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CHEMICAL STRUCTURE DEPENDENCE OF THE INTERNAL ENERGY CONTRIBUTION IN RUBBER ELASTICITY

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chinese Journal of Polymer Science 2001年第5期19卷 447-449页

作者： Juan Sun Xiao-zhen Yang Polymer physics laboratory Center for Molecular {2., institute of Chemistry chinese academy of sciences beijing 100080 China 中科院化学所高分子物理及化学国家重点实验室北京

Conformational elasticity theory recently developed has been used to explore the internal energy contribution to the elastic force f(e)/f as a function of strain for poly(cis-1,4-isoprene) and poly(trans-1,4-isoprene). Calculated f(e)/f values are in good agreement with those obtained experimentally. Results show that behavior of f(e)/f is mainly contributed by chemical structure, or intramolecular interaction, supporting the experimental observations, and that the internal energy contribution is strain dependent.

关键词： conformational elasticity theory internal energy contribution poly(cis-1,4-isoprene) poly(trans-1,4-isoprene)

Suppressing the multimodal size distribution of InAs/GaAs quantum dots through flattening the surface fluctuation

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Science China(physics,Mechanics & Astronomy) 2010年第5期53卷 788-792页

作者： WANG Lu1,2.LI MeiCheng1,WANG WenXin2.GAO HanChao2.TIAN HaiTao2.XIONG Min1 & ZHAO LianCheng1 1 School of Material Science and Technology,Harbin institute of Technology,Harbin 150001,China 2.national {2. for condensed matter physics,institute of physics,chinese academy of sciences,beijing 100190,China School of Material Science and Technology Harbin Institute of Technology Harbin China national laboratory for {2. matter physics Institute of Physics Chinese Academy of Sciences Beijing China

A method of suppressing the multimodal size distribution of InAs/GaAs quantum dots(QDs) using molecular beam epitaxy through flattening the substrate surface is reported in this *** is found that the surface roughness plays an important role in the growth of QDs through continuous surface evolution(SEQDs).SEQDs are the main components of small QD ensemble in QDs with multimodal size *** is suggested that most of the SEQDs are very likely to nucleate during the growth interruption rather than during the *** growth of QDs on a smoother surface has largely reduced the density of *** photoluminescence line width of uniform QDs is found to be only 17 meV at a low temperature.

关键词： quantum dots multimodal surface fluctuation

Band gap anomaly and topological properties in lead chalcogenides

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chinese physics B 2016年第3期25卷 27-34页

作者：聂思敏许霄琰徐刚方忠 beijing national {2. for condensed matter physics and Institute of Physics Chinese Academy of Sciences Beijing 1O0190 China Collaborative Innovation Center of Quantum matter Beijing 100084 China

Band gap anomaly is a well-known issue in lead chalcogenides PbX （X = S, Se, Te, Po）. Combining ab initio calculations and tight-binding （TB） method, we have studied the band evolution in PbX, and found that the band gap anomaly in PbTe is mainly related to the high on-site energy of Te 5s orbital and the large s-p hopping originated from the irregular extended distribution of Te 5s electrons. Furthermore, our calculations show that PbPo is an indirect band gap （6.5 meV） semiconductor with band inversion at L point, which clearly indicates that PbPo is a topological crystalline insulator （TCI）. The calculated mirror Chern number and surface states double confirm this conclusion.

关键词： band gap anomaly lead chalcogenides indirect band gap semiconductor topological crystallineinsulator

Inertial theory of the mean Hadley circulation under the condition of nonstatic equilibrium

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Science China Earth sciences 2006年第5期49卷 546-553页

作者： CHAO Jiping1 & LIU Fei2.3 1. national Marine Environmental Forecasting Center, beijing 100081, China 2. Key {2. Regional Climate-Environment for Temperate East Asia, institute of Atmospheric physics, chinese academy of sciences, beijing 10002., China 3. Graduate University of chinese academy of sciences, beijing 100049, China national Marine Environmental Forecasting Center Beijing China Key laboratory Regional Climate-Environment for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

Tropical atmosphere is divided into two layers, the layer near the ground is the planet boundary layer, where the motion is linear, if the radiation equilibrium temperature is given at the top of the boundary layer, the vertical motion there can be obtained. It is the non-viscous ideal atmos- pheric layer above the boundary one, where the motion is nonlinear. After getting the conservation laws of angular momentum, potential temperature and potential vortex, the inertial theory of the Hadley circulation driven by the vertical motion of the boundary layer is established, followed by sev- eral examples of its application.

关键词： Hadley circulation, inertial theory, conservation laws of angular momentum, potential temperature and potential vortex.

