检索结果-南通市图书馆

X（3.72. and Bound State Problem of D0*0（0 D*0）

在线全文

学校读者我要写书评

暂无评论

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 physics,{2. Academy of sciences,Beijing 100049,{3. 2.Department of physics,Peking University,Beijing 100871,{3. 3.Centro de Física Terica,Departamento de Física,Universidade de Coimbra,P-3.04-516,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(3.72. 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(3.72. bound state molecule

Electronic structure and magnetism of Fe-doped SiC nanotubes

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第9期53卷 1582-1589页

作者： ZHANG WeiHu1,2.3.ZHANG FuChun3.ZHANG ZhiYong4,LU ShuYuan5 & YANG YanNing3.1 Xi’an institute of Optics and Precision Mechanics,chinese Academy of sciences,Xi’an 710068,{3. 2.Graduate University of chinese Academy of sciences,Beijing 100049,{3. 3.College of physics and Electronic Information,Yan’an University,Yan’an 716000,{3. 4 Information Science and Technology Institution,Northwest University,Xi’an 71012.,{3. 5 Department of Telecommunications,Xi’an institute of Posts and Telecommunications,Xi’an 71012.,{3. Xi’an institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi’an China Graduate University of chinese Academy of sciences Beijing China College of physics and Electronic Information Yan’an University Yan’an China Information Science and Technology Institution Northwest University Xi’an China Department of Telecommunications Xi’an Institute of Posts and Telecommunications Xi’an China

The electronic structure and magnetic properties of Fe-doped SiC nanotubes are investigated by using the first-principles method based on density functional theory(DFT) in the local spin density approximation(LSDA).The calculation results indicate that the SiC nanotube of Fe substitution for C exhibits antiferromagnetism while ferromagnetism features prominently when Fe substitutes *** is a kind of half-metal magnetic *** formation energy calculation results show that the formation energy of ferromagnetic structure is {2.2.eV lower than that of antiferromagnetic *** atoms are more likely to replace Si ***-orbit coupling induces electron spin polarization in the ground ***,the doping Fe atoms make relaxation towards the outside of the tube to some extent and larger geometric distortion occurs when Fe substitutes C,but the whole geometric structure of SiC nanotubes is not damaged due to the *** is revealed in the calculation of energy band structure and density of states that more dispersed distribution of energy levels is produced near the Fermi *** Fe substitution for Si,obviously there are spin-split and intense p-d hybrid effects by Si {2. electron spins and Fe {2. electron spins localized at the exchanging interactions between magnetic transitional metal(TM) *** electronic density results indicate that system magnetic moments are mainly generated by the unpaired {2. electrons of Fe *** these results show that the transition metal doping SiC nanotube could be a potential route to fabricating the promising magnetic materials.

关键词： SiC nanotube the first-principles doped magnetic properties

Improving DNA damage repair ability of E. coli to UV-radiosensitivity by DNA-mediated gene transfer of low energy ion beam

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 1999年第19期44卷 1778-1783页

作者： SONG Daojun and YU XunCenter of Ion Beam Bioengineering, institute of Plasma physics , {2. Academy of {3. , Hefei 2.3}03., china College of Life Science , University of Science and Technology of china , Hefei 2.3}02., china Center of Ion Beam Bioengineering Institute of Plasma Physics Chinese Academy of Sciences Hefei China College of Life Science University of Science and Technology of China Hefei China

Using calcium chloride method of transfer gene as control, a new technique of transferring gene by low energy ion beam has been applied to the study of improving DMA damage repair ability of E. coli to UV-radiosensitivity. The genome DMA pieces of Deinococcus radio-durans, as 'foreign' genetic materials, were introduced into the UV-radiosensitive strains of E.

关键词： ion implantation Deinococcus radiodurans transfer gene survival rate unscheduled DNA synthesis.

