排序方式: 共有27条查询结果,搜索用时 15 毫秒
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ZverovichIE ZverovichOI 《高校应用数学学报(英文版)》2004,19(2):125-132
Two new hereditary classes of P5-free graphs where the stability number can be found in polynomial time are proposed. They generalize several known results. 相似文献
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Karpov VI Dianov EM Paramonov VM Medvedkov OI Bubnov MM Semyonov SL Vasiliev SA Protopopov VN Egorova ON Hopin VF Guryanov AN Bachynski MP Clements WR 《Optics letters》1999,24(13):887-889
An all-fiber 1.48-mum generator based on a laser-diode-pumped Yb-doped double-clad laser and a cascaded Raman wavelength converter has been developed. Second-order Raman Stokes radiation was generated in a phosphosilicate-fiber resonator formed by two pairs of Bragg gratings. A slope efficiency of the Raman converter of 48% with respect to the power emitted by the double-clad Yb laser has been achieved. We obtained an output power of 1 W at a slope efficiency of 34% with respect to the laser-diode array power, with a total optical-to-optical efficiency of 23%. 相似文献
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A. S. Kurkov V. M. Paramonov O. I. Medvedkov I. D. Zalevskii S. E. Goncharov 《Laser Physics》2008,18(11):1234-1237
Raman-fiber source emitting 1450 nm with a power of 1 W was realized. The application of the commercially available pump source with an output power of 35 W allows one to increase the output power up to 5 W. The emission wavelength corresponds to the water absorption band therefore it is promising laser for the surgery and other medical applications. 相似文献
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L. B. Serezhkina E. V. Peresypkina A. V. Virovets Ya. A. Medvedkov V. N. Serezhkin 《Crystallography Reports》2014,59(1):48-52
Malonate-thiocyanate complex (NH4)3[UO2(C3H2O4)2(NCS)] · 2H2O is synthesized and studied by X-ray diffraction. The compound crystallizes in the monoclinic system: a = 13.9983(4) Å, b = 8.1947(2) Å, c = 16.4678(4) Å, β = 100.846(1)°, space group Cc, Z = 4, and R = 0.0158. The main structural units of the crystal are mononuclear [UO2(C3H2O4)2(NCS)]3? groups belonging to the AB 2 01 M 1 crystal chemical group of uranyl complexes (A = UO 2 2+ , B 01 = C3H2O 4 2? , M 1 = NCS?). Discrete uranium-containing groups are connected by electrostatic interactions with ammonium ions and by hydrogen bonds. Some specific structural features of crystals containing [UO2(L)2(NCS)]3? complexes, where L is the oxalate or malonate ion, are discussed. 相似文献
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Mashinsky VM Neustruev VB Dvoyrin VV Vasiliev SA Medvedkov OI Bufetov IA Shubin AV Dianov EM Guryanov AN Khopin VF Salgansky MY 《Optics letters》2004,29(22):2596-2598
Germania-glass-core silica-glass-cladding single-mode fibers (deltan as great as 0.143) with a minimum loss of 20 dB/km at 1.85 microm were fabricated by modified chemical-vapor deposition. The fibers exhibit strong photorefractivity, with type IIa index modulation of 2 x 10(-3). A Raman gain of 300 dB/(kmW) was determined at 1.12 microm. Only 3 m of such fibers is sufficient for constructing the 10-W Raman laser at 1.12 microm with a 13-W pump at 1.07 microm. 相似文献
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循环流化床气固曳力模型 总被引:1,自引:0,他引:1
气固曳力是稠密气固两相流动,尤其是垂直流动中的主要作用力,相应的模型也是数值模拟中准确描述气固两相运动的关键.为了解决现有经验或半经验模型的普适性问题,合理描述流动中经常发生的颗粒团聚现象及其对气固曳力的影响,从理论分析入手,运用最小能量的概念,将传统的CFD方法与宏观的系统分析方法相结合,建立了一个新的计及颗粒团聚效应的气固曳力理论模型.与现有模型相比,新模型不仅具有相同的函数变化关系,可合理地描述气固两相相互作用的物理过程,而且避免了以往经验系数不准确导致的各种误差,为稠密气固两相流动的数值描述提供了重要依据. 相似文献
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Ya. A. Medvedkov L. B. Serezhkina M. S. Grigor’ev V. N. Serezhkin 《Crystallography Reports》2016,61(3):383-390
Two new malonate-containing uranyl complexes with carbamide of the formulas [UO2(C3H2O4)(Urea)2] (I) and [UO2(C3H2O4)(Urea)3] (II), where Urea is carbamide, and one uranyl oxalate complex of the formula [UO2(C2O4)(Urea)3] (III) were synthesized, and their crystals were studied by X-ray diffraction. The main structural units in crystals I are the electroneutral chains [UO2(C3H2O4)(Urea)2]∞ belonging to the crystal-chemical group AT11M21 (A = UO22+, T11 = C3H2O42-, M1 = Urea) of uranyl complexes. Crystals II and III are composed of the molecular complexes [UO2(L)(Urea)3], where L = C3H2O42- or C2O42-, belonging to the crystal-chemical group AB01M31 (A = UO22+, B01 = C3H2O42- or C2O42-, M1 = Urea). The characteristic features of the packing of the uranium-containing complexes are discussed in terms of molecular Voronoi–Dirichlet polyhedra. The effect of the Urea: U ratio on the structure of uranium-containing structural units is considered. 相似文献
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Cumberland BA Popov SV Taylor JR Medvedkov OI Vasiliev SA Dianov EM 《Optics letters》2007,32(13):1848-1850
We report 33% efficient generation of the first Stokes in a high-concentration GeO(2) fiber Raman laser pumped by a 22 W thulium-doped fiber laser. An output power of 4.6 W at 2.105 microm is demonstrated. 相似文献
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Bufetov IA Firstov SV Khopin VF Medvedkov OI Guryanov AN Dianov EM 《Optics letters》2008,33(19):2227-2229
Bismuth-doped fiber lasers operating in the range 1300-1470 nm have been demonstrated for the first time, to our knowledge. It has been shown that Bi-doped alumina-free phosphogermanosilicate fibers reveal optical gain in a wavelength range of 1240-1485 nm with pumping at 1205, 1230, or 808 nm. 相似文献