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349篇 您的检索式:作者名="Li, BY"
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1A very strong summer monsoon event during 30-40 kaBP in the Qinghai-Xizang (Tibet) Plateau and its relation to precessional cycle显示文摘Guliya ice core records, high lake-level records in the Qinghai-Xizang Plateau and at its north side as well as vegetation succession records indicated that during the period of 30-40 kaBP, namely the later age of the megainterstadial of last glacial period, or the marine oxygen isotope stage 3, the climate of the Qinghai-Xizang Plateau was exceptionally warm and humid, the temperature was 2-4℃ higher than today and the precipitation was 40% to over 100%Shi, YF Liu, XD Li, BY Yao, TD 1999Chinese Science Bulletin1999,44,20:40
2Relationships between δ ^(18)O in summer precipitation and temperature and moisture trajectories at Muztagata, western China显示文摘Based on summer observations of stable isotope of precipitation at Muztagata, western China, during 2002―2003, this paper presents the relationship between δ 18O in precipitation and air temperature, and discusses the effect of moisture transport on δ 18O in precipitation. Results show that air temperature correlates positively with δ 18O in precipitation, and the temperature effect controls the δ 18O of precipitation in this area. The Muztagata region exhibits high δ 18O values in summer precipi-tation, similar to those shown at stations in adjacent regions. According to the results of our model set up to trace the moisture trajectories, the westerlies and local moisture circulation contribute to varia-tions of oxygen isotopes in precipitation. In addition, the impacts of the moisture transport distance, the moisture transport level, and the incursion of the polar air mass also influence the variations of δ 18O in precipitation. The moisture origins and transport mechanisms also contribute to the variation of δ 18O in precipitation at Muztagata.YU Wusheng1,2, YAO Tandong1,2, TIAN Lide1,2, LI Zhen2, SUN Weizhen2 & WANG Yu2 1. Laboratory of Environment and Process on Tibetan Plateau, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China 2. Key Laboratory of Cryosphere and Environment, Jointly Established by Cold and Arid Regions Environmental and Engi-neering Research Institute and Institute of Tibetan Plateau Research, Chinese Academy of Sciences and Chinese Academy of Meteorological Sciences, China Meteorological Administration, CAS, Lanzhou 730000, China 2006Science China Earth Sciences2006,49,1:18
3Radiometric cross-calibration of the CBERS-02 CCD camera with the TERRA MODIS显示文摘For the application of the CCD camera, the most important payload on CBERS-02, the key is to provide long-term stable radiometric calibration coefficients. Although the vicarious calibration had been proved successful, it had its limitations such as test site requirement and unsuitable for historical data. Cross-calibration is one of the alternative methods, but it needs synchro surface spectrum to achieve spectral band matching factors. Our effort is to probe the influences on these factors. Simulations with a lot of surface spectrum showed that the factors changed with the viewing geometry, atmospheric condition and surface targets. However, simulating with the same viewing geometry and atmospheric condition, the spectral band matching factors of the same or similar surface targets’ spectrum acquired from different dates and different places would like to be consistent to each other within 1%―5%. Thus, the synchro measurement data can be substituted by the same or similar target from other source. Based on this method, using the MODIS as the reference, the cross-calibration was performed for CCD camera. The research demonstrated that the traditional method with single calibration site was inappropriate for CCD camera, since the offsets for its four spectral bands were not zeros. With four calibration sites, these offsets were obtained. And the camera was detected to degrade with dates based on four times of cross-calibrations.LI Xiaoying1,2,3, GU Xingfa1,3,4, MIN Xiangjun5, YU Tao1,3, FU Qiaoyan5, ZHANG Yong1,2,3 & LI Xiaowen1,3 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 100039, 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. China Center for Resource Satellite Data and Application, Beijing 100830, China 2005Science China(Technological Sciences)2005,48,S2:15
