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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 sciences, 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)

The gravity wave instability induced by photochemistry in summer polar mesopause region

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chinese Science Bulletin 2000年第3期45卷 267-272页

作者： Center for Space Science and Applied Research, chinese academy of sciences, beijing 100080, china laboratory of Numeric Study of Heliospheric physics, chinese academy of sciences, beijing 100080, china Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China laboratory of Numeric Study of Heliospheric physics Chinese Academy of Sciences Beijing China

The effect of diabatic process due to the photochemical heating and cooling on the gravity wave propagation in middle atmosphere is studied. A linear gravity wave model which considers the diabatic process is established. The unstable region and the growth rate of the gravity wave caused by photochemistry are calculated. And the comparison between the model and the adiabatic gravity wave theory of pure dynamics is made. The results indicate that the photochemical heating process can induce the instability of gravity wave at mesopause. The intensity of the instability becomes stronger as the temperature decreases. The temperature feature and the altitude characteristics of the instability are consistent with the observation. Therefore, the instability of the gravity wave induced by photochemistry may be an important mechanism in polar mesopause region in summer.

关键词： photochemistry instability gravity wave growth rate.

Improvement of refrigerant capacity of La_(0.67)Ca_(0.33)MnO_(3) single crystal with a few percent Fe doping

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Science china(physics,Mechanics & Astronomy) 2009年第6期52卷 809-812页

作者： LI GuoKe, ZHANG XiangQun, KOU ZhiQi, LI QingAn, SUN Young & CHENG ZhaoHua State Key laboratory of Magnetism, beijing national laboratory of condensed matter physics and institute of physics, chinese academy of sciences, beijing 100190, china State Key laboratory of Magnetism Beijing National Laboratory of Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing China

Large low-field-induced magnetic entropy changes, ΔSM, are observed in La0.67Ca0.33MnO3 and La0.67-Ca0.33Mn0.96Fe0.04O3 single crystals. The peaks of ΔSM broadened asymmetrically to high temperatures under higher magnetic fields for two materials should be attributed to the first-order magnetic phase transition at Tc. A small amount of iron doping results in an increase in the refrigerant capacity of the material though the magnetic entropy change decreases. The discovery of excellent magnetocaloric features of these single crystals in the low magnetic field can provide some ideas for exploring novel magnetic refrigerants operating under permanent magnet rather than superconducting one as magnetic field source.

关键词： single crystal magnetic entropy refrigerant capacity

Containerless solidification of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(22.5) glass-forming alloy in drop tube

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chinese Science Bulletin 2002年第20期47卷 1700-1703页

作者： LI Gong, SUN Liling & WANG WenkuiCollege of Material sciences and Engineering, Yanshan University, Qinhuangdao 066004, china Center for condensed matter physics, institute of physics, chinese academy of sciences, beijing 100080, china national Microgravit Coll. of Mat. Sci. and Engineering Yanshan University Qinhuangdao 066004 China Center for condensed matter physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China national Microgravity laboratory Chinese Academy of Sciences Beijing 100080 China

Droplets of Zr41Ti14Cu12.5Ni10Be22.5 glass forming alloys with different sizes are solidified in a drop tube containerless processing. Glass transition behavior, crystallization kinetics, and the phase evolution during annealing of the Zr41Ti14Cu12.5Ni10Be22.5 glassy spheres are investigated. The experimental results indicate that the apparent activation energy of the glass transition (Eg=435.5 kJ/mol), and the activation energy of the main crystallization reaction (Ep1 = 249.6 kJ/mol) are obviously different from those of bulk glass samples prepared by water quenched (Eg=559.1 kJ/mol and Ep1=192.5 kJ/mol). The difference is discussed in the view point of the atomic configuration of the liquid state of the metallic glass and nucleation mechanism.

关键词： ZrTiCuNiBe alloy containerless processing activation energy drop tube.

Magnetic Field Effects on Quantum-Dot Spin Valves

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Communications in Theoretical physics 2009年第3期51卷 555-562页

作者： GAO Jin-Hua,~1 SUN Qing-Feng,~1 and XIE Xin-Cheng~(1,2)1 beijing national Lab for condensed matter physics and institute of physics, chinese academy of sciences,beijing 100080, china2 Department of physics, Oklahoma State University, Stillwater, Oklahoma 74078, USA beijing national Lab for condensed matter physics and institute of physics Chinese Academy of Sciences Beijing 100080 China Department of physics Oklahoma State University Stillwater Oklahoma 74078 USA

We study the magnetic field effects on the spin-polarized transport of the quantum dot (QD) spin valve inthe sequential tunneling regime. A set of generalized master equation is derived. Based on that, we discuss the collinearand noncollinear magnetic field effects, respectively. In the collinear magnetic field case, we find that the Zeeman splittingcan induce a negative differential conductance (NDC), which is quite different from the one found in previous *** has a critical polarization in the parallel arrangement and will disappear in the antiparallel configuration. In thenoncollinear magnetic field case, the current shows two plateaus and their angular dependence is analyzed. Althoughsometimes the two current plateaus have similar angular dependence, their mechanisms are different. Our formalism isalso suitable for calculating the transport in magnetic molecules, in which the spin splitting is induced not by a magneticGeld but by the intrinsic magnetization.

