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Reinvestigation of the Henry's law constant for hydrogen peroxide with temperature and acidity variation

Journal of Environmental sciences 2010年第4期22卷 570-574页

作者： Daoming Huang,Zhongming Chen The State Key Laboratory of Environmental Simulation and Pollution Control,college of Environmental sciences and Engineering,peking university,beijing 100871,china. The State Key Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and Engineering Peking University Beijing 100871 China

Hydrogen peroxide is not only an important oxidant in itself; it also serves as both sink and temporary reservoir for other important oxidants including HOx （OH and HO2） radicals and O3 in the atmosphere. Its partitioning between gas and aqueous phases in the atmosphere, usually described by its Henry＇s law constant （KH）, significantly influences its role in atmospheric processes. Large discrepancies between the KH values reported in previous work, however, have created uncertainty for atmospheric modelers. Based on our newly developed online instrumentation, we have re-determined the temperature and acidity dependence of KH for hydrogen peroxide at an air pressure of （0.960 ± 0.013） atm （1 atm = 1.01325 × 10^5 Pa）. The results indicated that the temperature dependence of KH for hydrogen peroxide fits to the Van＇t Hoff equation form, expressed as lnKH = a/T - b, and a = -△H/R, where KH is in M/atm （M is mol/L）, T is in degrees Kelvin, R is the ideal gas constant, and AH is the standard heat of solution. For acidity dependence, results demonstrated that the KH value of hydrogen peroxide appeared to have no obvious dependence on decreasing pH level （from pH 7 to pH 1）. Combining the dependence of both temperature and acidity, the obtained a and b were 7024 ± 138 and 11.97 ± 0.48, respectively, AH was （58.40 ± 1.15） kJ/（***）, and the uncertainties represent σ. Our determined KH values for hydrogen peroxide will therefore be of great use in atmospheric models.

关键词： hydrogen peroxide Henry's law constant atmosphere acidity

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Environmental regulatory and policy framework in china: an overview

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Journal of Environmental sciences 2001年第1期13卷 122-128页

作者： ZHANG Shi qiu (Center for Environmental sciences, peking university, beijing 100871, china. E mail: zhangshq@***) 北京大学北京 100871

china has developed one of the most comprehensive environmental regulatory and policy framework in the world. This paper provides a description of the main institutions for environmental management in china, and overv... 详细信息

关键词： Laws and legislation Public policy Regulatory compliance Societies and institutions

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Real solution isolation with multiplicity of zero-dimensional triangular systems

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Science china(Information sciences) 2011年第1期54卷 60-69页

作者： ZHANG ZhiHai,FANG Tian & XIA BiCan LMAM,School of Mathematical sciences,peking university,beijing 100871,china LMAM School of Mathematical Sciences Peking University Beijing China

Existing algorithms for isolating real solutions of zero-dimensional polynomial systems do not compute the multiplicities of the *** this paper,we define in a natural way the multiplicity of solutions of zero-dimensional triangular polynomial systems and prove that our definition is equivalent to the classical definition of local(intersection)*** we present an effective and complete algorithm for isolating real solutions with multiplicities of zero-dimensional triangular polynomial systems using our definition. The algorithm is based on interval arithmetic and square-free factorization of polynomials with real algebraic *** computational results on some examples from the literature are presented.

关键词： real solution isolation local multiplicity local ring polynomial system solving

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Development of tourism resources and environment conservation in china: with special reference to Taishan Mountain

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Journal of Environmental sciences 1991年第3期3卷 99-104页

作者： Liu JihanDepartment of Geography,peking university,beijing 100871,china

By analyzing the cases in Taishan Mountain, Shandong Province and other tourist sites in china, this paper pointed out the problems in tourism management, such as resources damage, environment pollution, which are the result of tourism development, and are obstacles to the development. The paper also gave suggestion and practical ways to preserve tourism resources and environment.

关键词： tourism resources environment conservation Taishan Mountain tourism development.

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Density-functional formula for strongly correlated systems

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Progress in Natural Science:Materials International 2005年第5期15卷 395-401页

作者： WANG Huaiyu1*, HAN Rushan2 and CHEN Nanxian1(1. Department of Physics, Tsinghua university, beijing 100084, china 2. Department of Physics, peking university, beijing 100871, china) Dept. of Phys. Tsinghua Univ. Beijing 100084 China Dept. of Phys. Peking Univ. Beijing 100871 China

Density functional method is applied for strongly correlated systems. Based on the assumption that the systems are composed of electrons in singly-occupied orbitals and those in doubly-occupied orbitals, a set of self-consistent equations are obtained by standard variation procedure. The equations consist of two parts. One part is to solve the wave functions of the electrons in singly-occupied orbitals and the other is to solve the wave functions of the electrons in doubly-occupied orbitals. The physical meanings of the terms appearing in the equations are discussed.

关键词： density-functional theory strongly correlated systems doubly-occupied orbital two-particle wave function self-consistent equations.

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On the boundary value problem for harmonic maps of the Poincaré disc

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Chinese Science Bulletin 1997年第24期42卷 2025-2045页

作者： LI ZhongDepartment of Mathematics, peking university, beijing 100871, china Department of Mathematics Peking University Beijing China

The boundary value problem for harmonic maps of the Poincare disc is discussed. The emphasis is on the non-smoothness of the given boundary values in the problem. Let T . be a subspace of the universal Teichmüller space, defined as a set of normalized quasisymmetric homeomorphisms h of the unit circle S onto itself where h admits a quasiconformal extension to the unit disc D with a complex dilatation μ satisfyingwhere ρ(z)|dz|2 is the Poincare metric of D. Let B . be a Banach space consisting of holomorphic quadratic differentials φ in D with normsIt is shown that for any given quasisymmetric homeomorphism h : S1→S1∈ T . , there is a unique quasiconformal harmonic map of D with respect to the Poincare metric whose boundary corresponding is h and the Hopf differential of such a harmonic map belongs to B .

