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Quantum phase transitions of fermionic atoms in an anisotropic triangular optical lattice

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chinese physics B 2013年第11期22卷 216-221页

作者：保安陈耀桦章晓中 laboratory of Advanced Materials School of Materials Science and Engineering Tsinghua University beijing National laboratory for {2.{3. physics Institute of Physics Chinese Academy of Sciences

The effect of anisotropy caused by a confining potential on the properties of fermionic cold atoms in a triangular optical lattice is systematically investigated by using the dynamical cluster approximation combined with the continuous time quantum Monte-Carlo algorithm. The quantum phase diagrams which reflect the temperature-interaction relation and the competition between the anisotropic parameter and the interaction are presented with full consideration of the anisotropy of the system. Our results show that the system undergoes a transition from Fermi liquid to Mott insulator when the repulsive interaction reaches a critical value. The Kondo effect also can be observed in this system and the pseudogap is suppressed at low temperatures due to the Kondo effect. A feasible experiment protocol to observe these phenomena in an anisotropic triangular optical lattice with cold atoms is proposed, in which the hopping terms are closely related to the lattice confining potential and the atomic interaction can be adjusted via the Feshbach resonance.

关键词： triangular optical lattice cold atoms cluster dynamical approximation

Isospin-dependent relativistic microscopic optical potential in the Dirac Brueckner-Hartree-Fock method

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Science China(physics,Mechanics & Astronomy) 2004年第2期47卷 189-198页

作者： RONG Jian1 & MA Zhongyu1,2.3.1. China institute of Atomic Energy, beijing 102.13. China 2. {2. of Nuclear Theoretical {3., National laboratory of Heavy Ion Accelerator of Lanzhou, Lan-zhou 73.000, China 3. institute of Theoretical {3., chinese academy of sciences, beijing 100080, China Correspondence should be addressed to Rong Jian (email: jrong@***) China institute of Atomic Energy Beijing China center of Nuclear Theoretical physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China institute of Theoretical physics Chinese Academy of Sciences Beijing China

The relativistic microscopic optical potential in the asymmetric nuclear matter is studied in the framework of the Dirac Brueckner-Hartree-Fock method. A new decomposition of the Dirac structure of the nuclear self-energy in nuclear matter is adopted. The self-energy of a nucleon with E > 0 in nuclear matter is calculated with the G matrix in the Hartree-Fock approach. The optical potential of a nucleon in the nuclear medium is identified with the nucleon self-energy. The energy and asymmetric parameter dependence of the relativistic optical potentials for proton and neutron are discussed. The resulting Schroedinger equivalent potentials have reasonable behaviors of the energy dependence. The asymmetric parameter dependence of relativistic optical potentials and Schroedinger potentials are emphasized.

关键词： Dirac Brueckner Hartree-Fock, relativistic microscopic optical potential, asymmetric nuclear matter, isospin-dependence.

量子动边界广义含时谐振子之精确的指数-正弦型演化态

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物理学报 2001年第9期50卷 1654-1660页

作者：李伯臧李玲中国科学院物理研究所和凝聚态物理中心山西大学物理系和理论物理研究所太原030006

研究了被局限于区间 [0 ,L(t) ]中运动的动边界广义含时谐振子量子系统 ,其Hamiltonian为坐标与动量的非齐次含时二次型 .求出了具有“指数正弦型”演化态的充要条件以及相应的正交归一完备的精确演化态系列 .此结果不但几乎包含了已... 详细信息

研究了被局限于区间 [0 ,L(t) ]中运动的动边界广义含时谐振子量子系统 ,其Hamiltonian为坐标与动量的非齐次含时二次型 .求出了具有“指数正弦型”演化态的充要条件以及相应的正交归一完备的精确演化态系列 .此结果不但几乎包含了已有结果作为特例 ,还涵盖了相当广泛的范围 .此外 ,澄清了个别作者关于对时间的微商的一个误解 ,指出对时空坐标的微商均具有寻常的含义 .

