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Compositional control of plane group symmetry in tourmalines : an experimental and computer simulated TEM, crystallographic image processing and Mossbauer spectroscopy study

Tourmalines with different compositions show different plane group symmetries in experimental high resolution transmission electron microscopy (HRTEM) when projected along the c-axis. Fe-poor elbaite shows p31m symmetry, while Fe-bearing elbaite shows p3m1 symmetry. Rubellite shows p6 symmetry, while Fe-Mg-Al-bearing tourmaline shows a `pseudo' p6 type of symmetry. Symmetries p3m1 and p6 are not c

Structural characterization of yttria (Y2O3) inclusions in YBa2Cu3O7−x films : Growth model and effect on critical current density

A higher critical current and enhanced pinning was obtained in c-axis-oriented YBa2Cu3O7−x (YBCO)films having a higher density of semicoherent yttria (Y2O3) inclusions. The films were grown by sputtering and the inclusion density depends on the fraction of N2O in the sputtering gas. The inclusions were studied by transmission electron microscopy, both in planar sections and in cross-sections. They

Microstructure of amorphous C:H and metal-containing C:H films deposited on steel substrates

Cross-sectional transmission electron microscopy (XTEM), including high-resolution microscopy (HREM), was employed to characterize the interface between different amorphous hydrogenated carbon (a-C:H) films and steel substrates. Additional analyses using Auger electron spectroscopy (AES) and X-ray diffraction (XRD) were also performed. Films were deposited both by high-energy (50 keV) nitrogen ion

Needles in a haystack: an intersectional analysis of the descriptive, constitutive and substantive representation of minoritised women

Using a data set of 1.1 million speeches drawn from UK House of Commons debates during 1997–2017 and a combination of automated and manual content analysis, this study addresses three interrelated questions. First, to what extent are minoritised women constitutively represented in parliamentary debates? Second, which MPs do so? Third, how do MPs’ race and gender affect how they represent minoritis

Reactive magnetron sputter deposition of CNx films on Si(001) substrates : film growth, microstructure and mechanical properties

There is currently considerable interest in producing new materials with extreme combinations of mechanical properties such as high hardnesses and moduli. One example of such a material is crystalline C3N4, which has been predicted to have a bulk modulus higher than that of diamond. In this paper we report on experiments carried out to synthesize CNx thin films. The films were grown in an unbalanc

The influence of thermal processing on structural and electrical properties of WxSi1−x/Si multilayers

Thermal stability of WxSi1−x/Si multilayers (MLs) with x varying from 1 to 0.11 is studied by TEM and LAXS. The structure of the prepared samples is amorphous. Doping of W sublayers with silicon affects the interdiffusion process as well as the crystallization in these sublayers. We investigated these two processes (which have a detrimental influence on e.g. X-ray mirror stability) by annealing ou

Transmission electron microscopy of InP Stranski‐Krastanow islands buried in GaInP

InP islands in a matrix of GaInP are investigated by transmission electron microscopy (TEM). The islands are uniform in size and shape, and are formed though self‐organized Stranski‐Krastanow growth. The introduction of a 4 ML intermediate GaP layer eliminates the bimodal distribution found in films where the InP was grown directly on the GaInP layer. The achieved island density is around 2 × 109

What Constitutes Substantive Representation, and Where Should We Evaluate It?

This short article introduces a novel framework for conceiving of the substantive representation of marginalized groups – in this case, racially minoritized women in the UK House of Commons. I outline a rubric of eight facets of substantive representation. These evaluate the degree to which claims that constitute a group are also substantively representative of that group. In doing so, I contribut

IMPROVED SIZE HOMOGENEITY OF INP-ON-GAINP STRANSKI-KRASTANOW ISLANDS BY GROWTH ON A THIN GAP INTERFACE LAYER

Coherent InP nano-sized islands, embedded into GaInP, have been grown by metal-organic vapour phase epitaxy using the Stranski-Krastanow growth mode. Photoluminescence, atomic force microscopy and transmission electron microscopy studies show that the insertion of a thin similar to 4 monolayer thick GaP layer affects the critical thickness of the subsequently deposited two-dimensional InP wetting Coherent InP nano-sized islands, embedded into GaInP, have been grown by metal-organic vapour phase epitaxy using the Stranski-Krastanow growth mode. Photoluminescence, atomic force microscopy and transmission electron microscopy studies show that the insertion of a thin ∼ 4 monolayer thick GaP layer affects the critical thickness of the subsequently deposited two-dimensional InP wetting layer, in

