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。
Anomalously large current plateaus observed in the cyclic voltammograms of some conducting polymers such as polypyrrole have been recently interpreted as the charging of a large capacitance taking place in the polymer in the oxidized state. The nature and the origin of such capacitance is actually discussed either in…
A fracture mechanics model is developed for nontransforming ceramics that show an increasing toughness with crack extension ( R ‐curve, or T ‐curve, behavior). The model derives from the observations in Part I, treating the increased crack resistance as the cumulative effect of grain bridging restraints operating behi…
Direct microscopic evidence is presented in support of an explanation of R ‐curve behavior in monophase ceramics by grain‐localized bridging across the newly formed crack interface. In situ observations are made of crack growth in tapered cantilever beam and indented flexure specimens of a coarsegrained alumina. The f…
In capacitors with metallized organic dielectrics electrical breakdown may be of great importance for reliability. In the case of pinholes in the dielectric, the thin electrodes in the surroundings are vaporized within a few μs and therefore the pinholes are insulated. This process is closely associated with gas react…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of five-coordinate high-spin iron(II) porphyrin complexes with unusually large quadrupole splittings. Models for the P460 center of hydroxylamine oxidoreductase from NitrosomonasH. Nasri, J. Fischer, R. Weiss, E. Bill, and A. TrautweinCite this…
Abstract Thermogalvanic cells containing a redox couple of [Fe(CN)6]4−⁄3− or Fe2+⁄3+ as an electroactive species were built for thermoelectric conversion from low-grade heat with a temperature less than 100 °C. The distance between high- and low-temperature electrodes was set to 1 mm in order to produce a high power d…
The mechanism of load transfer along unreinforced concrete interfaces by means of friction has been experimentally investigated for several surface roughnesses. The results of the parametric studies investigating the frictional behavior of interfaces under both monotonic and fully reversed large displacements are pres…
A one-dimensional transient thermal model has been developed to predict the thermal response of a decomposing, expanding polymer composite exposed to high temperatures. Both the decomposition and thermochemical expansion, as well as the storage of decom position gases in the solid material were considered in the formu…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSensitization of titanium dioxide in the visible light region using zinc porphyrinsK. Kalyanasundaram, N. Vlachopoulos, V. Krishnan, A. Monnier, and M. GraetzelCite this: J. Phys. Chem. 1987, 91, 9, 2342–2347Publication Date (Print):April 1, 1987Publication History Published…
Abstract Experiments were performed to validate the model for the nucleation of microcellular foams in amorphous thermoplastic polymers. The polystyrene‐zinc stearate system was chosen as the model system. Other additives such as stearic acid and carbon black were also investigated. Molecular weight and orientation ef…
Experimental data on phase relations in the CaCO3-MgCO3-FeCO3 ternary by Goldsmith et al. (1962) are inconsistent with those of Rosenberg (1967). These inconsistencies cannot be reconciled by the pressure or temperature differences between the two sets of experiments. Available reversed experiments on the binary syste…
Abstract Microcellular polymer foams exhibit greatly improved mechanical properties as compared to standard foams due to the formers' small bubble size. Microcellular foams have bubbles with diameters on the order of 10 microns, volume reductions of 30 to 40 percent, and six or seven times the impact strength of solid…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrochemical polymerization of amino-, pyrrole-, and hydroxy-substituted tetraphenylporphyrinsA. Bettelheim, B. A. White, S. A. Raybuck, and Royce W. MurrayCite this: Inorg. Chem. 1987, 26, 7, 1009–1017Publication Date (Print):April 1, 1987Publication History Published on…
A novel technique is presented for determining the coefficient of shear-induced particle self-diffusion in concentrated suspensions of solid spheres, which relies on the fact that this coefficient can be computed from the measured variations in the time taken by a single marked particle in the suspension to complete s…
Connections between the static density-functional theory of the glass transition and the dynamic mode-coupling theory of the glass transition are discussed. In three dimensions, some approximate equivalences are established. These equivalences are made more precise by examining high-dimensionality liquids and glasses.…
On passe en revue des travaux recents sur la preparation de ceramiques dielectriques pour condensateurs. On analyse la stabilite de la structure perovskites et les conditions de formation des phases pyrochlore
Abstract Microcellular foam is a polymeric foam with bubble sizes of 10 microns or less that is produced by saturating a polymer with gas and then utilizing the thermodynamic instabilities that result when the polymer is heated and the pressure is reduced to nucleate the cells. A model for the nucleation of microcellu…
A computer program has been written for the purpose of standardizing crystal structure data according to rules formulated by Parthé & Gelato [Acta Cryst. (1984). A40, 169–183]. From input consisting of space-group symbol, unit-cell parameters and positional coordinates of the atoms, a reordered and renumbered list of…
The application of the Rietveld refinement technique to synchrotron X-ray data collected from a capillary sample of Al2O3 in Debye–Scherrer geometry is described. The data were obtained at the Cornell High Energy Synchrotron Source (CHESS) with an Si(111) double-crystal monochromator and a Ge(111) crystal analyzer. Fi…
A room-temperature nematic liquid crystal cell is prepared in the homeotropic geometry using dielectrically positive pentyl cyanobiphenyl. The indium tin oxide electrodes are treated to increase locally their surface resistance. At high frequencies (ω>ωc) the border of these regions behaves as capacitance edge,…