Materials Literature
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Calculations are given for the frequency moments associated with the dipolar broadening of magnetic resonance lines in crystals having lattice points populated at random by identical paramagnetic ions or nuclei. It is found that for fractional magnetic population $f>0.1$ the line shape is approximately Gaussian wit…
Abstract Theories of Raman intensities are reviewed, and it is shown that no satisfactory theory exists which enables relative intensities to be predicted. A matrix method for calculating the derived invariants of the molecular polarizability in terms of polarizability functions characteristic of bonds and general coe…
The variation of electrical conductivity of MgO single crystals is measured as a function of temperature over the range from 300° to 1500°K. Heat pre-treatment is found necessary to stabilize the results at high temperatures. Assuming that the conductivity is electronic and intrinsic the energy gap between the full an…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInterconversion of Hexachlorocyclohexane IsomersR. R. Whetstone, F. C. Davis, and S. A. BallardCite this: J. Am. Chem. Soc. 1953, 75, 7, 1768–1769Publication Date (Print):April 1, 1953Publication History Published online1 May 2002Published inissue 1 April 1953https://doi.org…
Soil profiles examined in the parallel sand ridges between Ocean Beach and Woy Woy, N.S.W., show a progressive increase in podzolizatiun as one goes from the beach towards Woy Woy. There is reason to believe that the oldest ridges are about 4000 years old and it is thus possible to suggest a time scale for the leachin…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanism of Film Formation of Latex PaintW. A. Henson, D. A. Taber, and E. B. BradfordCite this: Ind. Eng. Chem. 1953, 45, 4, 735–739Publication Date (Print):April 1, 1953Publication History Published online1 May 2002Published inissue 1 April 1953https://pubs.acs.org/doi/10…
Infrared spectra are presented for three crystalline phases of methyl ammonium chloride which occur at different temperatures. The spectrum of the high temperature structure reveals apparently degenerate vibrational frequencies for the perpendicular bands indicating little or no distortion from a threefold symmetry ax…
The paper discusses the relation of the relaxation time τ of a dielectric to the measured decay time of polarization T and proposes a new expression for the internal field in a dielectric subjected to an alternating field. It is found for this expression that 1<T/τ<32 and that in most instances no seriou…
A brief outline is given of the spin-wave approximation to the near ground states of ferromagnetism and antiferromagnetism. Simple pictorial models of spin waves are introduced. These models clarify the striking difference between ferromagnetic spin waves, which obey the dispersion law ω ∝ k2, and antiferromagnetic sp…
Summary In his recent theory of work hardening, Mott assumes that face-centred cubic crystals usually contain, prior to deformation, a network of dislocations, as suggested first by Frank; and he computes the decrease in the modulus of rigidity due to the existence of such a network. His computation may be extended to…
Electron beam contamination has been studied in simple vacuum systems to determine how it originates and methods by which it may be prevented. It is concluded that the contamination is formed by the interaction of the electrons with organic molecules adsorbed on the bombarded surfaces, the molecules being replenished…
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In contrast to other inorganic solids, glasses may be permanently compacted by application of pressures of the order of 104 to 105 atmospheres. This effect was studied on two simple oxide glasses (SiO2 and B2O3) and several silicate glasses. The effect of compacting was studied by measuring the densities, dimensions,…
Abstract The Hall coefficient and resistivity of a range of polycrystalline graphites with different crystal sizes and a single crystal of Travancore graphite have been measured over a wide range of temperature. The number of free electrons has been found to be approximately 6x1018 per cm3 at room temperature; the var…
Abstract In liquids the molecular configuration is a function of temperature. If in a given substance super-cooling of the liquid is possible to such a low temperature—the ‘transformation temperature’ (Tg)—that the viscosity reaches about 1013 poises, the required changes in configuration become impossible and at all…
INTRODUCTION The following described materials have been unearthed partly during the construction of the Ch ngtu-Chungking Railway mainly in 1951 and partly during the clearing away the building foundation in Tatienwan, a suburb of Chungking.