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A method for calculating the distance characteristic of optoelectronic systems is proposed which provides increased accuracy in comparison with known techniques. Theoretical results are compared with experimental data.

Algorithms for improving the resolution of a sequence of images distorted by applicative noise manifested in the form of randomly shaped local regions of occlusion are synthesized and analyzed. The basis is the implementation of an optimal linear filtering algorithm in block form, which is synthesized with account for possible emergence of false observations in individual elements of the analyzed images. A method for incorporating the results of independent segmentation of each individual image into the recursive filtering process is proposed, which enhances the quality of the final processing.

This paper describes the structure and control algorithms of a controller of a high-voltage source with an output voltage of 60 kV and a power of up to 30 kW. The source is designed to be used as part of a power unit of an electron-beam welding device developed at the Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences (BINP SB RAS). High-quality welds require a stable electron beam energy. Herewith, a standard operation mode is quick and deep modulation of the electron current. The problem of achieving high-quality control and limiting the transient distortions of output voltage of the source is solved. The error of establishing and stabilizing the output voltage is 0.1%, which allows obtaining high-quality welding. Transient distortions at 100% modulation of the load current do not exceed the value of ±1%, which, along with fast reaction of the source to a load breakdown (energy released during breakdown is smaller than 15 J), protects the welded parts and elements of the gun from being damaged by an electron beam.

This paper describes the analysis of analog-digital converters operating in positional and nonpositional number systems. A new method for analog-digital conversion on the basis of the features of a modular number system is proposed.

A three-dimensional supersonic turbulent flow withsymmetric normal injection of circular jets from the channel walls isnumerically simulated. The initial Favre-averaged Navier-Stokesequations closed by the $k$--$\omega$ turbulence model are solved by analgorithm based on an ENO scheme. The mechanism of the formation ofvortical structures due to the interaction of the jet with the freestream is studied for jet to crossflow total pressure ratios rangingfrom 3 to 50. It is known from experiments reported in the literaturethat, for $n\ge 10$, mixing of the jet with the high-velocity flowleads to the formation of a pair of vortices and of an additionalseparation zone near the wall behind the jet. It is demonstrated thatthe present numerical results are consistent with such findings andthat the pressure distribution on the wall ahead of the jet in theplane of symmetry is also in reasonable agreement with availableexperimental data.

A functional mathematical model of a hydrogen-driven combustion chamber for a scramjet is described. The model is constructed with the use of one-dimensional steady gas-dynamic equations and parametrization of the channel configuration and the governing parameters (fuel injection into the flow, fuel burnout along the channel, dissipation of kinetic energy, removal of some part of energy generated by gases for modeling cooling of channel walls by the fuel) with allowance for real thermophysical properties of the gases. Through parametric calculations, it is found that fuel injection in three cross sections of the channel consisting of segments with weak and strong expansion ensures a supersonic velocity of combustion products in the range of free-stream Mach numbers $\mboxM_\infty = 6\mbox--12$. It is demonstrated that the angle between the velocity vectors of the gaseous hydrogen flow and the main gas flow can be fairly large in the case of distributed injection of the fuel. This allows effective control of the mixing process. It is proposed to use the exergy of combustion products as a criterion of the efficiency of heat supply in the combustion chamber. Based on the calculated values of exergy, the critical free-stream Mach number that still allows scramjet operation is estimated.

The operation of an electromagnetic multirail launcher of solids powered from a pulsed magnetohydrodynamic (MHD) generator is studied. The plasma flow in the channel of the pulsed MHD generator and the possibility of launching solids in a rapid-fire mode of launcher operation are considered. It is shown that this mode of launcher operation can be implemented by matching the plasma flow dynamics in the channel of the pulsed \hboxMHD generator and the launching conditions. It is also shown that powerful pulsed MHD generators can be used as a source of electrical energy for rapid-fire electromagnetic rail launchers operating in a burst mode.

Theproblemofflowsinitiatedbyvertical lifting of a rectangular beam partially submerged in shallow water filling a rectangular prismatic channel with a horizontal bottom is studied in the long-wavelength approximation. The width of the beam is equal to the channel width, and its upper and lower planes are parallel to the channel bottom. In the first stage of the flow, the lower surface of the low beam is completely submerged in the liquid, which is lifted after it by hydrostatic pressure. Conditions for the well-posedness of this problem are obtained, and solutions describing the liquid flow in the region adjacent to the bottom surface of the beam and in outer regions with a free upper boundary are constructed for different laws of lifting of the beam.

This paper is a review of studies carried out on the basis of two-dimensional boundary-value problems of filtration theory. The role of critical regimes determining the specifics of filtration flows with moving boundaries is noted.

Gas filtration from an underground reservoir through a layer of a porous medium due to an instantaneous increase in the gas pressure in the reservoir is studied. The problem is considered in a one-dimensional formulation in the general case where the temperatures of the gas and the porous medium are different and unstable, and in the case of a high specific heat of the solid phase and a high interfacial heat-transfer rate. The dynamics of the gas flow at the inlet and outlet of the underground reservoir is analyzed, the time of unloading of the system is estimated as a function of the permeability of the porous medium. It is shown that, depending on the properties of the porous layer, two characteristic gas flow regimes are possible: a fast discharge regime and a slow regime which is determined mainly by barodiffusion.