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Thresholds of geographic environmental elements in sediment yield of drainage basins

Science china Earth sciences 2005年第2期48卷 230-240页

作者： CHEN Hao, ZHOU Jinxing, CAI Qiangguo, LU Zhongchen & LI Zhongyan institute of Geographic sciences and Natural Resources research,{3., Beijing 100101, china institute of Forestry Science, chinese academy of Forestry Science, Beijing 100091, china research Center for Eco-Environment sciences,{3., Beijing 100085, china Computing institute of Science and engineering, North china Electric Power University, Beijing 102206, china 1. institute of Geographic sciences and Natural Resources research Chinese Academy of Sciences 100101 Beijing China 2. institute of Forestry Science Chinese Academy of Forestry Science 100091 Beijing China 3. research Center for Eco-Environment sciences Chinese Academy of Sciences 100085 Beijing China 4. Computing institute of Science and engineering North China Electric Power University 102206 Beijing China

Threshold of environmental elements in drainage basin sediment yield refers to, under effect of climate, underlying surface and human activity, a turning point of abrupt changes in drainage sediment yield related to environmental element characteristics. Previous studies on threshold of sediment yield of relevant drainage basins were mainly concentrated on impact of natural zones with a few researches on impact of other environmental elements. Particularly studies on compound environmental element threshold in drainage basin sediment yield remain blank today. Studies indicate that sediment yield in drainage basins is affected by compound interactions and complex actions. Based on single element analysis, the present paper gives quantitatively compound threshold of environmental elements affecting sediment yield of the drainage basin between Hekouzhen and Tongguan in the middle Yellow River by the method of multi-variant, polynomial formula regression analysis.

关键词： middle Yellow River, environmental element, sediment, sediment delivery mudule, threshold.

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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. {3. of Geology , chinese academy of sciences , Beijing 100029, china 3. {3. 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.

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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.{3. 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

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Magnetic characteristics of dustfall in urban area of north china and its environmental significance

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Science china Earth sciences 2007年第11期50卷 1724-1732页

作者： XIA DunSheng1,2, YANG LiPing2, MA JianYing1, YU Ye1, WANG Guan2 & CHEN FaHu2 1 Key Laboratory of Desert and Desertification, institute of cold and arid {3. Environmental and engineering, chinese academy of sciences, lanzhou 73.000, china 2 CAEP, Key Laboratory of West china’s Environmental System (Ministry of Education), lanzhou University, lanzhou 73.000, china 1. Key Laboratory of Desert and Desertification Institute of Cold and Arid Regions Environmental and Engineering Chinese Academy of Sciences Lanzhou 730000 China 2. CAEP Key Laboratory of West China’s Environmental System (Ministry of Education) Lanzhou University Lanzhou 730000 China

Urban particulate pollutants not only affect urban air quality but also directly threaten public health. lanzhou has been one of the most seriously polluted cities in the world due to its special geophysical location and weather conditions, which makes it an ideal place for urban particulate pollution study. In this study a set of environmental magnetic parameters (χ_(1f),χ_(fd)%, χ_(ARM), SIRM, HIRM, SOFT and back field IRM) were measured and analyzed for the dustfall samples collected monthly during 1997.4—2000.5 and 2004.11—2005.10 at lanzhou University campus (KLD and CCS) and at a clear site of Gaolanxian (GLX). Results demonstrate that the main magnetic minerals in the dustfall are magnetite, with some maghaemite and haematite. Cross plots of M_(rs)/M_s vs. B_(cr)/B_c and χ_(fd)% vs. χ_(ARM)/SIRM indicate that the main magnetic grain sizes are pseudo-single-domain (PSD). The high concentration of magnetic minerals in the dustfall indicates that lanzhou is seriously polluted. The main pollution sources are anthropogenic activities and nature dust, with the former posing a great threat during the whole year, which is different from the general view that the natural dust is the main contributor in summer. With great efforts of the government and local authority in the past decades, the air quality in lanzhou has been improved in winter, but it is not so obvious in summer. This study also reveals that as a simple, rapid and accurate technology, environmental magnetism could be a valuable tool for urban pollution study.

