Materials Literature
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The dynamics of the fragile glass-forming liquid m -toluidine is investigated by time-resolved optical Kerr effect. A heterodyne detection technique allows to analyze the signal over four decades in time (10 −13 s to 10 −9 s), in the temperature range 250 K–295 K. The results of data analysis remarkably agree with the…
Abstract Ground rubber tire (GRT) particles of different sizes were characterized and the effect of these particles in a natural rubber (NR) compound was studied. It is found that smaller particles contain less polymer, but have higher amounts of fillers and metals with respect to polymer. NR compound containing small…
Porous silicon is a new material with a high potential for the fabrication of electronic devices and solar cells. Changes in the morphology during thermal treatment are decisive for semiconductor processes such as epitaxy on porous silicon. We introduce a two-dimensional model to simulate the annealing behaviour of po…
Bisthienylethene (BTE)–based photochromic switches exhibit high resistivity, rapid response, and thermal and photo-stability. The synthesis of the BTE derivative shown in the Figure, a new kind of structure for photochromic polymers, is reported. The switching properties—including photo-fatigue resistance—of 1 and its…
Series of novel thermotropic liquid crystalline compounds which serve as models for mesogenic diols have been synthesized. The mesogen molecules are constructed from 1,4-disubstituted benzene rings linked through ester and azomethine units. Based on the number of phenyl rings, a tetrad or pentad classification has bee…
[reaction: see text] Synthesis of new meso aryl 30pi heptaphyrins 2, 3, and 4 is achieved. Spectroscopic studies reveal that 2, 3, and 4 are aromatic and possess an inverted structure.
String-shaped reconstituted smooth muscle (SM) fibers were prepared in rectangular wells by thermal gelation of a mixed solution of collagen and cultured SM cells derived from guinea pig stomach. The cells in the fiber exhibited an elongated spindle shape and were aligned along the long axis. The fiber contracted in r…
An easy synthesis of phthalocyaninatotitanium(IV) compounds substituted with bidentate ligands in the axial position is described. Using strongly chelating oxygen or sulfur donor ligands, the reaction of PcTiO with chelating agents leads to the formation of PcTiX complexes with X ≡ oxalate [Formula: see text], catecho…
The magnetoresistance (MR) and transport properties of both single-crystal and polycrystalline samples of La 0.7 Ca 0.3 MnO 3 - δ (LCMO) have been investigated to elucidate their magneto transport behaviors near and below the Curie temperature T C . We find that negative MR is heavily dependent upon the surface morpho…
Recent research suggests that the charge carriers in the paramagnetic state of the magnetoresistive manganites are small polarons. Here we report studies of the oxygen-isotope effects on the intrinsic resistivity and thermoelectric power in several ferromagnetic manganites. The precise measurements of these isotope ef…
X-ray absorption measurements of solid and liquid AgBr in the $T=30--927K$ range of temperature have been performed using synchrotron radiation. Accurate short-range structural parameters are determined using simultaneous Ag and Br K-edge EXAFS refinement in the framework of the GNXAS method for data analysis. Results…
The salient features of the current burst model for the Si–electrolyte interface is presented in a short overview. In the current burst model, charge transfer at the Si–electrolyte interface is localized in space and time and intrinsically stochastic; all phenomena encountered in Si electrochemistry then are manifesta…
Nanostructured carbon/silica hybrid materials and poly(furfuryl alcohol)/silica xerogel are prepared and characterized here. In the key synthetic step, cation-induced polycondensation of furfuryl alcohol occurs simultaneously with a sol–gel process involving tetraethoxysilane and water to yield the xerogel, which is s…
ABSTRACT Batch extraction of zein from dry‐milled whole corn with ethanol was optimum with 70% ethanol in water, an extraction time of 30–40 min, and temperature of 50°C. High yields (60% of the zein in corn) and high zein contents in the extracted solids (50%) were obtained at a solvent‐to‐solids ratio of 8 mL of 70%…
ADVERTISEMENT RETURN TO ISSUECommunicationNEXTAqueous Preparation of Highly Dispersed Molybdenum SulfideI. Bezverkhy, P. Afanasiev, and M. LacroixView Author Information Institut de Recherches sur la Catalyse, 2, Avenue Albert Einstein, 69626 Villeurbanne Cedex, France Cite this: Inorg. Chem. 2000, 39, 24, 5416–5417Pu…
The edema factor exotoxin produced by Bacillus anthracis is an adenylyl cyclase that is activated by calmodulin (CaM) at resting state calcium concentrations in infected cells. A C-terminal 60-kDa fragment corresponding to the catalytic domain of edema factor (EF3) was cloned, overexpressed in Escherichia coli, and pu…
The formation of coils is common in nature when achiral symmetry breaking occurs. Here we describe spectacular examples of single, double and triple coils observed in smectic liquid crystal phases of achiral banana-shaped molecules. Such molecules form chiral smectic phases due to two symmetry-breaking instabilities:…
Raman scattering from individual single-wall carbon nanotube (SWNT) bundles was measured using confocal optical microscopy with 632 nm laser excitation. The Raman scattering from metallic SWNTs was found to depend sensitively on adsorbed oxidizing molecules. Tangential mode Raman lines of HNO 3 -treated SWNTs exhibite…
A new efficient laboratory method of preparation of chlorodimethylsilane (Cl(CH 3 ) 2 SiH) has been elaborated, which is a modification of the Eaborn et al. method (34) and is based on a transsilylation reaction of substituted (amino)dimethylhydrosilanes, R 2 NSiMe 2 H (R 2 = Me 2 , Et 2 , (CH 2 ) n , etc.) with dimet…
Three composites that were 96% alumina were mixed and uniaxially dry‐pressed into bars and pellets; all had monoclinic SrAl 2 Si 2 O 8 as an intergranular phase. The diffraction patterns, microstructure, density, dielectric properties, strength, and toughness were measured. The first composition, which contained cryst…