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Simulating the transfer and fate of hexachlorocyclohexane in recent 50 years in beijing, china

Science china Earth sciences 2005年第12期48卷 2203-2213页

作者： CAO Hongying1, LIANG Tao1 & TAO Shu2.1. Institute of Geographical sciences and Natural Resources Research, {2. Academy of sciences, beijing 100101, china 2. Laboratory for Earth Surface Processes, Peking University, beijing 100871, china 1. Institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. Laboratory for Earth Surface Processes Peking University 100871 Beijing China

Taking beijing as a study area, a dynamic fugacity model was used to simulate the transfer and fate of technical HCHs according to the physic-chemical properties of the studying environment and HCH isomers. Dynamic changes of the transfer fluxes and concentrations of HCH isomers during 1952.2.03 were simulated and the model results suggest good agreement between the calculated and measured concentrations of HCH isomers. During 1952.1983, the average input and output amount of HCHs through agricultural application and degradation are 130 t and 150 t respectively. The dominant transfer processes of HCHs in the study area are air-soil deposition, soil erosion and soil-air diffusion, transfer fluxes of these processes are 80 t?a?1, 16 t?a?1 and 11 t?a?1, which account for 92. of total transfer fluxes of HCHs isomers. There were approximately 2.3t HCHs in all environmental compartments of the study area during this period and 97% of which existed in soil compartment. Air and water advection became the dominant input sources of HCHs after 1984 when the application of technical HCHs was prohib-ited, concentration of HCHs quickly descended to a quite low level in several years. Total amount of HCHs isomers remaining in the study area environment now is less than 5% that before 1983, and this percentage may descend to 0.5% after 2. years by prediction.

关键词： fugacity model, hexachlorocyclohexane, compartment, transfer flux, fate.

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Three industries and wastewater and COD discharge of beijing

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Journal of Environmental sciences 2000年第4期12卷 474-477页

作者： WANG Yan 1, WANG Hong rui 2. NING Da tong 2.(1. beijing Municipal Research Institute of Environmental Protection, beijing 100037, china 2. Institute of Environmental sciences, beijing Normal University, beijing 100875, china) 北京市环境保护所北京 1 0 0 0 3 北京师范大学北京 1 0 0 875

With the swift development of economy, the water quality of beijing is becoming worse day by day and hampers the sustainable development obviously. In this paper, the current conditions of the municipal wastewater structure in the industrial sectors are analysed and discussed in terms of the indicators, such as direct wastewater\|discharge coefficient, complete wastewater\|discharge coefficient, direct discharge coefficient of COD and complete discharge coefficient of COD, by taking a year of 1990s as the base year. Some countermeasures are studied and the corresponding recommendations are put forward in order to improve the water environment in beijing. This provides a scientific ground for coordinating the relationship between the aquatic environment and economic growth in this city.

关键词： direct wastewater discharge coefficient (DWDC) complete wastewater discharge coefficient (CWDC) direct discharge coefficient of COD(DDC of COD) complete discharge coefficient of COD (CDC of COD)

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Floating Population Increase and Its Influence on the Urban Population Situation:A Case Study in beijing

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chinese Journal of Population,Resources and Environment 2005年第1期3卷 27-35页

作者： Wu Peilin 1,2.& Lu Qi 2.1. Shandong University of Technology, Zibo Shandong 2.5049, china 2. Institute of Geographical {2. and Natural Resources Research, chinese Academy of {2., beijing 100101, china Shandong University of Technology Zibo Shandong 255049 China Institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

Floating population is a special population group in china resulting from the implementation of household registration system. This paper uses a set of floating population survey data, population censuses data and statistical data to analyze the increase and influence of floating population on the urban population situations in beijing. It is found that beijing has experienced a rapid increase of floating population since the 1990s and that the increase of this group has become the key factor of the current population expansion in the city. Its distribution in the urban regions intensified and extended the suburbanization process of the capital. In addition, the population structures of sex, age, education and employment in beijing have changed to some extent due to the influx of floating population.

关键词： Floating population Household registration system (Hukou) Population expansion Suburbanization Population structure beijing

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Estimating possible impact of human activity on the warm season temperature in beijing since the industrial era

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chinese Science Bulletin 2010年第16期55卷 1590-1593页

作者： QIN Li1,2.& ZHOU Xin1,2.1 Institute of Geology and Geophysics,chinese Academy of {2.,beijing 10002.,china 2.Graduate University of chinese Academy of {2.,beijing 100049,china Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Graduate University of chinese Academy of sciences Beijing China

Global surface temperature shows an increasing trend over the past 100 *** and natural factors have been invoked to explain this warming, but their relative contribution and the spatial variability remain *** on a 2.50-year temperature record from a stalagmite near beijing, we explore the possible impacts of human activity on the warm season temperature in beijing since the industrial era using the method of singular spectrum analysis (SSA).The results suggest that the warm season temperature in beijing under the natural forcing should have an overall decreasing trend for the past 130 years (1870 to 2.00 AD) with an amplitude of 0.45±0.84°C, while the instrumental record and stalagmite data show an increase of 1.08°*** imply that human activity would have caused an increase in the warm season temperature of beijing for about 1.53±0.84°C compared to its natural trends, from 1870 AD to 2.00 *** results also suggest that anthropogenic forcing began to significantly influence the temperature since 1870 AD, and the effect further intensified since 1915 AD.

