Materials Literature
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Measurements of the first-order Raman spectrum in natural type-IIa diamond for the temperature range of 293 to 1850 K are presented. Both the Stokes and anti-Stokes components are analyzed for their intensity, Raman shift, and width variation with temperature. Optical pyrometry was used to make the temperature measure…
New developments involving nonlinear optical effects are conditioned by the improvement of pertinent figures of merit involving the characteristics of nonlinear optical materials within the ‘‘transparency’’ regime of their optic windows. This paper discusses, from a global standpoint, the maximum values of nonlinear r…
The temperature dependence of the zone-center optical phonon of diamond has been investigated up to 1900 K using Raman scattering. Our frequencies agree well with the first measurements of the temperature dependence of this mode but are found to fall halfway between those obtained in two later determinations up to 100…
The crystal structures of mitochondrial aconitase with isocitrate and nitroisocitrate bound have been solved and refined to R factors of 0.179 and 0.161, respectively, for all observed data in the range 8.0-2.1 A. Porcine heart enzyme was used for determining the structure with isocitrate bound. The presence of isocit…
We have performed a resonant photoemission study on both stoichiometric and reduced ${\mathrm{TiO}}_{2}$ (110) surfaces using synchrotron radiation. A resonant enhancement of the O 2p valence-band photoemission intensity is observed for both stoichiometric and reduced ${\mathrm{TiO}}_{2}$ surfaces as the photon energy…
The bond-orbital theory of linear and nonlinear electronic response in optically transparent materials, developed earlier for pretransition-metal halides and chalcogenides, is expanded to embrace the transition-metal (TM) oxides. The extension requires an explicit recognition of the influence of cationic empty d orbit…
The nonlinear electric and electromechanical responses of lead zirconate titanate Pb(ZrxTi1−x)O3 ceramics to an external ac electric field have been measured under different driving levels. The onset of measurable nonlinearity is observed to be accompanied by the appearance of hysteresis loops. This lossy nature sugge…
An analysis of x-ray diffraction line shape and Raman-scattering results shows that single-molecular-layer ${\mathrm{MoS}}_{2}$, prepared by exfoliation of lithium-intercalated ${\mathrm{MoS}}_{2}$ powder in water, has a structure in which the Mo atoms are octahedrally coordinated, in contrast to the trigonal prismati…
A new degradation analysis of ZnO-based varistors by AC impedance measurements is presented. From these measurements, which have been achieved on samples as a response to a small signal in the frequency range 10 -3 to 10 5 Hz, at room temperature, the distribution function of the relaxation time constant has been dedu…
The photoinduced phase transition of nematic liquid crystalline (LC) emulsions containing 4-n-butyl-4'-methoxyazobenzene (BMAZ) was studied in a polyvinylalcohol (PVA) film as a supporting medium. Phase transition was reversible and accompanied by a large change in transmittance as well as a change in birefringence. P…
The drift and longitudinal diffusion of SF 5 - and SF 6 - in SF 6 has been studied with a drift-tube mass spectrometer. Values of the reduced mobility and of the density-normalized longitudinal diffusion coefficient of these ions are reported over the combined E/N range 15-460 Td. The present zero-field reduced mobili…
Tin oxide (SnO x ) films have been deposited using a RF magnetron sputtering technique from a hot pressed SnO 2 target in an ambient mixture of argon and oxygen. Depending on the deposition parameters the structure of the films may be varied from amorphous to crystalline along with a consequent decrease in resistivity…
X-ray photoelectron spectroscopy has been used to investigate the atomic species, and their bonding, within the conductive polymer polyaniline (PANi). PANi was grown electrochemically using HCl as the electrolyte ion and all three of PANi's oxidation states were investigated. Measurements of the C 1s, N 1s, O 1s and C…
X-ray scattering studies of (N(CH 3 ) 4 ) 2 MnCl 4 under pressure reveal strong indications of the existence of several new commensurate phases with long periods. The wave vectors of these phases are found to constitute a set of the Farey-tree series. Structure branching and other features in the observed P-T phase di…
We have studied the coarsening dynamics of line defects in the uniaxial nematic liquid crystal 4-cyano-4'-n-pentylbiphenyl, subjected to a rapid pressure jump from the isotropic to the nematic phase. At late times, the density of disclination lines \ensuremath{\rho} is expected to scale with time as \ensuremath{\rho}\…
An overall survey of the structural and magnetic features of the La 2 NiO 4+ delta system is presented as a result of neutron diffraction experiments. The stoichiometric compound ( delta =0) presents two structural phase transitions. At T 0 approximately=770 K, La 2 NiO 4 transforms from tetragonal (I4/mmm) to orthorh…
For the first time, the fabrication of a periodically reversed domain structure for LiNbO3 has been achieved at room temperature. The domain boundary is perpendicular to the positive c-face and is very deep which is advantageous for quasiphasematching SHG.
A semiclassical interatomic potential for carbon is discussed which is based on the proximity cell (the Wigner-Seitz cell) around each atom. It introduces three internal degrees of freedom per atom, representing the magnitude and direction of the p orbital that is not involved in sp hybridization. Its direct interpola…
By means of hyper-Raman scattering, a silent soft phonon was observed in \ensuremath{\beta}-quartz for the first time. The soft phonon was found to become underdamped at high temperatures. Both the square of the frequency ${\mathrm{\ensuremath{\omega}}}_{0}^{2}$ and the integrated intensity ${\mathit{I}}_{0}$ of the s…
Ceramic layer epitaxy, defined as the epitaxial growth of ceramic thin films with thicknesses regulated on an atomic scale, was verified by a new method using pulsed laser deposition in ultrahigh vacuum (UHV). The intensity oscillation of reflection high-energy electron diffraction (RHEED) was observed in an ArF excim…