bluuebunny/crossref_metadata_2025 huggingface dataset:
Better Transparency and Conduction Via Alchemi: Site-Occupancy of Cations in Transparent Conducting Oxides (TCOs) Cd1+xIn2-2xsnxO4
Authors: Brewer LN , Dravid Vinayak P
Published: July 2020

Transparent conductive oxide materials (TCO) are currently under development for use as electrodes in devices such as photovoltaics and flat panel displays. As electrode area increases in large-area applications (e.g. photovoltaics), the resistivity of the TCO must decrease in order to maintain efficiency. The ideal next generation TCO will be a low cost material with a substantially higher conductivity than ITO obtained by improving mobility. Two promising TCO's are CdIn2O2 and Cd2SnO4 which both exhibit high conductivities (4300 S/cm and 8300 S/cm, respectively) and high mobilities (44 and 60 cm2/Vs, respectively).

A bulk investigation of the system CdIn2O4 - Cd2SnO4 reveals a large spinel solid solution, Cd1+xIn2.2xSnxO4 (0<x<0.75) at 1175°C exhibiting a sharp decrease in measured optical gap (from 3.0 to 2.8 eV) at x=0.2 and an increase in conductivity (from 2200 S/cm to 3500 S/cm) for reduced specimens between x=0.4 and x=0.60) with increasing x. It is suspected that the cation distribution (e.g. normal, random, or inverse) on the spinel lattice may be important in understanding these shifts in electrical and optical properties.
Variation of the ELNES Under Channeling Conditions
Authors: Köstlmeier S , Nufer S , Gemming T , Rühle M
Published: July 2020

The orientation dependence of the fine structure of the Al L1 and L2,3 electron energy loss (EELS) edges in (α-Al2O3 has been investigated by measurements with a dedicated scanning transmission electron microscope (VG HB501 STEM, 100 keV acceleration voltage). α-Al2O3 is an anisotropic solid with a complicated alternating stacking sequence of fee Al and hcp O planes along the [0001] direction [1]. This distingiushes the [0001] direction crystallographically, as the highest-order three-fold rotation axes (C3) of the trigonal crystal structure are parallel to [0001], whereas all other symmetry elements are of lower order. Group theory predicts, that more stringent symmetry selection rules apply when electronic transitions are excited by irradiation parallel to the low-index [0001] zone axis than by irradiation along any other arbitrary direction.

Yet, even for a low-energy EELS edge (θE = 0.4 mrad) both scattering parallel and perpendicular to the incident beam direction are likely.
Teoretical Tools for Practical ALCHEMI
Authors: Allen L J , Oxley M P
Published: July 2020

Precisely known atomic scattering factors are essential for accurate atom location by channelling enhanced microanalysis (ALCHEMI) based on inner-shell ionization.1 For ALCHEMI using energy dispersive x-ray analysis (EDX), first principles calculations of ionization cross sections, realistically modeling the “delocalization” of the ionization interaction, give excellent agreement with experiment.2 Such calculations are complex and computationally intensive. Hence, simple analytic forms are often assumed to describe the ionization potential. However such analytic forms require prior knowledge of the “delocalization” of the effective ionization interaction. Such an approach assumes that the precise shape of the ionization potential is not important but that at least the half width at half maximum (HWHM) should be accurately estimated, for example using estimates of the HWHM from root-mean-square impact parameters for ionization. However this is generally not a good approximation3 and we have provided more realistic estimates (Fig. 1).
ALCHEMI as holography
Authors: Spence JCH , Koch C
Published: July 2020

Two-dimensional Atom Location by Chanelling Enhanced Microanalysis ( Alchemi ) maps of characteristic Xray emission as function of the diffraction conditions of a 200kV electron beam hav been obtained from thin crystals by several workers. Reciprocity shows that these are equivalent to the diffraction patterns produced at infinity by 200kV point sources of electrons on atom sites, sue! as D in figure 1, for CsCl. Here ray SCD at left has been time-reversed at right. Using multislici superlattice simulations which launch a spherical wave from an atom site, we find that the resultinj Kikuchi pattern breaks up into separated blobs along the K-lines at small thickness, with one blol generated at infinity along each atomic string direction. Each blob (e.g. ID) is a Gabor in-lim hologram (e.g of atom C, formed by source S at right). Each source atom on equivalent sites (E, D produces identical holograms, whose intensities add.
Harecxs Measurements of Elemental Disordering
Authors: Zaluzec Nestor J , Smith Katherine L
Published: July 2020

It has been long known that orientation effects in crystalline materials can influence characteristic x-ray emission and microanalysis1-7. High Angular Resolution Electron Channeling X-ray Spectroscopy (HARECXS)6-7. a variation of ALCHEMI4-5, has been used at ANL for the last few years to investigate the effects of channeling on quantitative XEDS analysis of materials. More recently we have also been using HARECXS to carefully measure elemental disordering in a number of systems and have found that it can be used very successfully to elucidate the various stages of disorder.

