elemental mapping with energy-filtered transmission electron microscopy (EFTEM) offers distinct advantages over conventional TEM and x-ray analysis for these systems. Thickness maps, metal identification, support identification, and direct imaging of oxide layers all represent key new information made possible with EFTEM. Energy-filtered transmission electron microscopy with an omega filter has been used to show Ni, Cu and Cr distributions in an alumina-supported catalyst. in this paper we look at analogous cobalt particles from a colloidal suspension supported on a carbon film.
Energy-filtered TEM maps were obtained using a Gatan Image Filter at 200 kV integrated with an FEI CM200FEG microscope. The colloidal cobalt particles have a nominal diameter of 10 nm, providing an excellent model system when supported on thin amorphous carbon supports. Figures 1 - 3 show cobalt L23, oxygen K and elastic micrographs of partially oxidized cobalt particles (native oxide present after drying).
Direct Observation of Changes of the Metal-Substrate Interface Chemistry in Supported Heterogeneous Catalysts
Authors: Klie RF , Browning ND , Disko MM 
Published: July 2020

Abstract
The heterogeneous catalytic system Pt/SiO2 is widely used in “three-way” catalysts, because of its highly selective catalytic reduction of NO by hydrocarbons at low operating temperatures. Although used effectively for more than a decade, in recent years it has become clear that the core phenomena of heterogeneous catalysis can occur at interfaces. in the work presented here, we seek to better understand the role of the atomic and electronic structure of interfaces in making particular reactions facile and moderating the stability and selectivity of a catalytic system.
We investigate model supported platinum catalysts by atomic resolution Z-contrast imaging and EELS using a 200 kV STEM/TEM JEOL2010F with a post column GIF. The combination of these techniques allows us to obtain direct images of the metal particle and its interface with the supporting SiO2, and to correlate that with the modulation of the Si L-edge fine structure.
High Angle Annular Dark Field (HAADF) STEM Tomography of Nanostructured Catalysts
Authors: Weyland M , Midgley PA , Thomas JM 
Published: July 2020

Abstract
Progress in the design of catalysts based on nanoparticles supported within a mesoporous silica framework requires structural analysis at high spatial resolution. While bulk analysis by X-ray diffraction and EXAFS can give the structure of active sites they are unable to determine their relative positions and local physical structure. Some success has been achieved using a combination of STEM ADF imaging and EDX mapping to elucidate such structures but these results are limited to giving 2D projections of 3D arrangements. The need exists therefore to analyse specimens in full 3D. A suitable approach is electron tomography where the 3D structure is reconstructed from a tilt series of 2D projections. in conventional electron tomography a tilt series is acquired using bright field (BF) TEM. However the large beam current means such an approach generally cannot be used on specimens based on a mesoporous silica framework as beam damage can develop rapidly.
Surface Structures of Catalytic Oxides
Authors: Erdman N , Pless JD , Poeppelmeier KR , Marks LD 
Published: July 2020

Abstract
Transition metal oxides have been studied extensively over the last few decades, due to their electro optical and catalytic properties.The overall properties of these oxides and the heterostructures that can be built on them depend upon the surface structure, composition and morphology. However, the available information on the surface structures of transition metal oxides is scarce and often contradictory. Knowledge of the atomic structure of the catalytically active surfaces and of the adsorbed reactants and intermediates under in-situ reaction conditions is crucial for an understanding of catalytic oxidation at the molecular level, and will subsequently create possibilities for faster development of new catalysts, improve their performance on industrial level, and lower the costs associated with processing. The objective of the current work is to develop and apply the available experimental (UHV chambers, UHV-HREM, catalytic treatment chamber) and computational techniques (Direct Methods analysis and multislice simulations of electron diffraction data) to improve understanding of catalytic phenomena under various environmental conditions.
Truly Quantitative EELS Imaging - Let’s Not Settle For Just Pretty Pictures Anymore
Authors: Hunt John A 
Published: July 2020

Abstract
The term “quantitative“ means many things to many people. in imaging its value is often discounted to mean only that a more intense region can be said to have more of what is being measured than a less intense region. Others may be more stringent and require an approximately linear relationship between the measured property and image intensity. (This is most often the case in EFTEM and spectrum imaging) Some specimens contain internal references (such as elements with a known stoichiometric relationship) that are sufficient to get to a true concentration calibration for an image. However, in EELS imaging this still doesn’t allow us to get an understanding of our errors and rarely is it helpful in determining detection or quantification limits.
A competent high-school chemistry or physics student could tell us that a quantitative measurement includes both a measured value and an estimate of its error.
’A Priori’ synthesis of electron energy-loss spectra for detection limit quantification
Authors: Menon N K , Krivanek O L , Hunt J A 
Published: July 2020

