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61.
Transient magnetic fields were measured for W, Os and Pt ions traversing iron hosts with average velocities in the range from approximately 1.6v 0 to 4.8v 0 (v 0=c/137, Bohr velocity). Transient fields for W and Os in Fe are consistent with behaviour found for lighter rare-earth ions and are about 20% stronger than those for Pt in Fe over the majority of the velocity range examined. A measurement was made to confirm that possible heavy-ion beam induced attenuations of the transient field are negligible for low-velocity Pt ions excited by Ni beams. Results are discussed in terms of both empirical and model-based parameterizations of the transient field strength.  相似文献   
62.
63.
We consider the motion of a particle in a plane under the gravitational action of 3 fixed centers (the 3-center planar problem). As it is well known (Vestnik Moskov. Univ. Ser. 1 Matem. Mekh 6 (1984) 65; Prikl. Matem. i Mekhan. 48 (1984) 356; Classical Planar Scattering by Coulombic Potentials, Lecture Notes in Physics, Springer, Berlin, 1992) on the non-negative level sets of the energy E there do not exist non-constant analytic first integrals, and moreover the system has chaotic trajectories. These results were proved by variational methods.Here we investigate the problem in the domain of small negative values of E. Moreover, we assume that one of the centers is far away from the other two. Then we get a two-parameter singular perturbation of an integrable dynamical system: the 2-center problem on the zero-energy level. The main problem we deal with is to prove that the Poincaré-Melnikov theory applies in the limit case E→0.  相似文献   
64.
65.
Translated from Matematicheskie Zametki, Vol. 51, No. 2, pp. 20–28, February, 1992.  相似文献   
66.
Representatives of a new class of mesogenic compounds have been synthesized, -(5-substituted-2-pyridyl)-4-alkylacetophenones, which have an intramolecular hydrogen bond. The mesogenic properties of these compounds have been investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 486–488, April, 1993.  相似文献   
67.
We consider Lagrangian systems in the presence of nondegenerate gyroscopic forces. The problem of stability of a degenerate equilibrium pointO and the existence of asymptotic solutions is studied. In particular we show that nondegenerate gyroscopic forces in general have, at least formally, a stabilizing effect whenO is a strict maximum point of the potential energy. It turns out that when we switch on arbitrary small nondegenerate gyroscopic forces, a bifurcation phenomenon arises: the instability properties ofO are transferred to a compact invariant set which collapses atO when the gyroscopic forces are switched off.Work supported by Russian Fund of Basic Research, the Italian Research Council (CNR) and the Italian Ministery of University (MURST)  相似文献   
68.
The gyromagnetic ratios of levels up to the 10 1 + in the ground-state band and of the 2 2 + state in theγ-band of166Er were simultaneously determined experimentally by means of the thin-foil, perturbedγ-ray angular distribution technique utilizing the transient hyperfine field manifest at nuclei of Er ions rapidly traversing polarized Fe. Beams of 220- and 160-MeV58Ni projectiles were used to Coulomb excite the levels of interest. The present results are compared with the spin-dependencies ofg-factors of levels in the ground-band predicted by recent cranked Hartree-Fock-Bogoliubov calculations and with interacting boson model expectations which includeg-boson effects.  相似文献   
69.
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In view of the dramatic difference in the spectral-luminescence properties of α-(p-chlorobenzoyl)-4-diethylaminocinnamonitrile and α-ethoxycarbonyl-4-diethylaminocinnamonitrile in solutions and in the crystalline state, X-ray diffraction analysis has been applied to study crystals of these compounds. The intermolecular C-H...N and C-H...O hydrogen bonds are found to contribute to the quinoidization of molecules, which leads to a bathochromic shift in the absorption and fluorescence spectra. A spectral-luminescence study of the aforementioned compounds has revealed that the solvent temperature and polarity affect the position of absorption and luminescence peaks: a decrease in these parameters causes a hypsochromic shift.  相似文献   
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