Perovskite (nominally CaTiO3) is a host phase for actinides in various wasteforms for the immobilization of high level radioactive nuclear waste. Over geologic time, alpha decay damage of the actinides in perovskite will cause displacive effects that influence the dimensional and chemical stability of the wasteform. in the past, the progression of damage has been studied by monitoring changes in selected area electron diffraction (SAED) patterns with increasing dose (e.g. 11).
Study of Garnets by ALCHEMI
Authors: Lábár János L , Tόth Lajos , Dόdony István , Morgiel Jerzy
Published: July 2020

Garnets were one of the first materials in which an occupation of separate lattice sites by different atomic species was determined with an ALCHEMI technique proposed by Spence and Tafto in l982. The reason of so much interest in this material was twofold, i.e. first its known high sensitivity of X-ray generation depending on orientation especially in the axial orientation and second its complicated crystal structure allowing different atomic arrangements in the unit cell depending on its chemical composition. The dodecahedral (X), octahedral (Y) and tetrahedral (Z) sites between the relatively large oxygen atoms can be filled with a variety of small cations in accordance with the formula X3Y2Z3O12. Partial substitution of one cation with another is common in this structure. The results presented in the previous literature indicated that ALCHEMI can only separate the Y-sites from the sum of the other two (X+Z), while the latter has to remain unresolved.
Is Negative Staining Capable of High Resolution?
Authors: Massover William H
Published: July 2020

Everyone presently answers “no” to this question, since this methodology for specimen preparation and preservation commonly is believed to be inherently limited to 20-25Å (2.0-2.5nm) resolution. Achievement of resolution levels smaller than this figure have been published only rarely. This report presents experimental evidence from electron diffraction showing that negative staining can preserve periodic protein structure to the level of at least 4Å.

A suspension of bovine liver catalase crystals (orthorhombic: a= 69Å, b= 174Å, c= 206 Å [1]) is deposited on a hydrophilic carbon support and negatively stained using an on-grid protocol [2,3]. For low-dose electron diffraction with a JEOL 100CX transmission electron microscope (l00kV), the set-up for routine selected area diffraction is modified to keep the second condenser lens maximally overfocused; by a defocusing of the diffraction pattern, the grid can be surveyed and suitable thin single crystals centered in the diffraction aperture with only negligible irradiation.
Considerations for Multi-Phase and Low-Symmetry Com Analyses
Authors: Camus Patrick P , Rohde David B , Schwarzer Robert A
Published: July 2020

EBSD analyses are routine for understanding and quantifying the orientations of materials. Analyses of single-phase cubic materials are by far the most prevalent reported in the literature. However, the understanding of the orientations of multi-phase materials are just as important from a technological standpoint. The analysis of non-cubic and non-hep materials is also of interest to investigators. However, analyses of these materials provide some unique challenges for accurate and precise orientation and phase determination compared to cubic materials. The ORKID analysis system was designed from the beginning to address these materials and analysis concerns.

Single-phase materials, especially with cubic symmetry, do not require any special treatment for indexing of diffraction patterns. Because only one crystal system is under investigation, the algorithm for matching the measured bands and the expected bands can have some relaxation in error limits. Furthermore, d-spacing measurements of the bands are not strictly required because the bands angles are sufficiently unique.
Nucleation of Aln on 6h-Sic (0001) by Sublimation Technique
Authors: Liu B , Walker LR , Shi Y , Edgar JH
Published: July 2020

A study of the initial stage of AIN growth on SiC substrate by the sublimation re-condensation technique was undertaken to understand the origin of crystal defects in bulk AIN crystals. When SiC was used as a seed crystal the AIN crystals did not completely coalesce, and individual grains were observed. Such crystal growth features were determined by the initial nucleation of the crystals. in this study, the nucleation of AIN on 6H-SiC(0001) was investigated by Scanning Electronic Microscopy (SEM), S-4700 Hitachi, and Electron Backscattered Diffraction (EBSD), Thermo Noran Phase ID.

At high temperatures (>1800°C) in the presence of AIN, the surface of the SiC substrate first decomposed along remnant polishing scratches[l], ultimately leaving hexagonal hillocks; simultaneously, the AIN nucleated on these SiC hillocks. Surprisingly, the AIN nuclei appeared out of alignment with the underlying SiC hillocks. By measuring several points from the SEM image (figure 1), this misorientation is in the range of 15° to 30°.
Effect of oxygen deficiency on Charge Ordering in La0.5Ca0.5MnO3-δ
Authors: Tao J , Jiang N , Spence JCH
Published: July 2020

Elastically-filtered transmission electron diffraction patterns of La0.5Ca0.5MnO3-δ have been obtained between 105K to 288K using the Leo 912 Omega. On heating La0.5Ca0.5MnO3 undergoes a transition from antiferromagnetic insulator to ferromagnetic metal (TN ∼ 150K) and then to paramagnetic insulator (Tc ∼ 230K). The q modulation wave vector along the b-axis direction arises from charge ordering of Mn3+ and Mn4+, and orbital ordering of dz  22 orbitals associated with Jahn-Teller distortions in the Mn3+O6 octahedra at low temperature. Both the intensity and the position of superlattice peaks change as a function of temperature during heating. The large incommensurability we see between 105K to 260K differs from that seen previously and proposed model. Figure 1 a) shows the lattice constants a, b, c related to the simple perovskite lattice parameters ap (ap ∼ 3.9Å) by a≈b≈ap and c≈2ap, and indicates the octahedral coordination.
Low Angle Grain Boundary Dewetting in Sapphire
Authors: Hockey BJ , Kang M-K , Wiederhorn SM , Blendell JE
Published: July 2020

The structure and composition of low angle grain boundaries produced in sapphire by a liquid phase sintering process were investigated by conventional and high resolution transmission electron microscopy (CTEM and HRTEM, respectively). Considering the current emphasis on producing ceramics with textured microstructures for various applications, the question of grain boundary wetting vs. dewetting has become a relevant issue to determining the microstructure development and the properties of these liquid phase sintered materials. Accordingly, the present study was designed to cover a wide range of tilt misorientations, twist misorientations, and boundary orientations.