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 {2. for condensed matter 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 centered 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

Mechanisms of the pancake vortex and vortex line movement in the high T_c superconductors Bi_2.r_2.aCu_2._8+δ and La_(1.93)Sr0.0_7CuO_4+δ

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Science China(physics,Mechanics & Astronomy) 2007年第2期50卷 240-248页

作者： WANG WeiXian1,ZHOU Fang2.TAN Shun1,WU Huan1 & ZHANG YuHeng1 1 national High Magnetic Field laboratory,University of Science and Technology of China,Hefei 2.002.,China 2.national laboratory for Superconductivity,lnstitute of physics and the Center for condensed matter physics,chinese academy of sciences,beijing 100080,China national High Magnetic Field laboratory University of Science and Technology of China Hefei China national laboratory for Superconductivity Institute of Physics and the Center for Condensed Matter Physics Chinese Academy of Sciences Beijing China

In the strict sense, it is not very clear why with magnetic field increasing, the normal-superconductive (NS) transition becomes broad for Bi2.r2.aCu2.8+δ(Bi2.12. while the NS transitions are almost parallel for La193Sroo7Cu04+δ(La2.4). In this paper, R-T relations are measured by the six-probe method. We propose a moving mechanism of the pancake vortex and vortex line for Bi2.12. The theoretical curves fit the experiment data well.

关键词： superconductivity superconductive pancake vortex dynamics

Fluorescence dynamics of interactions between polyamide PyPyPyβDp and DNA

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Science China Chemistry 2006年第1期49卷 75-80页

作者： ZHANG Huijuan1,2. WANG Jin3, WU Yishi1, YUAN Gu3, AI Xicheng1, WANG Li4 & ZHANG Jianping1 1. State Key laboratory for Structural Chemistry of Unstable and Stable Species, institute of Chemistry, {2., beijing 100080, China 2. School of Life Science and Technology, beijing institute of Technology, beijing 100081, China 3. College of Chemistry and Molecular Engineering, Peking University, beijing 100080, China 4. Center for condensed matter physics, institute of physics, {2., beijing 100080, China Correspondence should be addressed to Ai Xicheng and Zhang Jianping State Key laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing China School of Life Science and Technology Beijing Institute of Technology Beijing China College of Chemistry and Molecular Engineering Peking University Beijing China Center for condensed matter {2. Institute of Physics Chinese Academy of Sciences Beijing China

The photophysical properties of the polyamide PyPyPyβDp (PPP) were investigated by means of steady-state absorption and fluorescence spectroscopies, as well as time-resolved fluo-rescence spectroscopy. It was found that the excited-state properties of PPP are very sensitive to solvents. In TKMC buffer PPP exhibited weak fluorescence with a decay time constant of 16 ps, while with the decrease of the solvent polarity PPP showed the blue-shifted peak position, increased inten-sity and lengthened life-time for its fluorescence behavior. In the presence of calf thymus DNA, it was observed that the fluorescence intensity was enhanced and the fluorescence lifetime increased from 16 to 32.ps for PPP, which verified that PPP bound into the minor groove of DNA duplex.

关键词： polyamide (PPP), calf thymus DNA (ctDNA), time-resolved fluorescence spectroscopy, recognition dynamics.

Fabrication and properties of the meander nanowires based on ultra-thin Nb films

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chinese physics B 2014年第8期23卷 521-526页

作者：赵璐金贻荣李洁邓辉郑东宁 beijing national {2. for condensed matter physics Institute of Physics Chinese Academy of Sciences

We report the fabrication and the study of superconducting properties of ultra-thin Nb superconducting meander nanowires, which can be used as superconducting nanowire single-photon detectors （SNSPDs）. The ultra-thin （about 7- nm thick） Nb films are patterned into micro-bridges, and 100-nm wide meander nanowires by using e-beam lithography （EBL）. The average transition temperature （Tc） of the nanowires is about 4.8 K and the critical current density jc is about 2.8 × 10^6 A/cm2. Superconducting characteristics of the specimens at different applied magnetic fields up to 8 T （parallel or perpendicular to the specimen） are systematically investigated. The normalized temperature t （= T/Tc） dependences of the parallel critical field （HcⅡ） for both the micro-bridge and the meander nanowire are almost the same, following the Ginzburg and Landau （GL） formalism for ultra-thin films. However, in perpendicular field and in the vicinity of Tc （〉 0.95Tc）, the critical field Hc⊥ of the nanowire exhibits a down-turn curvature nonlinear temperature dependence while the micro-bridge displays a linear temperature dependence. The nonlinear behavior of Hc⊥ in the nanowire is believed to be due to the fact that in the vicinity of Tc the coherence length becomes larger than the line width. Additionally, the localization of carriers in the nanowire could also contribute to the nonlinear behavior. The resistive transitions could be described by the phase-slip model for quasi-one-dimensional system. Moreover, the hysteresis in I-V curve of the meander nanowires can be illustrated by a simple model of localized normal hotspot maintained by Joule heating.

关键词： Nb meander nanowire critical temperature critical field critical current

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 {2. for condensed matter 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