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An expression is obtained for the lattice thermal conductivity of an anharmonic crystal by the method of double-time Green's functions using the energy-flux operator propounded by Hardy. The study uses cubic and quartic anharmonic terms in the crystal Hamiltonian. It is found that the nondiagonal part of the energy-fl…
The purpose of this paper is to present a quantum-mechanical theory of the inelastic scattering of slow electrons by long-wavelength surface optical phonons for simple models of an ionic crystal and for a nonionic crystal such as silicon. It is argued that a quantum-mechanical approach is necessary for this problem. H…
The quantization of the motion, perpendicular to the surface, of electrons in an inversion layer at the surface of a silicon substrate is experimentally verified by accurate capacitance measurements at 77 and 300 \ifmmode^\circ\else\textdegree\fi{}K. From the measurements the average distance of the electrons from the…
Raman scattering from the mixed crystal K${\mathrm{Ta}}_{0.64}$${\mathrm{Nb}}_{0.36}$${\mathrm{O}}_{3}$ (${T}_{c}\ensuremath{\approx}10$\ifmmode^\circ\else\textdegree\fi{}C) has been investigated as a function of temperature in the paraelectric and single-domain-ferroelectric phases. The phonon spectrum was found to c…
By Monte Carlo calculations in the canonical ensemble, we have studied some properties of a two-dimensional system of 170 long hard ellipses (whose axis ratio equals 6). This system can be considered as a two-dimensional model for a nematic liquid crystal. We have shown that this system exhibits two first-order phase…
The toroidal but parallel array of planes of unidirectionally oriented molecules believed to characterize cholesteric liquid crystals also gives rise to certain geometrical patterns. The reality of this structure is demonstrated by micrographic evidence.
The review presents a detailed summary of the current understanding of the phenomenon of corrosion fatigue in gaseous and in aqueous environments. The effects of gaseous environments at low and at elevated temperatures and the mechanisms which govern fatigue crack initiation and propagation in the presence and in the…
Abstract Phosphatschichten wurden erhalten durch anodisches Phosphatieren in Natriumphosphatlösungen (2,5 bis 5% Phosphat, PH 4,2 bis 5,4 Stromdichte 2,5 bis 5,0 mA/cm 2 ). Die Phosphatschichten (Schischtgemisch 7,3 bis 20 g/m 2 ) bestehen aus Ferri‐Ferro‐Phosphat, wobei das Verhältnis Fe 2+ :Fe 3+ von der Badzusammen…
The polarized Raman spectra of the room temperature (ordered) phase and the high temperature (disordered) phase of cesium nitrate have been recorded. The assignment of the spectral bands differs somewhat from earlier reports of the room temperature phase with a to/lo splitting of the ν3(E) band at ∼ 1350–1400 cm−1 rep…
Abstract Aus CdCl 2 oder CdBr 2 ließ sich durch Umsetzung mit LiBH 4 in Äther kein reines Cd(BH 4 ) 2 gewinnen, wohl aber Li 2 Cd(BH 4 ) 4 als ein Ätheratöl, sowie aus der Umsetzung von CdCl 2 mit NaBH 4 in Äther oder Tetrahydrofuran ein NaCd(BH 4 ) 3 . LiCd(BH 4 ) 3 und NaCd(BH 4 ) 3 bilden sich auch aus den Komponen…
Abstract Both initial network chain densities n M (0) and n s (0) of dicumyl peroxide‐cured natural rubbers were determined from the tensile stress and swelling method, respectively. The difference between n M (0) and n S (0) was usually constant, independent of the magnitude of network chain density. That is, it was…
The effect of swelling porosity on the thermal conductivity of irradiated U 3 Si fuel was deduced from electrical conductivity measurements on samples with pore volume fractions of 0.01 to 0.27. The Maxwell‐Eucken expression adequately represents the data, with β= 1.9±0.1. Postirradiation annealing of samples at 400°…
Abstract Tropone and its various derivatives were found to form several complexes having a composition of 1 : 1, 1 : 2, or 2 : 1 with mercury (II), zinc (II), cadmium (II), copper (II), cobalt (II), manganese (II), and nickel (II). In all cases, co-ordination would occur with the carbonyl oxygen.
Abstract The intermediate products of thermal decomposition of ferrous sulphate heptahydrate, in a current of air, have been investigated by X‐ray and chemical analysis. It was found that the monohydrate undergoes dehydration followed by oxidation, or combined hydrolysis and oxidation to Fe 2 O(SO 4 ) 2 and Fe(OH)SO 4…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure of Anionic Poly(2-phenylbutadiene)R. J. Ambrose and W. L. HergenrotherCite this: Macromolecules 1972, 5, 3, 275–279Publication Date (Print):May 1, 1972Publication History Published online1 May 2002Published inissue 1 May 1972https://pubs.acs.org/doi/10.1021/ma60027…
The electric field at a high voltage electrode is modified by corona discharge in the space surrounding the electrode. A knowledge of the resultant magnitude of the electric field is of value in the theoretical analysis of the corona. Systems of cylindrical geometry are of particular importance because of applications…
Abstract The theory of Raman relaxation is developed without the approximation of small wave vectors for the lattice phonons and it is shown that the accurate theory reduces into the known one if the expressions are expanded into infinite series and only the first term retained. The temperature dependence of electroni…
Thermoluminescent (TL) glow curves of rf-sputtered SiO2 films deposited on silicon have been measured and correlated with optical absorption of the films. As-sputtered SiO2 films are thermoluminescent without further exposure to exciting radiation. Films with a strong optical-absorption band at 7.6 eV (E band) give fi…
On assuming the random distribution of Cr 2+ ions and occupation of intrinsic Cr-vacancy sites, the relation between the equilibrium sulfur pressure P S 2 and the deviation from the stoichiometric composition Cr 2 S 3 was calculated and was confirmed experimentally. The magnetic susceptibility and the electrical resis…
An RTV silicone and high density polyethylene are exposed in an activated gas plasma for varying times and varying conditions. Both oxygen and argon are used. Changes in critical surface tension of wetting as determined by contact angle measurements are reported. Bondability of the treated surfaces is evaluated with b…