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。
Presently two well established cooling techniques prevail in crystallography: cold nitrogen-gas-stream cooling, which allows a minimum temperature close to the boiling point of nitrogen, 77 K, and closed-cycle helium refrigeration, which can reach temperatures even below 10 K. Some advantages and disadvantages of the…
A link between metal vacancy sites and magnetic ordering in the ion exchange intercalates of MnPS 3 has been established. High‐temperature X‐ray pattersn show that the formation of a metal vacancy superstructure and the transition to the magnetically ordered state are intimately linked, providing strong evidence that…
The [5, 10, 15,20-tetrakis((pentaammineruthenio(II))-4-pyridylporphinato ]cobalt(II) complex that catalyzes the fourelectron reduction of O_2 at graphite electrode surfaces on which it has been assembled has now been prepared in homogeneous solution. The preparative procedure for the catalyst is described, and the kin…
Surface‐oxidized phases on α‐silicon nitride, β‐silicon nitride, and silicon oxynitride powders were investigated by X‐ray photoelectron spectroscopy (XPS) and X‐ray Auger electron spectroscopy (XAES). The spectra of Si2 p XPS and Si( KLL ) XAES were measured precisely and were deconvoluted into some separate peaks, w…
The fabrication and crystallization of stoichiometric and near‐stoichiometric celsian, BaAl 2 Si 2 O 8 (BAS), glass made via melt and sol‐gel routes is reviewed. After considering celsian polymorphism and methods of stabilizing monoclinic celsian, some new experimental results are presented which show that melt glass…
An aqueous silver sol mean particle size 6 nm is mixed with KI and NaSH solution, and the changes in optical absorption and light scattering are recorded. When iodide adsorbs on the silver particles, the 225 nm band of I disappears concurrently with the decreasing of the silver plasmon absorption band. In the same tim…
Abstract Several important polymerizations [e.g., poly(methyl methacrylate) (PMMA), polystyrene] exhibit gel and glass effects during polymerization. These are associated with the decrease of the diffusivities of the macroradicals and monomer molecules with increasing viscosities of the reaction mass. A new model has…
The time correlation functions (CF's) of diagonal and off-diagonal components of the stress tensor of water have been calculated at 245 and 298 K in a molecular dynamics (MD) study on 343 molecules in the microcanonical ensemble. We present results obtained at wave number k=0 and at a few finite values of k, in the at…
We obtain the optical response of a multilayered system in which the interfaces have a common periodicity but arbitrary shape by extending a published method previously restricted to interfaces with identical profiles [ J. Opt. Soc. Am.72, 839 ( 1982)]. Numerical comparisons with other modeling results for grating sys…
Oxygen in oxide form is a common contaminant of BaFBr and BaFCl crystals. Upon x-irradiation of oxide-containing crystals of both materials, ${\mathrm{O}}_{\mathrm{F}}^{\mathrm{\ensuremath{-}}}$ centers are formed, as has been shown previously by electron paramagnetic resonance (EPR) methods. It is shown here by EPR t…
Results are reported of the Surface Tension Driven Convection Experiment (STDCE) aboard the USML-1 Spacelab, which was launched on June 25, 1992. In the experiment, 10 cSt silicone oil was placed in an open 10-cm-dia circular container, which was 5 cm deep. The fluid was heated either by a cylinderical heater (1.11 cm…
A PbTiO3 thin film prepared on silicon substrate by sol-gel technique has been studied by micro-Raman spectroscopy and x-ray diffraction (XRD). The spectra, in comparison to the single crystal work, show high background in the low frequency region and Raman lines are broader, thus revealing the polycrystalline nature…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAdsorption of Rhodamine 6G on saponite. A comparative study with other Rhodamine 6G-Smectite aqueous suspensionsF. Lopez Arbeloa, M. J. Tapia Estevez, T. Lopez Arbeloa, and I. Lopez ArbeloaCite this: Langmuir 1995, 11, 8, 3211–3217Publication Date (Print):August 1, 1995Publi…
We have performed extensive simulations of liquid carbon at various densities, using a highly transferable tight-binding model of carbon. In contrast to some recent theoretical suggestions, we show that the low-density liquid is primarily twofold bonded. Such a bonding arrangement leads to a low conductivity, compared…
High-resolution, magic-angle-spinning (MAS), 29Si NMR spectra have been obtained for a sodium silicate glass and liquid (60 mol% Si02) to temperatures over 600 °C. Crystallization was monitored in situ, and motional averaging of the peaks for distinct silicate anionic species (Q2 and Q3 species) in the liquid was obse…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAromatic Cyclolinear Phosphazene Polyimides Based on a Novel Bis-Spiro-Substituted Cyclotriphosphazene DiamineDevendra Kumar and Alka D. GuptaCite this: Macromolecules 1995, 28, 18, 6323–6329Publication Date (Print):August 1, 1995Publication History Published online1 May 200…
Electron-irradiated specimens of linear polyethylenes, aged at ambient conditions for periods between 79 and 112 months, were examined by electron spin resonance spectroscopy (ESR). Free radicals were found in all irradiated specimens, spin concentrations ranging from 0.5 × 1016 spins/g to 3.5 × 1016 spins/g and being…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTContribution of the Crazing Process to the Toughness of Rubber-Modified PolystyreneArminda M. L. Magalhaes and Rein J. M. BorggreveCite this: Macromolecules 1995, 28, 17, 5841–5851Publication Date (Print):August 1, 1995Publication History Published online1 May 2002Published…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Novel Dimanganese(III) Complex with a Single Hydroxo Bridge. Syntheses, Structures, and Magnetic Susceptibilities of (.mu.-Hydroxo)bis((octaethylporphinato)manganese(III)) Perchlorate and a Monomeric Precursor, Aquo(octaethylporphinato)manganese(III) PerchlorateBeisong Che…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTComparison of Chemically and Electrochemically Prepared Polyaniline Films. 2. Optical PropertiesDouglas Chinn, Joel DuBow, Jing Li, Jiri Janata, and Mira JosowiczCite this: Chem. Mater. 1995, 7, 8, 1510–1518Publication Date (Print):August 1, 1995Publication History Published…