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991.
I. P. Belomestnykh N. N. Rozhdestvenskaya G. V. Isagulyants 《Chemistry of Heterocyclic Compounds》1994,30(6):701-708
The dehydrogenation of a series of alkylpyrïdines has been studied on vanadium and molybdenum oxide-containing catalysts in the presence of oxygen of the air and sulfur dioxide gas. A dependence was shown of the catalytic and physicochemical properties of the catalysts indicated on their composition and method of preparation. The optimum catalyst composition and the conditions of carrying out the reaction to provide high activity and selectivity when making vinylpyridines were determined. The relative reactivity of the alkylpyridines investigated on dehydrogenation and further oxidation was determined.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 802–811, June, 1994. Original article submitted April 19, 1994. 相似文献
992.
M. I. Dykman D. G. Luchinsky R. Mannella P. V. E. McClintock N. D. Stein N. G. Stocks 《Il Nuovo Cimento D》1995,17(7-8):661-683
Summary We outline the historical development of stochastic resonance (SR), a phenomenon in which the signal and/or the signal-to-noise
ratio in a nonlinear system increase with increasing intensity of noise. We discuss basic theoretical ideas explaining and
describing SR, and we review some revealing experimental data that place SR within the wider context of statistical physics.
We emphasize the close relationship of SR to some effects that are well known in condensed-matter physics.
Paper presented at the International Workshop ?Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing
and Related Phenomena?, Elba, 5–10 June 1994. 相似文献
993.
The capability of double focussing magnetic sector inductively coupled plasma mass spectrometry (HR-ICP-MS) for the determination
of trace elements in different body fluids was investigated in commercially available control materials. The elements included
in this study were: Al, As, Cd, Cr, Co, Cu, Hg, Mn, Ni, Pb, Sb, Se, Tl and Zn. Sample preparation, instrument stability and
the results, which are in very good agreement to the given values, are presented and discussed.
Received: 27 August 1997 / Revised: 19 November 1997 / Accepted: 23 November 1997 相似文献
994.
A. V. Shapovalov I. V. Shirokov Ya. V. Lisitsyn V. I. Firstov 《Russian Physics Journal》1995,38(2):209-212
D'alambert's equation is used as an example to study the possibilities of a new method of exactly integrating systems of linear differential equations — the method of noncommutative integration (NI). The results confirm that use of the NI is equivalent to complete separation of the variables in the case of four-dimensional subalgebras of conformal algebra. However, the method does simplify determination of the exact solution in this instance.Tomsk University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 120–124, February, 1995. 相似文献
995.
B. Vizoso I. R. Matías M. López-Amo M. A. Muriel J. M. López-Higuera 《Optical and Quantum Electronics》1995,27(10):847-857
The design of a double-parallel amplified recirculating optical delay line utilizing an erbium-doped fibre amplifier for a fibre optical bus is described. This structure is used for amplifying, equalizing and filtering multicarrier signals coming from optoelectronic units attached to fibre couplers. The use of this structure for a hybrid multimode-singlemode fibre bus that includes optoelectronic units for sensors is also demonstrated. 相似文献
996.
We calculate aPT-odd one-loop meson radiative correction to the scattering amplitude of a nucleon on the external field of the nucleus. The nonrelativistic limit of this amplitude, Fourier transformed to the configuration space, can be interpreted as a single particlePT-odd potential for a valence nucleon. Bound state effects on this potential are evaluated and found to be negligible. 相似文献
997.
The Lie symmetries of nonlinear diffusion equations with convection term are completely described. The Lie ansatzes and exact solutions of a certain nonlinear generalization of the Murray equation are constructed. An example of the family of non-Lie solutions of the Murray equation is given. 相似文献
998.
999.
A. B. Drovosekov N. M. Kreines D. I. Kholin V. F. Meshcheryakov M. A. Milyaev L. N. Romashev V. V. Ustinov 《JETP Letters》1998,67(9):727-732
The excitation spectrum in an [Fe/Cr]n multilayer structure with non-collinear magnetic ordering was studied by the ferromagnetic resonance (FMR) method in the
frequency interval 9.5–37 GHz at room temperature. Besides an acoustic branch, several additional modes were observed under
parallel excitation of resonance. The FMR spectrum was calculated analytically in a biquadratic exchange model, neglecting
in-plane anisotropy, for an infinite number of layers in the structure and numerically for a finite number of layers contained
in real samples. It was shown that the observed modes correspond to excitation of standing spin waves with wave vectors perpendicular
to the film plane.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 9, 690–695 (10 May 1998) 相似文献
1000.
D. A. Ténné V. A. Gaisler N. T. Moshegov A. I. Toropov A. P. Shebanin 《JETP Letters》1998,68(1):53-58
Experiments on Raman scattering in the “forward” geometry, permitting observation of anisotropy of the optical phonons, are
performed on specially prepared short-period GaAs/AlAs superlattice structures with the substrates removed and the surfaces
covered with an antireflective layer. The experimental data agree well with the computational results obtained for the angular
dispersion of optical phonons in superlattices on the basis of a modified continuum model.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 1, 50–55 (10 July 1998) 相似文献