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Abstract Double oriented fiber spectra of syndiotactic polypropylene were obtained. It was possible to redetermine with greater accuracy the unit cell constants, which are: a = 14.50, b = 5.60, c = 7.40 A. Space group: C222 1 . It was proved that the chain has s (2/1)2 symmetry, corresponding to a succession of intern…
The spin-lattice relaxation of paramagnetic ions in ionic crystals takes place via thermal modulations of the complex consisting of the ion and its immediate neighbours. The standard theory is that due to Van Vleck, who used a crystal-field model to describe the complex. In recent years there have been extensive devel…
The EPR and optical spectra of vanadium in the Na2O–B2O3 glass system have been analyzed. It is found that the data can best be interpreted in terms of a vanadyl-type structure in a ligand field of fourfold symmetry. Good correlation of the optical and EPR data is achieved through molecular orbital calculations, which…
This paper deals with the algebraic classification of non-euclidean plane crystallographic groups (NEC groups, for short) with compact quotient space. The groups considered are the discrete groups of motions of the Lobatschewsky or hyperbolic plane, including those which contain orientation-reversing reflections and g…
The d‐c polarization technique according to Wagner was applied for the first time at elevated temperatures for the determination of σ ⊖ and σ ⊕ in the Zr 0.85 Ca 0.15 O 1.85 and Th 0.85 Y 0.15 O 1.925 electrolytes over a range of oxygen activity and temperature. The applicability of the technique and an improved metho…
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In semiconductors having high efficiency for radiative recombination, the voltage dependence of cathodoluminescence may be used to determine the diffusion length and to estimate the surface recombination velocity of excess carriers. Theoretical calculations are based on a knowledge of the Laplace transform of the dist…
Abstract Elastic moduli of the crystalline regions in high polymers have been studied. Oriented specimens were used throughout. Lattice strains were measured by an x‐ray technique in the direction of the fiber axis as well as in that perpendicular to the fiber axis. The moduli for both directions were calculated on th…
The kinetics of the reactions of various glasses with water and aqueous solutions with pH from 1 to 13 was studied. Simple binary alkali oxide‐silica glasses were examined as well as some ternary glasses derived from the binary compositions by substituting alkaline‐earth oxides for silica. All components of the glass…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT5T2-1A1 Equilibriums in some iron(II)-bis(1,10-phenanthroline) complexesEdgar Koenig and K. MadejaCite this: Inorg. Chem. 1967, 6, 1, 48–55Publication Date (Print):January 1, 1967Publication History Published online1 May 2002Published inissue 1 January 1967https://pubs.acs.o…
Abstract Complex moduli of oriented specimens of polyethylene (PE), polypropylene (PP), polyoxymethylene, polyethylene oxide), and polytetrahydrofuran were measured in sheet form as a function of direction. The dynamic tensile modulus (E′) along the stretched direction (0° direction) was found to be lower than that pe…
Examination of benzotriazole-treated surfaces on copper, and the complexes produced when benzotriazole and analogous compounds react with cuprous and cupric ions in aqueous solution, has shown that the film produced on copper has a polymeric structure and is chemically bonded to the metal or metal-oxide surface Thickn…
Abstract The resonant secondary radiation spectrum of impurity centres in crystals is studied on the basis of a second‐order approximation for the interaction between the electromagnetic field and the material. It is shown that for the case of excitation in the phonon wing of the absorption band, the main part of the…
Abstract Der Selbstdiffusionskoeffizient D und die longitudinale Kernspinrelaxationszeit T 1 der Protonen wurden in der flüssigen Phase zwischen Schmelzpunkt und Siedepunkt von Molekülen des Typs (CH 3 ) 4 X, mit X = C, Si, Ge, Sn, Pb, (CH 3 ) 3 CX mit X = Cl, Br, J, OH, NO 2 , (CH 3 ) 3 SiX mit X = Cl, Br, Fund (CH 3…
Abstract Les produits obtenus à partir d'une méthode simple de préparation des éméraldines out été étudiés en ce qui concerne leurs propriétés d'acidité, d'oxydo‐réduction et de formation de complexes: ( 1 ) l'analyse des courbes de neutralisation de suspensions aqueuses d'éméraldines par des bases fortes a permis d'é…
Abstract The sorption and the desorption isotherms of water are described for several crystalline polyamides (nylons 2, 3, 6, 7, 8, 11), amorphous polyamides (poly‐ C ‐methylcaprolactam, terpolymer of caprolactam, aminoheptanoic acid and aminoundecanoic acid) and model amides ( N ‐ethyl acetamide, Y ‐ethyl butyramide,…
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Energy transfer studies employing the sodium rare earth tungstates (scheelite structure) indicate a number of modes of, and requirements for, nonradiative interaction. Direct dipole‐dipole interactions are prevalent. However, dipole‐quadrupole interactions are observed for the states of the larger rare earth ions that…