Using a stochastic basis in signal and image recovery problems

This paper touches upon the problems of constructing a basis for stochastic functions, which represent samples of random numbers with a given distribution law. The algorithm for constructing an approximation model with the use of this basis is described. The general algorithm for signal recovery using the stochastic basis by the least squares method with a given weight function is given. The approach to solving the problem of recovery of blurred images with a known point scattering function by constructing an inverse filter model is proposed.     

Effect of copper on the properties of Pr-Dy-Fe-Co-B sintered magnets

The effect of copper on the properties of magnets (Pr_0.52Dy_0.48)₁₃(Fe₆₅Co_0.35)_{80.3 ? x} Cu _x B_6.7 (x = 0–10) has been studied. Alloying with copper is shown to decrease the sintering temperature and to increase the content of the principal (Pr,Dy)₂(Fe,Co)₁₄B magnetic phase. For compositions with x = 1.3–3.3, copper is found to affect the value and sign of the temperature induction coefficient (TIC). It is shown that the effect of copper on the TIC is determined by the substitution of copper ions for iron ions in lattice sites, which are coupled via an antiferromagnetic exchange interaction.     

Development of a method for calculating high-dimension heat networks

A transition from the mass balance equations based on Kirchhoff’s first and second laws to modeling on the basis of a discretized continuity equation is made for describing a hydraulic network. A technique for calculating high-dimension hydraulic and heat networks based on the numerical finite-difference control volume method is developed. Unlike the existing approaches, the proposed technique does not involve the need to determine hydraulic loops and boils down to solving the problem of obtaining a unified field of pressures for the entire calculation region. This advantage of the proposed method opens the possibility of applying it for solving high-dimension problems containing more than a million of hydraulic links. The proposed numerical method features stable operation for hydraulic networks the neighboring links of which may have pressure drop coefficients differing from each other by more than 10 orders of magnitude. In contrast, the global gradient algorithm implemented in the standard software system EPANET is of little use for such applications. The convergence rate of the proposed technique is close to that of the Todini gradient algorithm and is almost independent of the problem dimension.     

Tasks and methods of drawing up “The Program of Modernization of the Power Industry of Russia for the Period through the Year 2020”

The structure of tasks, stages, and methods of drawing up “The Program of Modernization of the Power Industry for the Period through the Year 2020” as part of the state program “Energy Efficiency and Development of the Energy Industry” have been determined.     

Development and study of robast control system for dc thyristor electric drive using polynomial techniques

Possibilities of polynomial techniques for synthesizing and analyzing a robast control system of dc thyristor electric drivers are considered. It is shown that the use of the suggested techniques makes it possible to decrease the sensitivity of a controlled electric drive to parametric, structural, and external disturbances by about an order of magnitude. A technique for optimizing the parametric sensitivity of the quality factors is suggested.     

Study of accessible free volume and transport properties of TFPS-co-TMSP copolymer

Copolymers of 1-trimethylsilyl-1-propyne (TMSP) with 1-(3,3,3-trifluoropropyldimethylsilyl)1-propyne (TFPS) as part of a systematic series with the TFPS content of the final polymer in the range of 0 to 46 mol % have been synthesized. The resulting samples have been characterized by different instrumental methods including NMR, IR, and DSC techniques. It has been shown that the accessible free volume of the polymer decreases from 30.4 to 19.1% with an increase in the proportion of TFPS units. Moreover, the gas transport properties of the membrane materials are reduced by factors of 30 (oxygen), 50 (nitrogen), and 15 (carbon dioxide), although the selectivity for the O₂/N₂ and CO₂/N₂ gas pairs increases from 1.6 to 2.5 and 2.5 to 11.5, respectively. A study of nanofiltration of organic media has shown that the ethanol permeability through the TFPS-co-TMSP copolymer material is reduced by no more than 30%, a value that is comparable with the relative decrease in the fractional free volume of the polymer. An increase in the TFPS content has improved the stability of the membrane material in ethanol (swelling ratio decreased from 61 to 39%), thereby resulting in an increase in the retention of the Orange II anionic dye (350 g/mol) from 89 to 94%.