Abstract
A software package has been developed that synthesizes entire energy-loss spectra for an arbitrary distribution of impurities embedded in an arbitrary matrix, for user specified sample parameters and acquisition conditions. The simulation of a complete spectrum facilitates the estimation of quantities such as the Minimum Detectable Mass (MDM) or the Minimum Detectable Number of atoms (MDN). This is addressed with particular attention to optimising the acquisition conditions to maximize the detectability and also to estimating the error in a typical EELS quantification. It is envisaged that this approach will have wide-ranging implications for the role of EELS in quantitative microanalysis.
Electron Energy Loss Spectroscopy (EELS) is widely recognized as a microanalytical tool capable of characterizing the elemental composition of materials with nm-level resolution and sensitivity approaching single atoms. Extracting quantitative information from EEL spectra is complicated by the fact that both the cross-sections and the pre-edge background used for inner-shell analysis vary widely.
Results from a New Fast, High Sensitivity, Eels Spectrometer
Authors: Trevor C , Harmon R , Brink H , Hunt J 
Published: July 2020

Abstract
Last year we discussed the performance of a new parallel EELS spectrometer, the ENFINA™. The spectrometer optics have been considerably improved over past designs and the detector changed from a photodiode to a charge coupled device that was designed specifically for spectroscopy. in this work we present application examples that demonstrate some of the capabilities of the ENFINA™.
STEM spectrum imaging requires a spectrometer of high speed and sensitivity if useful data is to be collected in a short period of time. The ENFINA™ spectrometer achieves both of these through a radically improved point spread function, increased sensitivity, and fast detector readout. Useful spectrum images can be acquired in a few minutes. Figure 1 shows a dark-field STEM image of a typical semiconductor. A spectrum image containing 190 x 150 spectra was acquired from within the marked area.
Insight Into the Properties of Functional Materials with Energy Filtered and Analytical TEM
Authors: Botton GA 
Published: July 2020

Abstract
Energy filtered (EF) imaging and energy loss fine structure analysis have now become routine tools to characterize very complex microstructures at high spatial resolution. When combined with energy dispersive x-ray spectroscopy microanalysis in a field emission gun transmission electron microscope (TEM) and with samples prepared by a large array of techniques such as FIB or microtoming, these analytical techniques can tackle real-life and more fundamental problems in materials science. This paper presents some examples of this work that highlight the complementarity of information obtained either from EF imaging, near-edge structures and EDS microanalysis. These examples are taken from work in the development of battery materials for automotive applications and in the study of ultrathin magnetic layers. Other examples of high spatial resolution energy loss fine structure at interfaces of high-K dielectric-Si in interface are shown in elsewhere in these proceedings.
Three Dimensional Energy Filtered Transmission Electron Microscopy (3D-EFTEM)
Authors: Weyland M , Midgley PA 
Published: July 2020

Abstract
Energy filtered transmission electron microscopy (EFTEM) has been developed in recent years to be a highly flexible tool for spatially resolved microanalysis. The basic technique has been extended to allow fully quantitative mapping of single elements, or a large range of elements using an image-spectroscopy approach. All these techniques are still limited by the nature of the TEM as a structure projector; any elemental map is only a 2D projection of what is in reality a 3D structure. A fully 3D approach to EFTEM analysis would offer additional insights into many materials problems and make possible meaningful analysis of certain systems for the first time. Three-dimensional electron microscopy (electron tomography) offers one path for the reconstruction of 3D structures from 2D projections. Although this has been well developed for solving the structure of biological macromolecules and viruses its use in the physical sciences is quite new.
Analysis of the Defect Chemistry at Gd-Doped Ceria Grain Boundaries
Authors: Ito Y , Lei Y , Browning ND , Mazanec TJ 
Published: July 2020

Abstract
Gd3+ doped Ce oxides are very promising candidates as electrolytes for solid oxide fuel cells operating at ∼ 500 °C. For their successful commercial implementation, a full understanding of the defect chemistry in the bulk and at grain boundaries is essential. in particular, the contribution of the grain boundaries to the total ionic conductivity through such effects as the segregation of impurities, dopants and vacancies is of crucial importance. Here the effect of the atomic structure on the local electronic properties, i.e. oxygen coordination and cation valence at grain boundaries of the fluorite structured Gd0.2Ce0.8O2-x ceramic electrolyte is investigated by a combination of Z-contrast imaging and electron energy loss spectroscopy (EELS) in the JEOL 201 OF STEM (operating at 200keV, and aligned for a probe size ∼ 0.2 nm).
Preliminary O K- and Ce M45-edges were acquired from points in the grains (A and B) and grain boundary shown in Figure 1.
Bifurcation Patterns and Branching Exponents in Branchial Vessels in Tadpoles of Xenopus laevis Daudin during Metamorphosis-3D-Measurements from Microvascular Corrosion Casts
Authors: Minnich B , Bartel H , Karch R , Schreiner W , Lametschwandtner A 
Published: July 2020

