Materials Literature
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Abstract Laser-photolysis studies have been carried out on a solution of 9-diazo-10,10-dimethyl-10-sila-9(10H)-anthracene in cyclohexane. In aerated solutions, the triplet 10,10-dimethyl-10-silaanthracen-9(10H)-ylidene was quenched with oxygen (kq=2×109 M−1s−1) to give a characteristic absorption (λmax at 425 nm) due…
It is shown that, for transition-metal trichalcogenides Nb${\mathrm{Se}}_{3}$, for Ta${\mathrm{S}}_{3}$ both with a monoclinic and an orthorhombic unit cell, and for transition-metal tetrachalcogenide ${(\mathrm{T}\mathrm{a}{\mathrm{Se}}_{4})}_{2}$I, compounds which exhibit transport properties associated with charge-…
Abstract 57 Fe Mössbauer spectra of a cleaned Weipa, Australia, kaolin showed that a considerable fraction of the structural iron exhibits paramagnetic relaxation between 4°K and 300°K, the first time that this has been observed for ferric ions in a mineral. The sample also contained a very fine particle ferric oxide/…
The crystal structure of the title compound, [CO(C15H11N3)2] 12.2H2O, has been determined by single crystal X-ray diffraction methods at 295 K and at 120 K, being refined by least squares to residuals of 0.051 and 0.035 respectively for 982 and 1024 'observed' reflections at these temperatures. Both structures are bas…
Fused mullite, pure and with 10 to 25 vol% ZrO 2 added, was milled in an attritor and sintered in air at temperatures near 1600°C to a dense fine‐grained ceramic. The ZrO 2 promoted densification and retarded grain growth of the mullite phase. Transmission electron microscopy showed that compositions containing ZrO 2…
The energy-loss distribution for pions and protons, with momenta between 0.7 and 115 GeV/c, has been measured in an ion-implanted detector of 300 \ensuremath{\mu}m thickness. The data are well described by an empirical energy-loss distribution.
The interpretation of quantitative assays for leukocyte chemotactic migration is usually made in terms of measurements such as leading front distance, total migrating cells, and leukotactic index. These quantities allow comparison of cellular migration behavior under specified conditions. They are not useful; however,…
It has been demonstrated directly by use of x-ray diffraction that at temperatures below the triple point of bulk ethylene (103.8 K) adsorption of ethylene onto the basal planes of graphite only occurs up to a finite number of molecular layers. Further addition of molecules results in the formation of bulk crystallite…
The use of selected organosilicon compounds for the preparation of silicon based ceramic materials is discussed in terms of processing microstructure-property relationships. The mechanisms operative in the formation of gel derived silicate glasses and glass ceramics are reasonably well understood, but this is not true…
Mössbauer spectra of a polycrystalline form of oxidized chloro-5,10,15,20-tetra(mesityl)porphyrin- atoiron(III) [Fe(TMP)Cl], compound A, were recorded over a range of temperatures (4.2–195 K) and magnetic fields (0–6 T). These spectra of compound A exhibit magnetic features which are markedly different from those of t…
The first study of the atomic structure of Si chalcogenide glasses is reported. The Raman spectra are remarkably simple and can be understood in terms of the vibrations of a bitetrahedral ${\mathrm{Si}}_{2}{({X}_{\frac{1}{2}})}_{8}$ ($X=\mathrm{S},\mathrm{S}\mathrm{e}$) unit. The present results represent the most com…
The nucleotide sequence of a 1,163-base-pair fragment that encodes the entire thyA gene of Escherichia coli K-12 was determined. The strategy involved sequence determination of both DNA strands by using overlapping deletions that had been generated in vitro from the two ends of the fragment with BAL-31 nuclease. The a…
The thermodynamics of a system of identical electrically charged spheres in colloidal suspension in a polar fluid (typically, H2O), are calculated within a model of point particles interacting via a screened Coulomb (Yukawa) potential of suitably renormalized strength. The particles are taken to be sufficiently massiv…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMesophase formation and chain rigidity in cellulose and derivatives. 1. (Hydroxypropyl)cellulose in dimethylacetamideG. Conio, E. Bianchi, A. Ciferri, A. Tealdi, and M. A. AdenCite this: Macromolecules 1983, 16, 8, 1264–1270Publication Date (Print):August 1, 1983Publication…
Octalithium zirconate was prepared by heating a pelletized stoichiometric mixture of fused lithium oxide and zirconium dioxide under a dynamic vacuum to 863 K for 40 h. The melting point was determined to be 1568 ∼5 K. Chemical inertness and high lithium atom density, 5.93 ∼10 22 atoms /cm 3 , make octalithium zircona…
A detailed reproducible procedure has been developed for the replication of human skin for scanning electron-microscopic evaluation. Utilizing a test surface, a number of negative and positive materials were evaluated for consistence and clarity of replication. Optimal replication parameters were determined and the me…
Abstract The reinforcement mechanism of polyester tire cord was studied by Fourier‐transform infrared spectroscopy using various model compounds. Three model compounds representing the main chain of polyester and the terminal groups, namely carboxylic acid and hydroxyl groups, were used. Chemical reactions between the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTX-ray diffraction and thermal analysis of molybdenum(VI) oxide hemihydrate: monoclinic MoO3.1/2H2OR. L. Fellows, M. H. Lloyd, J. F. Knight, and H. L. YakelCite this: Inorg. Chem. 1983, 22, 17, 2468–2470Publication Date (Print):August 1, 1983Publication History Published onli…
The phonon spectral function for charge density wave (CDW) systems in the superconducting (SC) phase is calculated for finite wave vectors (q). An exact expression for the q dependent phonon self-energy is obtained. The analysis is carried out with a small q limit. The spectral function shows a two peak structure for…
Abstract The initiation and build‐up to detonation of Composition B covered by steel barrier plates and impacted by a shaped‐charge jet has been studied. Two different barrier thicknesses were used representing strong and weak shock initiating systems. The results showed that, in both cases, a shock (designated the pr…