The boundaries were formed by the directed growth of two sapphire plates, both having nominal <0001>, , or surface orientations through an alumina tape-cast containing an anorthite composition glass phase. After an initial hot-pressing stage, followed by an anneal at 1600° C for 200 hours, the samples typically contained a single boundary delineated by isolated pockets of entrapped glass, Fig. 1.
High Resolution TEM and EDX Investigation of Metal Coated Nanoparticles
Authors: Jiao Jun , Tang Fangqiong
Published: July 2020

Nanoparticles are increasingly being heralded as the next-generation building blocks for modern materials design. Coating of semiconductor, metal, or metal oxide nanoparticles with a thin layer of a compatible material makes possible the control of interparticle and particle-matrix interactions, thereby further improving functional properties of devices and expanding the range of potential applications. The core-shell geometry has previously allowed for the enhancement of luminescence of semiconductor nanoparticles, charging of metal cores, chemical and colloidal stability, and optimization of magnetic properties of nanoparticles.

The work reported here uses new approaches to synthesize metal-coated nanoparticles characterized with high-resolution electron microscopy (HRTEM), micro-diffraction, and electron energy dispersive X-ray (EDX). Colloidal uniform composite nanoparticles of SiO2/TiO2 were synthesized using the sol-gel process. Fig. l-(a) shows a TEM micrograph of a group of particles coated with an outer layer.
Microindentation behavior of the shell of the conch Strombus gigas
Authors: Su X , Zhang D , Heuer AH
Published: July 2020

Microindentation using a hard indentor is a very useful tool to probe the local mechanical properties (plastic flow, fracture, toughness, creep, etc.) of hard solids. We have used a depth sensitive indentation (DSI) version of this technique to study the shell of the conch Strombus gigas.In particular, we prepared polished sections in which the third order lamellae, the basic building block of the structure, could be indented along the three orthogonal directions; the indentation behavior along these three directions is quite different. Besides the normal information such as the hardness H from some typical dimension (typically the diameter of a pyramid-shaped indentation produced by a so-called Vickers diamond indenter) after indenting with a given load, the DSI technique also provides much additional information available from the loading and unloading curves. As can be seen from Fig. 1, the loading and unloading curves for the three orientations are quite different, as is the depth of the residual impression.
Cryo-TEM Observation of 3-D Ordered Aggregates of 5-nm Gold Clusters in Solutions
Authors: Balmes O , Bovin J - O
Published: July 2020

The preparation of frozen amorphous nano-meter thin films of solutions containing particles, and imaging with cryo- TEM, opens for the first time the possibility to study cluster assembles interacting with liquids. The method is here used to show evidence for assembly of ordered 3-dimensional aggregates of ligand stabilized 5-nm gold clusters in a long chain alcohol solution. The use of the plunge-freezing method allows freezing of solutions at a cooling rate that does not allow re-organization of the clusters. The stability of the amorphous solid solutions under the electron beam make it possible to record several pictures of the same aggregate at different angles and clearly identify the super-structure.

The sample preparation uses a modified controlled-environment vitrification system built in glass. Solidification of the liquid phase was achieved by plunging the solution, suspended in the holes of a lacy carbon on a copper grid, into liquid ethane (-174 °C) or in some cases liquid nitrogen.
Characterization of Carbon Nanotubes Grown by Chemical Vapor Deposition
Authors: Cochrane J , Zhu S , Su C-H , Lehoczky S
Published: July 2020

Since the superior properties of multi-wall carbon nanotubes (MWCNT) could improve numerous devices such as electronics and sensors, many efforts have been made in investigating the growth mechanism of MWCNT to synthesize high quality MWCNT. Chemical vapor deposition (CVD) is widely used for MWCNT synthesis, and scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) are useful methods for analyzing the structure, morphology and composition of MWCNT.

Temperature and pressure are two important growth parameters for fabricating carbon nanotubes. in MWCNT growth by CVD, the plasma assisted method is normally used for low temperature growth. However, a high temperature environment is required for thermal CVD. A systematic study of temperature and pressure-dependence is very helpful to understanding MWCNT growth. Transition metal particles are commonly used as catalysts in carbon nanotube growth. It is also interesting to know the how temperature and pressure affect the interface of carbon species and catalyst particles.
Microstructural Characterization of Thin Films TiO2 Deposited Inside a Tubing by Spray Pyrolysis
Authors: Miki-Yoshida M , Paraguay D F , Antunez W
Published: July 2020

