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

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science china({2.,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, {2. 2. Laboratory of Optical physics, Institute of physics and center for Condensed Matter physics, chinese academy of sciences, Beijing 100080, {2. 3. General Research Institute for Nonferrous Metals, Beijing 100088, {2. Correspondence should be addressed to Zhu Yabin (email: ybzhu@***) 1. Department of physics College of Science Beijing Jiaotong University 100044 Beijing China 2. Laboratory of Optical physics Institute of physics and {2. for Condensed Matter physics Chinese Academy of Sciences 100080 Beijing China 3. General Research Institute for Nonferrous Metals 100088 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 Y2.aCuO5 (Y2.1) 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% Y2.1 powder is added to the YBa2.u3O7–5 (Y12.) 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.

Statistical theory for hydrogen bonding fluid system of A_aD_d type (I): The geometrical phase transition

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science china Chemistry 2006年第6期49卷 499-506页

作者： WANG Haijun1,2. HONG Xiaozhong3, GU Fang1 & BA Xinwu1 1. College of Chemistry and Environment science, Hebei University, Baoding 071002. china 2. International {2. for Materials physics, chinese academy of sciences, Shenyang 110016, china 3. College of physics science and Technology, Hebei University, Baoding 071002. china 1. College of Chemistry and Environment science Hebei University Baoding 071002 China 2. International center for Materials physics Chinese Academy of Sciences Shenyang 110016 China 3. College of physics science and Technology Hebei University Baoding 071002 China

The influence of hydrogen bonds on the physical and chemical properties of hydrogen bonding fluid system of AaDd type is investigated from two viewpoints by the principle of statistical mechanics. In detail, we proposed two new ways that can be used to obtain the equilibrium size distribution of the hydrogen bonding clusters, and derived the analytical expression of a relationship between the hydrogen bonding free energy and hydrogen bonding degree. For the nonlinear hydrogen bonding systems, it is shown that the sol-gel phase transition can take place under proper conditions, which is further proven to be a kind of geometrical phase transition rather than a thermodynamic one. Moreover, several problems associated with the geometrical phase transition and liquid-solid phase transition in nonlinear hydrogen bonding systems are discussed.

关键词： hydrogen bonding fluid, equilibrium free energy, geometrical phase transition.

Some evidence of drying trend over northern china from 1951 to 2.04

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chinese science Bulletin 2006年第23期51卷 2913-2925页

作者： MA Zhuguo1,2.& FU Congbin1,2.1. Key Laboratory of Regional Climate-Environment for Temperate East Asia, chinese academy of sciences, Beijing 10002., china 2. START Regional {2. for Temperate East Asia, Institute of Atmos-pheric physics, chinese academy of sciences, Beijing 10002., china Key Laboratory of Regional Climate-Environment for Temperate East Asia Chinese Academy of Sciences Beijing 100029 China START Regional center for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The surface wetness index, Palmer drought sererity index and the retrieval of soil moisture over china were calculated using monthly precipitation and monthly mean surface air temperature. Based on the contrast analysis of the variation of the above three indices and precipitation, the dry/wet spatio-temporal pattern of northern china in the last 54 years was revealed, and the evidence of drying trend over northern china was analyzed, especially. The results show the following four facts: (1) The drying trend is the main characteristic of the eastern part of Northwest china and the central part of North china since the 1980s and it was enhanced in the last 15 years mainly due to the precipitation decrease and the temperature increase; (2. During the last 54 years, there was only one dry/wet shift at the interdecadal scale occurring in the eastern part of Northwest china and the central part of North china in the late 1970s, which was related to 1977/1978 global abrupt change, whereas there were three shifts in Northeast china, one was in the mid 1990s and the other two were in 1965 and 1983, respectively; (3) Unlike the variation trend of other subregions of northern china, the western part of Northwest china is currently located in a relatively wetting period, which is weak-ened due to the temperature increase; (4) The extreme drought frequency is obviously increasing in the eastern part of Northwest china, the central part of North china and Northeast china since the 1980s, which is closely related to the precipitation decrease and temperature increase in these subregions.

关键词：中国北方干燥趋向干旱索引气候背景

From quantum spectra to classical orbits: Varying rectangular billiards

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Progress in Natural science:Materials International 2008年第8期18卷 927-930页

作者： Jun Lu * Department of Foundational science, Beijing Union University, Beijing 100101, china Institute of {2. physics, chinese academy of sciences, Beijing 100080, china Department of Foundational science Beijing Union University Beijing 100101 China Institute of theoretical physics Chinese Academy of Sciences Beijing 100080 China

The quantum-spectrum function is introduced by means of the eigenvalues and the eigenfunctions in the system of varying rectangular billiards. It is found that the Fourier transform of the quantum-spectrum function corresponds with the classical orbits in the system. These results give new evidence about the classical-quantum correspondence.

