Materials Literature
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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…
The occurrence of metastable or stable domain states on mesoscopic length scales seems to be a widespread property of many solids undergoing phase transitions in the presence of quenched random fields. A survey is given on the experimental evidence of domain states in various magnetic, ferroelectric and structural sys…
We investigate the effect on the thermoelectric figure of merit of preparing materials in the form of one-dimensional conductors or quantum wires. Our calculations show that this approach has the potential to achieve a significant increase in the figure of merit over both the bulk value and the calculated superlattice…
Silicon carbide (SiC) thin films were deposited on titanium carbide (TiC) substrates by pyrolysis of 1,3 disilacyclobutane (C2H8Si2), at atmospheric pressure, in an inverted-vertical cold-wall chemical vapor deposition reactor. The growth rate, morphology, and crystallinity of the films were studied, at constant C2H8S…
This review surveys the behaviour of graphite under loading conditions in which the stressing is on the whole tensile. The performance of a recently introduced model of graphite failure is reviewed in relation to the models from which it was developed, and against data obtained from a wide range of experiments on the…
A new noncontact calorimetric method has been developed based on inductive heating of a metallic spherical bulk sample by a power-modulated radio-frequency field under ultrahigh vacuum conditions. From the pyrometrically measured temperature response the specimen’s external (due to radiative heat loss) and internal re…
The initial permeability of soft polycrystalline ferrites exhibits thermal hysteresis when the temperature is cycled from above the Curie temperature T c to below. The temperature loops are classified into two categories according to the presence or absence of a secondary peak (SP), in addition to the Hopkinson peak,…
A model pair potential is calculated for Mn-Mn pairs in Al using a Green's function method. The pair potential has a preferred spacing of 4.7 \AA{}. The energy resulting from these Mn-Mn interactions strongly favors the ${\mathrm{Al}}_{6}$Mn, \ensuremath{\alpha}-AlMnSi, and icosahedral quasicrystal structures relative…