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Cutting Performance and Mechanism of RE Carbide Tools

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Rare Metals 2001年第3期20卷 197-201页

作者： Jianbing Cheng, Yufang Wu, Qixun Yu 1) Department of Mechanical Engineering, beijing Technology and Business University, beijing 100037, china 2) College of Mechanical Engineering and Automation, beijing Institute of Technology beijing 100081, china beijing Technol & Business Univ Dept Mech Engn Beijing 100037 Peoples R China beijing Inst Technol Coll Mech Engn & Automat Beijing 100081 Peoples R China

The research of rare earth elements (RE), added into cemented carbide tools, is one of the recent developments of new types of tool materials in china. Systematic experiments about RE carbides YG8R. (K30), YT14R (P20) and, YW1R (M10) were made to study on the cutting performance in comparison with non-RE carbides YG8, YT14 and YW1. The cutting experiments were as follows: tool life, cutting force, tool-chip friction coefficient and interrupted machining. The action of RE on the carbide materials and the cutting mechanism of the RE carbide tools in the cutting process were verified with the aid of SEM and energy spectrum analysis. Experimental results show that the RE carbide tools have a good overall performance.

关键词： rare earth elements cemented carbide tool cutting performance cutting mechanism

NEW APPROACH TO THE LIMITER FUNCTIONS

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Journal of Computational Mathematics 1999年第1期17卷 41-58页

作者： Jin Li Ze-min Chen Zi-qiang Zhu(beijing University of Aeronautics and Astronautics, beijing 100083, china) beijing Univ Aeronaut & Astronaut Beijing 100083 Peoples R China

In this paper we discuss three topics on the designing of the limiter functions. (1) To guarantee the TVD property (2) To maintain enough artificial viscosity. (3) A method to form TVB limiter which can ensure second ... 详细信息

关键词： finite difference methods TVD schemes limiter function

The Carboniferous at the Northern Foot of the Dabie Mountains and Its Tectonic Implications

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Acta Geologica Sinica(English Edition) 1991年第3期65卷 237-249页

作者： Ma Wenpu china University of Geosciences, beijing Fei Zhenbi china University of Geosciences Beijing

In the Qinling orogenic belt. oceanic crust originated in the Early Palaeozoic. while the product of conti-nental collision appeared as late as after the Triassic. The Late Palaeozoic records there are of major impor-tance for understanding the tectonic regime at that time. The Carboniferous and even Permian sequences andthe distribution of sedimentary facies in northern Huaiyang indicate that the rocks were formed in a large basinopening towards the south. Regional stratigraphic correlation shows that the interior of the Qinling orogenicbelt was a sea trough lying between the Yangtze and North china plates in the middle part of the LatePalaeozoic. With subsequent northward migration of the South china Sea, the two seas were connected witheach other. Both the melanges and the Dabie block ia the eastern sector of the Qinling belt were formed in theMesozoic ?.

关键词： The Carboniferous at the Northern Foot of the Dabie Mountains and Its Tectonic Implications

DISTRIBUTION OF THE (0,∞) ACCUMULATIVE LINES OF MEROMORPHHIC FUNCTIONS

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Chinese Annals of Mathematics,Series B 1994年第4期15卷 453-462页

作者： WU SHENGJIAN(Department of Mathematics, beijing University,beijing 100871, china.) 北京大学数学系北京 100871

Suppose that f(z) is a meromorphic function of order and of lower order μin the plane. Let ρ be a positive number such that .(1) If f(l)(z) () has ρ() finite nonzero deficient values ai (i =1,…,p) with deficiencies δ(ai, f(l)), then f(z) has a (0, ∝) accumulative line of order inany angular domain whose vertex is at the origin and whose magnitude is larger than(2) If f(z) has only p ()(0, ∝) accumulative lines of order : arg z = θk (θ1<θ2…<θp<2π, θp+1 = θ1 + 2π), then , where , providedthat has a finite noasero deficient value.

关键词： Meromorphic function Accumulative line Order.

