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Mixed uncertainty analysis of polycyclic aromatic hydrocarbon inhalation and risk assessment in ambient air of beijing

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Journal of Environmental Sciences 2008年第4期20卷 505-512页

作者： College of Environmental Sciences and Engineering, Peking University, beijing 100871, china GUO Huaicheng LIU Yong HUANG Kai WANG Zhen ZHAN Xinye 不详 School of Natural Resources and Environment University of Michigan Ann Arbor 48109 USA Department of Civil and Resource Engineering Dalhousie University Halifax NS B3JIZ1 Canada

This article presents the application of an integrated method that estimates the dispersion of polycyclic aromatic hydrocarbons （PAHs） in air, and assesses the human health risk associated with PAHs inhalation. An uncertainty analysis method consisting of three components were applied in this study, where the three components include a bootstrapping method for analyzing the whole process associated uncertainty, an inhalation rate （IR） representation for evaluating the total PAH inhalation risk for human health, and a normally distributed absorption fraction （AF） ranging from 0% to 100% to represent the absorption capability of PAHs in human body. Using this method, an integrated process was employed to assess the health risk of the residents in beijing, china, from inhaling PAHs in the air. The results indicate that the ambient air PAHs in beijing is an important contributor to human health impairment, although over 68% of residents seem to be safe from daily PAH carcinogenic inhalation. In general, the accumulated daily inhalation amount is relatively higher for male and children at 10 years old of age than for female and children at 6 years old. In 1997, about 1.73% cancer sufferers in beijing were more or less related to ambient air PAHs inhalation. At 95% confidence interval, approximately 272-309 individual cancer incidences can be attributed to PAHs pollution in the air. The probability of greater than 500 cancer occurrence is 15.3%. While the inhalation of ambient air PAHs was shown to be an important factor responsible for higher cancer occurrence in beijing, while the contribution might not be the most significant one.

关键词： polycyclic aromatic hydrocarbons (PAHs) uncertainty analysis human health risk

Determination of atmospheric concentrations of halocarbons in beijing area

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Journal of Environmental Sciences 1993年第1期5卷 76-82页

作者： Wang ShaobinResearch Center for Eco-Environmental Sciences, Chinese Academy of Sciences, beijing 100085, chinaPeng Lixin and Tang XiaoyanResearch Center of Environmental Sciences, Peking University, beijing 100871, china Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China. China

Gas chromatography with ambient temperature injection and frozen-trapped techniques was used to determine the atmospheric concentrations of halocarbons over beijing. Halogenated compounds such as CFC-11, CFC-12, CHCl_3, CCl_4, CH_3CCl_3, CHCl =CCl_2, and CCl2=CCl2 were measured and their concentrations are 109±8, 234±13, 47±22, 97±24, 88±29, 11±1 and 17±3 (pptv), respectively.

关键词： GC-ECD atmospheric halocarbons beijing.

INFINITE ELEMENT METHOD FOR THE EXTERIOR PROBLEMS OF THE HELMHOLTZ EQUATIONS

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Journal of Computational Mathematics 2000年第6期18卷 657-672页

作者： Lung-an Ying (School of Mathematical Sciences, Peking University, beijing 100871, china) 北京大学北京 100871

There are two cases of the exterior problems of the Helmholtz equation. If λ ≥ 0 the bilinear form is coercive, and if λ < 0 it is the scattering problem. We give a new approach of the infinite element method, which enables us to solve these exterior problems as well as corner problems. A numerical example of the scattering problem is given. [ABSTRACT FROM AUTHOR]

关键词： Helmholtz equation exterior problem infinite element method

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

THE FUNCTION d_k(n) AT CONSECUTIVE INTEGERS

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Chinese Annals of Mathematics,Series B 1999年第4期20卷 473-478页

作者： MENG ZAIZHAO(Department of Mathematics, Peking University, beijing 100871, china) Department of Mathematics Peking University Beijing 100871 China

Let dk(n) denote the k-fold iterated divisor function (k ≥ 2). It is proved that for sufficiently large x) dk(n) = dk(n + 1) holds for >> x(log log x)-3 integers n ≤x.

