Materials Literature
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A method is presented allowing the determination of the three principal values (${\mathrm{\ensuremath{\varepsilon}}}_{1}$,${\mathrm{\ensuremath{\varepsilon}}}_{2}$,${\mathrm{\ensuremath{\varepsilon}}}_{3}$) of the dielectric tensor for a chiral smectic-C liquid crystal in the case that the material has an uncompensate…
The corrosion resistance of three types of iron phosphate coatings on cold-rolled steel was examined. The alkali metal phosphating baths studied were three of the types most commonly encountered in industrial finishing operations. Coating composition was varied by using different accelerators in the phosphating bath.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReversible uptake of hydrogen and nitrogen at cobalt in the solid state. Influence of the counter anion on the formation of classical dihydride vs. nonclassical .eta.2-dihydrogen forms of [(PP3)CoH2]+Claudio Bianchini, Carlo Mealli, Maurizio Peruzzini, and Fabrizio ZanobiniC…
Plasma membranes of the thermoacidophilic archaebacterium Sulfolobus acidocaldarius (DSM 639) display a pyrophosphate-hydrolyzing activity [M. Lübben & G. Schäfer (1987) Eur. J. Biochem. 164, 533-540]. In our present work, we solubilized and purified this pyrophosphatase to homogeneity. It consists of a single subunit…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheoretical investigation of the geometric structures and the second-order nonlinear optical properties of 8-hydroxyquinoline derivativesMamoun M. Bader, Tomoyuki Hamada, and Atsushi KakutaCite this: J. Am. Chem. Soc. 1992, 114, 16, 6475–6479Publication Date (Print):July 1,…
A theory of the banded domain a-structures in tetragonal ferroelectric ceramics is presented. The mechanical sources of internal stresses appearing on the grain and band boundaries at a phase transition are modelled by arrays of wedge disclinations and continuously distributed fictitious dislocations. With the aid of…
Tilt domains are dynamical defects of cellular growth fronts consisting of a group of asymmetric cells traveling laterally along the front. We study the dynamics of these defects in thin-film directional solidification of the ${\mathrm{CBr}}_{4}$-${\mathrm{C}}_{2}$${\mathrm{Cl}}_{6}$ eutectic alloy. We show that the s…
Abstract Shooting experiments over short distances (30 to 50 cm) deposited apparently non-burnt and partially burned flakes of smokeless powder propellants on clothing around the bullet holes. An approach was made to compare the propellant particles recovered from the clothing with those from a particular cartridge. E…
Abstract The syntheses of three methacrylate monomers with cinnamate ester side‐chains and of a further monomer with a corresponding cinnamide side‐chain are described. Two of the monomers, with isomeric structures, were thermotropic liquid crystals. Although the clearing points were very similar the crystal melting p…
Two orthorhombic Al–Mn–Cu phases, π-Al20Mn3Cu2 and Y-AlMnCu, with large lattice parameters were found to coexist with the decagonal quasicrystal in Al10Mn3Cu0.1-0.2 alloys and they were shown to be crystalline approximants of the latter. These two phases have similar structural subunits and a close orientation relatio…
Constant compressive stress creep experiments in the temperature and stress ranges of 1770 to 2020 K and 35 to 373 MPa have been performed on polycrystalline alpha SiC. Specimens having average grain sizes of 3.5, 4.9, and 7.5 μm have been studied in order to determine the grain size dependence of steady‐state creep i…
Very high oxygen coverages−up to θO ≊ 40 (forty)−were obtained by dissociative adsorption of NO2 on Ru(001) at elevated temperatures. O2 desorption data show three desorption peaks at ≊1100, ≊1000, and ≊900 K, and suggest strong oxygen–oxygen repulsions in the overlayer. An Arrhenius plot of the leading edge desorptio…
The tests carried out in Brazil indicate that a composite material including vegetable fibres of the coir type are suitable for outdoor use in environments similar to that found in São Paulo.
A mean field theory of dipole-dipole correlation in nematic liquid crystals is developed by modelling the anisotropic radial distribution function for two hard ellipsoids. This, combined with a dipole-dipole interaction energy, allows the calculation of Kirkwood dipole correlation factors for uniaxial and biaxial part…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation and structure of ruthenium tetrafluoride and a structural comparison with ruthenium trifluoride and ruthenium pentafluorideWilliam J. Casteel Jr., Angus P. Wilkinson, Horst Borrmann, Robert E. Serfass, and Neil BartlettCite this: Inorg. Chem. 1992, 31, 14, 3124–3…
The equations properly describing the diffusion–controlled reaction of a spherical particle to form a concentric spherical shell of product are set up then solved numerically and their predictions compared with those of the commonly used approximate models due to jander, Ginstling and Brounshtein, and Valensi or Carte…
Barium titanate (BaTiO 3 ) thin films have been deposited on single‐crystal magnesia (MgO) substrates by pulsed‐laser ablation. Temperature dependence of capacitance measurements show a peak of 110°C, indicative that a ferroelectric phase transition has occurred at this temperature. This value is lower than that deter…
The thermal diffusivity and thermal conductivity of single crystal (100) lanthanum aluminate (LaAlO3) have been determined in the temperature range 77–353 K. The thermal diffusivity was measured using a transient heat-pulse technique and the thermal conductivity by a steady state dc technique. The specific heat capaci…
1. The protein components of the domestic fowl's eggshell are believed to influence appreciably the mechanical properties of the shell and/or its biomineralisation. The purpose of this study was to compare the protein species composing the eggshell matrix in different parts of the shell structure, by SDS-PAGE and chro…
Discotic charge transfer twins, a novel class of discotic liquid-crystalline compounds were studied. These compounds consist of triphenylene units (as donors) which are chemically linked via flexible spacers of various lengths to trinitrofluorenone units (acting as acceptor). They display a liquid-crystalline phase ov…