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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

Eco-environmental susceptibility in shangyi County,Northern Hebei Province,china

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Journal of environmental sciences 1997年第1期9卷 86-94页

作者： Liu Quanyou Chen Liding research Center for Eco-environmental sciences,chinese academy of sciences,beijing 100085,china Res. Ctr. for Eco-Environ. sciences Chinese Academy of Sciences Beijing 100085 China

In this paper,the eco-environmental susceptibility of shangyi County,Northern Hebei Province of china has been calculated by using the weighted-addition method based on expert's giv- ing a mark to each influencing factor according to their knowledge on the influence of all the factors on eco-environmental *** eco-environmental classification and distribution map were reached based on the above results,its difference is mainly result from the physical conditions and human activity,however the value of eco-environmental susceptibility is only a relative index which can not completely reflect the quality of *** work provided a basis for control- ling the further development of desertification.

关键词： eco-environmental susceptibility weighted addition method.

A comparison of hydrocarbons emission from engine running 85￣＃gasoline and M－100 methanol fuel

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Journal of environmental sciences 1994年第1期6卷 107-111页

作者： Yao Heng, Chen Zongliang(chinese research academy of environmental sciences beijing 100012, china)Yu shilin(beijing Institute of Chemical Technoiogy)

Increasing global interest in methanoi fuel has led us to investigate the exhaust emissionsof its engine. Analysis of its inorganic and organic emissions. such as CO. NO_x and hydrocarbons(total HC) have been widely reported. This paper presents an analysis of more than 20 kinds ofhydrocarbons in the emissions obtained from a spark-ignition shanghai car running 85# gasoline anda comparison with emission from a santana test car running M-100 methanol fuel. A set ofenrichment method has also been described. Test results show that at the current stage of methanolengine development the concentration of individual hydrocarbon including some poisonous substancesis lower than those of normal gasoline engine.

关键词： engine running, 85￣# gasoline M-100 methanol fuel, atmosphere, health.

Evidence of a two-component jet in the afterglow of GRB 070419A

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science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 265-266页

作者： ZHENG WeiKang1,2 & DENG Jinsong1 1 National Astronomical Observatories,chinese academy of sciences,beijing 100012,china 2 Graduate University of chinese academy of science,beijing 100049,china 1. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China 2. Graduate University of chinese academy of science Beijing 100049 China

A two-component jet model is proposed to explain the unusual afterglow of GRB *** the optical light curve,a wide "jet" with an opening angle of >30-40 degrees is assumed to produce the late shallow decay,while the three early power-law segments must be caused by a narrow jet with an opening angle of-2-4 *** energy injections to both components are *** X-ray emission may come from either the wide jet or the narrow *** the latter is correct,the jets may run into an IsM environment and the temporal index of the late energy injection may be q-0.65.

关键词： gamma-rays:bursts gamma-rays:observations

Mechanism and Defense on Malicious Code

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Wuhan University Journal of Natural sciences 2005年第1期10卷 83-88页

作者： WEN Wei-ping 1,2,3, QING si-han 1,2,31. Institute of software, the chinese academy of sciences, beijing 100080, china 2.Engineering research Center for Information security Technology, the chinese academy of sciences, beijing 100080, china 3.Graduate school of the chinese academy of sciences, beijing 100080, china Institute of software the Chinese Academy of Sciences Beijing 100080 China

With the explosive growth of network applications, the threat of the malicious code against network security becomes increasingly serious. In this paper we explore the mechanism of the malicious code by giving an attack model of the malicious code, and discuss the critical techniques of implementation and prevention against the malicious code. The remaining problems and emerging trends in this area are also addressed in the paper.

关键词： malicious code attacking model mechanism defense system security network security

Patterns of platinum-group elements in mantle peridotite, granulite xenoliths and basalt in Hannuoba

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chinese science Bulletin 1999年第18期44卷 1676-1681页

作者： CHU Xuelei, LI Xiaolin, XU Jiuhua and LIU Jianming1. The research Center of Mineral Resources Exploration , chinese academy of sciences , beijing 100101, china 2. Institute of Geology , chinese academy of sciences , beijing 100029, china 3. Institute of High Energy Physics , chinese academy of sciences , beijing 100817 , china 4. beijing University of science and Engineering , beijing 100083, china Corresponding author The research Center of Mineral Resources Exploration Chinese Academy of Sciences Beijing China Institute of Geology Chinese Academy of Sciences Beijing China Institute of High Energy Physics Chinese Academy of Sciences Beijing China beijing University of science and Engineering Beijing China

Neutron activation analysis after preconcentration of nickel sulfide fire assay was used in measurement of Ru, Ph, Pd, Os, Ir, Pt (i.e. PGE elements) and Au concentrations for basalt, mantle and granulite xenoliths in Hannuoba. The chondrite- and primitive mantle-normalized PGE patterns generally exhibit flat (for Iherzolite), negative slope (for harzburgite),

关键词： mantle xenolith granulite xenolith basalt platinum-group element Hannuoba.

