Materials Literature
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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…
The general form of the energy of interaction between two asymmetric molecules is considered. This leads to a generalization of the Maier-Saupe model of a nematic liquid. The exact state of minimum internal energy of the system is found to be biaxial. In the molecular field approximation the consistency relations yiel…
High-voltage insulators may flashover at working voltage when polluted and wet. Pollution is deposited by various forces, of which aerodynamic ones are shown to be usually the most important. Theories to explain the pollution-flashover process are described. The performance of insulators in a polluted environment may…
The structure of nitrosylpenta-amminecobalt(III) dichloride, [Co(NO)(NH3)5]Cl2, has been redetermined by use of three-dimensional X-ray data collected by counter methods. The compound crystallizes in the orthorhombic space group D2h17–Cmcm, with a=c= 10·459(7) and b= 8·753(6)Å. Each crystal grows as an intimate twin,…
Abstract A synthetic polycrystalline sample of Ni(OH)2 was investigated by means of neutron diffraction in the temperature range 4.2 to 293 °K. The crystallochemical structure of this compound is analogous to the structure of Ca(OH)2. At temperatures below 28 °K Ni(OH)2 is antiferromagnetic with magnetic moments direc…
A series of uni–ter-valent electrolytes of general formula [Au9L8]X3 has been prepared and characterized; preliminary X-ray structural results are reported for the salt [Au9{P(C6H4-p-Me)3}8][PF6]3.
For interpreting the optical properties of aggregated metal films, a modification of Schopper’s model is proposed, based on the assumption that an aggregated film consists of particles in the shape of rotational ellipsoids. Instead of the distribution of the depolarizing factor f in gaussian fashion, which is assumed…
The sound velocities (elastic moduli) of ${\mathrm{V}}_{3}$Ge and ${\mathrm{V}}_{3}$Si are found to have very large discontinuities in their temperature derivatives at the superconducting transition. A thermodynamic treatment of these data (with the specific-heat behavior) for a second-order phase transition is shown…
The crystal structure of the C form of stearic acid has been determined from X-ray powder diffraction patterns, The crystals are monoclinic, space group P21/a, with unit-cell dimensions: a= 9·36, b= 4·95, c= 50·7 Å. β= 128 °15′ and Z= 4. The crystal structure has been determined by trial-and-error methods to R 0·086.…
Previous investigations on Cu ‐ Au and Cu ‐ Zn alloys have shown that the polarization curves for anodic dissolution of the less noble metal are complex, that the mechanism of preferential anodic dissolution involves the interdiffusion of the components in an alloy layer next to the surface, and that appreciable surfa…
A numerical calculation is described which determines the blocking radius of a pile-up of negative edge dislocations to a group of either negative or positive edge dislocations with the same Burgers vector. The results are used to calculate the work-hardening rate in stage II of face-centred-cubic single crystals in t…
Spectra of the alkali metal intercalation products of MoS2 and NbSc2 arc interpreted in terms of a previously published band model.
The adhesion obtained from a chrome alum-gelatin solution has been found far superior to results given by widely used general adhesives (Haupt's gelatin and Mayer's egg albumen) for paraffin sections. The subbing solution, which consists of 5.0 gin gelatin and 0.5 gm chrome alum per liter of water, is easier to apply…
The decomposition of methyl alcohol on ZnO was studied using infra-red spectroscopy during the course of the reaction. The concentrations and reactivities of the chemisorbed and gas phase species were measured as well as the overall reaction rate under various non-stationary conditions. When CD3OD vapour was introduce…
Selective etching of GaAs in the H 2 SO 4 ‐ H 2 O 2 ‐ H 2 O system was studied as a pretreatment to selective deposition. Flat‐bottomed holes were obtained in low H 2 SO 4 solutions, whereas nonplanar holes were obtained in high H 2 SO 4 solutions. Differences between both cases are considered from the etching behavio…