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Analysis of leakage current in GaAs micro-solar cell arrays

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science china(Technological sciences) 2010年第5期53卷 1240-1246页

作者： WANG YanShuo1,CHEN NuoFu1,2,3,ZHANG XingWang1,BAI YiMing1,WANG Yu1,HUANG TianMao1,ZHANG Han1 & SHI HuiWei1 1 Key Laboratory of Semiconductor Materials science,institute of Semiconductors,chinese academy of sciences,PO Box 912,beijing 100083,china 2 school of Renewable Energy Engineering,North china Electric Power University,beijing 102206,china 3 National Laboratory of Micro-Gravity,institute of Mechanics,chinese academy of sciences,beijing 100080,china 1. Key Laboratory of Semiconductor Materials science Institute of Semiconductors Chinese Academy of Sciences PO Box 912 Beijing 100083 China2. School of Renewable Energy Engineering North China Electric Power University Beijing 102206 China3. National Laboratory of Micro-Gravity Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

The output characteristics of micro-solar cell arrays are analyzed on the basis of a modified model in which the shunt resistance between cell lines results in current *** modification mainly consists of adding a shunt resistor network to the traditional *** obtained results agree well with the reported experimental *** calculation results demonstrate that leakage current in substrate affects seriously the performance of GaAs micro-solar cell *** performance of arrays can be improved by reducing the number of cells per *** addition,at a certain level of integration,an appropriate space occupancy rate of the single cell is recommended for ensuring high open circuit voltages,and it is more appropriate to set the rates at 80%-90% through the calculation.

关键词： micro-solar cell MEMS(micro-electromechanical systems) leakage current

Virus rejection with two model human enteric viruses in membrane bioreactor system

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science china Chemistry 2007年第3期50卷 397-404页

作者： ZHENG Xiang1,2 & LIU JunXin1 1 Research Center for Eco-Environmental sciences, chinese academy of sciences, beijing 100085, china 2 school of Environment & Natural Resources, Renmin University of china, beijing 100872, china 1. Research Center for Eco-Environmental sciences Chinese Academy of Sciences Beijing 100085 China 2. school of Environment & Natural Resources Renmin University of China Beijing 100872 China

A membrane bioreactor (MBR) with gravity drain was tested for virus rejection with two coliphages, T4 and f2, which were used as surrogates for human enteric viruses. Virus rejection was investigated by PVDF and PP membrane modules, with the pore sizes of 0.22 and 0.1 μm, respectively. In tap water system, 2.1 lg rejection of coliphage T4 could be achieved by PVDF membrane compared with complete rejection by PP membrane, while for coliphage f2 with smaller diameter, 0.3―0.5 lg rejection of the influent virus was removed by the two membranes. In domestic wastewater system, cake layer and gel layer on the membrane surface changed the cut-off size of the membrane so that there was no significant difference between PP and PVDF for each coliphage. The removal ratios of coliphage T4 and f2 in the MBR were more than 5.5 and 3.0 lg, respectively. Compared with 5.5 lg removal for virus T4 in the MBR system, only 2.1 lg (96.8%―99.9%) removal rate was observed in the conventional activated sludge system with the influent virus concentration fluctuating from 1830 to 57000 PFU/mL. Only 0.8%―22% virus removal was the effect of adsorption to activated sludge, which showed a decreasing tendency with the retention time, while 75%―98% was the effect of virus inactivation by microbial activity. It indicated that the major mechanism of virus removal was not the transfer of viruses from the water phase to the sludge phase but inactivation in the biological treatment process.

关键词： MBR model virus enteric virus inactivation

Maximum Principle for the Optimal Control of an Ablation-Transpiration Cooling system with Free Final Time

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Maximum Principle for the Optimal Control of an Ablation-Tra...

Spatial heterogeneity of the driving forces of cropland change in china

第二十四届中国控制会议

作者： bing sun~(1,2), baozhu guo~1 ~1institute of systems science, academy of mathematics and system sciences, academia sinica, beijing 100080, china ~2graduate school of the chinese academy of sciences, beijing 100049, china

＜正＞ This paper is concerned with the optimal control problem of an ablation-transpiration cooling control system with Stefan-Signorini boundary condition. The Pontryagin’s maximum principle of the system is presen... 详细信息

关键词： Ablation-transpiration Stefan-Signorini problem optimal control(OC) Pontryagin’s maximum principle Dubovitskii-Milyutin approach.

