Materials Literature
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In this paper we present a Path Integral Monte Carlo (PIMC) simulation of the orthorhombic phase of crystalline polyethylene, using an explicit atom force field with unconstrained bond lengths and angles. This work represents a quantum extension of our recent classical simulation (J. Chem. Phys. 106, 8918 (1997)). It…
Thin films of perovskite manganite La0.7Ca0.3MnO3 were grown epitaxially on SrTiO3(100), MgO(100) and LaAlO3(100) substrates by the pulsed laser deposition method. Microscopic structures of these thin film samples as well as a bulk sample were fully determined by x-ray diffraction measurements. The unit cells of the t…
We present measured dielectron production cross sections for $\mathrm{Ca}+\mathrm{Ca}$, $\mathrm{C}+\mathrm{C}$, $\mathrm{He}+\mathrm{Ca}$, and $d+\mathrm{Ca}$ reactions at $1.0\phantom{\rule{0ex}{0ex}}A\mathrm{GeV}$. Statistical uncertainties and systematic effects are smaller than in previous dilepton spectrometer (…
Anisotropy of electrical and optical properties in β-Ga2O3 single crystals has been investigated at room temperature. The conductivity and mobility of the degenerate sample along the direction of b and c axes are 38 Ω−1 cm−1, 46 cm2 V−1 s−1, and 2.2 Ω−1 cm−1, 2.6 cm2 V−1 s−1, respectively. The absorption edges of the…
Elastic properties of carbon nanotubes and nanoropes are investigated using an empirical force-constant model. For single and multiwall nanotubes the elastic moduli are shown to be insensitive to structural details such as the helicity, the radius, and the number of walls. The tensile Young's modulus and the torsion s…
45-degree rotated epitaxial diamond nucleation on both (001) and {111} planes of a silicon substrate was observed using chemical vapor deposition with nucleation enhancement by electron emission. The epitaxial relationship between diamond and Si is D(001)//Si(001) and D<100>//Si<110> in both cases. While the case of d…
Dicaesium trimanganese tetratelluride, Cs2Mn3Te4, has been synthesized at 1173 K and its structure determined from single-crystal X-ray data. Cs2Mn3Te4 is isostructural with Cs2Mn3S4. The structure comprises layers of edge-sharing manganese-centered tetrahedra stacked perpendicular to [001].
Mercury(II) diphosphate, Hg2P2O7, belongs to the M2X2O7 family of compounds with dichromate-type crystal structures and is isotypic with Cd2P2O7. It consists of alternating layers built from P2O7 groups and highly distorted HgO6 polyhedra with bond distances in the ranges 2.120 (6) ≤ d(Hg1O6) ≤ 2.793 (7) Å and 2.208 (…
The magnetoresistance of a quasi-one-dimensional (Q1D) organic superconductor, (DMET) 2 I 3 , where DMET is dimethyl(ethylenedithio)diselenadithiafulvalene, was measured up to 30 T at 1.5 K. An electrical current was applied perpendicular to the conducting a b plane and a magnetic field is rotated in the a b plane. An…
The column densities of several molecular radicals are measured in an oxyacetylene torch flame during the growth of diamond films. The column densities of CH, C2, CN, and OH radicals are determined by highly sensitive absorption spectroscopy. The radical densities are measured as a function of position in the flame fo…
Properties of ordered group-IV compounds containing carbon, silicon, and germanium are calculated within the local density approximation. Twenty-seven fully relaxed compounds represented by seven different compound structures are compared and, with the exception of SiC, all compounds are found to be metastable. Two tr…
Upconversion by two-ion energy transfer, two-photon absorption (TPA), and stepwise absorption processes has been reported for ${\mathrm{Er}}^{3+}$ in cubic ${\mathrm{Cs}}_{2}{\mathrm{NaYCl}}_{6}$ crystal. Blue emission from the ${}^{2}{G}_{9/2}$ and green emission from the ${}^{4}{S}_{3/2}$ state have been observed un…
The sharp component observed in the critical scattering above the cubic-to-tetragonal phase transition in SrTiO 3 is now generally considered as a surface-related phenomenon. In the present paper, for the first time, the structural difference between the bulk and a skin layer of a highly perfect crystal has been shown…
Aromatic polyesters were prepared and used to improve the brittleness of the bismaleimide resin composed of 4,4′-bismaleimidediphenyl methane and o,o′-diallyl bisphenol A. The aromatic polyesters contain poly(ethylene phthalate) (PEP) and poly(ethylene phthalate-co-ethylene isophthalate) (10 mol % isophthalate unit) (…
We have studied the electronic and structural properties of native defects in cubic boron nitride (nitrogen vacancy, boron antisite, and oxygen substitutional) using all-electron first-principles total-energy calculations. We find that all defects introduce a deep state above the middle-energy gap. These defects prese…
The spin dynamics of La 1- x Sr x MnO 3 for Sr concentrations of x ≤0.3 were studied by inelastic neutron scattering. For the entire concentration range studied, we found that the spin-wave stiffness constant D and the paramagnetic spin-diffusion constant A * are ruled by the nearest neighbor interaction, i.e., the st…
${\mathrm{C}}_{3}{\mathrm{N}}_{4}$ films were prepared on Si(111) by rf plasma-enhanced chemical vapor deposition using ${\mathrm{Si}}_{3}{\mathrm{N}}_{4}/\mathrm{T}\mathrm{i}\mathrm{N}$ and ${\mathrm{Si}}_{3}{\mathrm{N}}_{4}/\mathrm{Z}\mathrm{r}\mathrm{N}$ as transition layers. X-ray diffraction and transmission elec…
Hysteresis loss of natural rubber (NR) and styrene–butadiene rubber (SBR) vulcanizates having variations of loading of carbon black, silica, clay, resin, and curatives has been measured over a wide range of strain rates and temperatures as well as under swollen conditions. Hysteresis loss increases with an increase in…
The room-temperature wall energy σw=4.0×10−3 J/m2 of an exchange-coupled Tb19.6Fe74.7Co5.7/Dy28.5Fe43.2Co28.3 double layer stack can be reduced by introducing a soft magnetic intermediate layer in between both layers exhibiting a significantly smaller anisotropy compared to Tb–FeCo and Dy–FeCo. σw will decrease linear…
Composites with high relative magnetic permeability values can be used in many industrial applications, especially if they can be shaped using conventional polymer-processing technologies. In this study, various hybrid composite systems (i.e., particles with differing aspect ratio, size, and magnetic permeability embe…