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Modeling the impact of Australian Plate drift on Southern Hemisphere climate and environment

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Chinese Science Bulletin 2005年第14期50卷 1495-1502页

作者： ZHOU Botao1,5, ZHAO Ping2, JIAN Zhimin3 & HE Jinhai4.1. Nansen-Zhu International Research Center, Institute of atmospheric Physics, Chinese Academy of Sciences, beijing 100029, china 2. Institute of Climate and Environment, Chinese Academy of Meteoro- logical Sciences, beijing 100081, china 3. Laboratory of Marine Geology, Tongji university, Shanghai 200092, china 4. department of atmospheric Sciences, Nanjing Institute of Meteorol- ogy, Nanjing 21004., china 5. Graduate School of the Chinese Academy of Sciences, beijing 100039, china Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China Institute of Climate and Environment Chinese Academy of Meteorological Sciences Beijing 100081 China Laboratory of Marine Geology Tongji University Shanghai 200092 China department of atmospheric Sciences Nanjing Institute of Meteorology Nanjing 210044 China

Using a global atmosphere-ocean coupled model with the present-day and 14.MaB.P. oceanic topogra- phy respectively, two experiments are implemented to inves- tigate the effect of different locations of Australian Plate on the atmospheric circulation in middle-high latitudes of the Southern Hemisphere. The results show that when Austra- lian Plate lay south at 14.MaB.P., both anticyclone circula- tions in the subtropical oceans and cyclone circulation around 60°-70°S are strengthened. Subtropical highs and circumpolar low pressure appear stronger, which results in much stronger Antarctic Oscillation and shorter period of Antarctic Oscillation Index (AOI) at 14.MaB.P. The rainfall and the surface air temperature also change correspondingly. The precipitation decreases around 4.°S and increases around 60°-70°S, and the surface air temperature rises in high latitudes of the South Pacific and descends over the Weddell Sea and its north side. Besides, due to the changes of the temperatures and winds, Antarctic sea ice coverage also changes with its increasing in the Ross Sea and its west re- gions and decreasing in the Weddell Sea.

关键词：半球气候地球环球澳大利亚漂流物海洋地形学

COPOLYMERIZATION AND DETERMINATION OF MONOMER REACTIVITY RATIOS OF DL-LACTIDE WITH 3-BENZYLOXYMETHYL-1,4.DIOXANE-2,5-DIONE

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Chinese Journal of Polymer Science 2002年第5期20卷 413-417页

作者： Ji-yuan Yang Jian Yu Mei Li Zhong-wei Gu Xin-de Feng department of Polymer Science and Engineering peking university beijing 100871, china National Research Institute for Family Planning {4. 100081, china peking Univ Dept Polymer Sci & Engn Beijing 100871 Peoples R China Natl Res Inst Family Planning Beijing 100081 Peoples R China

The copolymerization of DL-LA and 3-BMG was carried out in bulk with stannous 2-ethythexanoate as the catalyst. A series of copolymers with pendant protected groups were obtained and characterized by H-1-NMR and GPC analysis. The monomer reactivity ratios were evaluated by the Fineman-Ross method and the Kelen-Tudos method and found to be r(BMG)=1.96 and r(LA)=0.37, respectively.

关键词： 3-benzyloxymethyl 1,4.dioxane-2,5-dione DL-lactide reactivity ratios

SOME NEW RESULTS ON THE CONFIDENCELIMITS FOR RELIABILITY PARAMETERS IN THECASE OF NO FAILURES

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Systems Science and Mathematical Sciences 1999年第1期12卷 70-81页

作者： SUN Wanlong CHEN Jiading (department of Probability and Statistics, peking university, beijing 100871, china)

In reliability tests, Type I censored data are common. For products of high quality, real life length is much longer than the censoring time. A group of items of some kind of product are put into reliability experiment. In case every item is censored,there is no failure. We refer to such data as No Failures. We construct lower confidence limits for life characteristics (such as average life, reliability, reliable span). This is done under the assumption of Weibull distribution, Lognormal distribution and nonparametric distribution family in the case of no failures.

关键词： Ordering censoring reliability.

