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An improved imaging algorithm for fixed-receiver bistatic SAR

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Science china(Information Sciences) 2010年第7期53卷 1461-1469页

作者： GENG XuPu1,2.3. HU YingHui1,2. YAN HongHui2.& WANG YanFei2.1graduate school of the {2. Academy of Sciences, Beijing 10003., china 2.nstitute of Electronics, {2. Academy of Sciences, Beijing 100190, china 3.eijing Institute of Environment Features, Beijing 100854, china 1. graduate school of the {2. Academy of Sciences Beijing 100039 China2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China3. Beijing Institute of Environment Features Beijing 100854 China

Based on the signal model of fixed-receiver bistatic SAR, this paper analyzes the characteristics of azimuth-variant, which includes variation of range migration curve and variation of Doppler rate caused by different azimuth position of targets. Then, an extended nonlinear chirp scaling (NLCS) algorithm is proposed, with its flowchart and phase compensation functions being provided. Simulation results show that the algorithm is available for the characteristics of azimuth-variant of fixed-receiver bistatic SAR, and good focused radar images could be acquired.

关键词： synthetic aperture radar (SAR) bistatic SAR fixed-receiver characteristics of azimuth-variant range cell migration correction (RCMC)

Thermal analysis of the baffle structure of the Solar Space Telescope

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Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1755-1764页

作者： LI Rong1,2.3.& WANG Sen1,3.1 National Astronomical Observatories,chinese Academy of Sciences,Beijing 100012.{3. 2.{2. University of chinese Academy of Sciences,Beijing 100049,{3. 3.Key Laboratory of Solar Activity,National Astronomical Observatories of chinese Academy of Sciences,Beijing 100012.{3. 1. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Key Laboratory of Solar Activity National Astronomical Observatories of Chinese Academy of Sciences Beijing 100012 China

The SST(Space Solar Telescope) is an astronomical telescope with a primary mirror of 1 m in *** observes the sun with a small view field to ensure that its high spatial resolution imaging has 0.1″-0.15″ and high SNR(signal to noise ratio).Surrounding the small view field is still the sun,which is an intense source of both heat and stray *** baffles(the main baffle,the aperture,and the outer baffle),which are used to eliminate the stray light,will change the thermal flux in the SST and will weaken the effect of the thermal control *** this study,the compatibility analysis of the thermal effect of baffle structures in SST is *** GCF(Geometry Composing Function) and BRDF(Bidirectional Reflectance Distribution Function),which are two inherent related parameters in the compatibility analysis,are *** objective and method of the compatibility analysis are *** the thermal analysis software,the temperature fields are calculated for different lengths of the main baffle,different radii of apertures,different lengths of the outer baffle with a 3. tilt angle and 16' tilt angle,and different tilt angles of the outer baffle with a 2.0 mm length.A series of configurations and sizes of the baffles are studied with the goals of both thermal control and elimination of stray *** design of the baffle structure of SST is achieved:the main baffle of length 4100 mm,the internal shield of radius 494 mm,the outer baffle of length 2.0 mm,and the outer baffle of tilt angle 3. are successfully *** paper presents the relationship between the thermal control design and stray light elimination plan in the *** aims of the optimal design of the baffle structure of SST are *** thoughts and methods of the optimal analysis are also useful for similar optical telescopes designed for solar observation.

关键词： baffle the main baffle the outer baffle GCF BRDF

Mass Spectrometric Evidence of Heparin Disaccharides for the Catalytic Characterization of A Novel Endolytic Heparinase

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Acta Biochimica et Biophysica Sinica 2004年第12期36卷 840-844页

作者： Yapeng CHAO1,3. Shaoxiang XIONG2. Xiulan CHENG1, and Shijun QIAN1* 1Institute of Microbiology, chinese Academy of Sciences, Beijing 100080, china 2.enter of Mass Spectrometry, Institute of Chemistry, chinese Academy of Sciences, Beijing 100080, china 3.6} school of the chinese Academy of Sciences, Beijing 10003., china Institute of Microbiology Chinese Academy of SciencesBeijing 100080 China graduate school of the {2. Academy of SciencesBeijing {3. China Center of Mass Spectrometry Institute of Chemistry Chinese Academy of SciencesBeijing 100080 China

Heparinase from different sources can eliminate heparin or/and heparan sulfate into various low-molecular weight heparins with different characteristics. Porcine intestinal mucosa heparin was de- graded into a series of oligosaccharides by a novel heparinase from the species Sphingobacterium. Disaccha- ride components from the digests were separated and purified by ultrafiltration and HPLC. Five major peaks appeared as three types according to their retention time. The mass spectrometry of peak I mainly gave the non-sulfated disaccharide with the mass of 3.9 Da. Peak II and III were indicated as two major monosulfated disaccharides with molecular mass of 417 and 459 Da respectively. Moreover, the peak III represented an N- acetyl disaccharide. Both peak IV and V showed the same mass of 496 Da, hinting that they were disulfate- substituted disaccharides. No trisulfate-substituted disaccharides were detected in the mixture of the heparin digest though they were abundant in the heparin structure. The results revealed that the heparinase might specifically cut the sites with low sulfated domain in heparin.