关键词：动边界量子系统广义含时谐振子精确解量子力学微商动边界广义含时谐振子量子系统指数-正弦型演化态

Effect of ambient oxygen pressure on structural, optical and electrical properties of SnO_2.thin films

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Rare Metals 2006年第6期25卷 693-696页

作者： ZHAO Songqing ZHOU Yueliang WANG Shufang ZHAO Kun HAN Peng beijing National laboratory for {2.{3. physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China Department of Mathematics and physics China University of Petroleum Beijing 102249 China

PolycrystaUine SnO2.thin films were deposited on sapphire substrates at 450℃ under different ambient oxygen pressures by pulsed laser deposition technique. The effect of ambient oxygen pressure on the structural, optical and electrical properties of SnO2.thin films was studied. X-my diffraction and Hall measurements show that increasing the ambient oxygen pressure can improve crystallization of the films and decrease resistivity of the films. A violet emission peak {3.ed at 409 nm was observed from photoluminescence measurements for SnO2.films under deposition ambient oxygen pressure above 5 Pa, which is related to the improvement of crystalline of the films.

关键词： tin oxide pulsed laser deposition oxygen pressure PLD resistivity

A facile and efficient dry transfer technique for two-dimensional Van der Waals heterostructure

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chinese physics B 2017年第8期26卷 417-422页

作者：谢立杜罗军卢晓波杨蓉时东霞张广宇 beijing National laboratory for {2.{3. physics and institute of physics Chinese Academy of Sciences(CAS)Beijing 100190China School of Physical Science University of Chinese Academy of SciencesBeijing 100190China Collaborative Innovation center of Quantum matter Beijing 100190China beijing Key laboratory for Nanomaterials and Nanodevices Beijing 100190China

Two-dimensional （2.） Van der Waals heterostructures have aroused extensive concerns in recent years. Their fabrica- tion calls for facile and efficient transfer techniques for achieving well-defined structures. In this work, we report a simple and effective dry transfer method to fabricate 2. heterostructures with a clean interface. Using Propylene Carbonate （PC） films as stamps, we are able to pick up various 2. materials flakes from the substrates and unload them to the receiving substrates at an elevated temperature. Various multilayer heterostructures with ultra-clean interfaces were fabricated by this technique. Furthermore, the 2. materials can be pre-pattemed before transfer so as to fabricate desired device structures, demonstrating a facile way to promote the development of 2. heterostructures.

关键词： two-dimensional materials Van der Waals heterostructure Propylene Carbonate transfer

Spin-glass like behaviors in La_(1-x)Tb_xMnO_3.perovskite

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Science China(physics,Mechanics & Astronomy) 2009年第12期52卷 1893-1897页

作者： ZHANG YingTang1,2.3.WANG ChunChang2.4,LIU WeiBin1,WANG Zhong3.LU HuiBin2.& CHEN ZiYu1 1 Department of {3.,beijing University of Aeronautics and Astronautics,beijing 100191 2.3. of {3. & center for condensed matter {3.,chinese {13. of sciences,beijing 100190 3.School of Material Science & Engineering,Shaanxi University of Technology,Hanzhong 72.003.4 {3. of Superconducting and Electronic Materials,Wollongong University,Northfield Ave,Gwynneville,NSW 2.2.,Australia Department of physics Beijing University of Aeronautics and Astronautics Beijing China institute of physics & {2. for{3. matter physics Chinese Academy of Sciences Beijing China School of Material Science & Engineering Shaanxi University of Technology Hanzhong China institute of Superconducting and Electronic Materials Wollongong University Gwynneville Australia

A series of samples of La1-xTbxMnO3.(0≤x≤0.15) are prepared. The static and dynamic magnetizations of La1-xTbxMnO3.have been investigated. The results indicate that the spins with the short-range order are frozen into random direction at low enough temperatures which leads to the samples exhibiting the spin-glass like behavior. It is considered that the spin-glass like behavior originates from the competition between ferromagnetic double exchange among Mn3. and Mn2. and antiferromagnetic superex-change among Mn3. and Mn3.,as well as Tb3. and Tb3..

