Showing papers by "Voronezh State University published in 1994"

Optimal feedback control for a semilinear evolution equation

Abstract: In this paper, we consider a minimization problem of a cost functional associated to a nonlinear evolution feedback control system with a given boundary condition which includes the periodic one as a particular case. Specifically, by using an existence result for a system of inclusions involving noncompact operators (see Ref. 1), we first prove that the solution set of our problem is nonempty. Then, from the topological properties of this set, we derive the existence of a solution of the minimization problem under consideration.

The role of metabolic transformations in generation of biological order.

Abstract: Transformations of metabolic organization are considered as a ground of structure generation during ontogenesis and evolution. The emergence of non-linearity in metabolic pathways which leads to the formation of biochemical cycles is caused by the separation between the direct and reverse enzymatic reactions, one of them being coupled with the pool of macroergs, whereas the other--non-coupled. The absence of couplings in one of the halves of such primary cycle can lead to the increase of metabolic flow and to the generation of bifurcations resulting in the formation of new metabolic pathway. For their internalization the genetic reconstructions are necessary. Deposition of compounds from the cycles leads to the generation of internal rhythms and to morphogenetic processes. Morphology is formed by stable trajectories of the formation and deposition of certain compounds according to the principles of curvilinear symmetry.

Theoretical X‐ray Emission Study of High‐ Tc Superconductor YBa2Cu3O7 Thin Films

Abstract: The energy spectrum of YBa2Cu3O7 thin films is investigated by the film linearized augmented plane wave method (LAPW). On the basis of the results of the energy band structure calculation, theoretical calculations of X-ray emission spectra are performed. The calculated spectra are compared with the results of other calculations and experimental researches. The reason of the observed systematic discrepancies in the fine structure is analysed. The obtained spectra confirm the resonance character of the interaction of copper d-states with the nearest oxygen p-states. [Russian Text Ignored]

The Role of Accumulation in Forming the Nickeliferous Norite-Diorite Intrusions of the Voronezh Crystalline Massif

Abstract: This paper presents a generalized description of the composition (mineralogy and geochemistry of the rocks and ores) of the nickeliferous norite-diorite intrusions of the Yelan' complex of the Voronezh crystalline massif (European Russia). It is shown that the host norites have features of both ultramafic (substantial contents of MgO, Cr, and Ni; presence of highly magnesian olivine and orthopyroxene and highly chromian spinel) and intermediate rocks (substantial contents of SiO2, K, Rb, Ba, and light rare earth elements; presence of K-feldspar, quartz, and low-calcium plagioclase). The ores have relatively low Cu/Ni and Pd/Ir ratios, are enriched in Mo, Sb, Bi, Se, Te, As, Ag, and Au, and have anomalous sulfur and carbon isotopic compositions. These unique features of the composition are interpreted from the standpoint of an assimilation model proposed by the authors. It is shown that the formation of the norite-diorite intrusions was related to assimilation of silicic rocks of the continental crust by a...

Kinetic description of the oxidation of hydrocarbons inhibited by sulfur-containing hydrogenated quinolines

Abstract: The inhibiting effect of dithiolthione derivatives of hydrogenated quinolines (DTT) on the oxidation of various hydrocarbons (n-decane,n-decene, ethylbenzene, β-carotene) was investigated. The inhibiting effect of the DTTs is greater at high temperatures (>100 °C) than that of the parent hydrogenated quinolines and weaker at moderate temperatures. The DTTs do not affect the decomposition of hydroperoxides. Probably, the introduction of a dithiolthione cycle to a hydroquinoline molecule decreases its reactivity toward O2 and peroxide radicals, which favors the enhancement of the antioxidative activity of the DTTs at elevated temperatures.

The domain mechanism of aging and degeneration of ferroelectric material

Abstract: The mechanism of interactions of domain boundaries in ferroelectric-ferroelastic crystals with different (uncharge, charge and elastic types) defects are investigated. The diffusion of defects to boundaries and the processes of the domain walls interacting with defects are studied. The values of domain contribution in dielectric permeability and the coercive field determined by the storage time and the number of switching cycles for the material with initial random defect distribution are calculated.

On the construction of non-stationary orthonormal infinitely differentiable compactly supported wavelets

Abstract: An approach for the construction of non-stationary orthonormal wavelets is presented. The method allows to obtain non-stationary orthonormal infinitely differentiable compactly supposed wavelets. Furthermore, the support width of the generator of the level j in this system is less then 2t(j+2)2/sup -j/, where {t(j)} is a sequence of integers satisfying the conditions: lim/sub j/spl rarr//spl infin//t(j)=/spl infin/, t(j)/spl les/t(j+1)/spl les/t(j+1), t(1)=1.

