Materials Literature
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We study single hole motion in LaMnO$_3$ using the classical approximation for JT lattice distortions, a modified Lang-Firsov approximation for dynamical breathing-mode phonons, and the self-consistent Born approximation (verified by exact diagonalization) for hole-orbital-excitation scattering. We show that in the re…
Crack formation is conventionally described as a nucleation phenomenon despite the fact that the temperatures necessary to overcome the nucleation barrier are far too high. In this paper we consider the possibility that cracks are created due to the presence of frozen disorder (e.g., heterogeneities or frozen dislocat…
We report fluctuation magnetoconductance in a MgB2 superconductor prepared under a high pressure of 3 GPa. This excess magnetoconductance, $Δσ(H)$, follows the three-dimensional scaling function for the critical fluctuations proposed by Ullah and Dorsey. This feature is inferred to originate from the isotropic nature…
Mesoporous Ta 2 O 5 was synthesized by the ligand-assisted templating method, and its stability for use as a photocatalyst was studied by X-ray diffraction, N 2 adsorption isotherm analysis, and transmission electron microscopy. The photocatalytic activity for the overall water decomposition on the mesoporous Ta 2 O 5…
The effects of the electron-electron interactions in a graphene layer are investigated. It is shown that short-range couplings are irrelevant and scale towards zero at low energies, due to the vanishing of density of states at the Fermi level. Topological disorder enhances the density of states and can lead to instabi…
A model of NMR spin-lattice relaxation in quasicrystals is presented, which takes into account two important quasicrystals-specific features: (i) the critical nature of the electronic states and (ii) the phonon-assisted hopping nature of electronic conduction within the self-similar quasiperiodic structure of hierarch…
A computer simulation study has been performed to investigate the intrinsic defects in ${\mathrm{PbWO}}_{4}$ (PWO). The interatomic potentials were empirically fit to the known crystal properties. Calculations reveal that PbO nonstoichiometry dominates the intrinsic defects in PWO, whereas the oxygen Frenkel defects w…
By using a Raman microscope, we show that it is possible to probe the conformational states in protein crystals and crystal fragments under growth conditions (in hanging drops). The flavin cofactor in the enzyme para-hydroxybenzoate hydroxylase can assume two conformations: buried in the protein matrix ("in") or essen…
Water, benzene, and nitrogen were adsorbed on Al-MCM-41 molecular sieves, both unmodified and modified via controlled deposition of coke, and adsorption isotherms were determined. The mechanism of adsorption most probably includes multilayer adsorption at lower relative pressures, followed by capillary condensation. I…
We present a simple Fokker-Planck model for the evolution of the number of atoms and the spatial distribution in a ${\mathrm{CO}}_{2}$ laser trap which is loaded from a magneto-optical trap (MOT). Deep ${\mathrm{CO}}_{2}$ laser traps can achieve very high densities, but reach equilibrium slowly compared to shallow tra…
Mesoscopic hollow spheres of ceramic materials whose interior surfaces were functionalized by nanoscopic objects were generated by templating sol−gel precursors against three-dimensional arrays of polystyrene beads whose surfaces had been derivatized with submonolayers of the nanoscopic objects.
The ${\mathrm{Bi}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ system is known to exhibit charge ordering for a much broader range of x than the ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ system. However, the properties of ${\mathrm{Bi}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm…
The electrical resistivity, thermoelectric power and electronic thermal conductivity of simple (isotropic) metals are studied in a uniform way. Starting from results of a variational solution of the Boltzmann equation, a generalized Matthiessen rule is used in order to superpose the inelastic (or not) electron-phonon…
Nanotubular materials inspired by crystalline diborides such as AlB_2 are proposed. The atomic structure, in particular the basic chemical question of where to put Al atoms in order to stabilize nanotubular Al-B systems, is investigated using density-functional calculations for prototype systems. The optimized tubular…
A first-principle theory for the effective dielectric permittivity in metallic mesostructures is developed. This theory, in particular, takes into account the skin effect, which is important in practical applications of metal structures.
<div class="htmlview paragraph">Recently, ASMT has developed a process of making monolithic metal oxide thin-wall structures from mechanically assembled metal preforms, whose shape and internal configuration are retained in the (oxidation) process. Because metallic designs can be extremely diverse, the same vari…
This paper describes the third generation of the partial zero emission vehicle (P-ZEV) technology originally adopted on the Nissan Sentra CA sold in California. The 2000 Nissan Sentra CA became the world's first gasoline-fueled car to qualify for P-ZEV credits from the California Air Resources Board (CARB). The third-…
Two effects of rich-spike duration on NOx-storing have been analyzed. The first one, that NOx-storing speed decreases as rich-spike duration increases, is explained as the influence of NOx diffusion in wash-coat layer, which is quantified by a simple mathematical expression for NOx-storing rate. The second one, a pecu…
<div class="htmlview paragraph">Recent developments in design of composite armor for lightweight ground vehicle applications is discussed. Composite integral armor (CIA) is a multi-functional hybrid material system that has been successfully demonstrated in the Composite Armored Vehicle. A typical CIA hull consi…
<div class="htmlview paragraph">Strict legislation standards for automotive emission limits (e.g. ULEV, SULEV), which target for HC conversion rates beyond 99 %, impose the necessity to dramatically shorten catalyst Light-Off time and increase catalytic efficiency through improved catalytic converter heat-up. Es…