Materials Literature
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Abstract The behaviour of single crystal specimens of MgZn 2 deformed by basal slip is investigated by both dynamic and creep tests at temperatures between 250 and 500 °C. With the dynamic experiments a smooth upper yield point is observed. The temperature dependence of the critical resolved shear stress and of the se…
Activation of rare‐earth oxides by ions other than rare earths is successfully attempted in the present investigation. Bi +3 is incorporated in yttrium, gadolinium, and lanthanum oxides by solid state reaction. Probably a chargetransfer mechanism involving bismuth and oxygen introduces an absorption band at about 3200…
The decomposition into nitrogen and hydrogen on heated filaments was studied at pressures of 10–4 torr and less with both conventional and ultra-high vacuum (u.h.v.) techniques. The reaction probability P of an ammonia molecule at a collision with the platinum was determined under various conditions. Particular attent…
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Defects in single crystals of solution-grown surcrose have been studied using optical and electron microscopy. From an examination of the etch figures (produced by aqueous ethanol) and the cleavage patterns on {100} faces it is shown that dislocations may move on the {h10} planes in the 〈001〉 directions and on the {h0…
In the tail part region of the first exciton band, the absorption constant (10 -1 to 10 2 cm -1 ) was measured on zone-refined and Harshaw NaCl single crystals from 10°K to 573°K. Fundamental absorption tails of pure NaCl single crystals are represented by the modified Urbach rule, which describes the influence of zer…
Abstract Dilatométric studies on five PMM samples of different tacticities show generally three transition ranges between −35 and 150°C. The main glass transition temperature depends on the relative proportion of the iso‐ or syndiotactic segments. The secondary transition, located around 60°C., seems to be related to…
Abstract A 12×12 representation is given of the valence band Hamiltonian at k = 0 which includes the spin‐orbit interaction. Expressions are derived for the energies and the linear combinations of the wave functions for the Γ 7 , Γ 8 , and Γ 9 subbands. The whole valence band is completely determined by eight paramete…
The addition of tributyltin methoxide and of biotributyltin oxide to the following acceptor molecules is described : isothiocyanates, trichloroacetonitrile, carbon disulphide, carbon dioxide, sulphur dioxide, and carbodi-imides. The corresponding phenoxide is generally less reactive than the methoxide. The initial pro…
The oligomerization of substituted phenyl glycidyl ethers was studied kinetically in the presence of dimethylbenzylamine using toluene or dioxane as a solvent. The infrared spectra of the resultant oligomers suggest that the reaction products have the internal carbon-carbon double-bond un-saturation, which is confirme…
The addition of halide ions causes an increase in the observed bimolecular rate constant k0 for the Fe(II)+H2O2 reaction, ultimately reaching a limiting value depending on the anion. This is interpreted in terms of complex formation between ferrous ions and halide ions, with the complex reacting faster than the hexa-a…
Abstract Density, morphology, and melting data on linear polyethylene and high molecular weight polymethylene crystallized from the melt under elevated pressure are presented. For approximately constant supercooling a sharp density increase is noted above 2300 atm. crystallization pressure. Above 4000 atm. densities a…
Activation of rare earth vanadate by ions other than rare earths is successfully attempted in the present investigation. Bi +3 can be incorporated in the and lattice by solid‐state reaction. The phosphor , excited by cathode rays or uv radiation, shows luminescence with a continuous emission band extending from 4000 t…
New data have been used in a refinement which leads to molecular dimensions P-O (bridge) 1.612+ 0.005 A, P-O (outer) 1.
Abstract By using the method of free torsion vibrations, a detailed dependence was determined of the temperature position and the height of the secondary (β) loss maximum of alkali‐polymerized polycaprolactam upon the concentration of water in the range of 0 < P A < 1.3, where P A is the number of moles of water…
Manganese‐activated phosphors were prepared by solid state reactions throughout the spinel crystalline solution region in the system. The best ultraviolet‐excited phosphor examined, , is characterized by a peak emission wavelength at 512 ran, a 50% peak intensity band width of 36 nm, and a quantum efficiency equivalen…
By using a high‐speed technique described in ref. (1), anodic (aluminum dissolution) polarization data have been obtained for aluminum surfaces free from oxide films and from the normal concurrent hydrogen evolution. Similarly cathodic (hydrogen evolution) polarization data have been produced for oxide‐free aluminum s…
Vibrational spectra of the following ions are reported: InCl63–, TlCl63–, PbCl64–, SbCl63–, BiCl63–, SeCl62–, TeCl62–, SbCl52–. It is suggested that ν3 for the octahedral “inert pair ions” may be anomalously broad. In species such as Cs2SbCl6 the presence of SbIII and SbV is observed and the relative intensities of th…
Abstract Polyethylene networks were prepared by γ‐irradiation of linear polyethylene, both molten and crystalline. The elastic and photoelastic properties of the networks were studied at high temperatures, i.e., in the molten state. The equilibrium swelling was also measured in several solvents. Values of the crosslin…
The cathodoluminescence from Eu 3+ and Tb 3+ in the orthoborates of In, Sc, Y, La, Gd, and Lu is examined. The host is shown to be particularly effective for both activators. Observed spectral details of the luminescence are related to effects of crystal symmetry on electronic transitions.