Materials Literature
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The results of two new experiments designed to determine the contact angle of water on ice are reported. In one it is shown that the first stage of melting of a clean ice surface is liquid formation at discrete sites, not uniformly over the surface as would be predicted if the contact angle were zero. The water has a…
The small nephelauxetic parameters dβ for lanthanide heteropolytungstate complexes show that the Ln–O bond is essentially ionic. The absorption spectra of the EuIII complexes indicate, in each case, site symmetry not higher than tetragonal for the lanthanide; the emission spectra of EuW10O357– and Eu(SiW11O39)211– in…
The anodic dissolution of tungsten was studied in solutions and solutions at 25°C. Faradaic efficiency studies in basic solutions showed the metal to be oxidized to the +6 state. In acid solutions, a thick protective film of yellow was formed. Polarization curves possessed linear Tafel regions at potentials slightly m…
The discovery is reported of the first optically active smectic liquid crystal to consist of only one compound and to permit supercooling to room temperature. The compound is bis-(p-6-methyloctyloxybenzylidene)-2-chloro-1, 4-phenylenediamine.
The thermal decomposition of diborane-phosphine mixtures in a hydrogen atmosphere and the thermal reduction of boron tribromide-phosphorus trichloride mixtures with hydrogen have been used for the deposition of boron phosphide on the basal plane of hexagonal silicon carbide substrates. In the thermal decomposition pro…
A theory is developed of the circular dichroism and rotatory power of thin films of cholesteric liquid crystals. It is an extension of the treatment for infinitely thick specimens discussed in a previous paper. The therory predicts that the circular dichroism of a thin film plotted as a function of wave-length should…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfrared studies of adsorption and surface reactions of some secondary alcohols, C3 to C5, on .gamma.-alumina and .gamma.-alumina doped with sodium hydroxideA. V. Deo, Tze-Tang Chuang, and I. G. Dalla LanaCite this: J. Phys. Chem. 1971, 75, 2, 234–239Publication Date (Print)…
Difficulty is found in fitting experimental g values for low-spin ferric haemoproteins to formulae based on a pure t 2 5 configuration. This is discussed and it is shown that it is almost certainly mainly due to neglect of configuration interaction with excited t 2 4 e states, a mechanism which was originally discusse…
The double refraction of 32 liquid crystalline substances and their dependence on temperature and wavelength has been studied. The measurements were made on uniaxially oriented liquid crystalline layers using the principle of Abbé's double prism. Such optically uniaxial layers are obtained from the nematic states and…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhosphorescence microwave multiple resonance studies in determining the radiative and nonradiative properties of the triplet stateMostafa A. El-SayedCite this: Acc. Chem. Res. 1971, 4, 1, 23–31Publication Date (Print):January 1, 1971Publication History Published online1 May…
A method is proposed for the determination of phosphorus in plant material using a modified Kjeldahl digestion and a Technicon Autoanalyzer. The procedure depends upon the formation of phosphomolybdate and its reduction to molybdenum blue by ferrous ammonium sulphate. The method enables the simultaneous determination…
A method is described which enables the direct measurement of relaxation times and relaxed and nonrelaxed heat capacities as a function of temperature. The apparatus designed is to be used as additional equipment to the Perkin-Elmer differential scanning calorimeter DSC-1B. The specimen is heated periodically with tim…
The dissolution into water of anhydrite and gypsum was studied at 25°C using a rotating disc of polycrystalline material, and the kinetics were followed with a calcium selective electrode. The dissolution rate of gypsum was transport controlled while that of anhydrite was intermediate between chemical and transport co…
An electrochemical technique has been developed with which the steady‐state concentration of adsorbed hydrogen on an iron surface, θ, can be determined. By using values of θ determined by electrochemical techniques, a method of evaluating the specific rate constant for hydrogen absorption into iron, k abs , has been d…
Values of the critical breakdown potential, E c for a series of iron‐chromium binary alloys and some commercial stainless steels in aerated 3.5% sodium chloride are presented. The results are correlated with previously published data on the same materials after prolonged exposure to a marine environment. Exact correla…
Flashover of wet polluted insulation is caused by the propagation of arcs along the wet surface. The paper describes experimental work which has been carried out with simple models to investigate the conditions under which arc propagation occurs. It has been found that arc propagation can be explained in terms of a ne…
The electronic spectra of monomeric and dimeric silicon phthalocyanines are described. The spectral differences are interpreted in terms of exciton coupling of neutral-excitation transitions of the two rings of the dimer.
Oligonucleotide cataloguing has been used to characterize a number of 5S RNA species from various Procaryotes. Such catalogs can be used to establish certain and detailed phylogenetic relationships among organisms. Confining attention at present to four Families of Procaryotes, theEnterobacteriaceae, theBacillaceae, t…
The behavior of as positive electrode material in organic solvent batteries has been investigated. This oxide in solutions shows low solubility and satisfactory polarization behavior. Micropolarization tests showed the reversibility of the redox process of in the considered electrolyte. From, the voltage sweep curve a…
Nous avons étudié les propriétés magnétiques de deux substances nématiques (PAA et MBBA). Une nouvelle interprétation du comportement d'une phase nématique placée dans un champ magnétique tournant, jointe à l'utilisation de données obtenues par d'autres techniques nous conduit à proposer de nouvelles valeurs de l'anis…