Materials Literature
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Copper chromite, CuCr~O 4, is a tetragonally distorted normal spinel with a c/a ratio, as referred to a face-centered unit cell, of about 0.91. A structure which is physically reasonable, belonging to the space group D~-I42d, is based on an environment for the copper ions which is distorted from a tetr~hedron toward a…
Abstract A theoretical calculation of the energy levels, and hence absorption spectrum, of an isolated vacancy in an otherwise perfect diamond lattice has been made. The concept of a defect molecule is introduced. This enables familiar molecular orbital theory to be applied in calculating the electronic structure of t…
Abstract The bulk chemical properties of an impregnated chromia‐alumina catalyst with respect to several gases, CO, CO 2 , C 3 H 6 , were determined as a function of the degree of oxidation of the surface of the catalyst. The importance of the results lies in the demonstration that a simple method described herein can…
Abstract CaSi 2 wurde in geschmolzenem AlBr 3 bei Temperaturen zwischen 100°C und 200°C mit HBr behandelt. Es wurden hierbei bei den niedrigeren Temperaturen (etwa 100 bis 150°C) lepidoide Polysilane sehr niedriger Oxydationsstufe erhalten. Sie bestehen aus hexagonalen Si‐Doppelschichten. Die vierten Valenzen der Si‐A…
Room-temperature measurements on the variation of resistivity of pure InSb with hydrostatic and uniaxial stress were made to determine the piezoresistive and elastoresistive coefficients of pure InSb. The results are consistent with a spherical conduction-band model.
Abstract Extension of the kinetics of the catalytic oxidation of nitric oxide on activated carbon and silica gel confirms the rate‐controlling step postulated by previous workers. The effect of variables including water vapor on the reaction rate is expressed by an equation containing the constants a , b , c , and w ,…
Abstract The apparent vapor pressure of solid germanium dioxide, or the dissociation pressure for the reaction GeO2(c) = GeO(g)+1/2 O2(g), was measured over the temperature range 1,040 – 1,100°C by the Knudsen’s effusion method; the results are expressed by equation (4). From the free energy equation, the heat of reac…
Two batches of Merino wool, closely matched in fiber diameter and length, but dif fering in their crimp content. have been processed into worsted yarn on the French sys tem and converted into fabric. The changes in the properties of the fibers through processing have been followed. and the properties of intermediate a…
Abstract Si 3 N 4 wird erhalten durch Reaktion von elementarem Silicum mit Stickstoff oder Ammoniak, bzw. durch thermische Zersetzung von Si(NH) 2 bei 1350°C. Es existieren zwei polymorphe Modifikationen, α‐Si 3 N 4 und β‐Si 3 N 4 . Reines α‐Si 3 N 4 entsteht nur aus Si(NH) 2 , alle anderen Präparate sind Mischungen d…
The "vertical" divergence of the beam in a counter diffractometer causes a broadening, and a shift of centre of gravity, of diffraction lines. The effects do not disappear as 2 theta tends to 180°, and hence present extrapolation methods fail to remove the errors introduced. Experimental results are quoted that are no…
Research Article| September 01 1957 Preparation and characterization of the isomaltodextrins J. R. Turvey; J. R. Turvey 1Department of Chemistry, University College of North Wales, Bangor, Caernarvonshire Search for other works by this author on: This Site PubMed Google Scholar W. J. Whelan W. J. Whelan 1Department of…
The infrared spectra of solid Hg(CN)2 and the mono- and di-substituted C13 and N15 species have been observed. The polarized spectrum of a single crystal of the normal species was also observed. The seven fundamental vibrations of the linear, symmetric Hg(CN)2 molecule have been assigned at 2192, 415, 2193.5, 442, 276…
The chain‐length distributions in solutions of sodium phosphate glasses were reinvestigated using improved paper chromatographic techniques. The range of compositions was extended to glasses of higher Na/P ratios by using a through‐flame technique for their preparation. The distributions obtained confirmed the earlier…
X-ray studies showed a wide variation in lattice parameters of synthetic albites crystallized under varying conditions of temperature, time, and pressure. The data indicate that an infinite number of stable intermediate forms can exist between high- and low-temperature albite, and support the conclusion that the latti…
The isotherm corresponding to monolayer adsorption and the equation of state of a monolayer at a liquid interface are derived. As previously, we replace the number of segments per chain actually deposited, by an average value, which is proportional to t½ (t total number of segments) and depends on chain flexibility. T…
Abstract The physical properties of vulcanized 1,4 polybutadienes, prepared by heterogeneous catalysis and ranging from 95 per cent cis to nearly 100 per cent trans configuration, were investigated in gum and tread formulations. Comparisons were made at equal effective (physical) degree of crosslinking for both gum- a…
Summary From molecular distillation data, and information obtained by hydrogenation in dilute solution, extents of reaction have been calculated for the polymerization of linseed, safflower, tung, and oiticica oils. The hydrogenation data indicate that more than one double bond per molecule can be consumed during poly…
Abstract The losses of bacteriostats from rubber-closed multidose containers of injections are confirmed, and the mechanism of these losses by absorption, diffusion and volatilisation is discussed. The present B.P. methods of pretreating rubber closures are inadequate, and methods for their more satisfactory equilibra…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Gas Phase Constitution of Boric OxideMilton D. ScheerCite this: J. Phys. Chem. 1957, 61, 9, 1184–1188Publication Date (Print):September 1, 1957Publication History Published online1 May 2002Published inissue 1 September 1957https://pubs.acs.org/doi/10.1021/j150555a013http…
Summary A nephelinite from the extinct volcano Mt. Shaberu, North Kivu, Belgian Congo, contains two new minerals: Götzenite is triclinic with a 10·93, b 7·32, c 5·74 Å, α 90°, β 100°, γ 120°; the unit-cell contents approximate to (Ca,Na,Al) 7 (Si,Ti) 5 O 15 F 3·5 , and the optical constants are α 1·660, β 1·662, γ 1·6…