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Quantitative estimation of the shrub canopy LAI from atmosphere-corrected HJ-1 CCD data in Mu Us sandland

science china earth sciences 2010年第S1期53卷 26-33页

作者： CHEN Wei1,2,CAO ChunXiang1,HE Qisheng1,2,GUO HuaDong3.ZHANG Hao1,2,LI RenQiang4,ZHENG sheng1,2,XU Min1,2,GAO MengXu1,2,ZHAO Jian1,2,LI sha1,NI XiLiang1,2,JIA HuiCong1,JI Wei1,TIAN Rong1,2,LIU Cheng1,2,ZHAO YuXing5 & LI JingLu6 1 state Key Laboratory of Remote sensing science,Jointly sponsored by the Institute of Remote sensing Applications of Chinese Academy of sciences and beijing Normal university,beijing 100101,{3. 2 Graduate university of Chinese Academy of sciences,beijing 100049,{3. 3.Center for earth Observation and Digital earth,Chinese Academy of sciences,beijing 100190,{3. 4 {3. Key Laboratory of Ecological Network Observation and Modeling,Institute of geographical sciences and Natural {13. Research,Chinese Academy of sciences,beijing 100101,{3. 5 Ordos Forestry sand Control science Institute,Dongsheng 017000,{3. 6 Inner Mongolia Biomass Thermoelectricity Limited Company,Wushen 0173.0,{3. 1. state Key Laboratory of Remote sensing science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China 2. Graduate university of Chinese Academy of sciences Beijing 100049 China 3. Center for earth Observation and Digital earth Chinese Academy of Sciences Beijing 100190 China 4. china Key Laboratory of Ecological Network Observation and Modeling Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China 5. Ordos Forestry sand Control science Institute Dongsheng 017000 China 6. Inner Mongolia Biomass Thermoelectricity Limited Company Wushen 017300 China

The leaf area index(LAI) is an important ecological parameter that characterizes the interface between vegetation canopy and the *** addition,it is used by most process-oriented ecosystem *** paper investigates the potential of HJ-1 CCD data combined with linear spectral unmixing and an inverted geometric-optical model for the retrieval of the shrub LAI in Wushen Banner of Inner Mongolia in the Mu Us ***(Moderate Resolution Atmospheric Radiance and Transmittance Model) was used for atmospheric *** was extracted using the threshold of the normalized difference vegetation index,with which water bodies and farmland were separated,in combination with a vegetation map of the People's Republic of china(1:1000000).Using the geometric-optical model,we derive the per-pixel reflectance as a simple linear combination of two components,namely sunlit background and *** fraction of sunlit background is related to the shrub *** the support of HJ-1 CCD data,we employ linear spectral unmixing to obtain the fraction of sunlit background in an atmospherically corrected HJ *** addition,we use the measured shrub canopy structural parameters for shrub communities to invert the geometric-optical model and retrieve the pixel-based shrub *** total,18 sample plots collected in Wushen Banner of Inner Mongolia are used for *** results of the shrub LAI show good agreement with R2 of 0.817 and a root-mean-squared error of 0.173.

关键词： shrub leaf area index inversion HJ-1 data geometric-optical model MODTRAN Mu Us sandland

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Corrosion Fatigue Behavior of Duplex stainless steel in 3.5% sodium Chloride solution

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Journal of university of science and Technology beijing 2001年第2期8卷 133-136页

作者： s. H Abubakir, Yinshun Wu, Baofeng Ding, Jiuqing Li Bei Cao (Material science and Engineering school, university of science and Technology beijing,{3.) Univ sci & Technol beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China

The corrosion fatigue behavior of duplex stainless steel (Dss) was studied at different cyclic stress levels in 3.5%NaCl (mass fraction, so as the follows) solution (pH=7) at 50 degreesC. The results showed that Dss was susceptible to pitting corrosion and corrosion fatigue. Both intergranluar corrosion cracking and transgranlular corrosion cracking initiated at the bottom of pitting holes. Furthermore, the corrosion fatigue properties of Dss in 3.5%NaCl solution may be relatived to complex electrochemical and mechanical coupling effects between the three phases (austenite, ferrite and martensite), where martensite and ferrite were anodic in the corrosion cell and could be prone to cracking under certain condition.

