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Single crystal β-Ga_2._3: Cr grown by floating zone technique and its optical properties

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Science China(Technological sciences) 2007年第1期50卷 51-56页

作者： ZHANG JunGang1, 2. LI Bin3, XIA ChangTai1, XU Jun1, DENG Qun4, XU XiaoDong1, WU Feng1, XU WuSheng4, SHI HongSheng4, PEI GuangQing1, 2.& WU YongQing1,2.1 Shanghai institute of Optics and Fine Mechanics, chinese academy of sciences, Shanghai 2.1800, China 2.Graduate School of the chinese academy of sciences, beijing 100039, China 3 Shanghai institute of Applied physics, chinese academy of sciences, Shanghai 2.1800, China 4 GE (China) Research and Development Center Co. Ltd., Shanghai 2.12.3, China 1. Shanghai institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China 2. Graduate School of the chinese academy of sciences Beijing 100039 China 3. Shanghai institute of Applied physics Chinese Academy of Sciences Shanghai 201800 China 4. GE (China) Research and Development Center Co. Ltd. Shanghai 201203 China

β-Ga2.3: Cr single crystals were grown by floating zone technique. Absorption spectra and fluorescence spectra were measured at room temperature. The values of field splitting parameter Dq and Racah parameter B were obtained by the peak values of absorption spectra. The value 10Dq/B=2..14 manifests that in β-Ga2.3 crystals Cr3+ ions are influenced by low energy crystal field. After high temperature annealing in air, the Cr3+ intrinsic emission was enhanced and the green lumines-cence disappeared. The strong and broad 691 nm emission was obtained at 42. nm excitation due to the electron transition occurred from 4T2.to 4A2. The studies manifest that the β-Ga2.3 crystals have the potential application for tunable laser.

关键词： β-Ga2.3: Cr single crystals floating zone technique tunable laser spectrum.

Light collection of the POLAR detector

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Science China(physics,Mechanics & Astronomy) 2010年第S1期53卷 43-46页

作者： DONG YongWei,LI YanGuo,WU BoBing,ZHANG YongJie & ZHANG ShuangNan Key laboratory of Particle Astrophysics,{2. of High energy physics,chinese academy of sciences,beijing 100049,China 1. Key laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

POLAR is a compact polarimeter dedicated to measuring the polarization of GRBs between 50-350 *** light collection of 2.0 mm×6 mm×6 mm plastic bars has been simulated and optimized in order to get uniform response to X-rays at different points along one single *** to the Monte Carlo results,the amplitude uniformity strongly depends on the level of polishing of the scintillator surface and the covering.A uniformity of 89% is achieved with a prototype constructed by a non position-sensitive PMT and an array of 4×4 bars.

关键词： plastic scintillator light collection gamma-ray burst polarimeter

Collision dynamics of He@C_(60)+He@C_(60) at low energies

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Science China(physics,Mechanics & Astronomy) 2008年第7期51卷 765-772页

作者： ZHAO Qiang1,2. ZHANG FengShou1,2.3 & ZHOU HongYu1,2.1 Key laboratory of Beam Technology and Material Modification of Ministry of Education, institute of Low {2. Nuclear physics, beijing Normal University, beijing 100875, China 2.beijing Radiation Center, beijing 100875, China 3 Center of Theoretical Nuclear physics, National laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000, China 1. Key laboratory of Beam Technology and Material Modification of Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing 100875 China 2. beijing Radiation Center Beijing 100875 China 3. Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China

A semi-empirical molecular dynamics model is developed. The central collisions of C60+C60 and He@C60+He@C60 at different incident energies are investigated based on this model. It is found that the dimer structures have been produced at proper incident energies and these fullerene dimers could be formed by a self-assembly of C60 fullerene and He@C60. The He atom has a significant effect at higher incident energy and this embedded He atom can enhance the stability of the dimer structure.

关键词： C60 He@C60 collision molecular dynamics

SVOM gamma ray monitor

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Science China(physics,Mechanics & Astronomy) 2010年第S1期53卷 40-42页

作者： DONG YongWei,WU BoBing,LI YanGuo,ZHANG YongJie & ZHANG ShuangNan Key laboratory of Particle Astrophysics,{2. of High energy physics,chinese academy of sciences,beijing 100049,China 1. Key laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

The space-based multi-band astronomical Variable Object Monitor(SVOM) mission is dedicated to the detection,localization and broad-band study of gamma-ray bursts(GRBs) and other high-energy transient *** gamma ray monitor(GRM) onboard is designed to observe GRBs up to 5 *** this instrument,one of the key GRB parameters,Epeak,can be easily measured in the hard X-ray *** can achieve a detection rate of 100 GRBs per year which ensures the scientific output of SVOM.

