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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.

Multiple time scale evaluation of the energy balance during the maize growing season,and a new reason for energy imbalance

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Science China Earth Sciences 2009年第1期52卷 108-117页

作者： GUO JianXia1,2,BIAN LinGen3 & DAI YongJiu2 1 Meteorological Observation center of China Meteorological Administration,Beijing 100081,China 2 State Key laboratory of Remote Sensing Science,School of Geography and Remote Sensing Science,Beijing Normal University,Beijing 100875,China 3 Chinese Academy of Meteorological Sciences,Beijing 100081,China Meteorological Observation center of China Meteorological Administration Beijing China State Key laboratory of Remote Sensing Science School of Geography and Remote Sensing Science Beijing Normal University Beijing China Chinese Academy of Meteorological Sciences Beijing China

Energy imbalance is a common problem associated with the measurement of surface energy using the eddy covariance *** the evaluation of the energy balance,people usually pay more attention to the statistical result that the effective energy(the sum of sensible and latent heat) is systematically lower than the available energy(the difference of net radiation and ground heat flux).However,little attention has been paid to the existence of the reversed situation when the effective energy is larger than the available energy or their contribution to the overall energy closure *** this paper,based on the analysis of the energy balance on multiple time scales across the maize growth season,we conclude that the non-synchronization of energy components is the main reason for the existence of the reversed *** shifting the phase of the effective energy components half an hour ahead,the rates of energy closure over all time scales are improved and dramatically reduce the number of the half-hourly samples when the energy ratio exceeds 1 or is below *** to the characteristics of the energy distribution and transformation over multiple time scales,latent heat is always the main type of energy cost,and the residual of the energy balance increases with the growth of the maize plant surpassing the sensible heat for seventy *** is suggested that the heat storage and photosynthetic energy play an important role in the energy balance during the growing period of maize.

关键词： maize energy balance multiple time scale energy hysteresis

Cesium accumulation by bacterium Thermus sp. TibetanG7:hints for biomineralization of cesium-bearing geyserite in hot springs in Tibet,China

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Chinese Science Bulletin 2007年第19期52卷 2680-2686页

作者： WANG HaiLei1,2,3, ZHENG MianPing1,2,3 & HUANG XiaoXing4 1 Institute of Mineral Resources, Chinese Academy of Geological Sciences (CAGS), Beijing 100037, China 2 R&D center for Saline Lake and Epithermal Deposits, CAGS, Beijing 100037, China 3 Open laboratory of Saline Lake Resourses and Environment, CAGS, Beijing 100037, China 4 laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100081, China Institute of Mineral Resources Chinese Academy of Geological Sciences (CAGS) Beijing China R&D center for Saline Lake and Epithermal Deposits CAGS Beijing China Open laboratory of Saline Lake Resourses and Environment CAGS Beijing China laboratory of Microbial Resources Institute of Microbiology Chinese Academy of Sciences Beijing China

The bacterium Thermus sp. TibetanG7, isolated from hot springs in Tibet, China, was examined for the ability to accumulate cesium from solutions. Environmental conditions were simulated and the effects of pH, K+, Na+ and K+-regimes were then studied to determine the possible role of the bacterium in the formation of cesium-bearing geyserite around these hot springs. In despite of the inhibition of K+ and Na+, the bacterium Thermus sp. TibetanG7 revealed noticeable accumulation of cesium from solutions, with maximum accumulations of 53.49 and 40.41 μmol Cesium/g cell dry weight in Na+ and K+ inhibition experiments, respectively. The accumulation of cesium by this microorganism is rapid, with 40%―50% accumulated within the first 5 min. K+-deficient cells showed a much higher capacity of cesium accu- mulation compared with K+-sufficient cells. It is evident that the bacteria within the genus thermus play a significant role in the cesium assembly. The formation of cesium-bearing geyserite is also considered.

