Materials Literature
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The physical significance of the first diffraction peak in glassy Se is discussed in the light of recent experimental results regarding the temperature dependence of the parameters characterizing the first peaks in the elastic S(Q,\ensuremath{\omega}=0) and static S(Q) structure factors. The rather different behavior…
Trifluoroacetic acid and ZnCl2 have been used as the initiating system for the living cationic polymerization of β-(vinyloxy)ethyl cinnamate (VEC). In contrast to a previous initiating system [EtAlCl2 and 1-(isobutoxy)ethyl acetate], the use of the new system led to excellent agreement between the molar masses of PVEC…
A new optically active (R)-3-ethylmercapto-2-methylpropionic acid has been synthesized using D(-)—2,10-camphorsultam as a chiral auxiliary. The optical purity of the acid obtained was greater than 98 per cent. Its derivatives, (R)-4-(3-ethylmercapto-2-methylpropionyl)phenyl 4′-alkoxybiphenyl-4-carboxylates (EMMPPmBC;…
Porous silica glass was prepared by sol-gel process from tetraethoxysilane (TEOS). The effects of solvents (water, ethanol), drying condition, heat treatment temperature on specific surface area and pore size distribution of porous silica were investigated. Gelation process accelerates with an increase of H2O content,…
Pd and its fee substitutional alloys which form hydride phases exhibit hysteresis. If Pd-Ni alloys have been hydrided and then dehydrided a number of times at a moderate temperature, the hysteresis is reduced. The reduction of hysteresis increases with increase of X Ni to 0.15 and, if the X Ni = 0.15 alloy is hydrided…
Elastic recoil detection analysis (ERDA) was performed to determine hydrogen concentration profiles near the (100) surfaces of epitaxially grown diamond films. Microwave plasma chemical vapor deposition (CVD) was used for the growth. At the end of the growth, the substrates were treated with and without exposure to H…
The dislocation loops in rutile produced after irradiation by 0.4-1 MeV electrons at various temperatures have been analyzed. Loops formed during electron irradiation at 400°-500°C were pure edge interstitial of the type <100>{100} and were unfaulted. After leaving rutile specimens irradiated at high temperature for a…
Single crystal-silicon quantum wells with SiO2 barriers have been grown from SIMOX silicon-on-insulator substrates. Photoluminescence in the red and near-infrared is observed for average well width &lt;8 nm, with peak signal for 2-nm average width. The luminescence spectrum is independent of well width for SiO2 ba…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn Insect Antifeedant Limonoid from Turraea niloticaMichael D. Bentley, Geoffrey O. Adul, A. Randall Alford, Fu-Yung Huang, Leslie Gelbaum, and Ahmed HassanaliCite this: J. Nat. Prod. 1995, 58, 5, 748–750Publication Date (Print):May 1, 1995Publication History Published onlin…
Both one-dimensional two-phase Stefan problems with the thermodynamic equilibrium condition $\theta (R(t),t) = 0$, and with the kinetic rule $\theta (R(t),t) = - \varepsilon \dot R(t)$ at the moving boundary $x = R(t)$ are considered. We study the properties of the regular solutions of the problem with equilibrium con…
The title compounds have an isotypic averaged structure but differ in significant detail with respect to disorder. Disorder diffuse scattering has been studied in situ up to 1150 K with a heating camera and X-ray films and an image-plate system at the synchrotron source Deutsches Elektronensynchrotron/HASYLAB. With th…
Abstract The mechanism of reinforcing rubber with carbon black particles is investigated by comparing the strain energy density functions of pure and reinforced rubbers. Finite deformation biaxial extension experiments are used to measure the strain energy density. The functional form of the reinforced system, which h…
Surface electrode patterns with systematic changes of electrode gap distances and widths have been developed to investigate the averaging effect in the current-voltage ( I-V ) measurements of ZnO varistors. Varistor breakdown voltages, V B , and the nonlinear exponent, α, were obtained from the I-V measurements. The α…
An approach to the R ‐curve behavior of 2‐D woven ceramic matrix composites is proposed. This approach takes into account the presence of a process zone at the crack tip. The strain energy release rate is determined using an equivalent system of two specimens free of process zones. The process zone size is determined…
The penetration performance of uranium alloy kinetic energy (long rod) projectiles are superior to that of equivalent projectiles manufactured from high-density tungsten-based composites. Prior research efforts seeking improvements in the penetration capabilities of tungsten penetrator materials have focussed on incre…
Alloys of Dy0.73Tb0.27Fe2−xNix [0≤x≤2] were prepared and the lattice parameters obtained at room temperature showed a deviation from Vegard’s law owing to the presence of magnetovolume effect. Magnetization studies were carried out up to an applied field of 10 kOe in the temperature range 4.2–750 K. Magnetization data…
An extensive review of recent developments in the synthesis, crystallization, structure and morphology of poly(phenylene sulphide) (PPS) polymers is presented. There has been a vast proliferation of knowledge about such thermoplastic matrix materials and the more important findings are now discussed, mainly for the li…
Abstract The gallium sulphide cubane compounds [(Me 2 EtC)GaS] 4 and [(Et 2 MeC)GaS] 4 , have been synthesised, and their potential as MOCVD precursors for GaS is discussed. The molecular structure of [(Et 2 MeC)GaS] 4 has been determined by X‐ray diffraction. In addition, the vapour phase structure of the GaSe precur…
Abstract The polarizability and hyperpolarizabilities of nitrophenols as model compounds for studying nonlinear optics have been investigated at the Hartree‐Fock level of approximation by means of the Dalgarno Uncoupled Hartree‐Fock (DUHF) or Sum Over Orbitals (SOO) method. The additive character and the charge transf…
Undersaturated and supersaturated zincate solutions have been prepared electrochemically and chemically, and studied using nuclear magnetic resonance (NMR) spectrometry and extended x‐ray absorption fine structure (EXAFS). 67 Zn NMR spectroscopy shows only one resonance line, the area of which first increases with the…