Materials Literature
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We compare time-dependent solutions of different phase-field models for dendritic solidification in two dimensions, including a thermodynamically consistent model and several ad hoc models. The results are identical when the phase-field equations are operating in their appropriate sharp interface limit. The long time…
In this work, the many-spin interactions taking place in ${\mathrm{Mn}}_{12}$ large-spin clusters are extensively studied using the 8-spin model Hamiltonian, for which we determine the possible parameters based on experimental data. Account of the many-spin excitations satisfactorily explains positions of the neutron…
Nanocrystalline cerium(IV) oxide (CeO 2 ) powders were prepared by heating solutions of cerium(IV) salts in the presence of urea under hydrothermal conditions at 120° to 180°C. The effects of the concentration of urea and hydrothermal treatment temperature on the morphology and crystallite size of the synthesized part…
Abstract The construction and operation of a spray drier is described where the spray is produced using an air brush, essentially a miniature spray gun. The spray-dried products consist of spheres 50–60 µm in diameter and typical product recoveries are 80%, a marked improvement over simple two-nozzle systems. The spra…
The formation and decay of the optical hole (bleach) for 4 nm CdSe nanoparticles (NPs) with adsorbed electron acceptors (1,4-benzoquinone and 1,2-naphthoquinone) and the rise and decay of the reduced electron acceptors formed after interfacial electron transfer from the CdSe NPs were investigated by femtosecond laser…
We study the emission line shapes of single CdSe nanocrystallite quantum dots. Single dot line shapes are found to result from rapid spectral shifting of the emission spectrum rather than the intrinsic physics of the quantum dot. A strong dependence of single dot line widths on excitation intensity, wavelength, temper…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTUnusual Kinetic Stability of a Ground-State Singlet Oxomanganese(V) Porphyrin. Evidence for a Spin State Crossing EffectNing Jin and John T. GrovesView Author Information Department of Chemistry, Princeton University Princeton, New Jersey 08544 Cite this: J. Am. Chem.…
The electropolymerization of different azines from aqueous solutions was investigated. The structure of monomers was systematically varied changing both the nature of the second heteroatom and the substituents in the aromatic rings. Considering the electropolymerization process and the properties of the resulting poly…
Communication: The brightness and efficiency of liquid crystal displayscan be improved by replacing the second polarizer and color filter with a single oriented polyethylene film containing monodisperse silver nanoparticles, as revealed in the Figure. The preparation of the films, which exhibit bright colors and appea…
We report a novel method for the synthesis of stable, OH free zinc oxide quantum dots, using an electrochemical route. The optical properties of these quantum dots were studied at room temperature, by taking the optical absorption and luminescence spectra. The band gap luminescence is predominant in ZnO quantum dots s…
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…