Materials Literature
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The structure of aluminum chloride hexahydrate, A1C13.6H20, has been studied with X-ray and neutron diffraction techniques. Precise values for the dimensions of the hexagonal unit cell have been obtained: a= 11-827 + 0.006, c= 11.895 + 0.003/~. Single-crystal X-ray data have been used to confirm the space group, R3c,…
The transition region analysis of an abrupt heterojunction is extended to include the effects of mobile carriers‘ charge in the space charge regions. Deviations from the depletion model are obtained when the wide band-gap semiconductor is heavier-doped-This is due to a non-negligible potential drop across the narrow b…
Measurements have been made of the recoilless fraction and broadening of Mössbauer γ rays Rayleigh scattered from glycerol and sec-butyl benzene in the supercooled liquid, glassy and polycrystalline states, and from polycrystalline benzene. It is concluded that the vibration amplitude (possibly rotational in origin) i…
The bending behaviour of square plain-weave fabrics spun and woven from nineteen different fibres, each in a range of cover factors, has been studied. It is shown how this behaviour is determined by the mechanical properties of the fibre and the frictional and geometrical restraints within and between yams in the fabr…
The elastic Gibbs function at zero stress has been derived for ferroelectric crystals with point symmetry 4/mmm in the paraelectric phase, and the possible ferroelectric states have been examined. For the special case of bismuth titanate, recent optical data are used to derive the absolute orientation and the temperat…
Abstract Specimens of poly(methyl methacrylate) (PMMA) were compressed at nominally constant strain rates ranging from 10 −5 to 10 3 in./in./sec. at 0, 22, 50, and 115°C. A plot of stress at a small fixed strain (2%) and constant temperature versus logarithm of strain rate is sigmoidal in shape and, furthermore, time‐…
The crystallization of amorphous selenium is shown to occur by the formation of lamellas in which the molecular axis lies across the wide face and perpendicular to the growth direction. Below about 200°C the lamellas grow radially from a common nucleus branching noncrystallographically to produce a spherical crystalli…
The metal ions in CoFe2O4 when fired in air are probably randomly distributed over the cation sites of the spinel structure. The parameters (u is the coordinate of the O ions and l is the fraction of the tetrahedral sites occupied by Fe ions) of CoFe2O4 samples are: for a firing temp. of 1350 Deg and quenched in air,…
Index-of re fra ction ve rs us time iso th e rm s ha ve bee n esta bli shed for ge rmania glass. Us in g th e c rosso ve r te c hniqu e with air-q ue nc hed sampl es and app lyin g th e two relaxatio n tim e mod el pre viou s ly reported for borosilicate glass, it was found that th e width of th e spec tr~m of re laxa…
The crystal structures of ferroelectric and paraelectric (Glycine) 2 HNO 3 were determined by X-ray as well as by neutron diffraction methods at -150°C and at room temperature, respectively. One of the glycine molecules has the zwitter-ion configuration and another is mono-protonated. Thus the chemical formula should…
Abstract The angular dependence of scattering intensity of drawn polyethylene (PE) was investigated with a small‐angle Kratky camera. At constant drawing temperature the intensity drops drastically with increasing draw ratio; however, the position and the half‐width of the first maximum remain nearly unchanged. The dr…
The detection and identification of a surface compound formation on a steel surface was made using a backscatter Mössbauer effect technique. The compound was identified as β-FeOOH from Mössbauer effect parameters of iron oxide and oxy-hydroxide compounds. An estimate of the compound thickness is given based on a calcu…
A stochastic model has been developed that relates the stress-strain and the dilation-strain behavior of filled elastomers to the formation and growth of vacuoles which cause strain-induced volume dilatation in these materials. Both the cumulative and instantaneous frequencies of vacuole formation are simply derived f…
The phase boundaries of subliquidus immiscibility in the lithium, sodium, potassium, rubidium, and cesium borate systems were determined. Two‐phase structures were developed in thermal gradients and examined by direct‐transmission electron microscopy. No opalescence was observed. Microstructures were of the order of a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure of tris(ethylenediamine)chromium(III) pentacyanonickelate(II) sesquihydrate, [Cr(NH2CH2CH2NH2)3] [Ni(CN)5].1. 5H2OKenneth N. Raymond, P. W. R. Corfield, and James A. IbersCite this: Inorg. Chem. 1968, 7, 7, 1362–1372Publication Date (Print):July 1, 1968Publication…
Abstract The chemical equilibrium of a purified sample of hectorite was studied over a range of pH, silicic acid, and magnesium chloride concentrations. The quasi-equilibrium reached by about 6 weeks was reversible with respect to added magnesium ions but only partially so for added silicic acid. The free energy of fo…
Abstract The extent to which silicate minerals release Ca, Mg, Na, and K during the determination of exchangeable cations in soils by the ammonium‐acetate‐extraction procedure was evaluated. The method of exchangeable‐sodium evaluation used by the US Salinity Laboratory was employed for this study with the exception t…
Luminescence of complex ions is a general phenomenon; the number of such complexes in various electronic configurations found to show emission is increasing rapidly. For some it has been possible to assign the emission as phosphorescence or as fluorescence, for others the proper assignment is as yet not clear.
Abstract Four crystalline glyceroxides, that is, CaC 3 H 6 O 3 , Ca(C 3 H 7 O 3 ) 2 , Ca 3 (C 3 H 7 O 3 ) 6 · (C 3 H 8 O 3 ) 2 and Ca(C 3 H 7 O 3 ) 2 · (C 3 H 8 O 3 ) 4 were found in the system of calcium oxide‐glycerol in the temperature range from 10deg;C to 150°C. Phase equilibrium, solubilities, optical data, X‐ra…
The first order magnetic anisotropy constant K 1 of eight ferrites with inverse-type spinel structure and two ferrites with normal-type has been measured under hydrostatic pressure by the use of a torque method. The pressure dependence of K 1 , K 1 -1 ( d K 1 / d p ), in Li 0.5 Fe 2.5 O 4 is +4.1×10 -6 bar -1 , in NiF…