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Response of remotely sensed Normalized Difference water Deviation Index to the 2006 Drought of eastern Sichuan Basin

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Science china Earth Sciences 2008年第5期51卷 748-758页

作者： ZHANG WenJiang1, LU QiFeng2, GAO ZhiQiang3 & PENG Jian4 1 School of water Resource and Hydropower, Sichuan University, Chengdu 610065, china 2 National Satellite Meteorological Center, china Meteorological Administration, Beijing 100081, china 3 institute of Geographic Sciences and Natural Resources research, Chinese Academy of Sciences, Beijing 100101, china 4 School of Environmental Sciences, Peking University, Beijing 100871, china 1. School of water Resource and Hydropower Sichuan University Chengdu 610065 China 2. National Statellite Meteorological Center China Meteorological Administration Beijing 100081 China 3. institute of Geographic Sciences and Natural Resources research Chinese Academy of Sciences Beijing 100101 China 4. School of Environmental Sciences Peking University Beijing 100871 China

One of the most serious droughts in last century occurred in eastern Sichuan Basin in the summer of 2006 (hereinafter called the Drought). The response of Moderate Resolution Imaging Spectroradiometer (MODIS, boarding on NASA satellites of Terra and Aqua) to the Drought was analyzed in order to reach one practicable monitoring solution for regional soil moisture. Temporal process and spatial extension of the Drought were firstly estimated with ground meteorological and hydrological observations. Then, for the whole region of Sichuan and Chongqing, the remotely sensed Normalized Difference water In- dex (NDWI) for the summers of 2001―2006 were calculated based on 8-day composite MODIS products, which were further used to construct a new water index (Normalized Difference water Deviation Index, NDWDI) to examine the sensitivity of remote sensing in the Drought. The study showed that the NDWDI is more sensitive to regional drought than other absolute-soil-moisture-based indices. With the new index, the study extracted the spatial-temporal characteristics of the 2006 Drought, and explored its developing and withdrawing processes, which agreed with related statistics. Compared with ground method of drought observation, the NDWDI-based remote sensing solution of this paper is more pref- erable and practicable in that the local soil properties of water consumption and supply are implicitly taken into account, and the spatial representativity limit of ground observation is circumvented to a degree as satellite remotely senses the earth surface in a way of two-dimensional pixel matrix. So, the NDWDI-based method can be used to monitor regional soil water stress situation more practically and efficiently.

关键词： Sichuan Basin drought Normalized Difference water Deviation Index response of remote sensing regional scale

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之江文化中心

建筑实践 2024年第4期 140-141页

作者： Zhejiang Prov.institute of Architectural Design and research Architecture-Studio 浙江省建筑设计研究院法国AS建筑工作室

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Simulated multi-scale watershed runoff and sediment production based on GeoWEPP model

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International Journal of Sediment research 2009年第4期24卷 465-478页

The runoff and sediment yield data from the Qiaozidonggou, Qiaozixigou, and Lu’ergou watersheds, in the Loess Plateau of china are used to calibrate and validate the runoff and sediment yield simulated by GeoWEPP model of the WEPP Model at watershed scale. The indices of relative error, R, correlation coefficient, R 2 , and Nash-Suttcliffe efficiency coefficient En s are used to evaluate the model fit. The eco-hydrological responses in the Luoyugou and Lu’ergou watersheds are also forecast based on the WEPP Model. Meanwhile, the relation between vegetation pattern changes and sediment yield in the watershed is discussed, and the responses of runoff and sediment yield in the watersheds concerning forest growth stages are studied. The results show that the relative errors of simulated values of runoff and sediment yield are below 30%, the correlation coefficients are above 0.90, and the Nash-Suttcliffe efficiency coefficients are above 0.80. The simulation results present satisfactory performance, thus, the model could be used to simulate the runoff and sediment yield in these small watersheds. It is also observed that soil erosion tended to become severe as precipitation increased in the watershed, while soil erosion has a decreasing trend as forest cover increases and vegetation pattern is optimized. When the watershed is fully covered by forest, erosion and sediment yield are minimized. When the forest cover is about 30% and evenly distributed in the watershed, the erosion intensity is lower than if the forest cover is collectively distributed in the watershed. Erosion varies with different forest growth stages in the watershed; it is more serious at the young and near planting stage and is the smallest at the mature forest stage.

