Materials Literature
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A program to develop a metal hydride based hydrogen isotope separation process began at the Savannah River Laboratory in 1980. This semi-continuous gas chromatographic separation process will be used in new tritium facilities at the Savannah River Site. A tritium production unit is scheduled to start operation in 1992…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT[.beta.-Na2Fe18S30]8- and [Na9Fe20Se38]9-: high-nuclearity clusters by mono- or bicyclization of unidimensional polymeric fragments and the existence of isomeric monocyclic clustersJing Feng You, G. C. Papaefthymiou, and R. H. HolmCite this: J. Am. Chem. Soc. 1992, 114, 7, 2…
The frequency spectra of the linear and third nonlinear permittivities, ε 1 * and ε 3 * , have been measured for polyvinyl acetate (PVAc) at temperatures above T g . The Debye relaxation of ε 1 * associated with the micro-Brownian motion of noncrystalline segments is found to be accompanied by the complex frequency de…
Abstract Nonlinear optical (NLO) materials provide the basis for an array of active optical devices under development throughout several high technology industries. Applications would include communications, data storage, and computing. Active optical devices can be used to alter light in order to encode or direct inf…
Abstract The role of polar additives, o, m, and p‐dinitrobenzene, on hole transport in 1,1‐bis(di‐4‐tolylamino‐phenyl)cyclohexane doped polycarbonate is investigated. The results are described by a model based on hopping through a manifold of states with superimposed energetic and positional disorder that remains stat…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganometallic nonlinear optical (NLO) polymers. 1. Pendant ferrocene NLO-phores in a poly(methyl methacrylate) copolymer. The first η(2) organometallic NLO polymerMichael E. Wright, Edward G. Toplikar, Robert F. Kubin, and Michael D. SeltzerCite this: Macromolecules 1992, 2…
Cyclophane 1 with four donor units (two tetra-thiafulvalene (TTF) and two hydroquinone units) can be prepared by anodic oxidation of a strained cyclic “monomer” containing both of these donor components. Although in the solid state the TTF units in 1 are bent towards the cavity, making it too small for guest molecules…
Abstract New stability constant data are presented for the minerals blixite, mendipite and the compound Pb 7 O 6 Cl 2 .2H 2 O at 298.2 K and P = 10 5 Pa. Mendipite is in fact a metastable phase at this temperature, being thermodynamically stable under the appropriate conditions at temperatures above about 29°C Kinetic…
Single crystals of the quasi-one-dimensional conductor (perylene)Co-bis(maleonitriledithiolate)(CH2Cl2)0.5 were prepared by electrocrystallization. The structure at room temperature is incommensurate with modulation wave vector (0.22a*, -0.13b*, -0.36c*). At T = 295 K it crystallizes in space group P1BAR with Z = 2 an…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBond-stretch isomerism in the chlorooxomolybdenum complexes cis-mer-MoOCl2(PR3)3: a reinvestigationKeum Yoon, Gerard Parkin, and Arnold L. RheingoldCite this: J. Am. Chem. Soc. 1992, 114, 6, 2210–2218Publication Date (Print):March 1, 1992Publication History Published online1…
Morphol., lamellar thickening, and the transition between the crystal and the hexagonal columnar phase were studied in 1,4-trans-polybutadiene (I) by optical and electron microscopy, time-resolved synchrotron x-ray diffraction, and DSC. I could form several-thousand-.ANG.-thick lamellas of the extended or nearly exten…
Abstract Shale samples ranging in depth from 305 m to 3658 m (Miocene to Late Cretaceous) from a single well in DeWitt County, Texas were examined by x-ray diffraction (XRD), scanning-transmission electron microscopy (STEM), and analytical electron microscopy (AEM) techniques to detail the mineralogical, textural, and…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation and characterization of an A1u (Oxo) iron(IV) porphyrin .pi.-cation-radical complexHiroshi Fujii and Kazuhiko IchikawaCite this: Inorg. Chem. 1992, 31, 6, 1110–1112Publication Date (Print):March 1, 1992Publication History Published online1 May 2002Published iniss…
Abstract Thermal characterization was carried out on highly stereoregular and regioregular syndiotactic polypropene (sPP) obtained with isopropylidene(cyclopentadienyl)(9‐fluorenyl)zirconium dichloride and methylaluminoxane. The influence of molecular weight and syndiotacticity degree on the thermodynamic melting poin…
The mechanism by which cAMP-dependent protein kinase-catalyzed phosphorylation modulates the activities of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase was examined after site-specific mutation of the cAMP-dependent phosphorylation site (Ser32) to aspartic acid or alanine. The mutant and wild-type enzymes were…
Abstract Conventional batch adsorption‐isotherm experiments are conducted under conditions that are generally not representative of field conditions. Our objective was to develop and illustrate a technique that uses continuous, unsaturated flow through intact soil cores and gives information analogous to standard batc…
Abstract Both Lewis and Brönsted acid sites were found on the surface of TiO2–SiO2 mixed oxide, thouth no Brönsted acid sites were detected on the surface of pure TiO2 and SiO2. While on the surface of TiO2–Al2O3 mixed oxide, no Brönsted acid sites were generated. The rate of isomerization of 1-butene was found to be…
The results of Anthony et al. [Phys. Rev. B 42, 1104 (1990)] on the thermal conductivity at 25 \ifmmode^\circ\else\textdegree\fi{}C of diamonds grown with a reduced $^{13}\mathrm{C}$ concentration are analyzed. The effect of reducing the $^{13}\mathrm{C}$ concentration is about ten times greater than these authors exp…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface chemistry of colloidal silver: reduction of adsorbed cadmium(2+) ions and accompanying optical effectsArnim Henglein, Paul Mulvaney, Thomas Linnert, and Arnold HolzwarthCite this: J. Phys. Chem. 1992, 96, 6, 2411–2414Publication Date (Print):March 1, 1992Publication…
We have prepared Si1−yCy alloy layers on Si (001) substrates using solid-source molecular-beam epitaxy. The lattice mismatch between diamond and Si is about 50%. Thus, a Si1−yCy (y=0.02) alloy has a mismatch of about 1% with respect to Si assuming Vegard’s law. Transmission electron microscopy (TEM) shows the layers t…