New progress in the principle of nonequilibrium statistical physics

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Chinese Science Bulletin 2001年第6期46卷 448-454页

作者： XING XiusanDepartment of Applied Physics, beijing Institute of Technology, beijing 100081, china Department of Applied Physics Beijing Institute of Technology Beijing China

In recent years, a new fundamental equation of nonequilibrium statistical physics was proposed in place of the Liouville equation. That is the anomalous Langevin equation in (?) space or its equivalent Liouville diffusion equation of time-reversal asymmetry. This equation reflects that the form of motion of particles in statistical thermody-namic systems has the drift-diffusion duality and the law of motion of statistical thermodynamics is stochastic in essence, but does not obey the Newton equation of motion, though it is also constrained by dynamics. The stochastic diffusion of the particles is the microscopic origin of macroscopic irre-versibility. Starting from this equation, the BBGKY diffusion equation hierarchy was presented, the hydrodynamic equations, such as the generalized Navier-Stokes equation, the mass drift-diffusion equation and the thermal conductivity equation have been derived succinctly. The unified description of all three level equations of microscopic, kinetic and hydrodynamic

关键词： anomalous Langevin equation in space drift-diffusion duality stochastic law nonequilibrium entropy evolution equation entropy diffusion.

Optimal reactions for the synthesis of superheavy nucleus ^(270)Hs

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Science china(Physics,Mechanics & Astronomy) 2006年第6期49卷 641-648页

作者： LIU Zuhua1,3 & BAO Jingdong1,2 1. Key Laboratory of Beam Technology and Material Modification of Ministry of Education, beijing Normal University, beijing 100875, china 2. Physics Department, beijing Normal University, beijing 100875, china 3. china Institute of Atomic Energy, beijing 102413, china Key Laboratory of Beam Technology Material Modification of Ministry of Education Beijing Normal University Beijing 100875 China Physics Department Beijing Normal University Beijing 100875 China china Institute of Atomic Energy Beijing 102413 China

The superheavy nucleus 270Hs is expected to be a “double-magic” deformed nucleus. We have calculated its cross sections of evaporation residue for the reactions 248Cm(26Mg,4n)270Hs, 244Pu(30Si,4n)270Hs, 238U(36S,4n)270Hs and 226Ra(48Ca,4n)270Hs using a two-parameter Smoluchowski equation. It is found from our results that 226Ra(48Ca,4n)270Hs and 238U(36S,4n)270Hs are two optimal reactions for the synthesis of the superheavy nucleus 270Hs due to their large negative Q-values.

关键词： diffused fusion barrier,Smoluchowski equation,superheavy nuclei.

HIGH ACCURACY NUMERICAL METHOD OF THIN-FILM PROBLEMS IN MICROMAGNETICS

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Journal of Computational Mathematics 2003年第1期21卷 33-40页

作者： Zhongyi Huang (Deft, of Mathematical Sciences, Tsinghua University, beijing, 100084, china) Dept. of Mathematical Sciences Tsinghua University 北京 100084

In this paper, a new high accuracy numerical method for the thin-film problems of micron and submicron size ferromagnetic elements is proposed. For the computation of stray field, we use the finite element method(FEM) by introducing a semi-discrete artificial boundary condition [1, 2]. In our numerical experiments about the domain patterns and their movement, we can see that the results are accordant to that of experiments and other numerical methods. Our method are very convenient to deal with arbitrary shape of thin films such as a polygon with high accuracy.

关键词： Thin-film Micromagnetics stray field Semi-discrete artificial boundary condition.

General expressions of peaked traveling wave solutions of CH-γ and CH equations

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Science china Mathematics 2004年第6期47卷 862-873页

作者： ZHANG WenlingDepartment of Mathematics and Physics, National Natural Science Foundation of china, beijing 100085, china 1. Department of Mathematics and Physics National Natural Science Foundation of China 100085 Beijing China

We use qualitative analysis and numerical simulation to study peaked traveling wave solutions of CH-γ and CH equations. General expressions of peakon and periodic cusp wave solutions are obtained. Some previous resul... 详细信息

关键词： peaked traveling waves general expressions numerical simulations

Feller property and exponential ergodicity of diffusion processes with state-dependent switching

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Science china Mathematics 2008年第3期51卷 329-342页

作者： XI FuBao Department of Mathematics, beijing Institute of Technology, beijing 100081, china 1. Department of Mathematics Beijing Institute of Technology Beijing 100081 China

In this paper we consider the Feller property and the exponential ergodicity for general diffusion processes with state-dependent switching. We prove their Feller continuity by means of intro- ducing some auxiliary processes and by making use of the Radon-Nikodym derivatives. Furthermore, we also prove their strong Feller continuity and their exponential ergodicity under some reasonable conditions.

关键词： Feller continuity Radon-Nikodym derivative strong Feller continuity exponential ergodicity state-dependent switching 60J60 34D25