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Helium isotope investigation on magnetic reversal boundaries of loess-paleosol sequence at Luochuan, central Chinese Loess Plateau

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Chinese Science Bulletin 2007年第17期52卷 2407-2412页

作者： DU XueQing1,6, WANG YongHong2, REN JianGuo3, YE XianRen4.& LU HuaYu5,1 1 State Key laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of sciences, Xi’an 710075, china 2 College of Marine geosciences, Ocean {4. of china, Qingdao 266003, china 3 National Natural Science Foundation of china, Beijing 100085, china 4.Lanzhou Research Center for Petroleum and Natural Gas Resources, Institute of Geology and Geophysics, Chinese Academy of sciences, Lanzhou 730000, china 5 Key laboratory of Coast and Island Development, School of Geographic and Oceanographic sciences, Nanjing {4., Nanjing 210093, china 6 Graduate {4. of Chinese Academy of sciences, Beijing 10004., china State Key laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi''an 710075 China

Extraterrestrial particles have higher 3He/4.e ratios than those of terrestrial sediments ( > 100 Ra versus < 0.03 Ra, where Ra is the 3He/4.e ratio normalized to the atmospheric value of 1.4.10?6). The inter- planet... 详细信息

Extraterrestrial particles have higher 3He/4.e ratios than those of terrestrial sediments ( > 100 Ra versus 4.e ratio normalized to the atmospheric value of 1.4.10?6). The inter- planetary dust particles (IDPs), which are very rich in 3He, continuously bombard the Earth and can accumulate in deposits. IDPs sedimentation rate changes can significantly influence 3He concentration in the Earth surface sediments. Since IDPs are not easy to detect in terrestrial deposits, measuring helium isotopes is a helpful approach to examine changes in IDPs. Helium concentration and helium isotopic composition magnetic substances and the quartz particles were examined for helium concen- tration and helium isotopic ratio. Results show that the 3He/4.e ratio and the 3He concentrations of the magnetic substances are clearly higher than those of the bulk samples and the quartz particles, and, the 3He/4.e ratio of the extracted magnetic substances is also higher than that of the average level of the Earth’s crust. The higher helium content in the magnetic fractions can be explained by an influx of IDPs.

关键词：中国黄土高原古土壤氦同位素行星际尘埃颗粒反方向磁化

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china's energy, environment and policy perspective

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Journal of environmental sciences 2000年第3期12卷 270-274页

作者： ZHANG Shi\|qiu (Center for environmental sciences, Peking university, Beijing 100871, china) Center for environmental sciences Peking University Beijing 100871 China

This paper discusses the specific features of the energy in china, and addresses those key challenges in china is that the co\|exist of (1) higher total energy production and lower per capita level; (2) lower per capita energy resources level with unrational energy consumption structure; (3) lower energy utilization efficiency and higher energy conservation potential; and (4. unequal distribution of energy resources. It reviews the key environmental problems related to the feature of energy production and consumption. Based on the analysis, the author furthers addresses the policy and actions needed.

关键词： energy energy production energy consumption environment policy

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A HIGH-ORDER-ACCURATE DIFFERENCE SCHEME WITH UNCONDITIONAL STABILITY FOR THE DIFFUSION EQUATION ON NONUNIFORM GRIDS

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Journal of Hydrodynamics 2001年第1期13卷 92-98页

作者： Wang Xuan, Yang Zhi-feng State Key laboratory of Environment Simulation and Pollution Control, Institute of environmental sciences, Beijing Normal university, Beijing 100875, {4.[WT5”HZ] Beijing Normal Univ. Beijing 100875 China

WT5”BZ]A high-order-accurate difference scheme with unconditional stability is developed for the diffusion equation on nonuniform grids. The theoretical analysis shows that the accuracy of this scheme is between third order and fourth order, and fourth-order accuracy is achieved in the case of the same grid steps being used within the computational domain. Two numerical examples are given to demonst ate the advantages of the proposed scheme. Compared with the conventional difference scheme, more accurate numerical solution can be obtained by using the proposed scheme even with relatively larger grid sizes. It is also pointed out that the appropriate structure of the nonuniform grid can not only make the proposed scheme more practical, but lead to a solution superior to that for a uniform grid structure. [WT5”HZ]

关键词： ]finite difference scheme diffusion equation nonuniform grid high accuracy computational fluid dynamics

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Three-dimensional decomposition method of global atmospheric circulation

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Science china Earth sciences 2008年第3期51卷 386-402页

