Materials Literature
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The time-convolutionless master equation for the electronic populations is derived for a generic electron-phonon Hamiltonian. The equation can be used in the regimes where the golden rule approach is not applicable. The equation is applied to study the electronic relaxation in several models with the finite number of…
By employing the analytic embedded-atom potentials of Mei {\it et al.} [Phys. Rev. B 43, 4653 (1991)] we have calculated the phonon dispersion spectra for six fcc metals: Cu, Ag, Au, Ni, Pd and Pt. We have also investigated thermal properties of these metals within the quasiharmonic approximation. Results for the latt…
In this review, we hope to give the reader a self-contained contemporary presentation of the application of Landau theory to ferroelectrics. We begin by developing Landau theory for homogenous bulk ferroelectrics and then consider the finite-size (thin film) case within the related Landau-Ginzburg approach. Next we di…
We address the quality of electrical contact between carbon nanotubes and metallic electrodes by performing first-principles calculations for the electron transmission through ideal 2- and 3-terminal junctions, thus revealing the physical limit of tube-metal conduction. The structural model constructed involves surrou…
A hybrid white-light-emitting device (see figure) whose emission originates only from ternary nanocrystal (quantum dot) composites but whose luminance performance matches the requirements of the lighting industry is demonstrated. The bright white-light emission is obtained by controlling the Förster energy transfer an…
Nacre is a natural nanocomposite material with superior mechanical strength and toughness. What roles do the nanoscale structures play in the inelasticity and toughening of nacre? Can we learn from this to produce nacre-like nanocomposites? Here we report in situ dynamic atomic force microscope observations of nacre w…
An investigation is reported on the interfacial properties of nanometric colloidal silica dispersions in the presence of a cationic surfactant. These properties are the result of different phenomena such as the particle attachment at the interface and the surfactant adsorption at the liquid and at the particle interfa…
Regular gold nanodecahedra (pentagonal bipyramids) are obtained in high yield through ultrasound-induced reduction of HAuCl4 by dimethylformamide on presynthesized seeds (see figure). A dependence of the final morphology on the crystalline structure of the seeds is demonstrated by growing gold on single-crystal platin…
Superhydrophobic surfaces, with a liquid contact angle theta greater than 150 degrees , have important practical applications ranging from self-cleaning window glasses, paints, and fabrics to low-friction surfaces. Many biological surfaces, such as the lotus leaf, have a hierarchically structured surface roughness whi…
Biocompatible Fe3O4 magnetic nanocrystals with reactive moieties on the surface can be prepared via a “one-pot” reaction and used straightforwardly in cancer detection by being coupled with a specific cancer-targeting antibody. It is demonstrated that the as-prepared Fe3O4 nanocrystals can potentially be used as effec…
The electronegativities of 82 elements in different valence states and with the most common coordination numbers have been quantitatively calculated on the basis of an effective ionic potential defined by the ionization energy and ionic radius. It is found that for a given cation, the electronegativity increases with…
Supercapacitor electrode materials must exhibit high specific capacitance and high-rate charge–discharge ability. The ordered whiskerlike polyaniline (PANI) reported here, which was synthesized in situ on the surface of mesoporous carbon by a novel process, is demonstrated to have these properties thanks to its ordere…
Scherenschnitt: Die Analyse der kristallographischen Scherstrukturen von „Pb2Fe2O5“ (siehe Bild; Pb-Kugeln und FeO6/FeO5-Polyeder) zeigte neue Aufbauprinzipien für Perovskite, die A-Kationen mit einem freien Elektronenpaar enthalten. Die chemische Zusammensetzung kann über die Orientierung der Scherebenen und die Dick…
Abstract A series of CdSe submicrostructures, including rods, fringy structures, and fasciculate tubes with high hierarchy, have been selectively prepared by a facile one‐step solution‐based strategy without using any organic surfactants, simply by changing the feeding quantity of aqueous ammonia (25 % NH 3 ). The gro…
The crystal and molecular structures of two novel derivatives of the lophine chromophore with different solvents of crystallization are presented and discussed. Phenol, 2-[4,5-bis(4-methoxyphenyl)-1 H -imidazole-2-yl]-4-nitro ( 1 ) and phenol, 2-[4,5-bis(4-methyl-phenyl)-1 H -imidazole-2-yl]-4-nitro ( 2 ) form inclusi…
Pseudomonas sp. 14-3 accumulates polyhydroxybutyrate (PHB) from octanoate, but not from glucose. To elucidate this unusual phenotype, genes responsible for the synthesis of PHB were cloned and analyzed. A PHB polymerase gene (phaC) was found downstream from genes coding for a beta-ketothiolase (phaA), an acetoacetyl-c…
Electrochemical studies of thiol-capped ZnSe nanocrystals in aqueous solution have demonstrated several distinct oxidation and reduction peaks in the voltammograms, with the peak positions being dependent on the size of the nanocrystals and their photoluminescence quantum efficiency. The evolution of the specific feat…
The EPR spectra of radical surfactant probes embedded in cetyltrimethylammonium bromide (CTAB) and trimethylbenzene (TMB) stable water emulsions (TMB/CTAB = 13) were analyzed to provide information on the kinetics of formation of micelle-templated silicoaluminas (MTSA) at 343 K, obtained by means of silica and alumina…
Amoxicillin is an important semi-synthetic antibiotic produced in large quantities around the world, and developing a highly cost-effective crystallization process for amoxicillin is of significant importance. In this study an in situ turbidity meter is used to measure the induction period for the onset of nucleation…
We report on the preparation of supported columnar CeO(2) nanostructures by a simple catalyst-free chemical vapor deposition process at temperatures as low as 623 K. A suitable choice of experimental parameters enables us to control the structural and morphological features of the resulting ceria nanosystems.