Materials Literature
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I. Introduction 332 II. Excitation of Electrons Due to the Internal Energy of the Atomic Particle-plus-solid System and Potential Ejection of Electrons 332 III. Kinetic Ejection of Electrons in Vacuum 342 IV. Radiative (Induced) Conductivity of Semiconductors Bombarded with Ions 353 V. Excitation of Luminescence by Io…
CONTENTS I. Introduction 156 II. Complex halides in vapour form 156 III. Increase in the thermal stability of complex halides on vaporisation 159 IV. Connection between complex formation and dimerisation of compounds in the vapour state 161
Abstract Silica fibres and flame polished rods having strengths around 600 Kg/mm2 were prepared and the preparation conditions studied. The effects on fibre strengths of atmospheric and temperature changes, and of variations in rate of stressing and previous heat treatment, were extensively investigated. From the resu…
The temperature-modulated reflectance, $\frac{\ensuremath{\Delta}R}{R}$, of gold films has been measured from 2 to 10 eV. The range of modulated reflectance experiments is thus extended into the vacuum ultraviolet. The observed structure, which is much more complex than the conventional reflectance spectra, is of cons…
The infrared spectra of 9,10-anthraquinone and 9,10-anthraquinone-d8 of high isotopic purity have been measured in the 4000–33 cm−1 region both in solution and in the solid. Polarized spectra have been taken on thin layers of oriented crystals grown between KBr plates. Group-theoretical analyses were made for the free…
Lattice response functions, such as the thermal conductivity and dielectric susceptibility of an imperfect crystal with rocksalt structure, are evaluated in terms of the irreducible $T$ matrix accounting for the phonon scattering. It is shown that the effect of defects on thermal conductivity and dielectric susceptibi…
A study of electrostriction in strontium titanate provides evidence that SrTi${\mathrm{O}}_{3}$ is not perfectly cubic. It exhibits a small but noticeable piezoelectric effect whose temperature and field dependence is $\frac{E}{(T\ensuremath{-}{T}_{a})}$, whereas the electrostrictive effect was found to vary as $\frac…
For equivalent values of plastic strain, the dislocation density and point-defect concentration following deformation by the propagation of high-amplitude shock waves (70 to 330 kbar) through high-purity polycrystalline nickel are appreciably larger than as a result of cold rolling near 0°C. Based on the electrical-re…
Evidence is presented for the existence of two overlapping dispersions at 20°C in toluene. Resolution of the two dispersions was in terms of separate Debye relaxation processes, with dispersion parameters ε01=2.384, ε∞1=2.269, and τ1=5.80×10−12 sec for the low-frequency process and ε02=2.269, ε∞2=2.222, and τ2=2.0×10−…
An analysis of the experimental evidence in Part I of this paper clearly indicates that for the case of copper crystals, striations in low-amplitude fatigue are suppressed by strong slip on intersecting slip planes, including the cross slip system, but are formed by interactions between dislocations on the primary gli…
The lattice parameter of La 2 Ce 2 O 7 fired at 1 400 °C was found to be 5.5700 ± 7 Å (at 20 ± 2 °C). Its crystal structure was of the disordered fluorite rather than the pyrochlore type. The degree of order in the structure could not be established from the neutron powder diffraction pattern, but it is likely that th…
Reactions between cation vacancies and Cr3+ impurity ions in single crystals of magnesium oxide are studied using optical techniques to determine the concentrations of the reaction components. Several new features of the Cr3+-ion luminescence spectrum are reported. The spectrum of these impurity ions is very sensitive…
New experimental data on the ultraviolet optical properties of single-crystal magnesium oxide are presented in the range 4.0-14.5 eV. Normal-incidence reflectance data exhibit three strong peaks at 7.60, 11.05, and 13.50 eV. The first peak, due to an excition transition at $\ensuremath{\Gamma}$, shows strong temperatu…
The thermal-expansion and room-temperature lattice constants were determined for several phosphates and arsenates isomorphous to KH2PO4. From these data, the lattice constants were calculated at the ferroelectric antiferroelectric temperature. They show a nearly identical c/a ratio for the compounds of any given alkal…
Thermogravimetric (t.g.a.) and differential thermal analyses (d.t.a.) of ϵ-Zn(OH) 2 , Zn 5 (OH) 8 Cl 2 .H 2 O, β-ZnOHCl, and ZnOHF are reported and discussed. The results show that the replacement of a hydroxyl group by a halogen group contributes to greater thermal stability of the hydroxy compound. The thermal stabi…
The elastic constants of single crystals of magnesium and of dilute alloys of magnesium with lithium have been measured at 298\ifmmode^\circ\else\textdegree\fi{}K using the pulse-echo technique. The alloys covered the range of 1.841-2.0 electrons per atom. All fundamental elastic constants decrease with increasing lit…
Impact shear tests of the Kolsky thin-wafer type were used to determine the effect of temperature and strain rate on the critical resolved shear stress for slip in aluminum single crystals at strain rates of 104 sec−1 and in the temperature range 20° to 500°K. The aluminum deformed in a viscous manner in that the flow…
Diamagnetic α-ZnMoO4, the stable phase at STP, is triclinic with lattice constants a=9.625±0.015 Å, b=6.965±0.010 Å, c=8.373±0.015 Å, α=103.28°±0.15°, β=96.30°±0.15°, and γ=106.72±0.15° at 298°K, with six formula weights in the unit cell. The integrated intensities of 6489 reflections in a reciprocal hemisphere with (…
A simple formula in closed form is proposed for the thermal accomodation coefficient from which the accommodation coefficient of a monatomic gas—solid system may be calculated from certain basic parameters of the system. The formula α(T)=1−exp(−T0/T)+α(∞) tanh{[(MT)1/2/α(∞)](a/λ)} exp(−T0/T)is obtained from considerat…
This paper reports measurements of the shift with hydrostatic pressure and uniaxial stress of the temperature for a metal-to-semiconductor transition in ${\mathrm{V}}_{2}$${\mathrm{O}}_{3}$; of the change with pressure and uniaxial stress of the resistivity in the metallic phase and the activation energy for condution…