A new method of ionospheric-free hybrid differential positioning based on a double-antenna CAPs receiver

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science china(Physics,Mechanics & Astronomy) 2009年第3期52卷 368-375页

作者： GUO JinYun1,2, HAN YanBen1 & CHANG XiaoTao3 1 National Astronomical Observatories, chinese academy of sciences, beijing 100012, china 2 College of Geodesy and Geomatics, shandong University of science and Technology, Qingdao 266510, china 3 chinese academy of surveying and Mapping, beijing 100039, china 1. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China 2. College of Geodesy and Geomatics Shandong University of Science and Technology Qingdao 266510 China 3. chinese academy of surveying and Mapping Beijing 100039 China

chinese Area Positioning system (CAPs) is a transmitted satellite navigation system moved by the chinese academy of sciences. Three basic modes of navigation and positioning with CAPs are given, and then a comparative analysis is made in this paper. In terms of the principle that the ionospheric delay is at an inverse ratio to the frequency square, a new ionospheric-free positioning method based on a double-antenna CAPs receiver is put forward. Then the hybrid differential observations and the solving equations and algorithms for one epoch and multi epochs are deduced according to the basic principle of the method. The method may remove the global errors in signal emission, propagation, transmission and receiving (e.g., ionospheric delay, hardware delay, and clock error). so it is very convenient for the single-epoch solution and multi-epoch navigation and positioning, and may efficiently improve the precision of real time CAPs navigation. Furthermore, the method can be used not only for the geometric orbit determination of CAPs GEO and IGsO satellites and the navigation and positioning, but also for the estimation of the tropospheric zenith delay, which is useful for the study of water vapor changes in the atmosphere. Polynomials are used in this method to express the tropospheric zenith delay and CAPs satellite orbits within the limited time interval, which reduces the num- ber of unknown parameters and thus speeds the computation.

关键词： chinese Area Positioning system (CAPs) ionospheric-free linear combination double-antenna receiver hybrid differential positioning method

sea-salt aerosol transport patterns over the Northern Hemisphere inferred from two subarctic ice core records

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science china Earth sciences 2005年第4期48卷 576-584页

作者： YAN Yuping1,2, KANG shichang2,3,5, sUN Junying4,5, Paul A. Mayewski2 & QIN Dahe5 1. National Climate Center, china Meteorological Administration, beijing 100081, china 2. Climate Change Institute, University of Maine, Orono, ME 04469, UsA 3. Institute of Tibetan Plateau research, chinese academy of sciences, beijing 100085, china 4. chinese academy of Meteorological sciences, beijing 100081, china 5. Key Laboratory of Ice Core and Cold Regions Environment, Cold and Arid environmental and Engineering research Institute, chinese academy of sciences, Lanzhou 730000, china 1. National Climate Center China Meteorological Administration 100081 Beijing China 2. Climate Change Institute University of Maine 04469 Orono ME USA 3. Institute of Tibetan Plateau research Chinese Academy of Sciences 100085 Beijing China 4. Key Laboratory of Ice Core and Cold Regions Environment Cold and Arid Environmental and Engineering Research Institute Chinese Academy of Sciences 730000 Lanzhou China 5. chinese academy of Meteorological sciences 100081 Beijing China

Atmospheric circulation reconstruction based on glaciochemical records requires knowledge of chemical concentration controls, such as source, transport pathway and strength. To gain insight into these processes, the relationships between glaciochemical records from two Northern Hemisphere sites (Mt. Logan in Yukon Territory and 20D in southern Greenland) and instrumental sea level pressure (sLP) series are investigated. Calibrations between Mt. Logan sea-salt sodium (ssNa+) concentration and sLP series show that ssNa+ concentrations are closely correlated with the autumntime (sON) Aleutian Low and the summertime (JJA) North Pacific subtropical High. Both the deepened Aleutian Low and enhanced North Pacific sub- tropical High strengthen the transport of sea-salt aerosols from the North Pacific to the Mt. Logan region. Calibrations between 20D ssNa+ concentrations and sLP series indicate that ssNa+ concentrations are closely related to the wintertime (Jan.) Icelandic Low. A deepening of the Icelandic Low strengthens winter storms and frequent cyclogenesis over the North Atlantic and pushes more sea-salt laden air masses to the Greenland ice sheet. Therefore, ice core ssNa+ records from the Mt. Logan region can be considered as a proxy for reconstructing the au- tumntime Aleutian Low and summertime North Pacific subtropical High, and the ssNa+ records from Greenland ice core (20D) may provide a proxy for reconstructing the wintertime Icelandic Low.

关键词： sea-salt aerosol, ice core records, sea level pressure, subarctic regions.

Major environmental and ecotoxicological processes of heavy metals in Lean River polluted by discharges from mining activities

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Journal of environmental sciences 1999年第3期11卷 322-327页

作者： Wang Zi\|jian sKLEAC, research Center for Eco\|environmental sciences, chinese academy of sciences, beijing\ 100085, china 中科院生态环境研究中心北京 100085

This paper summarizes the major environmental and ecotoxicological processes of heavy metals pollution from Dexing Copper Mine in Jiangxi Province based on various findings in the Cooperative Ecological research Project (CERP; Tang, 1994). It shows the knowledge necessary to elucidate metal pollution and its ecological implications. Processes devoted to the ecological implication include generation of acid mine drainage, formation of secondary minerals from precipitation, temporal and spatial distribution of metal pollutants in sediments and relevant toxicity, as well as ecosystem alternation which may relate to chemical pollution.\; From the results, it was stated that the major emphasis should be placed on the environmental processes associated with sediment pollution by heavy metals. It shows that ad/desorption on the inorganic minerals, such as Fe/Al oxyhydroxides, play an important role in the immobilization of heavy metals in this river. There were clear indications that metal pollution has resulted in the toxicological and ecological consequences and there would be the risk of secondary pollution in the way of mobilization of bound metals to the overlying water when environmental conditions are varied.

关键词： heavy metal pollution mobility toxicity ecotoxicology.