关键词： Harmonic maps quasiconfomial mappings universal Teichmüller spaces.

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The toxicity of Cu^(2+) to Microcystis aeruginosa using dielectric spectroscopy

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Science china Chemistry 2010年第3期53卷 631-636页

作者： YU YanLi1,BAI Wei1,ZHAO KongShuang1& ZHOU YunLong2 1college of Chemistry,beijing Normal university,beijing 100875,china 2college of life Science,beijing Normal university,beijing 100875,china college of Chemistry Beijing Normal University Beijing China college of life Science Beijing Normal University Beijing China

Dielectric spectroscopy(DS) was utilized to investigate the toxicity of the Cu2+ solution to Microcystis *** was found that 0.04 mM Cu2+ had no effect on dielectric increment,whereas the Cu2+ concentrations above 0.1 mM decreased the value of Δε/Δε *** toxic effect of Cu2+ on *** cells was time-dependent and *** was a threshold concentration between 0.04 mM and 0.1 mM,which affected the cell membrane,suggesting that Cu2+ at the concentrations higher than 0.1 mM caused serious plasmalemma damage to *** *** addition of 1 mM Ca2+ or Mg2+ did not protect *** cells from 1 mM Cu2+ *** study demonstrates that DS monitors cell biomass facilitating observation of the toxic effects of metal ions.

关键词： Microcystis aeruginosa dielectric spectroscopy dielectric increment cupric ion toxicity

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Oblique Derivative Problems for Second OrderNonlinear Equations of Mixed Type inMultiply Connected Domains

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Communications in Nonlinear Science and Numerical Simulation 1999年第4期4卷 281-284页

作者： Guochun WEN(Department of Mathematics, peking university, beijing 100871, china) Department of Mathematics Peking University Beijing 100871 China

1FormulationoftheProblemLetDbeNconnectedboundeddomaininthecomplexplaneCwiththeboundaryNZNOD=WUL,wherer=ZrjEn（00},L=ULi’andrhastheendj=1j=1poiatsal=02,LiaredeadedasLI={x=;)05x51}L:={x=--y+hi,hi... 详细信息

关键词： oblique derivative problems quasinonlinear equations of mixed type mul-tiply connected domains.

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Polycistronic strategy for cyanobacterial expression vector construction: Co-transcription of a human gene and a selective marker gene

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Progress in Natural Science:Materials International 2005年第9期15卷 798-803页

作者： ZHANG Yukun1, SHI Dingji2, ZHAO Feifei1, YU Meimin1 and RU Binggen1(1. college of life Science, peking university, beijing 100871, china 2. college of Marine sciences & Engineering, Tianjin university of Science & Technology, Tianjin 300450, china) college of life Science Peking University Beijing 100871 China college of Marine sciences and Engineering Tianjin University of Science and Technology Tianjin 300450 China

A polycistronic expression vector, pKGA-NTF1, was constructed for the cyanobacterium. Within this vector, the spectinomycin/streptomycin resistance gene (aadA) facilitated the selection of transformants when co-transcribed with favorite genes. A natural glnA gene was selected as the platform to introduce the plasmid into a neutral site of the Synechococcus sp. PCC 7002 chromosome. Function of the vector was demonstrated by the insertion of a modified human Trefoil factor 3 gene (NTF1) to upstream of the aadA gene and by the analyses of the transformed strains. Antibiotics resistance assays showed that the dicistronic expression cassette conferred high spectinomycin resistance to both the E. coli cells and the Synechococcus cells. PCR analysis and Western-blot analysis were carried out to confirm the integration and expression of the NTF1 gene, respectively. Through simple molecular manipulations, the artificial polycistronic structure described here can be conveniently used to express other favorable genes or operons in cyanobacteria, and to study the cyanobacterial gene expression as well.

关键词： cyanobacterial transformation human Trefoil factor 3 polycistronic expression Synechococcus sp. PCC 7002 vector construction.

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Contributions of different land cover types in Otindag Sandy Land and Bashang area of Hebei Province to the material source of sand stormy weather in beijing

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Chinese Science Bulletin 2003年第17期48卷 1853-1856页

作者： LIU Hongyan, TIAN Yuhong & DING Deng Department of Ecology, college of Environmental sciences, peking university, beijing 100871, china Department of Ecology College of Environmental Sciences Peking University Beijing 100871 China

Different land cover types in Otindag Sandy Land and Bashang area of Hebei Province are linked to a material source of sand stormy weather in beijing based on results of field vegetation and soil survey and laboratory works. Results of grain size analysis show that dust release potential in per unit area of moving sandy land is small, while lowland meadow and meadow steppe in stony hills have high potential of releasing dusts in per unit area during sand stormy weather occurrence. Further considering the effects of vegetation, it is inferred that the moving sandy land served as a material source of past dust storm and the possi-bility of dust release in per unit area is low in current time. Typical steppe in stony hills is undergoing desertification and its dust release possibility in per unit area is high. Farmland has strong potential of release dusts when they are ploughed in spring, but a large amount of therophytes grow and thus prevent dusts from release when cultivation was terminated. Potentials of dust release in per unit area in fixed sand dunes, stony mountain meadow steppe and lowland meadow are low due to high cover of perennials. Sand dune reactivation and desiccation of lakes and lowlands under estimated future climatic change will make them serve as a future material source of sand stormy weather.

关键词：河北北京沙暴土地覆盖砂地坝上地区材料源

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