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991.
P. I. Stetsyuk 《Cybernetics and Systems Analysis》2006,42(1):54-64
New quadratic models are proposed to improve the upper-bound estimates in the maximum weighted cut problem. They are found
by two original methods for deriving redundant quadratic constraints. A well-known linear model is shown to follow from the
models proposed. Recommendations on how to develop its strengthened analogs are given.
This study is partially sponsored from the grant UM2-2574-KV-03 (CRDF Cooperative Grants Program).
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 1, pp. 63—75, January–February 2006. 相似文献
992.
A. V. Shchedrin V. V. Ul’yanov V. M. Skoromnov A. A. Bekaev Z. I. Egorova 《Metallurgist》2006,50(9-10):542-547
Results are presented from extensive comparison studies of drawing operations performed with the use of drawplates whose working surfaces have an irregular or regular microroughness. Regularizing the microroughness of the working part of the drawplate makes it possible to control the dimensional accuracy of the resulting products within broad ranges of values. 相似文献
993.
A circuit design is proposed and the possibilities for incorporation of an input double-notch low-frequency ripple filter are considered. Recommendations regarding the use of mathematical models for the calculation of transient processes in a DC electric-traction network are given. An analysis of the simulation of processes in a low-frequency filter shows that the emission of interference by the electric rolling stock should be estimated using the wavelet analysis since this approach best suits the studies of nonstationary signals. 相似文献
994.
Hemmatjou H. Farzaneh M. Fofana I. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2007,14(6):1390-1400
A mathematical model for predicting the ac flashover voltage of snow-covered insulators is presented. The arc constant parameters in air gaps and inside snow, as well as the arc reignition condition are determined using a cylindrical model. The effects of the arc length on the arc constants parameters are also investigated. The model is then applied to an EPDM insulator artificially covered with natural snow. There is good concordance between the flashover results determined from the mathematical model and those obtained experimentally. 相似文献
995.
A. V. Pavlenko V. P. Grinchenkov A. A. Gummel I. A. Pavlenko E. Kallenbakh 《Russian Electrical Engineering》2007,78(4):190-197
The design principals of fast-operating electromagnetic drives with prescribed dynamic performances are examined. The represented procedure permits the command parameters to be to determined with the guaranteed prescribed parameters of the drive. 相似文献
996.
The effect of the growth dynamics of heterotrophs on the composition and properties of peat lipids was demonstrated. Microbiological processes resulted in a considerable change in the amounts of water-soluble polysaccharide and polyphenol fractions. The lipid content remained practically unchanged under various model experiment conditions. In this case, an increase in the concentration of alkanes and the antioxidant activity of lipids was observed. The accumulation of antioxidants and an increase in the amount of chrysenes in lipids support the role of a microbiological factor in the origin of hydrocarbons. 相似文献
997.
A. I. Rabukhin 《Glass and Ceramics》2007,64(7-8):226-228
Equations are proposed for calculating the concentrations of structural groups with constant composition (SGC) in borate glasses,
containing modifier oxides from the first and second groups of the periodic table. The partial molar volumes of SGC are determined
and the molar volume of glasses from the systems indicated is calculated using the additive approximation formula. The computed
values of V
m
satisfactorily approximate the experimental data obtained by different authors — the maximum standard computational error
does not exceed 2.5%.
__________
Translated from Steklo i Keramika, No. 7, pp. 7–9, July, 2007. 相似文献
998.
A. G. Upolovnikova V. M. Chumarev R. I. Gulyaeva L. Yu. Udoeva 《Russian Metallurgy (Metally)》2007,(1):10-13
The effect of sodium carbonate additions on phase formation during the air oxidation of the sublimates of niobium electron-beam remelting is studied by derivatography, X-ray diffraction analysis, and electron-probe microanalysis. The composition of the oxidation products changes with the heating temperature. The formation of sodium niobates and aluminates is detected by X-ray diffraction analysis at temperatures higher than 600°C. The oxidation of the sublimates is completed by the formation of sodium metaniobate and aluminate. Sodium carbonate additions are shown to accelerate the oxidation of the sublimates. 相似文献
999.
M. N. Chepurnoi V. É. Shnaider N. I. Sinyuk 《Journal of Engineering Physics and Thermophysics》1987,52(6):662-665
Experimental data on the loss of liquid from the surface of a film and the resistance of dispersed-annular flow are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 52, No. 6, pp. 925–929, June, 1987. 相似文献
1000.
The blast furnace in the blast-furnace shop at the West Slovakian Metallurgical Combine is charged by means of a complex system
that usually includes the following: an ore yard with a hopper gantry; a system to collect, weigh, and transport the charge
materials to the top of the furnace; the charging apparatus of the furnace; a system that controls the charging operation.
The use of continuous-acting mechanisms facilitates charging of the ore-bearing materials in the charge while minimizing the
content of the −5-mm fraction of these components and the number of coke particles smaller than 25 mm. The productivity of
the furnace could be increased further, which would allow the addition of an efficient aspiration system and make it easier
to fully automate the furnace.
__________
Translated from Metallurg, No. 7, pp. 45–46, July, 2006. 相似文献