关键词： corrosion fatigue duplex stainless steel sodium chloride solution

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sequence stratigraphy and depositional systems in the Paleogene,Liaodong Bay

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Petroleum science 2008年第2期5卷 110-118页

作者： Ji Hancheng school of resources and Information Technology China University of Petroleum Beijing 102249 China

Based on drilling and seismic data, the Paleogene developed in Liaodong Bay can be divided into five third-order sequences bounded by six sequence boundaries. Through analyzing depositional systems in each sequence in detail, the Es-3.time was defined as fast rifting. During the deposition of the Es-3.member, the lake basin was continuous along the N-s direction but compartmentalized along the E-W direction by several N-s trending faults. Deposition was dominated by steep slope fans and fan deltas. The time of Es-2 and Es-1 was stable settling. The lake basin expanded substantially. The fan delta system and braided fluvial system were developed. Carbonate and clastic deposits were formed on the Liaoxi （west Liaohe） Rise. The time of Ed-3.time was again fast rifting. During this time, shale was deposited. In the time of Es-2, tectonic movement weakened. The basin was higher in the west and north, and lower in the east and south. A series of delta depositional systems were developed and smallscale slumping turbidite fans were present in semi-deep lake to deep lake. In the time of Ed-1, tectonic movement stopped. Flood plain deposition occurred. Finally the paper presents the characteristics of evolution and distribution of depositional systems both vertically and horizontally.

关键词： Liaodong Bay Paleogene sequence depositional system

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Molecular mechanism of dehydrin in response to environmental stress in plant

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Progress in Natural science:Materials International 2007年第3期17卷 237-246页

作者： ZHANG Yuxiu , WANG Zi and XU Jin (Department of Bioengineering, school of Chemical and Environmental Engineering, china university of Mining and Technology ({3.), beijing 100083. china Department of Biology, Graduate university of Chinese Academy of sciences, {3. 100049, china) [a]Department of Bioengineering School of Chemical and Environmental Engineering China University of Mining and Technology (Beiing) Beijing China [b]Department of Biology Graduate University of Chinese Academy of Sciences Beijing China

Dehydrins, known as the D-11 subgroup of late embryogenesis abundant (LEA) protein, are an immunologically distinct family of proteins, which typically accumulate in desiccation-tolerant seed embryo or in vegetative tissues in response to various environmental stresses such as drought, salinity and freezing. The existence of conservative sequences designated as K, s, and Y segments is a structural feature of dehydrins, and the K segment found in all dehydrins represents a highly conserved 15 amino acid motif (EKKGIMDKIKEKLPG) and forms an amphiphilicα-helix. According to the arrangement of these domains and clustering analysis, dehydrins are subdivided into 5 subtypes: YnsK, Kn, Kns, sKn and YnK. Different types of dehydrins are induced by different environmental stress in plants. study results showed that dehydrins might play important protective roles under abiotic stress via a number of different mechanisms, including improving or protecting enzyme activities by the cryoprotective activity in responding to freeze/thaw or dehydration; stabilizing vesicles or other endomembrane structures by function as the membrane stabilizer during freeze induced dehydration, and preventing the membrane system from the oxidative damage induced by reactive oxygen radicals as the radical scavenger. Here, the gene expression and molecular mechanisms of dehydrin in response to stress in plants are discussed.

关键词： dehydrin stress mechanism.

