Showing papers by "Voronezh State University published in 1996"
01 Jan 1996
TL;DR: In this article, the authors introduce the notion of a stochastic differential equation on a manifold and introduce the chain rules (712) for solutions of Ito and (717) for solution of Stratonovich, respectively, for diffeomorphisms of the separable Hilbert space.
Abstract: In order to introduce the notion of a stochastic differential equation on a manifold we should first recall the chain rules (712) for solutions of Ito stochastic differential equations and (717) for solutions of Stratonovich stochastic differential equations Consider a diffeomorphism of the separable Hilbert space F, namely a change of coordinates Φ: F → F According to (717) a solution of a Stratonovich equation transforms under Φ via the ordinary vector rule (11) while the transformation rule for a solution of an Ito equation is quite different from (11) and corresponds to (712) This means that the Stratonovich equations on a manifold M can be described in terms of sections of the tangent bundle TM, but in order to describe the Ito equations on M we should involve sections of a special bundle (introduced below in this item) whose ‘changes of coordinates’ (Φαβ,gαβ) are generated by (712) That is why the Stratonovich approach is more popular and is used in the literature very often (see, eg, [9, 36, 87], etc) Nevertheless we prefer the Ito approach since it is more convenient for the applications treated in this book, leads to some interesting geometric constructions, and (last but not the least) has many natural inter-relations with some other methods of investigation, eg, with Nelson’s mean derivatives and with the description of the processes in terms of integrals with parallel translation Let us start with the exact definitions
87 citations
TL;DR: In this article, the angular distribution of polarized electrons and the circular dichroism in photoionization of polarized atoms with an arbitrary angular momentum are presented in an invariant vector form.
Abstract: Special reduction formulae for bipolar harmonics with higher ranks of internal spherical functions are derived, which will be useful in problems involving multiple expansions in spherical functions. Together with irreducible tensor operator techniques these results provide a new and effective approach, which enables one to extract the geometrical and dynamical factors from the cross sections of atomic processes with polarized particles with an accurate account of all the polarization effects. The angular distribution of polarized electrons and the circular dichroism in photoionization of polarized atoms with an arbitrary angular momentum are presented in an invariant vector form. A specific circular dichroism, which is caused by the correlation of electron and atom orientations, is discussed. The angular distribution of escaping electrons in double photoionization of unpolarized atom is presented in a simple form. A convenient parametrization is proposed for describing the dependence of the photoprocess cross sections on the polarization state of the photon beam.
59 citations
TL;DR: The key enzymes of the glyoxylate cycle, isocitrate lyase and malate synthase, have been detected in liver of foodstarved rats and found in the peroxisomal cell fraction after organelle fractionation by isopycnic centrifugation.
37 citations
TL;DR: The fractionation ofcarbon isotopes in GDC reaction was revealed which provides essential isotopic effects in plants in addition to the well‐known effect of carbon isotope fractionation by the central photosynthetic enzyme, ribulose‐1,5‐biphosphate carboxylase.
23 citations
TL;DR: In this article, a linear unbounded operator is studied with the aid of a semigroup of difference operators and a difference operator in a sequence space, and the spectrum mapping theorem for the semigroup is obtained.
Abstract: Associated with a family of evolution operators in a complex Banach space is a linear unbounded operator, which is studied with the aid of a semigroup of difference operators and a difference operator in a sequence space. Some formulas for the spectra of the linear operators in question (in particular, for abstract hyperbolic differential operators) and the spectrum mapping theorem for the semigroup of difference operators are obtained.
21 citations
18 citations
TL;DR: The effect of polymer additives on the growth of vapour bubbles in an infinite volume of superheated fluid was analysed in part 1 of the present paper as discussed by the authors and the second part discusses the reasons for the experimentally observed qualitatively different (with respect to a pure solvent) changes in the heat transfer coefficient in bubble boiling of polymer solutions with different macromolecule content.
16 citations
TL;DR: Using the local-density-functional method and spherical jellium model, the electronic structure and static polarizability α(0) of small simple metal clusters surrounding by media with dielectric constants e = 1 ÷ 25 have been calculated.
Abstract: The dipole dynamic polarizability of small sodium and aluminum jelliumlike clusters embedded in different dielectric media has been calculated using the time-dependent density-functional method with the frequency-dependent local exchange-correlation potential. The matrix has been taken into account through a static dielectric constant \ensuremath{\varepsilon}. Photoabsorption resonances obtained within the density-functional theory are redshifted with respect to the position of the classical surface plasmon for a metal sphere of the same size within the same matrix. As \ensuremath{\varepsilon} increases, photoabsorption resonances shift to lower energies. We have discovered that the peaks caused by one-electron transitions and by collective excitations move to lower energies at different rates. For sodium clusters, the surface plasmon shifts more slowly than one-electron resonances; for aluminumlike clusters, the reverse is observed. In the case of sodium, this leads to the displacement of the surface plasmon from the region below the continuum threshold (when the cluster is in vacuum) to the continuum of states (for the cluster embedded in a dielectric). \textcopyright{} 1996 The American Physical Society.