On self-adjoint operators connected by inequalities and on their applications to problems of mathematical physics

Abstract: D(A) with respect to the seminorm ([A[x, x) 1/2 (x E D(A)). Let A0 and A1 be closed symmetric operators with D[A0] C H and D[A1] C H, and let [., "]0 and [., "]1 be extensions by continuity (on the possibility of such an extension see Proposition 2 below) of the forms (Ao-, ") and (AI-,-) on D[A0] and DIAl], respectively. We say that A0 precedes A1 and denote Ao -< Ai, if [x,X]o < Ix, x]1 for z e D[A0] f'l DIAl]. In the sequel, A0 and A1 are assumed to be partially invertible self-adjoint operators. Our purpose is to study properties of the inverse operators Ao 1 and A~ -1 and also "intermediate" operators A : A0 -< A -~ A1. Several statements proved in [2-4] for bounded operators, connected by inequalities, follow directly from the results stated below. For some applications, similar statements, obtained by means of very different methods (the Galerkin method, the alternative Cesari method in combination with the monotone operator method, and also considerations related to the power of nonlinear operators), can be found in [5, 6]. 2. Before formulating basic results, we prove the following simple propositions important in the sequel. Proposition 1. Let A be a closed symmetric operator with a dense domain D(A). Then D[A] C H if and only if the range R(A) of values of the operator A is closed. Moreover, D[A] = D(tAt]/2). Proof. From the closeness and symmetry of the operator A it follows that its kernel Ker A is a subspace, I,:er A C KerA*, R(A) C R(A*). Since H = KerA@R(A*), we see that the operator Ag_ := AID(A ) N R(A*) is closed, symmetric, dense definite in R(A*), and acting in it. The equality D[A] = Ker A @ D[A2] tbllows directly from the definition of DIAl. Therefore, the inclusions D[A] C H and D[A2] C H hold only simultaneously. This enables us to assume without loss of generality that Ker A = {0}. Let R(A) = R(A). Then IAI is a partially invertible operator on H. Consequently, D(IAI 1/2) is a Hilbert space with the scalar product ([dl~/2x, Idll/2y) (x,y E D(Idll/2)). Since (Idll/2x, Idl~/2y) = (Idlz, y) for x e D(A) (= D(Idl)), we see that the lineal D(A) is dense in D(Idl 1/~-) with respect to the scalar product (]d[1/2x, Idll/2y). By definition, D[d0] = D(Idl 1/2) C g. Let R(A) 5~ R(A). Then ,~ = 0 is a point ofthe continuous spectrum of the operator [AI. We denote by A a finite half-interval which contains the point ,\ = 0, and by H(A) the corresponding spectral invariant subspace of the operator IAI. Now we consider the operator A(A) = IAI I H(A). It is a bounded completely invertible positive operator. Since D(A(A)) = H(A), we have H(A) C_ D[A(A)]. What is more, it follows from the known Banach theorem on the norm equivalence that D[A(A)] r H(A). From this and the inclusion D[A(A)] C D[d] we have D[A] ~ H. Note that if A is a closed symmetric extension of the operator A and DIAl C H, then not always Did] C H. This follows from the existence of symmetric operators A with R(A)  R(A), which have symmetric extensions A with R(A) = R(A). For details on such operators and the corresponding criteria see [7].

Dielectric properties of strontium and lead based complex perovskite ceramics

Abstract: The dielectric properties and structure of the complex perovskite ceramics (07PbZrO/sub 3/-03K/sub 05/Bi/sub 05/TiO/sub 3/)+xSrTiO/sub 3/ have been investigated in the temperature range from 283 K to 333 K with the intention of understanding a change of a sign which occurs in the temperature coefficient of the capacitance at x/spl sime/05

Some predictions of new spontaneous cluster emitters and mechanism of cluster decay

Abstract: Two basic mechanisms of cluster radioactivity are discussed. The theoretical predictions for the new region of cluster emitters withA ∼ 110 are reported. The preliminary experimental results have indicated in favour of a nonadiabaticα-decay-like mechanism developed by the authors earlier.

