Materials Literature
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HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire H…
Diffusion of nitrogen in plates obtained by direct nitridation of 99.995 weight per cent zirconium sheets at 1150°C was studied using the 15 N gas‐solid exchange technique. These specimens were characterized by chemical analyses, density, lattice parameter, and structural measurements. The diffusion anneals were perfo…
Abstract Single crystals of the α‐rhombohedral boron modification, prepared by chemical vapor deposition, were investigated by Raman scattering. Twelve quite strong peaks were observed in the Raman spectrum. The results are compared with group theoretical predictions and a lattice dynamical model, recently developed f…
Using a properly parameterized functional form of the momentum autocorrelation function, we have calculated, in a closed analytical form, the average diffusion coefficient D of nematic liquid crystals in terms of the molecular parameters such as intermolecular distances, coupling strength and molecular dimensions. Usi…
Abstract The thermal decomposition of ammonium molybdate, between 100–600°C was studied by ESR technique. At 250 °C all ammonium molybdate was decomposed into molybdenum trioxide. Samples taken at 250, 300, 350, 400 and 450 °C all gave ESR signals. Samples at other temperatures (higher and below of this temperature ra…
Abstract Our objective has been to demonstrate that DSC is a convenient and rapid technique for the study of elastomer vulcanization characteristics. Although we have been concerned only with NR and NR-BR blends, the observation of exothermicity in sulfur vulcanization is quite general. Similar observations on sulfur…
The regulation of dihydrodipicolinate synthase (EC 4.2.1.52) and aspartate kinase (EC 2.7.2.4) was studied in Bacillus subtilis 168. Starvation for lysine gave depression of one aspartate kinase isoenzyme but not of dihydrodipicolinate synthase. Strains resistant to growth inhibition by the lysine analogue thiosine ex…
A model is proposed for discussing deep defect levels in covalent solids, based on the representation of the one−electron energies of the crystal by the eigenvalue spectrum of a small periodic cluster of atoms. Calculations of this model by semiempirical MO−LCAO methods for a vacancy problem in hexagonal boron nitride…
The lactate dehydrogenase of Lactobacillus casei, like that of streptococci, requires fructose-1,6-diphosphate (FDP) for activity. The L. casei enzyme has a much more acidic pH optimum (pH 5.5) than the streptococcal lactate dehydrogenases. This is apparently due to a marked decrease in the affinity of the enzyme for…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEpimerization of 2,4,6,8-tetramethylnonane and 2,4,6,8,10-pentamethylundecane, low molecular weight model compounds of polypropyleneU. W. Suter, S. Pucci, and P. PinoCite this: J. Am. Chem. Soc. 1975, 97, 5, 1018–1023Publication Date (Print):March 1, 1975Publication History…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExcitons in one-dimensional tetracyanoplatinite saltsP. DayCite this: J. Am. Chem. Soc. 1975, 97, 6, 1588–1589Publication Date (Print):March 1, 1975Publication History Published online1 May 2002Published inissue 1 March 1975https://pubs.acs.org/doi/10.1021/ja00839a059https:/…
Abstract Glauconitic and glauco-conglomeratic phosphorite rocks are areally widespread on the South African continental margin. The glauconitic phosphorites ( nearly equal 18% P 2 O 5 ) have packstone or wackestone textures and are composed of sand-sized grains of glauconite, with lesser amounts of microfossils and te…
The light scattering properties of nematic liquid crystal thin−film waveguides are studied both theoretically and experimentally. A Green’s function analysis of the depolarized light scattering induced by thermal fluctuations in the average molecular alignment is presented and it is shown that the power distribution o…
Abstract The solutes are D‐(+)‐glucose, tris(hydroxymethyl)aminomethane, urea, 4‐hydroxypyridine, and three n‐amino acids. The complex permittivity of the solutions has been measured in dependence of the frequency between 0.3 GHz and 38 GHz at 25°C. By fitting an appropriate relaxation function to the measured frequen…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGrowth Kinetics of Polyethylene Single Crystals. I. Growth of (110) Faces of Crystals from Dilute Solutions in XyleneM. Cooper and R. St. J. ManleyCite this: Macromolecules 1975, 8, 2, 219–227Publication Date (Print):March 1, 1975Publication History Published online1 May 200…
The compression creep behavior of Y 2 O 3 ‐stabilized ZrO 2 (YSZ) was studied at temperatures to 2000 ° C. The function of Y 2 O 3 content and grain size was tested in specimens with various impurity concentrations and porosity distributions. For relatively fine‐grained specimens, creep rates increased with the 1.5 po…
The magnetic properties, the pressure dependence of the Curie temperature (T c ) and the initial compressibilities of the series of compounds LaCo 5x Ni 5-x were determined. The compounds with x>or=0.6 are ferromagnets whilst for the compounds with 0.2<x<0.6 the ferromagnetic order is not stable at all temperatures be…
A technique for the preparation of large monodomain phospholipid bilayer arrays is described. Evidence for the monodomain nature of the samples, obtained from optical birefringence, light scattering, and x-ray diffraction experiments, is presented.
We present experimental and theoretical investigations on the Freedericksz transition of a homeotropic nematic slab in rotating magnetic field. Two characteristic fields, and one critical frequency are necessary to describe the behaviour of the sample : — Ha(ω) separates synchronous and asynchronous rotations of the d…
Abstract Na2MoO4·2H2O is orthorhombic, with the space group of Pbca and with cell constants of a=8.463(3), b=10.552(3), and c=13.827(6) Å; U=1234.8 Å3; Z=8. The crystals are composed of alternate layers of MoO42− tetrahedra and water molecules. The layers are connected by interlinking sodium cations and hydrogen bonds…