TRANSMISSION ELECTRON-MICROSCOPY INVESTIGATION OF THE MORPHOLOGY OF INP STRANSKI-KRASTANOW ISLANDS GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

We have used transmission electron microscopy to determine the morphology of InP Stranski-Krastanow islands in GaInP, grown by metalorganic chemical vapor deposition at 580 degrees C. We investigated both capped and uncapped islands. It was found that the fully developed islands have the principal shape of truncated pyramids with a hexagonal base both before and after overgrowth. The planes definiWe have used transmission electron microscopy to determine the morphology of InP Stranski–Krastanow islands in GaInP, grown by metalorganic chemical vapor deposition at 580 °C. We investigated both capped and uncapped islands. It was found that the fully developed islands have the principal shape of truncated pyramids with a hexagonal base both before and after overgrowth. The planes defining the

Microdomains, Solid Solutions and the "Defect Fluorite" to C-Type Sesquioxide Transition in CeO2-RO1.5 and ZrO2-RO1.5 Systems

Satellite dark field (SDF) imaging is used to show that there is a definite change in symmetry on moving across the two-phase region separating the so-called "defect fluorite" and C-type sesquioxide solid solution regions in (1 - x)CeO2 · xRO1.5 and (1 - x )ZrO2 · xRO1.5 systems. SDF images of the "defect fluorite" side of the two-phase region are characterized by a microdomain texture on the ∼100

In-situ grown dots of InP on GaAs and GaInP - A comparison

Shape, size and density of dots of InP on GaInP and GaAs surfaces, formed in-situ by the strain-induced phase transition from a two-dimensional (Frank-Van der Merwe) into a three-dimensional layer+islands (Stranski-Krastanow) morphology, are investigated. The observations support models which include the kinetics of island formation as important ingredients to explain the rather high size homogene

Kinetics of ethylene oxidation on plane Pt/SiO2 catalysts in the viscous pressure regime: Evidence of support activity

C2H4 oxidation on plane Pt/SiO2 model catalysts with various Pt loadings was studied at T = 373-473 K and in the pressure ranges 10-6-102 Torr C2H4 and 0.3-1500 Torr O2 (1 Torr = 133.3 Pa). Mass spectrometry combined with spatially resolved gas sampling enabled kinetic data to be collected far into the viscous pressure regime. Reaction orders and activation energies were similar to those of a macr

Growth and electronic properties of epitaxial TiN thin films on 3C-SiC(001) and 6H-SiC(0001) substrates by reactive magnetron sputtering

Epitaxial TiN films were grown on cubic (3C)-SiC(001) and hexagonal (6H)-SiC(0001) substrates by ultrahigh vacuum reactive magnetron sputtering from a Ti target in a mixed Ar and N2 discharge at a substrate temperature of 700°C. Cross-sectional transmission electron microscopy, including high-resolution imaging, showed orientational relationships TiN(001) ∥ 3C-SiC(001), and TiN[110] ∥ 3C-SiC[110],

Compositional information from amorphous Si-Ge multilayers using high-resolution electron microscopy imaging and direct digital recording

A simple method for extracting compositional information from high-resolution electron microscopy images of an amorphous two-element system using a slow-scan CCD camera has been developed. The method has been evaluated on amorphous Si/Ge multilayers. The characterisation of the multilayers provided information about thickness of the layers, maximum concentrations within the layers and elemental pr

Strain relaxation and thermal stability of the 3C-SiC(001)/Si(001) interface : A molecular dynamics study

Molecular dynamics (MD) and high-resolution electron microscopy (HREM) imaging are used to investigate the mechanism of strain relaxation of a model 3C-SiC(001)/Si(001) interface. It is found that the essential atomic mechanism governing this process is the formation of undulations in planes parallel and perpendicular to the interface. The net effect is the generation of misfit-accommodating dislo

A new silicon phosphide, Si12P5 : Formation conditions, structure, and properties

The formation conditions, structure, and properties of the recently discovered phosphide, Si12P5 (initially assigned Si7P3), have been studied using x-ray diffraction, high-resolution transmission electron microscopy, photospectrometry, and a four-point probe. The phosphide formed in amorphous Si-P alloy thin films with 30, 35 and 44 at. % P after annealing at 1000°C for 30 min. During annealing a

Digital HREM imaging of yttrium atoms in YB56 with YB66 structure

The arrangement of yttrium atoms in YB56with YB66structure was determined by high-resolution electron microscopy (HREM) using a slow-scan CCD camera. Digital HREM images recorded along the [100], [110], and [111] directions of the YB56crystals showed "averaged" yttrium atom positions in the boron clusters, which were also confirmed by image simulation. Digital HREM images recorded from thin region