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991.
Helmut Duddeck M. H. A. Elgamal Guiliana Severini Ricca Bruno Danieli Giovanni Palmisano 《Magnetic resonance in chemistry : MRC》1978,11(3):130-132
The 13C NMR data of six pairs of 18α/18β-glycyrrhetic acid derivatives are presented. It is shown that the configuration at C-18 can easily be recognized by inspecting the chemical shifts of several characteristic carbons, e.g. C-12, C-13, C-18 and C-28. The shifts of these carbons originated by the change of the D/E ring junction proved to be largely independent of the substitution at C-3 and C-20. 相似文献
992.
993.
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
994.
995.
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
996.
997.
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
998.
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
999.
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
1000.
Helmut Oeljeklaus 《Mathematische Annalen》1973,206(3):225-236
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