The traditional application of titanium dioxide was as a white pigment; later, it was discovered their photocatalytic properties as an anode for the photo-oxidation of water. Furthermore, titanium dioxide films are now widely used in catalysis and photocatalysis because of low cost and other advantageous properties. For example, they have been used for decomposition of organic contaminants in air and water. Moreover, recent studies have reported bactericidal and detoxification effects of TiO2 thin films. It has been shown that TiO2- coated materials possess deodorizing, antibacterial, and self-cleaning functions under weak ultraviolet light. Titanium dioxide films can be prepared by many deposition techniques. One of them is the spray pyrolysis (SP) technique which is a low cost, simple to manipulate, and applicable to large-scale areas (final). Photocatalytic TiO2-covered tubing can be used to decompose organic contaminants and/or to sterilize microbial cells in air or water flows, using solar panel reactors or indoor panels irradiated with UV radiation.
Bismuth Nanowires for Potential Applications in Nanoscale Electronics Technology
Authors: Cronin Stephen B , Lin Yu-Ming , Rabin Oded , Black Marcie R , Gai Pratibha L , Dresselhaus Gene , Dresselhaus Mildred
Published: July 2020

Nanowires have potential applications in future generations of nanoscale electronics. Our motivation of studying Bi nanowires is based on the unique properties of bulk Bi. These include very small effective masses, a long mean-free path and the low melting point (271°C). Calculations of the transport properties predict that the Bi nanowires have a very high thermoelectric efficiency. The effects of quantum confinement are pronounced in Bi because of its small effective masses. The resulting change in the band structure of bulk Bi is shown in Fig. 1. The broken curves depict the band structure in which the T-point valence band overlaps with the L-point conduction band by 38mev making bulk Bi a semimetal. Due to quantum effects, the band edges split into subbands shown by solid curves. As the wire diameter decreases, eventually the lowest conduction subband and the highest valence subband no longer overlap and the material becomes an indirect-gap semiconductor (at ∼50nm diameter).
Phase Retrieval from Two Defocused Images by the Transport-Ofintensity Equation Formalism with Fast Fourier Transform
Authors: Volkov VV , Zhu Y
Published: July 2020

The problem of phase retrieval from intensity measurements plays an important role in many fields of physical research, e.g. optics, electron and x-ray microscopy, crystallography, diffraction tomography and others. in practice the recorded images contain information only on the intensity distribution I(x,y) = ψ*ψ*= |A|2 of the imaging wave function ψ = A*exp(-iϕ) and the phase information (ϕ(x,y) is usually lost. in general, the phase problem can be solved either by special holographic/interferometric methods, or by noninterferometric approaches based on intensity measurements in far Fraunhofer zone or in the Fresnel zone at two adjacent planes orthogonal to the optical axis. The latter approach uses the transport-of-intensity equation (TIE) formalism, introduced originally by Teague [1] and developed later in [2]. Applications of TIE to nonmagnetic materials and magnetic inductance mapping were successfully made in [3,4]. However, this approach still needs further improvement both in mathematics and in practical solutions, since the result is very sensitive to many experimental parameters.
TEM Specimen Preparation Techniques and Analysis of Photo-Thermo-Refractive Glasses (PTRG)
Authors: Francois-Saint-Cyr H , Elshot K , Le Coustumer P , Bourrat X , Richardson K , Giannuzzi L , Glebov L , Glebova L , Stevie F
Published: July 2020

Due to their ability to undergo a refractive index change (Δn) induced by appropriate UV irradiation and thermal development, Photo-Thermo-Refractive (PTR) glasses are candidate materials for use in optical applications such as hologram recording, optical data storage, or spectral filters. Although this induced index modulation (Δn) has been characterized in terms of its optical ramifications, glass scientists are working to understand more clearly, the underlying mechanisms associated with the photo-induced crystallization process. For example, the phase, concentration and size of crystals responsible for the induced index change, the diffusion and growth process leading to the resultant optical behavior, and the precise role of the active components of PTR glasses, has yet to be completely elucidated. Numerous techniques have been employed to address these questions and this paper reports results of sample preparation and analysis of PTR glasses using Transmission Electron Microscopy (TEM).
In Situ Observation of Nanocrystal Formation Via Dehydroxylation
Authors: Sharma Renu , McKelvy M J , Bearat Hamdallah , Chizmeshya Andrew VG , Carpenter RW
Published: July 2020

Recently, a promising new route to prepare nano phase composites with fine transition metal particles (2 - 50nm) has been proposed via dehydroxylation and dehydration process. Thermal and mechanical dehydroxylation process has also been used to form ultra fine powders of NiO-Ni(OH). We have found a substantially increased carbonation rate at room temperature (RT) for partially dehydroxylated brucite (Mg(OH)2) single crystal fragments. BET measurements confirm the increase in the surface area of partially dehydroxylated (90%) single-crystal Mg(OH)2 fragments, which directly contributes to the increase in carbonation reactivity. As dehydroxylation proceeds rapidly in a TEM column, due to high vacuum and electron beam effects, the atomic level nature of the process has not been understood until recently.6 We have observed the development of nanocrystals during in situdehydroxylation of Mg(OH)2.

Experiments were performed using a PHILIPS-430 electron microscope operated at 300KV, fitted with a differentially pumped environmental-cell (E-cell) and a Gatan Imaging Filter (GIF).
Comparative Analysis of Integrins and Cadherins as Cell Adhesion Molecules in Ascidian Sperm-Egg Interactions
Authors: Lim J , Leary D , Koch R A
Published: July 2020

The earliest events in ascidian fertilization require sperm-egg recognition, sperm activation and penetration of the egg's protective barriers before sperm-egg fusion can occur. Species selective recognition is known to depend on recognition by sperm of egg N-acetylglucosamine sites. Binding to these sites triggers the defining event of ascidian sperm activation called mitochondrial translocation. in this process, the mitochondrion becomes anchored to follicles cells surrounding the egg and then rounds up, moves to the base of the head and translocates onto the tail. This actimmyosin-dependent process provides the force for penetration. Activation of myosin depends on a signaling pathway that leads to internal Ca2+ release and external Ca2+ entry.