在线全文

学校读者我要写书评

暂无评论

B_c Meson Studies

高能物理与核物理 2002年第Z1期26卷 1-10页

作者： CHANG Chao-Hsi (institute of Theoretical physics, {2. Academy of {3., Beijing 100080, china) Inst. of Theor. Phys. Chinese Acad. of Sci. Beijing 100080 China

Our studies on the meson Bc arc briefly *** decays of the meson Bc to a P-wave charmonium Xc or hc are reported comparatively precisely because they are fresh

关键词：高能物理核物理增刊张肇西 B_c Meson Studies Rev

Fabrication of atomically smooth SrRuO_3.thin films by laser molecular beam epitaxy

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2008年第7期51卷 745-749页

作者： LIU GuoZhen1, HE Meng1, JIN KuiJuan1, YANG GuoZhen1, Lü HuiBin1, ZHAO Kun2. ZHENG ShiJian3.& MA XiuLiang3.1 Beijing National Laboratory for Condensed Matter {2., institute of {2., {3. Academy of sciences, Beijing 100080, china 2.Department of Mathematics and {2., china University of Petroleum, Beijing 102.49, china 3.Shenyang National Laboratory for Materials Science, institute of Metal Research, {3. Academy of sciences, Shenyang 110016, china Beijing National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing China Department of Mathematics and physics China University of Petroleum Beijing China Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang China

high-quality SrRuO3.(SRO) thin films and SrTiO3.SRO bilayer were grown epitaxially on SrTiO3.(STO)(001) substrates by laser molecular beam epitaxy. The results of in situ observation of reflection high-energy electron diffraction and ex situ X-ray diffraction θ -2. scan indicate that the SRO thin films have good crystallinity. The measurements of atomic force microscopy and scan tunneling microscopy reveal that the surface of the SRO thin film is atomically smooth. The resistivity of the SRO thin film is 3.0 μΩ·cm at room temperature. Furthermore, the transmission electron microscopy study shows that the interfaces of STO/SRO and SRO/STO are very clear and no interfacial reaction layer was observed. The experimental results show that the SRO thin film is an excellent electrode material for devices based on perovskite oxide materials.

关键词： SrRuO3 thin film laser molecular beam epitaxy surface morphology

Isospin and symmetry energy study in nuclear EOS

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2011年第S1期54卷 141-148页

作者： TIAN WenDong1, MA YuGang1, CAI XiangZhou1, FANG DeQing1, WANG HongWei1 & WU HongLi1,2.1 Shanghai institute of Applied physics, {2. Academy of {3., Shanghai 2.1800, china 2.Graduate School of University of Science and Technology of china, Hefei 2.3}02., china Shanghai institute of Applied physics Chinese Academy of Sciences Shanghai China Graduate School of University of Science and Technology of china Hefei China

This paper summarizes the isoscaling and isospin related studies in asymmetry nuclear reactions by different dynamic and sta tistical models. Isospin dependent quantum molecular dynamics model (IQMD) and lattice gas model (LGM) are used to study the isoscaling properties and isoscaling parameters dependence on incident energies, impact parameters, temperature and other parameters. In the LGM model, the signal of phase transition has been found in free neutron (proton) chemical potential dif ference Δμn or Δμp as a function of temperature, or in free neutron and proton chemical potential difference Δμn-Δμp. Density dependence of symmetry energy coefficient Csym(ρ/ρ0) is also studied in the frame of LGM, with the potential parameters which can reproduce the nuclear ground state property, soft density dependence of symmetry energy is deduced from the sim ulation results. Giant dipole resonance (GDR) induced by isospin asymmetry in entrance channel is also studied via IQMD model, and the dynamic dipole resonance shows isospin sensitivity on the isospin asymmetry of entrance channel and sym metry energy of the nuclear equation of state (EOS). GDR can also be regarded as a possible isospin sensitive signature.