关键词： La1-xTbxMnO3 spin-glass-like behavior short-range order

Effects of gravity on the microstructure of Zr_(41)Ti_(14)-Cu_(12.5)Ni_(10)Be_(2..5) bulk glass forming alloy

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chinese Science Bulletin 2001年第11期46卷 961-963页

作者： LI Gong, ZHAN Zaiji, WANG Limin, CAO Limin, SUN Liling, DAI Daoyang, ZHANG Jun & WANG Wenkuiinstitute of physics, {2. for{3. matter physics, chinese academy of sciences, beijing 100080, China Department of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, China institute of physics Center for Condensed Matter Physics Chinese Academy of Sciences Beijing China Department of Materials Science and Engineering Yanshan University Qinhuangdao China

The ZrTiCuNiBe alloy is melt and solidified by Bridgman unidirectional solidification on two gravity field orientations (the gravity field orientation is parallel and opposite to solidification direction). Effects of gravity on morphology and microstructure are investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD). When gravity field orientation is parallel to solidificationdirection, less needle-like primary phase is embedded in a matrix eutectic; when gravity field orientation is opposite to solidification direction, a large amount of coarser needle-like primary phases were observed.

关键词： gravity field unidirectional solidification bulk amor- phous alloy.

THE LIGHT INDUCED CHANGE IN TRANSIENT PHOTOCONDUC-TIVITY OF POLYMORPHOUS SILICON FILMS

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Acta Metallurgica Sinica(English Letters) 2001年第6期14卷 453-456页

作者： S.B. Zhang, G.L. Kong, Y. Y. Xu, Y.Q. Wang, H.W. Diao and X.B. Liao (State laboratory for Surface physics, {2. of Semiconductors &{3. for condensed matter physics, chinese academy of sciences, beijing 100083. China) Inst. of Semiconduct. Chinese Acad. of Sci. Beijing 100083 China

The decays of transient photoconductivity and their light-induced changes of polymorphous silicon (pm-Si:H) films were investigated. The decays can be fit fairly well by a sum of two exponential decay functions, which indicates that there are two kinds of traps contributing to the process. The light-induced changes of the concentration and energy level of the traps were estimated. The results show that the light-induced changes in trap energy position Et, trap concentration Nt as well as photoconductivity are markedly less for pm-Si:H than that for a-Si:H.

关键词： light-induced change transient film

The guanidine hydrochloride-induced denaturation of CP43.and CP47 studied by terahertz time-domain spectroscopy

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Science China(Life sciences) 2007年第3期50卷 350-355页

作者： QU YuanGang1,3. CHEN Hua2. QIN XiaoChun1, WANG Li2. LI LiangBi1 & KUANG TingYun1 1 Key laboratory of Photosynthesis and Environmental Molecular Physiology, {3. of Botany,{2., {3. 100093. China 2.laboratory of optical physics, institute of physics and center for condensed matter physics,{2., beijing 100080, China 3.Graduate University of{2., {3. 100049, China Key laboratory of Photosynthesis and Environmental Molecular Physiology Institute of Botany Chinese Academy of SciencesBeijing 100093 China Graduate University of chinese academy of sciences Beijing 100049 China laboratory of optical {2. Institute of Physics and Center for Condensed Matter Physics Chinese Academy of SciencesBeijing 100080 China Key laboratory of Photosynthesis and Environmental Molecular Physiology Institute of Botany Chinese Academy of SciencesBeijing 100093 China

Terahertz time-domain spectroscopy (THz-TDS) is a new technique in studying the conformational state of a molecule in recent years. In this work, we reported the first use of THz-TDS to examine the dena- turation of two photosynthesis membrane proteins: CP43.and CP47. THz-TDS was proven to be useful in discriminating the different conformational states of given proteins with similar structure and in monitoring the denaturation process of proteins. Upon treatment with guanidine hydrochloride (GuHCl), a 1.8 THz peak appeared for CP47 and free chlorophyll a (Chl a). This peak was deemed to originate from the interaction between Chl a and GuHCl molecules. The Chl a molecules in CP47 interacted with GuHCl more easily than those in CP43.

关键词： CP The guanidine hydrochloride-induced denaturation of CP43.and CP47 studied by terahertz time-domain spectroscopy THz time