Materials Literature
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Expressions are derived for the effective phonon deformation potentials of polycrystalline materials, based on the properties of tensor invariants and the Voigt–Reuss–Hill averages [Proc. Phys. Soc. London Sect. A 65, 349 (1952)]. These results, and similar ones for the elastic constants, are used to determine the eff…
A completely ab initio theoretical investigation of the rocksalt-rhombohedral structural phase transition of GeTe is described. Starting from an anharmonic lattice Hamiltonian, a model Hamiltonian that includes coupling of the order parameter to long-wavelength strain is constructed. The parameters appearing in the mo…
We present results for the band structure, charge density, and total-energy-related quantities such as equilibrium lattice constants, bulk moduli, and TO-phonon frequencies for a variety of different semiconducting materials, using a simple ab initio self-consistent linear combination of pseudo-atomic-orbital scheme (…
The present work employs the total-energy pseudopotential technique to calculate the relative stabilities at high pressures of the zinc-blende \ensuremath{\beta}-Sn, and rocksalt structures in the series of compounds BN, BP, and BAs. For compressed volumes these compounds are shown to favor the rocksalt phase over \en…
Accurate full-potential self-consistent linearized augmented-plane-wave (FLAPW) calculations have been carried out for hexagonal boron nitride. The resulting energy-band structure indicates that this material is an indirect-gap insulator and shows the existence of two unoccupied interlayer bands, similar to those foun…
On the basis of a simple functional scaling, we have constructed the direct generalization of the Carnahan–Starling equation for the free energy of a hard sphere fluid to a nematic liquid crystal. The orientational degrees of freedom are completely decoupled from translational ones under that scaling, which is equival…
A phenomenological thermodynamic theory of PbTiO3 was developed using a modified Devonshire form of the elastic Gibbs free energy. The spontaneous strain as a function of temperature was determined from pure sol-gel derived PbTiO3 powder and used with selected data from the literature to determine the coefficients of…
The dielectric properties, such as the real in ' and imaginary in " parts of the complex permittivity and the spontaneous polarisation P s of single-crystal and ceramic Pb(Co 1/3 Nb 2/3 )O 3 with a diffuse phase transition (DPT), were measured under various pressures up to 6 kbar. The value of in ' shows a broad maxim…
Absolute total cross section measurements are presented for e - -Ne and e - -Ar scattering. The covered energy range spans from 100 to 3000 eV. The overall systematic uncertainty was +or-2.4%, the random uncertainty was +or-1.5% and the angular resolution error was less than 0.5%. A comparison with existing experiment…
The end-to-end vector relaxation time, \ensuremath{\tau}, and center-of-mass diffusion constant, D, of a nonintersecting chain with nearest-neighbor attractive interactions were investigated. Data were obtained by Monte Carlo simulation of motion as a function of temperature in the free-draining approximation. The ran…
A hybrid aligned cholesteric (HAC) liquid-crystal (LC) structure is reported. The LC director tilt varies from a small angle at one surface to almost 90° at the other, while incorporating a helical twist. Cells having one surface treated with rubbed polyvinyl alcohol and the other with the organosilane octadecyltrieth…
The detailed structural changes that occur during the isothermal transition from a glass to a single-phase crystalline solid have been determined for the first time by use of the modern technique of high-performance liquid chromatography. Quantitative measurements of the evolution of the type and relative concentratio…
Axial absorption and circular dichroism (CD) spectra are reported for single crystals of Na3[Sm(oxydiacetate)3]·2NaClO4·6H2O over the spectral region 17 600–30 500 cm-1. Within this region, 213 individual (4f → 4f) crystal-field transitions may occur from the ground crystal-field level of Sm3+. Each of these transitio…
A p-n junction diode of cubic boron nitride was made by growing an n-type crystal epitaxially on a p-type seed crystal at a pressure of 55 kilobars and a temperature of about 1700 degrees C. A temperature-difference solvent method was used for the crystal growth, and beryllium and silicon were doped as acceptors and d…
Abstract Optical absorption and fluorescence, magnetic susceptibility and electron magnetic resonance experiments have been made of Tb3+, 4f8, ions in lanthanide nicotinate dihydrate single crystals. Optical absorption spectroscopy in undiluted terbium nicotinate dihydrate (TbND) indicates that the ground state of Tb3…
Abstract The stability of superspheres containing a few tens of particles, formed by the aggregation of weakly charged spherical colloidal crystalites, can be explained by the existence of two opposing forces of different range within the superspheres: long-range electrostatic repulsion and shortrange attractive dispe…
Abstract A set of transformed composition variables is introduced for the representation of reactive-phase diagrams. These variables are superior to mole fractions because in the new representation, the non-reactive limits are well defined, the equilibrium surfaces are tangent at azeotropic states, and the number of l…
Article Neutron diffraction study of zoisite at 15 Κ and X-ray study at room temperature was published on October 1, 1987 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 179, issue 1-4).
Article Ruthenium(III)triphosphide RuP3: Preparation, crystal structure and properties was published on October 1, 1987 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 179, issue 1-4).
Space charge may lower the breakdown strength of solid insulation by making local electric fields bigger than the applied field. One extensive study[1] of this phenomenon led to a proposal to blend crosslinked polyethylene (XLPE) insulation with an ionomer to reduce space charge build-up. The authors used contact elec…