Materials Literature
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The synthesis of three third-generation dendrimers that selectively carry one aryl bromide functional group in the first, second, or third generation, respectively, is described. These functions, regardless of their location, can be chemically modified by Suzuki cross-coupling chemistry with p-tert-butylbenzene boroni…
The microstructures of different high-temperature prepared oxides of the (1− x )Y 0.5 Zr 0.5 O 1.75 − x Y 0.75 Nb 0.25 O 1.75 (0 ≤ x ≤ 1) system have been studied by selected-area electron diffraction and high-resolution transmission electron microscopy. The materials show a modulated fluorite-type structure mainly du…
Application of hydrostatic pressure (≤ 10.5 kbar) on the two-dimensional spin transition compound [Fe(btr) 2 (NCS) 2 ]·H 2 O (btr = 4,4‘-bis-1,2,4-triazole) results in an unexpected stabilization of the HS state. On release of the pressure, the HS state is found to be partially trapped. After thermal relaxation of the…
We study both theoretically and experimentally the nonlinear interaction between an intense surface acoustic wave and a two-dimensional electron plasma in semiconductor-piezocrystal hybrid structures. The experiments on hybrid systems exhibit strongly nonlinear acousto-electric effects. The plasma turns into moving el…
Experimental solubilities are reported for anthracene dissolved in ternary methyl tert -butyl ether + 1-propanol + cyclohexane, methyl tert -butyl ether + 2-propanol + cyclohexane, methyl tert -butyl ether + 1-butanol + cyclohexane, methyl tert -butyl ether + 2-butanol + cyclohexane, and methyl tert -butyl ether + 2-m…
Given the increasingly sophisticated tools available to acquire, store and process partial discharge measurements, it is imperative that the mechanisms of partial discharge degradation and the factors influencing the nature, form, extent and rate of degradation are elucidated. This will permit correlation among the me…
Epoxy resins are used in the production of high-voltage insulation components. Partial discharges, inherent in high-voltage installations, degenerate the resinous material and cause degradation of the insulation thus reducing the working life of the component. An understanding of the nature of the chemical changes tak…
Vanadium pentoxide (V 2 O 5 ) gels are suspensions of V 2 O 5 ribbonlike particles dispersed in water. At volume fractions larger than 0.7%, they form a lyotropic nematic liquid-crystalline phase. We investigate here three different methods of synthesis (by ion-exchange, from peroxovanadic species, and by dissolution…
Deacetylation of chitin under autoclaving conditions (15 psi/121 degrees C) was evaluated for the preparation of chitosan under different NaOH concentrations and reaction times. Deacetylation was effectively achieved by treatment of chitin under elevated temperature and pressure with 45% NaOH for 30 min and a solids/s…
Char samples were prepared from five Australian black coals at different temperatures using a well-characterized drop-tube furnace. The characteristics of resultant chars and their parent coals were determined by such techniques as chemical analysis, XRD (X-ray diffraction), FESEM (field emission scanning electron mic…
Transmission electron photograph shows a single CdS nanorod. The nanorod was synthesized via arrested precipitation from cadmium and sulfur ions in a micellar solution. The photograph exhibits clear lattice planes and faceted structures on the tip of the nanorod.
Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used to examine the adsorption behavior of bovine serum albumin (BSA) and bovine fibrinogen on titanium in phosphate buffer pH 7.4, over the temperature range 295−343 K. It was shown that the surface charge density is directly proportional to the…
We have successfully prepared CdSe nanowire arrays by direct-current electrodeposition in porous anodic aluminum oxide templates from a dimethyl sulfoxide solution containing CdCl 2 and elemental Se. Electron microscopy results show that the length, diameter, and direction of growth of the nanowires are quite uniform.…
The construction of an electromechanical actuator with large displacement, with fast time response, and without electrolytic gas evolution in pure water or saline is described. Improvement in the previously reported platinum−polymer electrolyte membrane composite was made by switching to gold, deposited by the “impreg…
What are the mechanisms leading to the shape relaxation of three dimensional crystallites ? Kinetic Monte Carlo simulations of fcc clusters show that the usual theories of equilibration, via atomic surface diffusion driven by curvature, are verified only at high temperatures. Below the roughening temperature, the rela…
The chemistry of silicones is summarized by following the steps necessary to produce a two-part, platinum-cured silicone containing vinyl-stopped polydimethylsiloxane, Si-H-on-chain siloxane, platinum catalyst and catalyst inhibitor. The process begins with silicon dioxide and follows the steps of conversion to sand t…
Poly(methyl methacrylate)–clay composites were synthesized through free-radical solution polymerization of methyl methacrylate in the presence of clay that was preintercalated with dodecylammonium or hexadecyltrimethylammonium ions. Neither the diffraction peak from the (001) plane nor the 00l reflections for the (001…
In order to check our physical model for partial discharges (PDs) in a tree channel, the light emission from a PD in an actual tree was observed. The experimental results agreed with the model. By using the model, conditions for the formation of typical phase-amplitude-number (ϕ- q - n ) pattern of PDs from treeing wa…
The heterogeneous photodegradation of tetrachloroethene in air proceeded on clay particles (halloysite) under photoillumination (>300 nm) with an induction period. The induction period and the tetrachloroethene removal rate were not sensitive to the tetrachloroethene partial pressure or the relative humidity. The phot…
Previously synthesized polymers (pellets or powders) and reactive monomers (lactams) can be used as starting materials in direct centrifugal molding for the manufacture of products with a circular section. The direct centrifugal molding of ϵ-caprolactam has been investigated in order to obtain Nylon 6-based products a…