Materials Literature
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We report dc transport and magnetization measurements of Jc in MgB2 wires fabricated by the powder-in-tube method, using commercial MgB2 powder with 5 %at Mg powder added as an additional source of magnesium, and stainless steel as sheath material. By appropriate heat treatments, we have been able to increase Jc by mo…
We describe an ab initio method for calculating the electronic structure, electronic transport, and forces acting on the atoms, for atomic scale systems connected to semi-infinite electrodes and with an applied voltage bias. Our method is based on the density functional theory (DFT) as implemented in the well tested S…
We have investigated the nonlinear microwave properties of electron-beam coevaporated YBaCuO films on MgO, using stripline resonators at 2.3 GHz and temperatures 1.7-80 K. The oxygen content of the films ranged from strongly underdoped to overdoped. Above 20 K, the nonlinear response of the resonators was dominated by…
Aqueous solutions of a methylcellulose, ranging from 0.30 to 2.49 wt %, were studied by means of micro differential scanning calorimetry (micro DSC) and rheology. The effects of polymer concentration on the thermodynamic properties of these solutions were examined through a heating process and a following cooling proc…
Arrays of graphitic carbon nanoclusters were obtained by pyrolysis of nanoscale phase-separated block copolymers of polyacrylonitrile and poly(n-butyl acrylate). Upon heating in an inert atmosphere to temperatures ranging from approximately 400 to 1200 degrees C, polyacrylonitrile domains were converted into carbon na…
Supported Au catalysts are very selective for the direct formation of hydrogen peroxide from H2/O2 mixtures at 2 degrees C; the rate of H2O2 synthesis is markedly increased if Au-Pd alloy nanoparticles are generated by the addition of Pd.
The electrical field arising around an inhomogeneous conductor when an electrical current passes through it is not screened, as distinct from 3D conductors, in low-dimensional conductors. As a result, the electrical field depends on the global distribution of the conductivity sigma(x) rather than on the local value of…
[reaction: see text] Helical polyacetylene fibers with absolutely symmetric structures were prepared by polymerization of acetylene using copper tartrate as a catalyst. There were always only two coiled polyacetylene fibers grown on a single copper nanocrystal. The two coiled fibers had absolutely opposite helical sen…
Abstract To investigate the role of the internal donor in a Ziegler–Natta catalyst, the nature and existing states of the internal donor were intentionally varied by alkylaluminium treatment before polymerization, and the catalytic properties during propene polymerization were accurately evaluated using the stopped‐fl…
A meso -tetraphenylporphyrin derivative with two butanethiol and two carboxylate groups on opposite phenyl substituents was first covalently bound to citrate gold particles by a self-assembly procedure. In a second self-assembly step the remaining areas on the gold surface were covered with a monolayer of a bolaamphip…
Abstract This work is focused on the analysis of the scale‐up process of styrene drying by adsorption onto activated alumina as a necessary step in the manufacture of styrene–butadiene rubber. In a previous work, the mathematical model was developed and the design parameters were estimated from the fitting of the mode…
We report on structural, magnetic, and electron spin resonance (ESR) investigations in the manganite system ${\mathrm{LaMn}}_{1\ensuremath{-}x}{\mathrm{Cr}}_{x}{\mathrm{O}}_{3}$ $(x<~0.5).$ Upon Cr-doping we observe a reduction of the Jahn-Teller distortion yielding less distorted orthorhombic structures. A transit…
Abstract For polyimide thin films, the dielectric properties were investigated with the capacitance and optical methods. The dielectric constants of the 4,4′‐oxydianiline (ODA)‐based polyimide thin films varied from 2.49 to 3.10 and were in the following decreasing order: 3,3′,4,4′‐biphenyltetracarboxylic dianhydride…
Nanoporous methyl silsesquioxane (MSSQ), which is an important and promising candidate for spin-on ultralow dielectric constant applications, has been produced via the thermosetting of MSSQ, templated by a nanodispersed, thermally decomposable pore generator (porogen)−poly(methyl methacrylate- co -dimethylaminoethyl m…
The acid−base properties of germanate glasses cannot presently be compared quantitatively with those of silicate, borate, and several other glasses because the optical basicity of the parent oxide, Λ(GeO 2 ), has not yet been unequivocally established. The usual method of measuring optical basicity, relying on probe i…
Selective catalytic reduction of NO with NH3 over high weight percentage CeO2-zeolites showed excellent NOx conversions at very high space velocities under simulated exhaust gas conditions in the presence of H2O.
A high-pressure phase of $\mathrm{T}\mathrm{i}{\mathrm{O}}_{\mathrm{2}}$ with an $\ensuremath{\alpha}\mathrm{\text{\ensuremath{-}}}\mathrm{P}\mathrm{b}{\mathrm{O}}_{\mathrm{2}}$-type structure has been synthesized via very energetic Nd-YAG laser pulse irradiation of oxygen-purged Ti target. The nanometer-size $\ensure…
Quantitative studies of the correlation between sonochemical activity and acoustical noise spectra have been performed. The width of the second harmonic (fwhm2) of the acoustical signal in the frequency domain shows a sensitive dependence to the presence of small amounts (mM range) of an anionic surfactant in water. T…
A Monte Carlo simulation method has been used to calculate the reflection electron energy loss spectrum for Ag. The differential inelastic cross-section is obtained from an inhomogeneous electron self-energy in the surface region. A comparison of the calculation result with an experiment shows a remarkable agreement o…
The present work represents a continuation of part I of this series of papers, in which we investigated the phenol yields in the OH-initiated oxidation of benzene under conditions of low to moderate concentrations of NOx, to elevated NOx levels. The products of the OH-initiated oxidation of benzene in 700–760 Torr of…