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Valuations on arithmetic surfaces

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Science china Mathematics 2009年第1期52卷 66-76页

作者： XU Ning Department of Mathematics, g.aduate school of{2., beijing 100049, china Department of Mathematics Graduate School of Chinese Academy of Sciences Beijing China

In this paper, we give the definition of the height of a valuation and the definition of the big field ? p,g , where p is a prime and g ? ? is an additive subgroup containing 1. We conclude that ? p,g is a field and ? p,g is algebraically closed. Based on this the author obtains the complete classification of valuations on arithmetic surfaces. Furthermore, for any m ? p,g n ∈ ?, let V m,n be an ∝-vector space of dimension n - m + 1, whose coordinates are indexed from m to n. We generalize the definition of ? p,g , where p is a prime and g ? V m,n is an additive subgroup containing 1. We also conclude that ? p,g is a field if m ? 0 ? n.

关键词： valuation height rank totally ordered group big field transcendental number 14J10

A note on the tree decompositions of graphs

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chinese Science Bulletin 1997年第23期42卷 1948-1952页

作者： SHI MinyongInstitute of Software, chinese academy of sciences, beijing 100080,{2. Institute of Software Chinese Academy of Sciences Beijing China

IN this note all graphs are undirected, finite and simple. For a subgraph H of g,ε（H） andμ（H） denote the number of edges in H and the number of cycles in H respectively. H[X]denotes the subgraph of H induced by X. given two disjoint subsets X and Y of V（g）, wewrite Eg（X, Y）={xy∈E（g）|x∈X, y∈Y}. Sometimes Eg（H, Y）=Eg（V（H）,Y） is used for a subgraph H of g-Y. If T is a tree of g and e=uv∈g-E（T）with{u,v}V（T）, then T + e contains a unique cycle, denoted by C（T, e）.A tree-decomposition {T1, T2./sub>, …, Tk} of a graph g is a partition of E （g）, say,E（g）=E1 U E2./sub> U…U Ek, such that for each i with 1≤i≤k, Ti=g[Ei] is a tree.

关键词： tree decomposition singular vertex maximal planar bipartite graph.

Effects of diatoms on reproduction and growth of marine copepods

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Progress in Natural Science:Materials International 2004年第10期14卷 1-7页

作者： ZHANg guangtao 1,2. and SUN Song 1 (1.Key Laboratory of Marine Ecology&Environment sciences,Institute of Oceanology,chinese {2. of sciences,Qingdao2.6071,china 2.g.aduate school,chinese {2. of sciences,beijing100039,china) Key Laboratory of Marine Ecology & Environment sciences Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China. g.aduate school Chinese Academy of Sciences Beijing 100039 China

Two hot spots in marine ecology,deleterious effects of diatoms and feeding selectivity of copepods,as well as new progress on these two issues achieved in the recent ten years,are *** two issues are considered correlated *** and their metabolites can induce deleterious effects on growth,reproduction and development of copepods,including increase of mortality and decrease of egg production,hatching and growth *** negative effects,resulting from either chemical toxin or nutritional defi-ciency,can be conquered in natural environments by diverse *** is therefore concluded that deleterious effects of diatoms observed in laboratory or during blooming period are only a special case that accommodation of feeding strategy of copepods is *** under-stand their feeding strategy in natural environments is a prerequisite to explaining the mechanisms of deleterious effects caused by diatoms,and makes it possible to re-evaluate the energy flow in marine ecosystems.

关键词： diatoms copepod feeding strategy reproduction deleterious effects

Tree　ring　analysis　for　determination　of　pollution　history　of　Chengde　City，north　china

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Journal of Environmental sciences 1996年第1期8卷 77-85页

作者： Jiang gaoming(Institute of Botany, chinese academy of sciences,beijing 100044,{2. ) Inst Botany Chinese Acad of Sci Beijing China China

Air pollution history of sulphur and heavy metals since 1800 in Chengde City , north china,was studied by analyzing the concentrations of sulphur and heavy metals in growth rings of Pinus tabulaeformis Carr. Sulphur concentrations in the tree rings of 1910-192., 1970-1980,and 1980-1990 have increased 1-2., 3-5 and 10 times respectively as those in the tree ring of 1810-182. (Pggravation of industrialization, in the city of Chengde since 1950s. Fe appeared to increase during 192.-1940, possibly due to the opening of Damiao Iron Mine by the Japanese in 192.; Mn increased throughout the whole history, from 4. 1 μg/g(1840- 1850) to 10. 4 μg/g (1980 1990,P g the last 10 years by 560%(Pged little. The concentrations of sulphur and heavy metals in the tree rings at the beginning of 1800s were the lowest and could be regarded as the background *** calculated that S, Fe, Pb, Mn, Ni, and Zn in the tree rings have increased 10, 2.4,1.8,1.5,1.0 and 0. 8 times respectively during the past 190 years or so. The results showed that serious environmental pollution, especially air pollution of SO2.has occurred since 1949 when the People's Republic of china was founded.

