Materials Literature
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The valence isomerization of quadricyclene to norbornadiene is catalyzed by certain transition metal complexes of phthalocyanine and tetraphenyl porphyrin. To explore the dependence of catalytic activity on the number of d-electrons in the metal ion, complexes having a number of d-electrons from 5 to 10 were studied.…
Abstract A convenient pressure apparatus was designed for crystallization of high polymers under hydrostatic pressure up to 5000 atm. Melt crystallization as well as heat treatment under various temperatures and pressures was carried out on several polymers, and the effects of pressure on the molecular and crystal str…
The EPR spectrum of isolated ${\mathrm{Cu}}^{+2}$ ions in NaCl obeys an axial spin Hamiltonian at low temperatures with ${g}_{\ensuremath{\parallel}}=2.373$, ${g}_{\ensuremath{\perp}}=2.07$, ${A}_{\ensuremath{\parallel}}=95$ G, ${A}_{\ensuremath{\perp}}=40$ G, ${Q}^{\ensuremath{'}}=20$ G with the $z$ axis lying parall…
A modified Ramsauer technique has been used to measure the total low-energy scattering cross sections of electrons in ${\mathrm{O}}_{2}$ over an energy range from 2.35 to 21 eV, and in Ne over a range from 0.37 to 20 eV. A broad clearly defined "bump" is observed in the $e\ensuremath{-}{\mathrm{O}}_{2}$ cross section…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal and molecular structure of the barium salt of an antibiotic containing a high proportion of oxygenSuzanne M. Johnson, Jeannie Herrin, Shui Jan Liu, and Iain C. PaulCite this: J. Am. Chem. Soc. 1970, 92, 14, 4428–4435Publication Date (Print):July 1, 1970Publication Hi…
A theory of translational and orientational melting with application to liquid crystals is presented in a manner analogous to that of Kirkwood and Monroe by introducing both translational and orientational order parameters.
Abstract In a continuation of previously reported work of the effect on cotton cellulose of ethyleneurea crosslinking agents modified with ring substituents of varying hydrogen‐bonding capabilities, accessibilities of the cellulosic hydroxylic protons to exchange with deuterium oxide vapor were determined by means of…
A mechanism for relating the redistribution of ions in a periodic stress gradient to internal friction peaks is proposed. The calculated internal friction peak is broad and asymmetric, and the frequency of maximum loss is proportional to the conductivity of the material, as is found experimentally, for silicate glasse…
Abstract Differential thermal analysis has been used to study the fusion of aqueous thermally reversible gels of gelatin and polyacrylylglycinamide (PAG). In the case of gelatin gels, endotherms close to the melting point are readily observed and these are sometimes preceeded by a small exothermic heat of gel reorgani…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal and molecular structure of the acetylacetonimine adduct of ytterbium acetylacetonate, Yb(C5H7O2)3(CH3COCH = C(NH2)CH3)Mary Frances Richardson, P. W. R. Corfield, Donald E. Sands, and Robert E. SieversCite this: Inorg. Chem. 1970, 9, 7, 1632–1638Publication Date (Prin…
The flexural vibrations of ship-like structures are easily excited by underwater explosions, particularly if the explosion bubble period approximately synchronizes with a period of flexural vibration. A summary of the theoretical analysis shows how the transient motions are related to the principal vibration modes of…
Abstract The electron microscope has been used to study the mechanisms of thermal decomposition of kaolinite in the temperature range 800-1350°C. Three main reaction mechanisms appear to be important in this temperature range. At 850°C metakaolinite breaks down to produce an amorphous defect oxide phase which is homog…
The internal-stress-distribution model of magnetomechanical hysteresis is extended to a calculation of the ΔE effect, the irreversible low-field permeability, and temperature-dependent magnetomechanical damping. The calculation of the strain dependence of the ΔE effect agrees well with experimental results for Fe-7.65…
In the triclinic crystals ammonium and potassium tetroxalate dihydrate 34 and 31 sound velocities respectively were measured by means of the diffraction of light by ultrasonic waves. From these velocities the 21 independent components of the elastic tensor were calculated. Thus, the method first tested by Haussühl & S…
Flashover tests were conducted with the cooperation of the Central Research Institute of Electric Power Industry, the Tokyo Electric Power Company, Inc., and the Chubu Electric Power Company, Inc., at the top of Mount Nyũ gasa, 1850 meters above sea level and the Takeyama Laboratory, nearly at sea level, to obtain com…
It has been shown that the Fe 3+ ions in the distorted perovskite GdFeO 3 become ordered antiferromagnetically at 650 K and the ordering arrangement is G x F z in Bertaut's (1963) notation. The canted moment has been measured at temperatures below 77 K, and has been found to produce an effective field of 310 Oe at the…
The Raman spectra of the noncentrosymmetric biaxial sodium nitrite (NaN${\mathrm{O}}_{2}$) single crystal at 77 and 294 \ifmmode^\circ\else\textdegree\fi{}K are presented. No major difference between the two spectra is observed, indicating that the recently reported phase transition at 178 \ifmmode^\circ\else\textdegr…
Summary Alkaline microgranites and granite, containing aegirine, riebeckite and astrophyllite, from north-west Pakistan, are briefly described, and tentatively correlated with other alkaline rocks in the region.
Abstract The usefulness of various techniques for characterizing poorlyordered inorganic gel systems in clays is considered. Many established instrumental techniques are unsuitable, but thermal methods, chemical dissolution techniques, and specific surface reactions are more appropriate. The reaction of fluoride with…
Abstract A rate constant is generally derived by using Fick's equation corresponding to the spherical interdiffusion of particles. By using this rate constant, chain and primary radical termination rate constants can be approximated to rate constants for the bimolecular reactions between two radical chain ends, and pr…