Materials Literature
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A method and technical details are described for direct observation of effects of high amplitude ultrasonic stress waves on dislocations in metal crystals. The technique combines, for the first time, ultrasonic treatment at high acoustic energy densities (up to 109 ergs/cm3 at frequencies between 30 and 100 kc), obser…
Inter-fibre frictional forces, F, corresponding to normal loads, R, of up to 300 g, experimentally determined for a large number of fibres, mostly cottons, rayons, and polynosic rayons, conform to a general expression of the form F = αRn . The parameters α and n are, however, shown to be interdependent, correlations a…
Major characteristics of observed effects of uniaxial compression upon magnetization of rocks and assemblages of magnetic minerals are summarized as follows: -(a) uniaxial compression in a magnetic field results in a decrease of magnetization; (b) removal of the magnetic field in presence of the compession causes a de…
electrostatic forces. The repulsions terms amount to about 10-15% of the lattice energy and cannot be neglected. It should be pointed out the variation of the oxygen parameter has not been taken into account as has already been done by Verwey, de Boer & van Santen (1948), who already give the energy values for 1 and 2…
Abstract Specific heat studies of polymers are reviewed within the framework of Buyer's classification: ( a ) melting transition ( T m ); ( b ) glass transition ( T g ); ( c ) subglass relaxation ( T < T g ); and ( d ) intermediate relaxation ( T g < T < T m ). The melting transition is readily apparent in sp…
The α-chloro-, αγ-dichloro-, and αβγδ-tetrachloro-derivatives of octaethylporphyrin have been prepared by direct halogenation of the porphyrin. Chlorination of octaethylchlorin gives the corresponding γ-chloro- and γδ-dichloro-chlorins; dehydrogenation of the former with 2,3-dichloro-5,6-dicyanobenzoquinone leads to α…
R. G. J. Strens, Chem. Commun. (London), 1966, 519b DOI: 10.1039/C1966000519B
The passivation of a zinc electrode has been studied both by galvanostatic and potentiostatic methods in boric acid-sodium hydroxide buffer solutions. After addition of chloride ion, the characteristics of pitting corrosion have been investigated. The results indicate that pits form only on a passive surface and that…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Spectrophotometric Study of the Nd3+-NO3- Association1Nathan A. Coward and Robert W. KiserCite this: J. Phys. Chem. 1966, 70, 1, 213–217Publication Date (Print):January 1, 1966Publication History Published online1 May 2002Published inissue 1 January 1966https://pubs.acs.or…
The inhibition of the corrosion of iron in alkaline solutions is due to the anodic formation of a film of a ferrous compound, which is usually ferrous hydroxide, but in the presence of anions yielding less soluble ferrous salts, e.g. carbonate, the composition may be mixed. The ferrous compounds are subsequently oxidi…
The crystal structure of silver nitrate has been elucidated from an X-ray analysis. The crystals are orthorhombic, a= 6·997, b= 7·325, c= 10·118 Å, z= 8, space group Pbca (D2h15). Silver atoms lie essentially in planes parallel to (010) and separated by b/2. These planes are linked by the symmetry-related nitrate grou…
Stress-fields around piled-up groups of dislocations of arbitrary orientation have been calculated by replacing the discrete dislocations by a continuous distribution of infinitesimal dislocations. Previous calculations by Mitchell (1964) have been performed on edge and screw dislocation pile-ups. In the present paper…
The degree of normal segregation, occurring during directional (normal) freezing in a transverse magnetic field of 34 000 oersteds, has been determined for aluminium–copper alloys solidified for rates of [Formula: see text] to 4 inches per hour. For ingots in the composition range 0.5% < %Cu < 4.5%, solidified a…
Liquid crystal mixtures were sandwiched between two transparent electrodes on glass and a direct or alternating potential was applied. The light scattering property of the liquid crystal changes upon application of voltage, the intensity varying from 1 to 10% of that scattered by a MgO diffuse surface. The maximum inc…
Étude spectrophotométrique de l'absorption bleue et violette de Cu2O aux températures de l'azote et de l'hélium liquides. On a pu évaluer le facteur d'intensité d'oscillateur des raies bleues et violettes et attribuer le spectre à des transitions excitoniques de première classe.
Abstract The photoconductivity and carrier mobilities of synthetic crystals of realgar (As 4 S 4 ) have been investigated. A sharp increase in the photoresponse at short wavelengths is attributed to an energy gap of (2.40 ± 0.05) eV. An additional weak peak in the photoresponse at 600 nm is due to free hole formation…
Abstract The anisotropy field strength H K is measured in thin nickel and 81/19 nickel‐iron films immediately after deposition and during subsequent systematic annealing in external magnetic fields. These measurements are performed with the films kept in ultra high vacuum using a planar Hall effect method. An analysis…
Abstract The thermally induced solid‐state polymerization of 66 nylon was investigated. It was found that the rate‐controlling step in the process is chemical reaction. A mechanism of the form, rate = kt n was shown to hold. The reaction rate constant was found to be k = 1.53 × 10 10 exp [ − 12,960/ RT ]. Units of k a…
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Abstract Es werden experimentelle Ergebnisse über die thermischen und strahleninduzierten Phasenumwandlungen sowie über die Verschiebung der Umwandlungstemperaturen zwischen den Raum‐ und Hochtemperaturphasen von BaTiO 3 , PbZrO 3 und PbTiO 3 bekanntgegeben. Es wurden vorwiegend röntgenographische und kalorimetrische…