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CARBON-13 NMR STUDIES OF LIQUID CRYSTALS

High resolution, proton decoupled {sup 13}C nmr are observed for a series of neat nematic liquid crystals, the p-alkoxyazoxybenzenes, and a smectic-A liquid crystal, diethylazoxydibenzoate in a magnetic field of 23 kG. The (uniaxial) order parameters S = <P{sub 2}(cos{theta})> are found to be about 0.4 and 0.9 for the nematic and smectic-A phase respectively at the clearing points. The order parameter increases with decreasing temperature in the nematic phase but is constant, or nearly so… more

Date: June 1, 1975

Creator: Allison, Stuart

Partner: UNT Libraries Government Documents Department

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Applications of time-differential perturbed angular correlations to the study of solids

Time-differential perturbed angular correlation techniques were applied to a systematic study of insulating antiferromagnets and rare-earth intermetallic alloys doped with either /sup 111m/Cd or $sup 111$In. The internal magnetic fields and electric field gradients at the radioactive nucleus are deduced from the experimentally measured perturbation factors. The analysis of fluoride, chloride, oxide, and sulfide data shows the systematic variation of the observed supertransferred hyperfine field… more

Date: June 1, 1975

Creator: Schwartz, G.P.

Partner: UNT Libraries Government Documents Department

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Finite element method for neutron diffusion problems in hexagonal geometry

The use of the finite element method for solving two-dimensional static neutron diffusion problems in hexagonal reactor configurations is considered. It is investigated as a possible alternative to the low-order finite difference method. Various piecewise polynomial spaces are examined for their use in hexagonal problems. The central questions which arise in the design of these spaces are the degree of incompleteness permissible and the advantages of using a low-order space fine-mesh approach o… more

Date: June 1, 1975

Creator: Wei, T. Y. C. & Hansen, K. F.

Partner: UNT Libraries Government Documents Department

open access

Coupled MHD-Monte Carlo transport model for dense plasmas

A two-dimensional, two fluid model of the MHD equations has been coupled to a Monte Carlo transport model of high energy, non-Maxwellian ions. The MHD part of the model assumes complete ionization and includes a perfect gas law for a scalar pressure, a tensor artificial viscosity, electron and ion thermal conduction, electron-ion coupling, and a radiation loss term. A simple Ohm's Law is used with a B/sub theta/ magnetic field. The MHD equations were solved in Lagrangian coordinates. The conser… more

Date: June 1, 1975

Creator: Chandler, W.P.

Partner: UNT Libraries Government Documents Department