Materials Literature
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Electron beam transmission experiments have been performed, in the energy range 10 meV to 175 meV, with a magnetically collimated electron beam formed in a synchrotron radiation photoionization source using SuperACO, LURE. The apparatus has been calibrated with He and absolute backward scattering cross sections have b…
Porosity superlattices have been investigated by transmission electron microscopy, photoluminescence and reflectance spectroscopy. The superlattices were formed on p-type doped Si using two different techniques. Firstly, for homogeneously doped substrates we have periodically varied the formation current density and t…
The main purpose of this paper is to present a physical model of the positive discharge in long air gaps. A large number of previous experimental and theoretical studies led to the identification of the different successive phases of the spark development: formation and propagation of first corona streamers, inception…
Measurements of the space charge density across the width of a plane parallel sample of degassed crosslinked polyethene (XLPE) have been made recently. Repeated at intervals throughout a period of applied high voltage, these measurements provide data on the dynamics of charge injection and space charge development in…
Abstract Blends of polyphenylene sulfide (PPS) with a commercial, wholly aromatic, liquid crystalline polymer (LCP), Vectra‐B950, have been prepared by melt‐blending. Their rheological behavior has been studied in order to determine if the LCP displays a processing aid ability, and under what conditions it gives rise…
This work investigates the polarized charge-transfer (CT) spectra of the Jahn-Teller distorted CuCl 6 4- and CuBr 6 4- complexes formed in Cu 2+ -doped [N(CH 3 ) 4 ]CdCl 3 and [N(CH 3 ) 4 ]CdBr 3 crystals. The transition energies as well as the dominant polarization of the CT bands along the hexagonal c direction are…
Using real time spectroellipsometry (SE), we have studied the interfacial interactions that occur when i- and p-type hydrogenated amorphous silicon-carbon alloys (a-Si1−xCx:H) are deposited from hydride-containing plasmas onto transparent, conducting films of ZnO. The SE spectra collected during the nucleation of a-Si…
Abstract For rupture of rubber and plastics, three types are proposed: (a) elastic, (b) plastic, and (c) brittle. For (a) the rupture takes place at the ultimate elongation of chains between crosslinks. Strength f is proportional to the number of crosslinks and also the fraction of effective chains giving the optimum…
Abstract The structure, development, morphology, and dielectric relaxation have been investigated in poly(vinyl chloride)–thermoplastic elastomer (copolyester–ether) blends having different compositions. The changes in the intensities of dielectric relaxation peaks for the β and γ processes with respect to blend compo…
Abstract Gel permeation chromatography has been used to monitor the molecular weight changes that occur when polymers are degraded by photooxidation. Methods of sample preparation and procedures for conducting the chromatography measurements and for analyzing the results are discussed. Examples are given of applicatio…
Neutron powder diffraction studies as a function of temperature on MnPS 3 have revealed temperature-dependent features inconsistent with the previously quoted magnetic ordering. The features vanish at approximately 12 K, a temperature well above the accepted Neel temperature of 78 K. The features are consistent with a…
Abstract In a miscible displacement process, me condition of miscibility between oil and solvent can be achieved at pressures greater than a certain minimum. This minimum miscibility pressure (MMP) is one of the essential factors affecting oil displacement efficiency. The MMP of an oil-solvent system is often used as…
The chemical construction of organized architectures is an important aspect of innovative materials synthesis. Bicontinuous water-filled microemulsions can be used as preorganized systems for the fabrication of crystalline calcium phosphate materials with extended reticulated microstructures. These macroporous materia…
Specific protein-ligand interactions are critical for cellular function, and most proteins select their partners with sharp discrimination. However, the oligopeptide-binding protein of Salmonella typhimurium (OppA) binds peptides of two to five amino acid residues without regard to sequence. The crystal structure of O…
The potential for optical amplification at 1.3 µm is demonstrated in a dysprosium-doped gallium-lanthanum-sulphide based glass. Lifetimes of 59 µs are observed for the 6H9/2 - 6H15/2 transition for which the emission peaks at 1.32 µm. A radiative lifetime of 203 µs is calculated by a Judd-Ofelt analysis, indicating a…
The thermodynamic limit for the square-triangle random-tiling model is considered. The analytic solution of the Bethe-ansatz equations found recently by Widom (1993) is obtained. The analytic expression for entropy density as a function of the fraction of the plane occupied by triangles alpha t is derived for the case…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
An engineered fusion protein containing two tandem lactose permease molecules (permease dimer) exhibits high transport activity and is used to test the phenomenon of negative dominance. Introduction of the mutation Glu-325-->Cys into either the first or the second half of the dimer results in a 50% decrease in activit…
Supercooled liquids approaching the liquid-glass transition exhibit unusual properties associated with structural relaxation. The mode-coupling theory (MCT) of supercooled liquid dynamics shows that non-linear interactions among density fluctuation modes can produce effects resembling these observations. MCT produces…
Abstract The modification of the mechanical properties of polypyrrole (PPY) by electrochemical preparation of conductive composite film from pyrrole (PY) and three kinds of liquid crystalline copoly(ester‐amide)—PEA(H), PEA(C), PEA(O)—are presented. The electrical conductivity of the PEA(H)/PPY, PEA(C)/PPY, and PEA(O)…