Materials Literature
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The gaseous equilibria MCl+Ag=M+AgCl and M+MCl2=2 MCl, where M=Cr, Mn, Fe, Co, and Ni were studied by mass spectrometry in the region around 1500 K, and thermochemical data were derived by second and third law methods. Dissociation energies of the metal monochlorides were evaluated by reference to AgCl, leading to the…
We present data on the dielectric relaxation in the random copolymer polybutadiene. There are two distinct peaks in the imaginary part of the dielectric susceptibility, one of which is attributable to an \ensuremath{\alpha} relaxation and the other to a Johari-Goldstein \ensuremath{\beta} relaxation. The bifurcation o…
Thermoelectric cooling, based upon the extraction of hot electrons and holes from a metallic electron gas, holds unrealized potential for refrigeration at cryogenic temperatures. We discuss the performance of two such electronic refrigerators: the quantum-dot refrigerator (QDR) and the normal-insulator-superconductor…
Abstract Short pineapple‐leaf‐fiber‐(PALF)‐reinforced low‐density polyethylene (LDPE) composites were prepared by melt‐mixing and solution‐mixing methods. In the melt‐mixing technique, a mixing time of 6 min, rotor speed of 60 rpm, and mixing temperature of 130°C were found to be the optimum conditions. Tensile proper…
We present a method for electronic-structure calculations based on the finite-element method. In this method all the calculations are performed in real space and the use of nonuniform mesh is possible. As a result, localized systems such as transition metals can be treated with ease, and even all-electron calculations…
The cap of a carbon nanotube is characterized by six five-membered rings called disclinations. Its electronic structure is studied by the simple tight-binding models for a monolayer nanotube. The method of the development map is used to systematically define the atomistic structures of the cap. The topological feature…
Electronic states of κ-(ET) 2 X are studied theoretically. The effects of the on-site Coulomb interaction and dimer structure have been explored at absolute zero within the Hartree-Fock approximation. If Coulomb interaction exceeds some critical value, localized spins which are antiferromagnetically ordered within a u…
We computer generate a model of amorphous diamond using the Wooten-Weaire method, with fourfold coordination everywhere. We investigate two models: one where four-membered rings are allowed and the other where the four-membered rings are forbidden; each model consisting of 4096 atoms. Starting from the perfect diamond…
Diamond samples with varying defect densities have been synthesized by chemical vapor deposition, and their field emission characteristics have been investigated. Vacuum electron field emission measurements indicate that the threshold electric field required to generate sufficient emission current densities for flat p…
Near-edge and extended x-ray-absorption fine-structure measurements from a wide variety of oxidized Si nanocrystals and H-passivated porous Si samples, combined with electron microscopy, ir absorption, forward recoil scattering, and luminescence emission data, provide a consistent structural picture of the species res…
Quantum-confined Stark effects (QCSE) on excitons, i.e., the influence of a uniform electric field on the confined excitons in semiconductor quantum dots (QD's), have been studied by using a numerical matrix-diagonalization scheme. The energy levels and the wave functions of the ground and several excited states of ex…
A recently proposed linear-scaling scheme for density-functional pseudopotential calculations is described in detail. The method is based on a formulation of density functional theory in which the ground state energy is determined by minimization with respect to the density matrix, subject to the condition that the ei…
The switching of the sandwich structure ‘‘ferroelectric+thin dielectric layer’’ is theoretically studied. The behavior of the remanent polarization, Pr, coercive field, Ec, maximal polarization on the loop, Ps, and the slope of the hysteresis loop at Ec as a function of both, the relative thickness of the layer (the t…
Crystal structures and magnetic properties for off-stochiometric R 2 Fe 14 Ga 2 (R=Y, Nd and Sm) have been studied by using X-ray diffraction, magnetic measurements and Mossbauer spectra. All compounds have the Tb 2 Zn 17 structure. The Curie temperatures increase by about 150-200 degrees C over those for the correspo…
The proposed continuum model describes thin film nucleation and growth from a unique point of view for the whole region of supersaturations (both the metastable region of small supersaturations and the unstable region of high supersaturations). The early stage of thin-film formation is presented as a relaxation proces…
Glycine-124 and leucine-307 of phenylalanine dehydrogenase from Bacillus sphaericus were altered by site-specific mutagenesis to the corresponding residues in leucine dehydrogenase: alanine and valine, respectively. These two residues have previously been implicated from molecular modelling as important in determining…
The motion of charged particles in electric fields can be harmful to gas-insulated apparatus, or may be used beneficially in several electrostatic technologies, such as printing, coating and separation of mixed granular solids. The theoretical analysis and the experimental data demonstrate the existence of numerous fa…
Equilibrium molecular dynamics is used to simulate fluids comprised of chains of tangent hard spheres. Reptation theory predictions of segmental motion are compared with simulation results. In addition to the usual tube confinement, a second entanglement effect is observed. As the chain disengages from the tube, persi…
Surface freezing of a crystalline monolayer has been observed at the free surface of liquid binary mixtures of normal alkanes by x-ray and surface tension measurements. Two dramatically different behaviors are found for the monolayer properties depending on $\ensuremath{\Delta}n$, the difference in the components' car…
The incorporation of hydrogen into Si, under different electrochemical conditions including anodization in fluoride solutions where porous silicon is formed, is studied by NRA and in situ capacitance measurements. Results suggest a large near surface concentration of H whilst simulation show that the maximum penetrati…