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1.
An antenna array for wideband operation (up to 70%) is presented. The structure has low windloading area and consists of parallel printed circuit boards (PCB) with microstrip dipoles, feed network and metal fences placed between the PCBs. The low profile, low weight antenna array forms the main beam and three difference patterns for sidelobe cancellation. Experimental results are compared with calculations for both microstrip dipole and array 相似文献
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E. A. Timofeev 《Cybernetics and Systems Analysis》1991,27(4):540-548
The generating function of the number of customers in a GI|HM2|1 queue is derived for a service discipline which is a stochastic mixture of absolute and relative priorities.Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 75–84, July–August, 1991. 相似文献
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A. V. Solokhin S. L. Nazanskii V. S. Timofeev 《Theoretical Foundations of Chemical Engineering》2005,39(2):105-109
The evolution of the phase portrait for the dynamic system of open evaporation combined with a chemical reaction for a fixed liquid amount was studied as dependent on the rate constants of the reaction. A three-component azeotropic mixture whose vapor-liquid equilibrium diagram is characterized by two distillation regions was considered. The possibility of the open evaporation trajectory to transfer through the separatrix between the distillation regions was shown, as well as the possibility of implementing the principle of redistribution of the concentration fields due to chemical reactions occurring in reactive distillation columns.Translated from Teoreticheskie Osnovy Khimicheskoi Tekhnologii, Vol. 39, No. 2, 2005, pp. 115–119.Original Russian Text Copyright © 2005 by Solokhin, Nazanskii, Timofeev. 相似文献
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E. M. Gavrishchuk E. Yu. Vilkova O. V. Timofeev U. P. Borovskikh E. L. Tikhonova 《Inorganic Materials》2007,43(6):579-583
Chemical interaction between polished surfaces of polycrystalline zinc selenide and inorganic acid solutions of various concentrations has been studied. 相似文献
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V. V. Vavilova V. M. Ievlev A. P. Isaenko Yu. E. Kalinin Yu. K. Kovneristyi N. A. Palii B. G. Sukhodolov V. N. Timofeev 《Inorganic Materials》2003,39(1):72-76
The effect of pulsed photon annealing with energy densities from 1.4 to 42 J/cm2 for various lengths of time on the structure of the amorphous alloy Fe79P14.2Si4.4Mn2.2V0.2 was studied by x-ray diffraction, differential scanning calorimetry, and transmission electron microscopy. The results demonstrate that short-term irradiation with low energy densities leads to surface relaxation of the amorphous alloy, increases the strength of the surface layer, and reduces the internal-friction peak. Longer term photon annealing leads to crystallization of the alloy throughout the sample thickness. 相似文献
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Gavrilovic P. Timofeev F.N. Haw T. Williams J.E. 《Quantum Electronics, IEEE Journal of》1991,27(7):1859-1862
Data on long-cavity 100-μm-wide broad-stripe laser diodes that lase with a barrow single-lobed far-field pattern in continuous room-temperature operation are presented. Diodes with a cavity length of 1250 μm emit a power of 200 mW per facet into a 2.5° lobe (full width at half maximum). Short-cavity devices (cavity length of 350 μm) lase with a continuously increasing number of lateral modes right from threshold, and exhibit a far-field divergence that is over three times greater than that of 1250-μm diodes. Explanations for the effect of increasing cavity length on the field patterns of these devices are proposed, based on the measured increase in injected carrier diffusion length in long-cavity diodes and the influence of thermal waveguiding and mirror losses on intermodel discrimination 相似文献
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