4Variations of δ^(18)O in precipitation from the Muztagata Glacier, East Pamirs显示文摘Expeditions to Muztagata (in the eastern Pamirs) during the summer seasons of 2002 and 2003 collected precipitation samples and measured their oxygen isotopes. The δ 18O in precipita-tion displays a wide range, varying from ?17.40‰ to +1.33‰ in June-September 2002 and from ?22.31‰ to +4.59‰ in May-August 2003. The δ 18O in precipitation correlates with the initial tem-perature of precipitation during the observing periods. The positive correlation between δ 18O and tem- perature suggests that δ 18O can be used as an indicator of temperature in this region. The δ 18O values in fresh-snow samples collected from two snow events at different elevations on the Muztagata Gla-cier show a strong “altitude effect”, with a ratio of nearly ?0.40‰ per 100 m from 5500 m to 7450 m.LI Zhen1, YAO Tandong1,2, TIAN Lide1,2, XU Baiqing1,2 & Wu Guangjian2 1. Key Laboratory of Cryosphere and Environment, Jointly Established by Cold and Arid Regions Environmental and Engi-neering Research Institute and Institute of Tibetan Plateau Research, Chinese Academy of Sciences and Chinese Academy of Meteorological Sciences, China Meteorological Administration, CAS, Lanzhou 730000, China 2. Laboratory of Environment and Process on Tibetan Plateau, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China 2006Science China Earth Sciences2006,49,1:14
5HJ-1A HSI on-orbit radiometric calibration and validation research显示文摘The calibration experiment data at Dunhuang radiometric calibration site in October, 2008 were used to achieve the on-orbit radiometric calibration for HJ-1A hyper spectral imager (HSI). Two other field experiments data were used to validate the Dunhuang calibration results. One field experiment took place in Inner-Mongolia, China in September, 2008, and the other field experiment took place in Lake Frome, Australia in February, 2009. Finally, the ‘confidence interval of calibration error’ concept was put forward for quantitatively computing the calibration coefficient error confidence interval. The results showed that the Dunhuang calibration results in 2008 had high reliability. The confidence intervals of calibration error for all HSI channels were between 2% to 12%, which could satisfy the requirement of the HSI quantitative applications.GAO HaiLiang1,2,3*, GU XingFa1,3*, YU Tao1,3, GONG Hui1,2,3, LI JiaGuo1,2,3 & LI XiaoYing1,3 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 100039, China 3 Center for National Spaceborne Demonstration, Beijing 100101, China 2010Science China(Technological Sciences)2010,53,11:10
6Synchronous estimation of DTM and fractional vegetation cover in forested area from airborne LIDAR height and intensity data显示文摘We proposed a method to separate ground points and vegetation points from discrete return,small footprint airborne laser scanner data,called skewness change algorithm.The method,which makes use of intensity of laser scanner data,is especially applicable in steep,and forested areas.It does not take slope of forested area into account,while other algorithms consider the change of slope in steep forested area.The ground points and vegetation points can be used to estimate digital terrain model(DTM) and fractional vegetation cover,respectively.A few vegetation points which were classified into the ground points were removed as noise before the generation of DTM.This method was tested in a test area of 10000 square meters.A LiteMapper -5600 laser system was used and a flight was carried out over a ground of 700―800 m.In this tested area,a total number of 1546 field measurement ground points were measured with a total station TOPCON GTS-602 and TOPCON GTS -7002 for validation of DTM and the mean error value is -18.5 cm and the RMSE(root mean square error) is ±20.9 cm.A data trap sizes of 4m in diameter from airborne laser scanner data was selected to compute vegetation fraction cover.Validation of fractional vegetation cover was carried out using 15 hemispherical photographs,which are georeferenced to centimeter accuracy by differential GPS.The gap fraction was computed over a range of zenith angles 10° using the gap light analyzer(GLA) from each hemispherical photograph.The R2 for the regression of fractional vegetation cover from these ALS data and the respective field measurements is 0.7554.So this study presents a method for synchronous estimation of DTM and fractional vegetation cover in forested area from airborne LIDAR height and intensity data.BAO YunFei1,2,CAO ChunXiang1,ZHANG Hao1,CHEN ErXue3,HE QiSheng1,2,HUANG HuaBing1,LI ZengYuan3,LI XiaoWen1,4 & GONG Peng1 1 State Key Laboratory of Remote Sensing Science,jointly sponsored by the Institute for Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University,Beijing 100101,China 2 Graduate University of the Chinese Academy of Sciences,Beijing 100049,China 3 Institute of Forest Resource Information Technique,the Chinese Academy of Forestry,Beijing 100091,China 4 Research Center for Remote Sensing and GIS,Department of Geography and Beijing Key Laboratory for Remote Sensing of Environment and Digital Sites,Beijing Normal University,Beijing 100875,China 2008Science China(Technological Sciences)2008,51,S2:10
