Materials Literature
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Electronic, vibrational and rotational contributions to the dipole moment μ, polarizability α, and first and second hyperpolarizabilities, β and γ, are presented for the boron hydride molecule; static and dynamic rovibrational properties are reported for the first time. The electronic contributions are computed ab ini…
Alternate feeding of glucose and propionic acid to phosphate-depleted batch cultures of Ralstonia eutropha (reclassified from Alcaligenes eutrophus ) produced poly(3-hydroxybutryate- co -3-hydroxyvalerate) [P(3HB- co -3HV)] with thermal properties markedly different from random copolymers of similar monomer content. T…
Discontinuous molecular dynamics simulations are used to study the structure and relaxation of large, off-lattice, near-perfect, tri- and tetrafunctional polymer networks at a packing fraction of 0.43. The networks are constructed by end-linking freely jointed, tangent hard-sphere chains ranging in length from N = 20…
A new route for the synthesis of conducting polypyrrole–silica composites is described. Silica gel particles were modified by aminopropyltriethoxysilane (APS) and acted as porous inorganic substrates for the in situ synthesis of polypyrrole (PPy). The resulting polypyrrole–silica–APS hybrid materials were characterize…
The state of Bi at the grain boundaries of ZnO varistors was analyzed using FE‐TEM with EDS point and mapping analysis with a spatial resolution of less than 1 nm. The continuous existence of Bi of less than 1/2 atomic layer has been confirmed at ZnO‐ZnO junctions without any secondary phase. The coexistence of a crys…
Changes in the structure and stoichiometry of the p-CdTe surface as a result of etching have been studied by high-resolution x-ray photoelectron spectroscopy and the Rutherford backscattering method. Etching with bromine-methanol and bromine-butanol solutions is shown to enrich the surface with elementary tellurium .…
Biochemical controls that regulate the biosynthesis of poly-3-hydroxybutyrate (PHB) were investigated in Rhizobium (Cicer) sp. strain CC 1192. This species is of interest for studying PHB synthesis because the polymer accumulates to a large extent in free-living cells but not in bacteroids during nitrogen-fixing symbi…
The time-dependent quasi-one-dimensional transport of electrons or holes along the molecular columns in columnar liquid crystals has been studied. Recent mobility measurements on the tryphenylene-based HAT-n materials have revealed Gaussian transits in the liquid crystalline phases but dispersion in the crystalline ph…
The chemical reactions occurring in the thermal treatment of bisphenol-A polycarbonate (PC) and poly(methyl methacrylate) (PMMA) blends have been investigated by nuclear magnetic resonance (NMR), mass spectrometry (MS), size exclusion chromatography (SEC), and thermogravimetry (TG). Our results suggest that in the mel…
To investigate responses to longitudinal torsion and the effect of temperature on the torsional stiffness of superelastic nickel titanium archwires, eight batches of rectangular wires were tested at 18, 27, 37, and 40 degrees C ambient temperature. The wires were twisted 25 degrees and studied in deactivation. The res…
We have measured multicomponent chemical diffusion coefficients in a melt near to the low pressure water-saturated eutectic granite composition in the system K 2 O-Na 2 O-Al 2 O 3 -SiO 2 -H 2 O at 1.0 GPa and temperatures of 1300 and 1600 ℃. The measured diffusion profiles can be accounted for within the analytical er…
In Saccharomyces cerevisiae, the cytosolic and promitochondrial isoenzymes of fumarate reductase are encoded by the FRDS and OSM1 genes, respectively. The product of the OSM1 gene is reported to be required for growth in hypertonic medium. Simultaneous disruption of the FRDS and OSM1 genes resulted in the inability of…
Meso, meso′-buta-1,3-diyne-bridged Ni (II) octaethylporphyrin dimer thin films have been deposited by the Langmuir–Blodgett method and, for the first time, have been considered as the active layer in resistive gas sensors. In particular, the electrical conductivities of these films undergo a remarkable variation due t…
▪ Abstract Doped manganite perovskites exhibit large magnetoresistance, but usually only in high fields (>1 Tesla). Efforts are under way to understand the underlying mechanism and to explore possibilities of achieving large magnetoresistance at low fields, which has led to focused studies of spin-dependent transpo…
Macropore formation during anodization of highly resistive p‐type crystalline silicon in HF is reported for the first time. This formation is due to an instability of the dissolution attributed to the high resistivity of the silicon electrode as compared to that of the electrolyte, as it had been observed during anodi…
Abstract The density of proteins is an important quantity. For ab initio phasing in X-ray crystallography, such as low resolution envelope techniques [1, 2], an accurate protein density is essential to get a correct prediction of the protein volume from the amino acid sequence. An accurate value will also facilitate t…
The stress rupture characteristics of an enhanced Nicalon/SiC composite at 900°C have been examined. This temperature has been identified as being in the regime wherein oxidation embrittlement is operative. The enhancement of the composite involves the use of a coating around the fiber tows, comprising a C‐rich matrix…
The interrelation of degree and type of cross-linking and viscoelastic properties of sulfur-cured natural rubber (NR) vulcanizates was investigated by altering accelerator concentration, cure time, and cure temperature. Constants C 1 and C 2 from the Mooney-Rivlin equation were given via stress-strain measurement to e…
Bulk ${\mathrm{Al}}_{x}{\mathrm{As}}_{40}{\mathrm{Te}}_{60\ensuremath{-}x}$ and ${\mathrm{Al}}_{x}{\mathrm{As}}_{40\ensuremath{-}x}{\mathrm{Te}}_{60}$ glasses $(5<~x<~20)$ are found to exhibit memory and threshold switching. ${}^{27}\mathrm{Al}$ solid-state NMR measurements reveal that in both series of glasses,…
The dielectric properties of liquid crystal materials containing ionic impurities are analyzed in terms of space charge polarization. The theoretical expressions of the dielectric constant and the dielectric loss factor are derived by solving a diffusion equation for mobile ions under an AC field. Numerical calculatio…