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Radiative lifetimes of Rydberg states of BeⅠand BeⅢ

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原子与分子物理学报 2003年第4期20卷 575-578页

作者： LIANG Liang~(1,2., WANG Yong-chang~1 (1. Institute of modern physics, School of science, Xi’an Jiaotong university, Xi’an 710049, P. R. China 2.{2., Xi’an university of Architecture and Technology, Xi’an 710055, P. R. China) Institute of moderm physics School of scienceXi'an Jiaotong University Xi'an 710049

By using the multichannel quantum defect theory （MQDT）, we have evaluated the energy levels and lifetimes of 2.ns （）3S1,2.nd（）3D（n=3-2.） of BeⅠ and 1sns（）3S1,1snd （）3D（n=3-2.） of BeⅢ. These energies and lifetimes that we have calculated not only agree with the recent measurements and theoretical calculation of Ref.4 and Ref.3, but also predict the lifetimes of 66 other highly excited states.

关键词：辐射寿命里德伯态多道量子缺陷理论铍元素原子高激发态原子物理学

A novel endorectal RF coil for high resolution MRI and spectroscopy of the prostate

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Progress in Natural Science:Materials International 2005年第5期15卷 472-476页

作者： ZHANG Hongjie 1,2. SONG Xiaoyu1, WANG Xiaoying3, XU Pingfang1 and BAO Shanglian1*(1. Beijing Key Laboratory of Medical physics & Engineering, peking university, Beijing 100871, China 2. Navy General Hospital, Beijing 100037, China 3. peking university First Hospital, Beijing 100034, China) Beijing Key Laboratory of Medical physics & Engineering Peking University Beijing 100871 China Navy General Hospital Beijing 100037 China peking university First Hospital Beijing 100034 China

The diagnosis of prostate diseases by magnetic resonance imaging (MRI) in vivo is sometimes difficult for the lower signal to noise ratio (SNR). To increase the SNR of the prostate image, we designed a RF coil that can be inserted into rectum and was named endorectal coil. The properties of RF coil were evaluated using a network analyzer. Moreover the images and spectroscopy of a special phantom were acquired and the results were compared to those of the commercial TORSO coil (G.E. Medical Systems, USA). Our coil gave a significantly higher SNR at the region of interest (ROI). The achieved high local SNR and resulting high spatial resolution would add more anatomic and biochemical information to the diagnosis of prostate diseases.

关键词： MRI RF coil endorectal coil.

Global analysis theory of climate system and its applications

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Chinese Science Bulletin 2003年第10期48卷 1034-1039页

作者： LI Jianping1,2.& CHOU Jifan2.3 1. LASG, Institute of Atmospheric physics, Chinese Academy of Sciences, Beijing 10002., China 2. department of Atmospheric Sciences, Lanzhou {2., Lanzhou 730000, China 3. Training center for China Meteorological Administration, Beijing 100081, China department of Atmospheric Sciences Lanzhou University Lanzhou 730000 China LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The idea and main theoretical results of the global analysis theory of climate system are briefly summarized in this paper. A theorem on the global behavior of climate system is given, i.e. there exists a global attractor in the dynamical equations of climate, any state of climate system will be evolved into the global attractor as time increases, indicating the nonlinear adjustment process of climate system to external forcing. The different effects of external forcing, dissipation and nonlinearity on the long-term behavior of solutions are pointed out, and some main applications of the global analysis theory are also introduced. Especially, three applications, the adjustment and evolution processes of climate, the principle of numerical model design and the optimally numerical integration, are discussed.

