Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
A new model of line-profile broadening due to the effect of linear and planar lattice defects has been incorporated into the conventional Rietveld algorithm for the structural refinement and whole-pattern fitting of powder data. The proposed procedure, applied to face-centred cubic (f.c.c.) structure materials, permit…
We study the biaxial structure of both line and point defects in a nematic liquid crystal confined within a capillary tube whose lateral boundary enforces homeotropic anchoring. According to Landau-de Gennes theory the local order in the material is described by a second-order tensor Q, which encompasses both uniaxial…
The electrical transport properties of grain boundaries in the epitaxial La 2/3 Ca 1/3 MnO 3 − δ thin films have been studied as a function of temperature and applied magnetic field. Below the Curie temperature T C an additional grain boundary resistance, highly non-linear current-voltage curves, and a large magnetore…
Crustacean chitins and fungal chitin–glucan complexes are subjected to regiospecific oxidation at C-6 with NaOCl in the presence of Tempo® and NaBr at 25°C in aqueous solution. The resulting products have anionic character and are fully soluble over the entire pH range; they lend themselves to metal chelation, polyele…
In inactive glasses used as models for French nuclear waste forms, Zr K ‐ and L 2,3 ‐edge X‐ray absorption spectroscopy spectra indicate that Zr is only 6‐coordinated, with d (Zr‐O) distances of 2.08 ± 0.01 Å and with a small radial disorder. Beyond, the first coordination shell, next‐nearest Si neighbors occur at abo…
Stoichiometric zinc ferrite fine powders showing long-range magnetic order to temperatures above 30 K have been prepared by the supercritical sol-gel method. The low-temperature magnetic behavior of the as-produced powder, and portions calcined at 500 and 800 \ifmmode^\circ\else\textdegree\fi{}C, were determined by M\…
A European consortium is evaluating materials for the construction of a new supersonic transport aircraft that may replace Concorde. Current designs propose to use an aluminium alloy for the fuselage which is required to have superior creep resistance and damage tolerance to the Concorde alloy 2618A. Promising results…
We analyze the thermodynamics of disklike particles dispersed in a polymer matrix. Using the Somoza−Tarazona free energy functional for thin oblate ellipsoids of revolution in combination with the Flory−Huggins mixing free energy, we obtain a new expression that allows us to describe the complete (liquid, crystalline,…
We have studied singlet electronic energy transfer (EET) in two donor−bridge−acceptor series (D−B−A), in which the donor (zinc porphyrin or its pyridine complex) and the acceptor (free base porphyrin) were covalently connected by a geometrically well-defined bridging chromophore. We have investigated how the medium be…
Yttrium aluminum garnet (YAG) precursors for transparent ceramics were synthesized by the urea method under various [urea]/[metal ions] ([U]/[M]) conditions. Monophase YAG was obtained from solutions with a high [U]/[M] ratio after calcination at a temperature of 1200°C. The condition of the precipitates seemed to ind…
It has been proved that surfactant−silicate supramolecular architecture formed on a silicon substrate is strongly affected by the crystal orientation of a silicon wafer, indicating the variation of the interactions between the surfactants and the silicon surfaces. The hexagonal mesoporous silica film with aligned meso…
We report results from molecular simulations of binary aqueous solutions of the carbohydrate stereoisomers, β- d -glucose, β- d -mannose, and d -fructose over a concentration range from zero to 80 wt % carbohydrate at 300 and 270 K. It is found that increasing carbohydrate concentration has a number of striking effect…
Polyaniline-coated steel panels were studied by electrochemical impedance spectroscopy (EIS) and electrochemical noise methods (ENM). EIS data for the polyaniline sample was obtained for increasing time of immersion. An increase in charge-transfer resistance (Rct) with immersion time was observed. ENM data showed that…
High surface area conducting polymers with nanoscale dimensions are an important aim for device applications. Here is reported the polymerization and electrochemical oxidation of aniline at multiwalled carbon nanotube electrodes. Polyaniline films formed on these nanotube whiskers are oxidized more easily and produce…
An analysis of polycrystalline Au thin film interconnects of widths ranging from 850 to 25 nm, and lengths ranging from 1.0 μm to 20 nm which have been electrically stressed to the point of failure is presented. For the longer wires (widths 60–850 nm), the failure current density is typically found to be 1012 A m−2, e…
We have characterized the gene encoding fatty acid alpha-hydroxylase, a cytochrome P450 (P450) enzyme, from Sphingomonas paucimobilis. A database homology search indicated that the deduced amino acid sequence of this gene product was 44% identical to that of the ybdT gene product that is a 48 kDa protein of unknown fu…
▪ Abstract Combinatorial materials synthesis methods and high throughput evaluation techniques have been developed to accelerate the process of materials discovery and optimization. Analogous to integrated circuit chips, integrated materials chips containing thousands, possibly millions, of different compounds/materia…
We calculate the conductance of a circular constriction of radius a in an insulating diaphragm which separates two conducting half spaces characterized by the mean free path l. Using the Boltzmann equation we obtain an answer for all values of the ratio $l/a.$ Our exact result interpolates between the Maxwell conducta…
Thermally initiated cationic ring-opening polymerization of 3-ethyl-3-(hydroxymethyl)oxetane was carried out using benzyltetramethylenesulfonium hexafluoroantimonate as initiator. The resulting hydroxy-functional polyether was thoroughly analyzed by 1H and 13C NMR spectroscopy and found to have a hyperbranched archite…
Currently, the immunohistochemical evaluation of smooth muscle differentiation is usually based on desmin, which also reacts with skeletal muscle and is not present in all smooth muscle tumors, and alpha-smooth muscle actin, which reacts with myoepithelial cells. Neither marker typically reacts with gastrointestinal s…