关键词： Quantum spectrum Classical-quantum correspondence Semiclassical physics

Explicit analytical solutions of the anisotropic Brinkman model for the natural convection in porous media(Ⅱ)

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science china({2.,Mechanics & Astronomy) 2005年第4期48卷 422-430页

作者： CAI Ruixian1, GOU Chenhua1, 2.& ZHANG Na1 1. Institute of Engineering Thermophysics, chinese academy of sciences, Beijing 100080, {2. 2. Graduate School, chinese academy of sciences, Beijing 100080, {2. 1. Institute of Engineering Thermophysics Chinese Academy of Sciences 100080 Beijing China 2. Graduate School Chinese Academy of Sciences 10080 Beijing China

Some algebraically explicit analytical solutions are derived for the anisotropic Brinkman model―an improved Darcy model―describing the natural convection in porous media. Besides their important theoretical meaning (for example, in analyzing the non-Darcy and anisotropic effects on the convection), such analytical solutions can be the benchmark solutions that can promote the development of computational heat and mass transfer. Some solutions considering the anisotropic effect of permeability have been given previously by the authors, and this paper gives solutions including the anisotropic effect of thermal conductivity and the effect of heat sources.

关键词： explicit analytical solution, porous medium, natural convection, Brinkman model, anisotropic.

Two Higgs bi-doublet left-right model with spontaneous P and CP violation

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science china({2.,Mechanics & Astronomy) 2008年第12期51卷 1808-1825页

作者： WU YueLiang 1↑ & ZHOU YuFeng2.1 Kavli Institute for theoretical physics {2., Institute of theoretical physics, chinese academy of Sci- ences, Beijing 100190, {2. 2.KEK, Tsukuba, 305-0801, Japan 1. Kavli Institute for theoretical physics {2. Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China 2. KEK Tsukuba 305-0801 Japan

A left-right symmetric model with two Higgs bi-doublet is shown to be a consistent model for both spontaneous P and CP violation. The flavor changing neutral cur- rents can be suppressed by the mechanism of approximate global U(1) family symmetry. The constraints from neural K meson mass difference ΔmK are calcu- lated and it is demonstrated that a right-handed gauge boson W2.contribution in box-diagrams with mass well below 1 TeV is allowed due to a cancelation caused by a light-charged Higgs boson with a mass range of 150-300 GeV. The W2.con- tribution to εK can be suppressed from an appropriate choice of additional CP phases appearing in the right-handed Cabbibo-Kobayashi-Maskawa matrix. The model is also found to be fully consistent with B0 mass difference ΔmB and the mixing induced CP violation sin2.J/ψ , which is usually difficult for the model with only one Higgs bi-doublet. The new physics beyond the standard model can be directly searched at the colliders LHC and ILC.

关键词： left-right symmetry spontaneous P and CP violation two Higgs bi-doublets new physics

Finding Signals for Plant Promoters

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Genomics, Proteomics & Bioinformatics 2003年第1期1卷 68-73页

作者： Weimou ZhengInstitute of theoretical physics, {2., Beijing 100080, china Beijing GenomicsInstitute, {2., Beijing 101300, china Institute of theoretical physics Chinese Academy of Sciences Beijing 100080 China Beijing Genomics Institute Chinese Academy of Sciences Beijing 101300 China

The strongest signal of plant promoter is searched with the model of single motif with two types. It turns out that the dominant type is the TATA-box. The other type may be called TATA-less signal, and may be used in gene finders for promoter recognition. While the TATA signals are very close for the monocot and the dicot, their TATA-less signals are significantly different. A general and flexible multi-motif model is also proposed for promoter analysis based on dynamic programming. By extending the Gibbs sampler to the dynamic programming and introducing temperature, an efficient algorithm is developed for searching signals in plant promoters.

关键词： for on is as et Pro Finding Signals for Plant Promoters been of into

Patterns of platinum-group elements in mantle peridotite, granulite xenoliths and basalt in Hannuoba

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chinese science Bulletin 1999年第18期44卷 1676-1681页

作者： CHU Xuelei, LI Xiaolin, XU Jiuhua and LIU Jianming1. The Research center of Mineral Resources Exploration , chinese academy of sciences , Beijing 100101, {2. 2. Institute of Geology , chinese academy of sciences , Beijing 10002., {2. 3. Institute of High Energy physics , chinese academy of sciences , Beijing 100817 , {2. 4. Beijing University of science and Engineering , Beijing 100083, {2. Corresponding author The Research center of Mineral Resources Exploration Chinese Academy of Sciences Beijing China Institute of Geology Chinese Academy of Sciences Beijing China Institute of High Energy physics Chinese Academy of Sciences Beijing China Beijing University of science and Engineering Beijing China

Neutron activation analysis after preconcentration of nickel sulfide fire assay was used in measurement of Ru, Ph, Pd, Os, Ir, Pt (i.e. PGE elements) and Au concentrations for basalt, mantle and granulite xenoliths in Hannuoba. The chondrite- and primitive mantle-normalized PGE patterns generally exhibit flat (for Iherzolite), negative slope (for harzburgite),

关键词： mantle xenolith granulite xenolith basalt platinum-group element Hannuoba.

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

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science china({2.,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 physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lan-zhou 730000, china 3. Institute of theoretical physics, chinese academy of sciences, Beijing 100080, china Correspondence should be addressed to Rong Jian (email: jrong@***) 1. china Institute of Atomic Energy 102413 Beijing China 2. center of Nuclear theoretical {2. National Laboratory of Heavy Ion Accelerator of Lanzhou 730000 Lanzhou China 3. Institute of theoretical physics Chinese Academy of Sciences 100080 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.