Materials Literature
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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…
The representation and interpretation of dynamic mechanical properties of heterogeneous polymer–polymer composites are discussed in terms of equivalent mechanical models and the viscoelastic form of the well-known Kerner equation. Model parameters calculated from dispersed phase volume fraction and matrix Poisson's ra…
The properties of charge carriers in solids can be modified greatly by their real and virtual interactions with optical phonons. These effects differ in two particular ways from the changes induced by interactions with acoustic lattice modes. Firstly, those optical modes which interact with carriers are closely monoch…
A variational calculation of the eigenstates of the three-dimensional analogue of Holstein's Molecular Crystal Model is utilized as a basis for determining the conditions under which carrier self-trapping does or does not occur in this system. It is found that below a temperature-dependent critical value of the electr…
The d.c. electrical conductivity of 14% (by weight) sulfonated polystyrene films was measured as a function of temperature from 20° to 60°C in a 25-micron vacuum. Sulfonated films in the silver, cadmium, and methylene blue sorbed forms were prepared for these electrical measurements. Plots of log specific conductance…
An unusual magnesium carbonate hydrate mineral, Mg5 (CO3)4 (OH)2•8H2O, was found as encrustments of snow-white oolitic, botryoidal and reniform aggregates on the weathered surface of the brucite-bearing serpentinites from Yoshikawa, Aichi Prefecture, Japan. The empirical formula is similar to that of hydromagnesite ex…
A description of the apparatus for a new dynamic polarization effect by variation of temperature, and the experimental results obtained, are presented. As described earlier a temperature jump produces a very large enhancement of the dipolar signal (about 10.000) in solid y-picolene due to the dipolar couplings between…
Abstract The rate of release of interlayer potassium from biotite to NaCl and NaCl/sodium tetraphenylboron solutions is determined by the oxidation state of octahedral iron. Octahedral cation vacancies are generated when octahedral iron is oxidized resulting in a change of orientation of hydroxyl from perpendicular to…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics and Mechanism of Carbonation of Magnesium Oxide SlurriesG. L. Smithson and N. N. BakhshiCite this: Ind. Eng. Chem. Process Des. Dev. 1973, 12, 1, 99–106Publication Date (Print):January 1, 1973Publication History Published online1 May 2002Published inissue 1 January…
Crystals of the title compound are monoclinic, space group P21/c with unit cell dimensions: a= 5·64, b= 9·80, c= 6·88 Å, β= 98·8°. The structure, which was determined from photographic X-ray data by Patterson and Fourier methods, consists of a slightly distorted hexagonal close packed array of carbonate ions in which…
The theory of the propagation of light along the axis of a cholesteric liquid crystal is considered. Two models have been used so far, viz., the spiralling dielectric ellipsoid model of Oseen, treated theoretically by de Vries, and the twisted pile of birefringent plates treated according to the dynamical theory by Ch…
In dielectrically positive mixtures of the nematic N4 with cholesteryl-chloride an unusual texture transition was observed which can be applied in a storage effect. The variation of several characteristic parameters of these mixtures with concentration and temperature was measured.
The present paper deals with the description of 60 pollen and spore species found in Palaeocene sediments of the Chubut Province, Argentina. The material was collected from several sections of the Salamanca Formation (Cerro Abigarrado, Puerto Visser, Bajada de Hansen) and from other sections of the Bororo Formation. A…
Experiments were conducted with pitting corrosion of the ends of titanium rods insulated on the sides with epoxy resin. The rods were potentiostated in the anode‐facing‐up position in chloride, bromide, and iodide solutions. After a small depth of corrosion a uniform current density was obtained characteristic of one‐…
A survey is given of electric alignment in liquid crystals, emphasizing electro-optical effects and the physics behind them.
When iron–vanadium–carbon alloys are transformed from the γ to the α state, a banded dispersion of vanadium carbide is formed as the transformation fronts move through the crystals. The strengthening resulting from this reaction in a series of alloys isothermally transformed in the range 725–850° C is shown to be depe…
The paper discusses the dependence of γ-the coefficient of potential emission of electrons from metals on the work function ϕ and Fermi energy εF for metals and the ionization energy of ions Ei . It has been found that in the range 3ϕ <Ei<2(∊F+2ϕ) Deviations from this dependence exceeding 10% have been observed at Ei<…