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Numerical study on spatially varying control parameters of a marine ecosystem dynamical model with adjoint method

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Acta Oceanologica sinica 2011年第1期30卷 7-14页

作者： QI Ping WANG Chunhui LI Xiaoyan LV Xianqing school of Environment Beijing Normal University Beijing 100875 China Laboratory of Physical Oceanography Ocean University of China Qingdao 266100 China

Based on the simulation of a marine ecosystem dynamical model in the Bohai sea, the Yellow sea and the East china sea, chlorophyll data are assimilated to study the spatially varying control parameters （CPs） by using the adjoint method. In this study, the CPs at some grid points are selected as the independent CPs, while the CPs at other grid points can be obtained through linear interpolation with the independent CPs. The independent CPs are uniformly selected from each 3.′ × 3.′area, and we confirm that the optimal influence radius is 1.2° by a twin experiment. In the following experiments, when only the maximum growth rate of phytoplankton （Vm） is estimated by two given types of spatially varying CPs, the mean relative errors of Vm are 1.22% and 0.94% while the decrease rates of the mean error of chlorophyll in the surface are 94.6% and 95.8%, respectively. When the other four CPs are estimated respectively, the results are also satisfactory, which indicates that the adjoint method has a strong ability of optimizing the prescribed CP with spatial variations. However, when all these five most important CPs are estimated simultaneously, the collocation of the changing trend of each parameter influences the estimation results remarkably. Only when the collocation of the changing trend of each parameter is consistent with the ecological mechanisms which influence the growth of the phytoplankton in marine ecosystem, could the five most important CPs be estimated more accurately.

关键词： marine dynamical ecosystem adjoint method influence radius spatially varyingparameters

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Based on the spectral Variation of Vegetation Monitoring the Heavy Metal Pollution of soil

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地学前缘 2009年第S1期16卷 86-87页

作者： Li Mi school of Information Engineering,china university of {3.sciences(beijing),beijing 100083.china.

Heavy metal pollution of soil is one of serious problems of *** easy to break down, heavy metal was enriched and became the pollutants. It would not only destroy the normal function of soil and impede the growth of crops,but also through the food chain cause the harm to human *** the impact of heavy metal pollution of soil,the vegetation is also very easy to be *** the vegetation has been contaminated,its internal structure,

关键词： heavy metal pollution chlorophyll spectral variation red valley parameters

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Retrieving crop leaf area index by assimilation of MODIs data into a crop growth model

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science china earth sciences 2010年第5期53卷 721-730页

作者： WANG DongWei1,2,3. WANG JinDi1,2 & LIANG shunLin4 1 state Key Laboratory of Remote sensing science, Jointly sponsored by beijing Normal university and Institute of Remote sensing Applications, CAs, beijing 100875, {3. 2 school of geography, beijing Key Laboratory of Environmental Remote sensing and Digital City, beijing Normal university, beijing 100875, {3. 3.Haihe River Water Conservancy Commission, Tianjin 3.0170, {3. 4 Department of geography, university of Maryland, College Park, MD 20742, UsA 1. state Key Laboratory of Remote sensing science Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing Applications CAS Beijing 100875 China2. School of Geography Beijing Key Laboratory of Environmental Remote Sensing and Digital City Beijing Normal University Beijing 100875 China3. Haihe River Water Conservancy Commission Tianjin 300170 China4. Department of Geography University of Maryland College Park MD 20742 USA

Leaf area index (LAI) is an important parameter in monitoring crop growth. One of the methods for retrieving LAI from remotely sensed observations is through inversion of canopy reflectance models. Many model inversion methods fail to account for variable LAI values at different crop growth stages. In this research, we use the crop growth model to describe the LAI changes with crop growth, and consider a priori LAI values at different crop growth stages as constraint information. The key approach of this research is to assimilate multiple canopy reflectance values observed at different growth stages and a priori LAI values into a coupled crop growth and radiative transfer model sequentially using a variational data assimilation algorithm. Adjoint method is used to minimize the cost function. Any other information source can be easily incorporated into the inversion cost function. The validation results show that the time series of MODIs canopy reflectance can greatly reduce the uncertainty of the inverted LAI values. Compared with MODIs LAI product at Changping and shunyi Counties of beijing, this method has significantly improved the estimated LAI temporal profile.