关键词： environmental magnetism,dustfall,air pollution,lanzhou

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A new interpolation method for Antarctic surface temperature

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Progress in Natural Science:Materials International 2009年第12期19卷 1843-1849页

作者： Yetang Wang~(a,b),Shugui Hou~(b,c,*) a Monitoring Centre of Ocean Environment of Shandong Province,Yantai 264006,china b State Key Laboratory of Cryospheric Science,cold and arid {3. Environmental and engineering research institute, chinese academy of sciences,lanzhou 73.00,china c MOE,Key Laboratory for Coast and Island Development,School of Geographic and Oceanographic sciences,Nanjing University,Nanjing 210093.china [a]Monitoring Centre of Ocean Environment of Shandong Province Yantai 264006 China [b]State Key Laboratory of Cryospheric Science Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 73000 China [c]MOE Key Laboratory for Coast and Island Development School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210093 China

We propose a new methodology for the spatial interpolation of annual mean temperature into a regular grid with a geographic resolution of 0.01°for Antarctica by applying a recent compilation of the Antarctic temperature data.A multiple linear regression model of the dependence of temperature on some geographic parameters(i.e.,latitude,longitude,and elevation) is proposed empirically,and the kriging method is used to determine the spatial distribution of regional and local deviations from the temperature calculated from the multiple linear regression *** modeled value and residual grids are combined to derive a high-resolution map of surface air temperature. The performance of our new methodology is superior to a variety of benchmark methods(e.g.,inverse distance weighting,kriging, and spline methods) via cross-validation *** simulation resembles well with those distinct spatial features of surface temperature,such as the decrease in annual mean surface temperature with increasing latitude and the distance away from the coast line; and it also reveals the complex topographic effects on the spatial distribution of surface temperature.

关键词： Surface temperature DEM Antarctica

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Palaeoenvironmental implication of the Plio-Pleistocene loess deposits in southern Tarim Basin

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chinese Science Bulletin 2002年第8期47卷 700-704页

作者： ZHENG Hongbo, CHEN Huizhong & CAO JunjiLaboratory of Marine Geology, Tongji University, Shanghai 200092, china institute of Earth Environment, chinese academy of sciences, Xi’an 710054, china institute of Environment and engineering of cold and arid Regio Laboratory of Marine Geology Tongji University Shanghai 200092 China

The sedimentary characteristics, grain-size distribution, geochemical composition and surface characteristics of quartz grains, together with palaeoenvironmental reconnaissance, all point to an aeolian origin for the intercalated siltstone beds in the Plio-Pleistocene Artux and Xiyu Formations along the southern margins of the Tarim Basin, indicating that loess deposition in the region started, at least, in the Early Pliocene. Loess deposition in the southern Tarim Basin was a response to the global deterioration, which might be attributed to the uplift of the Tibetan Plateau.

关键词： eolian loess Plio-Pleistocene Tarim Basin.

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Identification and Evolution of Groundwater Chemistry in the Ejin Sub-Basin of the Heihe River, Northwest china

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Pedosphere 2007年第3期17卷 331-342页

作者： SU Yong-Hong FENG Qi ZHU Gao-Feng SI Jian-Hua ZHANG Yan-Wu cold and arid regions Environmental and {3. research institute Chinese Academy of Sciences Lanzhou730000 （China） School of Mathematics and Statistics Lanzhou University Lanzhou 730000 （China）

Hydro-chemical characteristics of groundwater and their changes as affected by human activities were studied in the Ejin Sub-Basin of the Inner Mongolia Autonomous Region, china, to understand the groundwater evolution, to identify the predominant geochemical processes taking place along the horizontal groundwater flow path, and to characterize anthropogenic factors affecting the groundwater environment based on previous data. The concentrations of major ions and total dissolved solids （TDS） in the groundwater showed a great variation, with 62.5% of the samples being brackish （TDS ≥ 1 000 mg L^-l）. The groundwater system showed a gradual hydro-chemical zonation composed of Na^＋ -HCO3.-, Na^＋ -Mg^2＋ -SO4 ^2 -Cl^-, and Na^＋ -Cl^-. The relationships among the dissolved species allowed identification of the origin of solutes and the processes that generated the observed water compositions. The dissolution of halite, dolomite, and 2- gypsum explained, in part, the presence of Na^＋, K^＋, Cl^-, SO^4 , and Ca^2＋, but other processes, such as mixing, Na^＋ exchange for Ca^2＋ and Mg^2＋, and calcite precipitation also contributed to the composition of water. Human activity, in particular large-scale water resources development associated with dramatic population growth in the last 50 years, has led to tremendous changes in the groundwater regime, which reflected in surface water runoff change, decline of groundwater table and degeneration of surface water and groundwater quality. Solving these largely anthropogenic problems requires concerted, massive and long-term efforts.

