Materials Literature
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Amorphous hydrogenated silicon carbide (a-SiC:H) films were deposited from a mixture of silane and methane gases using the plasma-enhanced chemical vapor deposition (PECVD) process. The properties of the film, following ammonia plasma treatment, are reported. A lower silane flow rate reduces the refractive index, but…
Optical properties of single-walled boron nitride nanotubes have been studied theoretically. The dielectric functions calculated from the gradient approximation and the random-phase approximation are consistent with each other. The imaginary and the real parts of the dielectric function, respectively, exihibit the spe…
We have studied an oxidation effect of multiwalled carbon nanotubes (MWCNTs) grown by thermal chemical vapor deposition (CVD) using ultraviolet photoelectron spectroscopy (UPS) and transmission electron microscopy (TEM). With an increasing oxygen exposure, the carbon 2 p -π states at ∼3 eV below the Fermi level in the…
The analysis of the different amino acid sequences deduced from the complete genome sequence of the gram-positive bacterium Staphylococcus aureus suggested the presence of two eukaryotic-protein-like low-molecular-mass phosphotyrosine protein phosphatases, which are usually found in gram-negative bacteria. To check th…
Polycrystalline ZnO films both exhibiting strong ultraviolet (UV) photoluminescence (PL) and having smooth surfaces applicable to electronic devices have been obtained by rf-sputter deposition and subsequent heat treatment. The peak of UV PL was located at 3.05 eV and exhibited a linewidth as narrow as 70 meV, along w…
Anisotropic optical spectra coupled with antiferromagnetic spin ordering (SO) and orbital ordering (OO) have been investigated for single crystals of LaVO_{3} and YVO_{3}. The orbital-dependent Mott-Hubbard gap transitions are observed around 2 eV. The transitions composed of the two peaks show distinct anisotropy and…
A multiscale scheme combining molecular dynamics (MD) and microscopic phase-field theory is proposed to study the structural phase transformations in solids with inhomogeneous strain field. The approach calculates strain response based on MD and atomic diffusion based on the phase field theory. Simulations with the ne…
We study phase diagrams of the Hubbard model on anisotropic triangular lattices, which also represents a model for $\kappa$-type BEDT-TTF compounds. In contrast with mean-field predictions, path-integral renormalization group calculations show a universal presence of nonmagnetic insulator sandwitched by antiferromagne…
The ability of an arginine residue to function as the active site acid catalyst in the fumarate reductase family of enzymes is now well-established. Recently, a dual role for the arginine during fumarate reduction has been proposed [Mowat, C. G., Moysey, R., Miles, C. S., Leys, D., Doherty, M. K., Taylor, P., Walkinsh…
We report an improvement in oxidation resistance of single-walled carbon nanotubes (SWNTs) produced by arc discharge in a bowl-like cathode. The Raman spectrum of the new arc-discharge SWNTs shows a significant enhancement in the G/D (∼1590:∼1350 cm -1 ) ratio, suggesting that cleaner and less defective SWNTs are gene…
Two one-dimensional gallium fluorodiphosphates Ga(P 2 O 7 )F·H 3 N(CH 2 ) 3 NH 3 ·3H 2 O, 1, and Ga(P 2 O 7 )F·H 3 N(CH 2 ) 3 NH 3 ·H 2 O, 2, have been synthesized under mild conditions (<100 °C) from aqueous mixtures of Ga(NO 3 ) 3 ·6H 2 O, P 2 O 5, 1,3-diaminopropane, and HF. Their structures consist of anionic chai…
The photophysical and photochromic properties of 2,2-diphenyl-2H-naphtho[1,2-b]pyran and substituted derivatives were investigated by steady state and time-resolved optical absorption and emission spectroscopy in solution at room temperature and in a frozen matrix at 77 K. Fluorescence quantum yields, fluorescence lif…
Simple methods for preparing boron carbide nanowires have been investigated. The methods involve thermal evaporation of C/B/B 2 O 3 powder precursors in an argon atmosphere with or without metal catalysts. High-purity nanowires (50−200 nm) were obtained by employing a precursor that has C:B:B 2 O 3 molar ratios of 1:2…
Palladium-catalyzed polymerization of pseudo- p -divinyl[2.2]paracyclophane ( 2 ) and 2,5-dialkoxy-1,4-diiodobenzenes ( 3a and 3b ) was carried out to give the corresponding polymers ( 4a and 4b ) having [2.2]paracyclophane as a repeating unit. The structures of the polymers were supported by 1 H and 13 C NMR spectra.…
We successfully formed an inclusion complex between nylon-6 and α-cyclodextrin and attempted to use the formation and subsequent disassociation of the nylon-6/α-cyclodextrin inclusion complex to manipulate the polymorphic crystal structures, crystallinity, and orientation of nylon-6. Formation of the inclusion complex…
Two families of narrow polydispersity poly(styrene)-based block copolymers bearing side groups containing both a phenyl ring and a para -linked semifluorinated side group were designed to produce stable low energy surfaces. The effects of the phenyl ring on the surface and bulk structure of the materials were investig…
Magnetic properties of the Co valence tautomers are considered in wide range of magnetic field and temperature. Particularly, a model of the first order structural phase transition accompanied by a magnetic moment jump is proposed. The phase diagrams of the phase transition on a B-T plane (B is magnetic field and T is…
A transition for a random coil to an extended chain conformation in dilute polyaniline solutions has been shown to induce delocalization of polarons and to increase the conductivity in the solid state by MacDiarmid et al. We have investigated a similar chain extension during a transition from isotropic to a liquid cry…
Polymeric light-emitting diodes with sufficient brightnesses, sufficient efficiencies, sufficiently low driving voltages, and various interesting features have been reported. The relatively short device lifetime, however, still remains as a major problem to be solved before any commercial applications can be realized.…
Thin films were made by spinning a dispersion of tin-doped indium oxide particles, having an average diameter of 14 nm, onto glass substrates. As-deposited thin films displayed a resistivity ρ of 0.3 Ω m and some optical absorption. Annealing in vacuum at 200–400 o C for 2 h, and subsequently in air at 500 o C for 2 h…