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。
Fracture characteristics and mechanical properties of advanced structural ceramics produced by advanced technology and developed for high temperature applications are reviewed from the viewpoint of fractography. The main processing routes for preparation of in situ reinforced ceramic matrix composites, nanocomposites,…
Eleven new polyoxoanion-supported transition metal acetonitrile compositions have been synthesized in 1:1, 1:2, and even a few 1:3 M n + to polyoxoanion ratios; these new precatalysts were then tested for their catalytic efficacy for norbornene and cyclohexene oxygenation using [PhIO] n as the oxidant. The catalytic r…
Piezoelectric ceramics are widely used in industry in such devices as transducers and actuators. While bulk ceramics perform well in most applications, they are limited in use as actuators where large strains are needed. This research examines bulk piezoelectric ceramics with functional gradients of composition in ord…
Results of Wannier orbital-based Hartree–Fock and various correlated ab initio calculations using 6–31G** basis sets are reported for the two boron–nitrogen polymer systems polyaminoborane [BNH4]∞ and polyiminoborane [BNH2]∞. At the Hartree–Fock level the calculated equilibrium geometries, cohesive energies, polymeriz…
Char forming polymers, particularly cellulosics, can best be flame retarded by chem icals that function in the condensed phase. Under heat or fire conditions, these flame retardants enhance crosslinking and aromatization reactions of the polymer at the ex pense of volatilization, leading to increased char formation. I…
29 Si MAS‐NMR, and Ca‐EXAFS experiments have been conducted on calcium silicate hydrates (C‐S‐Hs) with structure derived from wollastonite. Crystalline compounds (wollastonite, xonotlite, hillebrandite, foshagite, 1.1 nm and 1.4 nm tobermorites, and jennite) and C‐S‐H were synthesized and characterized. 29 Si NMR prov…
The path-integral effective-potential (EP) method was applied to the calculations of EXAFS cumulants. The EXAFS cumulants up to the fourth order for diatomic Br2 were evaluated and compared to the results by the first-and second-order perturbation theory and also the experiments. The second-order perturbation formulas…
Microwave dielectric studies on the dynamics of water in poly(vinylpyrrolidone) (PVP)−water mixtures and 1-vinyl-2-pyrrolidinone (VP)−water mixtures were performed to compare the relaxation processes of water in polymer−water and monomeric compound−water mixtures. For the PVP−water mixtures, a relaxation peak for wate…
Changes in the chemistry of the acidic Chilean Andisols in response to various ameliorant treatments (gypsum, dolomitic, and calcitic limestone) and their effects on ryegrass (Lolium perenne) production were studied in laboratory incubation and greenhouse experiments. Dolomitic and calcitic limestone alone and in comb…
The longitudinal and transverse ultrasonic velocities and attenuations of single-phase polycrystalline colossal magnetoresistance compound ${\mathrm{La}}_{0.60}{\mathrm{Y}}_{0.07}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}$ have been measured at a frequency of 10 MHz, between 50 and 300 K. At the ferromagnetic and insulato…
Molecular dynamics simulations were performed on the relaxation of fully extended polyethylene chains, varying in length from 600 to 4000 CH2 units. When a chain has more than 1200 CH2 units, the relaxation proceeds in three stages, subglobule formation, subglobule growth, and subglobule coalescence into one globule.…
The complexes [Yb(bind)2(DME)2], [Yb(MePhpz)2(DME)2], [Yb(azin)2(DME)2], and [Eu(Ph2pz)2(DME)2] (bindH = 4,5-dihydro-2H-benz[g]indazole; MePhpzH = 3-methyl-5-phenylpyrazole; azinH = 7-azaindole; Ph2pzH = 3,5-diphenylpyrazole; DME = 1,2-dimethoxyethane) have been prepared by redox transmetallation between ytterbium or…
Manganese zinc (MnZn) ferrite powders were prepared via the hydrothermal treatment of a homogeneous mixture of the raw oxides (i.e., Fe 2 O 3 , ZnO, and Mn 3 O 4 or MnO) at temperatures of 220°‐320°C in air or an inert atmosphere. The final results of the hydrothermal reactions between the raw oxides were fine powders…
We investigate theoretically a novel experimental polymer route to C 3 N 4 materials. Starting with simple molecules, we follow the initial steps of oligomerization of several carbodiimide based C 3 N 4 precursors. A sequence of hypothetical models with a chemically resonable structure for the resulting low-density C…
Thermal degradation of bisphenol A polycarbonate (PC) has been studied in nitrogen and air from room temperature to 900 °C by high-resolution thermogravimetry (TG) with a variable heating rate in response to changes in the sample's degradation rate. A three-step (in nitrogen) or four-step (in air) degradation process…
The relative ease with which alumina–SiC nanocomposites polish, compared with monolithic alumina, has been noted in the literature and taken to be an example of the beneficial ‘nanocomposite effect’ stemming from an apparent strengthening of the grain boundaries. The percentage of ‘polished’surface, as opposed to area…
This study investigates the characteristics of permanent magnet assisted synchronous reluctance motor (PMASynRM) using coupled FEM and Preisach modelling. The focus of this paper is the characteristics analysis of d, q axis inductance according to magnetizing direction and quantity of interior permanent magnet for PMA…
The formation of scale on heat transfer surfaces during pool boiling is a frequent engineering problem where aqueous solutions are involved. In this investigation the effect of modified surfaces on deposition of calcium sulfate on heat transfer surfaces was studied. The surfaces were either implanted with ions such as…
This paper presents a system for assessing yarn structure. Image analysis techniques and mathematical methods are used to develop the method of estimating basic structural parameters of yarn thickness, hairiness, and twist. The method provides numerical characteristics of the structure at each point of the yam length.…
Single bubble sonoluminescence in an air-water system has been shown to occur along a unique surface in the acoustic pressure-ambient radius-gas concentration parameter space where the bubble is stable both in shape and in (average) size. In this paper, we show how the bubble deviates from the expected path (traced by…