关键词：整体分析理论气侯体系应用不定性计算法则气侯科学数字模型

B→K~*γ Decay in Top-Quark Two-Higgs-Doublet Model

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Communications in theoretical physics 2006年第11期46卷 895-900页

作者： XIAO Zhen-Jun,~+ CHENG Hui-Hui, and L Lin-Xia department of physics and Institute of theoretical {2., Nanjing Normal university, Nanjing 2.0097, China department of physics Nanjing Normal University Institute of theoretical physics Nanjing Normal University

By employing the QCD factorization approach for the exclusive B→Vγ decays, we study the exclusive decay B→K~*γ in the top-quark two-Higgs-doublet model (T2.DM). Within the considered parameter space, we find the following conclusions (a) A light charged-Higgs boson with a mass about 2.0 GeV is clearly excluded by the date of B→K~*γ decay, and this lower limit is comparable with that from the inclusive B→Xγ decay; (b) The theoretical predictions for CP asymmetry of B→K~*γ in the T2.DM is always less than 1% in size; and (c) The isospin symmetry breaking for B→K~*γ decay in the SM and T2.DM considered here is around 6% in size and well consistent with the data and the general expectations.

关键词： B meson decay charged-Higgs boson branching ratio CP asymmetry

Magnetic moments of ^(33)Mg in the time-odd relativistic mean field approach

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Science China(physics,Mechanics & Astronomy) 2009年第10期52卷 1586-1592页

作者： LI Jian1,ZHANG Ying1,YAO JiangMing1 & MENG Jie1,2.1 School of physics,State Key Laboratory of Nuclear physics and Technology,{2. university,Beijing 100871,China 2.School of physics and Nuclear Energy Engineering,Beihang university,Beijing 100191,China School of physics State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China School of physics and Nuclear Energy Engineering Beihang University Beijing 100191 China

The configuration-fixed deformation constrained relativistic mean field approach with time-odd component has been applied to investigate the ground state properties of 33Mg with effective interaction *** ground state of 33Mg has been found to be prolate deformed,β2.0.2.,with the odd neutron in 1/2.330] orbital and the energy -2.1.85 MeV which is close to the data -2.2.06 *** magnetic moment -0.9134 μN is obtained with the effective electromagnetic current which well reproduces the data -0.7456 μN self-consistently without introducing any *** energy splittings of time reversal conjugate states,the neutron current,the energy contribution from the nuclear magnetic potential,and the effect of core polarization are discussed in detail.

关键词： magnetic moment binding energy time-odd component configuration-fixed deformation constrained calculation relativistic mean field theory

B→Xsγ, Xsl+l~-Decays and Constraints on Mass Insertion Parameters in MSSM

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Communications in theoretical physics 2006年第10期46卷 687-696页

作者： XIAO Zhen-Jun,~+ LI Feng-Ying, and ZOU Wen-Jun department of physics and Institute of theoretical {2., Nanjing Normal university, Nanjing 2.0097, China department of physics Nanjing Normal University Institute of theoretical physics Nanjing Normal University

In this paper, we study the upper bounds on the mass insertion parameters (δ~q)in the minimal supersymmetric standard model. We found that the information from the measured branching ratio of B→Xl+l~-decaycan help us to improve the upper bounds on the mass insertions parameters(δ. Some regions allowed by thedata of Br(B→Xγ)are excluded by the requirement of an SM-like C(m)imposed by the data of Br(B→Xl+l~-).

关键词： B meson decay the minimal supersymmetric standard model mass insertion

Debating about the climate warming

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Progress in Natural Science:Materials International 2006年第1期16卷 1-6页

作者： WANG Shaowu1, LUO Yong2. ZHAO Zongci2. DONG Wenje2.and YANG Bao3 (1.department of Atmospheric Sciences, School of physics,{2., Beijing 100871, China 2. Laboratory for Climate Studies, China Meteorological Administration, Beijing 100081, China 3. Institute of Cold and Arid Regions Environmental and Engineering, Chinese Academy of Sciences, Lanzhou 730000, China) [a] department of Atmospheric Sciences School of Physics Peking University Beijing China [b] Laboratory for Climate Studies China Meterological Administration Beijing China [c] Institute of Cold and Arid Regions Environmental and Engineering Chinese Academy of Sciences Lanzhou China