作者： LIU HaiTao1,2,3, HU ShuJuan4. XU Ming5 & CHOU JiFan6,7 1 State Key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of sciences, Beijing 100029, china 2 Graduate {4. of Chinese Academy of sciences, Beijing 10004., china 3 Beijing Climate Center, Beijing 100089, china 4.Department of Mathematics, Lanzhou {4., Lanzhou 730000, china 5 Shanghai Typhoon Institute, Shanghai 200030, china 6 Department of Atmospheric sciences, Lanzhou {4., Lanzhou 730000, china 7 china Meteorological Administration Training Center, Beijing 100089, china 1. State Key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. Graduate university of Chinese Academy of sciences Beijing 100049 China 3. Beijing Climate Center Beijing 100089 China 4. Department of Mathematics Lanzhou University Lanzhou 730000 China 5. Shanghai Typhoon Institute Shanghai 200030 China 6. Department of Atmospheric sciences Lanzhou University Lanzhou 730000 China 7. china Meteorological Administration Training Center Beijing 100089 China

By adopting the idea of three-dimensional Walker, Hadley and Rossby stream functions, the global atmospheric circulation can be considered as the sum of three stream functions from a global perspective. Therefore, a m... 详细信息

关键词： three-dimensional decomposition of the global atmospheric circulation generalized Walker Hadley and Rossby stream functions existence and uniqueness vertical motion

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Multiparty simultaneous quantum identity authentication with secret sharing

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Science china(Physics,Mechanics & Astronomy) 2008年第3期51卷 321-327页

作者： YANG YuGuang1,2,WEN QiaoYan3 & ZHANG Xing4.5 1 College of Computer Science and Technology,Beijing university of Technology,Beijing 100022,china 2 State Key laboratory of Information Security (Graduate university of the Chinese Academy of {4.),Beijing 10004.,china 3 School of Science,Beijing university of Posts and Telecommunications,Beijing 100876,china 4.Institute of Electronic Technology,Information Engineering university,Zhengzhou 4.0004.china 5 Trusted Computing laboratory,Beijing university of Technology,Beijing 100022,china College of Computer Science Technology Beijing University of Technology Beijing 100022 China State Key laboratory of Information Security [Graduate university of the Chinese Academy of sciences] Beijing 100049 China School of Science Beijing University of Posts Telecommunications Beijing 100876 China Institute of Electronic Technology Information Engineering University Zhengzhou 450004 China Trusted Computing laboratory Beijing University of Technology Beijing 100022 China

Two multiparty simultaneous quantum identity authentication (MSQIA) protocols based on secret sharing are presented. All the users can be authenticated by a trusted third party (TTP) simultaneously. In the first protocol,the TTP shares a random key K with all the users using quantum secret sharing. The ith share acts as the authentication key of the ith user. When it is necessary to perform MSQIA,the TTP generates a random number R secretly and sends a sequence of single photons encoded with K and R to all the users. According to his share,each user performs the corresponding unitary operations on the single photon sequence sequentially. At last,the TTP can judge whether the impersonator exists. The sec-ond protocol is a modified version with a circular structure. The two protocols can be efficiently used for MSQIA in a network. They are feasible with current technol-ogy.

关键词： quantum identity authentication secret sharing quantum cryptography

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Land cover changes based on plant successions: Deforestation, rehabilitation and degeneration of forest in the upper Dadu River watershed

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Science china Earth sciences 2005年第12期48卷 2214-2230页

作者： YAN Jianzhong1,2,3, ZHANG Yili1, BAI Wanqi1, LIU Yanhua4. BAO Weikai5, LIU Linshan1, 2 & ZHENG Du1 1. Institute of Geographic sciences and Natural Resources Research, Chinese Academy of sciences, Beijing 100101, china 2. Graduate School of the Chinese Academy of sciences, Beijing 100039, china 3. College of Resources and Environment, Southwest Agricultural university, Chongqing 4.0716, china 4. The Ministry of Science and Technology, P. C. china, Beijing 100862, china 5. Chengdu Institute of Biology, Chinese Academy of sciences, Chengdu 61004., china 1. Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. Graduate School of the Chinese Academy of sciences 100039 Beijing China 3. College of Resources and Environment Southwest Agricultural University 400716 Chongqing China 4. The Ministry of Science and Technology P. C. China 100862 Beijing China 5. Chengdu Institute of Biology Chinese Academy of Sciences 610041 Chengdu China

