Materials Literature
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Cathodoluminescence (CL) and photoluminescence (PL) of nickel oxide (NiO) have been investigated. The observed emission bands in the visible and near infrared spectral ranges are attributed to Ni2+ intraionic transitions. Some of the features observed in the CL spectra recorded from vacuum annealed samples are tentati…
The physical properties of a series of organic superconductors with fourfold quasistacking structures, $\ensuremath{\lambda}\ensuremath{-}{\mathrm{BETS}}_{2}\mathrm{Ga}{X}_{z}{Y}_{4\ensuremath{-}z}$ [BETS=bis(ethylenedithiotetraselenafulvalene; $X,Y=\mathrm{F},$ Cl, Br; $0<z<2)]$ are changed continuously by tuni…
Monolithic mullite with low sintering shrinkage was synthesized from polymer/filler blendsMthat is, siloxane/alumina (siloxane/Al 2 O 3 ) (and siloxane/aluminum (siloxane/Al)) mixtures. The synthesis was based on a reaction‐bonding process of amorphous silica, which formed when the siloxane was oxidized, with Al 2 O 3…
Fatigue of copper single crystals, oriented for single slip, has been studied using electron channelling contrast imaging (ECCI) in a scanning electron microscope. This technique was used to detect and characterize dislocation structures in bulk specimens. With the incident beam set at the Bragg condition, changes in…
A series of polyesters, which are comprised of aromatic main chain backbones and flexible aliphatic side chains with 4-cyanobiphenyl end groups, has been synthesized based on a polycondensation of 2,2‘-bis(trifluoromethyl)-4,4‘-biphenyldiyldicarbonyl chloride with 2,2‘-bis{ω-[(4-(4-cyanophenyl)phenoxy]- n -alkoxy)carb…
The trapping of hydrogen atoms generated by γ-irradiation of different compounds containing the cube-shaped Si 8 O 12 -cage was investigated by means of electron spin resonance (ESR). The trapped hydrogen atoms were found to originate from the organic substituents of the cages. It was shown that intermolecular process…
Reaction between [Ru(py-pzH)3](ClO4)2 (where py-pzH = 3-(pyridin-2-yl)pyrazole) and Cu(II) or Cu(I) in methanol, in the presence of excess NEt3, affords the triple-strand helical supramolecular {[Ru(py-pz)3]2Cu3}(ClO4). The X-ray crystal structure and 1H NMR and electronic spectroscopic properties of {[Ru(py-pz)3]2Cu3…
Quasielastic neutron scattering experiments and molecular dynamics (MD) simulations have been used to investigate molecular diffusive motion near the melting transition of monolayers of flexible rod-shaped molecules. The experiments were conducted on butane and hexane monolayers adsorbed on an exfoliated graphite subs…
Abstract Equilibrium, diffusion, and fixed‐bed adsorption of n‐hexane in pellets of 5A zeolite (Rhone‐Poulenc) were studied between 373 and 573 K and at partial pressures up to 0.2 bar. Equilibrium data were obtained in a flow microbalance system. Diffusivity was studied simultaneously by gravimetric and ZLC technique…
Cathode rays, accelerated by tens of thousands of volts or more, have had immense scientific and technological value in the hundred years since Joseph John Thomson used them to discover the electron. The most familiar use of these electron beams is in cathode-ray tubes—as used in television sets and computer displays,…
The new d 10 −d 10 dimer Cu 2 (dppm) 2 (O 2 CCH 3 ) + (as a BF 4 - salt) has been prepared and characterized by X-ray crystallography and by 1 H and 31 P NMR, vibrational, and electronic spectroscopy. The compound is luminescent at 77 K but not at room temperature. MO calculations and geometry optimizations have been…
Solid-state postpolymerization of l -lactide was studied by two different ways with 0.1 mol % of stannous 2-ethyl hexanoate as the catalyst. In a two-step method, the ordinary melt polymerization of l -lactide was first performed at temperatures higher than the crystallization temperature ( T c ) of poly( l -lactide)…
The electrical properties of polymers filled with different types of conducting particles are reviewed. Following a theoretical description of a general effective media (GEM) equation, the experimental conductivity–volume fraction data for thermoplastic filled with vanadium oxide particles as well as thermosetting pol…
The tetragonal‐to‐cubic structural phase transition in pollucite (CsAlSi 2 O 6 ) was investigated using low‐temperature X‐ray powder diffraction in the temperature range of 93 to 298 K, and the lattice constants were refined with Rietveld analysis. It was found that CsAlSi 2 O 6 had a tetragonal phase with a space gro…
La croissance et le developpement des couches protectrices d'alumine sur des alliages NiAl et FeCrAl au cours de l'oxydation a 900°C et a 1300°C sont complexes du fait de la transformation de l'alumine metastable―y-Al 2 O 3 et―θ-Al 2 O 3 , en une phase,―α, plus stable. Comme les vitesses de transformation augmentent a…
It is well known that the spectral transmittance and reflectance of a thin film can be influenced by even small inhomogeneities or variations in its complex refractive-index profile. Formulas are derived that describe the theoretical variation of the spectral characteristics for small changes in the refractive index a…
Saturated hydrocarbon polymers may be differentiated by the relative amount and placement of methylene, methyl, methine, and quaternary carbon moieties. While it has been known or suspected for some time that polyolefins of conventional molecular weight (Mw ≈ 100 kg/mol) with dissimilar chemical microstructures are mo…
The synthesis and reactivity of ansa -metallocenes based upon the new ligand system R(Me)SiCp‘‘ 2 2 - (Cp‘‘ = C 5 Me 4 and R = (CH 2 ) n OMe, n = 3−5) is reported. The tethered donor functionality, which is appended via varying chain lengths to the silicon bridge, is introduced to examine possible intramolecular react…
Other| October 01, 1997 Electron-irradiation-induced phase segregation in crystalline and amorphous apatite; a TEM study A. Meldrum; A. Meldrum University of New Mexico, Department of Earth and Planetary Sciences, Albuquerque, NM, United States Search for other works by this author on: GSW Google Scholar L. M. Wang; L…
Barium oxide supported on magnesium oxide (Ba/MgO) exhibits unusual behavior as a catalyst for NO decomposition at Ba loadings of 11 mol % or greater. The catalytic activity is characterized by a sharp decrease in activity when the reaction temperature exceeds a certain value that depends on the partial pressures of N…