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Electron transmission and quantum current distribution of C_(70) molecule

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Science China(Physics,Mechanics & Astronomy) 2008年第2期51卷 126-132页

作者： KATSUNORI Tagami3.MASARU Tsukada Nano Technology Research Centre 120-5 Waseda University

The characteristics of electron transmission through C70 molecule bridge in which two atomic chain leads are connected to long-axis carbon atoms are investigated theoretically by using tight-binding approach based on the Green's function with only one π orbital electron per carbon atom. Electron transmission through C70 molecule from the input to the output terminal is obtained. From the spectrum, the switching feature of the electron transmission through C70 is found, and the oscil-lation property based on the quantized level is explained. The quantum current distributions inside C70 molecule bridge are calculated and simulated by the quan-tum current density theory based on Fisher-Lee formula at the energy point E = -0.2.eV, where the transmission spectrum shows a peak. The maximum and the mini-mum bond quantum currents are presented, and the reason why the currents are distributed nonuniformly is explained by the phase difference of the atomic orbits. The result shows that the currents at each atomic site agree with Kirchhoff quan-tum current conservation law.

关键词： C70 molecule electron transmission quantum current distribution

Preparation and Property of Chromium Carbide Thermal Diffusion Coating on Cold Working Die Materials

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Journal of Wuhan University of Technology(Materials Science) 2010年第4期25卷 596-599页

作者：袁志华 School of Electrical and Mechanical Engineering North University of China School of Equipment Engineering Shenyang Ligong University

Thermal diffusion （TD） salt bath chromizing of cold working dies was studied. Firstly, it obtained an ideal salt bath formula by comparing with a variety of formulas, and then obtained the influence rule of coating thickness based on studying of some process parameters. The microstructure morphologies and phase structures of the TD chromizing coating were investigated by X-ray diffraction （XRD）, energy-dispersive spectrometry （EDS） and other modern analysis methods. Meanwhile, it carried out a system of testing and analysis of coating, such as hardness, wear resistance, etc.

关键词： chromium carbide coating thermal diffusion process cold working die preparation SEM EDS

用原位x射线小角散射研究块体非晶合金Zr_(55)Cu_(3.)Al_(10)Ni_5的结构弛豫

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物理学报 2003年第9期52卷 2219-2222页

作者：柳义柳林王俊赵辉荣利霞董宝中中国原子能科学研究院北京102413 华中科技大学材料学院武汉430074 中国科学院高能物理研究所同步辐射实验室北京100039

应用同步辐射x射线小角散射法在原位对块体非晶合金Zr55Cu3. Al1 0 Ni5在等温退火过程中的微结构变化进行研究 .实验表明 :在等温退火过程中电子密度涨落反映了晶化之前的结构弛豫过程 ;在一定的退火温度下、随退火时间的增加 ,拓扑短... 详细信息

应用同步辐射x射线小角散射法在原位对块体非晶合金Zr55Cu3. Al1 0 Ni5在等温退火过程中的微结构变化进行研究 .实验表明 :在等温退火过程中电子密度涨落反映了晶化之前的结构弛豫过程 ;在一定的退火温度下、随退火时间的增加 ,拓扑短程序弛豫与化学短程序弛豫之间存在一个电子密度均匀化的过程 ;导致这两种弛豫过程转变的退火时间与退火温度有关 ,温度越高。

关键词：原位x射线小角散射块体非晶合金等温退火结构弛豫 Zr55Cu3.Al10Ni5合金电子密度涨落

Theoretical study of ZnO adsorption and bonding on Al_2._3.0001) surface

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Science China(Physics,Mechanics & Astronomy) 2004年第6期47卷 664-675页

作者： LI Yanrong1,YANG Chun1,2.XUE Weidong1,LI Jinshan3.& LIU Yonghua3.1.{2. of Microelectronics and Solid State Electronics,University of Electronic Science and Technol- ogy of China,Chengdu 610054,China 2.{2. of Mathematics and Software Science,Sichuan Normal University,Chengdu 610068,China 3.{2. of Chemical Materials,China Academy of Engineering Physics,Mianyang 62.000,China institute of Microelectronics and Solid State Electronics University of Electronic Science and Technology of China Chengdu 610054 China institute of Mathematics and Software Science Sichuan Normal University Chengdu 610068 China institute of Chemical Materials China Academy of Engineering Physics Mianyang 621000 China

ZnO adsorption on sapphire (0001) surface is theoretically calculated by using a plane wave ultrasoft pseudo-potential method based on ab initio molecular dynamics. The results reveal that the surface relaxation in the first layer Al-O is reduced, even eliminated after the surface adsorption of ZnO, and the chemical bonding energy is 43..3.±3..6) kJ·mol?1. The chemical bond of ZnO (0.185 ± 0.01 nm) has a 3.° angle away from the adjacent Al-O bond, and the stable chemical adsorption position of the Zn is deflected from the surface O-hexagonal symmetry with an angle of about 3.°. The analysis of the atomic populations, density of state and bonding electronic density before and after the adsorption indicates that the chemical bond formed by the O2.of the ZnO ? and the surface Al3. has a strong ionic bonding characteristic, while the chemical bond formed by the Zn2. and the surface O2.has an obvious covalent characteristic, which ? comes mainly from the hybridization of the Zn 4s and the O 2. and partially from that of the Zn 3. and the O 2..