关键词：铯元素沉积物硅华生物矿化

High-pressure synthesis and properties of CeO_2-ZrO_2 solid solution

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Chinese Science Bulletin 2001年第10期46卷 801-806页

作者： XU Dapeng, WANG Quanyong, LU Zhe, LIU Zhiguo, ZHANG Gongmu & SU Wenhui1. Department of Physics, Jilin University, Changchun 130023 China 2. International center for Materials Physics, Chinese Academy of Sciences, Shenyang 110015, China 3. center for Condensed Matter and Radiation Physics, China center of Advanced Science and Technology (World laboratory), Beijing 100080, China Department of Physics Jilin University Changchun China International center for Materials Physics Chinese Academy of Sciences Shenyang China center for Condensed Matter and Radiation Physics China Center of Advanced Science and Technology (World Laboratory) Beijing China

Using nanoparticles of CeO2 and ZrO2 prepared by the chemical precipitation method as starting materials, the single-phase cubic Ce0.5Zr0.5O2 solid solution (c-Ce0.5Z0.5O2) has been synthesized under 3.1 GPa at 1073 K for the first time. The structure of the c-Ce0.5Zr0.5O2 has not been changed before and after annealing at 773 K for 1 h. Only an unknown EPR signal (g =1.990) has been observed in the c-Ce0.5Zr0.5O2 and not varied after annealing at 773 K for 1 h, which exhibited that there exists no Ce3+ in the c-Ce0.5Zr0.5O2 and the Ce4+ has not been reduced into Ce3+ after annealing. The transport mechanism is ionic for the c-Ce0.5Zr0.5O2. The bulk conductivity (a =1.2×10-5 S/cm at 823 K, σ=2.1 ×10-3 S/cm at 1123 K) is the same as that of CeO2, but smaller than that of Y2O3-stabilized ZrO2. A marked curvature at T = 823 K has been observed in the Arrhenius plot of the bulk conductivity. The activation energy below 823 K is lower than that above 823 K, and the reason has been discussed.

关键词： CeO2-ZrO2 nanocrystalline high-pressure and -temperature solid-state reaction solid solution.

The coupling instability of Rossby and topographic Rossby waves in the equatorial area

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Science China Earth Sciences 2005年第10期48卷 1792-1801页

作者： CHAO Jiping1,2, LIU Lin1,3 & YU Weidong1 1. laboratory of Marine Science and Numerical Modeling, State Oceanic Administration, Qingdao 266061, China 2. National Research center for Marine Environmental Forecasts, State Oceanic Administration, Beijing 100081, China 3. Ocean University of China, Qingdao 266003, China State Oceanic Administration Ocean University of China

In case of considering the fact that the tropical ocean thermocline or the lower at-mosphere height field has the meridional variation, the topographic Rossby wave will be excited. Also the background geostrophic current emerges. Under such conditions, the topographic Rossby wave can interact with the classical Rossby wave at some parameter band and thus brings a new kind of instability, which may be of potential application in understanding some phenomena of the ENSO cycle.

关键词： thermocline variation, equatorial jet, Rossby wave, topographic Rossby wave, coupling instability

A new approach toward object-based change detection

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Science China(Technological Sciences) 2010年第S1期53卷 105-110页

作者： ZHANG Guo1,2,LI Yang1 & LI ZhiJiang3 1 State Key laboratory of Information Engineering in Surveying,Mapping and Remote Sensing,Wuhan University,Wuhan 430079,China 2 Satellite of Surveying and Mapping Application center,State Bureau of Surveying and Mapping,Beijing 100830,China 3 School of Printing and Packaging,Wuhan University,Wuhan 430079,China State Key laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan China Satellite of Surveying and Mapping Application center State Bureau of Surveying and Mapping Beijing China School of Printing and Packaging Wuhan University Wuhan China

Object-based change detection has been the hotspot in remote sensing image processing.A new approach toward object-based change detection is *** two different temporal images are unitedly segmented using the mean shift procedure to obtain corresponding *** change detection is implemented based on the integration of corresponding objects’ intensity and texture *** are conducted on both panchromatic images and multispectral images and the results show that the integrated measure is robust with respect to illumination changes and *** color detection is conducted to determine whether the color of the unchanged objects changes or not when dealing with multispectral *** verification work is carried out to show the accuracy of the proposed approach.

