Materials Literature
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Long-range pair potentials are presented for the fcc metals Ni, Au, Ag, Pt, Pd, Cu, and Al. Experimental data considered in deriving the potentials include the sublimination energies and stacking-fault energies as well as the lattice parameters, elastic constants, and vacancy-formation and -migration energies. A volum…
EXAFS has been measured at the Nb K-edge in the layered compounds NbSe 2 and at the Nb and Rb K-edges in the same crystal after intercalation with the alkali metal. Changes in bond length were measured to an accuracy of 0.004 AA. These changes were compared with changes in lattice parameters observed by X-ray diffract…
Arsenic selenide-telluride glasses have been investigated by X-ray absorption and photoelectron spectroscopy. The core electron energy shifts and chemical shifts in K-absorption edge measurements associated with the glass-crystal transitions of pure As 2 Se 3 and As 2 Te 3 have been studied. The effect of composition…
Synchrotron radiation sources, providing intense, tunable, polarized, and stable beams of ultraviolet and x-ray photons, are having a great impact on biology, physics, chemistry, materials science, and other areas of research. Synchrotron radiation has revolutionized solid-state photoelectron spectroscopy by enhancing…
In this paper we examine the mechanical and thermodynamic criteria which are necessary for equilibrium to exist in partial melts that are subject to hydrostatic stress. Existing theory satisfactorily demonstrates (1) that crystal‐liquid interfaces will have no sharp edges and will approach constant curvature and (2) t…
Degraded insulators of electronic components tend to ignite even when electrical energy supplied to them is less than 50 watts. This is also the case when the insulators are made of self extingushing polymeric materials. To evaluate the degradation of insulators, causes for the variation of data are investigated prima…
Synthetic crystals of tachyhydrite are trigonal, diffraction aspect R**, with hexagonal parameters a = 10.136 (1), c = 17.318 (2) Å, U = 1540.9 (3) Å3, Z = 3, Dc = 1.673 Mg m−3. Indexed powder data are given.
Abstract From the results of a structural analysis of cellulose crosslinked by a bifunctional reagent conclusions can be drawn merely on the distribution of crosslinks among individual hydroxyl groups. No information is available to what extent this distribution is caused either by different relative reactivities of t…
Temperature distribution on the surface of an energized polluted insulator has been measured using infra-red hermo thermovision techniques. Temporal variation of temperature has also been determined. Tests were carried out on a conventional ional cap and pin insulator unit. Results show that the maximum temperature of…
The cobalt (II) chelates of 1-(2-pyridylazo)-2-phenanthrol (PAPL) have been previously studied and the average magnetic susceptibility studied down to 80K.1 Two distinct complexes were isolated: (i) a green complex, Co(PAPL)2·2C2H5OH, which separates out from an alcoholic medium and (ii) a pink complex, Co(PAPL)2·4C2…
Abstract An equation is developed which describes the X‐ray scatter radiation from specimens of any thickness. This equation suggests that a specimen's mass absorption coefficient can be determined from its inelastically scattered X‐radiation not only when the specimen is ‘infinitely thick’ but also when it is of ‘int…
Abstract 2-Acyl-1,4-benzoquinones and 2-acyl-1,4-naphthoquinones underwent a novel type of regiospecific and stereospecific cyclodimerization by photolysis. The reaction was general, being not affected by any variation in the substituents and solvents. The structure of the dimers was elucidated as 4aα-acyl-10β-alkyl-5…
The phase relations and kinetics of ordering in fcc-type Cu 3 Au 1- x Pd x and Cu 3 Au 1- x Pt x (0≤ x ≤1) were studied. The L1 2 -phase, which is stable in the three terminal binary alloys, also exists in both these quasibinary systems over the whole composition range. The transition temperature from the L1 2 -phase…
Abstract A new perovskite La2⁄3(Mg1⁄2W1⁄2)O3 having an orthorhombic multiple-cell was synthesized. The lattice constants were a=7.8157(5) Å, b=7.8344(6) Å and c=2×7.9067(6) Å. The superstructure was found to be due to a NaCl-type ordering of B ions as well as an ordering of A-site vacancies.
Proton-induced absorption over the 280-700-nm region and growth of that coloring with increasing dosage of proton radiation were determined for three Schott glasses used as focusing elements in the International Ultraviolet Explorer. It was found that the absorption spectra for each glass can be fitted with three Gaus…
Rossmann and Argos [J. Mol. Biol. 109, 99–129 (1977)] observed that each of the two lobes which border the sugar binding cleft of yeast hexokinase contains a similar structural unit of five β-sheet strands and three α-helices. The strands are in the same order and two helices in each unit are on the outside of the mol…
(VSiW1 1O4 0)n− complexes exhibit two kinds of redox systems, those of vanadium (VV-VIV and VIV[sbnd]VIII) and those of the ligand. Electron transfers between the vanadium and the ligand are observed by change in the pH. Electronic spectra are discussed with regard to two types of electronic transitions, intervalence…
Threshold switching has been observed and studied in thin films of NbOx (x?2) in the sandwich configuration and in a single-crystal device having both a gap and sandwich configuration. The recovery curve has been determined by measuring the reswitching voltage after a specific zero-voltage interruption time. Data indi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleProtoporphyrin IX: some recent researchKevin M. SmithCite this: Acc. Chem. Res. 1979, 12, 10, 374–381Publication Date (Print):October 1, 1979Publication History Published online1 May 2002Published inissue 1 October 1979https://pubs.acs.org/doi/10.1021/ar50142a004https://doi.org/…
A mechanical model of the 2/2-twill weave is presented in order to investigate the tensile properties of this weave under biaxial extension. The theory predicts that the compressional deformations of the warp and the weft at their cross-over point produce a superior effect on the tensile properties of the weave, espec…