To link regional land use/cover changes with environmental effects, land cover changes are required to reflect vegetation successions, whereas the land cover classification systems commonly used nowadays cannot serve this purpose. In this paper, a new land cover classification system is established in which land covers are classified by the vegetation succes-sions, taking Zamtang County, Barkam County and Jinchuan County in the upper Dadu River watershed as a study area. Using multi-temporal remote sensing images, the land cover data of 1967, 1986 and 2000 are obtained by means of integration of unsupervised classification and visual interpretation methods. The database facilitates the study of land use/cover changes, en-vironmental effects and ecological construction. Land cover changes reflect the main ecological processes in the upper Dadu River watershed. The landscape composed mainly of grasslands, wildwoods and alpine scrubs in 1967 was changed to that of grasslands, secondary forests, al-pine scrubs, fragmentary wildwoods, artificial forests, secondary scrubs in 2000, meanwhile, the landscape got more fragmentized. The total area of the forests decreased by 9.4.%. Study results have shown the process of restoration of logged areas in forest centers. From 1967 to 2000, only 6.86 percents of logged areas were converted to shrubs, meadows or crop-lands, and the rest were converted into artificial forests or secondary forests. So the ecological shelter functions will be restored, stage by stage. Firewood collection, charcoal production and overgrazing are the three major triggers for the extensive degradation of alpine oak forests, Sa-bina tibetica forests and meadows. The arid valley grasslands expanded too. The degradation of vegetation in the southern slopes impairs ecological shelter functions and affects livelihood of local residents, so it is essential to find effective measures for ecological restoration and recon-struction. Field investigations have found

关键词： land use/cover classification, upper Dadu River watershed, vegetation successions, GIS, RS.

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Experimental remolding on the caprock's 3D strain field of the Indosinian-Yanshanian epoch in Tongling deposit concentrating area

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Science china Earth sciences 2005年第7期48卷 863-874页

作者： DENG Jun1,HUANG Dinghua2,WANG Qingfei1,WAN Li1,SUN Zhongshi3,YANG Liqiang1 & GAO Bangfei1 1. State Key laboratory of Geological Processes and Mineral Resources,china university of geosciences,Beijing 100083,china 2. Faculty of Earth sciences,china university of geosciences,Wuhan 4.0074.china 3. Department of Earth sciences,Jilin university,Changchun 130061,china State Key laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China Faculty of Earth sciences China University of Geosciences Wuhan 430074 China Department of Earth sciences Jilin University Changchun 130061 China

Based on field observations and rheology analysis, we perform one analogue experiment and remold the 3D structural frame of Tongling deposit concentrating area firstly. Then we disassemble and dialyze the 3D structures of the model using the methods of "slicing" and "stripping". A series of sliced planes vertical to the fold hinges show similar landscapes of that in the drill hole profiles. Meanwhile, layer stripping analysis indicates that the deformation features of each layer in the model are qualitatively analogical to those obtained from field observations. Through contrasting the 3D structure between the experimental model and the field phenomena, we verify the following 3D deformation features of the caprock in this area: (1) the Tongling area mainly consists of three series of NE S-typed fold groups; (2) in the uniform stress field, the incoherent folds universally develop in different positions, along different axes as well as in different strata; (3) the faults propagate upward which are mostly inter-bedded detachment faults, while the fold amplitudes decrease while going deeper; and (4. the folds and cleavages are highly developed in the Silurian System indicating that the deformation effect of the Indosin-ian-Yanshanian structural layer terminates at this layer, which suggests that the Silurian System is the crucial layer for the inversion between brittle and plastic deformation domains and the underlying strata are subject to the control of another deformation system with distinct properties.

关键词： Tongling deposit concentrating area Indosinian-Yanshanian epoch 3D structural frame of the caprock analogue experiment slicing and stripping analysis structural model.

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Sorption behavior of U(VI), ^(234.U(VI) and ^(238)U(VI) onto fracture-filling clays in Beishan granite, Gansu: Application to selecting the site of high-level radwaste repository in china

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Science china Earth sciences 2005年第10期48卷 1649-1655页

作者： MIN Maozhong1,2, LUO Xingzhang3, WANG Ju4. JIN Yuanxin4.& WANG Rucheng1 1. Department of Earth sciences, State Key laboratory of Mineral Deposit Research, Nanjing university, Nanjing 210093, china 2. Center of Materials Analysis, Nanjing university, Nanjing 210093, china 3. Department of environmental Science and Engineering, Nanjing university, Nanjing 210093, china 4. Beijing Geology Institute, Nuclear Industry, Beijing 100029, china Department of Earth sciences State Key Laboratory of Mineral Deposit Research Nanjing University Nanjing China Center of Materials Analysis Nanjing university Nanjing china Department of environmental Science and Engineering Nanjing university Nanjing china Beijing Geology Institute Nuclear Industry Beijing china

The first results of sorption experiments of U(VI), 234.(VI) and 238U(VI) onto original (unpurified) fracture-filling clays from No.1 monzonitic granite intrusion, Beishan area, Gansu Province, china are reported. The monzonitic granite intrusion is a potential location for a high-level radwaste (HLW) repository in china. The present experimental results show that the maximum U(VI) sorption reached 92% at near-neutral pH and the distribution coefficient (Kd) was 1226 mL/g. A high sorption capacity of the fracture-filling clays in host rock on radioactive ele-ments is necessary for HLW deep geological disposal repository. No preferential sorption of 234. onto the clays was found. Finally, the sorption of U(VI) onto the clays was also modeled using a surface complexation model.