关键词： GeoWEPP model Eco-hydrological response watershed runoff Sediment yield Model calibration Erosion modeling

Determination of photochemically-generated reactive oxygen species in natural water

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Journal of Environmental Sciences 2009年第3期21卷 303-306页

作者： ZHAN Manjun Nanjing research institute of Environmental Protection,Nanjing 210013,china. [a]Nanjing research institute of Environmental Protection Nanjing 210013 China

Reactive oxygen species （ROS） can be produced by interactions between sunlight and light-absorbing substances in natural water environment. ROS may participate in the indirect photolysis of trace organic pollutants, therefore resulting in changes in their environmental fates and ecological risks in natural water systems. Bisphenol A （BPA）, an endocrine-disrupting chemical, exits widely in natural waters. The photodegradation of BPA promoted by ROS （-OH, 1O2, HO2./O2^-）, which were produced on the excitation of ubiquitous constituents （such as nitrate ion, humic substances and Fe（Ⅲ）-oxalate complexes） in natural water under simulated solar radiation was investigated. Both molecular probe method and electron spin resonance （ESR） test were used for the characterization of the generated ROS. It was found that .OH was photochemically produced in the presence of nitrate ions, humic substances and Fe（Ⅲ）-oxalate complexes and that 102 was produced with the presence of humic substances. The steady-state concentrations of .OH was 1.27×10^-14 mol/L in a nitrate solution, and the second-order rate constant of BPA with ＂OH was 1.01×10^10 L/（mol.s）.

关键词： reactive oxygen species Bisphenol A hydroxyl radicals singlet oxygen superoxide anion radical photodegradation

Sediment retention by check dams in the Hekouzhen-Longmen Section of the Yellow River

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International Journal of Sediment research 2008年第2期23卷 159-166页

作者： Da-Chuan RAN1,2,Quan-Hua LUO3,Zu-Hao ZHOU4,Guo-Qing WANG5,and Xiao-Hua ZHANG2 1 Senior Engineer,Xi’an University of Technology,Xi’an 710048,china 2 Senior Engineer,Yellow River institute of Hydraulic research,Zhengzhou 450003,china 3 Engineer ,Xifeng Soil and water Conservation Experimental Station,Qingyang 745000,china 4 Senior Engineer,china institute of water Resources and Hydropower research,Beijing 100038,china 5 Senior Engineer,Flood prevention office of YRCC,Zhengzhou 450003,china [a]Senior Engineer Xi'an University of Technology Xi'an 710048 china [b]Senior Engineer Yellow River institute of Hydraulic research Zhengzhou 450003 china [c]Engineer Xifeng Soil and water Conservation Experimental Station Qingyang 745000 china [d]Senior Engineer china institute of water Resources and Hydropower research Beijing 100038 china [e]Senior Engineer Flood prevention office of YRCC Zhengzhou 450003 china

Coarse sediment retention by check dams is analyzed for five typical catchments in the Hekou-Longmen section of the midstream of the Yellow River,which is an area of high coarse sediment *** catchments are the Huangfuchuan,Kuye,Wuding,Sanchuan and Qiushui River *** amount of coarse sediment retained by check dams in these areas for different periods was *** reduction due to check dams is compared with other soil conservation measures and the results show that check dams are the most effective to rapidly reduce the amount of coarse sediment entering the Yellow *** the average percentage of the drainage area with check dams for the five typical catchments reaches 3.0%,the average sediment reduction ratio can reach 60%.Therefore,to rapidly and effectively reduce the amount of sediment,especially coarse sediment,entering the Yellow River,the area percentage of check dams in the Hekou-Longmen section should be kept around 3%.The Kuye and Huangfuchuan River Basins are the preferred main catchments in which such water conservation measures are implemented.