7Quantitative estimation of the shrub canopy LAI from atmosphere-corrected HJ-1 CCD data in Mu Us Sandland显示文摘The leaf area index(LAI) is an important ecological parameter that characterizes the interface between vegetation canopy and the atmosphere.In addition,it is used by most process-oriented ecosystem models.This 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 Sandland.MODTRAN(Moderate Resolution Atmospheric Radiance and Transmittance Model) was used for atmospheric correction.Shrubland 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 other.The fraction of sunlit background is related to the shrub LAI.With the support of HJ-1 CCD data,we employ linear spectral unmixing to obtain the fraction of sunlit background in an atmospherically corrected HJ image.In addition,we use the measured shrub canopy structural parameters for shrub communities to invert the geometric-optical model and retrieve the pixel-based shrub LAI.In total,18 sample plots collected in Wushen Banner of Inner Mongolia are used for validation.The results of the shrub LAI show good agreement with R2 of 0.817 and a root-mean-squared error of 0.173.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,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 2010Science China Earth Sciences2010,53,S1:6
8Absolute radiometric calibration of CBERS-02 IRMSS thermal band显示文摘Based on the laboratory calibration before launch of CBERS-02 IRMSS thermal infrared channel, the onboard blackbody calibration, the radiometric cross- calibration against TERRA MODIS corresponding channel and the in-flight field calibration at Lake Qinghai: water surface radiometric calibration test site of China on Aug. 17, 2004 are carried out in this research. When making onboard blackbody calibration of CBERS-02 IRMSS, it is necessary to understand inside structures and light path in IRMSS camera and receive and process calibration blackbody signals at normal and high temperatures. Onboard blackbody calibration results of each detector are very important to relative radiometric calibration of images processing and absolute radiometric calibration of each detector. In-flight field calibration mainly contains field experiments, obtaining synchronous images, spectrum marching and MODTRAN radiative transmi- ssion computation. Radiometric cross-calibration of CBERS-02 IRMSS thermal band against TERRA MODIS selected 6 times synchronous images of two sensors passing through Lake Qinghai and Lake Taihu from August to December, 2004 to compute the cross calibration data. Combining the in-flight field calibration and radiometric cross calibration data, the absolute radiometric calibration coefficients are calculated by the linear regression method. This new calibration model can obviously control the radiometric calibration uncertainties aroused by the single point method used in the in-flight calibration of CBERS-02 IRMSS, this kind of sensors cannot receive the cosmic background radiation. In this research, the radiometric calibration coefficients obtained through the linear regression model are 8.53 (gain, unit: DN/W m?2sr?1μm?1) and 44.92 (offset, unit: DN).ZHANG Yong1,2,3, GU Xingfa1,3,4, YU Tao1,3, ZHANG Yuxiang5, CHEN Liangfu1,3, LI Xiaoying1,2,3, LI Xiaowen1,3 & HE Liming6 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 100039, 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. National Satellite Meteorological Center, Beijing 100081, China 6. State Environmental Protection Administration, Beijing 100029, China 2005Science China(Technological Sciences)2005,48,S2:6
9Spatial prediction and analysis of Himalayan marmot plague natural epidemic foci in China based on HJ-1 satellite data显示文摘Plague,caused by the gram-negative bacterium Yersinia pestis,is a serious and rapidly progressing illness in humans that can be fatal if not treated effectively.The Qinghai-Tibet Plateau is the largest area of natural Himalayan marmot(Marmota himalayana) plague foci in China and covers more than 630000 km2.Akesai County in Gansu Province is a part of this natural focus of plague and was chosen as a study area.Our study used an ecological niche modeling(ENM) approach to predict the potential distribution of the Himalayan marmot.Environment and Disaster Monitor Satellite(HJ-1) data