关键词： Divisor function Multiplicative function Congruence

Neuroimaging studies of self-reflection

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Progress in Natural Science:Materials International 2004年第4期14卷 10-16页

作者： ZHU Ying(Department of Psychology, Peking University, beijing 100871, china) Dept. of Psychology Peking Univ. Beijing 100871 China

This paper reviews some basic findings and methodological issues in neuroimaging studies of self-referential processing. As a general rule, making judgments about one’s self, inclusive of personality trait adjectives or current mental states (person’ s preferences, norms, aesthetic values and feeling) uniformly generates medial prefrontal activations, regardless of stimulus materials (words or pictures) and modality (visual or auditory). Cingulate activations are also observed in association with most self-referential processing. Methodological issues include treating self-referential processing as either representing one’s own personality traits or representing one’s own current mental states. Finally, self-referential processing could be considered as implement of "I think therefore I am" approach to neuroimaging the self.

关键词： self self-referential processing medial prefrontal cortex cingulate brain image.

BRILL-NOETHER MATRIX FOR RANK TWO VECTOR BUNDLES

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Chinese Annals of Mathematics,Series B 2002年第4期23卷 531-538页

作者： TAN XIAOJIANGSchool of Mathematical Sciences, Peking University, beijing 100871, china School of Mathematical Sciences Peking University Beijing 100871 China

Let X be an arbitrary smooth irreducible complex projective curve, E (?)X a rank two vector bundle generated by its sections. The author first represents ?as a triple {D1,D2,f}, where D1 , D2 are two effective divisors with d = deg(D1) + deg(D2), and f ∈ H?X, [D1] |D2) is a. collection of polynomials. E is the extension of [D2] by [D1] which is determined by f. By using / and the Brill-Noether matrix of D1+D2, the author constructs a 2g × d matrix WE whose zero space gives Im{H0(X,[D1]) (?) H0(X, [D1] |D1)}(?) Im{H?X, E) (?) H0(X,[D2]) (?) H0(X, [D2]|D2)} From this and H0(X,E) = H0(X,[D1]) (?)Im{H0(X,E) (?) H0(X, [D2])}, it is got in particular that dimH0(X, E) = deg(E) - rank(WE) + 2.

关键词： Brill-Noether matrix Vector bundle Effective divisor

DISTRIBUTION OF THE (0,∞) ACCUMULATIVE LINES OF MEROMORPHHIC FUNCTIONS

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Chinese Annals of Mathematics,Series B 1994年第4期15卷 453-462页

作者： WU SHENGJIAN(Department of Mathematics, beijing University,beijing 100871, china.) 北京大学数学系北京 100871

Suppose that f(z) is a meromorphic function of order and of lower order μin the plane. Let ρ be a positive number such that .(1) If f(l)(z) () has ρ() finite nonzero deficient values ai (i =1,…,p) with deficiencies δ(ai, f(l)), then f(z) has a (0, ∝) accumulative line of order inany angular domain whose vertex is at the origin and whose magnitude is larger than(2) If f(z) has only p ()(0, ∝) accumulative lines of order : arg z = θk (θ1<θ2…<θp<2π, θp+1 = θ1 + 2π), then , where , providedthat has a finite noasero deficient value.

关键词： Meromorphic function Accumulative line Order.

REGULARITY OF SOLUTIONS TO THE DIRICHLET PROBLEM FOR DEGENERATE ELLIPTIC EQUATION

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Chinese Annals of Mathematics,Series B 2003年第4期24卷 529-540页

作者： CHEN YEMIN School of Mathematics, Peking University, beijing 100871, china. School of Mathematics Peking University Beijing 100871 China

In this paper, the author studies the regularity of solutions to the Dirichlet problem forequation Lu = f, where L is a second order degenerate elliptic operator in divergence form inΩ, a bounded open subset of Rn (n... 详细信息

关键词： Regularity Dirichlet problem Degenerate Weighted spaces