来源： cnki会议评论

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science china Earth sciences 2005年第12期48卷 2231-2240页

作者： LIU Xuhua1,2, WANG Jinfeng1, LIU Mingliang4,1 & MENG Bin1,2,3 1. institute of Geographic sciences and Natural Resources Research, chinese academy of sciences, beijing 100101, china 2. graduate school of the chinese academy of sciences, beijing 100039, china 3. College of Arts and sciences of beijing Union University, beijing 100083, china 4. school of Forestry and Wildlife sciences, Auburn University, Auburn, Alabama, AL36849, USA 1. institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. graduate school of the chinese academy of sciences 100039 Beijing China 3. school of Forestry and Wildlife sciences Auburn University Auburn AL36849 Alabama USA 4. College of Arts and sciences of beijing Union University 100083 Beijing China

By using digital satellite remote sensing data acquired in 1987―1989 and 1999―2000 and GIS combined with the natural and socio-economic data, this paper drew an integrated zonation of the cropland change and its driving forces in china. The results indicated that the cropland change in the study period was constrained by geographical factors and driven by cli-mate change as well as socio-economic system. Moreover, the regional differences of the drivers for cropland change were significant. In the midwest of china, natural condition changes and geographical background were the main constraints and drivers, while in Eastern china, social and economic changes and economic policies were the main driving forces. The cropland loss was nationwide. The dominant factors to cause this decrease included buildup of developing area to attract foreign capital and technologies, changes of industry structure due to urban in-fluence, the change of employment notions thanks to living standard improvement, rapid ur-banization due to the expansion of cities and towns, the diminished farming net income partly because of the global warming effects, and the rapid economic growth stimulated by the con-venient transportation system. These factors interact and interdepend with each other to cause the cropland loss in china recently. The reasons for the increase of cropland were primarily the cultivation and deforestation by the farmers who want to increase income. This study on the mechnism of LUCC relied on the cropland change integrated classification considering the natural or human factors both inside and outside the region, which provides a new approach to study the integrated regionalization and LUCC mechanism.

关键词： land use change, driving force, integrated classification, spatial statistics, cropland, china.

CONVERGENCE OF (0,1,2,3) INTERPOLATION ON AN ARBITRARY system OF NODES

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Journal of Computational mathematics 2001年第2期19卷 151-156页

作者： Ying-guang Shi (institute of Computation, Hunan Normal University, Changsha 410081, china) (institute of Computational mathematics and Scientific/Engineering Computing, academy of mathematics and systems sciences, chinese academy of sciences, beijing 100 湖南师范大学湖南长沙 410081

Provides information on a study which simplified and improved convergence of (0,1,2,3) interpolation on an arbitrary system of nodes. Definitions and notations; Results; Conjectures.

关键词： Hermite interpolation Hermite-Fejer interpolation convergence

Design of secure operating systems with high security levels

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science in china(Series F) 2007年第3期50卷 399-418页

作者： QING SiHan1,2 & SHEN ChangXiang3 1 institute of Software, chinese academy of sciences, beijing 100080, china 2 school of Software and Microelectronics, Peking University, beijing 102600, china 3 institute of Computing Technology, Navy, beijing 100841, china 1. institute of Software Chinese Academy of Sciences Beijing 100080 China 2. school of Software and Microelectronics Peking University Beijing 102600 China 3. institute of Computing Technology Navy Beijing 100841 China

Numerous Internet security incidents have shown that support from secure operating systems is paramount to fighting threats posed by modern computing environments. Based on the requirements of the relevant national and international standards and criteria, in combination with our experience in the design and development of the ANSHENG v4.0 secure operating system with high security level （hereafter simply referred to as ANSHENG OS）, this paper addresses the following key issues in the design of secure operating systems with high security levels： security architecture, security policy models, and covert channel analysis. The design principles of security architecture and three basic security models： confidentiality, integrity, and privilege control models are discussed, respectively. Three novel security models and new security architecture are proposed. The prominent features of these proposals, as well as their applications to the ANSHENG OS, are elaborated. Cover channel analysis （CCA） is a well-known hard problem in the design of secure operating systems with high security levels since to date it lacks a sound theoretical basis and systematic analysis approach. In order to resolve the fundamental difficulties of CCA, we have set up a sound theoretical basis for completeness of covert channel identification and have proposed a unified framework for covert channel identification and an efficient backward tracking search method. The successful application of our new proposals to the ANSHENG OS has shown that it can help ease and speedup the entire CCA process.

