Materials Literature
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Abstract Low temperature heat capacities from 1.5 to 15 K have been measured for a number of transition metal borides with the compositions Me 2 B, MeB and MeB 2 , and their solid solutions. The measurements show that the borides are characterized by a narrow d-band with a relatively large density of electron states.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStudies of surface reactions of nitric oxide by isotope labeling. II. Deuterium kinetic isotope effect in the ammonia-nitric oxide reaction on a supported platinum catalystKlaus Otto, Mordecai Shelef, and Joseph T. KummerCite this: J. Phys. Chem. 1971, 75, 7, 875–879Publicat…
Abstract A study was made of polyimides based on pyrazinetetracarboxylic dianhydride (PTDA) plus heterocyclic diamines different from the one previously reported by Hirsch. It was postulated that thermal properties might be improved if the diamine portion did not contain the N–N linkage. The results indicate that thes…
Using the atom-beam recoil technique, absolute total cross sections were measured for the scattering of electrons in the energy range 0.3-9 eV by potassium, rubidium, and cesium. The results of these measurements are in substantial disagreement with the experimental values of Brode, obtained more than 40 years ago. On…
Copper single crystals orientated for single glide were deformed in tension at 78°K and irradiated before load-removal with fast neutrons at 4°K or 20°K. The dislocation arrangement which was thus stabilized in the stress-applied state was investigated extensively by transmission electron microscopy and compared with…
Raman spectra of the rutile and high-pressure orthorhombic (TiO2 II) phases of titanium dioxide have been studied at pressures as high as 40 kbar. The frequency of the B1g mode of rutile has an unusual negative pressure dependence, dυ / dp = − 0.3 ± 0.1 cm−1·kbar−1. Onset of the rutile:TiO2 II transition is observed a…
An experimental and analytical investigation of the kinetics of formation of NO in shock-induced combustion of hydrogen-oxygen-nitrogen mixtures has been carried out. In the experimental study, concentration lime-histories of NO, OH and H20 were measured during reaction using spectroscopic techniques. Experimental con…
Five homologous series (methyl to n-decyl) of n-alkyl 4-p-substituted-benzylideneaminocinnamates with p-substituents = CN2, NO2, MeO2 MeCO.O and Ph have been prepared and the liquid crystalline properties established. The relative thermal stabilities of the mesophases of the esters with different p-substituents are in…
The design and construction of a double focusing uniform field magnetic electron spectrometer are described. The pole pieces of the magnet are curved in an effort to correct all median plane aberrations and thereby increase the collecting power. The spectrometer has been installed on a scanning microscope which uses a…
ATTACKING aircraft in the first world war used to fly in low, drop their bombs by hand over the cockpit side and be considered unlucky if a rifle bullet came anywhere near them.
The rare occurrence of inactive catalyst gauzes for no obvious reason has led to comparative studies of the structures of rhodium-platinum wires from both active and inactive gauzes. Active gauzes showed the regular development of octagonal crystal faces on the nodular growths on the wires. Inactive gauzes showed no c…
Fiber optics for telecommunications applications require very high purity glass. Light loss in glass results primarily from absorption and scattering. Transition metal ions and OH ions cause most of the absorption, whereas scattering is caused by microheterogeneity. Scattering losses vary from 1 to 4 dB/km at 850 nm;…
The 3-tube symmetrical electrostatic unipotential lens was analyzed in great detail. Starting from a mathematical expression for the axial potential distribution, the cardinal points and coefficients of spherical and chromatic aberration were obtained with the help of a digital computer. Values for S/R, the separation…
The ignition temperature of ten common non-toxic metals has been determined experimentally in an oxygen environment. In this investigation a induction furnace facility that emphasized the pre-ignition surface oxidation effects upon the ignition temperature was used. The bulk ignition temperatures of barium, bismuth, c…
ZnIn2S4 single crystals, grown from the vapor phase by iodine transport, display interesting current-voltage characteristics at high electric fields. Some crystals under illumination show an n-type negative-resistance effect. However, in other crystals which do not show such an effect, current oscillations occur whose…
Diffraction studies of samples of Vitromet, small glass spheres with a metallic coating, show that the surface deposit consists of very small crystallites (~100 Å) in which the internal stress is of the same order of magnitude as the ultimate tensile value. Using rapid methods of data collection and approximate proced…
A sequence of total energy distribution curves for field emission was experimentally obtained for a tungsten emitter heated to 1570 K. Theoretical curves using the Miller-Good WKB-type approximation for tunneling probabilities are in good agreement with the experimental measurements. A significant feature of both sets…
The Raman spectrum of an oriented single crystal of CaSO 4∙ 2H 2 O has been recorded from 20 to 3600 cm −1 at 300 °K and 77 °K using polarized laser excitation. The symmetries of the observed Raman lines have been determined and the spectrum has been analyzed in terms of external lattice vibrations, internal vibration…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure of Ba2MnSe3. Linear antiferromagnetism in Ba2MnX3 (X = S,Se)Hugo Steinfink and I. E. GreyCite this: Inorg. Chem. 1971, 10, 4, 691–696Publication Date (Print):April 1, 1971Publication History Published online1 May 2002Published inissue 1 April 1971https://do…
The omega phase in as-quenched and aged Ti-V alloys was examined using high-resolution dark-field microscopy and selected-area diffraction. The asquenched omega morphology was shown to be based upon 〈111〉β‖〈0001〉ω rows containing particles which are 10-22 Å in diameter with an interparticle spacing of 20-25 Å. Cluster…