关键词： mean shift united segmentation change detection object-based intensity texture integration

Propagation of interplanetary shock excited ultra low frequency (ULF) waves in magnetosphere-ionosphere-atmosphere——Multi-spacecraft “Cluster” and ground-based magnetometer observations

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Science China(Technological Sciences) 2010年第9期53卷 2528-2534页

作者： WANG ChengRui1,2,ZONG QiuGang1,3 & WANG YongFu1 1 Institute of Space Physics and Applied Technology,Peking University,Beijing 100871,China 2 Sate Key laboratory of Space Weather,Chinese Academy of Sciences,Beijing 100190,China 3 center for Atmospheric Research,600 Suffolk Street,University of Massachusetts Lowell,MA 01854,USA Institute of Space Physics and Applied Technology Peking University Beijing China Sate Key laboratory of Space Weather Chinese Academy of Sciences Beijing China center for Atmospheric Research University of Massachusetts Lowell USA

The ultra low frequency (ULF) wave in magnetosphere can act as an important means for solar wind energy inward *** paper quantitatively analyzes the propagation process of the ULF wave triggered by the interplanetary shock propagating from inner magnetosphere equatorial plane along magnetic field lines to the top of the ionosphere and below ionosphere propagating process and establishes a relatively complete magnetosphere-ionosphere-atmosphere propagation model which can be used to study the relationship between the amplitude of the ULF waves triggered by the interplanetary shock wave in magnetospheric space and the magnetic effect caused by the ULF *** a comparison with recent observations,we found that: in the event during November 7,2004 that an interplanetary shock wave interacted with the magnetosphere,Cluster satellites observed that electric field fluctuations and the band-pass filtered result of ground stations meridional component had similar *** with the geomagnetic measurement near the footprints,we found that the electric field disturbance in the magnetosphere spread along the ground magnetic field lines in the form of the ULF waves and changed into geomagnetic *** result reveals that the ULF wave is in contact with the ground geomagnetic *** ULF waves couple with ionized components in ionosphere and spread to the ground in the form of electromagnetic *** this research,we believe that the magnetosphere,ionosphere and ground magnetic effects caused by interplanetary shock wave are the same physical phenomena responding in different *** on the overall consideration of entire electromagnetic response to the interplanetary shock wave,we found that the correlation between CLUSTER multi-satellite observation and geomagnetic station observation is due to the ULF wave propagated in magnetosphere-ionosphere-atmosphere system,and we quantitatively interpreted this response process

关键词： ultra low frequency (ULF) wave magnetic storm ionosphere IRI model interplanetary shock

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 laboratory Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, 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.

Large-eddy simulation of formation of three-dimensional aeolian sand ripples in a turbulent field

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Science China(Physics,Mechanics & Astronomy) 2008年第8期51卷 945-960页

作者： WU ChuiJie1,WANG Ming2 & WANG Liang3 1 State Key laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,Dalian 116024,China 2 Yellow River Institute of Hydraulic Research,Zhengzhou 450003,China 3 Research center for Fluid Dynamics,Science School,PLA University of Science and Technology,Nanjing 211101,China State Key laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian China Yellow River Institute of Hydraulic Research Zhengzhou China Research center for Fluid Dynamics Science School PLA University of Science and Technology Nanjing China

With the method of large-eddy simulation,the equation of spherule motion and the method of immersed boundary condition,numerical simulations of three-dimen-sional turbulent aeolian motion and the formation of sand ripples under three-di-mensional turbulent wind and the mutual actions of saltation and creeping motion were carried out. The resulting sand ripples have the form that is flat on the upwind side and steep on the leeward,which is identical to the sand ripples in nature. We also realized the self-restoration process of three-dimensional sand ripples,which shows the correctness of the method of numerical simulation and the models of saltation and creeping. Finally,We analyzed the influence of sand ripples on the three-dimensional turbulent wind field,and found that due to the appearance and development of sand ripples,in the normal direction of ground there exists stronger energy exchange,and moreover,there is close correspondence between the forms of sand ripples and the vorticity close to the ground surface.

关键词： large-eddy simulation equation of spherule motion sand ripples saltation creep