Materials Literature
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Segregation from solutions and melts is compared theoretically. It is shown from thermodynamic arguments that equilibrium solution segregation is more effective. Segregation coefficients k0 are calculated for aqueous alkali halide systems, based upon theoretical heat of dissolution values (solid solution) and solubili…
dc Electric-field induced optical second-harmonic generation has been measured for CH4, CH3F, CH2F2, CHF3, CF4, CClF3, and CBrF3. For CH4 and CF4 the third order hyperpolarizability χ(−2ω; 0,ω,ω) is obtained directly. For the other (dipolar) molecules, a bond additivity estimate for χ(−2ω; 0,ω,ω) is used to extract th…
Raman scattering of single crystals of ${({\mathrm{Ti}}_{1\ensuremath{-}x}{\mathrm{V}}_{x})}_{2}{\mathrm{O}}_{3}$ with $0\ensuremath{\le}x\ensuremath{\le}0.3$ has been measured between 80 and 700 \ifmmode^\circ\else\textdegree\fi{}K. All seven Raman-active phonons of the ${D}_{3d}^{6}$ space-group symmetry were found…
The relation between shifts in Auger energies and shifts in electron binding energies is explored. The prediction of Auger energies in metals from one-hole and two-hole optical energies as well as from electron binding energies in metals is described, with proper accounting for final-state coupling, relaxation, and re…
Insulator samples of Plexiglas and alumina ceramic in vacuum have been subjected to high-voltage pulses with rise times of a few nanoseconds. Breakdown paths were inclined to the electric field in the presence of a magnetic field normal to the insulator surface, analogous to the Hall effect for bulk conduction. These…
The electronic-energy-band structure of the layered dichalcogenides Ti${\mathrm{S}}_{2}$ and Ti${\mathrm{Se}}_{2}$ has been determined using the Korringa-Kohn-Rostoker (KKR) method. Crystal potentials were constructed from overlapping atomic charge densities in the muffin-tin approximation for both full Slater exchang…
We report the dielectric constants of $p$, ${p}^{\ensuremath{'}}$-di-$n$-heptyl azoxybenzene in the nematic and in the smectic-$A$ phase. Around the nematic-smectic transition ${\ensuremath{\epsilon}}_{\ensuremath{\parallel}}$ decreases with decreasing temperature while ${\ensuremath{\epsilon}}_{\ensuremath{\perp}}$ i…
We have measured the detailed temperature dependence of the cholesteric pitch in cholesteryl nonanoate near the smectic-$A$ transition. The data show a power-law behavior with an exponent $\ensuremath{\nu}=0.675\ifmmode\pm\else\textpm\fi{}0.025$, in agreement with theoretical prediction and with elastic-constant measu…
Diffusion couples, consisting of sapphire and fused silica, which were annealed in the temperature range from 1678 degrees to 2003 degrees C and analyzed by electron beam microprobe, have provided data on the stable phase equilibrium of the silica-alumina system. Under stable equilibrium conditions, the intermediate c…
A twisted nematic liquid crystal is shown by theory and experiment to rotate incident plane-polarised light by π/2 only at specified wavelengths. At other wavelengths, elliptically polarised light is produced. This action determines the contrast ratio of some twisted nematic devices.
We report heat-capacity, x-ray, electrical-conductivity, and Seebeck-coefficient measurements in the range $200<T<900$ K, which indicate that there exist two high-temperature, band-type phases in ${({\mathrm{Cr}}_{0.01}\phantom{\rule{0ex}{0ex}}{\mathrm{V}}_{0.99})}_{2}$${\mathrm{O}}_{3}$. The electrical anomaly…
The temperature dependence is measured from 4 to 40 K of the frequency of tunnelling rotation of methyl groups in free radicals in gamma -irradiated methyl malonic acid crystals. Above 25 K the frequency, while remaining well defined, declines sharply with increasing temperature.
For pt.I, see ibid., vol.7, 76 (1974). Small (18-32 atoms) periodic clusters of two-dimensional hexagonal graphite and boron nitride are shown to represent some high-symmetry points in the Brillouin zone of the infinite crystal. Semi-empirical all-valence electron calculations are performed on these clusters and the b…
Using a light-beating spectrometer, we have observed in the smectic-$A$ phase of $p$-cyanobenzilidene-$p$-octyloxyaniline the thermally excited undulations of layers predicted by de Gennes. From the wave-vector dependence of their damping time we determined the diffusivity of the angular orientation, $\frac{{K}_{1}}{\…
A LEED pattern given by a thin film of gold deposited on the (111) surface of a silicon crystal shows an unusual combination of spots and lines. It is suggested that the structure is essentially two-dimensional, with lattice points regularly spaced along certain lines, but with adjacent lines randomly either in phase…
The structure of solid solutions of ZrO 2 containing 18%, 22% and 26% YO 1.5 as well as 26% YbO 1.5 have been examined by Bragg neutron diffraction and the diffuse scattering of long wavelength (7 AA) neutrons. The evidence points to a relaxation (0.36 AA) of the six nearest-neighbour oxygen ions surrounding an anion…
The most complex types of nitrogen compound in beer (here termed “proteoses”) are, when not combined with polyphenols, highly surface active and hence concentrate in the foam. With unhopped beer, the foam is of the “liquid-viscous” type, which eventually drains and collapses leaving no residual solids. The iso-α-acids…
Phase relations in the system ZrSiO4-TiO2 was investigated by a quenching method. Mixtures of ZrSiO4 and TiO2 were heated from 1500° to 1700°C in air with silicon carbide heating element furnace. Phases in the quenched specimens were identified by a X-ray diffraction method and also under a reflecting microscope. TiO2…
The defective spinel in the system RO⋅Al2O3-Al2O3 at the lower temperature below about 1100°C, was synthesized, and it was named as γ-spinel and its meta-stable region was explanatorily draw by G. Yamaguchi in 1953.In the present investigation, this phase boundary has been revealed experimentally by the X-ray diffract…
W ith the aim of p roducing a reducing gas of(CO. + H .O):O;;7o o and the soot cOlltent less thall 5 g/Nm 3 at a low cost by reforming gaseous hydrocarbon with C O 2 and H 2 0 contained ill the blast furnace tOll gas, the effects of the retentioll time, the reaction temperature and catalysts were checked by carrying o…