关键词： Sediment retention Yellow River Check dam Coarse sediment Grain size

Autonomous control of multi-fingered hand

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Progress in Natural Science:Materials International 2006年第5期16卷 531-537页

作者： JIANG Li and LIU Hong (Robotics research institute, Harbin institute of Technology, Harbin 150001, china) [a]Robotics research Institue Harbin Institute of Technology Harbin China

This paper describes a novel autonomous control strategy of multi- fingered hand based on a modular control system of dexterous manipulation. A simple proportional-integral-derivative(PID) position control with friction compensation, which requires few friction parameters, is used to realize accurate and smooth trajectory tracking in pregrasp phase. In grasp and manipulation phases, an event-driven switcher is adopted to determine the switching between unconstrained position control and constrained torque control, and an improved explicit integral force control strategy is implemented to realize simultaneously stable contact transition and accurate force tracking. Experimental results have verified the effectiveness of the proposed autonomous control strategy of multi-fingered hand.

关键词： multi-fingered hand autonomous control position control impact control.

TWO-DIMENSIONAL SEDIMENT MATHEMATICAL MODEL FORUNSTEADY FLOW IN THE LOWER YELLOW RIVER

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International Journal of Sediment research 1999年第2期14卷 295-301页

作者： ZHANG Hongwu LI Dongfeng XU Yuxin ZHANG Junhua (1 Project (No. 39890200) Supported by the National Nature Science Foundation Commission and the Ministry of water conservancy 2 Yellow River institute of Hydraulic research, Zhengzhou 450003, china 3 Ye

The theoretical frame of a new two-dimensional sediment mathematical model is established on the basis of the resent research achievements about the sediment transport law of the Yellow River. The formulas of sediment carrying capacity of flow and river roughness, which reflect the features of the Yellow River, are applied to it. The finite element scheme is employed to deduce the discretized equations of the model. The pre-estimated-verified substitution is used to solve them. Verifications of the model are carried out with the flood occurring on Jinan reach of the Yellow River during the flood season in 1976. The calculation results with the model are in good agreement with the measured data.

关键词： Two-dimensional sediment mathematical model the Yellow River Model verification

EXPERIMENTAL STUDY OF MOTION OF LAMINATED LOAD

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Science in china,Ser.A 1985年第1期28卷 102-112页

作者：王兆印钱宁 institute of water conservancy and Hydroelectric Power research Beijing Qinghua University

Whnen the sediment eonoentration surpasses a certain limit, turbulence disappears and flow becomes a laminar one. The sediment moves in layers and is ealled the laminated load in this article. By using light weight plastic particle as the sedimentary material, the velocity distribution, frictional loss and dispersive foree of such a flow in pipe are studied in detail.

关键词： EXPERIMENTAL STUDY OF MOTION OF LAMINATED LOAD

Effects of the Composition of Electrodeposited Fe-Ni-P Alloy on the Thermostability and Magnetic Properties

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Journal of Materials Science & Technology 1997年第2期13卷 137-140页

作者： Chenghui GAO Baiyang ZHOU (institute for Materials research, Fuzhou University, Fuzhou 350002, china)(Manuscript received February 22, 1996, in revised form June 3, 1996) institute for Materials research Fuzhou University Fuzhou 350002 China

The magnetic properties, structure defects of electrodeposited Fe-Ni-P alloys with various compositions and the thermostability at amorphous state have been studied by DSC, positron annihilation and electronic integrating instrument methods. The results show that the thermostability of amorphous Fe-Ni-P alloys increases with Fe content. Emergence and recrystallization of stable phases defer as the P content of the coating increases. The minimum H-c, B-r and P-h occur at 9.4 P (wt pet) content. Maximum H-c, B-r and P-h occur at the weight ratio of Fe to Ni equaling to 1/9.

关键词： Ni Fe Effects of the Composition of Electrodeposited Fe-Ni-P Alloy on the Thermostability and Magnetic Properties