Materials Literature
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The temperature dependence of the complex dielectric constants at 9.2 Gc/sec are reported for a series of partially deuterated potassium dihydrogen phosphate crystals as well as for a potassium dihydrogen arsenate and an ammonium dihydrogen phosphate crystal. The transition temperature, the high-temperature loss tange…
The assignment of the normal-mode spectrum in perovskites has been achieved by a comparison of the vibrations of calcium, strontium, barium, and lead titanates and zirconates. In addition, for the antiferro-electric material lead zirconate, about 90% of the value of the low-frequency dielectric constant is the result…
The effects of data termination and systematic errors on the radial distribution functions of liquids obtained from x-ray diffraction data are investigated with the aid of a computer. A general procedure for the elimination of spurious detail is presented, and new data for liquid mercury and lead are analyzed. Compari…
It is shown that the existence of an orbital degeneracy in the $3d$ band may lead to a change of sign of the magnetostriction, when this degeneracy goes through the Fermi level. Such a change of sign is observed in the Fe-Ni and Co-Ni alloy series (permalloy), at an electron concentration of 27.7 electrons per atom. A…
Piezoelectric paramagnetic crystals can show a linear dependence of the paramagnetic susceptibility on an applied electric field. This effect has been detected in NiS${\mathrm{O}}_{4}$\ifmmode\cdot\else\textperiodcentered\fi{}6${\mathrm{H}}_{2}$O at low temperatures. The thermodynamic inverse effect, the creation of a…
The electrical resistivity $\ensuremath{\rho}$, the Seebeck coefficient $Q$, and the thermal conductivity $\ensuremath{\kappa}$, were measured in a series of GaAs samples in the temperature range 300-900\ifmmode^\circ\else\textdegree\fi{}K. Values of $Q$ were combined with room-temperature values of the Hall coefficie…
The Madelung constants for the 4–4, 3–5, 2–6, and 1–7 tetragonal perovskite structures have been calculated for axial ratios α=c/a varying from 0.90 to 1.10. Least-squares fits expressing the Madelung constant as a function of (1—α) are reported.
The 11B1H molecule of Σ+ symmetry is predicted, on the basis of perturbed Hartree—Fock calculations in which the origin is chosen at the B nucleus, to have a magnetic susceptibility of 18.16 ppm (paramagnetic!), a rotational magnetic moment of −8.17 μN, shielding constants at B of −264 ppm and at H of 22.6 ppm, and sp…
Electron paramagnetic resonance studies of the tetrahedral CuCl4= ion in single crystals of Cs2CuCl4 and Cs2ZnCl4 yield the spectroscopic parameters g1=2.083±0.001, g2=2.103±0.003, g3=2.384±0.006 (Cs2CuCl4) or 2.446±0.002 (Cs2ZnCl4), and | A1 | = (5.1±0.5)×10−3 cm−1, | A2 | = (4.6±0.5)×10−3 cm−1, and | A3 | = (2.5±0.5…
From simple considerations of the different ways in which ammonia may be introduced into the structures of metal ammine salts it is evident that while the ammonia molecules tend to be coordinated to the metal ions they otherwise behave as rather inactive groups towards their remaining environment. Accordingly a factor…
The metastable form of acetamide has been studied by X-ray diffraction. The crystals are orthorhombic, space group Pccn, a=7"76, b= 19.00, c= 9"51/~, Z= 16. There are two molecules in the asymmetric unit. These are bound in two-molecule units by a pair of hydrogen bonds. Further hydrogen bonds link these dimers togeth…
The chemistry of the reactions which occur between polyisocyanates and ancillary raw materials for the manufacture of polyurethanes is described and discussed. The four principal fields of activity in which urethanes find application are (1) flexible foams; (2) rigid foams; (3) surface coatings, and (4) rubbers. It is…
The die le ctric co nstant and loss of glassy B20 3 have been measured from 500 to 800 O( ove r th e fr e qu e ncy ra nge 1 to 50 kHz. The mate rial be haves esse ntially lik e a nonpolar po l yrr;e~; no re laxatI on phenomena could be identified. Ove r th e e ntire fre qu e ncy and te mperature ran ge LI es betwee n…
Abstract Tensile fatigue failure of a gum vulcanizate of noncrystallizing SBR can be accounted for by the growth of small flaws initially present in the rubber. Fatigue of crystallizing natural rubber was shown in Part I to be attributable to the same cause. Cut growth results are interpreted in terms of the tearing e…
Abstract Poly(vinylidene fluoride), polytrifluoroethylene, and two rubbery copolymers with vinylidene fluoride were crosslinked by γ‐irradiation in vacuum. Radiation‐induced chain scissions in the copolymers were studied by observing the relaxation of stress at constant extension during further irradiation at 27°C., a…
The crimp in all-cotton, nylon, and polyester/spandex core stretch fabrics was ex amined by physical tests and by photographic enlargements of yarns and fibers removed from the fabrics. Measurements of total crimp and crimp due to yarn crossover indicate that yarn crossover crimp, external yarn crimp, has a major infl…
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The motion of edge and screw dislocations in a graphite polycrystal subjected to external forces and fast neutron irradiation is considered. A transient creep strain, proportional to the external stress and proportional to the ratio of the dimensions of the component crystallites in the a and c directions, is deduced.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermodynamics of Metal Cyanide Coordination. IV. Log βi°, ΔHi°, and ΔSi°, Values for the Zinc(II)-Cyanide System at 25°Reed M. Izatt, James J. Christensen, James W. Hansen, and Gerald D. WattCite this: Inorg. Chem. 1965, 4, 5, 718–721Publication Date (Print):May 1, 1965Publ…
Superpurity aluminium specimens subject to reversed cyclic torsion extend axially by accumulation of second-order plastic strain increments. These arise in quasi-isotropic strain-hardening metals because of the additional quadratic term in the stress-strain relation that is required by the condition of tensorial invar…