In order for actimmyosin interactions to provide the force for penetration, the mitochondrion must be anchored to the outer surface of the egg complex. Presumably this anchor must also attach to actin filaments that serve as the track for the mitochondrial translocation process.
Microscopic Characterization of a Mutant Sperm Line of the Fern Ceratopteris Richardii
Authors: Davidson Kelly A , Hickok Leslie G , Renzaglia Karen S
Published: July 2020

Mature sperm cells of Ceratopteris richardiiare spiraled over three revolutions and contain a locomotory apparatus with approximately 70 flagella attached at the cell anterior (Fig. 1). Abundant organelles are dispersed along the inner surface of an elongated, coiled nucleus (Figs. 1, 3, 8). The cytoskeleton comprises a network of microfilaments that encases the nucleus (Fig. 6) and two distinct microtubule arrays: a microtubular ribbon (spline) and flagella with anchoring basal bodies (Fig. 3). This study uses light, fluorescence, transmission electron (TEM), and scanning electron microscopy (SEM) to characterize cell organization in a motility impaired mutant sperm line of Ceratopteris.Because motility mutations likely involve the cytoskeleton, emphasis was placed on observing microtubule and actin arrays in the mutant compared to wild-type spermatozoids. Protocols follow Hoffman and Vaughn for TEM and Schmitt and Renzaglia for SEM. Microfilament arrays in relation to the nucleus were examined by rhodamine-phalloidin and DAPI fluorescence.
Measurement of Eggshell Thickness Between two Species of Sceloporus Lizards Using Scanning Electron Microscopy
Authors: Parker S , Polcyn D , Thompson J
Published: July 2020

Thermal environment exerts a strong influence on lizard life histories by constraining seasonal activity time, fecundity, growth, and embryonic development. in cold climates, extending the duration of egg retention within the female's body permits embryos to develop more rapidly than would be possible at ambient nest temperatures. The duration of egg retention time in the oviduct is largely constrained by the ability of the growing embryo to uptake oxygen and release carbon dioxide. Parchment shelled eggs of most squamates (lizards, snakes, and amphisbaenians) while permeable to water and gases, also acts as a diffusive barrier to gas exchange. As a result, most taxa with extended egg retention exhibit a concomitant reduction in eggshell thickness.

To assess the influence of thermal environment on egg retention time, I sampled eggs from the lizards Sceloporus occidentalis and Sceloporus graciosus(Phrynosomatidae) from three populations at high, intermediate, and low elevation, in the San Gabriel Mountains of Southern California.
Prevention of Salt Damage to Monuments: Esem and Time-Lapse Studies
Authors: Doehne E , Selwitz C , Carson D , de Tagle A
Published: July 2020

Introduction: “In time, and with water, everything changes.” —Leonardo da Vinci The crystallization of soluble salts in porous building materials is a widespread weathering process that results in damage to important monuments and archaeological sites. Salt weathering by thenardite (sodium sulfate) and mirabilite (sodium sulfate decahydrate) is especially destructive, yet is still not fully understood. Halite (sodium chloride) in contrast, is one of the least damaging salts. Previous work has also demonstrated the importance of airflow in salt weathering. Here we present new data that help explain why sodium sulfate is so damaging and also show how crystallization modifiers and changes in airflow can reduce salt damage in laboratory experiments.

Damage Mechanism: The behavior of sodium sulfate was documented using saturated solutions and oolites from Monks Park limestone (a stone well known to be vulnerable to salt damage) as test samples. Damage was evaluated based on the degree of cracking of the oolite.
Microbial Colonization of Heating, Ventilating and Air Conditioning (HAVC) Systems and Indoor Air Quality
Authors: Simmons RB , Crow SA , Ahearn DG
Published: July 2020

The rapid rise of energy costs in the 1970's and early 1980's brought about a number of energy conservation measures which are still in use today. Changes made in heating, ventilating and air conditioning (HVAC) systems increased the recirculation of conditioned air within buildings, while leakage of air through the building shell was sharply reduced. Air movement in modern buildings is typically under the control of centrally operated HVAC systems which do not allow for local control of airflow in particular areas by the occupants. Problems with the quality of indoor air in the work environment have resulted from some of these measures and collectively many of these phenomena have been referred to as the Sick Building Syndrome (SBS). SBS is a complex of symptoms, including eye and mucous membrane irritation, headache, cough, dizziness, chest tightening, fatigue and general malaise, which occur more frequently than would normally be expected (greater than 20%) among the occupants of a building.
Microstructure of Climate-Forcing Aerosols: Aircraft Traverses from Clean to Polluted Conditions in the Indian Ocean
Authors: Anderson James R , Crozier Peter
Published: July 2020

The Indian Ocean Experiment (INDOEX) was conducted in Feb.-Mar. 1999 in a large area of the Indian Ocean, Bay of Bengal, and Arabian Sea to investigate climate forcing produced by pollutant aerosol particles being transported out of India, Pakistan, and Indochina during the Northeast (“Dry“) Monsoon2. Pollutant aerosols can be transported a thousand km or more by prevailing winds as far south as the Inter-tropical Convergence Zone (ITCZ), the convective band that separates Northern and Southern Hemisphere tropospheric air. We present here results from TEM examination of aerosol particles collected on INDOEX research flights of the NCAR C-130 aircraft.

