Materials Literature
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The second-electron affinity of the oxygen atom is often required in modelling the behaviour of ceramics. It is usually taken to be about 8 eV, independent of the structure of the oxide being modelled. We show that this is not so. Quantum-mechanical calculations show that the true second-electron affinity of an in-cry…
Abstract New phosphorylated epoxy‐imide polymer was obtained using diimide‐diepoxide (DIDE) cured with bis(3‐aminophenyl)methylphosphine oxide (BAMP). In addition, composition of the synthesized diimide‐diepoxide (DIDE) with common curing agents, e.g., 4,4′‐diaminodiphenylether (DDE) and 4,4′‐diaminodiphenylsulfone (D…
Metallocene/aluminoxane catalysts are among the most important recent discoveries in the field of catalytic polymerization of olefins. Not only their high activities, but also the fact that they permit the synthesis of polymers with superior blends of properties are remarkable both from academic and industrial points…
RATIONALE AND OBJECTIVES: Gd-DTPA is a well-characterized, safe contrast agent frequently used in magnetic resonance imaging (MRI) of the central nervous system. The purpose of this double-blind, comparative MRI study of brain, spine, trunk, and limbs was to evaluate the safety and efficacy of Gd-DOTA versus Gd-DTPA i…
We have observed strong photoluminescence (PL) from a well-defined two-dimensional (2D) Si structure formed on a SIMOX (separation by implanted oxygen) wafer, where the thin ( <5 nm) single crystalline silicon film is sandwiched between SiO 2 layers. The PL intensity has a sharp maximum at a Si thickness of about 2…
Quality factors and fluence-to-ambient and fluence-to-personal-dose equivalent conversion factors for neutrons have been recalculated for neutrons with energies ranging from thermal to 20 MeV. The new calculations are based on the recommendations given in ICRU Publication 60 for the quality factor and on stopping powe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTrisubstituted Heteropolytungstates as Soluble Metal-Oxide Analogs. Isolation and Characterization of [(C5Me5)Rh.cntdot.P2W15Nb3O62]7- and [(C6H6)Ru.cntdot.P2W15Nb3O62]7-, Including the First Crystal Structure of a Dawson-Type Polyoxoanion-Supported Organometallic ComplexMat…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural Diversity in Solvated Lanthanide Halide ComplexesWilliam J. Evans, Julie L. Shreeve, Joseph W. Ziller, and Robert J. DoedensCite this: Inorg. Chem. 1995, 34, 3, 576–585Publication Date (Print):February 1, 1995Publication History Published online1 May 2002Published…
<div class="htmlview paragraph">In the Dual Equal variable camshaft timing strategy, the intake and exhaust events are equally phase-shifted relative to the crankshaft as a function of engine operating conditions. The primary emphasis is on improved fuel economy and emissions at part load. The external EGR syste…
A differential scanning calorimeter with a temperature range of 77 to 873 K has been developed for use in combination with either time-resolved X-ray scattering or high-resolution energy-dispersive powder diffraction studies using synchrotron radiation. The first results of successful experiments are briefly described.
The synthesis of chiral liquid crystalline diacrylates is described. By mixing one of them with non-chiral liquid crystalline diacrylates. cholesteric phases are obtained of which the wavelength of reflection can be chosen by the composition of the mixture. After isothermal photopolymerization of the mixture a crossli…
D/H exchange between methane and a zeolite is the simplest reaction between a zeolitic proton and a hydrocarbon. Because of its simplicity, it offers a unique opportunity to test out possibilities that are offered by present-day computational techniques to obtain theoretical insight into the catalytic action of zeolit…
A computer experiment on foam rheology is performed with a simplified model in which the viscous dissipation in the liquid phase is taken into account. The simulation is carried out under the sheared boundary condition with a small shear rate. It is observed that violent flow like that of an avalanche occurs intermitt…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnomalous mixing behavior of polyisobutylene with other polyolefinsR. Krishnamoorti, W. W. Graessley, L. J. Fetters, R. T. Garner, and D. J. LohseCite this: Macromolecules 1995, 28, 4, 1252–1259Publication Date (Print):February 1, 1995Publication History Published online1 Ma…
An appearance of an easy orientation axis of a nematic liquid crystal on the isotropic aligning surface under the light absorption by in-bulk azo dye molecules is observed. It is shown that orientation of LC molecules in the irradiated region is close to the direction of the exciting beam polarization. Accompanying to…
1 An Introduction to Clay Minerals and Isotope Geochemistry.- 1 Fundamentals of Clay Mineralogy.- 1.1 Definition.- 1.2 Basic Structural Units and Layer Types.- 1.3 Classification of Clay Minerals.- 1.4 Thermodynamic Considerations for Clay Minerals.- 1.5 Clay Separation and Characterization.- 2 Principles of Isotope G…
Model oxide-supported metal catalysts have been prepared by evaporating a metal (e.g., Cu, Pd) onto an oxide ( SiO 2 , Al 2 O 3 ) thin film (~100 Å) which, in turn, is supported on a refractory metal (Mo, W, Ta) surface. The deposited metal films, upon annealing, form small metallic clusters on the oxide surface whose…
The sol–gel process represents a room‐temperature method of producing a wide range of ceramic materials through the formation of a glassy network by the polymerization of suitable monomers. The use of the technique to produce, for example, sonogels, organic‐inorganic composites, NLO glasses, and electrooptical materia…
Abstract It was observed that surface-enhanced Raman scattering (SERS) spectra of p-nitrothiophenol (PNTP) self-assembled monolayer adsorbed on a smooth silver electrode changed by laser light irradiation. The SERS spectra were identical with those of p-aminothiophenol (PATP). This reaction proceeded even at the elect…
The shape memory effect has been observed in several material systems: metals, ceramics and polymers. Mainly metallic systems in which a strain-induced or thermallyinduced martensitic transformation occurs, have been explored. Also, recent discoveries have shown that shape memory effects in specific systems can also b…