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Structural phase transition in nanostructured γ-Fe_2._3

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Chinese Science Bulletin 1997年第11期42卷 894-897页

作者： YE Xisheng, SHA Jian, SONG Hongqin, JIAO Zhengkuan, LU Guanglie, PENG Zifei and ZHANG Lide1. department of physics, Zhejiang University, Hangzhou 31002., China 2. Central Laboratory, Hangzhou University, Hangzhou 31002., China 3. Institute of Solid State physics, Chinese Academy of Sciences, Hefei 2.0031, China department of physics Zhejiang IJniversity Hangzhou China Central laboratory Hangzhou University Harigzhou China Institute of Solid State physics Chinese Academy of Sciences Hefei China

DUE to their specific physical,chemical and mechanical properties and large application proba-bility in many fields,nanostructured materials have been developing very fast in the recent *** stability is an important property of the *** interesting resultshave been obtained in the study of the thermal stability of nanostructured materials.

关键词： nanostructured γ-Fe2.3 differential thermal analysis (DTA) XRD microstructlire structural phase transition.

Lepton flavor violating Z-boson decays at GigaZ as a probe of supersymmetry

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Science China(physics,Mechanics & Astronomy) 2010年第11期53卷 1949-1952页

作者： YANG JinMin 1,2.1 department of physics,Henan Normal University,Xinxiang 453007,China 2.Institute of Theoretical physics,Chinese Academy of Sciences,Beijing 100190,China 1. department of physics Henan Normal University Xinxiang 453007 China2. Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China

This paper briefly reviews the lepton flavor violating Z-decays at GigaZ as a probe of supersymmetry by focusing on Z → i j in two representative supersymmetric models: the minimal supersymmetric model without R-parity and the supersymmetric seesaw *** work concludes that under the current experimental constraints from LEP and i → j γ,these rare decays can still be enhanced to reach the sensitivity of the ***,supersymmetry can be probed via these decays at GigaZ.

关键词： Z-decay GigaZ supersymmetry

GRB 09042.:Marking the death of a massive star at z=8.2

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Science China(physics,Mechanics & Astronomy) 2010年第S1期53卷 64-68页

作者： LIN Lin1,LIANG EnWei2.& ZHANG ShuangNan3 1 department of physics and Center for Astrophysics,Tsinghua University,Beijing 100084,China 2.department of physics,Guangxi University,Nanning 530004,China 3 Key Laboratory of Particle Astrophysics,Institute of High Energy physics,Chinese Academy of Sciences,Beijing 100049,China Guangxi Univ Dept Phys Nanning 530004 Peoples R China Tsinghua Univ Dept Phys Beijing 100084 Peoples R China Tsinghua Univ Ctr Astrophys Beijing 100084 Peoples R China Chinese Acad Sci Inst High Energy Phys Key Lab Particle Astrophys Beijing 100049 Peoples R China

GRB 09042. is the new high-z record holder of Gamma-ray bursts(GRBs) with *** present a detailed analysis of both the spectral and temporal features of GRB 09042. observed with Swift/BAT and Fermi/*** find that the T90 observed with BAT in the 15-150 keV band is 13.2.s,corresponding to-1.4 s at z=*** once again gives rise to the issue of whether the progenitors of high-z GRBs are massive stars or mergers since the discovery of GRB 080913 at z=*** comparison with the T90 distribution in the burst frame of the current redshift-known GRB sample,we find that it is marginally grouped into the long group(Type II GRBs).The spectrum observed with both BAT and GBM is well fitted by a power-law with exponential cutoff,which yields an Ep=(50.4±7.0) *** event satisfies the Amati-relation well for Type II GRBs within their 3σ uncertainty *** results indicate that this event would be produced by the death of a massive *** on the Amati-relation,we derive its distance modulus,which follows the Hubble diagram of the concordance cosmology model at a redshift of-8.2.

关键词： gamma-ray bursts high energy phenomenon cosmology

Relations Between Characteristic Function,Positive P-Representation and Coherent Thermal State

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Communications in Theoretical physics 2007年第7期48卷 67-70页

作者： FAN Hong-Yi XU Xing-Lei department of Material Science and Engineering,University of Science and Technology of China,Hefei 2.002.,China2.department of {2.,Shanghai Jiao Tong University,Shanghai 2.0030,China3 department of {2.,Heze University,Heze 2.4015,China department of Material Science and Engineering University of Science and Technology of China department of physics Shanghai Jiao Tong University department of physics Heze University

We employ the coherent thermal states(a kind of entangled states)in thermal field dynamics to establisha complete entangled state formalism expressing pseudo-classical representations of density operator for light ***,the relationship between the coherent thermal state and the characteristic function and the positive Prepresentation in quantum optics theory are obtained.

关键词： coherent thermal state characteristic function positive P-representation

X-ray flares of γ-ray bursts: Quakes of solid quark stars?

