Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation and anodic peak potentials of salts of coordination compounds derived from boric acid and polyhydric phenolsManuel Finkelstein, Edward A. Mayeda, and Sidney D. RossCite this: J. Org. Chem. 1975, 40, 6, 804–805Publication Date (Print):March 1, 1975Publication Hist…
H atoms, which have been generated in the gas phase, have been allowed to interact with palladium metal and several of its substitutional f.c.c. alloys. It has been found that quite high concentrations of interstitial hydrogen can be introduced in this manner even in the absence of poisons such as H 2 S. The kinetics…
The infrared spectra of the vapors over alkali metal perchlorate salts at temperatures in the 400−450° range have been measured by isolation of molecular beams of the vapor species in various matrices at 12°K. The data indicate that at these temperatures the dominant vapor species are the monomeric ion pairs, M+ClO−4,…
Abstract Les composés K 3 VO 4 , K 3 CrO 4 et K 3 MnO 4 existent sous deux formes allotropiques isotypes respectivement de K 3 Cr(O 2 ) 4 et de Na 2 CaSiO 4 . Des mesures magnétiques confirment le degré d'oxydation +V du chrome et du manganèse.
The moth’s eye principle of optical-impedance matching by means of an array of tapered protuberances has been studied to determine the limit obtainable for reflection reduction. Analogous multilayer equivalents were optimized over a wide band, using a recently developed optimization method, in which one or more of the…
The kinetics of the K + ⇌ Na + exchange in Na 2 O·3SiO 2 glass at 350°C were studied. The distribution of K in the glass specimens after exchange in molten KNO 3 was determined with an electron microprobe. The calculated interdiffusion coefficients, which varied with the local composition in the glass, were compared w…
Digital clipped auto correlation spectroscopy was used to investigate the kinetic features of thermodynamic fluctuation processes which relax on time scales from 10 −6 to 10 2 s. The autocorrelation function associated with structural relaxation in Na 2 O· K 2/ O·6SiO 2 , glass was determined in the annealing region.…
The present status and prospects of the laser flash method for the measurement of thermal properties of nuclear materials are reviewed. Special emphasis is placed on the progress seen in experimental techniques for obtaining precise data on heat capacity and thermal diffusivity from 80 to 1,000 K. In this temperature…
Simple geometrical considerations predict 3 types of tilt grain boundaries in smectics A : curvature of the layers, arrays of dislocations and focal domains of equal eccentricity. These 3 possibilities are shown to exist in CBOOA (shear experiment). Their energies are discussed in terms of a simple model.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis, characterization, and bonding of tetrameric triphenylphosphine silver halide cluster systems. Evidence of dictation of stereochemistries by van der Waals interactionsBoon-Keng Teo and Joseph C. CalabreseCite this: J. Am. Chem. Soc. 1975, 97, 5, 1256–1257Publicatio…
Abstract The purpose of this study was to investigate contact nucleation for various types of crystalline materials. Selected were aqueous solutions of two hydrated inorganic salts (MgSO 4 · 7H 2 O and KAl(SO 4 ) 2 · 12H 2 O), one nonhydrated inorganic salt (K 2 SO 4 ) and one organic substance (citric acid). Nucleati…
Gamma-ray buildup factors in ordinary concrete have been calculated by the moments method. Results for concrete kerma and air kerma are tabulated for source energies from 15 MeV to 15 keV. Parameters are given that allow calculation of the buildup factor by means of a simple analytic expression. Comparisons are made w…
If two metal plates are brought together at a sufficiently high relative velocity, a jet may form which removes much of the surface impurities, and a strong bond occurs. The purpose of this paper is to decribe the formation of a wave interface, and to suggest why a bond often occurs without the appearance of such wave…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics of the thermal decomposition of methyldisilane and trisilaneA. J. Vanderwielen, M. A. Ring, and H. E. O'NealCite this: J. Am. Chem. Soc. 1975, 97, 5, 993–998Publication Date (Print):March 1, 1975Publication History Published online1 May 2002Published inissue 1 March…
High-resolution single-crystal electron diffraction intensity data from fully hydrated, flat, rectangular catalase microcrystals are subjected to various tests which support the thesis that diffraction from crystals with thicknesses up to at least 1500 Å may be treated by the kinematical theory. The ratio of the total…
Abstract α-Ba2SiW12O40·16H2O is monoclinic, space group C2/c, with a=25.09(5), b=12.10(2), c=18.79(3) Å, β=122.5(3)°; Dm=4.95 g cm−3 and Dx=4.78 g cm−3 for Z=4. The crystal consists of the well known Keggin ion SiW12O404−, having a SiO4 tetrahedron in the center, bound by Ba2+ and water molecules to form a three-dimen…
Abstract The morphology of several series of segmented polyether–urethanes was studied. The “hard” segments contained urethane and urea linkages formed by 4,4′‐dicyclohexylmethane diisocyanate (Hylene W) and selected aliphatic and aromatic monomeric diamines (DA). The “soft” segments were composed of oligomeric poly(e…
The structures of {112} twin boundaries in body-centred cubic crystals have been studied using computer simulation methods and interatomic potentials representing iron, molybdenum and tungsten. Two distinct structures were found to be stable or metastable in the models used. These were the conventional twìn boundary d…
Abstract Recent work is presented on the plastic deformation of linear polyethylenes. This work demonstrates the importance of molecular weight and initial morphology in determining the drawing behavior, and shows that by appropriate choice of these two factors a substantial increase in draw ratio and hence stiffness…
A neutron-scattering study has been carried out on magnetite at temperatures just above the Verwey transition point of ${T}_{V}=123$ K. No critical scattering was observed at the (0,0,2) reciprocal-lattice point where the magnetic scattering appeared below ${T}_{V}$ due to the Verwey ordering as previously reported by…