关键词： α-Al2.3.(0001) ZnO ab initio molecular dynamics chemical adsorption density of states

Full fermion-boson vertex function derived in terms of symmetry relations in Abelian gauge theory

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Science China(Physics,Mechanics & Astronomy) 2008年第9期51卷 1206-1213页

作者： HE HanXin China institute of atomic {2., Beijing {3. China China institute of atomic {2. Beijing 102413 China

Nonperturbative studies such as confinement and dynamical chiral symmetry breaking need the nonperturbative interacting vertex functions. In this paper, an approach to determining the full fermion-boson vertex function in four-dimensional Abelian gauge theory is presented: this full vertex function is derived in terms of a set of normal (longitudinal) and transverse Ward-Takahashi relations for the fer-mion-boson (vector) and axial-vector vertices in the momentum space in the case of massless fermion. Such a derived fermion-boson vertex function should be sat-isfied both perturbatively and nonperturbatively. The fact that such a derived full fermion-boson vertex function to one-loop order holds indeed is proven and the nonperturbative form of this vertex is also under discussion.

关键词： symmetry Ward-Takahashi relations full fermion-boson vertex function

Torque model of hydro turbine with inner energy loss characteristics

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Science China(Technological Sciences) 2010年第10期53卷 2826-2832页

作者： ZENG Yun1,2. GUO YaKun2. ZHANG LiXiang1, XU TianMao3.& DONG HongKui4 1 Construction Engineering College, Kunming University of Science and Technology, Kunming 650051, China 2.School of Engineering, University of Aberdeen, Aberdeen AB2. 3.E, UK 3.Computing Center, Kunming University of Science and Technology, Kunming 650051, China 4 Hydraulic energy Department, Yunnan Electric Power Test and Research institute, Kunming 6502.7, China 1. Construction Engineering College Kunming University of Science and Technology Kunming 650051 China2. School of Engineering University of Aberdeen Aberdeen AB24 3UE UK3. Computing Center Kunming University of Science and Technology Kunming 650051 China4. Hydraulic Energy Department Yunnan Electric Power Test and Research Institute Kunming 650217 China

This paper presents the result and analysis of the composition of energy loss occurring in the hydro turbine. Two new types of energy losses,namely the hydraulic loss in the flow channel and the impact loss,are defined. All losses within the hydro turbine are divided into four types and the loss coefficients are defined accordingly. Expressions or characteristic descriptions of these losses as well as the calibration method of the loss coefficients are presented. Furthermore,the torque model of the hydro turbine where the inner energy loss takes place is established. The developed model has been used to calculate the power loss due to the mechanical friction generated by the units’ rotation to solve the difficulty of measurements of the mechanical friction loss in the hydro turbine. The definition of the impact loss explains the phenomenon that the loss of no-load is greater than that of the rated operation. A set of conversion coefficients are defined using the characteristic parameters at the rated operation,which are used to transform the parameters in the torque model into those that are easily measured. Therefore,the expression of the hydro turbine power is converted into a function that has the main servomotor displacement as its single variable. This makes the proposed model be convenient to use. Finally,the proposed model and methods are calibrated and verified using the measured data of a hydropower plant. Good agreement between the modeled results and the measurements indicates that the proposed model can represent the inner energy loss characteristics of the hydro turbine.

关键词： hydraulic loss in flow channel impact loss loss coefficients conversion coefficients

Random Phase Approximation in Relativistic Approach

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原子核物理评论 2009年第S1期26卷 49-54页

作者： MA Zhong-yu1,2.YANG Ding1,TIAN Yuan1,CAO Li-gang2.3.1 China institute of {2. energy,Beijing {3.China 2.Center of Theoretical Nuclear Physics,National Laboratory of Heavy Ion Research Facility in Lanzhou,Lanzhou 73.000,China 3.institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 73.000,China) China institute of atomic {2. Beijing 102413China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Research Facility in LanzhouLanzhou 730000China China institute of atomic {2. Beijing 102413China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Research Facility in LanzhouLanzhou 730000China institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China

