Materials Literature
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Fine single‐domain and polydomain particles of tetragonal ZrO 2 were prepared by hydrothermal and heat treatment of ZrO 2 · n H 2 O. The particles were characterized by X‐ray diffraction, electron microscopy, NMR, mass spectrometry, and ir spectroscopy. The main impurity in the samples was 1 to 2 wt% OH − ions, most o…
A simple theoretical calculation is given in which the energy distribution of low-energy secondary electrons emitted from metals is derived. The main feature of the calculation is an energy-dependent electron mean free path. The theory predicts that the peak of the energy distribution occurs at a value of the secondar…
RELATIVE EFFICIENCY OF CARBONATE DISSOLUTION AND PRECIPITATION DURING DIAGENESIS: A PROGRESS REPORT ON THE ROLE OF SOLUTION CHEMISTRY
The mechanical behavior of uranium and its alloys is reviewed with special emphasis on plastic flow behavior of polycrystalline materials. The strength of uranium is influenced by crystal structure as well as by point, planar, and volume defects; wit these factors in mind, texture hardening, strain hardening, solute h…
A neutron diffraction study has been made on the magnetic structure of single crystalline Mn 3 O 4 from liquid helium temperature to the Neel point, 41K, and the nuclear structure at room temperature has been refined.
Films of rubidium were deposited on quartz substrates by evaporation at pressures of less than 10−10 Torr. The work function of the films was determined photoelectrically, and at 140 K was found to be (2.261 ± 0.015) eV. Warming the film to room temperature caused an irreversible reduction of about an order of magnitu…
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.