Materials Literature
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The spectrum of the luminescence in silica core optical fibers under x-ray excitation has been observed to consist of two distinct emission bands at 450 and 650 nm. The contrasting dose-dependent behaviors of the two bands show that they are associated with different luminescent centers in the glass matrix. The applic…
The permeation time-lag method have been used to determine the permeabilities, diffusion coefficients and solubilities of hydrogen and deuterium in type 304 stainless steel of three kinds of surface treated specimens; with oxide film, reduced by H2 gas and Pd coated. For the specimen with a thin oxide film the permeab…
Abstract As shown by scanning and transmission electron microscopy, halloysite in three rhyolitic tephras occurs as squat and elongate ellipsoids. Both morphologies are presumed to result from a similar lattice building mechanism. The squat ellipsoids form from allophane; the elongate ellipsoids form from feldspars. T…
Abstract Because of discrepancies in the literature a redetermination of the structure of talc Mg 3 [(OH) 2 Si 4 O 10 ] is reported. Space group of talc is P [unk] with lattice parameters a 0 = 529.1(3) pm, b 0 = 946.0(5) pm, c 0 = 529.0(3)pm, α = 98.68(5)°, β = 119.90(5)° and γ = 85.27(5)°, Z = 2. Transformation by a…
In heme-deficient reticulocytes and their lysates, a heme-regulated inhibitor of protein synthesis is activated; this inhibitor is a cyclic AMP-independent protein kinase that specifically phosphorylates the alpha subunit of the eukaryotic initiation factor 2 (eIF-2 alpha). Heme regulates this kinase by inhibiting its…
Microstructural characterization of conventionally sintered, hot‐pressed, reaction‐sintered, and chemically vapor‐deposited polycrystalline SiC shows that the initial stages of the β→α transformation in the first three materials are similar, the process being dominated by the elimination of high‐energy β→α interfaces.…
Semianalytical formulas are developed to predict scabbing and perforation thicknesses for reinforced concrete panels subjected to impacts by solid steel missiles. The scabbing thickness is defined as the thickness that is just enough to prevent the peeling off of the back face of the panel opposite to the face of impa…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and relation between magnetism and structure of a trinuclear copper(II) hydroxo complex [Cu3OHL3(ClO4)]ClO4 and a hexanuclear copper(II) oxo complex [Cu3OL'3(ClO4)]2(LH=3-(phenylimino)butanone 2-oxime, L'H=1,2-diphenyl-2-(methylimino)ethanone 1-oxime)Ray J. Butcher…
The final stages of the β→α polymorphic phase transformation in conventionally sintered and hot‐pressed SiC were studied by optical and transmission electron microscopy. The interface between the α and β regions of partially transformed grains invariably contains thin α lamellae adjacent and parallel to coherent β twi…
Compressive strength of SiC and Al 2 O 3 is determined over a wide range in loading rate. The results are interpreted in terms of the tensile growth of axial microcracks, controlled by two distinct mechanisms. The first is a material‐dependent, thermally activated process operative at strain rates 10 2 s; the other is…
The influence of potential and nominal sea water velocity upon the nature of calcareous deposits formed upon a cathodic steel surface has been investigated. Specific attention was focused upon change with exposure time of the current density to maintain a prescribed cathodic potential and upon thickness of the calcare…
Abstract Measurements on the thermal expansivity α ∥ and α ⟂ (along and normal to the draw direction, respectively) have been carried out for a series of oriented polymers with widely different crystallinities (0.36–0.81) and draw ratios (1–20) and over large temperature ranges covering the major amorphous transitions…
Copolyesters (CPEs) prepared by the transesterification reaction between aromatic and aliphatic polyesters were hydrolyzed by Rhizopus delemar lipase. The susceptibility of CPEs to hydrolysis by this lipase dropped off rapidly during the initial stage of the transesterification reaction and increased gradually as the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew approach to bonding in transition-metal clusters and related compoundsA. J. StoneCite this: Inorg. Chem. 1981, 20, 2, 563–571Publication Date (Print):February 1, 1981Publication History Published online1 May 2002Published inissue 1 February 1981https://pubs.acs.org/doi/1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCharge-transfer diffusion rates and activity relationships during oxidation and reduction of plasma-polymerized vinylferrocene filmsP. Daum and Royce W. MurrayCite this: J. Phys. Chem. 1981, 85, 4, 389–396Publication Date (Print):February 1, 1981Publication History Published…
Abstract Group theoretic methods are used to list by c repeat and space group polytypes of mica with layer-number N ≤ 24, kaolinite and cronstedtite with N ≤ 12, and chlorite with N ≤ 6. General formulas are given to count the total number of polytypes of these minerals with any layer-number N .
Abstract Group-theoretic methods arising from Pólya's theory of counting are used to enumerate close-packings and polytypes of ZnS, CdI 2 , and SiC having layer-number N ≤ 50. The close-packings are further classified by space group. The barium ferrites of the form M N Y S with N = 2,4,6,8, lO and S ≤ 20 are enumerate…
It had been shown previously that the heat-stable polypeptide of the ATP-dependent proteolytic system of reticulocytes, designated APF-1, forms covalent conjugates with protein substrates in an ATP-requiring process. We now describe an enzyme that carries out the activation by ATP of the polypeptide with pyrophosphate…
A broad review of the physics of point defects, i.e. electrically active and neutral impurities and impurity complexes is given. Basic material science which is crucial for understanding the physics is summarized in an introductory section. It is followed by the detailed description of the novel measurement techniques…
The corrosion rate of copper in laboratory tests is shown to be a sensitive function of relative humidity, sulfur dioxide, hydrogen sulfide, ozone, hydrogen chloride, and chlorine concentrations. Observed indoor corrosion rates obey log normal statistics over the field population of this study. Also, the observed indo…