关键词： tree rings Pinus tabulaeformis sulphur and heavy metals pollution history Chengde

genetic fingerprinting of plankton community provides new insights into aquatic ecology

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Progress in Natural Science:Materials International 2006年第9期16卷 893-898页

作者： YAN Qingyun, YU Yuhe and FENg Weisong ( Institute of Hydrobiology, chinese academy of sciences, Wuhan 430072. china {2. school of the chinese academy of Sci-ences, beijing 100039, china) Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China g.aduate school of the{2. Beijing 100039 China

Over the past two decades, molecular techniques have been widely used in ecological study and molecular ecology has been one of the most important branches of ecology. Meanwhile, genetic fingerprinting analyses have significantly enhanced our knowledge of the diversity and evolutionary relations of the planktonic organisms. Compared with conventional approaches in ecological study (e.g. morphological classification), genetic fingerprinting techniques are simpler and much more effective. This review provides an overview of the principles, advantages and limitations of the commonly used DNA fingerprinting techniques in plankton research. The aim of this overview is to assess where we have been, where we are now and what the future holds for solving aquatic ecological problems with molecular-level information.

关键词： genetic fingerprinting plankton community aquatic ecology genetic diversity.

Formal analysis and design of multi-party fair exchange protocols

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Science in china(Series F) 2006年第2期49卷 155-174页

作者： QINg Sihan1,2.3 & LI gaicheng1,3 1. Engineering Research Center for Information Security Technology, Institute of Software, chinese academy of sciences, beijing 100080,{2. 2. beijing Zhongke Ansheng Corporation of Information Technology, beijing 100080,{2. 3. g.aduate school of the chinese academy of sciences, beijing 100039,{2. Engineering Research Center for Information Security Technology Institute of Software Chinese Academy of Sciences beijing Zhongke Ansheng Corporation of Information Technology g.aduate school of the{2.

Based on the origin of message items and channel combination between transacting parties, and events and relations among events, this paper presents a concise, precise, and hierarchical model for general fair exchange protocols, formally specifies various security requirements which are able to reflect inherent requirements for fair exchange protocols more rigorously, and partition these security requirements with fine granularity. This work helps analyze, debug, and design multi-party fair exchange protocols more effectively and elaborately,

关键词： fair exchange logical protocol formal model security requirement.

Euler solution using adaptive Cartesian grid with a gridless boundary treatment

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Acta Mechanica Sinica 2009年第2期25卷 187-196页

作者： L. Xiang g. Yang LHD of Institute of Mechanics, chinese academy of sciences, 100190 beijing,{2. LHD of Institute of Mechanics Chinese Academy of Sciences Beijing China

A quadtree-based adaptive Cartesian grid generator and flow solver were developed. The grid adaptation based on pressure or density gradient was performed and a gridless method based on the least-square fashion was used to treat the wall surface boundary condition, which is generally difficult to be handled for the common Cartesian grid. First, to validate the technique of grid adaptation, the benchmarks over a forward-facing step and double Mach reflection were computed. Second, the flows over the NACA 0012.airfoil and a two-element airfoil were calculated to validate the developed gridless method. The computational results indi- cate the developed method is reasonable for complex flows.

关键词： Cartesian grid gridless method Adaptation technique Euler solution

A new iguanodontid (Jin-zhousaurus yangi *** ***.) from the Yixian Formation of western Liaoning,china

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chinese Science Bulletin 2001年第19期46卷 1669-1672页

作者： WANg Xiaolin & XU Xing1. Institute of Vertebrate Paleontology and Paleoanthropology, chinese academy of sciences, beijing 100044,{2. 2. College of Earth sciences and Resources,{2. University of geo-sciences, beijing 100083,{2. Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing China College of Earth sciences and Resources China University of Geosciences Beijing China

A new iguanodontid, Jinzhousaurus yangi gen. et sp. nov., is erected based on the cranial and dental morphology of a specimen from the Yixian Formation of western Liaoning. Although a few primitive characteristics remain, Jinzhousaurus yangi display a number of characteristics similar to those seen in derived iguanodontids. Other interesting characteristics include the absence of antorbital fenestra and the frontal excluded from the participation in orbit, which are closer to the condition in hadrosaurids. The unusual combination of the characteristics provides important data for assessing morphological evolution toward hadrosaurs. The new discovery also represents the first reported large-sized dinosaur from Jehol fauna in western Liaoning, and increases the diversity of this famous fauna. Furthermore, the discovery of a derived iguanodontid from the Yixian Formation provides further evidence supporting a Cretaceous age of the Jehol fauna, which is consistent with an isotopic age.

关键词： Western Liaoning Lower Cretaceous Yixian Formation Jehol Biota Iguanodontid

Cleaning of Chromate Manufacture Process

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International Journal of Minerals,Metallurgy and Materials 2000年第2期14卷 132-134页

作者： Xing Zou Yi Zhang(Applied Science school, University of Science and Technology beijing, beijing 100083, china)(Institute of Engineering Chemistry and Metallurgy, chinese academy of sciences, beijing 100080, china) Applied Science school University of Science and Technology Beijing Beijing 100083 China Institute of Engineering Chemistry and Metallurgy Chinese Academy of Sciences Beijing 100080 China

Sodium chromate solubility is determined in the range of NaOH concentrations from 450 to 810 g/L andsolution temperatUres from 30 to 110℃. The optimized conditions to separate sodium chromate from NaOH inleached solution are resolved. It is first found the method to efficiently separate sbdium chromate from NaOH andsodium altuninate in crude sodium chromate. Bench-scale studies on the separating are performed. Finally, goodseparation results are achieved.

关键词： chromate separation clean process