Abstract
Introduction
Fluid transport systems of organisms [1] in general and the blood vascular system in particular are considered to be optimally designed. From Murray's laws [2] it is concluded that an arterial bifurcation where the diameter of the parent vessel (d0) relates to the larger (d1) and the smaller daughter vessel (d2) according to d0 3 = d1 3 + d2 3 is optimal. Interestingly, existing data predominantly refer to arterial branchings of the fully developed circulatory system of mammals. to the best of our knowledge there are no data available on arterial bifurcations and venous mergings in an initially growing but then regressing tubular system of blood vessels as it is found in the gill filter apparatus of the anuran tadpole where the highly complex three-dimensional vascular network totally disappears at the end of metamorphosis.
The Ultrastructure of the Connective Tissue Matrix is Significantly Improved Using Cryo-Fixation At High Pressure
Authors: Keene D , Tufa S 
Published: July 2020

Abstract
The investigation of connective tissue ultrastructure has historically relied on chemical fixation to stabilize micro architecture. These fixatives are not effective in retaining many matrix molecules, including proteoglycans, and allow precipitation of many other components in subsequent processing steps. The result is a preponderance of open space between matrix components. Cells shrink considerably and a precipitation of molecules in highly concentrated regions leads to artifacts including the lamina lucida and lamina densa of basement membranes. Cryo-fixation at high pressure followed by freeze substitution seeks to immobilize tissue components within vitreous (non-crystalline) ice, which is later substituted with acetone at temperatures below the recrystalization temperature of water. Formation of large ice crystals during any part of the preparation protocol significantly distorts structure and can be recognized in the compound microscope. Recognition of smaller freezing artifacts, including microcrystalline ice, is imperative for interpretation of resulting images.
Recent Advances in Microwave-Assisted Specimen Processing for in-Situ Hybridization
Authors: Sanders Mark A , Gartner David M 
Published: July 2020

Abstract
Co-localization of proteins and nucleic acid sequences by in situ hybridization and immunohistochemistry is frequently difficult as the procedure necessary to detect the target structure of one technique may negatively affect the target of the other. Structural impairments may also limit the application of the two techniques. to overcome these problems we developed a method to perform in situ hybridization and immunohistochemistry on Chromosome spreads, intact cells and semi-thin sections of methyl methacrylate-embedded tissue. Microwavestimulated antigen retrieval, signal amplification by catalyzed reporter deposition, and fluorescent dyes were used for all techniques, yielding high sensitivity and excellent morphological preservation compared to conventional processing techniques. Co-localization of in situ hybridization and immunohistochemistry probes with high morphological resolution was achieved using computerized image reconstruction. The latter may allow for the co-localization of multiple antigens and a specific DNA sequence at the same tissue level.
Use Tungsten Shadowing to Study Biological Macromolecules
Authors: Ryazantsev Sergey N 
Published: July 2020

Abstract
Shadowing is widely used for biological macromolecules and their complexes structure determination. It has been shown that tungsten shadowing produces fine granularity and good structural detail resolution. We have developed a working prototype of an electron beam evaporator (“electron gun“) based on the principle described by V. Vasiliev. The electron gun has characteristics that allow us to deposit high quality films of carbon or even pure tungsten. in addition we have constructed a prototype sample handling apparatus for freeze drying and shadowing. The prototype allows tilting of +/- 90° in 2° increments, rotation (if desired) at 6 rpm, controlled heating at a rate of 1-2° per min, and cooling using a liquid nitrogen trap attached to the device. The system is vacuumed by 480 1/sec maglev turbomolecular pump with scroll pump at the first stage. It produces oil-free vacuum in 2-5*10-7 torr range, which we believe, is sufficient for good quality shadowing.
EELS Studies of ZnO and ZnO:In Films Deposited By Spray Pyrolysis
Authors: Paraguay D. F , Miki-Yoshida M , Espinosa-Magaña F 
Published: July 2020

