Materials Literature
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Each of the formate, acetate, monochloroacetate, trichloroacetate, phenylacetate, and benzoate complexes iron (III), prepared and characterized for study is triangular trinuclear in structure and contains six bridging carboxylate ligands and a central bridging oxygen. Magnetic susceptibility measurements from room tem…
We present results of a self-consistent band calculation of the ground-state energy and charge orderings based on a tight-binding scheme in magnetite. The calculation is greatly simplified by making use of the large intra-atomic Coulomb interactions between electrons on the Fe ions, previous estimates of the crystal f…
The vibronic theory of ferroelectric phase transitions is reviewed and the essential contribution of electron-phonon interaction into the microscopic origin of the ferroelectricity is demonstrated. In the narrow-gap (semiconducting) systems the soft mode is caused by interband vibronic interaction and the temperature…
In order to characterize the ultrastructural alterations of cells, vasculature and fibrils that occur on the pressure side of the periodontal ligament when teeth are subjected to orthodontic forces of a magnitude generally used in clinical practice, eleven premolar teeth were moved buccally by means of a fixed applian…
A rate theory of the growth of irradiation-produced interstitial loops in uniaxially stressed materials which also contain voids, coherent and/or incoherent precipitates and network dislocations is derived and the resulting creep behaviour is determined. Allowance is made for the preferential nucleation of loops orien…
A class of crystalline substances is recognized in which changes of chemical composition are accompanied neither by forming a step-wise succession of phases nor by forming nonstoicheiometric or solid solution phases with disordered, defect structures. Instead, every composition orders into a superlattice and the diffr…
The solvent acid‐base properties of melts containing 50–70 mole per cent at temperatures of 175°–355°C are fully described by the use of three equilibrium constants At 175°C the K values on the mole fraction scale are , respectively. The Δ H and Δ S values for each equilibrium were found to be temperature independent…
Abstract Reduction of insoluble collagens from bone, skin, and tendon with NaB3H4 produced several radioactive substances which were isolated from acid hydrolysates of the protein. One of these substances, aldol-histidine, was most abundant in cow skin collagen and also appeared in reconstituted fibrils of purified co…
The microscopic theories which have been proposed for lyotropic liquid crystals are studied, in particular in connection with the model gas of hard rods. For sufficiently long rods most theories are equivalent to that of Onsager; for shorter rods no theory seems to have a very good claim to accuracy. The theory of Flo…
An oxide film on a metal surface will thicken only if metal, or oxygen, or both, migrate across it. The relative magnitude of the metal and oxygen migrations can be determined using markers, and the possible results are reviewed for the ideal case of a homogeneous oxide grown to uniform thickness on a plane metal surf…
Résumé. 2014 On décrit les propriétés thermodynamiques et les diagrammes T-x de l’équilibre liquide-solide dans les systèmes ternaires II-VI et IV-VI par un modèle de solution régulière asso-ciée, dérivé de celui utilisé par Jordan pour le liquide et dans l’hypothèse d’une solution régulière pour le solide. Pour les s…
Two main systems of approach used to determine if algae can reliably indicate water quality are discussed in this paper. One approach is to observe and analyze natural communities. The effect of a pollutant can be estimated by shifts in species composition and structure of the community in this type of study. The seco…
The dihedral angle between the rings of biphenyl is determined to be 32 ± 2° in the molten and solution states. Observed vibrational frequency shifts on going from the planar configuration held in the crystal to the non-planar solution state are compared with computed frequency shifts. To improve the accuracy in the c…
A detailed study was made of the static ferroelectric properties of a group of (H1-xDx)2 crystals with nominal x values of 0, 0.35, 0.80 and 0.98. The properties investigated included the transition temperature Tc, the Curie constant C, the saturation polarization Ps, the coercive field Ec and the electric field stren…
Description The Symposium on Effects of Radiation on Substructure and Mechanical Properties of Metals and Alloys was presented at Los Angeles, Calif., 26-28 June 1972 in conjunction with the Seventy-fifth Annual Meeting of the American Society for Testing and Materials. The symposium was sponsored by ASTM Committee E1…
A novel experimental procedure combining the measurement of (i) the flow velocity and (ii) the change in birefringence induced by laminar flow in a magnetic field has been used to determine the complete set of the five independent shear-viscosity coefficients of nematic liquid crystals. The anisotropy of the magnetic…
Soil under the crown of mesquite trees was compared to soil from adjacent openings at three depths for several physical and chemical properties near Tucson, Ariz. Bulk density was lower in soil under mesquite but increased with depth in that location. Organic matter, total nitrogen, total sulfur, and total soluble sal…
The behavior of corrosion layers on Pb in solutions is shown to resemble that of perm‐selective precipitation membranes, prepared by interdiffusion of Pb +2 ions and ions into cellophane foil. Diffusion potentials in these precipitation membranes follow, over a wide p H‐range, the equation and can reach values of seve…
PbHPO4 and the deuterated form PbDPO4 are found to be ferroelectric at room temperature with space group Pc. Pyroelectric, dielectric and ferroelectric measurements as a function of temperature show the room temperature values of the spontaneous polarization Ps are 0.72 and 2.1 μC/cm2, for PbHPO4 and PbDPO4 respective…
We deal with the actual position of the system of liquid crystalline modifications. This system is based on the relations of miscibility of the liquid crystalline modifications and on their textures. We describe the method of classification and the main textures of thermotropic liquid crystals. The connection between…