关键词：人类活动北京温度工业时代季节温暖估计地表气温

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Direct Optimization of Low-thrust Many-revolution Earth-orbit Transfers

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chinese Journal of Aeronautics 2009年第4期22卷 426-433页

作者： Gao Yang Academy of Opto-electronics,chinese Academy of {2.,beijing 100190,china [a]Academy of Opto-electronics Chinese Academy of Sciences Beijing 100190 China

Low-thrust Earth-orbit transfers with 10^- 5-order thrust-to-weight ratios involve a large number of orbital revolutions which poses a real challenge to trajectory optimization. This article develops a direct method to optimize minimum-time low-thrust many-revolution Earth-orbit transfers. A parameterized control law in each orbit, in the form of the true optimal control, is proposed, and the time history of the parameters governing the control law is interpolated through a finite number of nodal values. The orbital averaging method is used to significantly reduce the computational workload and the trajectory optimization is conducted based on the orbital averaging dynamics expressed by nonsingular equinoctial elements. Furthermore, Earth＇s shadowing and perturbation effects are taken into account. The optimal transfer problem is thus converted to the parameter optimization problem that can be solved by nonlinear programming. Taking advantage of the mapping between the parameterized control law and the Lyapunov control law, a technique is proposed to acquire good initial guesses for optimization variables, which results in enlarged convergence domain of the direct optimization method. Numerical examples of optimal Earth-orbit transfers are presented.

关键词： low thrust orbital transfer optimization direct method orbital averaging Lyapunov method

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A novel operation mode for spaceborne polarimetric SAR

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Science china(Information sciences) 2011年第4期54卷 884-897页

作者： QI WeiKong 1,2.& YU WeiDong 1 1 Institute of electronics,{2. Academy of sciences,beijing 100190,china 2.Graduate School of {2. Academy of sciences,beijing 100039,china 1. Institute of electronics Chinese Academy of Sciences Beijing 100190 China2. Graduate School of Chinese Academy of Sciences Beijing 100039 China

A novel operation mode for spaceborne polarimetric SAR,named polarization space-division adding polarization code-division (PSD-PCD) operation mode,is proposed in this paper through combining polarimetric SAR with elevation digital beam-forming (DBF) on *** a pulse repetition interval the up-chirp LFM sub-pulse is transmitted with horizontal polarization antenna,and with some delay the down-chip LFM subpulse is transmitted with vertical polarization antenna to realize code *** every sub-aperture receives returns from ground,SAR system uses range DBF to separate echoes relative to different sub-pulses in order to realize space *** system PRF is equal to that of single-polarization SAR,and elevation DBF help reduce range ambiguity ***,the main system parameters,including PRF,delay between two sub-pulses,radar equation and ambiguity are analyzed and compared with those of single-polarization *** results demonstrate the feasibility and validity of PSD-PCD operation mode.

关键词： spaceborne synthetic aperture radar (SAR) polarimetry digital beamforming (DBF) operation mode ambiguity ratio polarization space-division polarization code-division

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Simulation of aerodynamic performance affected by vortex generators on blunt trailing-edge airfoils

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Science china(Technological sciences) 2010年第1期53卷 1-7页

作者： YANG Ke1,2.ZHANG Lei1,3 & XU JianZhong1,2.1 Institute of Engineering Thermophysics,chinese Academy of {2.,beijing 100190,china 2.Key Laboratory of Wind Energy Utilization,chinese Academy of {2.,beijing 100190,china 3 Graduate School of chinese Academy of {2.,beijing 100190,china 1. Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China2. Key Laboratory of Wind Energy Utilization Chinese Academy of Sciences Beijing 100190 China3. Graduate School of Chinese Academy of Sciences Beijing 100190 China

An investigation was carried out by numerical simulation on a wind turbine airfoil and a blunt trailing-edge airfoil with and without vortex generators (VGs), and the performance of the airfoils was analyzed. By the simulation of airfoil DU 91-W2.2.0 it was verified that the numerical method and model were credible. Based on this airfoil, a new one with a blunt trailing edge of 6% chord was blended by symmetrically adding thickness, and its characteristics curves were obtained through computing at key angles of attack. Additionally, the pressure distribution on blended airfoil was analyzed by comparing to the airfoil without blend. The interaction of streamwise vortices induced by VGs with trailing vortex or separation vortex was considered, followed by the uncovery of how VGs can suppress the boundary layer separation.