was used to investigate environment factors that affect plague host animal activity.Host animal point data from active surveillance was combined with environmental variables from the HJ-1 satellite and other databases,and the models of the potential distribution of Himalayan marmot were produced with the Genetic Algorithm for Rule-Set Production(GARP).The probability of marmot presence was divided into 0-5%,5%-20%,20%-40%,40%-80%,and 80%-100% subgroups.Areas with 80%-100% probability exhibited the greatest potential for the presence of Himalayan marmot.According to the predicted potential distribution of Himalayan marmot in the study area,active surveillance of plague hosts and plague control and prevention could be more efficient.GAO MengXu1,4,LI XiaoWen1,2,CAO ChunXiang1,ZHANG Hao1,LI Qun3,ZHOU Hang3 HE QiSheng1,4,XU Min1,4,ZHAO Jian1,4,ZHENG Sheng1,4 & CHEN Wei1,4 1State 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 2School of Geography,Beijing Normal University,Beijing 100875,China 3Office for Disease Control and Emergency Response,Chinese Center for Disease Control and Prevention,Beijing 102206,China 4Graduate University of Chinese Academy of Sciences,Beijing 100049,China 2010Science China Earth Sciences2010,53,S1:5
10Remote sensing based shrub above-ground biomass and carbon storage mapping in Mu Us desert,China显示文摘The estimation of above-ground biomass(AGB) and carbon storage is very important for arid and semi-arid ecosystems.HJ-1A/B satellite data combined with field measurement data was used for the estimation of shrub AGB and carbon storage in the Mu Us desert,China.The correlations of shrub AGB and spectral reflectance of four bands as well as their combined vegetation indexes were respectively analyzed and stepwise regression analysis was employed to establish AGB prediction equation.The prediction equation based on ratio vegetation index(RVI)was proved to be more suitable for shrub AGB estimation in the Mu Us desert than others.Shrub AGB and carbon storage were mapped using the RVI based prediction model in final.The statistics showed the western Mu Us desert has relatively high AGB and carbon storage,and that the gross shrub carton storage in Mu Us desert reaches 16 799 200 t,which has greatly contributed to the carbon fixation in northern China.XU Min 1,2,CAO ChunXiang 1,TONG QingXi 1,LI ZengYuan 3,ZHANG Hao 1,HE QiSheng 1,2,GAO MengXu 1,2,ZHAO Jian 1,2,ZHENG Sheng 1,2,CHEN Wei 1,2 & ZHENG LanFen 1 1State 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 School of the Chinese Academy of Sciences,Beijing 100049,China 3 Research Institute of Forest Resources and Information Techniques,Chinese Academy of Forestry,Beijing 10009,China 2010Science China(Technological Sciences)2010,53,S1:5
11TWO-DIMENSIONAL SEDIMENT MATHEMATICAL MODEL FORUNSTEADY FLOW IN THE LOWER YELLOW RIVER显示文摘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.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 1999International Journal of Sediment Research1999,14,2:5
12In flight MTF monitoring and compensation for CCD camera on CBERS-02显示文摘In this article, the approach of simulating ideal tarp scene was proposed to determine the MTF for CCD camera on CBERS-02. The MTF acquired from this technique was compared to those from some common methods. MTFs achieved from different approaches were employed to compensate the CCD images based on three restoration algorithms: the iterative method, the Wiener filter and the modified inverse filter (MIF). The two-dimensional MTF was established with the value at frequency 0.5 for 45° directional MTF as the value at its four corners. This article addressed the variations of the restored CCD images with different techniques of constructing two-dimensional MTF, restoring algorithms and determining the in-flight MTFs. Results showed images restored with the MTF determined from the technique of simulating ideal tarp scene represent the real scene best. And the restoration technique based on the MIF would produce better restored images than the other two techniques. This research also demonstrated that the two-dimensional MTF used for restoration should be interpolated under the control of the MTF for 45° axis, rather than by multiplying the cross-orbit MTF with along-orbit MTF.GU Xingfa1,2,3, LI Xiaoying1,2,4, MIN Xiangjun5, YU Tao1,2, SUN Jijuan5, ZENG Yong1,2,4, XU Hua1,2 & GUO Ding2,6 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. The Center for National Spaceborne Demonstration, Beijing 100101, China 3. Institut National de la Recherche Agronomique, Climat Sol Environnement, 84914 Avignon, France 4. Graduate University of Chinese Academy of Sciences, Beijing 100039, China 5. China Center for Resource Satellite Data and Application, Beijing 100830, China 6. University of Electronic Science and Technology of China, Chengdu 610054, China 2005Science China(Technological Sciences)2005,48,S2:4
