Materials Literature
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Photoluminescence study using the 325 nm He-Cd excitation is reported for the Au nanoclusters embedded in SiO2 matrix. Au clusters are grown by ion beam mixing with 100 KeV Ar+ irradiation on Au [40 nm]/SiO2 at various fluences and subsequent annealing at high temperature. The blue bands above ~3 eV match closely with…
Gutsy chemistry: A solvothermal process has been developed for the controlled creation of interior space in TiO2 intestines (either hollow (see TEM image) or partially filled) or spheres in the anatase polymorph. A morphological transformation from intestine to sphere is observed when the water content of the water/2-…
A bicontinuous cubic structure was revealed by electron crystallography on a large-pore mesoporous silica with a cubic Iad symmetry synthesized by using a triblock copolymer as a structure-directing agent. Its reconstructed structure (picture, left) is composed of an enantiomeric pair of interwoven three-dimensional m…
We report the results of a model calculation for studying the effects of hydrostatic pressure on a bunch of carbon nanotubes. At pressures that we work with, the deformation in axial direction comes out to be negligibly small. We find that hydrostatic pressure is an ideal probe to study the radial deformations of the…
If metal surfaces are exposed to sufficiently oxygen-rich environments, oxides start to form. Important steps in this process are the dissociative adsorption of oxygen at the surface, the incorporation of O atoms into the surface, the formation of a thin oxidic overlayer and the growth of the once formed oxide film. F…
Charge and orbital ordering in the low-temperature monoclinic structure of magnetite (Fe3O4) is investigated using the local spin density approximation with Coulomb interaction correction method. While the difference between t(2g) minority occupancies of Fe(2+)(B) and Fe(3+)(B) cations is large and gives direct eviden…
The electrospinning process was used successfully to embed single-walled carbon nanotubes (SWCNTs) in a poly(ethylene oxide) (PEO) matrix, forming composite nanofibers. Initial dispersion of SWCNTs in water was achieved by the use of an amphiphilic alternating copolymer of styrene and sodium maleate. The resulting dis…
Dry films: An electrospinning process was used to form films with high water contact angles (166.7°) and low sliding-angles (4.3°). The electrospun films exhibit excellent superhydrophobic Cassie-regime stability: The figure shows a nonwetting water droplet, even after 400 Pa of uniaxial loading.
Spider silk proteins have mainly been investigated with regard to their contribution to mechanical properties of the silk thread. However, little is known about the molecular mechanisms of silk assembly. As a first step toward characterizing this process, we aimed to identify primary structure elements of the garden s…
Solution-phase synthesis of single-crystal ZnO disks and rings was achieved in high yield at low temperature (70–90 °C) by using an anionic surfactant as a template. The reaction can be controlled by means of the growth temperature and the molar ratio of reagents to favor formation of disks or rings. A growth mechanis…
This Letter reports the laser energy dependence of the Stokes and anti-Stokes Raman spectra of carbon nanotubes dispersed in aqueous solution and within solid bundles, in the energy range 1.52--2.71 eV. The electronic transition energies (${E}_{ii}$) and the radial breathing mode frequencies (${\ensuremath{\omega}}_{\…
Highly c-axis oriented CaRuO3 thin films were prepared on LaAlO3 buffered Si(100) substrates at 650 °C by pulsed laser deposition. The buffer layer had a significant effect on the microstructure and electrical properties of the subsequent CaRuO3 thin films. Typical columnar grown CaRuO3 films were available using LaAl…
We study Nim with the additional rule that each player can put a constraint on the next player’s move. This is called a Muller twist. The constraints are of the form “the number taken must not be equivalent to some numbers modulo n”. A solution for a large group of such games is given.
Most prediction methods for wave overtopping are based on physical model tests under simple 2-D conditions. This paper describes experiments to measure mean and wave-by-wave overtopping discharge under oblique wave attack. Results suggest that overtopping discharges reduce significantly only for angles of wave attack…
Rigid pour polyurethane foam is presented to serve as a high voltage insulation material. The proposed foam is closed-cell two components flotation system that has low viscosity and low pressure. Different production techniques are applied and explained. The investigation of cross-section and skin of rigid pour polyur…
The presence of pollution on the insulators surfaces considerably modifies the voltage distribution across an insulator string. This phenomenon has been studied and a computer program has been developed. Poor design, manufacturing defects and pollution can caused flashover (voltage which will cause an arc through the…
Magnetismus mit neuem Dreh: Der chirale 3D-Ferrimagnet [{CrIII(CN)6}{MnII(d- oder L-NH2ala)}3]⋅3 H2O (NH2ala=Aminoalanin-Ion) mit Tc=35 K ist durch eine ausgedehnte, chirale, tripelhelicale Anordnung von MnII-Ionen gekennzeichnet, die durch die Koordination der organischen Liganden verursacht wird (siehe Bild; violett…
The existence of low angular momentum image-potential states is predicted both for single- and multiwalled nanotubes. The states are confined between the self-induced potential on the vacuum side and the surface barrier, created by the central ascent in the transverse nanotube potential. Effective interactions near th…
The optical and electronic properties of a wide-gap (∼3.3 eV) layered oxychalcogenide, La 2 CdO 2 Se 2, were examined using epitaxial thin films prepared by a reactive solid-phase epitaxy. Two optical absorption peaks due to exciton split by the spin−orbit interaction were observed at 3.43 and 3.61 eV at 10 K near the…
Electrical and optical properties of poly(3-methylthiophene) (P3MeT) films have been studied by the current-sensing atomic force microscopic (CS-AFM) and near-normal incidence reflectance spectroscopic (NNIRS) techniques. The P3MeT films were electrochemically deposited onto gold-on-silicon electrodes and their doping…