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。
The hydrogen exchange reaction of surface OD groups on MgO with H2(—OD + H2→—OH + HD) has been investigated in order to understand the relationship between the activity and the local structure of the surface hydroxyl groups by means of i.r. spectroscopy. OD groups on the Mg atom are composed of three types exhibiting…
A new laboratory wear test for simulating cutting tool wear is proposed in which the contact conditions in machining are reproduced by letting a tool material pin slide continuously against a fresh countermaterial surface. Wear tests with high speed steel (HSS) pins in the uncoated and TiN coated conditions have been…
Symmetry determination of three-dimensional (usual) crystals, four-dimensional (one-dimensionally incommensurate) crystals and five- and six-dimensional crystals (quasicrystals) by convergent-beam electron diffraction is described and demonstrated using real materials. Crystal structure refinement based on the dynamic…
Austenitic stainless steels (alloys 304, 316, 310) have been immersed in acidified 15M LiCl solutions at 90°C and analysed by Auger electron spectroscopy. The tarnish films formed on the 304 and 316 steels contain some oxygen, but otherwise have compositiondepth profiles similar to those of dealloyed metallic layers.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSmall-angle light scattering from nematic liquid crystals: fluctuations of director field due to many-body interactions of disclinationsT. Hashimoto, A. Nakai, T. Shiwaku, H. Hasegawa, S. Rojstaczer, and R. S. SteinCite this: Macromolecules 1989, 22, 1, 422–429Publication Da…
Abstract The concepts of coherence and composition paths, originally developed for multicomponent chromatography, are used to establish a simple theory of transport in systems with precipitation and dissolution in the course of multicomponent, single‐phase flow in permeable media. Composition route construction in pha…
The glass-forming regions in the ternary systems LiX (X=F and Br)-Li2O-TeO2 were established in the present study. For X=Br the glass-forming region was found to be widened up to about 75mol% LiBr on the LiBr rich side compared to the system containing LiCl which was studied previously, while the region for X=F was re…
Veneer-faced low-density particleboards were made using four combinations of control and acetylatcd veneers and particles.These boards were tested for dimensional stability in both liquid water and water vapor, for decay resistance in standard soil-block tests with Tyrornyces palustris and Trametes versicolor, for str…
Mechanical behavior of Al2O3-based ceramics can be improved by dispersion of pure or partially stabilized ZrO2 particles. The effective toughening or strengthening effect, which is operating in these composite materials, is determined by microstructural characteristics (composition, processing conditions) and environm…
A pronounced synergetic effect has been found when LaMn1–xCuxO3(x= 0.3–0.5) was prepared by a freeze-drying method from metal acetates of each component; LaMn0.6Cu0.4O3 showed much higher catalytic activity for the reactions of CO–O2 and NO–CO in comparison with LaMnO3 and La2CuO4.
The electrochemical behaviour of polyaniline (PAn) in weak acid solutions such as pH 4 has been studied. It has been found that PAn gives a stable redox reaction involving electrolyte anions in a limited potential region, whereas it loses its electrochemical activity by being oxidized at more anodic potentials where d…
A bis(4-pyridyl)-porphyrin has been synthesised and shown to bind within the cavity of a host metalloporphyrin–pyromellitimide dimer; fluorescence quenching of the bound guest implies a photoinduced electron transfer to the pyromellitimide moieties of the host molecule.
X-ray diffraction patterns from layered structures yield detailed information on their structural parameters such as strain profile, chemical composition, layer thickness and interface quality. Any variation of the period, thickness of the individual layers, composition and homogeneity of the supelattics can be also d…
The barrier height for tautomerism of the inner protons of porphyrin is significantly influenced by specific reduction of the pyrrole rings. In the tetraphenyl derivatives of chlorin and bacteriochlorin an aromatic ring current was established 1 H NMR spectroscopically; in contrast, in the tetraphenyl derivative of is…
Intramolecular π–π interactions in two cofacial zinc porphyrin dimers have been probed as a model for porphyrin–porphyrin aggregation. Comparative studies of the binding of substituted pyridines using n.m.r., u.v./visible absorption and emission spectroscopy have allowed separation of the steric and electronic contrib…
It has long been a major preoccupation of materials users, whether implied or explicit, to tailor microstructures in order to adapt specific properties for a given application. In this context, the principal aim of the present review article is to consider the fundamental elements of polycrystal microstructures, i.e.…
Abstract Photoresponsive macromolecules are of interest both as novel organic materials for applications in photodevices and as models for photomodulated biological processes. The presence in polymer chains of photosensitive groups and of chiral groups capable of inducing optical activity into the polymer is very usef…
The time-resolved emission spectra of the tetranuclear clusters Cu4I4(py-X)4(X = H, 3-Cl, 4-Ph, 4-PhCH2, or 4-But) at 296 K in toluene each display separate, uncoupled emissions from two states, a short-lived (0.13–0.56 µs) metal-to-ligand charge transfer in the range 473–537 nm and a much more intense and longer live…
The microstructure evolution and grain growth during high-temperature heat treatment in ZrO2–4 and 8mol%Y2O3 alloys were examined. ZrO2–8mol%Y2O3 alloy was of single cubic phase (c-ZrO2), while ZrO2–4mol%Y2O3 alloy consisted of mixed grains of c-ZrO2 and tetragonal phase (t-ZrO2) with the equilibrium yttria contents a…
Thermal diffusivity and conductivity as well as specific heat of capsule-HIPped Si3N4 with Y2O3 and Al2O3 6mol% in total as additives were measured at different temperatures ranging from 100 to 1300K. The isobaric specific heat Cp agreed with the isochoric specific heat Cv calculated by the Debye's theory, assuming th…