Debating about the climate warming is reviewed. Discussions have focused on the validity of the temperature reconstruction for the last millennium made by Mann et al. Arguments against and for the reconstruction are introduced. Temperature reconstructions by other authors are examined, including the one carried out by Wang et al. in 1996. It is concluded that: (1) Ability of reproducing temperature variability of time scale less than 10 a is limited, so no sufficient evidence proves that the 1990s was the warmest decade, and 1998 was the warmest year over the last millennium. (2. All of the temperature reconstructions by different authors demonstrate the occurrence of the MWP (Medieval Warm Period) and LIA (Little Ice Age) in low frequency band of temperature variations, though the peak in the MWP and trough in LIA varies from one reconstruction to the others. Therefore, terms of MWP and LIA can be used in studies of climate change. (3) The warming from 1975 to 2.00 was significant, but we do not know if it was the strongest for the last millennium, which needs to be proved by more evidence.

关键词： climate warming MWP LIA the 2.th century.

Simulation of nuclei morphologies for binary alloy

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Science China Mathematics 2010年第11期53卷 2927-2936页

作者： LI DaMing1, & ZHANG PingWen2.1department of Mathematics, Shanghai Jiaotong university, Shanghai 2.02.0, China 2.ey Lab of Mathematics and Applied Mathematics, {2. for Applied physics and Technology and School of Mathematical Sciences, peking university, Beijing 100871, China 1. department of Mathematics Shanghai Jiaotong University Shanghai 200240 China2. Key Lab of Mathematics and Applied Mathematics Center for Applied Physics and Technology and School of Mathematical Sciences Peking University Beijing 100871 China

We study the critical nuclei morphologies of a binary alloy by the string method. The dynamic equation of the string, connecting the metastable phase (liquid) and stable phase (solid), is governed by Helmholtz free energy for the binary alloy system at a given temperature. The stationary string through the critical nucleus (saddle point) is obtained if the relaxation time of the string is su?ciently large. The critical nucleus radius and energy barrier to nucleation of a pure alloy with isotropic interface energy in two and three dimensions are calculated, which are consistent with the classical nucleation theory. The critical nuclei morphologies are sensitive to the anisotropy strength of interface energy and interface thickness of alloy in two and three dimensions. The critical nucleus and energy barrier to nucleation become smaller if the anisotropy strength of the interface energy is increased, which means that it is much easier to form a stable nucleus if the anisotropy of the interface energy is considered.

关键词： nucleation crystal morphology string method

A computational investigation of boron-doped chromium and chromium clusters by density functional theory

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Science China(physics,Mechanics & Astronomy) 2010年第5期53卷 812-817页

作者： GE GuiXian1,JING Qun1 & LUO YouHua2.3 1 Key Laboratory of Ecophysics and department of physics,Normal College,Shihezi {2.,Xinjiang 832.03,China 2.School of Science,East China {2. of Science and Technology,Shanghai 2.02.7,China 3 Institute of theoretical physics,School of physics and Information Optoelectronics,Henan {2.,Kaifeng 475004,China 1. Key Laboratory of Ecophysics and department of physics Normal College Shihezi University Xinjiang 832003 China2. School of Science East China University of Science and Technology Shanghai 200237 China3. Institute of Theoretical Physics School of Physics and Information Optoelectronics Henan University Kaifeng 475004 China

The geometries,stabilities and electronic properties of Crn and CrnB(n=2.9) clusters have been systematically investigated by density functional *** results suggest that the lowest energy structures for CrnB clusters can be obtained by substituting one Cr atom in Crn+1 clusters with B *** geometries of CrnB clusters are similar to that of Crn+1 clusters except for local structural *** second-order difference and fragmentation energy show Cr4,Cr6,Cr8,Cr3B,Cr5B and Cr8B cluster are the most stable among these studied *** impurity B increases the stabilities of chromium *** B is doped on the Crn clusters,cluster geometry does dominate positive role in enhancing their *** doped B atom does not change the coupling way of the Cr site in Crn clusters,but breaks the symmetry and the Cr atoms are no longer *** doped B atom increases the total magnetic moments of Crn in most cases.

关键词： Crn and CrnB clusters geometries electronic properties