Materials Literature
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The erosion of carbon by intensive hydrogen bombardment has been recently shown to decrease sharply at very high fluxes $(\ensuremath{\sim}{10}^{19}\mathrm{ions}/{\mathrm{cm}}^{2}\mathrm{s}).$ This effect cannot be explained by standard sputtering or erosion models, yet understanding it is central for selection of fus…
Genes involved in allose utilization of Escherichia coli K-12 are organized in at least two operons, alsRBACE and alsI, located next to each other on the chromosome but divergently transcribed. Mutants defective in alsI (allose 6-phosphate isomerase gene) and alsE (allulose 6-phosphate epimerase gene) were Als(-). Tra…
Color-center formation in F-doped, OH-free synthetic SiO(2) glasses by irradiation with F(2) excimer lasers (157 nm) was examined as a function of the F content. The concentration of photoinduced E(') centers was reduced to approximately 1/20 by 1 mol.% F(2) doping and remained almost constant on further doping to 7.3…
A theoretical investigation of the recently observed enhanced thermoelectric power S in (111)-oriented n-type $\mathrm{PbTe}/{\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Eu}}_{x}\mathrm{Te}$ multiple-quantum-wells $(x\ensuremath{\simeq}0.09)$ has been carried out, including both longitudinal acoustic phonon deformation po…
Deformation behavior of the segmented block copolymers was studied with synchrotron small-angle X-ray scattering (SAXS) and Fourier transform infrared spectroscopy (FTIR) methods. Polyurethanes used in this work consist of 4,4′-methylene-bis(phenyl isocyanate) and butanediol as a hard segment, and poly(tetramethylene…
Raman study of very thin (⩽3.5 nm) Si layers constituting Si/SiO2 superlattices and grown by molecular beam epitaxy is described. The Raman spectra show systematic dependence on thickness of the Si layers, which highlights the variety of disordered microstructures in the Si/SiO2 superlattices. A clear change in the vi…
Nanostructured PrCo5-based PrxCo100−x (x=15.4–20.5) powders have been synthesized by mechanical milling and subsequent annealing cast alloys. The best overall properties have been developed in stoichiometric PrCo5 powders milled for 4 h and annealed at 800 °C for 1 min with a high coercivity of 16.3 kOe along with a h…
Thermal degradations of 4,4′-diphenylmethane diisocyanate-based thermoplastic polyurethane elastomers were conducted and investigated as functions of heating conditions by using thermogravimetric analysis, ultraviolet-visible (UV-vis) spectroscopy, gel permeation chromatography (GPC), and Fourier transform infrared (F…
Experimental and theoretical polarized V K-edge spectra of ${\mathrm{V}}_{2}{\mathrm{O}}_{5}$ are presented. By analyzing experimental spectra, we find that quadrupole transitions are significant, although not dominant at the pre-edge region. Real-space multiple-scattering calculation, relying on a non-self-consistent…
Excellent deoxygenation of ketones and aldehydes is achieved with Keggin-type polyoxometalates in the presence of hydrogen (see Equation (1) for an example). The mixed addenda phosphovanadomolybdate [PV(2)Mo(10)O(4)](5-) was found to be the best catalyst. X-ray diffraction and IR studies suggest that the polyoxometala…
A phenomenological thermodynamic model has been developed to account for the effects of the film thickness on various properties of ferroelectric thin films. To this end, we have suitably incorporated a position-dependent stress distribution function into the elastic Gibbs function. Various physical properties can be…
The dynamics and the reversibility conditions of crystalline↔amorphous transitions induced in thin Ge0.07Sb0.93 films upon picosecond laser pulse melting were studied by real-time reflectivity measurements with nanosecond and picosecond resolution. The full transformation time could be resolved in a single exposure ex…
Vibrationally resolved 355 and 266 nm anion photoelectron spectra of B2N are presented. Photodetachment to two electronic states of linear B–N–B is observed and, aided by electronic structure calculations, assigned to the X̃ 1Σg+→X̃ 2Σu++e− and X̃ 1Σg+→Ã 2Σg++e− transitions. The electron affinity of B2N is 3.098±0.005…
In magnetoresistance measurements of a single multiwall carbon nanotube we have observed the periodic oscillation which increases in amplitude below 30 K. The period has the angular dependence of $1/\mathrm{cos}\ensuremath{\theta},$ $\ensuremath{\theta}$ being the angle between the nanotube axis and magnetic field, an…
The metal-insulator transition in manganites is strongly influenced by the concentration of holes present in the system. Based upon an orbitally degenerate Mott-Hubbard model, we analyze two possible localization scenarios to account for this doping dependence: First, we rule out that the transition is initiated by a…
Ab initio configuration interaction (CI) calculations are performed to study the ground state of small neutral and singly charged silver bromide clusters AgnBrp(±) (n,p⩽2). The results are obtained at complete active space self-consistent field and also at variational plus second order perturbational multireference CI…
A microscopic theoretical model is proposed for calculating the characteristics of ultraviolet photoemission and x-ray secondary electron emission induced from CsI photoconverters. This approach is based on a realistic picture of the basic interactions of photons and induced electrons within the material. Both differe…
Surface photovoltage spectroscopy (SPS) is introduced as a powerful tool for band gap determination of semiconductor powders. The main advantage of SPS is that scattering and reflection do not interfere with the spectra. Therefore, it does not suffer from the inherent limitations of transmission/reflection based spect…
Surface morphology characteristics and electron emission properties of boron-doped polycrystalline diamond thin films grown by microwave plasma-assisted chemical-vapor deposition were investigated using an ultra-high-vacuum scanning tunneling microscope. Small secondary grains with average size less than 10 nm were ob…
Poly(ethylene oxide) (PEO) chains were grafted onto a spherical thermally sensitive poly( $N$-isopropylacrylamide) microgel with a low critical solution temperature of $\ensuremath{\sim}32\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$. The shrinking of the microgel at higher temperatures led to a dramatic decrease in…