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A STUDY OF OSCILLATING FLOWS OVER PROPAGATING RIPPLES:PART Ⅱ. VORTICITY DYNAMICS

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Journal of Hydrodynamics 2000年第1期12卷 8-15页

作者： Lu Xi yun department of modern Mechanics, university of Science and Technology of china, Hefei 230026, P.R.china Univ of Science and Technology of China Hefei China

Vortex shedding for an oscillating flow over ripples is numerically investigated by solving 2 D time dependent incompressible Navier Stokes equations in curvilinear coordinates. The dynamics of vortex structures generated by flow separation is studied in order to understand some phenomena which take place near the bottom and in particular to get insight into the mechanism through which sediment grains are lifted up and maintained in suspension. Based on our calculated results, some important phenomena, such as vortex shedding, vortices pairing, vortices coalescence, vortex interaction with the free shear layer and so on, can be found. The behaviors of energy dissipation in the flow field and of shear stress along the ripple surface are also discussed for studying the dynamics of sediment grains in suspension and to obtain new information on the suspended load over the ripples.

关键词： oscillating flow ripple vorticity dynamics separation flow

A study of two-dimensional magnetic polaron

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Science china(physics,Mechanics & Astronomy) 2006年第4期49卷 421-429页

作者： LIU Tao1, ZHANG Huaihong1, FENG Mang1,2 & WANG Kelin1,3 1. School of Science, Southwest university of Science and Technology, Mianyang 621010, china 2. Wuhan Institute of physics and Mathematics, Chinese Academy of Sciences, Wuhan 430070, china 3. department of modern physics, university of Science and Technology of china, Hefei 230026, china School of Science Southwest University of Science and Technology Mianyang 621010 China

By using the variational method and anneal simulation, we study in this paper the self-trapped magnetic polaron (STMP) in two-dimensional anti-ferromagnetic material and the bound magnetic polaron (BMP) in ferromagnetic material. Schwinger angular momentum theory is applied to changing the problem into a coupling problem of carriers and two types of Bosons. Our calculation shows that there are single-peak and multi-peak structures in the two-dimensional STMP. For the ferromagnetic material, the properties of the two-dimensional BMP are almost the same as that in one-dimensional case; but for the anti-ferromagnetic material, the two-dimensional STMP structure is much richer than the one-dimensional case.

关键词： self-trapped magnetic polaron, bound magnetic polaron, impurity potential, anti-ferromagnet.

The Effect of SRS on Signal Power in Single mode Silica Fiber in DWDM Optical Communication System with Equally Spaced Channels

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Chinese Journal of Lasers 2000年第1期9卷 52-57页

作者： GONG Jiamin 1 FANG Qiang 2 LIU Juan 2 WANG Yongchang 1 ( 1Institute of modern physics, Xi'an JiaoTong university, Xi'an 710049,china 2department of Telecommunications, Xi'an Institute of Posts and Telecommunications, Xi'an 710061, C 西安交通大学陕西西安西安邮电学院陕西西安

Assuming that the Raman gain profile of silica fiber is a triangular function, we derive analytic solutions of N channel  steady state forward SRS coupling wave equation with equal (but arbitrary) channel spacing. Considering the SRS cross coupling among N channels,  the analytic solutions are applicable to arbitrary signal light power. The results point out that the sequence m i=p i(z)/p i(0) 〔p i(z) and p i(0) is the power of signal light of i th  channel at transmission length z and 0, respectively. i=1,2,…N〕 maintains a geometric progression with the common ratio q in the transmission process. The common ratio q varies as a exponential function of the effective transmission length, the sum of input light power and the channel spacing, respectively.

关键词： stimulated Raman scattering (SRS) density wavelength division multiplexing fused silica fiber

Point spread functions for a small gamma camera with pinhole collimator

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Nuclear Science and Techniques 2003年第3期14卷 195-198页

作者： LIU Shi-Tao, XU Zi-Zong, WANG Zhao-Min, XU Shen-Bo (department of modern physics, university of Science and Technology of china, Hefei 230027) department of modern physics University of Science and Technology of China Hefei 230027

A set of point spread functions (PSF) has been obtained by means of Monte-Carlo simulation for asmall gamma camera with a pinhole collimator of various hole diameters. The FOV (field of view) of the camera isexpended from 45 mm to 70 mm in diameter. The position dependence of the variances of PSF is presented, and theacceptance for the 140 kev gamma rays is explored. A phantom of 70 mm in diameter was experimentally imaged inthe camera with effective FOV of only 45 mm in diameter.

