Materials Literature
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Nanocrystalline barium titanate particles are prepared by the alkoxide method. The lattice constants are obtained from the electron diffraction patterns for various orientations of single particles in the size range of 15--250 nm in diameter. The present result indicates that the structural change from a tetragonal (f…
We present calculations of energetic, electronic, and vibrational properties of silicon using a nonorthogonal tight-binding (TB) model derived to fit accurately first-principles calculations. Although it was fit only to a few high-symmetry bulk structures, the model can be successfully used to compute the energies and…
The oxide film on magnesium offers considerable surface protection in rural and some industrial environments and the corrosion rate lies between that of aluminum and low carbon steels. Galvanic coupling of magnesium alloys, high impurity content such as Ni, Fe, Cu and surface contamination are detrimental for corrosio…
Colony PCR and semi-nested PCR techniques were employed for screening polyhydroxyalkanoate (PHA) producers isolated from the environment. Three degenerate primers were designed based on multiple sequence alignment results and were used as PCR primers to detect PHA synthase genes. Optimized colony PCR conditions were a…
Rigorous coupled-wave analysis (also called the Fourier-modal method) is an efficient tool for the numerical analysis of grating diffraction problems. We show that, with only a few modifications, this method can be used efficiently for the numerical analysis of aperiodic diffraction problems, including photonic crysta…
Recent studies on two aspects of silica glass as a photonic material will be described. Part A of this review will be focused on structural disorder and structural relaxations in silica glass. With regard to the structural disorder, investigations have been made to improve transparency and to shift the optical absorpt…
Abstract Polyamide 6 nanocomposites (PA6/NC) are novel type of composite materials comprising extremely thin, “nanometer scale” dispersions of smectitic silicate platelets. We prepared such PA6/NC materials via a melt compounding technique using suitably organomodified montmorillonite or hectorite type clays. The high…
The circular photogalvanic effect (CPGE) has been observed in (100)-oriented $p$-GaAs/AlGaAs quantum wells at normal incidence of far-infrared radiation. It is shown that monopolar optical spin orientation of free carriers causes an electric current which reverses its direction upon changing from left to right circula…
Deviations from randomicity in In(x)Ga(1-x) As semiconductor alloys induced by elastic effects are investigated within the Keating potential. Our model is based on Monte Carlo simulations on large (4096 atoms) supercells, performed with two types of boundary conditions: Fully periodic boundary conditions represent the…
The magnetic field dependence of the SDW transition in (TMTSF)$_2$ClO$_4$ for various anion cooling rates has been measured, with the field up to 27T parallel to the lowest conductivity direction $c^{\ast}$. For quenched (TMTSF)$_2$ClO$_4$, the SDW transition temperature $T_{\rm {SDW}}$ increases from 4.5K in zero fie…
The perturbation theory for calculation of the effective conductivity of the plane consisting of pieces of different conductivities is constructed and the convenient diagram technique for this perturbation theory is elaborated. It is shown that for the chessboard perturbative calculations give results which are in agr…
We introduce an anisotropic two-dimensional lattice gas model of metal terminated II-IV(001) seminconductor surfaces. Important properties of this class of materials are represented by effective NN and NNN interactions, which result in the competition of two vacancy structures on the surface. We demonstrate that the e…
The low field magnetotransport of ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ (LSMO) films grown on ${\mathrm{SrTiO}}_{3}$ substrates has been investigated. A high quality LSMO film exhibits anisotropic magnetoresistance (AMR) and a peak in the magnetoresistance close to the Curie temperature of LSMO. B…
The experimentally observed order-of-magnitude reduction in the thermal conductivity along the growth axis of (GaAs)n/(AlAs)n (or n×n) superlattices is investigated theoretically for (2×2), (3×3) and (6×6) structures using an accurate model of the lattice dynamics. The modification of the phonon dispersion relation du…
We compute time-dependent solutions of the sharp-interface model of dendritic solidification in two dimensions by using a level set method. The steady-state results are in agreement with solvability theory. Solutions obtained from the level set algorithm are compared with dendritic growth simulations performed using a…
▪ Abstract We review the recent progress in the study of layered magnetic manganites La 2−2x Sr 1+2x Mn 2 O 7 , which have many unique features of charge transport and magnetism inherent to the quasi-two-dimensional electronic structure. The system shows a wide variety of magnetic-field-induced phenomena due to the la…
Fermentation strategies for the production of poly(3-hydroxybutyrate) (PHB) from whey by recombinant Escherichia coli strain CGSC 4401 harboring the Alcaligenes latus polyhydroxyalkanoate (PHA) biosynthesis genes were developed. The pH-stat fed-batch cultures of E. coli CGSC 4401 harboring pJC4, a stable plasmid conta…
High-temperature superconductivity has a significant opportunity to improve the performance of nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) systems. The low rf losses and low operating temperatures of superconducting coils allow them to improve the signal-to-noise ratio in applica…
This micro-review presents an overview of molecular materials derived from phthalocyanines which are substituted with crown ether rings. These flat disk-like molecules can self-assemble into ordered, well-defined structures with or without the aid of alkali metal ions. Highly ordered assemblies of crown ether phthaloc…
We investigate atomic mechanisms of grain boundary (GB) diffusion by combining molecular dynamics (MD), molecular statics, the harmonic approximation to atomic vibrations, and kinetic Monte Carlo (KMC) simulations. The most important aspects of this approach are the basin-constrained implementation of MD and an automa…