关键词： inversion leaf area index crop growth model time series MODIs

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Regional differences and determinants of built-up area expansion in china

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science china earth sciences 2007年第12期50卷 1835-1843页

作者： HUANG JiKun1,2,ZHU LiFen3.1 & DENG XiangZheng1,2 1 Center for Chinese Agricultural Policy,Chinese Academy of sciences,beijing 100101,china 2 Institute of geographic sciences and Natural {3. Research,Chinese Academy of sciences,beijing 100101,china 3.Research Center of the Economy of the Upper Reaches of the Yangtze River,Chongqing Technology and Business university,Chongqing 400067,china 1. Center for Chinese Agricultural Policy Chinese Academy of Sciences Beijing 100101 China 2. Institute of geographic sciences and Natural resources Research Chinese Academy of Sciences Beijing 100101 China 3. Research Center of the Economy of the Upper Reaches of the Yangtze River Chongqing Technology and Business University Chongqing 400067 China

Based on remote sensing data on land use provided by the Chinese Academy of sciences and socio-economic data collected by the authors,this paper analyzes the trends and regional differences in built-up area(BUA) expansion in china from the late 1980s to 2000,and empirically estimates the major determinants of BUA expansion in different regions in 1996―*** 1989―2000,although china's overall BUA expansion accelerated,the trends differed significantly among *** expansion in the central and western regions accelerated significantly,but it slowed down considerably in the east-ern *** estimation results from our econometric analysis reveal that BUA expansion in the eastern region reached a period when economic growth had no further significant impact on per capita BUA,the land utilization in this region has become more intensive with further expansion of the *** the central and western regions,the BUA has expanded remarkably due to the relatively more flexible land development policies and the relatively cheap land ***,as the econ-omy continues to grow rapidly,policies relating to BUA expansion and cultivated land reductions may face more serious challenges in the central and western regions.

关键词： built-up area, land use, regional difference, determinants, china

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N-way blending problem of circular quadrics

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science china(Information sciences) 2010年第8期53卷 1546-1554页

作者： FANG MeiE 1,3., Wang GuoZhao 2 & MA WeiYin 3.1 school of Computer science, Hangzhou Dianzi university, Hangzhou 3.0081, china 2 Department of Mathematics, Zhejiang university, Hangzhou 3.0018, china 3.Department of MEEM, City university of Hong Kong, Hong Kong, china 1. school of Computer science Hangzhou Dianzi University Hangzhou 310081 China3. Department of MEEM City University of Hong Kong Hong Kong China2. Department of Mathematics Zhejiang University Hangzhou 310018 China

A method of blending circular quadrics with parametric patches is proposed in this paper. It needs n rational bi-cubic B′ezier patches and two s-patches to blend n (n > 2) quadrics. Bi-cubic rational B′ezier patches are used to G 1 -continuously blend each pair of adjacent base surfaces. These patches enclose two n-sided holes. And an s-patch is used to fill each hole, which keeps nearly G 1-continuity. Explicit formulas of control points for both B′ezier patches and s-patches are derived from their constraint conditions, which make modeling by blending quadrics very simple and convenient. In addition, the shapes of the blending surfaces can be intuitively adjusted by free parameters.

关键词： circular quadrics blending n-way s-patch

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The evolution model of the earth's limited expanding

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Chinese science Bulletin 2000年第4期45卷 304-313页

作者： CHEN Zhigengchina university of Mining and Technology, beijing 100083. china china university of Mining and Technology Beijing China

Based on the prerequisite that the earliest acid rock formed because of the initial global expanding tectonic processes, by combining it with other geological limitation conditions, and starting from the lithosphere elastic mechanics, the following is defined : the earth expansion started at about 43.0 Ma ago, the average increasing rate of the earth radius is 0.40 mm/a, the initial expanding earth radius is 4651 km, and the initial global expansion of tectonic processes happened at 4183.7 Ma ago. From the natural and attenuation evolution condition of the earth and terrestrial planets, through the limit condition got from the combination of the mathematics logic and the geological significance, the limited expanding earth evolution model is established as follows:in which R0= 4.651×106 m, A =1.86×106 m, β = -6.01?10-10 a and ts=3.10 a. From this model the maximum radius Rmax of the limited expanding earth evolution should be 6511 km. The earth’s radius increasing rate is about 0.1 mm/a at present.

关键词： limited earth expansion evolution model start time of expansion start time of expanding tectonism stage character of tectonism .

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