13Loose architecture of multi-level massive geospatial data based on virtual quadtree显示文摘This paper proposed a virtual quadtree (VQT) based loose architecture of multi-level massive geospatial data for integrating massive geospatial data dispersed in the departments of different hierarchies in the same sector into a unified GIS (Geographic Information System) platform. By virtualizing the nodes of the quad-tree,the VQT separates the structure of data organization from data storage,and screens the difference between the data storage in local computer and in the re-mote computers in network environment. And by mounting,VQT easily integrates the data from the remote computers into the local VQT so as to implement seam-less integration of distributed multi-level massive geospatial data. Based on that mode,the paper built an application system with geospatial data over 1200 GB distributed in 12 servers deployed in 12 cities. The experiment showed that all data can be seamlessly rapidly traveled and performed zooming in and zooming out smoothly.YANG ChongJun,WU Sheng,REN YingChao,FU Li,ZHANG FuQing,WANG Gang,TAN Jian,LIU DongLin,MA ChaoJi & LIANG Li 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 2008Science China(Technological Sciences)2008,51,S1:4
14Development of environmental monitoring satellite systems in China显示文摘With the increase in global environmental problems,the necessity and urgency of remote sensing technology being applied to environmental monitoring has been widely recognized around the world.China has launched the environment and disaster monitoring and forecasting small satellite constellation HJ-1A/B and the FY3 atmosphere and environmental satellite,but they still cannot fully satisfy requirements for environmental monitoring.This paper summarizes the current status of satellite environmental monitoring in China and the existing problems of inadequate load design and low data utilization efficiency,and discusses the demand for environmental monitoring satellites.Based on the development of foreign satellite systems for environmental monitoring,the future development and key tasks of the environmental monitoring satellite system in China is discussed,as are some related initiatives.LI GuoPing1 & CAO ChunXiang2 1 School of Earth and Space Sciences,Peking University,Beijing 100871,China 2 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 2010Science China Earth Sciences2010,53,S1:3
15Interactions of pyrogallol red with proteins and the determination of proteins by resonance light-scatteringHu Xiaoli, female, 35 years old, instructor. * Supported by the National Natural Science Foundation of China (NSFC) and the Municipal Science Foundation of Chongqing for Young and Middle Scientists (No: 97-4729). Hu Xiaoli, Feng Ping, Li Yua 1998西南师范大学学报(自然科学版)1998,23,5:3
16A LEGENDRE PSEUDOSPECTRAL METHOD FOR SOLVINGNONLINEAR KLEIN-GORDON EQUATION显示文摘A Legendre pseudospectral scheme is proposed for solving initial-boundary value problem of nonlinear Klein-Gordon equation. The numerical solution keeps the discrete conservation. Its stability and convergence are investigated. Numerical results are also presented, which show the high accuracy. The technique in the theoretical analysis provides a framework for Legendre pseudospectral approximation of nonlinear multi-dimensional problems.Li, X Guo, BY 1997Journal of Computational Mathematics1997,15,2:3
17Grain size record of microparticles in the Muztagata ice core显示文摘The dust transport and sediment characteristics are discussed based on analysis of mi-croparticle size and size distribution in the Muztagata ice core at 6350 m a.s.l. The finer particles with diameter of 1―5 μm are the dominant fraction in number, while middle and coarse particles mainly contribute to the total volume. The lognormal distribution characteristics can be seen for some high concentration samples, showing that model size and standard variation are greater than that in the Greenland ice cores. However, size-volume distribution of some low concentration samples is ab-normal. Those distributions reflect the dust deposit process in high mountain glaciers at mid-low lati-tudes and show differences from those in polar ice sheet.WU Guangjian1,2, YAO Tandong1,2, XU Baiqin1,2, LI Zheng2, TIAN Lide1,2, DUAN Keqin2 & WEN Linke2 1. Laboratory of Environment and Process on Tibetan Plateau, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China 2. Key Laboratory of Cryosphere and Environment, Jointly Established by Cold and Arid Regions Environmental and Engi-neering Research Institute and Institute of Tibetan Plateau Research, Chinese Academy of Sciences and Chinese Academy of Meteorological Sciences, China Meteorological Administration, Lanzhou 730000, China 2006Science China Earth Sciences2006,49,1:3
