Materials Literature
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Abstract 1 H and 2 H NMR spectra were recorded for the paramagnetic metallocenes Cp 2 M (M = V, Cr, Mn, Co, Ni). For Cp 2 V, Cp 2 Cr, Cp 2 Mn and Cp 2 Ni, a signal narrowing factor of 36–37 is observed on going from Cp 2 M‐ h 10 to Cp 2 M‐ d 10 , which is close to simple theoretical predictions. Additional quadrupolar…
Europium oxide has been investigated as a sintering aid and dopant for AIN. Pressureless sintering was carried out with 0 to 9 wt% Eu 2 O 3 additives, and dense sintered specimens were obtained using 1 to 4 wt% Eu 2 O 3 . With increasing Eu 2 O 3 content, two additional phases were observed in the X‐ray diffraction pa…
A vanadium oxide glass has been prepared by a rapid quenching technique, and the electrochemical lithium insertion into the glass has been investigated. The open‐circuit voltage (OCV) of the lithium cell with the glass gradually is decreased with increasing the stoichiometric parameter , while OCV of crystalline has t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTESR study of the dynamic molecular structure of a reentrant nematic liquid crystalAkbar Nayeem and Jack H. FreedCite this: J. Phys. Chem. 1989, 93, 17, 6539–6550Publication Date (Print):August 1, 1989Publication History Published online1 May 2002Published inissue 1 August 19…
Abstract This paper describes the development of process control schemes for the free radical initiated (reactive) degradation of polypropylene in an extruder (reactive extrusion). The objective of the work was to control the amount of degradation in order to produce polypropylene with a specified molecular weight. Th…
Direct current and alternating current electrical conductivity measurements are used to determine the activation energies for the formation of oxygen vacancies by breakup of bound defect complexes (0.32 eV) and their migration (0.84 eV) at low temperatures (<600°C) in Y 2 O 3 ‐fully‐stabilized ZrO 2 single crystals…
The adhesion of micro‐organisms to metal surfaces has been shown to be important in the corrosion process, but the cell surface structures participating in this adhesion have not previously been identified. Evidence is presented that a bacterial substance taking part in the initial adhesion of Pseudomonas fluorescens…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLiquid crystalline polyethers and copolyethers based on conformational isomerism. 3. The influence of thermal history on the phase transitions of the thermotropic polyethers and copolyethers based on 1-(4-hydroxyphenyl)-2-(2-methyl-4-hydroxyphenyl)ethane and flexible spacers…
This work deals with the changes in mechanical properties of yttrium oxide ceramics induced by nonstoichiometry. The maximum fracture toughness, K lc , is observed at the stoichiometric composition. For an oxygendeficient ceramic, a decrease of K lc is observed from 3.5 to 2.3 MPa.m 1/2 . On the other hand, the Vicker…
In an effort to clarify the effects of molybdenum, which greatly retards the kinetics of temper embrittlement of alloy steels, the incidence of intergranular fracture and the segregation of phosphorus and other elements to grain boundaries were studied in a series of Fe-Mo-P alloys by means of fracture experiments in…
Abstract The production of a polymer containing basic functional groups via the reactive processing of polyethylene was investigated. Grafting of dimethylamino ethyl methacrylate, DMAEMA, to linear low‐density polyethylene in the melt was carried out, and the effects of initiator type, feed composition, and reaction t…
Effects of n -type dopants Si and Se on band-gap energy ( E g ) and on sublattice ordering for Ga 0.5 In 0.5 P grown by metalorganic vapor phase epitaxy, under conditions in which E g shows anomalously low E g values if the doping is not carried out, were studied by means of photoluminescence and transmission electron…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoinduced electron transfer on a single .alpha.-helical polypeptide chainMasahiko Sisido, Ryo Tanaka, Yoshihito Inai, and Yukio ImanishiCite this: J. Am. Chem. Soc. 1989, 111, 17, 6790–6796Publication Date (Print):August 1, 1989Publication History Published online1 May 20…
Abstract High-resolution transmission electron microscopy (HRTEM) has shown regions of crystallites within noncrystalline matrices of three types of glass (volcanic glass, alkalic igneous glass, and synthetic, nuclear-waste-form glass) The volcanic glass fragments showed domains having 3-Å spacings. About 30% of the f…
Abstract Adsorption isotherms for water on homoionic (Ca 2+ , Li + , Na + , and K + ) exchanged forms of Crook County, Wyoming, montmorillonite (CMS Source Clay SWy-1) were measured between 25° and 70°C using a vacuum microbalance having automated control of water vapor pressure. From these adsorption data, integral e…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPuwainaphycin C, a cardioactive cyclic peptide from the blue-green alga Anabaena BQ-16-1. Use of two-dimensional carbon-13-carbon-13 and carbon-13-nitrogen-15 correlation spectroscopy in sequencing the amino acid unitsRichard E. Moore, Volker Bornemann, Walter P. Niemczura,…
The structures of the complexes of carboxypeptidase A with the amino acids D-phenylalanine and D-tyrosine are reported as determined by x-ray crystallographic methods to a resolution of 2.0 A. In each individual study one molecule of amino acids binds to the enzyme in the COOH-terminal hydrophobic pocket: the carboxyl…
The effect of gamma irradiation on the physicochemical properties of injectable human amnion collagen was investigated. Pepsin-extracted human amnion collagen was purified, reconstituted, and irradiated with varying doses of gamma irradiation (0.25 Mrads to 2.5 Mrads). Gamma irradiation had a significant impact on the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMetalloporphyrin .pi.-cation radicals: intrinsically ruffled or planar core conformations? Molecular structure mesitylporphinatocopper(II) hexachloroantimonateHungsun Song, Christopher A. Reed, and W. Robert ScheidtCite this: J. Am. Chem. Soc. 1989, 111, 17, 6865–6866Publica…
Synthesis and accumulation of poly(β-hydroxy-alkanoate) in Rhizobium leguminosarum, R. leguminosarum biovar. trifolii, Rhizobium ‘galega’, Rhizobium ‘hedysarum’ and R. meliloti were studied. Poly(β-hydroxybutyrate) is accumulated up to 55% of the cell dry weight. At 30–50% air saturation R. meliloti accumulates 50% of…