关键词： spin value spintronics quantum dot

New quantum tunneling steps in Mn_(11)Cr/Mn_(12) mixed crystal

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Science china(physics,Mechanics & Astronomy) 2010年第9期53卷 1769-1771页

作者： ZHOU YuRong1,LI YanRong1,FAN ZhenJun2 & WANG YunPing1 1beijing national laboratory for condensed matter physics,institute of physics,chinese academy of sciences,beijing 100190,china 2School of Materials sciences and Technology,china University of Geosciences,beijing 430074,china beijing national laboratory for condensed matter physics Institute of Physics Chinese Academy of Sciences Beijing China School of Materials sciences and Technology China University of Geosciences Beijing China

Magnetic properties of Mn11Cr and Mn12 mixed crystal at low temperature are studied.A new set of quantum tunneling steps discovered in magnetization curves suggests that there may exist another kind of single molecula... 详细信息

关键词： quantum tunneling molecular magnet magnetization curve

Approaches to improving critical current density of YBCO superconducting thick films deposited by electrophoresis

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Science china(physics,Mechanics & Astronomy) 2004年第2期47卷 165-172页

作者： ZHU Yabin1,2, ZHOU Yueliang2, LIU Zhen2, WANG Shufang2, CHEN Zhenghao2, L?Huibin2, YANG Guozhen2, XIAO Ling3, REN Hongtao3, JIAO Yulei3 & ZHENG Minghui3 1. Department of physics, College of Science, beijing Jiaotong University, beijing 100044, china 2. laboratory of Optical physics, institute of physics and Center for condensed matter physics, chinese academy of sciences, beijing 100080, china 3. General Research institute for Nonferrous Metals, beijing 100088, china Correspondence should be addressed to Zhu Yabin (email: ybzhu@***) Department of physics College of Science Beijing Jiaotong University Beijing China laboratory of Optical physics institute of physics and Center for condensed matter physics Chinese Academy of Sciences Beijing China General Research institute for Nonferrous Metals Beijing China

Fabrication of YBCO superconducting thick films by electrophoresis has been widely reported. However, the value of critical current density (J c) is far from what the practical application requires. The superconducting thick films are obtained using top-seeded melt growth method with different proportional Y2BaCuO5 (Y211) addition. High-pressure oxygen has been used in the annealing process to improve the uniformity of the oxygen content in the superconducting thick films. When 40mol% Y211 powder is added to the YBa2Cu3O7–5 (Y123) powder,J c for the superconducting thick film by approaches described above reaches 7.008×103 A/cm2 (77 K, 0 T), which is greater than the value ever reported.

关键词： YBCO thick films, electrophoretic deposition, melt-textured.

Electrolytes in solid-state dye-sensitized nanocrystalline solar cells

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Progress in Natural Science:Materials International 2006年第7期16卷 679-683页

作者： AN Hongli, XUE Bofei, LI Dongmei, MENG Qingbo and GUO Lin ( beijing national laboratory for condensed matter physics, institute of physics, chinese academy of sciences, beijing 100080, china Department of Material Science and Engineering, Bei Hang University, beijing 100083, china) Bei Hang Univ Dept Mat Sci & Engn Beijing 100083 Peoples R China chinese Acad Sci Inst Phys Beijing Natl Lab Condensed Matter Phys Beijing 100080 Peoples R China

In this paper, the structure and operating principle of the dye-sensitized nanocrystalline solar cells (DSSC) are dis- cussed. The electrolytes can be divided into three types: liquid electrolyte, quasi-solid electrolyte and solid electrolyte. Based on the relevant study of our group, we summarized mainly the research progress of the quasi-solid electrolyte and solid electrolyte in solid-state DSSC.

关键词： solar cells electrolytes solid-state dye-sensitized.

Colossal magnetoresistive p-n junctions of perovskite oxide La_(0.9)Sr_(0.1)MnO_3/SrNb_(0.01)Ti_(0.99)O_3

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chinese Science Bulletin 2003年第13期48卷 1328-1330页

作者： L Huibin, DAI Souyu, CHEN Zhenghao, YAN Lei, ZHOU Yueliang & YANG Guozhen laboratory of Optical physics, institute of physics & Center for condensed matter physics, chinese academy of sciences, 100080 beijing, china laboratory of Optical physics Center for Condensed Matter Physics Chinese Academy of Sciences 100080 Beijing China

We have successfully fabricated the colossal magnetoresistive (CMR) p-n junctions of perovskite oxide La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 (LSMO/SNTO) with laser molecular beam epitaxy. The I-V characteristics of the LSMO/SNTO p-n junctions as a function of applied magnetic field (05 T) were studied between 100 and 300 K. We found that the p-n junction exhibited the CMR behavior. The CMR ratio rR/R0 (rR = RH - R0) is positive in magnetic fields below 0.13 T and at high temperature, while it displays a negative CMR near 100 K and in magnetic fields over 0.13 T. The CMR ratio values are 8% at 0.1 T and 13% at 5 T and 300 K, 40% at 0.1 T and 150 K, 10% at 0.13 T and 60% at 5 T and 100 K. The CMR behavior of the p-n junction is different from those of the LaMnO3 compound family.

关键词：巨磁电阻钙钛矿氧化物 LSMO/SNTO CMR 激光分子束外延超导体