Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Thermally and IR-stimulated luminescence and conductivity of Cu and Li doped ZnO single crystals have been investigated in the temperature range from 5 to 100 K. It is shown that the stimulation of the green emission is related to the generation of free charge carriers, while the yellow emission is produced mainly by…
The orientation factor, K, of elastic dislocation energy is calculated for dislocations in KDP (space group I42d) with Burgers vectors b = 〈100〉, [001], 〈110〉, 〈011〉, and 1/2〈111〉. As a result of elastic anisotropy, for dislocations with b = 〈110〉, K has an absolute maximum in pure screw orientation. The preferred lin…
The photoelectronic properties of virgin CdS platelets, sublimed and cooled in an N2–H2S atmosphere, were altered by heat treatment in ultra-high vacuum. The untreated crystals showed a strongly structured spectral distribution of the photoconductivity (SDP) at liquid nitrogen temperature (LNT), having maxima (Class I…
The initial stages of ordering in Ni3Mo and Ni4Mo have been investigated by transmission electron microscopy and diffraction. The development of long-range order in Ni3Mo is associated with decomposition into the two metastable phases Ni2Mo and Ni4Mo, which are eventually replaced by the equilibrium Ni3Mo at a later s…
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…