Materials Literature
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The electrochemistry of polyaniline (PANI) films deposited on platinum microelectrodes has been studied in a wide pH region, at constant ionic strength. Cyclic voltammograms, recorded at a sweep rate of 100 V s–1 indicate that the films remain electroactive at pH values as high as 9 provided that the films are only sw…
The decrease in efficiency of ZnS:Ag,Al phosphor powders under high cathode-ray excitation densities has been investigated in a wide range of Ag concentrations (18–1560 ppm) with the Al/Ag ratio fixed at 1.5. Two distinct regions have been observed in this saturation behavior. For low Ag concentrations up to some 100…
Abstract To produce reaction products with 100% chemical selectivity, and to attain much higher turnover rates and number of turnovers, the development of new methods of catalyst preparation are necessary. Precise control of particle size, the separation between catalyst particles and their superior chemical and therm…
Modeling of sacrificial layer etching can be done by combining the diffusion rates of etchants in solution and the chemical reaction rate. Steady‐state diffusion is estimated for diffusion coefficients in water on the range of as observed from an independent experiment. Likewise, the chemical reaction rates (or initia…
Two refined crystal structures of aspartate aminotransferase from E. coli are reported. The wild type enzyme is in the pyridoxal phosphate (PLP) form and its structure has been determined to 2.4 A resolution, refined to an R-factor of 23.2%. The structure of the Arg292Asp mutant has been determined at 2.8 A resolution…
Effects of flame treatment on polyethylene (PE) surfaces have been studied using contact-angle measurements, attenuated total reflection infrared spectroscopy (ATR-IR), X-ray photoelectron spectroscopy (XPS), and an adhesion test. A significantly higher level of surface oxidation was induced by flame treatment on PE t…
The coefficient of friction of 14 prescribable bath emollients was determined using porcine skin attached to a loaded plunger placed through a bearing in a friction-measuring carriage, held above a reciprocating table powered by a DC motor. The carriage was mounted in low-friction rollers, and restrained by a piezo-el…
Zone refining has been tried on high-purity aluminum produced by a combination of the three-layer electrolytic refining process and the segregation process. The cropping procedure was effective in increasing the efficiency of zone refining. The highest residual resistance ratio R(300 K)/R(4.2 K) obtained was about 900…
Photophysical properties have been measured for five merocyanine dyes having (i) different alkyl substituents on the thiobarbiturate subunit [i.e. ethyl (butyl Merocyanine 540), or hexyl], (ii) the sulfonate group replaced with a methyl group, or (iii) the benzoxazole residue replaced with 1,2-naphthoxazole, and for o…
The effects of plasticizer, polyethylene glycol (PEG-600), on the sucrose permeability, void volume and morphology of cellulose acetate free films were investigated. The sucrose permeability of cellulose acetate free films was found to decrease with increasing PEG-600 to a minimum and increase dramatically when they w…
The order of reactivity of perfluorinated dienes towards methanol is 3 > 21 and the process is activated by release of angle strain. The diene 1 is hydrolysed to give perfluorotetramethyl-furan and the corresponding thiophene, is obtained by an analogous process using K2S. Hydrolysis of compounds 2 and 3 yields diketo…
Titanium alloys absorb large amounts of hydrogen and it is desorbed in vacuum at elevated temperatures. This paper describes equiaxed grain refinement and the improvement of mechanical properties of titanium alloys utilizing this phenomenon. Particular attention has been paid to the control of three different types of…
A thorough understanding of the wood surface is required to engineer adhesive bonding in composite applications.A surface analysis technique, dynamic contact angle (DCA) analysis, was used to examine the effects of temperature on the wood surface as measured by the contact angle and surface energy.A hydrophobic surfac…
Lys15 in Escherichia coli glycogen synthase, which is specifically labeled by adenosine diphosphopyridoxal, is mainly involved in binding of the substrate ADP-glucose (Furukawa, K., Tagaya, M., Tanizawa, K., and Fukui, T. (1993) J. Biol. Chem. 268, 23837-23842). We have found that the mutant glycogen synthase in which…
Abstract Two simple related methods for exclusively preparing well‐developed tetragonal bipyramidal crystals of calcium oxalate dihydrate at moderate supersaturations and at ambient temperature are reported. These crystals have an average length of 5.7–7.2 μm and are easy to wash and filter. One of the methods is suit…
Studies are reported on decay and recovery of hydrophobic properties on clean and contaminated surfaces of silicone rubber based RTV coating. Treatment that led to hydrophobicity losses were water immersion and water condensation with and without a presence of dc electric field. Contact angles (receding angles) and su…
Mullite and ZrO 2 ‐toughened mullite (ZTM) were joined with Ag─Cu eutectic braze alloys that contain Ti or Zr as active elements. Although neither the alloy compositions nor the processing conditions were optimized, four‐point bend strengths of joined bars were as high as 108 MPa. Joining reactions were studied by con…
The hexafunctional initiator C6[(CH2)2p-C6H4CH(Cl)Me]6 is synthesized by Fe(η-C5H5)+ induced hexabenzylation of C6Me6 followed by regiospecific acetylation, NaBH4 reduction and chlorination, and allows the living cationic polymerization of styrene which yields hexaarm star-shaped polymers.
A series of nonmesogenic N-acylated derivatives (2) of 1,10-diaza-4,7,13,16-tetrathiacyclooctadecane (1) affords stable cationic complexes upon reaction with [Cu(MeCN)4][PF6]. The products [Cu(2)] [PF6] show thermotropic mesomorphism as a result of copper(I) complexation. Optical microscopy, calorimetry, and low-resol…
Sputtered multilayer films were studied by Fourier‐transform infrared spectroscopy (FTIR) and x‐ray diffraction (XRD), and their bonding structure and crystallization were compared with composite films. The thickness ratio of the multilayer films was fixed at 1:3, and the monolayer thickness was varied from 0.3 to 60…