Materials Literature
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Brillouin scattering of laser light has been used to measure the frequency of hypersonic sound waves in the range of 1010 Hz in PMMA as a function of temperature through the glass-transition region. A discontinuity in the temperature coefficient of sound velocity is observed at the glass-transition temperature; this i…
The compressive deformation behaviour of iron-aluminium alloy single crystals containing 23·8, 28·0 and 30·0 at. % Al has been investigated in the temperature range from 77° to 683°K. The results of these experiments verify the unusual deformation behaviour first observed in polycrystals. Specifically, long-range orde…
Abstract Infrared spectroscopic studies have been made of mixed crystals of linear polyethylene and perdeuteropolyethylene. On the basis of normal vibration analyses by Tasumi and Krimm it had been shown that the study of crystal splittings of internal chain modes in such mixed crystals could provide information on th…
Crystal-field parameters of Yb3+, Eu3+, Tm3+, Sm3+, Dy3+, and Er3+ ions in various garnet lattices have been analyzed using a development of the superposition model proposed by Bradbury and Newman. This effects, in principle, the separation of the crystal-field contributions of the different coordinated O2− ions and d…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural studies of hexacoordinate silicon. Tris(o-phenylenedioxy) siliconateJohn J. Flynn and F. Peter BoerCite this: J. Am. Chem. Soc. 1969, 91, 21, 5756–5761Publication Date (Print):October 1, 1969Publication History Published online1 May 2002Published inissue 1 October…
A model is proposed in which transient temperature profiles in circular wafers in a row during cooling are analyzed. Various effects such as the number of wafers in a row, the position of the wafer in a row, the ratio of the wafer radius to the wafer spacing, multiple reflections, and the contribution of conduction ar…
Thermoelastic γ' Cu–14.2A1–4.3Ni (w/o) martensite has been studied using the techniques of electron microscopy and electron diffraction, in order to explain the morphology on a microscopic scale. A plane of ridge which is frequently observed in a typical “spear-like” martensite has been identified as (121) γ' twinning…
Abstract A novel polyimide forming reaction is reported. Pyromellitic dianhydride undergoes a condensation polymerization with diphenylmethane diisocyanate in solution or under melt‐fusion conditions to give polydiphenylmethanepyromellitimide (II) and carbon dioxide. Polymer II was characterized by inherent viscosity,…
Abstract The uncatalyzed polymerization of neat levoglucosan (1,6‐anhydro‐β‐ D ‐glucopyranose) was studied at 190–210°C under argon, and the course of the reaction was followed by analyzing samples at various reaction times; the residual levoglucosan was determined by GLC, and the optical rotation of the mixture was a…
The reactions of selenium and tellurium with lithium, sodium, potassium, and tetramethylammonium borohydrides have been examined, using the hydrogen evolution as a measurement of the replacement of hydrogen by the chalcogen on the borohydride anion. Of all the possible reactions, only the combination of sodium borohyd…
The decomposition in vacuum of a cured polyimide resin (Skybond 700) was studied in detail using simultaneous mass spectral and differential thermal analysis. These data were complemented with kinetic studies of the polymer and selected model imides. The mechanisms involved in the decomposition of Skybond 700 at moder…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCarboxylic carbonic anhydrides and related compoundsD. Stanley TarbellCite this: Acc. Chem. Res. 1969, 2, 10, 296–300Publication Date (Print):October 1, 1969Publication History Published online1 May 2002Published inissue 1 October 1969https://pubs.acs.org/doi/10.1021/ar50022…
Several peptides were isolated from the protein silk fibroin of Bombyx mori by means of ion-exchange chromatography of a chymotryptic digest. The sequences of three of the peptides, Gly-Ala-Gly-Tyr, Gly-Val-Gly-Tyr and Gly-Ala-Gly-Ala-Gly-Ala-Gly-Tyr, were known from previous chemical work, but the sequence of the fou…
Abstract The thermal degradation of polyphenylenes and poly(phenylene oxides) was studied under vacuum at temperatures between 350 and 620°C. The volatile and solid degradation products were analyzed by mass spectroscopy, infrared spectroscopy, and elemental analysis. Overall mechanisms for the thermal breakdown have…
Cobalt(II) complexes of the type [Co(terpy)X2] (I), [Co(terpy)2]X2,nH2O (II), and [Co(terpy)2]Y2,nH2O (III), where X = Cl-, Br-, I-, NCS-, and Y = ClO4-, [BPh4]-, have been prepared and characterized by magnetic, spectroscopic, and conductance measurements. The ?mono? complexes (I) are 5-coordinated and monomeric, non…
Abstract NaGaO 2 existiert in 2 Modifikationen. Die Tieftemperaturform [orthorhombischer β‐NaFeO 2 ‐Typ: a = 5,30 1 , b = 5,51 9 , c = 7,20 1 Å Z = 4] wurde an Einkristallen aufgeklärt: Raumgruppe C –P2 1 nb; alle Teilchen in 4(a), Parameter vgl. Tab. 1. KGaO 2 (Einkristalle) kristallisiert orthorhombisch [a = 5,51 5…
High-purity nickel bicrystals with controlled grain boundary misorientations have been grown from the melt using an electron beam floating-zone technique. These bicrystals have symmetrical tilt grain boundaries with 10° misorientation between {111} planes tilted about a 〈112〉 axis, and 10° twist about a {111} axis. Th…
The small-angle x-ray scattering (SAXS) pattern of polypropylene (PP) drawn at various temperatures (Td = 20°, 100°, and 135°C) was investigated in a range of very closely spaced draw ratio (λ) values through the neck region. In the zone before the neck starts (λ = 1.05–1.1) the uniform diffraction ring due to microsp…
Abstract Deferration by reduction of free Fe 2 O 3 with Na 2 S 2 O 4 in the presence of Na citrate and NaHCO 3 caused a change in valence state of 10 to 35 per cent of the total structural iron in micaceous vermiculites, soils, nontronite, and muscovite. An increase in Fe 2+ on deferration was accompanied by an equiva…
A rigorous electromagnetic theory of the diffraction of light by blazed lamellar gratings has been developed. It is applied to calculate the diffracted power distribution of four gratings (R1 − R4) whose grooves have the following depths and widths (b,l) in units of grating period a: (0.433, 0.750), (0.333, 0.667), (0…