Materials Literature
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The equilibrium lattice parameters, bulk modulus, shear elastic constant ${C}_{44}$, and cohesive energy of GeTe are calculated with use of the ab initio scalar relativistic pseudopotential in the local-density approximation. The convergence of the structural properties in basis-set size and Brillouin-zone averaging i…
The first-order phase transitions among the hydration states in both Na and Ca vermiculites are studied by water-adsorption isotherm and specific-heat measurements. These compounds have three kinds of hydration states defined by the number of water layers in the interlamellar space between the silicate layers (0-, 1-,…
We have performed restricted Hartree-Fock self-consistent-field calculations on BeO and MgO clusters embedded in a point-charge field (chosen to represent the Madelung field in BeO and MgO crystals) in order to understand better the role of the many contributory shifts to the ionization potentials which occur for atom…
Acoustic-phonon transmission through a realistic Fibonacci superlattice is studied theoretically. We find a number of transmission dips corresponding to Bragg-like reflections of phonons. The transmission spectrum is much more complex than in the periodic case; however, the strongest dips in transmission are remarkabl…
X-ray diffraction measurements up to momentum transfer q=16 Å−1 were performed at atmospheric pressure on both the high-density form of amorphous ice obtained by pressurization of crystalline ice Ih at 77 K up to 2 GPa and the low-density form obtained by further heating. These two amorphous phases exhibit significant…
Within the framework of a one-dimensional continuous Ginzburg-Landau theory, pulselike solitary waves in shape-memory alloys are investigated. By neglecting heat conduction, internal friction, and external volume forces, but including shear-strain and strain-gradient contributions in addition to the Landau internal en…
The effects of In impurity on the dynamic behavior of dislocations in GaAs crystals are investigated in comparison with those of Si impurity. Indium, even at a concentration of the order of 1020 cm−3, is found to affect the velocity of moving dislocations only slightly while Si impurity at a concentration of the order…
Dielectric relaxation measurements covering a wide frequency range extending from 10−6 to 106 Hz were made on poly(vinyl acetate) with conventional glass transition temperature Tg of 31 °C at temperatures between 26.85 and 84.77 °C. It was found that temperature dependence of frequency of the maximum dielectric loss b…
This paper describes analyses and confirming experiments on the optimum temperature for fast response in nematic liquid crystal (LC) modulators. It is demonstrated that the LCs or LC mixtures with higher nematic-isotropic phase transition temperatures have higher optimum temperatures and greater potential for improvin…
High-density amorphous water is studied by neutron scattering in a Q range extending to 16 Å−1. The low density form of amorphous water is also analyzed and compared with previous results. There are very important differences in the composite pair correlation functions of the two forms of amorphous ice, in particular…
An experimental study of the temperature- ($T$) dependent dc conductivity $\ensuremath{\sigma}$, the electric field ($E$) dependence of $\ensuremath{\sigma}$, and the $T$-dependent thermopower $S$ as a function of protonation level ($0.0<x\ensuremath{\equiv}\frac{[{\mathrm{H}}^{+}]}{[\mathrm{N}]}\ensuremath{\leqq}0…
We have measured the kinetics of the methane decomposition reaction on Ni(111), Ni(100), and Ni(110) single crystal surfaces under the high incident flux conditions of 1 Torr methane. We find for these processes apparent activation energies of 12.6, 6.4, and 13.3 kcal mol−1, respectively. Initial methane sticking coef…
We discuss the influence of experimental conditions in the analysis of the infrared reflectivity due to lattice modes in bulk single crystals of \ensuremath{\alpha}-${\mathrm{LiIO}}_{3}$ and \ensuremath{\alpha}-quartz. The analysis leads to the appearance of additional bands in the usual off-normal incidence of the in…
The intensity of the Raman-active ${\ensuremath{\Gamma}}_{25\mathcal{'}}$ mode of nanometer-sized crystalline silicon, nc-Si, normalized to that of calcium fluoride, ${\mathrm{CaF}}_{2}$, at 322 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ was measured for samples deposited under controllably varied conditions. Changes…
Gold and silicon are almost completely immiscible in the solid state. They form a simple eutectic at about T =
It is found that the characteristic infrared spectra of thermally grown silicon dioxide in the 1075 cm−1 region for films in the thickness range 28–450 Å mathematically deconvolute consistently into two distinctly separate Gaussian profiles. The derived peaks are found around 1050 cm−1 with a full width at half-maximu…
A neutron-diffraction experiment (\ensuremath{\lambda}=0.704 A\r{}) has been performed for the first time on liquid arsenic above the triple point. The coordination number (Z=3) does not change through the semimetal-to-semiconductor transition on melting. This is in sharp contrast to the elemental semiconductors (Si,G…
The ultrasonic velocity and absorption of 32 silicate melts have been determined as a function of temperature (1175–1925 K) and frequency (3–12 MHz). The samples include the components SiO 2 , TiO 2 , Al 2 O 3 , FeO, MgO, CaO, SrO, BaO, Li 2 O, Na 2 O, K 2 O, Rb 2 O, and Cs 2 O, and range from simple alkali silicates…
A constant thermodynamic tension Monte Carlo method is introduced and applied studies of the elastic properties of a two-dimensional system of hard cyclic hexamers. Elastic compliances and elastic constants are determined at a number of different values of the pressure. The existence of the phase transition between a…
The magnitude and temperature dependence of most of the properties of amorphous solids are anomalous at very low temperatures ( less, similar1 Kelvin). Phonon-assisted tunneling of a distribution of glassy bistable configurations, or two-level systems, can account for these anomalies. A unified understanding of the lo…