Materials Literature
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C 14 H 8 S 4 + •I 3 − (I) cristallise dans C2/m avec a=19,831, b=9,266, c=14,515 A, β=90,03 o , Z=6; affinement jusqu'a R=0,0434. C 14 H 8 S 4 + •Cu(NCS) 2 − (II) cristallise dans P1 avec a=8,390, b=9,667, c=12,699 A, α=95,07, β=108,25, γ=112,50 o , Z=2; affinement jusqu'a R=0,142. Dans (I), les ions dibenzotetrafulva…
The magnetic permeability of stoichiometric or non-stoichiometric magnetite (Fe 3- y O 4 ) at high pressures has been measured in a piston-cylinder apparatus. The Verwey transition temperature decrease with pressure at rates of 2.7±0.1 KGPa -1 for y =0.000, 2.49±0.07 for y =0.0051, 2.3±0.1 for y =0.0063, 2.55±0.03 for…
The softening of elastic moduli associated with sliding of a charge-density wave is analyzed in the weak-pinning framework of Lee and Rice. The difference in stiffness between the stationary and sliding states is attributed to the difference in energy between phase configurations that have had time to adjust to the ap…
We present a derivation, based on Green's theorem, of the exact dispersion relation for the electrostatic modes guided by a channel of finite width cut into the otherwise planar surface of a solid in contact with vacuum. The solid, which can be either a metal or a polar dielectric medium, is characterized by a real, i…
First-principles calculations of the surface stress tensor of the aluminum (111) surface are presented that indicate the presence of a tensile stress. We compare our results for aluminum with those for jellium and investigate the origins of the surface stress. At high electron densities, such as that of aluminum, the…
Hole mobilities of binary solid solutions of tri-p-tolylamine and bisphenol-A-polycarbonate have been measured as functions of electric field and temperature for concentrations between 6% and 50% tri-p-tolylamine. The mobilities can be described by an exponential dependence on the square root of the electric field and…
High-quality diamond with good crystallinity has been successfully synthesized on a substrate using an oxy-acetylene combustion flame in the atmosphere. The crystal grains under some conditions have good optical transparency. The deposition rate of transparent diamond depended strongly on substrate temperatures and th…
A numerical model of the filament-assisted diamond growth environment has been developed and used to calculate temperature, velocity, and species concentration profiles, accounting both for transport and detailed chemical kinetics. The computed hydrocarbon concentrations agree well with previously measured values, whe…
We present measurements of the photoexcited states of poly(p-phenylene vinylene), PPV, and a model oligomer, trans,trans-distyrylbenzene, probed by detection of photoluminescence and photoinduced absorption. Photoluminescence is strong in both materials and due to radiative recombination of the singlet exciton. Triple…
Cristallisation dans Pnam avec a=24,591, b=19,757, c=4,166 A, Z=4; affinement jusqu'a R=0,064. La structure est du meme type que la cosalite Pb 4 Bi 4 (Ag, Cu)S 10 , et est composee de rubans constitues de groupements (Pb, Sb)Se 5 de forme pyramidale carree. La distribution des positions atomiques Sb/Pb est determinee…
Prolonged exposure to strongly absorbed light decreases the photoconductivity of well-annealed amorphous chalcogenide (Se, ${\mathrm{As}}_{2}$${\mathrm{Se}}_{3}$, and ${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$) films, similar to the behavior observed in hydrogenated amorphous silicon and organic amorphous polysilanes. This…
SnOx films, made by reactive rf magnetron sputtering onto unheated glass, were studied by electron microscopy, Hall-effect measurements, and Mössbauer spectrometry. Transmission electron microscopy showed that the films were polycrystalline with a grain size of ∼15 nm. Hall-effect measurements gave a sharp resistivity…
Thermal conductivity data of polycrystalline chemical vapor deposited cubic silicon carbide are calculated from thermal diffusivity and heat capacity data in the temperature region of 80–300 K. Below 200 K, a linear dependence of the thermal conductivity with the product of grain size of the silicon carbide and cubic…
A method is described that enables the simultaneous or consecutive determination of the specific heat, the thermal diffusivity, the dielectric constant, and the pyroelectric coefficient of thin pyroelectric films. The sample is heated by the absorption of intensity modulated light at one surface. The pyroelectric curr…
Methods for the determination of the frequency dependent hyperpolarizabilities, β(−2ω;ω,ω), β(−ω;ω,0), and β(0;ω,−ω) at the self-consistent field (SCF) level of theory are discussed and compared. Two efficient alternatives are proposed; one involves determination of appropriate response vectors which arise in first-or…
The objective of this research is to establish a shape-memory effect in sputter-deposited films of nickel titanium. The alloy, generically called nitinol, was prepared from sputtering targets in two different compositions. Films were deposited up to 10 μm in thickness on glass substrates using a dc magnetron sputterin…
The electronic properties of tin dioxide single-crystalline (110) surfaces have been studied in correlation with their structure by low-energy electron diffraction, angle-integrated and resonant photoemission using synchrotron radiation [ultraviolet photoemission spectroscopy (UPS)]. Energy distribution curves were me…
Full phonon-dispersion curves of the graphitic layer on some transition-metal carbides were measured by using high-resolution electron-energy-loss spectroscopy. The graphitic layer on (111) surfaces of TaC, HfC, and TiC showed anomalous softening within the layer, whereas the graphite layer on TaC(001) is similar to b…
A physically based methodology is developed for modeling the behavior of electrical circuits containing nonideal ferroelectric capacitors. The methodology is illustrated by modeling the discrete ferroelectric capacitor as a stacked dielectric structure, with switching ferroelectric and nonswitching dielectric layers.…
We study electron-phonon coupling in the case of Fr\"ohlich or polar interaction, with special emphasis on the size dependence of the coupling strength for semiconductor nanospheres exhibiting quantum confinement of the carriers. We first derive the expression of the vibrational LO (longitudinal optic) and SO (surface…