关键词： gamma-ray burst Epeak triple phoswich

X（3872. and Bound State Problem of D0*0（0 D*0）

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原子核物理评论 2009年第S1期 16-21页

作者： LIU Yan-rui1,LIU Xiang2.3,DENG Wei-zhen2.(1 institute of High energy {2.,chinese academy of sciences,beijing 100049,China 2.Department of {2.,Peking University,beijing 100871,China 3 Centro de Física Terica,Departamento de Física,Universidade de Coimbra,P-3004-516,Coimbra,Portugal)

We have performed a dynamical calculation of the bound state problem of D0D*0 by considering the pion and sigma meson exchange potential. Our preliminary analysis disfavors the molecular interpretation of X(3872. if we use the experimental D*Dπ coupling constant g=0.59 and a reasonable cutoff around 1 GeV,which is the typical hadronic scale. In contrast,there probably exists a loosely bound S-wave BB* molecular state. Such a molecular state would be rather stable since its dominant decay mode is the radiative decay through B*→Bγ.

关键词： X(3872. bound state molecule

UNDERSTANDING FOR THE KONDO INSULATOR

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低温物理学报 1993年第6期 415-418页

作者： Wang YupengCCAST (World laboratory) Cryogenic laboratory,{2., beijing 100080Jin DuoCryogenic laboratory,{2., beijing 100080

A theoretical concerning about the Kondo insulator is proposed in the half filled valence fluctuation model. It is shown that the energy band may be splitted into three subband, i.e. the bonding-band, antibonding-band and non-bonding band. For strong enough hybridization, the system will show semiconductor behavior at low temperatures. This behavior can be also understood in the Hubbard-Mott picture.

关键词： UNDERSTANDING FOR THE KONDO INSULATOR

In situ study on dendrite growth of metallic alloy by a synchrotron radiation imaging technology

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Science China(Technological sciences) 2010年第5期53卷 1278-1284页

作者： WANG TongMin1,XU JingJing1,LI Jun1,HUANG WanXia2.LIU ShengChu1 & LI TingJu1 1 School of Materials Science and Engineering,Dalian University of Technology,Dalian 11602.,China 2.institute of High energy {2.,chinese academy of sciences,beijing 100039,China 1. School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China2. Institute of High Energy Physics Chinese Academy of Sciences Beijing 100039 China

This study was trying to observe the real-time dendrite growth of Sn-Bi and Sn-Pb binary alloys by a synchrotron radiation imaging *** imaging system includes an intense and high brightness synchrotron radiation source,a high-resolution and fast-readout charge coupled device camera,an alloy sample and a Bridgman solidification *** imaging experiments were done at beijing Synchrotron Radiation Facility with an updated synchrotron radiation imaging technique,diffraction-enhanced imaging,which was firstly used to study the dendrite growth of metallic alloy.A series of growth behavior and morphology evolution of dendrite have been in situ observed,such as columnar-to-equiaxed transition,dendrite competition,dendrite fragmentation and floating,etc.,which can offer the direct proofs to verify or improve the solidification theories of metallic *** research opens a novel window for the study of alloy solidification and enables the unambiguous understanding of solidification processes in optically opaque,metallic alloys.

关键词： dendritic growth synchrotron radiation solidification diffraction-enhanced imaging metal and alloys

SYMPLECTIC COMPUTATION OF HAMILTONIAN SYSTEMS (I)

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Journal of Computational Mathematics 2002年第3期20卷 267-276页

作者： Yi-fa Tang(LSEC,ICMSEC,academy of Mathematics and System sciences,{2.,beijing 100080, China) 中科院数学与系统科学院 LSEC ICMSEC CAS 北京 100080

Presents information on a study which discussed a symplectic computation of hamiltonian systems. Terms of formal energy of mid-point rule; Analysis of the mathematical pendulum to test the convergence of the formal en... 详细信息

关键词： mid-point rule formal energy

Progress in multi-waveband observations of supernova remnants

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Progress in Natural Science:Materials International 2008年第9期18卷 1057-1062页

作者： Xuejuan Yang a,b, Fangjun Lua, Wenwu Tian c,d,* a Particle Astrophysics Center, institute of High {2. physics, chinese academy of sciences, beijing 100049, China b Department of Astronomy, beijing Normal University, beijing 100875, China c National Astronomical Observatories, chinese academy of sciences, 2.A Datun Road, Chaoyang District, CAS, beijing 100012. China d Department of physics & Astronomy, University of Calgary, Alberta, Canada T2. 1N4 Particle Astrophysics Center Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Department of Astronomy Beijing Normal University Beijing 100875 China National Astronomical Observatories Chinese Academy of Sciences 20A Datun Road Chaoyang District CAS Beijing 100012 China Department of physics & Astronomy University of Calgary Alberta Canada T2N 1N4

The development of observational techniques has enriched our knowledge of supernova remnants. In this paper, we review the main progresses in the last decade, including new discoveries of supernova remnants and the associated (rare type of) pulsars, nucleosynthesis, the interaction between supernova remnants and molecular clouds, dust in the supernova remnants, shock physics, and cosmic ray accelerations.

关键词： Supernova remnant Observations