Materials Literature
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Abstract Individual but connected synthetic routes for the preparation of the all‐E ‐configured 2,5‐dipropoxy‐substituted oligo(1,4‐phenyleneethenylene)s 1a–g were developed. An increasing number of conjugated stilbene units from n = 1 to n = 11 led to a convergent bathochromic shift (Δλ = λ ∞ − λ 1 = 127 nm) in the U…
We report on the application, for the first time to our knowledge, of spectroscopic generalized ellipsometry to liquid crystal materials. We have measured the three normalized elements of the Jones transmission matrix t at various sample temperatures within the spectral range from 340 to 1700 nm (0.73 to 3.65 eV) on t…
In order to identify the origin of dielectric relaxation of Pt/Ba 1- x Sr x TiO 3 /Pt thin-film capacitors, effects of post-annealing in oxygen ambient on their electrical properties were investigated. From comparison of the electrical properties of as-deposited and post-annealed capacitors, it is concluded that elect…
Grazing-incidence specular and diffuse X-ray scattering has been performed on polished surfaces of the glass ceramic Zerodur (registered trademark of Schott Glaswerke, Mainz). Analysis using a distorted-wave Born approximation showed that satisfactory fits to the data could be obtained only if grading was included at…
The energies and dispersions of the image states and quantum well electronic states in layers of Xe and Kr on a Ag(111) substrate were determined by angle-resolved two-photon photoemission (ARTPPE). For Xe, we measured binding energies of unoccupied electronic states for 1–9 layers and their parallel dispersion out to…
The hydrogen storage properties of a novel Mg 2 Ni alloy powder prepared with a mechanical grinding method were investigated. This alloy powder was transformed to an amorphous‐like state by this treatment. As a result, an electrode of this alloy shows a large discharge capacity (750 mAh/g) which is 2.5 times higher th…
A new model is presented for the gas dynamics within a bubble at conditions that lead to the phenomenon of sonoluminescence. The spherically symmetric Navier–Stokes equations with variable properties are solved together with momentum and energy equations in the liquid. Calculations are presented for bubbles of argon,…
An effective electronic Hamiltonian for transition-metal oxide compounds is presented. For Mn oxides, the Hamiltonian contains spin-2 "spins" and spin-$\frac{3}{2}$ "holes" as degrees of freedom. The model is constructed from the Kondo-lattice Hamiltonian for mobile ${e}_{g}$ electrons and localized ${t}_{2g}$ spins,…
Polarization charges, which are assumed to be located on crystal surfaces and contribute to ultra low frequency dielectric relaxation, were investigated through thermally stimulated current (TSC) studies of perovskite titanates in both single crystal and polycrystalline forms. When the anodic sides of the poled single…
For several years, the polyurethanes industry has critically examined its products in order to meet all present, and possible future, US environmental regulations. Formulations have had to be adapted to new types of blowing agents in order to compare favourably with the thermal and fire performances previously achieve…
A detailed electrical investigation of oxidized porous silicon (OPS) has been undertaken, using metal oxide semiconductor capacitors. We demonstrate that the dielectric can provide good electrical isolation under moderate electric fields, exhibiting low leakage current, high resistivity, reasonably low interface state…
Abstract Crystals of the orthorhombic phase of strontium germanate showing superstructure have been obtained. Crystal data are: a = 5.8520(4) Å, b = 14.2991(8) Å, c = 9.9165(6) Å, space group Pbn 2 1 and Z = 8 × Sr 2 GeO 4 . The structure has been determined based on a set of 3567 diffraction intensities measured with…
Abstract Scintillation in cerium‐doped gadolinium‐based crystals results from the energy transfer of excited host matrix Gd 3+ ions ( 6 I 7/2,11/2 ; 6 P 7/2,5/2) to the Ce 3+ ions {5d 1 ( 2 T 2 )} which radiatively relax to the ground state.
Abstract A novel biodegradable polyester having pendant amine functional groups was snythesized from N ‐(benzyloxycarbonyl)‐ L ‐aspartic anhydride ( 2 ) and 1,4‐cyclohexanedimethanol ( 3 ) by polycondensation reaction using p‐toluenesulfonic acid as a catalyst. The synthesized polymer 4 shows the characteristic ester…
Abstract Weathering performance of rigid PVC pigmented with iron oxide or some complex inorganic pigments (CIP) containing iron can be poor. Consideration of iron‐containing CIP's for use in exterior PVC leads to the common question: “How much ‘free iron’ is present in the pigment?” It has been unclear what “free iron…
Abstract The effective second harmonic generation coefficient of monomethyl urea has been determined relatively to urea by phase matched interaction. Both Type I and Type II phase matching have been achieved by propagating the pump beam at small angles to natural faces of solution grown crystals. The conversion effici…
Three-dimensional images of the near-surface atom arrangement were calculated from two-dimensional photoelectron diffraction data by several imaging algorithms: (i) a basic method with a Fourier transformation at one kinetic energy over k space, considering the phase factor due to the path-length difference; (ii) ener…
Corrosive exposure and subsequent deterioration of weathering steel structures cause strength loss due to cross-section thinning as well as crack susceptibility due to formation of notches that concentrate stresses. Key issues include rapidly drying versus extended wet time surfaces, the relationship of clean versus d…
Les evolutions microstructurales de l’alliage de titane β-Cez au cours de son forgeage β ont ete suivies par des essais de compression uniaxiale sur une large gamme de vitesse [10-3 -10 s-1 ] et de deformation [0,25,1,5]. L’examen des textures (RX), des structures, des microtextures (EBSD) ainsi que le trace de cartes…
Abstract The oxidative degradation of benzo nuclei of various higher contropolyindanes with ruthenium (VIII) oxide or ozone was studied to further explore the chemistry of partially benzoanellated centrohexaquinanes. Besides the two tribenzotri‐quinacenes 12 and 15 which were used as model substrates for oxidation wit…