Materials Literature
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Polarized X-ray absorption spectroscopy has been used to study the short-range structure of deposited films of V2O5 xerogel. The material is characterized by a layer of VO5 units with the V-O apical bond perpendicular to the basal (xy) plane. We have focused our attention along the z axis. Experiments were carried out…
This Account focuses on fundamental aspects and applications of the concept of "electron and proton reservoirs". Permethylated electron reservoir iron sandwich complexes, which were known to be excellent reducing agents in their neutral 19e Fe(I) form, have recently been shown to be stable strong oxidants in their dic…
We present a complete study of the Multiparticle Biased Diffusion-Limited Aggregation (MBDLA) model supplemented with surface difussion (SD), focusing on the relevance and effects of the latter transport mechanism. By comparing different algorithms, we show that MBDLA+SD is a very good qualitative model for electrodep…
Recent calculations by Vorobev and Malyshenko (JETP Letters, 71, 39, 2000) show that molecular hydrogen may stay liquid and superfluid in strong electric fields of the order of $4\times 10^7 V/cm$. I demonstrate that strong local electric fields of similar magnitude exist beneath a two-dimensional layer of electrons l…
One of the essential questions in the area of granular matter is, how to obtain macroscopic tensorial quantities like stress and strain from ``microscopic'' quantities like the contact forces in a granular assembly. Different averaging strategies are introduced, tested, and used to obtain volume fractions, coordinatio…
Nanocrystals of LaPO 4:Eu and CePO 4:Tb with a mean particle size of 5 nm and a narrow size distribution have been prepared by reacting the corresponding metal chlorides, phosphoric acid, and a base at 200 °C in tris(ethylhexyl) phosphate. Highly crystalline material was obtained as confirmed by X-ray powder diffracti…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLinear and Nonlinear Optical Properties of Photochromic Molecules and MaterialsJacques A. Delaire and Keitaro NakataniView Author Information Laboratoire de Photophysique et de Photochimie Supramoléculaires et Macromoléculaires (PPSM, UMR 8531 of CNRS), Ecole Normale Supérie…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpiropyrans and Spirooxazines for Memories and SwitchesGarry Berkovic, Valeri Krongauz, and Victor WeissView Author Information Soreq Nuclear Research Center, Yavne 81800, Israel Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel ELOP E…
The electronic properties of single-walled carbon nanotubes are shown here to be extremely sensitive to the chemical environment. Exposure to air or oxygen dramatically influences the nanotubes' electrical resistance, thermoelectric power, and local density of states, as determined by transport measurements and scanni…
Magneto-optical properties were measured for (La 1- x Pr x ) 0.7 Ca 0.3 MnO 3 ( x = 0, 0.25, 0.5, 0.75, 1) ceramic solid solutions, including temperature, magnetic field, oxygen isotope content and spectral dependences of the transverse Kerr effect (TKE). The TKE spectra after the transition to the ferromagnetic metal…
We investigate by lattice Monte Carlo simulation the kinetics of adsorption of isolated linear homopolymers onto a flat surface with a strong, short-ranged attraction for the segments. We focus on limiting cases corresponding to strong physisorption and chemisorption. Initially, the polymer has a conformation represen…
The structures of V 2 O 5 -TeO 2 glasses are investigated by means of 125 Te and 51 V static NMR spectroscopies and the local structures around the Te and V atoms are discussed in detail from the respective NMR spectra. The fraction of TeO 3 trigonal pyramids increases and that of TeO 4 trigonal bipyramids decreases w…
Response surface methodology (RSM) and 3-level-3-factor fractional factorial design were used to evaluate the effects of synthesis parameters, including reaction time (4 to 8 h), temperature (110 to 130 degrees C), and substrate molar ratio of fatty acid methyl esters (FAME) from soybean oil to methyl glucoside (4:1 t…
We investigated the relaxation of a binary polybutadiene/polyisoprene blend after the cessation of steady-state shear using both in situ optical microscopy (OM) and light scattering (LS). Through fast Fourier transforms of the micrographs, we were able to directly relate our LS patterns with the real space morphology.…
The superexchange interactions in four three-center model systems A-L-B, for A and B being paramagnetic centers and L a diamagnetic bridging ligand, are analyzed by valence bond configuration interaction models in combination with fourth-order perturbation theory. We analyze the four distinct cases where a bridging li…
A novel cyclic octanuclear chromium(III) complex with hydroxo and acetato bridging ligands was isolated and its structure determined by X-ray crystallography. The complex [Cr8(OH)12(OAc)12] (1) (OAc- = CH3CO2-), as found in crystals of 1.34H2O, is obtained by refluxing an aqueous solution of the trinuclear "basic" chr…
Microbial degradation of thermally synthesized poly(aspartic acid) (PAA) was investigated. A PAA-P1 sample (Mn, 7500; Mw, 20,000; number of branched units/100 monomer units, 3.1) was completely degraded in natural river water within 15 days at 25 degrees C. A new PAA-degrading bacterium (strain KP-2: JCM10638) was iso…
The in-depth structural analysis of spherulites of artificial cellulose, formed by the enzymatic polymerization of cellobiosyl fluoride, is reported. Both positive- and negative-type spherulites were observed by polarization optical microscopy. Scanning electron microscopy revealed that the negative spherulites have a…
The mechanism of the selective catalytic reduction (SCR) of NO by C 3 H 6 on Cu−Al 2 O 3 catalysts, which consist of highly dispersed Cu 2+ ions in the surface aluminate phase, are investigated by in-situ FTIR spectroscopy. During NO + C 3 H 6 + O 2 reaction, the acetate is produced via the partial oxidation of C 3 H…
We study the surface dynamics of silica films grown by low pressure chemical vapor deposition. Atomic force microscopy measurements show that the surface reaches a scale invariant stationary state compatible with the Kardar-Parisi-Zhang (KPZ) equation in three dimensions. At intermediate times the surface undergoes an…