Materials Literature
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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…
A critical review is presented of all published data on phase transformation in zirconium and its alloys. Topics discussed include: The α → β transformation; factors affecting the stability of α and β zirconium; transformations in the β-phase including ω-phase formation, eutectoidal decomposition and strain induced tr…
Kirkendall void formation, which has hitherto prevented the use of the external diffusion technique for the manufacture of practical multifilamentary superconducting composites, can be suppressed by using solution anneals to eliminate sites for heterogeneous void nucleation.
The compositional dependence of the Urbach tail of Ge x Se 1- x compounds was measured in the range 0≤ x ≤0.4. The slope of the Urbach tail of Ge x Se 1- x compounds varies greatly with Ge content. It has a maximum at about x =0.3 and a minimum at the stoichiometric composition GeSe 2 . This specific dependence of the…
In Salmonella typhimurium and Escherichia coli, elongation factor Tu (EF-Tu) is methylated as shown by its incorporation of labeled methyl residues from [methyl-3H]methionine. Analysis of the nature of the methyl-containing residues by protein hydrolysis, followed by paper chromatography and high voltage electrophores…
The relationships h1 = h0 + Δhn and n = Δh−1(h1 − h0) [Gabe (1969). In Crystallographic Computing, edited by F. R. Ahmed. Copenhagen: Munksgaard], establishing the correspondence between the crystal indices h1 and the segment indices n of a given reflection, can be used to generate the reflections in the unique set, d…
The overall characteristics of the composites cured with a number of newly synthesized, tertiary aromatic amines compare favorably to those of resins polymerized with commonly used accelerators. Maximum compressive and tensile strength for the composites are obtained only over a narrow concentration range of accelerat…
The developing velocities of the positive and negative corona streamers on insulating plates have been measured by using the dust figure technique at low pressure in air. By applying nanosecond time pulses from 10- to 50-nsec duration to a needle point where the insulating plate is sandwiched in between the needle and…