Hyper-raman scattering by polarized atoms and molecules

Abstract: 499 (1976); V. M. Klimentjev et al., JETP Lett. 24, 8 (1976); L. T. Bolotskikh et al. ADDL Phvs. 835, 249 (1984); V. G. & h i p k k et al. Kvant. Elektron. 13, 1352 (1985). 2. T. Ya. Popova et al. Sov. Phys. JETP 57, 444 (1969); Yu. M. Kirin et al. JETP Lett. 9, 7 (1969); JETP, 62, 466 (1972); M. P. Bondareva et al. Opt. Spektrosk. 38, 219 (1975). 3. Yu. I. Heller, A. K. Popov, Opt. Commun. 18, 449 (1976); l'hys. Lett., 50A, 453 (1976); S. E. Harris et al. Phys. Rev. Lett. 64, 1107 (1990). V. G. Arkhipkin, A. K. Popov, A. S. Aleksandrovsky (To be published, also submitted to EQEC'94.) A. K. Popov, Introduction to Nonlinear Spectroscopy (in Russ.) (Novosibirsk, Nauka, 1983); T. Ya. Popova et al. Sov Phys. JETP 57, 850 (1969); Yu. I. Heller, A. K. Popov, Joum. Sov. Laser Research, 6, 1-84. (Plenum, New York, Jan.-Feb., 1985. 4.

Average decay law of sound intensity and surface noise vertical angular distribution in waveguide with random inhomogeneities

Abstract: Analytical expressions for average decay law are obtained on the basis of a model for sound propagation in shallow water with random inhomogeneities. The directionality of vertical surface noise is also considered. >

Zeeman effect for molecular rydberg states

Abstract: are taken into consideration. It means that we include the molecular core quantum numbers such as spin, rotational moment, etc.) into the theory. In this case, in addition to the above-mentioned relativistic correction, we must consider the orbit-axial, spin-axial, spin-rotational and spin-spin interactions. Which of these interactions yields a significant contribution depends on which coupling case is under consideration. Because the system “molecular core + Rydberg electron” is characterized by more than 3 angular moments, the usual Hund’s coupling cases should be generalized. The formulae describing the correspondent fine structure can be written for each generalized coupling case. These data may be applied to describing the continuous transition from the Zeeman effect to Pashen-Back effece as well as to several important problems of the Rydberg molecules spectroscopy But the form (1) of solution is more convenient for digonalization the spin-orbital terms (which are also of interest when describing the continuous transition from the Zeeman effect to Pashen-Back effecp). 1. B. A. Zon, Zh. Eksp. Teor. Fiz. 102, 36 (1992). 2. B. A. Zon, D. L. Dorofeev, Report to this Conference. 3. B. A. Zon, D. L. Domfeev, V. E. Chemov, Report to this Conference.

Rotational rydberg states in dipole molecules

Abstract: are taken into consideration. It means that we include the molecular core quantum numbers such as spin, rotational moment, etc.) into the theory. In this case, in addition to the above-mentioned relativistic correction, we must consider the orbit-axial, spin-axial, spin-rotational and spin-spin interactions. Which of these interactions yields a significant contribution depends on which coupling case is under consideration. Because the system “molecular core + Rydberg electron” is characterized by more than 3 angular moments, the usual Hund’s coupling cases should be generalized. The formulae describing the correspondent fine structure can be written for each generalized coupling case. These data may be applied to describing the continuous transition from the Zeeman effect to Pashen-Back effece as well as to several important problems of the Rydberg molecules spectroscopy But the form (1) of solution is more convenient for digonalization the spin-orbital terms (which are also of interest when describing the continuous transition from the Zeeman effect to Pashen-Back effecp). 1. B. A. Zon, Zh. Eksp. Teor. Fiz. 102, 36 (1992). 2. B. A. Zon, D. L. Dorofeev, Report to this Conference. 3. B. A. Zon, D. L. Domfeev, V. E. Chemov, Report to this Conference.

Semiconductor depolarizer for multimodel laser radiation

Abstract: A number of the experimental optical investigations require operating with unpolarized laser beams. But the currently available devices for depolarization of the laser beam (for instance, by means of multiple reflection from a number of variously oriented phase plates) are rather inconvenient. We suggest here a new method of depolarization for the laser radiation which frequently has multimodal structure. This method is based on the phenomenon of nonlinear light depolarizat i~n ' -~ that always takes place when the multimodal laser radiation propagates through a nonlinear medium. Due to the multimodal structure of the incident laser radiation, the depolarization is connected with the fact that the polarization parameters depend on the fluctuating intensity of the radiation in nonlinear media. We obtain the partially polarized radiation when the nonlinear relaxation time T is much less than T, the time of laser intensity correlation.

Calculation of the characteristics of the sound propagated in the shallow water and reconstruction of bottom parameters using acoustical data

Abstract: A general shallow water model and sound field characteristics calculation method are presented. A comparison of theoretical and experimental data was made. >