13 citations
TL;DR: In this article, a simple model to describe effect of laser field on structure of molecular vibronic spectra is proposed and the change of the internuclear distance which takes place in experiments on Coulomb explosion is estimated.
12 citations
TL;DR: In this article, the effects of elastic viscosity and diffusion resistance during the growth of vapour bubbles in a superheated polymer solution are investigated based on the approximate solutions of the equations of interphase interaction.
11 citations
TL;DR: In this article, the fracture stability of a macrocrack under tensile and shear loading in the presence of a system of microcracks is analyzed and the influence of crack contact on the stress intensity coefficient is analyzed under the friction free assumption.
TL;DR: In this paper, Tverdogo Tela [Mechanics of solids], No. 5, 170-174 (1984), A. I. Miloslavskii, lzv. Mekh. Akad.
Abstract: 1. S. V. Chelomei, lzv. Akad. Nauk SSSR Ser. Mekh. Tverdogo Tela [Mechanics of Solids], No. 5, 170-174 (1984). 2. V. N. Feodoslev, Inzh. Sb., 10, 169-170 (1951). 3. A. A. Movchan, PriM. Mat. Mekh. [J. Appl. Math. Mekh.], 29, No. 4, 760-762 (1965). 4. P. D. Dotsenko, PriM. Mekh. [Soviet Appl. Mekh.], 15, No. 1, 69-75 (1979). 5. V. I. Z, efirov, V. V. Kolesov, and A. I. Miloslavskii, lzv. Akad. Nauk SSSR Set. Mekh. Tverdogo Tela [Mechanics of Solids], No. 1, 179-187 (1985). 6. A. I. Miloslavskii and Yu. L. Stanislavskii, lzv. Akad. Nauk SSSR Set. Mekh. Tverdogo Tela [Mechanics of Solids], No. 5, 16o-161 (19s6). 7. Bui Ta Long, Application of gunctiona/ Methods to Some Stability Problems [in Russian], Ph. D. Thesis, Moscow State University, Moscow (1968).
TL;DR: In this paper, an analytic expression for the electron Green function of a polar molecule exactly accounting for the dipole moment of the molecular core was obtained in the Born-Oppenheimer approximation.
Abstract: In a one-channel QD approximation, an analytic expression is obtained for the electron Green function of a polar molecule exactly accounting for the dipole moment of the molecular core. This result is valid in the Born - Oppenheimer approximation.
TL;DR: In this article, the motion of an electron in a classical electromagnetic wave, including ponderomotive force effects, is discussed, and an instant-impact approximation is proposed to describe electron impact stimulated reactions under the action of super-strong laser field.
Abstract: We discuss the motion of an electron in a classical electromagnetic wave, including ponderomotive force effects. To describe electron impact stimulated reactions under the action of superstrong laser field we formulate instant-impact approximation. We demonstrate how it can be applied to calculate hard electron-nuclear processes for obtaining the reaction rates for such effects as trident pair production, hard X-ray generation, electrostimulated nuclear fission, and both ions and nuclei excitation by electron impact in the laser field.
TL;DR: In this article, the electronic structure and static polarizability of small simple metal clusters (Al, Li, Na, K, Rb, and Cs) surrounding by media with dielectric constants e = 1 ÷ 25 have been calculated.
Abstract: Using the local-density-functional method and spherical jellium model, the electronic structure and static polarizability α(0) of small simple metal clusters (Al, Li, Na, K, Rb, and Cs) surrounding by media with dielectric constants e = 1 ÷ 25 have been calculated. It has been obtained that α(0) of the smallest clusters with a low mean valence electron density is a decreasing function of e, whereas for the clusters with a high valence electron density it rises with e.
TL;DR: In this paper, the induced discrete conversion involving a nuclear transition in keV-region is considered for the first time and it is shown that the 6.01 h lifetime of the 99 m Tc isomer can be reduced significantly.
TL;DR: In this paper, a simple expression for the dichroism in spontaneous bremsstrahlung and one-photon electron-atom scattering is presented, and the numerical estimation of dichroisms is shown that the effect can be observed experimentally.
01 Jan 1996
TL;DR: In this article, the authors considered stochastic mechanics as the third method of quantization different from the well known Hamiltonian and Lagrangian (based on the path integrals) methods, each of which has its own scope of applicability, they have a large intersection (where the results are equivalent), but none of them includes any other completely.
Abstract: Nelson’s Stochastic Mechanics (see, e.g., [10, 14, 20, 22, 25–27, 71, 72, 92–94, 96, 115, 116, 118–120]) is a mathematical subject based on the ideas of classical physics but giving the same predictions as quantum mechanics. Stochastic mechanics can be considered as the third method of quantization different from the well known Hamiltonian and Lagrangian (based on the path integrals) methods. Each of the methods has its own scope of applicability, they have a large intersection (where the results are equivalent), but none of them includes any other completely.