关键词： secure operating systems with high security levels architecture security model covert channel analysis

ON COMPLEX DYNAMIC CONTROL systems

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Journal of systems science & Complexity 2003年第3期16卷 350-357页

作者： CHENG Daizhan (institute of systems science, chinese academy of sciences, beijing 100080, china) institute of systems science Chinese Academy of Sciences 北京 100080

This paper presents some recent works on the control of dynamic systems,which have certain complex properties caused by singularity of the nonlinear structures,structure^varyings, or evolution process etc. First, we consider the structure singularity of nonlinear control systems. It was revealed that the focus of researches on nonlinear control theory is shifting from regular systems to singular systems. The singularity of nonlinear systems causes certain complexity. Secondly, the switched systems are considered. For such systems the complexity is caused by the structure varying. We show that the switched systems have significant characteristics of complex systems. Finally, we investigate the evolution systems. The evolution structure makes complexity, and itself is a proper model for complex systems.

关键词： relative degree byrnes-isidori normal form center manifold switchedsystems evolution system

Land cover changes based on plant successions: Deforestation, rehabilitation and degeneration of forest in the upper Dadu River watershed

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science china Earth sciences 2005年第12期48卷 2214-2230页

作者： YAN Jianzhong1,2,3, ZHANG Yili1, BAI Wanqi1, LIU Yanhua4, BAO Weikai5, LIU Linshan1, 2 & ZHENG Du1 1. institute of Geographic sciences and Natural Resources Research, chinese academy of sciences, beijing 100101, china 2. graduate school of the chinese academy of sciences, beijing 100039, china 3. College of Resources and Environment, Southwest Agricultural University, Chongqing 400716, china 4. The Ministry of science and Technology, P. C. china, beijing 100862, china 5. Chengdu institute of Biology, chinese academy of sciences, Chengdu 610041, china 1. institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. graduate school of the chinese academy of sciences 100039 Beijing China 3. College of Resources and Environment Southwest Agricultural University 400716 Chongqing China 4. The Ministry of science and Technology P. C. China 100862 Beijing China 5. Chengdu institute of Biology Chinese Academy of Sciences 610041 Chengdu China

To link regional land use/cover changes with environmental effects, land cover changes are required to reflect vegetation successions, whereas the land cover classification systems commonly used nowadays cannot serve this purpose. In this paper, a new land cover classification system is established in which land covers are classified by the vegetation succes-sions, taking Zamtang County, Barkam County and Jinchuan County in the upper Dadu River watershed as a study area. Using multi-temporal remote sensing images, the land cover data of 1967, 1986 and 2000 are obtained by means of integration of unsupervised classification and visual interpretation methods. The database facilitates the study of land use/cover changes, en-vironmental effects and ecological construction. Land cover changes reflect the main ecological processes in the upper Dadu River watershed. The landscape composed mainly of grasslands, wildwoods and alpine scrubs in 1967 was changed to that of grasslands, secondary forests, al-pine scrubs, fragmentary wildwoods, artificial forests, secondary scrubs in 2000, meanwhile, the landscape got more fragmentized. The total area of the forests decreased by 9.43%. Study results have shown the process of restoration of logged areas in forest centers. From 1967 to 2000, only 6.86 percents of logged areas were converted to shrubs, meadows or crop-lands, and the rest were converted into artificial forests or secondary forests. So the ecological shelter functions will be restored, stage by stage. Firewood collection, charcoal production and overgrazing are the three major triggers for the extensive degradation of alpine oak forests, Sa-bina tibetica forests and meadows. The arid valley grasslands expanded too. The degradation of vegetation in the southern slopes impairs ecological shelter functions and affects livelihood of local residents, so it is essential to find effective measures for ecological restoration and recon-struction. Field investigations have found

关键词： land use/cover classification, upper Dadu River watershed, vegetation successions, GIS, RS.

Absolute Stability of General Lurie Control systems with Multi-Nonlinear Feedback Terms

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Acta Mathematica sinica,English Series 2001年第4期17卷 649-656页

作者： Zuo Xin GAN Wei Gao GE institute of systems science, chinese academy of sciences, beijing 100080, P. R. china Department of Applied mathematics, beijing institute of Technology, beijing 100081, P. R. china institute of systems science Chinese Academy of Sciences Beijing 100080 P. R. China Department of Applied mathematics Beijing Institute of Technology Beijing 100081 P. R. China

In this paper, the problenl of absohlte stability for general Lurie control systems with multi- nonlinear feedback terms is investigated. From the Lyapunov function approach. new necessary and sufficient conditious and some practical sufficient conditions of absolute stability are derived. which improve the absolute stability for the set. A numerical examplc illustrates the effectiveness of the proposed results.

关键词： General Lurie system Multi-nonlinear feedback Absolute stability