The climate forcing properties of sulfate aerosols over the oceans have long been recognized2. Sulfate and other particles scatter incoming solar radiation, reducing the amount of light (and heat) incident on the ocean surface and thus causing a cooling effect which may locally counter some of the warming effect due to greenhouse gases.
In SEM a New Method for Nondestructive Internal Microtomography of Semiconductors and IC
Authors: Liang Zhuguan , Xia Ling , Li Yawen , Wang Jian , Zhou Kailin , Li Ping , Xu Xiaohua , Rau EI , Hu Wenguo
Published: July 2020

It is very important to study a new method of nondestructive internal microtomography of semiconductors and IC. in this paper, we report some research results that were obtained in resent years using nondestructive internal microtomography (NDIMT) to study semiconductor materials(SM) and microelectronic devices (MD) in SEM. Now we can apply this method to detect the microstructures and defects in the subsurface of SM. The conditions of microstructures and the defects being or not in the subsurface of SM used directly depend on the quality of MD. By attaching a special attachment that was devised based on the NDIMT to SEM we can perform nondestructive internal microtomographic visualization of the subsurface of SM the tested SM may be used latter to produce MD. in this way NDIMT may be used to select good quality SM which can then be used for research and production of MD. The product yield and reliabilities of MD can therefore be improved.
Characterization of Phase Transformation by Fe-SEM and Fe-TEM Analysis
Authors: Horny Paula , Drouin Dominique , Gauvin Raynald , Botton Gianluigi A
Published: July 2020

The formation of a silicon alloy has been achieved by electron beam irradiation of a nickel-silicon bilayer. This process, called SiDWEL1, has been developed by Quantiscript. The nickel-silicon bilayer is very thin and the electron beam operates at low energy and current. Silicide formation occurred around the interaction volume of the electrons within the material. This paper describes the nature of the structures produced and the origin of the difficulties encountered with the characterization. The necessity of further analysis with TEM based techniques is highlighted.

Figure 1 presents a cross-section of a typical sample. The growth of silicide grains is induced by the e-beam irradiation of the stack for few microseconds. Nucieation is initiated by the diffusion of silicon atoms in nickel grains, induced by the heating arising from the electron beam interaction with the solid. A new phase is revealed by FE-SEM observation, after wet etching of the nickel film, as shown in figures 2 and 3.
New Scanning Electron Microscope Sharpness Standard: NIST Reference Material 8091 (Rm 8091)
Authors: Postek M T , Vladar A E , Zhang N-F , Larrabee R
Published: July 2020

All scanning electron microscopes, whether they are in laboratory or on the production line, slowly lose performance as the instrument is used. This loss of performance is due to a whole array of contributing factors including misalignments, contamination and increases in source diameter. Identifying a loss in “sharpness” easily recognizes this performance decrease. Reference Material 8091 (RM 8091) is intended primarily for use in routinely checking the sharpness performance of scanning electron microscopes (Fig. 1). RM 8091 is designed to be used in conjunction with the SPECTEL SEM Monitor Program, the NIST Kurtosis program,3 or the University of Tennessee SMART program. RM 8091 is supplied as a small, approximately 2 mm x 2 mm diced semiconductor chip. This sample is capable of being mounted directly on to a wafer, wafer piece or specimen stub for insertion into a laboratory scanning electron microscope or wafer inspection scanning electron microscope.
Microcharacterization of Defects Induced in Fused Silica by High Power 3ω UV (355nm) Laser Pulses
Authors: Stevens-Kalceff Marion A , Wong Joe , Stesmans Andre
Published: July 2020

There are many technical challenges to be overcome before controlled fusion reactions can be achieved. The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is being developed to initiate fusion reactions using the world's most powerful laser. Essential components of the Facility are the ultra pure silica (SiO2) lenses that focus the powerful laser beams on to the target. Irradiation with a high power laser has been observed to damage the silica lenses, resulting in the formation of defects. The ensuing degradation of the lens performance necessitates its replacement. It is therefore critical to characterize the induced defects and understand the laser damage initiation and evolution, so that damage mitigation strategies can be developed.

Cathodoluminescence (CL) microscopy and spectroscopy enables high spatial resolution and high sensitivity detection of defects in poorly conducting materials. It is therefore an ideal microanalytical technique with which to study laser irradiation-induced defects.
Characterization of Aluminosilicate Formation on the Surface of a Crystalline Silicotitanate Ion Exchanger
Authors: Young J S , Su Y , Li L , Balmer M L
Published: July 2020

Millions of gallons of high-level radioactive waste are contained in underground tanks at U. S. Department of Energy sites such as Hanford and Savannah River. Most of the radioactivity is due to 137Cs and 90Sr, which must be extracted in order to concentrate the waste. An ion exchanger, crystalline silicotitanate IONSIV® IE911, is being considered for separation of Cs at the Savannah River Site (SRS). While the performance of this ion exchanger has been well characterized under normal operating conditions, Cs removal at slightly elevated temperatures, such as those that may occur in a process upset, is not clear. Our recent study indicates that during exposure to SRS simulant at 55°C and 80°C, an aluminosilicate coating formed on the exchanger surface. There was concern that the coating would affect its ion exchange properties. A LEO 982 field emission scanning electron microscope (FESEM) and an Oxford ISIS energy dispersive x-ray spectrometer (EDS) were used to characterize the coating.
Morphology of Poly Amide Nanocomposites Characterized by Transmission Electron Microscopy (TEM) and Electron Spectroscopic Imaging (ESI).
Authors: Heckmann W , Ramsteiner F , Mehler Ch
Published: July 2020

