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3篇 您的检索式:作者名="2 Faculty of Science,Jiangsu University,Zhenjiang 212013,China"
    题名 作者 年代 出处 被引量
1The low-mass X-ray binary-millisecond radio pulsar birthrate problem revisited显示文摘We investigate the birthrate problem for low-mass X-ray binaries(LMXBs) and millisecond radio pulsars(MRPs) in this paper.We consider intermediate-mass and low-mass X-ray binaries(I/LMXBs) to be the progenitors of MRPs,and calculate their evolutionary response to the cosmic star formation rate(SFR) both semi-analytically and numerically.With a typical value(1 Gyr) of the LMXB lifetime,one may expect comparable birthrates of LMXBs and MRPs,but the calculated number of LMXBs is an order of magnitude higher than that observed in the Galaxy.Instead,we suggest that the birthrate problem could be solved if most MRPs have evolved from faint to rather than bright LMXBs.The former may have a population of-104 in the Galaxy.DAI HaiLang1,2 & LI XiangDong2 1 Faculty of Science,Jiangsu University,Zhenjiang 212013,China 2 Department of Astronomy,Nanjing University,Nanjing 210093,China 2010Science China(Physics,Mechanics & Astronomy)2010,53,S1:0
2Strong law of large numbers for Markov chains indexed by an infinite tree with uniformly bounded degree显示文摘In this paper,we study the strong law of large numbers and Shannon-McMillan (S-M) theorem for Markov chains indexed by an infinite tree with uniformly bounded degree.The results generalize the analogous results on a homogeneous tree.HUANG HuiLin~1 YANG WeiGuo~(2+) 1 Department of Mathematics,Shanghai Jiaotong University,Shanghai 200240,China 2 Faculty of Science,Jiangsu University,Zhenjiang 212013,China 2008Science China Mathematics2008,51,2:23
3Equilibrium equations for nonlinear buckling analysis of drill-strings in 3D curved well-bores显示文摘With the development of drilling technology, the oil/gas well has evolved from its early vertical straight form to the inclined, horizontal, plane curved, or even 3D curved well-bore. Understanding of the buck- ling behavior of a drill-string in a well-bore is crucial for the success of a drilling operation. Therefore, equilibrium equations for analyzing the buckling behavior of a drill-string in a 3D curved well-bore are required. Based on Love’s equilibrium equations for a curved and twisted rod in space, a set of equi- librium equations for the nonlinear buckling analysis of a drill-string in a 3D curved well-bore are de- rived by introducing a radial constraint of the well-bore. The proposed formulae can account for the well curvature and tortuosity. Thus, it can be used to analyze the buckling behaviors of a drill-string constrained in a well-bore and subjected to axial compression, torsion at its upper end, and gravity simultaneously. It is worth noting that the existing equations in the literature for a drill-string in a straight and plane curved well-bore with a constant curvature are a special case of the proposed model. Thus, the present model can provide a theoretical basis for the nonlinear buckling analysis of a drill-string constrained in a 3D curved well-bore.TAN MeiLan1 & GAN LiFei2 1 Faculty of Science, Jiangsu University, Zhenjiang 212013, China 2 94973 Unit in Hangzhou of Zhejiang Province, Hangzhou 310021, China 2009Science China(Technological Sciences)2009,52,3:7
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