Abstract
Zinc oxide based coatings are of much interest in science and technology due to their interesting applications, such as in gas sensor devices, transparent electrodes, piezoelectric devices, varistor,surface acoustic-wave devices,etc. Thin films of ZnO also have some advantages over indium tin oxide (ITO) and tin oxide, which are usually used as transparent conductors, the former are chemically stable to a hydrogen plasma such as that used in the elaboration of solar cells. Many techniques have been employed to produce zinc oxide based coatings e.g. radio frequency magnetron, spray pyrolysis, sputtering, chemical vapor deposition, sol gel, pulsed laser deposition, etc. Among these techniques, the spray pyrolysis has proved to be a simple, reproducible, and inexpensive method, particularly useful for large area applications.
The main features of the spray pyrolytic system are fully described elsewhere. We have used a spray system attached onto mobile stage that provides a sweeping movement to the spray nozzle.
TEM Studies of Disorder-Order Transition in the Acid-Catalyzed Growth of Mesoscopic Silica Thin Films
Authors: Yao N , Ku A Y , Saville D A , Aksay I A 
Published: July 2020

Abstract
Mesoscopic silica is synthesized by using a self-assembling organic species to direct the structure of an inorganic matrix. It has attracted much interest because of its potential for use in a wide variety of catalysis, separations and nanotechnology applications. The commercial success of this material depends on the ability to simultaneously tailor the channel size and organization. A more complete understanding of the mechanism by which the material forms should lead to improved control over the structure. Small angle X-ray diffraction studies have shown that there is an “induction period” which precedes the observation of well-packed channels in films grown at the air-water interface. However, scattering data alone are unable to establish how the development of order might occur. Direct observation of the evolution is necessary to determine the mechanism by which well-packed, nanometer-sized channels form.
Continuous mesoporous silica thin films were grown at the air-water interface.
Microanalysis of AFM Tips Coated with Cerium Oxide
Authors: Gilliss Shelley R , Fairer Jeffrey K , Ravishankar N , Schwabel Mark G , Barry Carter C 
Published: July 2020

Abstract
Cerium oxide is widely used for chemomechanical polishing (CMP) of silicate glasses. Uses include finishing of optical elements and planarizing dielectrics in the semiconductor industry. This study is designed to investigate the fundamentals of the cerium oxide/silica CMP process by measuring the interaction force between silicate glasses and cerium oxide. Surface forces involved in the polishing of glass by a cerium oxide abrasive can be studied in a controlled manner by measuring sample-tip interactions between a glass substrate and a cerium oxide tip in an atomic force microscope (AFM). Commercially available AFM tips have been coated with thin, uniform films of cerium oxide. By using a square pyramid tip as a template for the shape of the cerium oxide film, challenges related to irregular or blunt tip shape can be overcome. However, complete characterization of structure, shape and chemical composition is required before useful information can be obtained using the AFM.
An Investigation of Al-Rich Alloys in the Al-Cr-Ru System
Authors: Compton DN , Cornish LA , Witcomb MJ 
Published: July 2020

Abstract
Many aerospace components that operate in aggressive environments make use of coating techniques for protection. One of the alloy systems used in these coatings is Al-Cr-Ru, with typical alloy compositions between 20-35 at.% Al and 20-35 at.% Ru. Alloys with a higher Al content may provide protection through an aluminium oxide (AI2O3) scale which is resistant to high-temperature oxidation and corrosion. However, Al-rich alloys in the Al-Cr-Ru system have not been thoroughly investigated. Previously, the phase boundaries of the binary phases, except AI9Cr4, into the ternary were established. The two ternary phases (Ternary 1 and Ternary 2) were identified, although their phase boundaries were unclear. Thus more alloys have been studied to enable the liquidus surface, the solid phase projection and the 600°C isothermal projection to be drawn.
As-cast alloys were examined metallographically in the scanning electron microscope. The phases present were confirmed by X-ray diffraction, and the compositions obtained by energy dispersive Xray spectroscopy.
SEM Characterization of Hydrogenated Nickel
Authors: Tavares SSM , Lafuente A , Miraglia S , Fruchart D , Lambert B , Pairis S 
Published: July 2020

Abstract
The insertion of hydrogen in metals promotes severe modifications of physical and mechanical properties. in the case of nickel, hydrogen induces intergranular cracking [1] and decrease of ferromagnetism [2]. Hydrogen occupies the octahedral interstices of the fee structure promoting cell expansion. Large amounts of the fcc (β hydride may be produced by high pressure hydrogenation [3] or electrolytic charging [4]. The H/Ni relation (x) in the P hydride range from 0.6 to 1.0, depending on the method and conditions of hydrogenation. The β hydride is known to be metaestable at room temperature and normal pressure [5].
In this work, a thin foil (0.02mm thick) of high purity nickel was hydrogenated by electrolytic charging in a 1N H2SO4 solution with 20 mA/cm2 by 24 hours. AS2O3 was used as catalyst in a concentration of 5xl0−5mol/l. The hydrogenated samples were analysed by X-ray diffraction and SEM immediately after and 4 hours after the charging (room temperature aging).