Some special issues of the random phase approximation(RPA) in the relativistic approach are reviewed. A full consistency and proper treatment of coupling to the continuum are responsible for the successful application of the RPA in the description of dynamical properties of finite nuclei. The fully consistent relativistic RPA(RRPA) requires that the relativistic mean filed (RMF) wave function of the nucleus and the RRPA correlations are calculated in a same effective Lagrangian and the consistent treatment of the Dirac sea of negative energy states. The proper treatment of the single particle continuum with scattering asymptotic conditions in the RMF and RRPA is discussed. The full continuum spectrum can be described by the single particle Green's function and the relativistic continuum RPA is established. A separable form of the paring force is introduced in the relativistic quasi-particle RPA.

关键词： fully consistent RRPA coupling to the continuum pairing correlation

Electronic structure of edge dislocation of core-doped Ti in Fe

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Progress in Natural Science:Materials International 2004年第6期 15-20页

作者： DANG Hongli 1 *,WANG Chongyu 1,2.3.and SHU Xiaolin 1(1. Central Iron and Steel Research institute,Beijing 100081,China 2. Department of Physics,Tsinghua University,Beijing 100084,China 3. International Center for Materials Physics,Academica,Shenyang 110016,China) Central Iron and Steel Research institute，Beijing 100081，China Central Iron and Steel Research institute，Beijing 100081，China Department of Physics，Tsinghua University，Beijing 100084 China International Center for Materials Physics，Academica，Shenyang 110016，China

The electronic structure of an edge dislocation doped Ti lying in the (001) plane with Burgers Vector along [100] direction in body-centered cubic iron is investigated using the first principles discrete variational method (DVM) based on the density-functional theory. The binding energy,impurity formation energy,inter{2. energy,Mulliken orbital populations and charge density difference are presented in this paper. By calculating the binding energy of the clean dislocation system and the Ti-doped system,it is found that the binding energy of Ti-doped dislocation system is lower than that of the clean dislocation system,which implies that the Ti-doped dislocation system is more stable than the clean dislocation system. The calculated result of the impurity formation energy predicts the trapping effect of dislocation core for Ti,which shows that Ti atom prefers to occupy the place at the dislocation core. The calculated results of the inter{2. energy and the difference charge density of dislocation doped Ti system indicate that the stronger bonding formed between the Ti impurity and its neighbor Fe atoms will affect the mechanical property of edge dislocation. Considering the influence of Ti on the electronic structure and the energies,we can predict that the trace Ti in transition metal Fe with dislocation defect can give a significant contribution to the solid solution hardening effects and will influence the mechanical property of materials.

关键词： edge dislocation doping effect electronic structure.

Molecular dynamics simulations on the structures and properties of ε-CL-2.-based PBXs ——Primary theoretical studies on HEDM formulation design

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Science China Chemistry 2007年第6期50卷 737-745页

作者： XU XiaoJuan1,2. XIAO JiJun1, HUANG Hui3. LI JinShan3.& XIAO HeMing1 1 Department of Chemistry, Nanjing University of Science and Technology, Nanjing 2.0094, China 2.Department of Chemistry, Yancheng Teacher’s College, Yancheng 2.4002. China 3.institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 62.900, China Department of Chemistry Nanjing University of Science and TechnologyNanjing 210094China Department of Chemistry Yancheng Teacher''s CollegeYancheng 224002China institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900

Five polymer bonded explosives(PBXs)with the base explosive epsilon-CL-2.(hexanitrohexaazaisowurtzi-tane),the most important high energy density compound(HEDC),and five polymer binders(Estane 5703.GAP,HTPB,PEG,and F_(2.1}4))were *** dynamics(MD)method was employed to investigate their binding energies(E_(bind))energy density material(HEDM).According to the calculated binding energies,the ordering of compatibility and stability of the five PBXs was predicted as epsilon-CL-2./PEG 2./ Estane5703.≈ epsilon-CL-2./GAP 2./HTPB 2./F_(2.1}4).By pair correlation function g(r)analyses,hydrogen bonds and vdw are found to be the main interactions between the two *** elasticity and isotropy of PBXs based epsilon-CL-2. can be obviously improved more than pure epsilon-CL-2. *** is not by changing the molecular structures of epsilon-CL-2. for each binder to affect the *** safety and energetic properties of these PBXs are mainly influenced by the thermal capability(C_p^(deg))and density(p)of binders,respectively.

关键词： high energy density material (HEDM), hexanitrohexaazaisowurtzitane (CL-2.), polymer bonded explosives (PBXs), molecular dynamics (MD), compatibility, safety properties, mechanical properties, energetic properties