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。
Experimental measurements of the viscosity of silica (SiO2) are critically examined; the best measurements show an activation energy of 515 kJ/mole above 1400 °C and 720 kJ/mole below this temperature. The diffusion of silicon and oxygen in silica have temperature dependencies close to that of the high temperature vis…
Carbon nanotubes were discovered in 1991. It was soon recognized that layered metal dichalcogenides such as MoS2 could also form fullerene and nanotube type structures, and the first synthesis was reported in 1992. Since then, a large number of layered chalcogenides and other materials have been shown to form nanotube…
Easily accessible [(salen)(iPrO)Al] exerts excellent molecular-weight and stereochemical control in lactide polymerization either in solution or in the absence of solvent. The R,R initiator shows a marked preference for L-lactide over D-lactide. Stereoblock copolylactides (see scheme) with high melting points can be p…
Correlation consistent basis sets for accurately describing core–core and core–valence correlation effects in atoms and molecules have been developed for the second row atoms Al–Ar. Two different optimization strategies were investigated, which led to two families of core–valence basis sets when the optimized function…
Article Anwendung der Rasterelektronenmikroskopie und der Transmissionselektronenmikroskopie in der Halbleiterindustrie / Application of Scanning Electron Microscopy and Transmission Electron Microscopy in Semiconductor Industry was published on December 1, 2002 in the journal Practical Metallography (volume 39, issue…
Gradient-index lenses are samples whose special characteristics must be taken into account to design the optical polariscopes that can be applied in the evaluation of their birefringence. We discuss the main infidelity sources that modify the conoscopic patterns when a traditional polariscopic setup is used.
We report the XPS spectra of sodium phosphate. XPS spectra were collected with a VSW HA150 x-ray photoelectron spectrometer using monochromatic Al Kα x-radiation. Monochromatic radiation provides a distinct clarity to the rich peak structure in the valence band of sodium phosphate due to the absence of interfering x-r…
Abstract Poly( p -xylylene)s (PPX) with aliphatic substituents at the alpha position were synthesized by chemical vapor deposition (CVD) via vapor phase pyrolysis of α-chloro-1,4-xylenes, or by base-induced dehydrohalogenation of α-chloro-1,4- xylenes (Gilch route). These PPXs are soluble under ambient conditions in o…
Abstract A new type of tetraimide‐dicarboxylic acid (I) was synthesized starting from the ring‐opening addition of m ‐aminobenzoic acid ( m ‐ABA), 4,4′‐oxydiphthalic anhydride (ODPA) and 4,4′‐methylenedianiline (MDA) at a 2:2:1 molar ratio in N ‐methyl‐2‐pyrrolidone (NMP), followed by cyclodehydration to the diacid I.…
This paper describes a novel experimental approach to assessing fabric structural geometry under compression, and presents a study of some typical technical fabrics. The method employs a "stress-freezing" technique, where a fabric sample, impregnated with a clear resin, is subjected to compressive stress and held unde…
A nematic liquid crystal can be converted into a cholesteric phase by a chiral dopant, and the cholesteric pitch can be changed by its photochemical transformations [1]. For the first time we investigate the dynamics of the cholesteric phase induction using seven steroids (vitamin D isomers and related compounds) as c…
Pseudo-poly(amino acids) are synthetic biodegradable polymers made from natural metabolites. The use of natural metabolites for the synthesis of biomedical materials originated from the concern about the possible toxicity of the degradation products of biodegradable materials. Here we present the surface characterizat…
A model has been proposed to calculate the thermal conductivity of composite made from parallel fibres aligned at an angle to the heat flow direction. The model after verification has been modified for a twisted fibre assembly. From the modified model, the longitudinal thermal conductivity values of fibres are calcula…
Abstract Modification of the interface changes the viscoelastic response of crystalline polymer blends. For incompatible systems, usually one or more additional tan δ (mechanical loss) peaks appear which reflect the embrittlement of the material. Upon proper compatibilization, the additional peaks disappear and the ma…
The reasons for anomalous growth in the thermopower of metal borides at high temperatures is analyzed. It is shown that this behavior of thermopower cannot be explained within the present models of charge transfer in disordered semiconductors. The anomalous growth of thermopower in polar materials can be interpreted b…
Abstract The problem of galvanic coupling of mild steel to carbon fibres in aqueous solutions relevant to environmental exposure cases is attacked in this research. Acid sulphate and near neutral chloride and bicarbonate solutions are considered. The application background of this investigation is the mechanical joini…
The Rietveld method can be combined with the addition method to determine the absolute quantities of the phases treated by Rietveld refinement plus the quantity of phase(s) not treated by it (amorphous or unobserved). If q is the added proportion of a defined phase already present in the sample, and a 1 and a 2 its re…
Article Redetermination of the crystal structure of potassium trans-(dioxo) tetra(hydroxo)osmate(VI), K2[Os(OH)4(O)2] was published on December 1, 2002 in the journal Zeitschrift für Kristallographie - New Crystal Structures (volume 217, issue JG).
A dense, bulk ceramic of Ti3SiC2 containing impurities of TiC and Ti5Si3 was fabricated by hot pressing elemental powders of Ti, Si, and C. X-ray diffractometry, scanning electron microscopy, and transmission electron microscopy were used to determine the crystalline phases and observe the microstructure of sintered c…
The dielectric constant of an incipient ferroelectric EuTiO 3 exhibits a sharp decrease at about 5.5K, at which the antiferromagnetic ordering of the Eu spins simultaneously appears. This fact indicates the existence of a coupling between the magnetism and dielectric properties of EuTiO 3 . We propose a possible coupl…