关键词： electrospray ionization-mass spectrometry heparin disaccharides heparinase high perfor- mance liquid chromatography Sphingobacterium sp.

Properties and applications of cold supersonic gas jet

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Science china(Physics,Mechanics & Astronomy) 2006年第6期49卷 709-715页

作者： ZHANG Shaofeng1,2.MA Xinwen1,2.LIU Huiping2.LI Bin1,2.& ZHU Xiaolong1,2.1. Institute of Modern Physics,chinese Academy of Sciences,Lanzhou 73.000,china 2. {2. University of chinese Academy of Sciences,Beijing 100049,china 1. Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China 2. graduate University of chinese Academy of Sciences Beijing 100049 China

By analyzing the formation mechanism of a supersonic gas jet,a set of equations which describe the atomic beam properties were established. The influence of initial temperature,initial pressure,background gas pressure and pumping speed was discussed in detail. A simulation program was developed based on the equations,and the results under different initial conditions were obtained. The results are in good agreement with the experimental data,and suggest that,in order to get much smaller transverse momentum in collision experiments,it is necessary to lower the initial temperature and the initial pressure of the supersonic gas jet,together with increasing the pumping speed. These results are very instructive for construction of a new generation of cold supersonic gas jets.

关键词： cold supersonic gas jet,zone of silence,nozzle,skimmer.

Study Progress and Trends of Strategic Environmental Assessment in china

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chinese Journal of Population,Resources and Environment 2009年第2期7卷 76-82页

作者： Cai Chunmiao1,2. 3. Shang Jincheng4 1. Northeast Institute of Geography and Agroecology, chinese Academy of Sciences, Changchun Jilin 13.012.{3. 2. Department of Geography, Harbin University, Harbin Heilongjiang 150086,{3. 3. graduate school of chinese Academy of Sciences, Beijing 10003.,{3. 4. College of Urban and Environmental Science, Northeast Normal University, Changchun Jilin 13.02.,{3. Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Changchun Jilin 130012 China Department of Geography Harbin University Harbin Heilongjiang 150086 China graduate school of {2. Academy of Sciences Beijing 100039 China College of Urban and Environmental Science Northeast Normal University Changchun Jilin 130024 China

Strategic environmental assessment (SEA) in china has developed rapidly since it was introduced into china in the 1990s. {2. government promulgated the Environmental Impact Assessment Law of china (hereinafter referred to as the EIA Law) in 2.02. In this law, it is stipulated clearly that regional and sector plans should be assessed. Through investigating materials and analyzing literatures, this article analyses the practical and academic study achievements of SEA in china that have been achieved since the EIA Law was implemented, probes into the current situation of the main level of SEA in china-plan EIA, then summarizes the development characteristics, and eventually, puts forward the development trends of SEA in china. The research conclusions can offer the foundations for comprehending systematically the progress of SEA in china.

关键词： strategic environmental assessment plan environmental impact assessment china study progress characteristics development trends

Gasdynamic characteristics of toroidal shock and detonation wave converging

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Science china(Physics,Mechanics & Astronomy) 2005年第6期48卷 739-749页

作者： TENG Honghui1,2.& JIANG Zonglin2.1. Key Laboratory of High Temperature Gas Dynamics, Institute of Mechanics, chinese Academy of Sci- ences, Beijing 100080,{3. 2. {2. University of chinese Academy of Sciences, Beijing 10003.,{3. 1. Key Laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences 100080 Beijing China 2. graduate University of chinese Academy of Sciences 100039 Beijing China

The modified CCW relation is applied to analyzing the shock, detonation wave converging and the role of chemical reactions in the process. Results indicate that the shock wave is strengthened faster than the detonation wave in the converging at the same initial Mach number. Euler equations implemented with a detailed chemical reaction model are solved to simulate toroidal shock and detonation wave converging. Gasdynamic characteristics of the converging are investigated, including wave interaction patterns, observable discrepancies and physical phenomena behind them. By comparing wave diffractions, converging processes and pressure evolutions in the focusing area, the different effects of chemical reactions on diffracting and converging processes are discussed and the analytic conclusion is demonstrated through the observation of numerical simulations.

关键词： converging, CCW relation, shock wave, detonation wave.

Improvement of different source function expressions in SWAN model for the Bohai Sea

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Progress in Natural Science:Materials International 2005年第8期15卷 720-724页

作者： YIN Baoshu1*, YANG Dezhou1, SHA Rina 1,2.and CHENG Minghua1(1. Institute of Oceanology, chinese Academy of Sciences, Qingdao 2.6071,{3. {2. of the chinese Academy of Sciences, Beijing 10003.,{3.) Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China. graduate school of the {2. Academy of Sciences Beijing 100039 China

