Research system of decision making by composite image fragments using neuron-like algorithms

Base models of homogeneous neuron-like media and the corresponding systems of spatiotemporal solutions are considered. Ways of using these models and solutions as the base models for designing hierarchic systems of parallel processing of complex information flows with the help of neuron-like algorithms are studied. The version of a decision-making system with tunable architecture at a coarsegrain level (for adapting the system to the processing purposes and type of image) and universal neuron-like subsystems at a fine-grain level (for providing a wide variety of operations needed to extract local and global features and to encode individual fragments or the whole of the image) is developed. Examples of the transformation processes in the images of biological objects (growing neurons, erythrocytes, fingerprints) in a hierarchic decision-making system are demonstrated.Institute of Applied Physics, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 8, pp. 961–986, August, 1994.     

Excitation spectra of a system of two coupled quantum wells

Quasi-particle spectra, reconstructed by e-h pairing, have been calculated for a system of spatially separated electrons (e) and holes (h) in ground state. The regions of strong pairing interaction and significant correlation effects are reached by abandoning the BCS approximation and using instead interpolation expressions for correlation energies, which depend functionally on the coefficients of the u-v transformation, with subsequent minimization of the total energy of the reconstructed state with respect to the parameters of the u-v transformation. The dependence of the spectra on quantum-well separation and particle concentration in a system of two coupled quantum wells is discussed. Fiz. Tverd. Tela (St. Petersburg) 40, 2226–2228 (December 1998)     

Wave propagation in an excitable medium with a negatively sloped restitution curve

Recent experimental studies show that the restitution curve of cardiac tissue can have a negative slope. We study how the negative slope of the restitution curve can influence basic processes in excitable media, such as periodic forcing of an excitable cell, circulation of a pulse in a ring, and spiral wave rotation in two dimensions. We show that negatively sloped restitution curve can result in instabilities if the slope of the restitution curve is steeper than -1 and report different manifestations of this instability. (c) 2002 American Institute of Physics.     

Theoretical Concept of Nonbranched Radical-Chain Reactions Involving Catalysts

The foundations of the theoretical concept of nonbranched radical-chain reactions involving heterogeneous catalysts are considered for hydrocarbon pyrolysis. These include the phenomenological model and the concept of the catalysis sphere. Surface active sites S participate in chain propagation along with hydrocarbon radicals R^· from the gas phase. Surfaces show either inhibiting or neutral action depending on the E _S–R bond energy. If the E _S–R value is comparable with the energy of the breaking bond in the reacting molecule, the reaction accelerates due to the acceleration of either the heterogeneous or homogeneous component of the overall rate of the process. In the latter case, the catalyst ensures the generation of additional radicals for the gas phase, which result in the formation of a catalysis sphere. The catalysis sphere is defined, the radical distribution in it is presented, and its properties and role in radical-chain processes are discussed.     

Inhibition of the alkaline corrosion of cement materials with additions of ultradispersed silica

Efficiency of ultradispersed and colloidal silica-containing materials as inhibitors of the alkaline corrosion of cement formulations containing reactive fillers was studied. It was found that the dispersity of the silica-containing materials affects their inhibiting capacity.     

Averaged model with capillary nonequilibrium effects for two-phase flow through a highly heterogeneous porous medium

Two-phase flow through a medium with two porosities in which the absolute permeabilities and the capillary pressure functions of the components differ by an order of magnitude is investigated. A classification and diagram of the elementary flows are proposed at the single cell level. An averaged model is developed for a single class of systems in which source-type capillary-dispersion flow predominates in the blocks. This model contains a nonlinear kinetic relation between the average values of the capillary pressure functions. An expansion of the effective phase permeability tensor allowing it to be calculated efficiently is proposed. The capillary relaxation time is explicitly determined. Examples of calculations of the averaged phase permeability tensor and the capillary relaxation time are given. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 93–103, May–June, 1998. The work was carried out with the support from the Russian Foundation for Basic Research (project No. 95-01-01179a).     

Transient boundary layer effect in underground oil and gas reservoir depletion processes

Modern methods of exploiting underground deposits of oil and gas are characterized by conditions that vary slowly with time, which makes it possible to treat them over an extended period as near-equilibrium processes and use for their analysis the effective methods of perturbation theory. At the same time, during a brief initial period these systems display essentially nonequilibrium behavior leading to a transient boundary layer effect. For closed reservoir depletion problems a measure of the degree of nonequilibrium of the reservoir system is introduced and for real deposits shown to be small, the existence of a boundary layer is established, and the exterior and interior problems are formulated, together with the matching conditions. The general form of the exterior asymptotic behavior, in which the space variables and time are separated, is established and the initial parabolic system is reduced to a linear Poisson equation. Examples of problem solving are given.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 72–77, November–December, 1985.     

EPR investigation of a-Si:H aerosol particles formed under silane thermal decomposition

The dangling bond defects were investigated in a-Si:H particles formed under silane thermal decomposition in flow reactor. EPR together with hydrogen evolution method were used. The experimental results allowed us to conclude that there are two kinds of dangling bond defects in a-Si:H aerosol particles. The defects of the first kind are localized on the surface of interconnected microvoids and microchannels (surface dangling bonds) and those of the second kind are embedded in amorphous silicon network (volume dangling bonds). The thermal equilibration of dangling bonds and temperature dependence of equilibrium dangling bond concentration were investigated. It was found that at temperatures > 400 K the dangling bond concentrationNApplied Magnetic Resonance _s reversibly depends on sample temperature. The volume dangling bond concentration increases with temperature increasing (the effective activation energy of dangling bond formationU > 0), and the surface dangling bond concentration decreases with temperature increasing (U < 0). It has been found that EPR line is considerably asymmetric for samples with high hydrogen content and for low hydrogen content the EPR line is weakly asymmetric. A conclusion was drawn that the asymmetry degree depends on amorphous silicon lattice distortions. This conclusion has been confirmed by EPR spectra simulations.