Materials Literature
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The elastic Gibbs function for BaTiO3 introduced by Buessem, Goswami and Cross1 has been modified by including the last symmetry permitted sixth order term HP12P22P32 with a coefficient H = 4.91 × 109 Vm9 C-5. The function predicts the correct high electric field behavior of the low temperature ferroelectric: ferroele…
We have combined the Maier Saupe theory [1] of the nematic-isotropic transition and the Flory Huggins theory of mixtures to describe the phase diagrams of two nematogens A + B. The two components can have different order parameters SA, SB in the mixture. We can then predict the morphology of the phase diagrams in term…
The precipitation of calcium carbonate from aqueous solutions has been studied at supersaturations sufficient for spontaneous precipitation but low enough to enable highly reproducible experiments to be carried out with respect to induction periods and rates of precipitation. The threshold for the onset of calcium car…
Photoexcitation of the oxygen-to-metal charge-transfer band (323 nm, ε= 1.35 × 104 dm3 mol–1 cm–1) of [NBu4]4[W10O32] in acetonitrile results in the reduction of WVI to WV[quantum yield, φ=(1–2)× 10–2] with accompanying formation of 1-butene in less than stoicheiometric yield (70%). Prolonged irradiation leads to the…
Temperature dependence of neutron diffraction intensities of PbZrO 3 was measured in the room-temperature antiferroelectric phase. Intensities of strong superlattice reflections with wave vectors q Σ ≡(1/4 1/4 0) and q R ≡(1/2 1/2 1/2) show different temperature dependence each other. Intensities of weak superlattice…
A method of mathematically analyzing interdendritic microsegregation was established using finite difference method and taking into consideration the diffusion of the solute in the solid and liquid phases. The cross-sectional shape of dendrites and the fact that the enrichment of the solute in the liquid phase at the…
Sintered pellets of CeO2 and UO2, as well as PuO2 powder, have been irradiated with alpha particles emitted from an effectively semi-infinite 238PuO2 source. The lattice parameters of all three materials increased with dose, Dα, according to the expression δa/a0 = A[1—exp(—BDα)], in agreement with a previously develop…
Samples of anatomically and functionally distinct regions of the skin of a variety of altricial and precocial animals were taken at various stages of development from birth to beyond maturity. The glycosaminoglycan (GAG) content and composition of the tissues were determined by chemical analysis and the collagen fibri…
Anodic dissolution of aluminum in hot chloride solutions produces a high density of fine etch tunnels that extend along [100] directions. Tunnels evolve from cubic etch pits when all but one of the pit wall surfaces become passivated; dissolution then occurs at the one active face at a rate that may initially be as hi…
Chalcogenide glass fibers for mid-infrared transmission have been fabricated in As-S, As-Ge-Se, and Ge-S glass systems using high purity materials. The preparation of unclad, Teflon FEP clad, and chalcogenide glass clad fibers and their transmission loss characteristics are reported. It is found that appropriate glass…
In order to assess the high temperature vaporization behavior and equilibrium gas phase compositions of binary alkali metal oxides, the relevant thermodynamic and molecular constant data have been compiled and critically evaluated. Selected values of the Gibbs energy and enthalpy functions of condensed and vapor phase…
The smectic state has been known for over a century but is currently being very actively investigated. We review the polymorphism associated with one-dimensional ordering, critical phenomena characteristic of the several phase transitions encountered in these systems, together with their very special dynamical propert…
Stable aqueous colloidal platinum sols have been prepared by the citrate reduction of chloroplatinic acid. Particle size at the completion of the reaction was found to increase with increased heat input during reduction. The u.v.–visible spectrum of the platinum sols depends upon particle size up to 4 nm. A stirring–c…
The mechanical properties of chemically vapor‐deposited boron carbides (B 4 C) with varied B/C ratios were investigated as a function of composition. The maximum hardness, H, and fracture toughness, K 1c , were observed at an almost stoichiometric composition. For nonstoichiometric B 4 C (B/C>4), H and K 1c decreas…
Abstract The kinetics of K exchange were investigated in Ca‐saturated samples from the Ap horizon of an Evesboro soil from Delaware. Biphasic kinetics characterized the first‐order plots for K adsorption and desorption at 283 and 298K with the two simultaneous reactions being attributed to exchange sites with varying…
The effects of applied pressure on graphite and its intercalation compounds are reviewed emphasizing the relationship between structure and transport properties. It has long been recognized that high pressure plays a crucial role in the polymorphic phase transitions of graphite, notably in the graphite-diamond transfo…
(1984). Surface-stabilized ferroelectric liquid crystal electro-optics: New multistate structures and devices. Ferroelectrics: Vol. 59, No. 1, pp. 25-67.
The most recently developed diagnostic technique in metal-electrolyte and metal-gas interfaces adapts spontaneous Raman scattering and nonlinear optical generation, techniques normally applied to bulk media, to surface science investigation. For certain metallic surfaces, an enormous increase exists in the Raman (as m…
Meso-tetra(2,6-dichlorophenyl)porphinatoiron(III)chloride and meso-tetra(pentachlorophenyl)porphinatioiron(III)chloride, which resist µ-oxo dimmer formation and oxidative destruction, are found to be unusually efficient catalysts for high-turnover, high-yield alkene epoxidation and alkane hydroxylation.
Colloidal particles of CdS are produced by adding H2S to aqueous solutions of Cd(NO3)2(method 1) or rapid mixing of Na2S and Cd(NO3)2 solutions (method 2). Single crystals with cubic structure are obtained, their size being 50 and 20 Å, respectively. Type 1 particles are associated as dimers or trimers while type 2 pa…