Materials Literature
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High voltage dc is required in a wide range of consumer, commercial, and military applications. Presently available PD analysis for dc systems can extend far beyond the old-fashioned "not more than 'n' PD pulses per minute over a given magnitude".
The development of advanced structural ceramics , which are used in specific components working under extreme conditions, require their microstructural analysis. The microscopy of structural ceramics is reviewed, beginning with various imaging techniques. The important microstructural features of three ceramics—alumin…
The semiconductor–metal phase change in VO 2 at approximately 67°C, which results in great changes in its optical, electrical, and magnetic properties, is described in detail. The synthesis of VO 2 thin films by the sol‐gel method is outlined and the structure and optical properties are characterized, including hyster…
A new analytic model, based on the interference of waves, and numerical calculations are exploited for analyzing the spectral behavior of the transmitted and reflected intensities from metal-based grating–waveguide structures. The results reveal that strong intensity changes can occur near resonance with resonance ban…
The best models available in the literature to analyze gelation in the diepoxide−cyclic anhydride copolymerization are based on the mean-field approach. A kinetic model was developed to account for the nonrandom steps of the copolymerization. Two kinetic schemes were employed with one including chain transfer steps. P…
All eukaryotic protein kinases share a conserved catalytic core. In the catalytic (C) subunit of cAMP-dependent protein kinase (cAPK) this core is preceded by a myristylation motif followed by a long helix with Trp 30 at the end of this A-helix filling a hydrophobic cavity between the two lobes of the core. To underst…
In order to better understand the gelation process associated with collagen assembly, and the mechanism of the in vitro morphogenetic phenomenon of "matrix-driven translocation" [S.A. Newman et al. (1985) Science, 228, 885-889], the viscosity and elastic modulus of assembling collagen matrices in the presence and abse…
Broad-band conductive spectroscopy covering a 10 mHz–1 GHz frequency range has been employed to examine the ionic motions in polypropylene oxide (PPO) complexed with 0–1% LiClO 4 at temperatures from -60 °C to 100 °C. The dc conduction appears as a plateau of the conductive spectra in their medium frequency range. As…
The present work showed a significant antinociceptive activity in the tannin fraction (TF) extracted from the bark of Myracrodruon urundeuva Fr. All. This inhibitory effect was demonstrated not only against abdominal contractions but also in the formalin test in mice. In the first case, at doses of 0.1 and 1 mg/kg, i.…
Upon reaction with osmium tetraoxide a series of porphyrins and chlorins were converted into the corresponding vic- dihydroxychlorins and bacteriochlorins. The presence of an electron-withdrawing substituent at a peripheral position on the porphyrins or chlorins deactivated that particular pyrrole unit toward oxidatio…
The electrochemical oxidation of several oligopyrroles, either unprotected, partially blocked, or totally blocked on their α-terminal positions or N-substituted, has been investigated in acetonitrile by cyclic voltammetry. For all the studied oligopyrroles, reversible voltammograms have been obtained at moderate to hi…
Six polyurethanes containing coumarin dimer components in the main chain have been prepared by polyaddition of diisocyanates with anti head-to-head 7-hydroxycoumarin dimer or anti head-to-tail 7-hydroxy-4-methylcoumarin dimer. 7-Acetoxycoumarin and 7-acetoxy-4-methylcoumarin were first prepared and then photodimerized…
Self-diffusion coefficients obtained by the NMR spin-echo method are reported for water at temperatures below 0 °C and at pressures up to 350 MPa in the liquid region bounded by the ice I and ice III phases. The data are compared with other measurements in this region.
We report a shear wave reflection technique which allows time- and temperature-dependent measurements of the complex dynamic shear modulus (G*=G′+iG′′) or the dynamic shear viscosity (ηs′) in the ultrasonic frequency range (3–40 MHz). The shear wave reflection method developed by Mason et al. [Phys. Rev. 75, 936 (1949…
The bacterial copolyester poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) was produced with Alcaligenes eutrophus DSM 545 from glucose and sodium propionate in a fed-batch fermentation with both nitrogen limitation and low dissolved-oxygen concentrations. When the dissolved-oxygen content was kept between 1 and 4% of ai…
A high-resolution calorimetric study has been made on the smectic-A to nematic phase transition in liquid crystals perturbed by the dispersion of 70-\AA{}-diam silica spheres (aerosils). The specific heat peak of this transition decreases in amplitude and shifts to lower temperatures with increasing silica density. Ho…
Photoexcited [Ru(bpy) 3 ] 2+ (bpy = 2,2‘-bipyridine) can be quenched with [Co(NH 3 ) 5 Cl] 2+ to give [Ru(bpy) 3 ] 3+; this photogenerated oxidant ( E 0 = 1.25 V vs NHE) reacts with horseradish peroxidase isoenzyme c (HRPc) to produce oxidized protein species. Spectra and kinetics measured by laser-flash transient spe…
The diffusion and gelation dynamics of nonsolvent-induced phase inversion in several polyethersulfone (PES)/solvent/nonsolvent systems are observed using a dark-ground optical technique. The observed dynamics are correlated with the resultant morphologies of the solidified gels obtained via scanning electron microscop…
Abstract The Fourier transform Raman spectra of the kaolinite minerals have been measured in the 50–3800 cm −1 region using near infrared spectroscopy. Kaolinites are characterized by remarkably intense bands in the 120–145 cm −1 region. These bands, attributed to the O-Si-O and O-Al-O symmetric bending modes, are bot…
The Bacillus subtilis L-arabinose metabolic genes araA, araB and araD, encoding L-arabinose isomerase, L-ribulokinase and L-ribulose-5-phosphate 4-epimerase, respectively, have been cloned previously and the products of araB and araD were shown to be functionally homologous to their Escherichia coli counterparts by co…