Materials Literature
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Discs of poly(aniline)-silver-polymer electrolyte particulate composites exhibit rapid and reversible changes in their microwave impedance when small electric fields are applied across them in a coaxial line test set in a resonant condition. The effect of composition on the cyclic voltammetry and microwave characteris…
Ferroelectric thin films of bismuth‐containing layered perovskite PbBi 2 Nb 2 O 9 have been prepared by a metalorganic decomposition (MOD) method. Random and highly c‐oriented films of the same starting composition have been obtained under different intermediate‐ and high‐temperature heat treatments. A comparison of t…
Eu 3+ -doped SiO 2, Al 2 O 3 −SiO 2, and P 2 O 5 −SiO 2 glasses were prepared by a sol−gel method from metal alkoxides, and their persistent spectral hole burning (PSHB) properties were investigated in relation to the local environment of the Eu 3+ ions in glass. Fluorescence line narrowing spectra indicated that Eu 3…
Poly(D,L-lactide-co-ethylene methyl phosphate) was synthesized by ring-opening polymerization of D,L-lactide (D,L-LA) and ethylene methyl phosphate (EMP) in bulk with Al(OiPr)3 as initiator. The influence of reaction conditions such as polymerization time, polymerization temperature and initiator concentration on the…
This research was directed toward a better understanding of the mass-transfer processes that occur in distillation columns containing structured packings. These packings are designed to create an-extensive gas−liquid interfacial area, through a combination of packing surface texturing and geometrical arrangement in th…
The photooxidation of bulk (1 mm) and thin (˜80 μm) samples of unfilled PVC free of photostabilizers was studied in various photoreactors in the 40–70°C temperature range. In bulk samples, the thickness distributions of photoproducts (carbonyls, conjugated polyenes, chain scission, crosslinks) and thermal stabilizer (…
The unusual three-dimensional tunnel framework of K2Ag3CeTe4 is built from the linking of [Ag2CeTe4]3- layers with Ag. This generates tunnels with an oval-shaped cross section with an accessible opening of 7.9 Å × 2.9 Å × 5.3 Å. These dimensions are large enough to permit the K+ cations to be accessible via topotactic…
Abstract The chemical composition of hydrothermal chlorite was determined by means of more than 200 electron microprobe analyses (EMPA) in almost all of the 70 chlorite-bearing samples taken from 5 boreholes in a study of the active geothermal system of Los Humeros, Mexico. Bulk rock composition of 6 different volcani…
It is well established that the dispersion of nanosized metal particles in a polymer matrix can induce nonlinear optical properties, yet very little is known about the effect of semiconducting transition metal oxide nanoparticles on luminescence properties of conjugated polymers. In this paper, we report the synthesis…
The pyridoxal form of alanine racemase of Bacillus stearothermophilus was converted to the pyridoxamine form by incubation with its natural substrate, D- or L-alanine, under acidic conditions: the enzyme loses its racemase activity concomitantly. The pyridoxamine form of the enzyme returned to the pyridoxal form by in…
Computer simulations of the dynamics of a colloidal particle suspended in a fluid confined by an interface show that the asymptotic decay of the velocity correlation functions is algebraic. The exponents of the long-time tails depend on the direction of motion of the particle relative to the surface, as well as on the…
In this article we describe research into the molecular design features for potential thermotropic biaxial nematogens of low-molar mass. We discuss how we can systematically change the shape of molecular structures in view of this aim of our work. The optical biaxialities of the materials prepared were tested through…
Other| December 01, 1998 Cation dynamics and premelting in lithium metasilicate (Li 2 SiO 3 ) and sodium metasilicate (Na 2 SiO 3 ); a high-temperature NMR study Ann M. George; Ann M. George Stanford California, Department of Geological and Environmental Sciences, Stanford, CA, United States Search for other works by…
Abstract We report the electronic structures of three large band gap borates β‐BaB 2 O 4 , YBO 3 and LuBO 3 , and corresponding binary oxides BaO, Y 2 O 3 , Lu 2 O 3 and B 2 O 3 . The main objective of this investigation is to explore how the electronic structures of complex oxides relates to their binary oxides, and…
The solution and adsorption behavior of a series of diblock copolymers of hydrophobic poly(dimethyl siloxane) and hydrophilic poly(2-ethyl-2-oxazoline) was studied. These block copolymers formed large polydisperse micelles in an aqueous solution. The critical micelle concentration was lower than 2 mg L -1 . The adsorp…
Abstract Lode, a dioctahedral illite-rich clay from Latvia belonging to the mica group of clay minerals, undergoes thermal transformation via a series of structurally disordered intermediate phases. Despite containing high levels of paramagnetic Fe substituted into the octahedral sites, 29 Si and 27 Al magic angle spi…
The optical dielectric function of zinc is measured by excitation of surface plasmon-polaritons on a silica prism coated in MgF2 and zinc in the Kretchmann configuration and on a zinc-covered silica grating for a range of wavelengths in the visible spectrum. By exciting the surface plasmon at the zinc-MgF2 or zinc-gra…
Cellulose carbamate and ester derivatives were synthesized in homogeneous solutions of lithium chloride (LiCl)/N,N-dimemyl-acetamide (DMAc) by the reaction of cellulose with ethyl 4-isocyanatobenzoate and the activated esters of N,N-dimethyl-aminobenzoic acids. Comparative reactions were performed with phenyl isocyana…
The inhibiting effect of Schiff base N,N´-o-phenylen-bis (3-methoxysalicylaldenimine), designated as V-ph-V, on corrosion of copper in 1.0 M hydrochloric acid (HCl) or 1.0 M sodium chloride (NaCl) solutions under various conditions was studied using the potentiostatic polarization method and the alternating current (A…
BaTiO 3 particles of ultrafine size and high crystallinity were produced by a spray−coprecipitation technique. To improve stability, titanium isopropoxide was acylated using acetic acid. The sol solutions were prepared by mixing the titanium acylate with aqueous barium acetate . Spray−precipitation was performed in co…