关键词： nuclear EOS isospin isoscaling density giant dipole resonance

The time and energy signals,counter plateau,energy resolution and gas gains performances of a new kind of micro-pattern gaseous detector-Micromegas

在线全文

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2008年第12期51卷 2208-2212页

作者： ZHANG XiaoDong1,2.YANG HeRun1,XU HuShan2.DUAN LiMin2.HU BiTao1,LI ChunYan2.& LI ZuYu2.1 School of Nuclear Science and Technology,Lanzhou University,Lanzhou 73.000,china 2.{2. of Modern physics,{3. Academy of sciences,Lanzhou 73.000,china School of Nuclear Science and Technology Lanzhou University Lanzhou China institute of Modern physics Chinese Academy of Sciences Lanzhou China

In present paper,a new Micromegas detector is developed,and its time and energy signals are obtained in the figure *** rising time of fast time signal is less than 2.ns due to the very fast collection of avalanche electrons,and the rising time of the energy pulse is about 100 ns,which is corresponding to the total collecting time of the electrons and ions in the avalanche *** counter plateau,energy resolution and the gas gains of the detector have been compared with other groups' experimental results and the Garfield simulation result.

关键词： micro-mesh gaseous structure time and energy signals energy resolution gas gain counter plateau

A low frequency piezoelectric power harvester using a spiral-shaped bimorph

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2006年第6期49卷 649-659页

作者： HU Yuantai1,2.HU Hongping2.& YANG Jiashi3.1. institute of Mechanics and Sensing Technology,Central South University,Changsha 410083.china 2. Department of Mechanics,Huazhong University of Science and Technology,Wuhan 43.074,china 3. Department of Engineering Mechanics,University of Nebraska,Lincoln,NE 68588-052.,USA institute of Mechanics and Sensing Technology Central South University Changsha China Department of Mechanics Huazhong University of Science and Technology Wuhan China Department of Engineering Mechanics University of Nebraska Lincoln USA

We propose a spiral-shaped piezoelectric bimorph power harvester operating with coupled flexural and extensional vibration modes for applications to low frequency energy sources. A theoretical analysis is performed and the computational results show that the spiral structure has relatively low operating frequency compared to beam power harvesters of the same size. It is found that to optimize the performance of a piezoelectric spiral-shaped harvester careful design is needed.

关键词： spiral-shaped bimorph,piezoelectric harvester,power density.

A one-dimensional heat transfer model of the Antarctic Ice Sheet and modeling of snow temperatures at Dome A, the summit of Antarctic Plateau

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2010年第5期53卷 763-772页

作者： CHEN BaiLian1,3. ZHANG RenHe2. SUN ShuFen1, BIAN LinGen2. XIAO CunDe4,2.& ZHANG TingJun5 1 institute of Atmospheric {2., chinese Academy of {3., Beijing 10002., china 2.chinese Academy of Meteorological {3., Beijing 100081, china 3.Graduate University of chinese Academy of {3., Beijing 100049, china 4 Cold and Arid Regions Environmental and Engineering Research institute, chinese Academy of {3., Lanzhou 73.000, china 5 The National Snow and Ice Data Center, University of Colorado, Boulder, CO 803.9-0449, USA institute of Atmospheric physics Chinese Academy of Sciences Beijing China Graduate University of chinese Academy of sciences Beijing China chinese Academy of Meteorological sciences Beijing China Cold and Arid Regions Environmental and Engineering Research institute Chinese Academy of Sciences Lanzhou China The National Snow and Ice Data Center University of Colorado Boulder USA

A vertical one-dimensional numerical model for heat transferring within the near-surface snow layer of the Antarctic Ice Sheet was developed based on simplified parameterizations of associated physical processes for the atmosphere, radiation, and snow/ice systems. Using the meteorological data of an automatic weather station (AWS) at Dome A (80°2.′S, 70°2.′E), we applied the model to simulate the seasonal temperature variation within a depth of 2. m. Comparison of modeled results with observed snow temperatures at 4 measurement depths (0.1, 1, 3. 10 m) shows good agreement and consistent seasonal variations. The model results reveal the vertical temperature structure within the near-surface snow layer and its seasonal variance with more details than those by limited measurements. Analyses on the model outputs of the surface energy fluxes show that: 1) the surface energy balance at Dome A is characterized by the compensation between negative net radiation and the positive sensible fluxes, and 2. the sensible heat is on average transported from the atmosphere to the snow, and has an evident increase in spring. The results are considered well representative for the highest interior Antarctic Plateau.

关键词： Antarctic Ice Sheet near-surface layer energy transfer numerical model