Materials Literature
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The Dzialoshinsky-Moriya (DM) antisymmetric exchange interaction between superexchange-coupled ions in antiferromagnetic salts is shown to contribute to the exchanged-narrowed electron-paramagnetic-resonance (EPR) linewidth in the paramagnetic state. The contribution of antisymmetric exchange to the second and fourth…
Transient nuclear spin-lattice relaxation measurements have been made in indium metal and the InCd, InTl, InSn, and InPb dilute alloy systems, using the ${\mathrm{In}}^{115}$ nuclear-quadrupole-resonance (NQR) spectrum. The theory of spin-lattice relaxation in NQR is described for both magnetic and quadrupolar contrib…
Previous work on the rapid formation of a hydride of SmCo5 at room temperature is confirmed. It is shown that the rate of release of hydrogen is related to the rate of transformation of the hydride to the unhydrided compound, rather than by bulk diffusion of hydrogen. The rate-controlling step is probably the allotrop…
Hole concentration of CuI thin film decreased but Hall mobility increased with the rise of reaction temperature of copper films with iodine vapor. The heat-treatment of CuI film in vacuum brings out the decrease of hole concentration because of the escape of excess iodine from the film. Oxygen diffuses into the bulk o…
Tensile and four-point bend tests on specimens of polycrystalline copper – 8 wt% aluminum coated with mercury have shown that plastic deformation is a necessary precursor to intergranular fracture. The existence of long cracks associated with unfailed notches indicates that a period of stable crack growth precedes fai…
A study has been made of the effects of crystal axis orientation on the slip behaviour, at 1600°K, of compressively deformed uranium dioxide single crystals. It is shown that the critical resolved shear stress for slip is anisotropic, and that the stress is sensitive to ionic configurations at the dislocation core. Th…
This report presents the results of research undertaken with the aim of attaining a better knowledge of flashover mechanism on polluted insulators. Using results already obtained by other authors, the arc development under alternating voltage was studied on an insulating surface of a simple geometry coated with a cond…
The electronic transformer is a device which behaves in the same manner as a conventional power transformer in that it steps voltage levels up or down while providing isolation and can accommodate load current of any power factor. It contains thyristor power switches which convert the low-frequency (dc to 400-Hz) volt…
Associations of planktonic diatom species in four epipelagic environments of the North Pacific have been defined using a recurrent group analysis. The distribution of the groups was related to the physical habitats. Within conservative environments the species associations appear relatively permanent, undergoing minor…
X ray and neutron diffraction analysis may give only limited information about the ordering of the atoms in Heusler alloys. As a first step towards a more systematic interpretation of the experimental data, a procedure which involves the sampling of ordering space at discrete points is described and applied to various…
Abstract The relative compatibility of eight different commercially available elastomers, blended in two-way combinations in three different proportions, was measured as a function of zone size on phase contrast optical micrographs using the Quantimet Image Analyzing Computer. Average cross sectional areas of the disp…
Abstract The migration of small cations into the empty octahedral sites of dioctahedral clays allows one to study the local effects in the trioctahedral structure and the consequences of the exchange capacity decrease on the solvation properties. The results concern essentially the montmorillonite saturated by lithium…
The effect of benzotriazole (BTA) on corrosion of copper in 5% NaCl has been studied by immersion tests, potentiostatic polarization, AC impedance measurements, and ellipsometric investigations. It was found that BTA when present in the corrosive environment is a good inhibitor. The good electronic conductivity of the…
Abstract Heats of fusion, melting transitions, and the derived entropies of fusion were obtained by differential scanning calorimetry for examples from three homologous series of homopolymers having long side chains. Homopolymers having side‐chain lengths between 12 and 22 carbon atoms were chosen from the poly( n ‐al…
An analysis is made of the distribution function and its moments for a linear combination of three randomly chosen orthogonal components of the so-called radius of gyration of an unrestricted random-flight chain, and certain averages of moments are obtained of the three-dimensional distribution W (L12L22L32), where L1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic structure of metallocenesHarry B. Gray, Y. S. Sohn, and N. HendricksonCite this: J. Am. Chem. Soc. 1971, 93, 15, 3603–3612Publication Date (Print):July 1, 1971Publication History Published online1 May 2002Published inissue 1 July 1971https://pubs.acs.org/doi/10.10…
Abstract Heterocysts of Anabaena cylindrica in intact filaments or separated from vegetative cells were examined using improved methods of fixation with glutaraldehyde followed by potassium permanganate or osmium tetroxide. The heterocyst envelope, formed external to the outer layer (LIV) of the pre-existing cell wall…
A simple model of heat flow across a metal-insulator interface is used to calculate the spatial variation of the temperature. The characteristic distance for the temperature gradient to reach its bulk value is shown to be of the order of the phonon mean free path in both the metal and the insulator. Explicit expressio…
Magnetic susceptibility measurements have been made between 4.2 K and 1.1 K on single crystals of Sm, Pr and Nd magnesium nitrate and the measurements are found to obey a Curie law plus a Van Vleck temperature independent term. The results are discussed in terms of wavefunctions obtained with the approximation that th…
Low temperature crystallographic phase transitions in DyVO 4 and TbVO are attributed to a co-operative Jahn-Teller effect. A preliminary report of the theory is given, based on a harmonic oscillator Hamiltonian for the crystal and an electron lattice coupling which is small compared to typical phonon zero point energi…