Materials Literature
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Abstract The anisotropic emission of the K‐X‐radiation of boron and nitrogen in hexagonal boron nitride BN permits the determination of the π‐ and s̀‐subbands of the two X‐ray spectra. Together with the X‐ray photoelectron spectrum a consistent picture of the valence band of BN is obtained. Position and width of the s…
The attachment of small glass spheres (<50 µm diameter) to the air–water interface is studied by micro-photography on a pendant drop in the presence of a cationic surfactant. The angle of wetting on the attached particles can be estimated from the photographs. Increasing the surfactant concentration increases this ang…
The pretransitional behaviour of a homologous series of mesomorphic compounds, the alkyl cyanobiphenyls (CNρρC n H 2n + 1) for n = 5–12, has been studied as a function of temperature by light scattering in the isotropic phase. The higher homologues, n = 8–12, exhibit a smectic A phase that becomes increasingly importa…
ОБЪЕМНЫЕ ВЗАИМОДЕЙСТВИЯ В СТАТИСТИЧЕСКОЙ ФИЗИКЕ ПОЛИМЕРНОЙ МАКРОМОЛЕКУЛЫИ, М, Дифгииц, А
A strong blue fluorescence has been observed following orange-yellow laser excitation in the 1D2 multiplet of Pr3+ : LaF3. This blue fluorescence has different time evolution depending on the excitation wavelength within the absorption line. Time resolved excitation techniques have been used to study this time evoluti…
Adiabatic elastic moduli for a NaCl single-crystal under high pressures up to 80kbar at room temperature were determined through ultrasonic sound velocity measurements in a cubic anvil-type high pressure apparatus with a solid pressure transmitter. Ultrasonic measurements far both the longitudinal and transverse waves…
Naturally occurring segment-long-spacing crystallites of procollagen collagen have been found in the culture medium of fibroblasts from chick embryo tendon, human skin, and dermatosparaxic calf skin; in whole-mount preparations of cultured human skin fibroblasts; in homogenates of lathyritic chick embryo tendon, carti…
The reentrant, nematic to smectic A phase transition is shown to follow from the Landau theory if one assumes the existence of an optimum density for smectic ordering. The shape of the coexistence line in the P-T plane is fit exactly by this theory. The effects of concentration on reentrant behaviour are also explaine…
In the course of investigations of organic metals we have investigated the cation-radical series TMTTF2-X′ with X′ = BF4, ClO4, PF6, SCN and Br. On this isomorphous series a large range of physical properties have been studied: electrical conductivity, magnetic susceptibility, EPR, optical reflectivity and specific he…
Abstract Adsorption of fibrinogen and albumin from solutions of the proteins singly and in mixtures was studied. A variety of surfaces with varying degrees of hydrophilicity and thrombogenicity was investigated. Adsorption behavior shows a strong dependence on surface properties. All surfaces show a preference for fib…
The photoluminescent and reflectance spectra of MgO smoke have been compared with the spectra of MgO ex-hydroxide and ex-carbonate. Parallel studies by electron microscopy have shown that a strong correlation exists between the optical spectra and the different morphology of the particles obtained by the different rou…
The inducible, mannitol-specific Enzyme II of the phosphoenolpyruvate:sugar phosphotransferase system has been purified approximately 230-fold from Escherichia coli membranes. The enzyme, initially solubilized with deoxycholate, was first subjected to hydrophobic chromatography on hexyl agarose and then purified by se…
Thermal expansion of γ-Mg2SiO4 was measured with X-ray powder diffraction method up to 750°C at atmospheric pressure. The data are analyzed in terms of Gruneisen's theory of thermal expansion and Gruneisen's parameter is obtained to be 1.27. Volume thermal expansion coefficient is 19 at 20°C and 27 at 500°C in unit of…
Nous avons mesuré les variations d'atténuation et de vitesse ultrasonores dans un gel acrylique. En comparant ces résultats avec ceux obtenus dans le solvant pur (H2O), nous avons pu en déduire la constante élastique propre du gel et le coefficient de friction entre le réseau et le solvant. Une étude en fonction de la…
A number of continuous random lattices can be classified as specific one-to-one mappings of ordered lattices of spaces of constant curvature onto the usual 3-dimensional euclidean space. These mappings put emphasis on two types of lattice defects : surface defects for spaces of constant positive curvature (i.e. spheri…
Atmospheric conditions, whether at room temperature or in high temperature ovens, do not consist of pure environments. Resorcinol-formaldehyde-latex (RFL) dipped nylon and polyester tire cords lose adhesion to rubber stocks upon exposure to environmental pollutants. Adhesion degradation is most severe upon exposure to…
The damage to three-dimensional orthogonal carbon-carbon composites created by particle impacts ranging from 1800 to 6000 ms-1 has been characterized for three weave constructions at both ambient and temperatures up to 3600¼C. The subsurface damage modes in the vicinity of the impact crater are described for the range…
The ultrasonic wave reflection method has been used to determine the elastic constants of various steels at the temperature range from room temperature to -196°C. Liquid nitrogen was used as a cooling agent. The data of the temperature dependence of elastic moduli for commercial alloys and steels were given in tables…
The fracture strength of two kinds of UO2 specimens possessing pores of different maximum sizes (60 and 140 μm) was measured in the range of room temperature − 1,300°C by means of diametral compression testing. The fracture strength thus obtained proved to be smaller than any of the values reported by previous authors…
It was found that sodium tetraphenylboron, NaB(C6H5)4, can be used as a reagent for determination of K in acid sodium acetate extracts of soils. After extraction and filtration, sodium hydroxide and formaldehyde are added prior to the reagent to avoid interference of ammonium. At low concentrations of K in the extract…