Materials Literature
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The lattice dynamics of the perovskite-type ferroelectric KTa${\mathrm{O}}_{3}$ has been studied by inelastic neutron-scattering techniques. In particular, the temperature dependence of the soft ferroelectric mode, namely a transverse optical mode at $q=0$, has been studied between 4 and 295\ifmmode^\circ\else\textdeg…
Conductivity, Hall-effect, and Seebeck-coefficient measurements on single-domain crystals of $n$-type BaTi${\mathrm{O}}_{3}$ are described. In the cubic phase above 126\ifmmode^\circ\else\textdegree\fi{}C, the electron mobility is 0.5 ${\mathrm{cm}}^{2}$/V sec. When the material becomes tetragonal, the mobility perpen…
The rates of radiative and nonradiative decay were determined for several excited states of ${\mathrm{Er}}^{3+}$ in La${\mathrm{F}}_{3}$ from calculated spontaneous emission probabilities and measured lifetimes. Electric-dipole, magnetic-dipole, and electric-quadrupole transition probabilities were evaluated using int…
A general method of obtaining many-electron wave functions which are eigenfunctions of ${\stackrel{^}{S}}^{2}$ and which also satisfy Pauli's principle is developed. This method is based on the properties of the irreducible units of the group algebra of the symmetric group. Using this method, expansions of the exact w…
Abstract The thermal conductivity of crystals of holmium ethylsulphate has been measured in the range 1 to 4·25°K in zero magnetic field and also in fields up to 53 kG, applied parallel to the hexagonal axis. The change in the thermal resistivity in a field is characterized by two maxima separated by a local, temperat…
Abstract The interpretation of X-ray and neutron diffraction data in accurate studies of crystal and molecular structure requires the development of a new structure factor formalism. The formalism normally employed in structure analysis fails to recognize antisymmetric features associated with nonspherical atomic char…
Single-crystal foils of the compound Bi2Te3 were irradiated with 7.5-MeV protons at two levels of flux to the same integrated dose of 5.5×1018 protons/cm2. The specimens were examined by transmission electron microscopy. After irradiation with a flux of 1.8×1013 protons/cm2·sec, clusters of point defects ranging in si…
X-ray powder diffraction data are reported for 15 normal long-chain esters. The compounds represent all combinations of acid and alcohol where the acid portion is n-tetradecanoic, n-hexadecanoic, or n-octadecanoic acid, and the alcohol portion is n-tetradecanol, n-pentadecanol, n-hexadecanol, n-heptadecanol, or n-octa…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics of decomposition of chloroformic acid by rapid-scan infrared spectroscopyReed J. Jensen and George C. PimentelCite this: J. Phys. Chem. 1967, 71, 6, 1803–1808Publication Date (Print):May 1, 1967Publication History Published online1 May 2002Published inissue 1 May 19…
The thermal expansion of a number of cubic refractory compounds of thorium was measured by high‐temperature X‐ray diffraction. The coefficients of thermal expansion range from 7.5 to 8.2 × 10 −6 /°C for ThN, ThC 0.84 , ThP 0.71 , ThP 0.61 , and Th 3 P 4 between 900° and 1300°, 1450°, 1750°, 1750°, and 1150°, respectiv…
Abstract Polymerization of chloro‐ and fluorobenzene by aluminum chloride‐cupric chloride produced highly colored oligomers. Chlorobenzene reacted under the standard conditions, i.e., 6/1/0.5 (molar ratio) of aromatic/catalyst/oxidant at 60°C. for 1 hr., to give a red solid in 14% yield. Evidence concerning the struct…
The permeabilities of several types of plastic films to water and to carbon dioxide were measured. No material was found to have a carbon dioxide permeability as great as its water permeability.
Abstract Copolymerization of vinyl and divinyl monomer is a typical method for preparing a network polymer. A multiple network structure, in which one network entangles with another, is supposed to be produced when a network polymer is swollen in the monomer mixture and then polymerization of absorbed monomer is carri…
It is emphasized, that the loss of long range order does not necessarily destroy three-dimensional lattices. Nematic or smectic mesophases as well as special types of liquid crystals, many crystalline or amorphous high polymers, crystals near the melting point, molten substances and mixed crystals are examples in natu…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLuminescence of iridium(II) chelates with 2,2'-bipyridine and with 1,10-phenanthrolineKenneth R. Wunschel and William E. OhnesorgeCite this: J. Am. Chem. Soc. 1967, 89, 11, 2777–2778Publication Date (Print):May 1, 1967Publication History Published online1 May 2002Published i…
By twisting copper single crystals to introduce known densities of forest dislocations, the tension yield stress has been related to the forest density in the form: where τ00 ≃ 5g/mm2 and α0 ≃ 0·65. The “small value of τ00 suggests that the yield stress is determined mainly by the forest dislocation density.
Abstract Castor oil has been used to prepare millable elastomers by using 2,4‐toluene diisocyanate, 4,4′‐diphenylmethane diisocyanate, and 1,5‐naphthalene diisocyanate, respectively. These elastomers are vulcanized with sulfur and 4,4′‐diphenylmethane diisocyanate separately by using the standard methods of rubber tec…
The merits of a multi-layer sandwich technique for explosive shock loading of metal foils are discussed with special reference to electron transmission studies of microstructure. The conditions are given for the design of the explosive test assembly such that the foil specimens are subjected to a plane compression wav…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUltrahigh pressure-high temperature synthesis of rhombohedral dichalcogenides of molybdenum and tungstenMeyer S. SilvermanCite this: Inorg. Chem. 1967, 6, 5, 1063–1064Publication Date (Print):May 1, 1967Publication History Published online1 May 2002Published inissue 1 May 19…
Abstract Effects of a naphthenic oil and of HAF carbon black on SBR processability were evaluated. Three rheological parameters related to processability are apparent viscosity, extrudate swell and extrudate surface roughness; they were studied with a capillary rheometer over a shear rate range of 10 to 3000 sec −1 .…