01 Jan 1996
TL;DR: In this paper, the reader is assumed to be familiar with the basic notions usually used in the probability theory, such as G-algebra, Borei sets, measurable map, measure, independence, and so on.
Abstract: In this book we assume the reader to be familiar with the basic notions usually used in the probability theory, such as G-algebra, Borei sets, measurable map, measure, independence, and so on. In this section, for the sake of convenience of presentation, we give some definitions from the advanced probability theory and the theory of stochastic processes. For the sake of completeness we start with the following.
TL;DR: In this paper, the necessary conditions for nonzero circular dichroism in photon-atom scattering are determined and the polarization dependence of the scattering cross section is analyzed, and the necessary and sufficient conditions for the existence of a nonzero cyclic dichromatic environment are derived.
18 Aug 1996
TL;DR: In this article, an electric voltage arising across a sample of ferroelectric PZT or paraelectric SrTiO/sub 3/ ceramic with perovskite structure under an external bending stress, has been measured over a wide temperature range.
Abstract: An electric voltage, arising across a sample of ferroelectric PZT or paraelectric SrTiO/sub 3/ ceramic with perovskite structure under an external bending stress, has been measured over a wide temperature range. Such a flexure-electrical effect occurs in any substance in the presence of a strain gradient. It was discovered that a.c. voltage arising on the sample faces normal to a strain gradient is directly proportional to the amplitude of sample vibrations and the sample thickness. A rather large value of a.c. voltage and its high temperature stability in the range of 20-200/spl deg/C for both materials under study may be interesting from an applications point of view.
18 Aug 1996
TL;DR: In this article, the effect of complex PbLi/sub 1/4/Sb/sub 3/4 /O/Sub 3/ (PLS) modifications on the mechanical quality factor and piezoelectric properties was investigated for several xBZZ-(1-x)PT compositions.
Abstract: The dielectric, piezoelectric, mechanical properties, and structure of the complex perovskite ceramics in the Bi(Zn/sub 1/2/Zr/sub 1/2/)O/sub 3/-PbTiO/sub 3/ system have been measured in the temperature range from 283 K to 900 K with the intention of utilizing them in electromechanical transducer applications. The effect of complex PbLi/sub 1/4/Sb/sub 3/4/O/sub 3/ (PLS) modifications on the mechanical quality factor and piezoelectric properties was investigated for several xBZZ-(1-x)PT compositions. Additions of PLS resulted in gradual lowering of mechanical quality factor. All the properties allow them to be used in broadband electroacoustic transducers, accelerometers, and vibration pickups operating over a wide temperature range.
23 Sep 1996
TL;DR: In this paper, a shallow water internal wave (SWIW) field model is proposed to estimate the stable sound field interference structure in the shallow water waveguide with internal waves, and the range-dependences of the full intensity, intensity of the coherent and noncoherent component of the sound field are investigated.
Abstract: The paper subject is the internal wave-induced acoustic fluctuations in a shallow water. The shallow water internal-wave (SWIW) field model offered is based on the experimental data and takes into account the basic features of the internal waves on a shelf. Within the framework of SWIW model the point source sound field in the shallow water waveguide with internal waves is considered. The range-dependences of the full intensity, intensity of the coherent and noncoherent (fluctuations intensity) component of the sound field are investigated. The distances on which the stable sound field interference structure may be observed (coherent distance) are estimated for two sorts of shallow water waveguides.
06 May 1996
TL;DR: In this paper, a simple expression for the dichroism in one-photon electron-atom scattering and spontaneous brenisstrahlung is presented, which shows that the effect may be observed experimentally.
Abstract: The differential cross sections of electron-atom collisions in a radiation field are different for right and left circular polarization of field. Simple expression for the dichroism in one-photon electron-atom scattering and spontaneous brenisstrahlung is presented. The numerical estimation of dichroism for one-photon Coulomb scattering shows thatthe effect may be observed experimentally. 1. INTRODUCTiON In the early experiments on interaction of laser radiation with atoms, the linear-polarized radiation was used as a rule, and polarization dependence of cross sections was not investigated. At present, the specific effects caused by polarization of radiation are rather well studied for bound-free and bound-bound transitions of electron, such as multiphoton ionization, level shift and splitting, optical harmonic generation."2 However, in free-free transitionsof electron-atom systems (for example, the stimulated bremsstrahlung and absorption) polarization effects have notbeen analyzed in detail.3
TL;DR: In this article, the electronic structure, local magnetic moments, and magnetic susceptibility of Fe, Co and Ni impurities in Al particles consisting of up to 100 atoms are calculated within the framework of the local spin-density approximation and the model of an "atom embedded in a jellium sphere".