18RHEOLOGICAL PROPERTIES OF METAL INVECTION MOLDING BINDER AND FEEDSTOCK显示文摘RHEOLOGICALPROPERTIESOFMETALINVECTIONMOLDINGBINDERANDFEEDSTOCK①LiYimin,QuXuanhui,HuangBaiyun,QiuGuanghanNationalKeyLaboratory...Li, YM Qu, XH Huang, BY Qiu, GH 1997中国有色金属学会会刊:英文版1997,7,3:2
19Analysis of forest backscattering characteristics based on polarization coherence tomography显示文摘It is difficult to make an inventory of vertical profiles of forest structure parameters in field measurements.However,analysis and understanding of forest backscattering characteristics contribute to estimation and detection of forest vertical structure because of the close relationships between backscattering characteristics and structure parameters.The vertical structure function in the complex interferometric coherence definition,which represents the vertical variation of microwave scattering with the penetration depth at a point in the 2-D radar image and can be used to analyze the forest backscattering characteristics,can be reconstructed from polarization coherence tomography(PCT).Based on PCT,the paper analyzes the forest backscattering characteristics and explores the inherent relationship between the result of PCT and the forest structure parameters from numerical simulation of Random Volume over Ground model(RVoG),Polarimetric SAR interferometry(PolInSAR)simulation of forest scene and PolInSAR data at L-band of the test site Traunstein.Firstly,the effects of the extinction coefficient and surface-to-volume scattering ratio in RVoG model on vertical backscattering characteristics are analyzed by means of numerical simulation.Secondly,by applying PCT to L-band POLInSAR simulations of forest scene,different variations of vertical backscattering due to different extinction coefficients and the ratios of surface-to-volume scattering resulting from different polarizations,forest types and densities are displayed and analyzed.Then a concept of relative average backscattering intensity is presented,and the factors which affect its vertical distribution are also discussed.Preliminary results show that there is high sensitivity of the vertical distribution of forest relative average backscattering intensity to the polarization,forest type and density.Finally,based on repeat pass DLR E-SAR L-band airborne POLInSAR data,the capability of PCT technology for detection of forest layer,type and density is discussed.LUO HuanMin 1,LI XiaoWen 1,2,CHEN ErXue 3,CHENG Jian 4 & CAO ChunXiang 21 Institute of Geo-Spatial Information Science and Technology,University of Electronic Science and Technology of China,Chengdu 610054,China 2 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 3Institute of Forest Resources Information Technique of Chinese Academy of Forestry,Beijing 100091,China 4 School of Electronic Engineering,University of Electronic Science and Technology of China,Chengdu 610054,China 2010Science China(Technological Sciences)2010,53,S1:2
20Influence of Nitrogen Flow Rate on the Microstructure and Properties of N and Me (Me=Cr,Zr) Co-doped Diamond-like Carbon Films显示文摘In this paper,Me (Me=Cr,Zr) and N co-doped diamond like carbon (DLC-MeN) composite films were prepared on cemented carbide substrates by pulsed bias arc ion plating.The effect of nitrogen flow rates on the microstructure and properties of the films were investigated by X-ray photoelectron spectroscopy (XPS),Raman spectra,grazing incident X-ray diffraction (GIXRD),high resolution transmission electron microscopy (HRTEM) and nano-indentation.Raman,GIXRD and HRTEM results show that the deposited films are nanocomposite films with MeN nanocrystalline phase embedded within DLC amorphous matrix,which are vital for the mechanical properties of the films.The nitrogen flow rate has significant effect on the compositions and structures and hence on the hardness and elastic modulus of the films,and increasing nitrogen flow rate decreases drastically the hardness and elastic modulus of the films.Zhiyun Han,Hongkai Li,Guoqiang Lin and Chuang Dong Key Laboratory for Material Modification by Laser,Ion and Electron Beams,Dalian University of Technology,Dalian 116085,China 2010Journal of Materials Science & Technology2010,26,11:2
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