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991.
Brillouin scattering is observed in the InxGa1?xP solid solution with 0.38 ? × ? 0. The composition dependences of the longitudinal and transverse acoustic phonons propagating along the [111] direction are investigated and compared with the expressions derived by Lakshmi et al. from the random element isodisplacement theory. Pronounced broadening of the Brillouin peaks is observed with the increasing amount of In in GaP. 相似文献
992.
Measurements of the reorientation of O-2 centres in RbI and RbBr at low temperatures together with earlier measurements in different alkali halides suggest the following sequence of relaxation mechanisms in an unstressed srystal: Below about 3°K a one phonon tunneling process, then an activated tunneling process through the first librational state, and above 10°K a classical jumping process over the potential well. 相似文献
993.
994.
Hannu Väliaho 《BIT Numerical Mathematics》1979,19(2):256-269
A procedure is proposed for the parametric linear programming problem where all the coefficients are linear or polynomial functions of a scalar parameter. The solution vector and the optimum value are determined explicitly as rational functions of the parameter. In addition to standard linear programming technique, only the determination of eigenvalues is required. The procedure is compared to those by Dinkelbach and Zsigmond, and a numerical example is given. 相似文献
995.
The self-consistent modification of an inhomogeneous plasma density profile near the critical layer due to the ponderomotive force of an obliquely incident p-polarized electromagnetic wave is calculated within a simple hydrodynamic plasma model. 相似文献
996.
R. Lutter O. Häusser D.J. Donahue R.L. Hershberger F. Riess H. Bohn T. Faestermann F.v. Feilitzsch K.E.G. Löbner 《Nuclear Physics A》1974,229(2):230-240
The g-factor of the 480 ns, 9? isomer at 2.237 MeV in 200Pb was measured by the time-differential perturbed angular distribution method. The result, g = ?0.0285±0.0011 confirms the rather pure quasiparticle structure of this state. Half-lives of 480±20 ns, 43±3 ns and 42±4 ns have been measured for the 2237 keV 9?, 2154 keV 7? states in 200Pb and the 2208 keV state in 202Pb, respectively; E2 transitions and g-factors of negative-parity states in even, neutron-deficient Pb isotopes are discussed. 相似文献
997.
R. Pässler 《Czechoslovak Journal of Physics》1974,24(3):322-339
Nonradiative multiphonon transitions generated by the interaction of the electronic system with quantized normal oscillation modes are described quantum-theoretically on the basis of the static coupling scheme which is an essential, physically plausible alternative model to the adiabatic coupling scheme predominantly used in earlier papers. Putting emphasis on the mathematical correctness of the calculations we obtain a generally valid expression for nonradiative multiphonon transition rates which is based on the concept of temperature-averaged overlap factors. In the case of a single phonon energy this result is reduced to very compact expressions not given in original papers published so far. For non-vanishing phonon dispersion a simple standard formula is given which is suited for approximative numerical calculations. 相似文献
998.
The polarization of neutrons produced in the reaction12C(d, n 0)13N was measured. Deuterons from the Karlsruhe isochronous cyclotron were used to induce this reaction at 51,5 MeV laboratory energy. The degree of polarization was determined by using the special features of Mott-Schwinger scattering. With an uranium scatterer analysing efficiencies of up to 0.92 can be obtained at very small angles (0.23°). The analysing efficiency can be calculated if the differential cross section at 0° and the total cross section is known. These quantities were experimentally determined. The differential cross section for 49.4 MeV neutrons, scattered by uranium, was measured between 0.88° and 2.10°. By an extrapolation the value 43.4±2.6 b/sr was found for the nuclear differential cross section at zero degree. A total cross section ofσ t=4.80±0.22 b was obtained. The neutron polarization was measured at a reaction angle of 24.5° and the result isP=?0.45±0.07. This value is fairly above the semiclassical 1/3 limit and can be only explained, if spin orbit forces are taken into account. For (d, n) reactions this is the first neutron-polarization measurement above an energy of 20 MeV. 相似文献
999.
Helmut Mäurer 《Geometriae Dedicata》1973,2(2):261-268
Ohne Zusammenfassung 相似文献
1000.
The reaction between indole and N-(2-haloacyl)pyridinium salts has been studied. With dioxan as solvent 1-(2-haloacyl)indole (2) was generally the product at low temperatures and 3-(2-haloacyl)indole (1) at high temperatures, as illustrated by the following α-bromopropionylation: Product ratio (1c/2a), 20° (0·01), 40° (0·8) and 60° (8·5). The fact that the a-bromobutyrylation at 60° gave 3-{N-(2-bromobutyryl)-1,4-dihydro-4-pyridyl}indole (6) as the main product, and 3-(2-bromobutyryl)indole (1d) only as a minor product, shows that the 3-acylation is affected by steric hindrance.At high reaction temperature (> 60°) the yield of1 decreased, owing to the formation of 3-indacylpyridinium salts (4). 相似文献