Materials Literature
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Polarization holographic gratings were inscribed in azobenzene side chain polymer films. The polarization gratings were produced using two orthogonally circularly polarized beams and the resulting stable transmission gratings were studied using a low power HeNe laser. The gratings were observed to efficiently separate…
Steric interactions between the anthraquinoid core and the 1,3-dithiole and dicyanomethylene groups play a key role in determining the physical properties of system 1. The intramolecular charge transfer properties of this donor–π-acceptor species have been explored and cyclic voltammetric data, X-ray crystal structure…
Zeitabhängige NMR- und MS-Analysen ergaben, daß bei der Selbstorganisation eines linearen Liganden mit Metallionen mit oktaedrischer Koordinationsgeometrie wie Fe2+ oder Ni2+ zuerst unter kinetischer Kontrolle Dreifachhelicate und anschließend die thermodynamisch stabileren ringförmigen Helicate 1 entstehen. Die Ergeb…
The misfolding process of the amyloidogenic proteins such as prion proteins is mimicked by the α- to β-structural transition of a peptide obtained by introducing adamantanecarbonyl groups at the N-terminals of two linked α-helices. The α- to β-transition (left to right of graph) coincided with the formation of fibrils…
] with an unoccupied Ag position (right in picture)-both hitherto unknown-are found in two new layer-type double salts of AgCN and AgF that display novel types of cyanide coordination modes.
The photophysical properties of wire-type compounds based on a photosensitizing RuII complex linked to an electron-accepting bipyridinium or diazapyrenium group have been studied with the aim of designing light-driven molecular machines based on pseudorotaxanes (shown schematically). As an outcome, the photoinduced de…
A family of smectic liquid-crystalline dendrimers has been synthesized by connecting rodlike cyanobiphenyl mesogens, with various spacer lengths, at the periphery of poly(propylene imine) dendrimers. A combination of differential scanning calorimetry, optical microscopy, and X-ray diffraction suggests that, under the…
Hybrid colloids with new and unusual morphologies (see figure) are formed by precipitation of calcium phosphates in the presence of hydrophobically modified double-hydrophilic block copolymer micelles. The use of interactive polymer templates broadens the toolbox of chemistry required for the construction of complex s…
We have studied the effect of disorder on the radiative properties of semiconductor quantum wires by time-resolved photoluminescence spectroscopy. The dependence of the radiative lifetimes is measured over a temperature range extending from 8 to 150 K. At low temperatures we find that the measured dependence does not…
An ab initio LMTO approach and semi-empirical quantum chemical INDO method have been used for supercell calculations of basic point defects - F-type centers and hole polarons bound to cation vacancy - in partly covalent perovskite KNbO3. We predict the existence of both one-site and two-site (molecular) polarons with…
The effective transport coefficients and figure of merit ZT for anisotropic systems are derived from a macroscopic formalism. The full tensorial structure of the transport coefficients and the effect of the sample boundaries are included. Induced transverse fields develop which can be larger than the applied fields an…
We demonstrate theoretically that the electronic ground state of the potassium-covered Si(111)-B surface is a Mott insulator, explicitly contradicting band theory but in good agreement with recent experiments. We determine the physical structure by standard density-functional methods, and obtain the electronic ground…
The Jahn-Teller effect used semi-theoretically to analyse UV-visible spectra of the diamond like-carbon films on Si substrates. By deconvolution of UV-visible absorption spectra of the typical films, different absorption lines found. For each sample, six lines which were related to $\V^\circ$ by Jahn-Teller effect are…
Nickel and Rhodium (001) surfaces display a similar - as from STM images - clock reconstruction when half a monolayer of C/Ni, N/Ni or O/Rh is adsorbed; no reconstruction is observed instead for O/Ni. Adsorbate atoms sit at the center of the black squares of a chess-board, $c(2\times 2)$, pattern and two different rec…
We investigate collective dissipative properties of vibrated granular materials by means of molecular dynamics simulations. Rates of energy losses indicate three different regimes or "phases"in the amplitude-frequency plane of the external forcing, namely, solid, convective, and gas-like regimes. The behavior of effec…
Ab-initio results for structural and electronic properties of NaCl-type FeN are presented in a framework of plane-wave and ultrasoft pseudopotentials. Competition among different magnetic ordering is examined. We find the ferromagnetic phase stable overall. Stabilization over the unpolarized phase is obtained by split…
We study theoretically the collective orbital excitation named orbital wave in the orbital ordered manganites.The dispersion relation of the orbital wave is affected by the static spin structure through the coupling between spin and orbital degrees of freedom. As a probe to detect the dispersion relation, we propose t…
We present a set of molecular dynamics (MD) simulations of strongly charged, flexible polyelectrolyte chains under poor solvent conditions in a salt free solution. Structural properties of the chains and of the solutions are reported. By varying the polymer density and the electrostatic interaction strength we study t…
Abstract Cast irons primarily are iron alloys that contain more than 2% carbon and from 1 to 3% silicon. This article provides a description of iron-iron carbide-silicon system; and discusses the classification, composition, and characteristics of cast irons, such as gray, ductile, malleable, compacted graphite, and w…
Temperature dependence of the principal refractive indices (n 0 and ne ) of three nematic liquid crystals were measured using an Abbe refractometer with a large refractive index prism. The variation of the refractive index anisotropy in the nematic phase which reflects the variation of the orientational order paramete…