关键词：点扩散函数 γ照相机针孔准直器 PSF Monte-Carlo仿真临床诊断

Accurate studies on the full vibrational energy spectra and molecular dissociation energies for some electronic states of N_(2)molecule

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Science china(physics,Mechanics & Astronomy) 2005年第4期48卷 385-398页

作者： REN Weiyi1,2, SUN Weiguo1, HOU Shilin3 & FENG Hao4 1. Institute of physics, College of Chemical Engineering, Sichuan university, Chengdu 610065, china 2. Institute of Theoretical physics, Xihua Normal university, Nanchong 637002, china 3. department of physics, china Oceanography university, Qingdao 266003, china 4. College of physics, Sichuan university, Chengdu 610065, china Institute of physics College of Chemical Engineering Sichuan University Chengdu China Institute of Theoretical physics Xihua Normal University Nanchong China department of physics China Oceanography University Qingdao China College of physics Sichuan University Chengdu China

It is usually very difficult to directly obtain molecular dissociation energy De and all accurate high-lying vibrational energies for most diatomic electronic states using modern experimental techniques or quantum theories, and it is also very difficult to give accurate analytical expression for diatomic molecular dissociation energy. This study proposes a new analytical formula for obtaining accurate molecular dissociation energy based on the LeRoy and Bernstein’s energy expression in dissociation limit. A set of full vibrational energy spectra for some electronic states of N2 molecule are studied using the algebraic method (AM) suggested recently, and the corresponding accurate molecular dissociation energies are evaluated using the proposed new formula and high-lying AM vibrational energies. The results show that the AM spectra and the new theoretical dissociation energies agree excellently with experimental data, and thereby providing a new physical approach to generating accurate dissociation energies for electronic states of diatomic molecules.

关键词： vibrational energy, dissociation energy, nitrogen molecule, algebraic method.

Simulation study of real-time monitor for BEPC-Ⅱ luminosity

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Science china(Technological Sciences) 2010年第5期53卷 1215-1219页

作者： SHAN Qing1,2,WU Jian2,XUE Zhen2,XU ZiZong2,HU Tao3,WANG YiFang3 & WANG XiaoLian2 1 College of Material Science and Technology,Nanjing university of Aeronautics and Astronautics,Nanjing 210016,china 2 department of modern physics,university of Science and Technology of china,Hefei 230026,china 3 Institute of High Energy physics,Chinese Academy of Sciences,Beijing 100049,china College of Material Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing China department of modern physics University of Science and Technology of China Hefei China Institute of High Energy physics Chinese Academy of Sciences Beijing China

A fast and real time luminosity monitor system will be used in the BEPC-Ⅱ(Beijing Electron Positron Collider,china).Photons generated in radiative Bhabha scattering at the interaction point are transformed into charged particles,and then the luminosity of each bunch pair is measured through collecting the Cherenkov light produced by charged particles in fused *** whole process happening in the detector is *** physics acceptance and detection threshold with the monitor accu-racy of 1% are set based on the simulation spectra of photoelectron yield calibrated by e-beam data.

关键词： luminosity BEPC-Ⅱ Cherenkov detector radiative Bhabha

Solutions of Non-Autonomous Quantum Systems with Symplectic Algebraic Structure

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Solutions of Non-Autonomous Quantum Systems with Symplectic ...

Status of Theoretical Study on Superheavy Nuclei

中国数学力学物理学高新技术交叉研究会第9届学术研讨会

作者： Jie Quanlin~1 Wang Shunjin~(1,2,3) (1.Institute of modern physics,Southwest Jiaotong university Chengdu 610031 china 2.department of modem physics,lanzhou university lanzhou 730000 china 3.Center of Theoretical physics,CCAST(World Laboratory)Beijing china.)

＜正＞Based on the structure of sub-algebraic chain of sp（2N）Lie algebra,we obtain solutions of a non-autonomous quantum system with Hamiltonian that can be treated as a linear function of generators of an sp（2N）symplectic *** Hamiltonian is transformed into a function of commutable Cartan operators by a set of gauge *** solutions of the equations of motion are obtained from the inverse gauge transformations. An sp（4）model describing a charged particle in a Paul trap interacting with a single mode of electromagnetic field serves as an illustration.

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Status of Theoretical Study on Superheavy Nuclei

X-ray Spectra Induced by 40Ar17+ Interacting with Au Surface

CCAST“放射性束物理”研讨会

作者： Zhongzhou Ren(1) department of physics, Nanjing university, Nanjing 210008, P. R. china (2) Center of Theoretical Nuclear physics, Institute of modern physics, lanzhou 730000, P. R.china

＜正＞At first I will briefly review the new experimental progress of superheavy *** I willtalk about theoretical studies on superheavy *** is mainly on the structure of *** upper limit and a lower limit for the binding energy of superheavy nuclei areestablished based on the relativistic mean-field *** is useful for future calculationsof the cross-section to synthesize a new superheavy *** is also helpful to *** of alpha decay for a unknown superheavy *** some suggestions areproposed in order to speed up the progress of study on superheavy nuclei in china.

关键词： superheavy elements alpha-decay energies lifetimes name of future new element: Chinium (Cn).

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IMP & HIRFL Annual Report 2005年 120-121页

作者： Zhang Xiaoan, Xiao Guoqing, Zhao Yongtao, Yang Zhihu and Chen Ximeng department of physics, Xianyang Normal university, Xianyang. department of modern physics, lanzhou university, lanzhou.

When a highly charged ion with many inner shell holes is approaching to a metallic surface, the conducting -band electrons in the metal can resonantly transfer into the high orbits of the projectile at a large distance. In this way, the ion could be temporarily neutralized to form a hollow atom with outer shell occupied and inner shells empty. The hollow atoms may de-excite by auto ionization, Auger electron emission and cascade radioactive X-rays. At the very moment when the projectile reaching the surface, its outer shell electrons will be partly peeled off, however the holes in the inner-most shell could still survive for a

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