The introduction of organophilic layered silicates into a polyamide matrix significantly improves stiffness and strength [1,2]. Two methods are known to prepare such nanocomposites. For both methods cations such as sodium, potassium, magnesium or calcium, located in the interlayer galleries of the layered silicates must be exchanged by quaternary alkyl ammonium ions containing at least one alkyl chain and so rendering the originally hydrophilic into an organophilic silicate. in the insitu-method monomeric caprolactam is intercalated between the modified silicate interlayers and subsequently polycondensated to polyamide. By this method the silicates can be broken down into their nanoscale building blocks as can be shown by TEM and ESI (Fig. 1). Another more direct possibility to delaminate the silicates is melt mixing in an extruder. with both methods similar degrees of delamination can be achieved.

This paper presents some of our morphological results on polyamide containing organically modified montmorillonite.
Precipitation Upon Hot Strip Mill Conditions of a Ti-IF Steel
Authors: Regone W , 𝚓orge Júnior A M , Balancin O
Published: July 2020

Upon hot strip mill of titanium Interstitial Free (IF) steels, during cooling from austenite to ferrite region, the level of interstitial elements not removed by steelmaking process is dropped down by Ti that combines with N, C and S. Some authors [1-3] have reported that the traditional precipitation sequence TiN, TiS, Ti4C2S2 and TiC occurs with freestanding particles formed by nucleation and growth processes. Other authors [4] have indicated that the transformation from TiS to Ti4C2S2 may be considered as a hybrid of shear and diffusion, i.e., faulted Ti8S9 (9R) + 10[Ti] + 9[C] → 41/2Ti4C2S2 (or H for its hexagonal crystal structure). At low temperature (≤930°C), the stabilization process continues through epitaxial growth of carbides on H phase. to study the evolution of precipitation upon hot strip mill conditions, samples of a Ti - IF steel were subjected to double straining tests [5] by means of a computerized hot torsion machine, at 1000 °C and 920 °C, with strain rate of 1 s-1 and interpass times ranging from 0.5 to 100 s.
Challenges in Root Cause Analysis of Particle Defects
Authors: Uritsky Yuri , Conti Giuseppina , Wang Charles , Brundle CR
Published: July 2020

The analytical needs in semiconductor technology have grown under the increasing demands imposed by reduced critical dimensions, increased wafer size, and complexity. Optical visualization, localization and counting of particles and defects has been extended to morphological and chemical characterization owing to the shifting balance from quality control to root-cause defect analysis. This becomes increasingly important because, via knowledge of the particle defect material plus the process/ hardware features, it leads to a direct path for the particle culprit and a methodical defect reduction procedure.

We present here specific examples from Applied Materials development, particularly related to particles formed during poly Si etch and during two different cleaning procedures (a) NF3 rf process chamber clean and (b) pre-clean (before subsequent deposition) of SiON film via Ar+ sputtering. These cases include identification of Br-based particles after poly-gate etch, and attempts to classify a variety of Al-containing particles of differing origins caused by too aggressive cleaning.
Lattice defects in LiCoO2
Authors: Gabrisch H , Yazami R , Fultz B
Published: July 2020

Rechargeable Lithium ion batteries are widely used as portable power source in communication and computer technology, prospective uses include medical implantable devices and electric vehicles. The safety and cycle life of Li ion batteries is improved over that of batteries containing metallic lithium anodes because the insertion of Li between the crystal layers of both electrodes was proved to be safer than the electroplating of Li onto a metallic Lithium anode. in Li-ion batteries, the charge transport is governed by the oscillation of Li ions between anode and cathode. They are sometimes called “rocking-chair“ batteries. The most common materials for these batteries are lithiated carbons for anodes, and transition metal oxides (LixCoO2) as cathodes.

LixCoO2 has an ordered rhombohedral Rm structure consisting of alternating layers of Co-O-Li-O-Co. The capacity and energy density of the batteries is limited by the amount of Li that can be stored in the anode and cathode materials.
Asphaltene Aggregation Kinetics in Crude Oil Using Confocal Microscopy
Authors: Johnston Robert J , Mason Thomas G
Published: July 2020

Confocal laser scanning microscopy (CLSM) has been used to study asphaltene aggregation kinetics by employing the microscope's automated acquisition to generate time-lapsed projection maps of aggregating asphaltenes in the autofluorescent matrix of crude oil. Heavy crude oils contain asphaltene particles resulting in the production of optically observable micron-sized asphaltene aggregates. These aggregates form as a result of attractive interactions induced by mixing the heavy crude oil with a poor solvent. This technique has been employed to determine the volume fraction of aggregated asphaltenes, ϕagg, and the time evolution of this phenomenon. The measurements cover a range of various concentrations of asphaltene volume fractions of the heavy asphaltenic oil, ϕm, from ϕm =0.001 to ϕm =0.4.

