Materials Literature
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Experimental data are analyzed to show that for some polymer relaxations observed in dynamic mechanical experiments, the activation enthalpy and entropy appear to follow a series of empirical relations. These relations, which also apply to inorganic solids, indicate that melting temperature, thermal volume expansion c…
Three-dimensional x-ray diffraction data have been collected from single crystals of nitrogen at 50°K. The observed general condition, l=2n for hh2h̄l reflections is in agreement with the previously assigned space group, P63/mmc, and there are two molecules in the unit cell. The data agree equally well with two nearly…
The polarized infrared spectra of highly oriented crystalline films of polyethylene glycol were measured in the region 3500–400 cm—1. Five parallel bands and eleven perpendicular bands due to the fundamental vibrations were observed in the region 1500–600 cm—1. From the analysis of these bands, the polyethylene glycol…
The distribution of electrons in a semiconductor at high electric field is governed by a Boltzmann equation which describes the effects of the field, the phonons, and the ionization processes on the electrons. This equation can be converted to an integral equation for the space and energy dependent collision density b…
Abstract Natural diamonds have been thinned sufficiently by oxidation at 750 °C in oxygen or at 1350 °C in carbon dioxide for examination by transmission electron microscopy. Type I and type II diamonds as classified by infra-red and ultra-violet absorption measurements have been investigated and a difference in the n…
Dissolution of Ge proceeds through the oxidation of Ge by iodine. The etching rate is several hundred µg/cm 2 hr with the activation energy being approximately 0.22 e V /molec. and it is in the order: {100}>{110}>{111}. The etchant develops three-, two- and four-fold symmetrical patterns, bounded by {111} planes…
The chemistry of potassium in soil is elusive, as many factors govern release of the element from insoluble materials and its subsequent availability to plants. Advances have come with a better understanding of the behaviour of clay minerals, the finest particles of which have a major role. Potassium status and its me…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCopper Chromite-catalyzed Conversion of Some Glycols to DioxenesR. K. Summerbell, Donald M. Jerina, and Robert J. GrulaCite this: J. Org. Chem. 1962, 27, 12, 4433–4436Publication Date (Print):December 1, 1962Publication History Published online1 May 2002Published inissue 1 D…
The published observations pertaining to the vapor pressure of uranium have been examined for consistencies. Since it was shown previously by Rauh and Thorn that oxygen suppresses the vapor pressure, the experiment by DeMaria, Burns, Drowart, and Inghram involving a mixture of uranium and aluminum oxide contained in a…
The relative change in the saturation flux, $\frac{\ensuremath{\Delta}{\ensuremath{\Phi}}_{s}}{{\ensuremath{\Phi}}_{s}}$, has been observed on Fe and Ni at room temperature in the range up to 11 000 kg/${\mathrm{cm}}^{2}$ in hydrostatic pressure. It decreases almost linearly as the pressure increases for both Fe and N…
Calcium diferrite has been prepared at 1220°C in air. The lattice constants at 25° C of calcium diferrite have been determined by X‐ray powder data and have been based on the hexagonal system. They are a = 5.992 ± 0.004 A and co = 31.121 ± 0.008 A. The coefficients of thermal expansion were evaluated by X‐ray methods…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTWeathering and Stabilization of PolyolefinsJ. A. MelchoreCite this: Ind. Eng. Chem. Prod. Res. Dev. 1962, 1, 4, 232–235Publication Date (Print):December 1, 1962Publication History Published online1 May 2002Published inissue 1 December 1962https://pubs.acs.org/doi/10.1021/i36…
The migration pattern in a seven-ply structure is predicted theoretically on the assumption that the centre filament moves to an outer layer only when it is slack. The frequency of migration is dependent on the twist, the twisting tension, the free length in the twisting zone, the tension resulting from an extension o…
Abstract Results of heating five lime‐alumina mixtures for 3–120 h. at temperatures from 1045° to 1405° are presented. The mixtures were prepared from mixtures of CaCO 3 (calcite) and α‐Al 2 O 3 and also from co‐precipitated hydroxide gels. Significant departures from equilibrium were noted. In general the gel mixture…
Thin films of zone-refined aluminium have been bombarded at 80°c with a flux of 1.6 × 1010 fission fragments cm−2 sec−1 for various times. Defects can be discerned after 30 sec when the films are viewed in the electron microscope and after longer timès they enlarge into dislocation loops. The larger loops lie near {11…
Calorimetric measurements by Rao and Giauque (1960) showed some unaccountable residual entropy in crystals of [formula] at low temperatures. We have investigated the crystal structure in search of an explanation of the disorder. The resulting structure offers no possibility of disordered rings of hydrogen bonds such a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAlkaloid Studies. XXXIX.1 The Occurrence of Dihydrocorynantheol and Aricine in Aspidosperma marcgravianum WoodsonB. Gilbert, L. D. Antonaccio, and Carl DjerassiCite this: J. Org. Chem. 1962, 27, 12, 4702–4704Publication Date (Print):December 1, 1962Publication History Publis…
Instances of contact dermatitis from free formaldehyde in textiles continue to be reported from abroad, especially from the Scandinavian countries.<sup>1-3</sup>In the United States, a single report of dermatitis due to formaldehyde in paper has appeared.<sup>4</sup>Various formaldehyde resins are widely used for impr…
The ferroelectric switching time of barium titanate single crystals has been measured at room temperature as a function of electric field and crystal thickness. The switching time was found to be independent of crystal thickness at high fields in disagreement with earlier work by Merz, who found the switching time pro…
The absorption spectra and dielectric constants of three of the four polymorphs of 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX) have been examined. The difference in absorption frequencies shows that these crystal forms are more distinctive than are most polymorphs. Likewise the distortion polarizations of HMX-…