关键词： vortex generators airfoil blunt trailing-edge

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Maximal effective baseline for polarimetric interferometric SAR forest height estimation

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Science china(Information sciences) 2012年第4期55卷 867-876页

作者： ZHOU YongSheng 1,2.3,HONG Wen 1,2.WANG YanPing 1,2.& WU YiRong 1,2.1 National Key Laboratory of Science &Technology on Microwave Imaging,beijing 100190,{2. 2.Institute of electronics,chinese Academy of sciences,beijing 100190,{2. 3 Academy of Opto-electronics,chinese Academy of sciences,beijing 100094,{2. 1. National Key Laboratory of Science & Technology on Microwave Imaging Beijing 100190 China2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China3. Academy of Opto-Electronics Chinese Academy of Sciences Beijing 100094 China

The concepts of critical baseline and maximal effective baseline have been defined for interferometric SAR (InSAR) DEM application based on the spatial decorrelation (which is a function of baseline).This paper puts forward these two concepts to polarimetric interferometric SAR (Pol-InSAR) forest height estimation *** application makes use of volume decorrelation,which is also a function of *** both the spatial decorrelation and volume decorrelation are considered to determine Pol-InSAR critical and maximal effective *** various decorrelation effects are *** the calculation formula of Pol-InSAR maximal effective baseline are presented and compared to that of *** validation,RVoG-based and PolSARpro-based simulation data and DLR ESAR data are *** concept of Pol-InSAR maximal effective baseline is of practical significance in selection of Pol-InSAR image pairs as well as in the design of further Pol-InSAR systems.

关键词： Pol-InSAR maximal baseline forest height estimation

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Experimental results and analysis of sparse microwave imaging from spaceborne radar raw data

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Science china(Information sciences) 2012年第8期55卷 1801-1815页

作者： JIANG ChengLong1,2.3,ZHANG BingChen1,2.ZHANG Zhe1,2.3,HONG Wen1,2.WU YiRong1,2.1S cience and Technology on Microwave Imaging Laboratory,beijing 100190,{2. 2. nstitute of electronics,chinese Academy of sciences,beijing 100190,{2. 3G raduate University of chinese Academy of sciences,beijing 100190,{2. 1. Science and Technology on Microwave Imaging Laboratory Beijing 100190 China2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China3. Graduate University of Chinese Academy of Sciences Beijing 100190 China

Sparse microwave imaging is a novel radar framework aiming to bring revolutions to the microwave imaging according to the theory of sparse signal *** compressive sensing(CS)is introduced to synthetic aperture radar(SAR)imaging in recent years,the current SAR sparse imaging methods have shown their advantages over the traditional matched filtering ***,the requirement for these methods to process the compressed range data results in the increase of the hardware *** the SAR sparse imaging method that directly uses the raw data is *** paper describes the method of SAR sparse imaging with raw data directly,presents the analysis of the signal-to-noise ratio(SNR)in the echo signal by combining the traditional radar equation with the compressive sensing theory,and provides the tests on 2.D simulated SAR *** simulation results demonstrate the validity of the SNR analysis,and the good performance of the proposed method while a large percentage of the raw data is *** experiment with RadarSat-1 raw data is also carried out to show the feasibility of processing the real SAR data via the method proposed in this *** method is helpful for designing new SAR systems.

关键词： sparse microwave imaging synthetic aperture radar(SAR)imaging compressive sensing signalto-noise ratio raw data

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Detection of the urban heat island in beijing using HJ-1B satellite imagery

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Science china Earth sciences 2010年第S1期53卷 67-73页

作者： YANG Jun1,GONG Peng2.ZHOU JinXing3,HUANG HuaBing2.& WANG Lei2.1 Key Laboratory of Silviculture and Conservation,Ministry of Education,beijing Forestry University,beijing 100083,{2. 2.State Key Laboratory of Remote Sensing Science,jointly sponsored by the Institute of Remote Sensing Applications,chinese Academy of sciences and beijing Normal University,beijing 100101,{2. 3 Institute of Desertification Studies,chinese Academy of Forestry,beijing 100091 {2. 1. Key Laboratory of Silviculture and Conservation Ministry of Education Beijing Forestry University Beijing 100083 China2. State Key Laboratory of Remote Sensing Science jointly sponsored by the Institute of Remote Sensing Applications Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China3. Institute of Desertification Studies Chinese Academy of Forestry Beijing 100091 China

Satellite images are used extensively in studying the urban heat island(UHI) *** evaluated the suitability of thermal infrared(TIR) data from the HJ-1B satellite for detecting UHI using a case study in *** modified algorithms for retrieving the land surface temperature(LST) from HJ-1B data were *** results were compared with LST images derived from a Landsat TM thermal band and the MODIS LST *** spatial pattern of UHI generated using HJ-1B data matched well with that produced using TM and MODIS *** the two algorithms,the mono-window algorithm performed better but further tests are *** more frequent coverage than TM and higher spatial resolution than MODIS,the HJ-1B TIR data present a unique opportunity to study thermal environments in cities in china and neighboring countries.

关键词： surface temperature NDVI mono-window algorithm single-channel algorithm

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