Materials Literature
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Self-assembly of cyclic bis-urea compounds takes place even at low concentrations to form very thin fibers which give a three-dimensional network in the solvent. The X-ray structure indicates that the molecules assemble into one-dimensional chains in which each unit forms eight hydrogen bonds with its neighbors (see p…
An interfacial stress rheometer has been constructed to study the rheology of Langmuir films subjected to time-dependent flows. A magnetized rod resides at the air−water interface and is set into oscillation by applying a sinusoidal magnetic field gradient. Analysis of the amplitude and phase of the resulting rod moti…
Electrosynthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) films was performed in a micellar aqueous solution containing sodium dodecyl sulfate (SDS) by cyclic voltammetry, chronoamperometry, and chronopotentiometry on a platinum electrode. The electrocatalytic effect of SDS was characterized by a significant decrea…
Abstract The clay minerals kaolin, smectite and palygorskite-sepiolite are among the world's most important and useful industrial minerals. Clay minerals are important in a number of geological applications such as stratigraphic correlations, indicators of environments of deposition and temperature for generation of h…
Chemically vapor deposited silicon carbide (CVD SiC) was oxidized at temperatures of 1000°‐1400°C in H 2 O/O 2 gas mixtures with compositions of 10‐90 vol% water vapor at a total pressure of 1 atm. Additional experiments were conducted in H 2 O/argon mixtures at a temperature of 1100°C. Experiments were designed to mi…
Basic correlations between polymer morphology, silicate superstructures, glass temperature, stiffness and toughness of thermoset nanocomposites were investigated as a function of layered silicate type and content. The nanocomposites were based upon hexahydrophthalic anhydride-cured bisphenol A diglycidyl ether and lay…
Communication: Dendrimers act as templates for platinum nanoparticles. The authors describe a general synthetic approach whereby a dendrimer nanotemplate is loaded with Pt2+, which is reduced in situ to yield a dendrimer-encapsulated metal cluster. The clusters are monodisperse and very stable, and when attached to an…
The adsorption of model proteins onto brush-coated surfaces can occur via two modes. Primary adsorption at the surface, where short range attraction is dominant, is important for small proteins and may be repressed by increasing the grafting density. Secondary adsorption, due to van der Waals attraction, occurs at the…
Full-matrix least squares is taken as the basis for an examination of protein structure precision. A two-atom protein model is used to compare the precisions of unrestrained and restrained refinements. In this model, restrained refinement determines a bond length which is the weighted mean of the unrestrained diffract…
Abstract The origin and formation of soil clay minerals, namely micas, vermiculites, smectites, chlorites and interlayered minerals, interstratified minerals and kaolin minerals, are broadly reviewed in the context of research over the past half century. In particular, the pioneer overviews of Millot, Pedro and Duchau…
Saturation effects are determined in x-ray magnetic circular dichroism spectra, acquired by electron yield techniques. It is shown that sum-rule extraction of the number of d holes, orbital moment, and spin moment are affected for Fe, Co, and Ni. In particular, errors in the extracted orbital moment values due to satu…
We studied the shape transformation (by use of TEM and optical absorption spectroscopy) of gold nanorods in micellar solution by exposure to laser pulses of different pulse width (100 fs and 7 ns) and different energies (μJ to mJ) at 800 nm, where the longitudinal surface plasmon oscillation of the nanorods absorb. At…
We present a method for atomic-scale modeling of the magnetic behavior of ionic magnetic solids. Spin distributions and net magnetic moments are calculated for nanoparticles of ferrimagnetic ${\mathrm{NiFe}}_{2}{\mathrm{O}}_{4}$ and $\ensuremath{\gamma}\ensuremath{-}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3},$ and antiferromag…
High-quality ZnO films are receiving increased interest for use in low-loss high-frequency surface acoustic wave (SAW) devices, acousto-optic and optical modulators, as buffer layers for III-nitride growth, and as the active material in ultraviolet solid state lasers. In this work, high quality epitaxial ZnO films wer…
The origin and dispersion of the anomalous disorder-induced Raman band $(D$ band) observed in all ${\mathrm{sp}}^{2}$ hybridized disordered carbon materials near 1350 ${\mathrm{cm}}^{\ensuremath{-}1}$ is investigated as a function of incident laser energy. This effect is explained in terms of the coupling between elec…
The development of varistor ceramics is reviewed with an emphasis on ZnO‐based varistors formed by liquid‐phase sintering. Particular attention is given to the effects of microstructural disorder on the properties of varistors and to the different modes of failure that can occur.
Poly(3-hydroxyalkanoates) (PHAs) are a class of microbially produced polyesters that have potential applications as conventional plastics, specifically thermoplastic elastomers. A wealth of biological diversity in PHA formation exists, with at least 100 different PHA constituents and at least five different dedicated…
Mixed-valence manganese oxides (R1-χAχ)MnO3 (R=rare-earth cation, A=alkali or alkaline earth cation), with a structure similar to that of perovskite CaTiO3, exhibit a rich variety of crystallographic, electronic and magnetic phases. Historically they led to the formulation of new physical concepts such as double excha…
Nanophase TiO 2 was prepared by a stearic acid sol–gel technique. X-ray measurements showed that the as-prepared sample is anatase TiO 2 phase with an average grain size of 10.4 nm. Raman spectroscopy was used to investigate the structural transformation from anatase-to-rutile in the nanophase TiO 2 annealed at a seri…
The review surveys data on over 200 crystal and molecular structures of metal halide complexes with oxygen-containing crown ethers. The major types of the complexes are distinguished. The characteristic features of formation of these complexes and their coordination fragments are discussed. The bibliography includes 1…