At each ϕm,after the mixtures have been made, approximately 20 μl of the crude oil is placed in a 20 μm deep flat-well quartz cell and immediately placed on a microscope stage.
Using Electron Diffraction Technique to Solve Real World Problems
Authors: Li Z G
Published: July 2020

Electron diffraction can be a very useful technique in solving real world structure-related problems. However, electron diffraction is much less widely used in industry compared to x-ray diffraction for several reasons. So far, application of electron diffraction has been limited to large-sized companies either to characterize newly synthesized materials in a research division or to directly support business activities in an analytical laboratory. New materials produced on a commercial scale are more and more complex with micro-, even nano-meter sized structures. Development of these materials on a commercial scale, for example, high temperature superconducting compounds, fullerenes, and giant magneoresistance devices [1-7], has increased demand for electron diffraction techniques considerably. Here, I would like to review how electron microscopists in industry solve their real world problems using electron diffraction techniques [8].

Unit cell determination. Unit cell parameters and atom coordinates of a crystal can be routinely determined by single crystal x-ray technique if the crystal is large enough (about 0.1 mm in size).
Transmission Electron Microscopy Study of Planar Defects in Polycrystalline CdTe Thin Films
Authors: Yan Y , Jones KM , Al-Jassim MM
Published: July 2020

CdTe is a promising photovoltaic material due to its near optimum band gap and high absorption coefficient. Polycrystalline, thin-film CdTe/CdS solar cells have demonstrated an efficiency of 15.8%. High density of extended defects is often found in polycrystalline CdTe films grown by close-spaced sublimation (CSS). So far, most investigations of defects in CdTe have focused on epitaxially grown films, and the reported extended defects are mainly lamellar twins. However, epitaxially grown films generally have a different microstructure compared to CSS grown polycrystalline CdTe thin films. in this paper, we report our study of extended defects in CSSgrown polycrystalline CdTe thin films by high-resolution transmission electron microscopy (HRTEM). We found that the extended defects are mostly lamellar twins and stacking faults. The stacking faults always propagate across the grains, without ending at a partial dislocation inside the grains.
Growth and Characterization of Ge/Si (112) Islands
Authors: Floyd M , Smith David J , Zhang Y , Drucker J , Tari S , Brill G , Sivananthan S
Published: July 2020

The spontaneous formation of so-called self-assembled quantum dots (SAQDs) during heteroepitaxial growth has attracted much recent interest because of potential device applications. Much attention has been directed towards the Ge/Si(001) system, in particular to characterize the island shape and size distributions as a function of growth conditions, i.e., Ge coverage and substrate temperature. Due to the lattice mismatch, a layer-to-island transition occurs at coverages greater than about 3 monolayers, and thereafter small, coherent hut clusters and larger coherent and incoherent dome clusters are observed. Interdiffusion of Si into the Ge islands as a strain-relief mechanism also occurs. Strategies for achieving better control of island size, shape, composition and separation continue to be sought. in this paper, we report a preliminary investigation of island growth in the alternative Ge/Si(l12) system.

The Ge/Si(112) samples were grown by molecular beam epitaxy using a Riber 2300 system equipped with a Ge Knudsen effusion cell.
Time Series Analysis of Transmesothelial Invasion by Endometrial Stromal and Epithelial Cells Using Three-dimensional Confocal Microscopy
Authors: Witz CA , Cho S , Centonze VE , Montoya-Rodriguez IA , Schenken RS
Published: July 2020

Using human peritoneal explants, we have previously demonstrated that endometrial stromal cells (ESCs) and endometrial epithelial cells (EECs) attach to intact mesothelium. Attachment occurs within one hour and mesothelial invasion occurs within 18 hours (Figure 1). We have also demonstrated that, in vivo, the mesothelium overlies a continuous layer of collagen IV (Col IV).

More recently we have used CLSM, to study the mechanism and time course of ESC and EEC attachment and invasion through mesothelial monolayers. in these studies, CellTracker® dyes were used to label cells. Mesothelial cells were labeled with chloromethylbenzoylaminotetramethylrhodamine (CellTracker Orange). Mesothelial cells were then plated on human collagen IV coated, laser etched coverslips. Mesothelial cells were cultured to subconfluence. ESCs and EECs, labeled with chloromethylfluorscein diacetate (CellTracker Green) were plated on the mesothelial monolayers. Cultures were examined at 1, 6, 12 and 24 hours with simultaneous differential interference contrast and CLSM.
Segregation of Heterologous GPI-Anchored Proteins Into Separate Membrane Rafts
Authors: Ratnam M , Gunning W , Wang J
Published: July 2020

Specific lipid self-associations in the fluid bilayer, particularly involving sphingolipids and cholesterol, are believed to result in the formation of membrane microdomains or “rafts” that mediate recycling of proteins between the cell surface and intracellular compartments or function as platforms for signal transduction events. Such membrane microdomains may be recovered in a low-density fraction that is insoluble in Triton X-100 at 4°C and referred to as detergent-insoluble, glycolipid-enriched complexes (DIGs). Membrane microdomains that constitute cell surface invaginations called caveolae can also be recovered in the form of DIGs. Caveolae are typically associated with a protein called caveolin, which coats their cytoplasmic surface.

Various glycosyl-phosphatidylinositol (GPI)-anchored proteins such as the folate receptor (FR) are believed to be associated with membrane rafts and to constitutively internalize and recycle to the cell surface although FR is the only known GPI-anchored protein with a transport function, i.e.,