关键词： HLW geological disposal repository, granite, uranium, radionuclide, clay, sorption.

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Distribution and origin of biologically available phosphorus in the water of the Meiliang Bay in summer

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Science china Earth sciences 2006年第z1期49卷 146-153页

作者： HUANG Qinghui, WANG Zijian, WANG Donghong, MA Mei & WANG Chunxia State Key laboratory of environmental Aquatic Chemistry, Research Center for Eco-environmental sciences, Chinese Academy of sciences, Beijing 100085, china Key laboratory of Yangtze Aquatic Environment (Ministry of Education), College of environmental Science and Engineering, Tongji university, Shanghai 200092, china Chinese Acad Sci Ecoenvironm Sci Res Ctr State Key Lab Environm Aquat Chem Beijing 100085 Peoples R China Tongji Univ Coll Environm Sci & Engn Minist Educ Key Lab Yangtze Aquat Environm Shanghai 200092 Peoples R China

The investigation and continuous monitoring with an innovative iron oxide embedded cellulose acetate membrane (FeO/CAM) on the concentrations of biologically available phosphorus (BAP) were conducted in the Meiliang Bay of the Taihu Lake during summer in 2004. The results showed that the concentrations of dissolved (FeO-DP), particulate (FeO-PP) and total bioavailable phosphorus (FeO-P) had similar horizontal distribution. The BAP concentrations were the highest in those estuaries in the northern bay. With the decrease of the distance to the estuary or long shore,there was little difference between BAP concentrations in an open lake area. During the observation period, algal blooms occurred in most waters of the northern bay, which was reflected from the high concentrations of chlorophyll a (Chl-a). While they were not highest in the estuarine waters of those major rivers, this is the case for the BAP concentrations. The concentrations of Chl-a had a significantly positive correlation with those of bioavailable phosphorus in the open area of the Meiliang *** the sediment resuspension induced by wind and wave, BAP concentrations increased in a short-term, indicating that the riverine P inputs mainly contribute to the concentrations of BAP in the estuarine water while internal P release was the major source of BAP in the open lake area. In the eutrophic shallow lake, the blooms of alga may cause pH increase and further result in internal P release. The above results showed that the new membrane of FeO/CAM can be used to monitor the concentrations of BAP and provide the scientific justifications for the control strategy of the lake eutrophication.

关键词： phosphorus, bioavailability, eutrophication, resuspension, Taihu Lake.

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Status of study on biological and toxicological effects of nanoscale materials

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Science china Chemistry 2005年第5期48卷 385-394页

作者： WANG Bing1, FENG Weiyue1, ZHAO Yuliang1, XING Gengmei1, CHAI Zhifang1, WANG Haifang2 & JIA Guang3 1. laboratory for Bio-environmental health sciences of Nanoscale Materials (Nanosafety Lab), Institute of High Energy Physics, Chi-nese Academy of sciences, Beijing 10004., china 2. College of Chemistry and Molecular Engineering, Peking university, Beijing 100871, china 3. Department of Occupational and environmental health sciences, School of Public health, Peking university, Beijing 100083, china 1. laboratory for Bio-environmental health sciences of Nanoscale Materials (Nanosafety Lab) Institute of High Energy Physics Chinese Academy of Sciences 100049 Beijing China 2. College of Chemistry and Molecular Engineering Peking University 100871 Beijing China 3. Department of Occupational and environmental health sciences School of Public Health Peking University 100083 Beijing China

Because the physical and chemical properties of nanosized materials mostly differ from the existing microsized materials, their potential impacts on human health and the envi-ronment will be topics under the serious discussions in press and in a number of international scientific journals. We analyze and summarize the existing data of the experimental study on the biological activities and adverse effects of nanoscale materials/particles including single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron powders. Though some biological behaviors of nanoscale materials observed cannot be understood on the basis of the current knowledge, as the existing data are mostly preliminary, it is too early to make some ex-clusive conclusions on biological activities (or the toxicity) of any of nanoscale materials. The experimental techniques, the current topics, and the future research directions for this new re-search field are also discussed.

关键词： nanomaterials, single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron, biological activity and toxicological effect.

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