Materials Literature
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Abstract In the Tertiary lacustrine sediments of the Jbel Rhassoul (Morocco), stevensite and sepiolite, confined to the dolomitic facies, are commonly mixed at lower parts of the so-called “Formation Intermédiaire”. Transmission electron microscopy (TEM) observations reveal a relation between these 2 magnesian clay mi…
Abstract The crystal structure of averievite, Cu 5 O 2 (VO 4 ) 2 ·n MX has been determined. Trigonal system, space group P 3, a = 6.375(1), c = 8.399(1) Å, V = 295.6(1) Å 3 , Z = 1, D x = 4.01(1) g/cm 3 . The atomic arrangement is characterized by infinite nets parallel to (001) composed of [OCu 4 ] 6+ tetrahedra link…
Abstract The thermal stability of poly( L ‐lactide) and L / D ‐lactide stereocopolymers polymerized in bulk with aluminium isopropoxide as initiator was investigated by thermogravimetric analysis, and time and temperature dependence of molecular weight and polydispersity. Compared to poly( L ‐lactide) prepared with st…
Current leads, which connect superconducting magnets at the liquid helium temperature and power supplies at the room temperature, are the major source of heat leaking into cryostats, and therefore largely determines the running cost of magnet systems. Heat leak can be reduced by using high-temperature superconductors…
The slowing down of energetic particles in solids has been studied for the special but important case that the energy loss process is independent of any other interaction characteristic. For a realistic variation of the scattering characteristics with energy this allows one to go over from the continuous energy variab…
Ferromagnetic resonance measurements were made as a function of the static external field angle for c-plane disks of single crystal flux grown manganese substituted barium M-type (Ba-M) and zinc Y-type (Zn-Y) hexagonal ferrites at 50 and 8.8 GHz, respectively. A shorted waveguide technique was used. Analysis of the FM…
Carbon diffuses into metal and recrystallizes as graphite, which is termed graphitization of carbon by metal. This study has revealed that the temperature at which this graphitization occurs depends on the initial state of the carbon. The lowest temperatures at which graphitization by Ni occurs for diamond, diamondlik…
Detailed voltammetric studies are reported of the reduction of alpha-[S(2)Mo(18)O(62)](4)(-) at glassy carbon and platinum macro- and microdisk electrodes (stationary and rotated) in acetonitrile and in 95/5 acetonitrile/water mixtures containing 0.02 M perchloric acid. Experiments at -30 degrees C and at short time s…
Wide-angle X-ray diffraction patterns of single spider-silk fibres of ≤ 5 μm diameter can be obtained at a third-generation synchrotron-radiation source in a few seconds per pattern. This is sufficient to observe the strongest equatorial and first layer line reflections. For higher-resolution structural work, data hav…
Abstract The crystal structures of IrAl 2.75 (“Ir 2 Al 5 ”) and RhAl 2.63 (“Rh 2 Al 5 ”) phases have been studied with single crystal methods: space group P 23, IrAl 2.75 , a = 7.674(1) Å, Z = 8, R F = 0.053 (457 hkl , 29 parameters) and RhAl 2.63 , a = 7.6692(1) Å, R F = 0.042 (684 hkl , 29 parameters). The unit cell…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTOn the Landau−Brazovskii Theory for Block Copolymer MeltsI. W. Hamley and V. E. PodneksView Author Information School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K. Cite this: Macromolecules 1997, 30, 12, 3701–3703Publicatio…
The effects of weather conditions such as temperature and pressure on contamination flashover voltage of insulators were investigated theoretically, combining reported empirical relations. The flashover voltage theoretically calculated by the authors were compared with experimental data obtained in various parts of th…
Author: Geiger, C. A. et al.; Genre: Journal Article; Finally published : 1997; Title: Molar volumes of mixing of almandine-pyrope and almandine-spessartine garnets and the crystal chemistry and thermodynamic mixing properties of aluminosilicate garnets
The pretilt angle (Θ p ) of nematic liquid crystals (LCs) could be controlled with alignment layer (AL) polyimides (PIs) and/or LCD processes in the case that a cell gap and a rubbing condition are fixed. Θ p was increased by introducing long, linear alkyl side chains and/or other nonpolar groups to the AL polyimide.…
We study the orientational states induced in nematic liquid crystals by microtextured substrates with a spatially mixed pattern of different aligning potentials on the mesoscopic scale, i.e., on the order of 0.5 \ensuremath{\mu}m or less. We show that within the Landau--de Gennes framework, the existence of a finite e…
The IR and Raman spectra of the monosubstituted hydrosilasesquioxanes RH 7 Si 8 O 12, R = Co(CO) 4, Ph, CH CHPh, and CH 2 CH 2 Ph, have been analyzed by spectral correlation and a normal coordinate analysis. They were treated as a superposition of the spectra of the siloxane cage and the substituent. The molecules PhH…
Molecular dynamics of cascades in pure iron and iron–copper alloys using embedded atom method type of interatomic potentials are presented. Reliable simulations of radiation damage at the atomic scale with high energy Primary Knocked Atoms (PKA) need systems with large numbers of particles and very long computational…
High quality semiconducting boron‐doped polycrystalline diamond thin films were prepared on Si substrates via microwave plasma chemical vapor deposition. The resistivities of the lightly doped films were on the order of 10 2 Ω cm. The photoelectrochemical behavior was studied with excimer lasers of several different w…
Abstract Oxidation of cellulose by chlorine, bromine, hydrogen peroxide and ozone and the functional groups formed are reviewed. The roles of the pH and of the nature of the oxidant in the formation of carboxy‐ and keto‐celluloses are discussed. The relationships between the functional groups, degradation and stabilit…
It is difficult to go through a whole day without coming in contact with something which does not contain a foamed plastic part somewhere within. The most common examples perhaps are the foamed polyurethane seat cushion of the sofa or chair or the car-seat that you sat on this morning, or the polystyrene foam cup in w…