关键词： Ejin Sub-Basin groundwater quality Heihe River human impact water resources development

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Growth and Microstructure of r.f. Sputtered Fe/Ti Multilayers

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Journal of Materials Science & Technology 2001年第5期17卷 521-524页

作者： Wei WANG Shenyang National Laboratory for Materials Science, institute of Metal research, chinese academy of sciences, Shenyang 110016,{3. Lishi WEN Department of Surface engineering of Materials, institute of Metal research, chinese academy of Science chinese Acad Sci Inst Mat Res Shenyang Natl Lab Mat Sci Shenyang 110016 Peoples R China chinese Acad Sci Inst Mat Res Dept Surface Engn Mat Shenyang 110016 Peoples R China

Fe/Ti multilayers with different modulation wavelengths (Lambda) prepared by r.f. sputtering has been investigated by using cross sectional transmission electron microscopy (XTEM). It was observed that the columnar structure, interface morphology, and metastable phase presented at the interface of the multilayer system strongly depend on the bilayer thickness (Lambda). For high period multilayers, the waviness wavelength of interfaces is about two times broader than the column diameter. For a sample with Lambda =3. nm, its column width and waviness wavelength was about 80, and 190 nm, respectively. Both of them decreased with the reduction of Lambda, so as to nearly equal values of column diameter and waviness wavelength were obtained. The Fe and Ti grains of both 3. nm and 6 nm multilayers are polycrystalline, and have a textured structure. In short bilayer thickness (Lambda =6 nm), the intermetallic compound Fe2Ti was presented at the interfaces due to solid state reaction; for Lambda =2 nm, amorphous phase Ti-rich layer was formed at the interfaces, resulting in a sharp interface multilayer structure.

关键词： Ti Growth and Microstructure of r.f Sputtered Fe/Ti Multilayers Fe

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A new approach of cascade utilization of the chemical energy of fuel

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Progress in Natural Science:Materials International 2006年第5期16卷 518-523页

作者： HAN Wei, JIN Hongguang and LIN Rumou ( institute of engineering Thermophysics, chinese academy of sciences, Beijing 100080,{3. Graduate School of the chinese academy of sciences, Beijing 100080,{3.) [a]institute of engineering Thermophysics Chinese Academy of Sciences Beijing China [b]Graduate School of the chinese academy of sciences Beijing China

The indirect release of chemical energy of fuel is investigated, and a new mechanism is proposed to identify the cascade utilization of chemical energy of fuel more clearly. Based on the concept of energy level, the internal phenomenon of the indirect chemical energy release is disclosed, and the equations of energy level describing the utilization of chemical energy and thermal energy during the indirect chemical energy release process are obtained. From theoretical analysis, we find that the superiority of the indirect chemical energy release of fuel comes from the cascade utilization of the fuel's chemical energy. Moreover, the cascade utilization of chemical energy is verified by the investigation of CRGT (chemically recuperated gas turbine). As a result, the thermal exergy obtained from the chemical energy release of fuel increases by 2 % -3.% . The results obtained here may help a deeper understanding of indirect chemical energy release of fuel and provide a theoretical basis for the synthesis of innovative energy systems.

关键词： chemically recuperated gas turbine methane/steam reforming chemical energy level cascade utilization.

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Origin of summer monsoon rainfall identified by δ18O inprecipitation

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Science Bulletin 2005年第23期50卷 2761-2764页

作者： PANG Hongxi1, HE Yuanqing1, 2, ZHANG Zhonglin1, LU Aigang1, GU Juan1 & ZHAO Jingdong1 1. Key Laboratory of Cryosphere and Environment, cold and arid Re-gions Environmental and engineering {3. institute, chinese academy of sciences, lanzhou 73.000, china 2. institute of Tibetan Plateau {3., chinese academy of sciences, Beijing 100085, china Key Laboratory of Cryosphere and Environment Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

A negative correlation between δ 18O in mon-soon precipitation and f, the ratio of precipitable water in monsoon region to that in water source area, is hypothesized. Using the Rayleigh model, a new method for identifying ori-gin of summer monsoon rainfall is developed based on the hypothesis. In order to validate the method, the isotopic data at New Delhi, a typical station in the southwest monsoon region, and Hong Kong, a typical station in the southeast monsoon region, were collected and analyzed for case studies. The case studies indicate that the water source areas of the monsoon rainfall at the two stations identified by the method are accordant with the general atmosphere circulation pat-terns. The method developed in this paper is significantly important for tracing the origin of summer monsoon pre-cipitation.

关键词： monsoon stable isotopes origin of monsoon precipita-tion.

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