Materials Literature
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Auger electron spectroscopy has been used to measure the diffusion of oxygen away from the surface of single-crystal zirconium (0001). The experimental data have been modeled by an infinitely thin oxygen layer (ITOL) and thicker layers. The ITOL model best describes the diffusion behavior under the experimental condit…
The temperature dependence of the Al 2p line width and binding energy has been studied in the range from 80 K up to and beyond the Al bulk melting point (${\mathit{T}}_{\mathit{m}}$=933.5 K). By comparing the experimental data with results from calculations based on a nearest-neighbor force constant model, we find the…
The bond charge model (BCM), originally designed by Weber for the dynamics of tetrahedrally coordinated semiconductors, is shown to be applicable, with minor adjustments, to ${\mathit{sp}}^{2}$ configurations. Calculations for the bulk and surface dynamics of graphite, based on a comparatively small number of adjustab…
Abstract Diffusion coefficient and solubility of Irganox 1076 antioxidant in different ethylene polymers (LDPE, LDPE/LLDPE blend, and EVA) were studied between 45 and 80°C. For correct evaluation of the results, physical characteristics of the polymers and the additive were determined as a function of temperature. Goo…
Abstract The photooxidation of poly(vinyl chloride) involves complex reactions in which photooxidation and photodiscoloration by the formation of polyenes compete. These reactions are now fairly well understood, and on the basis of the mechanisms formerly reported, it appears possible to investigate the influence of i…
We have carried out stochastic dynamics and molecular dynamics simulations of n-tridecane (C13H28) as isolated chains, in bulk melts, and in confined melts between solid surfaces, employing both a united atom (UA) model and an explicit atom (EA) model, in order to compare chain conformations, packing, orientational co…
The possible technological importance of rare-earth-doped semiconductors has led to great interest in these materials. However, little at the atomic level is hitherto known about such defects in the host lattice. Using first-principles calculations, the nature of erbium point defects in crystalline silicon is investig…
The angular dependences of grazing-incidence x-ray scattering and Ge K\ensuremath{\alpha} fluorescence yield were measured for ${\mathrm{Si}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ge}}_{\mathit{x}}$/Si and its inverted Si/${\mathrm{Si}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ge}}_{\mathit{x}}$ heteros…
Explicit study of the hydrogen bond network in water offers a microscopic approach to understanding the anomalous properties of water, while an alternate, thermodynamic approach is offered by the reentrant limit of stability (spinodal) conjecture. To relate the two approaches, we develop a lattice model based on micro…
The AraC protein, which regulates the L-arabinose operons in Escherichia coli, was dissected into two domains that function in chimeric proteins. One provides a dimerization capability and binds the ligand arabinose, and the other provides a site-specific DNA-binding capability and activates transcription. In vivo and…
The frequency and temperature dependence of the real and imaginary parts of the ac conductivity of the tellurium cuprate glassy semiconductors are reported in the frequency range ${10}^{2}$--${10}^{5}$ Hz and in the temperature range 80--350 K. The experimental data have been analyzed with reference to various theoret…
In this paper, the differential effects brought about by the MgO, CaO, and SrO family of hosts on the topology of the energy surface corresponding to the ground state of the clusters (CuO6)10− and (AgO6)10− along the a1g and eg,θ vibrational modes, are studied by means of the ab initio embedding model potential method…
In this article we present a study of a new class of optical fibers based on lead germanate glass. The maximum vibrational frequency of this glass is intermediate between silica and zirconium barium lanthanum aluminum fluoride glass, causing a beneficial change in nonradiative decay and therefore quantum efficiency fo…
Anomalous giant lattices have been observed on four separate samples of highly oriented pyrolytic graphite with scanning tunneling microscopy. They exhibit hexagonal symmetry with lattice constants of 1.7, 2.8, 3.8, and 6.6 nm. Atomic resolution of graphite was obtained simultaneously. Kuwabara, Clarke, and Smith [App…
The symmetry operations for a general chiral carbon nanotubule are identified and the relevant symmetry groups are constructed. The consequences of these symmetry properties are briefly discussed with regard to the electronic and lattice properties of the nanotubules.
We study the electronic structure of ${\mathrm{La}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Sr}}_{\mathit{x}}$${\mathrm{MnO}}_{3+\mathrm{\ensuremath{\delta}}}$, x=0, 0.1, 0.2, 0.3, and 0.4, across the semiconductor-metal transition, using various electron spectroscopy techniques. The negligible intensity seen a…
We discuss the formation of gold metal colloids in a variety of surfactant/solvent systems. Static and dynamic light scattering, small angle x-ray and neutron scattering, TEM analysis, and UV-visible absorbance are used to characterize the kinetics of formation and final colloid stability. These gold colloids exhibit…
The structure and the electronic properties of graphite monofluoride (CF${)}_{\mathit{n}}$ have been studied within the framework of the density-functional technique, using nonlocal ionic pseudopotentials and a large number of plane waves. The chair conformation is shown to be energetically favored with respect to the…
The Ωt intensity parameters (t=2,4,6) of Er3+ ions in several oxide glasses and the isomer shift (IS) of 151Eu Mössbauer spectra in glasses of the same composition were determined. Among these Ωt’s, the Ω6 parameter was found to have a good relation with IS; Ω6 decreases with an increase of IS which reflects the 6s el…
We present soft-x-ray-absorption spectra (XAS) of ${\mathrm{LaCoO}}_{3}$ taken at different temperatures (80--630 K). The shape of the multiplets in the Co 2p XAS spectra conveys information on the symmetry and spin of the ground state. The O 1s XAS spectra are related to unoccupied metal bands through covalent mixing…