The simulating wave nearshore （SWAN） wave model has been widely used in coastal areas, lakes and estuaries. However, we found a poor agreement between modeling results and measurements in analyzing the chosen four typical cases when we used the default parameters of the source function formulas of the SWAN to make wave simulation for the Bohai Sea. Also, it was found that at the same wind process the simulated results of two wind generation expressions （Komen, Janssen） demonstrated a large difference. Further study showed that the proportionality coefficient α in linear growth term of wave growth source function plays an unperceived role in the process of wave development. Based on experiments and analysis, we thought that the coefficient α should change rather than be a constant. Therefore, the coefficient α changing with the variation of friction velocity U*was introduced into the linear growth term of wave growth source function. Four weather processes were adopted to validate the improvement in the linear growth term. The results from the improved coefficient α agree much better with the measurements than those from the default constant coefficient α. Furthermore, the large differences of results between Komen wind generation expression and Janssen wind generation expression were eliminated. We also experimented with the four weather processes to test the new white-capping mechanisms based on the cumulative steepness method. It was found that the parameters of the new white-capping mechanisms are not suitable for the Bohai Sea, but Alkyon's white-capping mechanisms can be applicable to the Bohai Sea after amendments, demonstrating that this improvement of parameter α can improve the simulated results of the Bohai Sea.

关键词： waves SWAN model wave growth source function new proportionality coefficient formula.

Prediction of Debris-flow Danger Area by Combining Hydrological and Inundation Simulation Methods

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Journal of Mountain Science 2011年第1期8卷 1-9页

作者： CUI Peng Key Laboratory of Mountain Hazards and Earth Surface Process Chinese Academy of Sciences Chengdu 610041 China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China graduate school of {2. Academy of Sciences Beijing 100049 China

Debris flows have caused serious human casualties and economic losses in the regions strongly affected by the Ms8.0 Wenchuan earthquake of 2.o8. Debris flow mitigation and risk assessment is a key issue for reconstruction. The existing methods of inundation simulation are based on historical disasters and have no power of prediction. The rain- flood method can not yield detailed flow hydrograph and does not meet the need of inundation simulation. In this paper, the process of water flow was studied by using the Arc-SCS model combined with hydraulic method, and then the debris flow runoff process was calculated using the empirical formula combining the result from Arc-SCS. The peak discharge and runoff duration served as input of inundation simulation. Then, the dangerous area is predicted using kinematic wave method and Manning equation. Taking the debris flow in Huashiban gully in Beichuan County, Sichuan Province, china on 2. Sep. 2.o8 as example, the peak discharge of water flow and debris flow were calculated as 3..52.m3.s-1 and 2.5.66 m3.s-, with error of 4.15% compared to the measured values. The simulated area of debris-flow deposition was 161,500 m2. vs. the measured area of 144,097 m2. in error of 81.75%. The simulated maximum depth was 12.3.m, consistent with the real maximum depth between lO and 15 m according to the field survey. The minor error is mainly due to the flow impact on buildings and variations in cross-section configuration. The present methodology can be applied to predict debrisflow magnitude and evaluate its risk in other watersheds inthe earthquake area.

关键词： Debris flow Arc-SCS model Inundation simulation Risk analysis Wenchuan earthquake

Comparison of the influence factors on NDVI for CCD camera and WFI imager on CBERS-02

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Science china(Technological Sciences) 2005年第S2期48卷 100-115页

作者： YU Tao1,3. LI Xiaoying1,2.3. ZHANG Yong1,2.3. ZHAO Feng1,2.3. GU Xingfa1,3.4, ZHU Li1,2.3. WANG Pengxin5 & MIN Xiangjun6 1. State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Application, CAS, Bei- jing 100101, china 2. graduate University of {2. Academy of Sciences, Beijing 10003., china 3. The Center for National Spaceborne Demonstration, Beijing 100101, china 4. Institut National de la Recherche Agronomique, Climat Sol Environnement, 84914 Avignon, France 5. College of Information and Electrical Engineering, china Agricultural University, Beijing 100083. china 6. china Center for Resource Satellite Data and Application, Beijing 10083., china 1. State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Application CAS 100101 Beijing China 2. The Center for National Spaceborne Demonstration 100101 Beijing China 3. graduate University of chinese Academy of Sciences 100039 Beijing China 4. Institut National de la Recherche Agronomique Climat Sol Environnent 84914 Avignon France 5. College of Information and Electrical Engineering China Agricultural University 100083 Beijing China 6. china Center for Resource Satellite Data and Application 100830 Beijing China

CCD and WFI are payloads in the visible light and near infrared bands on CBERS satellites and they have not been applied widely, especially WFI. This article mainly probes into the potential of these two sensors’ application in the vegetation monitoring and analyses the influences of radiometric calibration, atmosphere conditions and sun-observing geometry, etc. on NDVI obtained from these two sensors respectively. In addition it analyses the effect of the spectral response difference of red and near infrared spectral bands in CCD and WFI sensors on NDVI. Results indicate that radiometric calibration is the most important factor on NDVI, which cannot be applied to vegetation monitoring without radiometric calibration. Results also demonstrate that near surface NDVI is different greatly from that of TOA which change with atmosphere conditions. The study shows that NDVI is also affected by the non-lambertian character of surface and the change of the atmospheric path with the observing geometry. And NDVI of WFI is higher than that of CCD. They are very different because of their spectral difference, but they have a good linear relevant relationship.

关键词： CCD WFI NDVI LAI.