Materials Literature
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The theory of the depinning transition of elastic manifolds in random media provides a framework for the statistical dynamics of dislocation systems at yield. We consider the case of a single flexible dislocation gliding through a random stress field generated by a distribution of immobile dislocations threading throu…
A Maxwell–Wagner series capacitor model is proposed to explain anomalous dielectric properties of ferroelectric superlattices. The results of the model show that a superlattice consisting of normal ferroelectric layers separated by low-resistivity interfacial regions can account for most experimental results reported…
Magnetic properties and magnetic-field-induced strains (MFIS) have been investigated for off-stoichiometric Ni–Mn–Al Heusler alloys with an ordered L21 structure. A clear martensitic transformation in Ni53Mn25Al22 alloy was revealed below the Curie temperature. In the polycrystalline specimen, an irreversible relative…
We have developed a simple, fast, and flexible technique to measure optical scattering spectra of individual metallic nanoparticles. The particles are placed in an evanescent field produced by total internal reflection of light from a halogen lamp in a glass prism. The light scattered by individual particles is collec…
Suspended single-wall carbon nanotubes are used as substrates for deposition of various metals by evaporation. Deposition of many types of metals normally forms discrete particles on nanotubes due to a weak interaction between the metals and nanotubes. However, continuous nanowires of virtually any metal are obtained…
Abstract The U. S. Navy has a long-standing history of ship design using metals. With the improvements in weapon systems, it is becoming increasingly critical to design ship structures not only to satisfy the structural loading but also to exhibit additional multifunctional properties. This is becoming evident with st…
A new azobenzene-containing gelator for low-molar-mass liquid crystals (LCs) was synthesized. It can effectively gel nematic LCs such as E7 through the formation of a hydrogen-bonded network. Moreover, an intriguing self-assembly process was observed. When thin films of the E7/gelator mixture, cast on CaF 2 crystal wi…
Impregnation of polymers with supercritical CO 2 appears to be a promising technique in the area of polymer processing. The main aim of this paper is to measure the diffusion coefficients of a solute (a dyestuff) permeating a poly(ethylene terephthalate) (PET) film in a supercritical impregnating system at different w…
The early kinetic events of protein folding are an important part of the folding pathway, yet our understanding towards the process is limited. Information from the study of these early events can allow us to distinguish between the various models that have been proposed to describe the folding of a protein in real ti…
Electronic conductivity, σ EL, in solid-state films of alkanethiolate monolayer protected Au clusters (Au MPCs) occurs by a bimolecular, electron self-exchange reaction, whose rate constant is controlled by (a) the core-to-core tunneling of electronic charge along alkanethiolate chains and (b) the mixed valency of the…
The preparation of nanoscale lead sulfide (PbS) particles using a supercritical fluid processing technique is reported. The method is based on two simultaneous modifications to the conventional RESS (rapid expansion of supercritical solution) process. The first is to expand the supercritical solution into a liquid sol…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Novel Chiral Lead(II) Catalyst for Enantioselective Aldol Reactions in Aqueous MediaSatoshi Nagayama and Shū KobayashiView Author Information Graduate School of Pharmaceutical Sciences The University of Tokyo, CREST Japan Science and Technology Corporation (JST) Hong…
Die Elektrospray-Massenspektrometrie wurde erstmals benutzt, um anorganische oligomere Spezies in wässriger Lösung zu untersuchen. Unterschiedliche Doppelvier- und Doppeldreiringe konnten in Silicatlösungen verlässlich analysiert werden, wie mit der 29Si-NMR-Spektroskopie als unabhängiger Referenzmethode nachgewiesen…
Direct halogenations of polyoxometalates [NaPW11O39]6− and [PW9O34]9− led to [PW9O28Br6]3−, a molecular metal oxide with a fully brominated face (see picture). This methodology creates new opportunities for systematic chemistry at polyoxometalate surfaces.
A central Ag12 cluster core (see picture) that contains four more electrons than expected for a pure silver(I) compound is found in the title compound. This is confirmed by quantum chemical calculations at the DFT and MP2 level, which also show that d10–d10 interactions are not relevant for the cluster geometry.
A novel 5,10,15,20-tetraaryl-21-selenaporphyrin isomer with an inverted pyrrole ring, i.e., 5,10,15, 20-tetraaryl-2-aza-21-carba-22-selenaporphyrin (SeC-TArPH) has been produced by a [3 + 1] condensation of 2, 5-bis(phenylhydroxymethyl)selenophene and 5,10-ditolyltripyrrin. The reaction yielded 5,20-diphenyl-10,15-bis…
The relative viscosity of non-Newtonian concentrated emulsions of nearly spherical, non-Brownian droplets, in the absence of Coulombic and van der Waals interactions, is a function of four variables: the viscosity ratio ( K ), the volume fraction of dispersed phase (φ), the particle Reynolds number ( N Re,p ), and the…
Halogen-capped aniline trimers represent an important class of molecules that are no longer appropriate models for polyaniline, but they can nevertheless be expected to demonstrate useful properties in their own right. Such molecules are herein investigated by DFT (density functional theory) calculations of important…
π-Delokalisierung durch ausgedehnte Schichten hindurch besteht bei zweidimensionalen Netzwerkpolymeren der Formel [{M2(O2CCF3)4}2(TCNQ)(C7H8)3]∞ – dies geht sowohl aus den Strukturdaten als auch aus den spektroskopischen Daten hervor. Die Polymere setzen sich zusammen aus RuII,RuII- und RhII,RhII-Komplexen, die an TCN…
Hydroxyl radicals, generated by ionizing radiation in N2O saturated aqueous solutions, abstract H atoms from poly(methacrylic acid) at the methyl and methylene groups, and radicals 1 and 2 are formed, respectively. The reactions of the poly(methacrylic acid) radicals were investigated by pulse radiolysis (using optica…