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Science China(physics,Mechanics & Astronomy) 2009年第2期52卷 315-320页

作者： XU RenXin1 & LIANG EnWei2.1 School of physics and State Key Laboratory of Nuclear physics and Technology, Peking University, Beijing 100871, China 2.{2. of physics, Guangxi University, Nanning 530004, China 1. School of physics and State Key Laboratory of Nuclear physics and Technology Peking University Beijing 100871 China 2. department of physics Guangxi University Nanning 530004 China

A star-quake model is proposed to understand X-ray flares of both long and short γ-ray bursts (GRBs) in a solid quark star regime. Two kinds of central engines for GRBs are available if pulsar-like stars are actually (solid) quark stars, i.e., the SNE-type GRBs and the SGR-type GRBs. It is found that a quark star could be solidified about 103 to 106 s later after its birth if the critical temperature of phase transi- tion is a few Metga-electron-volts, and then a new source of free energy (i.e., elastic and gravitational ones, rather than rotational or magnetic energy) could be possible to power GRB X-ray flares.

关键词： γ-rays bursts: X-rays neutron stars elementary particles

I-V and C-V properties of TiO_2.thin film by pulsed-laser reactive deposition

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Chinese Science Bulletin 1998年第16期43卷 1344-1349页

作者： FU Zhengwen 1, ZHOU Mingfei 1, ZHANG Shengkun 2.CHEN Lianyao 2.and QIN Qizong 1 1. Laser Chemistry Institute, Fudan University, Shanghai 2.0433, China 2. department of physics, Fudan University, Shanghai 2.0433, China Laser Chemistry Institute Fudan University Shanghai China department of Pnysics Fudan University Shanghai China

TiO-2.thin films have bee deposited on p-Si(111) substrates by pulsed-laser ablation of metallic Ti target in the O-3 ambient. The current-voltage and capacitance-voltage of the Al/TiO-2.Si capacitors are measured. The results show that the dielectric constant of thin film after being annealed at 700℃ is found to be 46, and the border trap density and the interface state density at the TiO-2.p-Si interface are 1.8×10 12.cm -2.and 2.10 12.eV -1·cm -2. respectively. The conduction mechanisms of as-deposited films are also discussed.

关键词： TiO-2 dielectric properties electrical properties pulsed-laser deposition.

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 University,Xinjiang 832.03,China 2.School of Science,East China University of Science and Technology,Shanghai 2.02.7,China 3 Institute of Theoretical physics,School of physics and Information Optoelectronics,Henan University,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

EAM APPROACH TO ENTHALPY OF FORMATION OF ALKALI METAL ALLOYS

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中国有色金属学会会刊：英文版 1996年第4期6卷 52-56页

作者： Zhang Bangwei Ouyang Yifang Liao Shuzhi Jin Zhanpeng1 (International Centre for Materials physics,Shenyang 110015)2.(department of physics,Hunan University, Changsha 410082.3 (department of Materials Science and Engineering,Central South University of Tec ACAD SINICA INT CTR MAT PHYSSHENYANG 110015PEOPLES R CHINA HUNAN UNIV DEPT PHYSCHANGSHA 410082PEOPLES R CHINA CENT S UNIV TECHNOL DEPT MAT SCI & ENGNCHANGSHA 410083PEOPLES R CHINA HUNAN UNIV DEPT CHEM & CHEM ENGNCHANGSHA 410082PEOPLES R CHINA

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关键词： EAM approach enthalpy of formation alkali metal alloys

Molecular dynamics simulation of thermal stability of nanocrystalline vanadium

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Science China(Technological Sciences) 2006年第4期49卷 400-407页

作者： WEI Mingzhi1, XIAO Shifang1, YUAN Xiaojian2.& HU Wangyu1,2.1. Material Science and Engineering College, Hunan University, Changsha 410082. China 2. department of Applied physics, Hunan University, Changsha 410082. China Material Science Engineering College Hunan University Changsha 410082 China department of Applied physics Hunan University Changsha 410082 China

The microstructure and thermal stability of nanocrystalline vanadium with an average grain size ranging from 2.86 to 7.50 nm are calculated by means of the analytic embedded-atom method and molecular dynamics. The grain boundary and nanocrystal- line grain atoms are differentiated by the common neighbor analysis method. The results indicate that the fraction of grain boundary increases with the grain size decreasing, and the mean energy of atoms is higher than that of coarse crystals. The thermal-stable tem- peratures of nanocrystalline vanadium are determined from the evolution of atomic energy, fraction of grain boundary and radial distribution function. It is shown that the stable tem- perature decreases obviously with the grain size decreasing. In addition the reasons which cause the grain growth of nanocrystalline vanadium are discussed.

关键词： nanocrystalline, embedded-atom method, molecular dynamics, thermal stability.