Materials Literature
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The coordination and bond character of the cations in amorphous SiO 2 ‐Al 2 O 3 films prepared by rf sputtering were examined by studying chemical shifts in the SiK and AlK X‐ray emission spectra. The coordination number of Si ions in these films was always 4, regardless of composition, whereas the average coordinatio…
Grüneisen numbers, which relate the change in the phonon mode frequency to the applied strain, can be estimated if all the second-order and third-order elastic moduli are known. Expressions for Grüneisen numbers are normally found in the literature for cubic and trigonal crystals only. In the present work, for the fir…
Abstract The reduction of In2O3 by H2 or CO and the reoxidation of the reduced oxide by water, accompanying the formation of hydrogen, have been investigated at ≥673 K. The reduction of In2O3 and the decomposition of water have been expressed by the forward reaction and the backward reaction respectively of this equat…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNewton-Raphson approaches and generalizations in multiconfigurational self-consistent field calculationsDanny L. Yeager, Diane Lynch, Jeffrey Nichols, Poul Joergensen, and Jeppe OlsenCite this: J. Phys. Chem. 1982, 86, 12, 2140–2153Publication Date (Print):June 1, 1982Public…
Abstract Thin films of polypropylene were aged in air and in pure oxygen at pressures ranging from 0.051 to 4.24 MPa (7.4 to 614 psi) and temperatures from 60 to 90°C. Carbonyl formation resulting from polypropylene oxidation was monitored using infrared spectroscopy. The induction time for spectroseopically detectabl…
Causes of corrosion of metals and their alloys are reviewed. The corrosion mechanism is explained by electrochemical reaction theory. The causes and methods of controlling of both physiochemical corrosion and biological corrosion are presented. Factors which influence the rate of corrosion are also discussed.
Abstract Weatherability of several UV stabilized and unstabilized grades of LEXAN® polycarbonate (PC) was studied by exposure in a xenon arc lamp weather‐o‐meter. The tensile properties of thin (0.2 to 0.3 mm) compression molded and thick (3.4 mm) injection molded samples were investigated as a function of exposure ti…
The reflection spectra from a monodomain cholesteric liquid crystal are measured for obliquely incident light. The first order reflection region is found to be divided into three regions at a large angle of incidence. The central region shows high reflectivity irrespective of incident polarization and is attributed to…
Abstract Owing to their low cost phosphorus fire‐retardants find vast application in making fire‐retardant cellulosic compostions. They have been used both as a physical additive as well as part of the polymer structure. Acid forming phosphorus compounds are generally effective in cotton and other cellulosic. Acidic r…
Abstract The problem of dislocations emerging at free surfaces is considered. This complicated threedimensional elastic problem can be reduced to a superposition of two‐dimensional fields of infinite straight dislocations which are well defined. A plane fan‐shaped distribution of infinite straight dislocations is intr…
Line groups can be used in symmetry considerations of quasi-one-dimensional systems (as well as their spin subsystems), stereoregular polymers, chain-type crystals, etc. Each line group is expressed in the form of a weak-direct product of two of its subgroups. One of them is an axial point group, describing the symmet…
The corrosion behavior of pure iron in diluted (inhibiting) and moderately concentrated (aggressive) polyphosphate solutions has been re‐examined in the light of the results of surface analyses of iron samples by means of x‐ray photoeleetron spectroscopy. The passive film responsible for the anodic control of the corr…
The monocarbonyl complexes of (phthalocyaninato)iron(II), FePc(CO)L, where L = NJVdiethylacetamide, pyridine, piperidine, \nhexamethylphosphoramide, and triphenylphosphine oxide, have been prepared and characterized, as has the dicarbonyl \ncompound FePc(CO)2, which was isolated after exposing FePc i…
The primary lithium aluminosilicates in pegmatites are spodumene (a-LiAlSizOe) and petalite (LiAlSi4Or0). These minerals are frequently replaced by fine-grained assemblages of eucryptite (a-LiAlSiO+), albite, micas, and clay minerals as a result of subsolidus cation exchange reactions with residual pegmatitic fluids.…
Keywords BRIAN COLQUHOUN, CONSTRUCTIONAL STEEL RESEARCH AND DEVELO, PMENT ORGANISATION, WARWICK UNIVERSITY TENSION, FIELD, ACTION, COMPOSITE, PLATES, GIRDERS, TESTS, FAILURES, NEGATIVE, MOMENTS, STEEL, WEBS, SLENDER, STIFFENED, INTERACTION, PANELS, SHEAR, CONNECTIONS, SLABS, LIGHT, STEEL, TOP, FLANGES, ULTIMATE, STREN…
Abstract The theory of magnetic resonance Raman optical activity in metal porphyrins is developed. Irreducible tensor methods are used to calculate the transition polarizabilities (involving both symmetric and antisymmetric contributions) which are formulated in terms of a vibronic development of the Raman transition…
Measurements of dc electrical conductivity and emf of single crystal and polycrystalline α‐Al 2 O 3 doped, respectively, with 100 and 300 ppm yttrium show that yttrium, although isoelectronic with aluminum, is a donor. The electronic energy level of the donor is attributed to O 2‐ next to Y 3+ , its level being forced…
Abstract A polytype of InSe single crystals is determined to be of γ‐type by means of X‐ray Laue and diffractometer measurements. Polarized Raman scattering studies are carried out at room temperature and the spectra are analysed by using the normal modes of γ‐InSe. Two Raman lines of the A 1 mode (118, 228 cm −1 ) an…
Abstract Different montmorillonites (Otay, Chambers, Marnia, Camp Berteau, Moosburg, Greek White, Wyoming bentonite were deferrated with a dithionite/citrate solution; iron sulphide by-products were eliminated with an HCl washing and citrates with an H 2 O 2 oxidation. The smaller CEC after deferration could not be as…
Abstract The Upper Pliocene sediments near Lebrija in southern Spain contain commercial deposits of palygorskite and sepiolite. These sediments of continental origin consist chiefly of carbonate, marl, and clay resting on marine Pliocene quartzose sand. The lowest unit, the “Marly-Calcareous Bed,” consists of sepiolit…