A malware detection model based on a negative selection algorithm with penalty factor

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Science china(Information Sciences) 2010年第12期53卷 2461-2471页

作者： ZHANG PengTao 1,2 , WANG Wei 1,2 & TAN Ying 1,2 1 department of Machine Intelligence, School of Electronics Engineering and Computer Science, peking university, beijing 100871, china 2 Key Laboratory of Machine Perception, Ministry of Education, peking university, beijing 100871, china 1. department of Machine Intelligence School of Electronics Engineering and Computer Science Peking University Beijing 100871 China2. Key Laboratory of Machine Perception Ministry of Education Peking University Beijing 100871 China

A malware detection model based on a negative selection algorithm with penalty factor (NSAPF) is proposed in this paper. This model extracts a malware instruction library (MIL), containing instructions that tend to appear in malware, through deep instruction analysis with respect to instruction frequency and file frequency. From the MIL, the proposed model creates a malware candidate signature library (MCSL) and a benign program malware-like signature library (BPMSL) by splitting programs orderly into various short bit strings. Depending on whether a signature matches "self", the NSAPF further divides the MCSL into two malware detection signature libraries (MDSL1 and MDSL2), and uses these as a two-dimensional reference for detecting suspicious programs. The model classifies suspicious programs as malware and benign programs by matching values of the suspicious programs with MDSL1 and MDSL2. Introduction of a penalty factor C in the negative selection algorithm enables this model to overcome the drawback of traditional negative selection algorithms in defining the harmfulness of "self" and "nonself", and focus on the harmfulness of the code, thus greatly improving the effectiveness of the model and also enabling the model to satisfy the different requirements of users in terms of true positive and false positive rates. Experimental results confirm that the proposed model achieves a better true positive rate on completely unknown malware and a better generalization ability while keeping a low false positive rate. The model can balance and adjust the true positive and false positive rates by adjusting the penalty factor C to achieve better performance.

关键词： penalty factor negative selection algorithm signature extraction artificial immune system mal- ware detection

SYNTHESIS OF NOVEL LIQUID CRYSTALLINE POLY(METH)ACRYLATES CONTAINING SILOXANE SPACER AND TERPHENYLENE MESOGENIC UNIT

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Chinese Journal of Polymer Science 2000年第2期18卷 101-107页

作者： Zhi-qian Zang Yu-fei Luo Dong Zhang Xin-hua Wan Qi-feng Zhou department of Polymer Science & Engineering, College of Chemistry, peking university, beijing 100871, china peking Univ Coll Chem Dept Polymer Sci & Engn Beijing 100871 Peoples R China

Novel side-chain liquid-crystalline poly(meth)acrylates were synthesized using 1-(3-hydroxyl-propyl)-3-[(4.'-cyano-p-terphenyloxycarbonyl)alkyl]-1,1,3,3-tetramethyldisiloxane as the key intermediate. The polymers used a disiloxane moiety as decoupling spacer with cyano-p-terphenyl as mesogenic unit. The products were characterized by NMR, GPC, DSC and polarizing optical microscopy. All the polymers with cyano-p-terphenyl mesogens formed a stable mesophase. However, if the mesogenic unit is replaced by cyano-p-biphenyl, the liquid crystalline character will be lost. The results also showed that the decoupling is incomplete even if a complex and very flexible decoupling spacer is deliberately incorporated to obtain the highest possible decoupling effect.

关键词： liquid crystalline polymers polyacrylates 4.''-cyano-p-terphenyl

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

URBAN GROWTH, TRANSPORTATION SYSTEM AND COMMERCIALNETWORK OF beijing

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Journal of Geographical Sciences 1995年第3期5卷 15-31页

作者： Yang Wuyang(department of Geography, peking university, beijing 100871)People’s Republic of china

In this afticle, three uopt problems on the developlnent and plabong of beijing metropolis are expounded (1) Having analyzed the process of urbanlzation dunng 4. years, the autihor divides it into three Stages :city expansion, qrban sprawl and fonmation of centnpotal urban nngr. Then a rank-number-size law is pLif fotward to predict the development and allocation of satellite towns (2) Having looked back on the change of urban transpoftation nforork, the atlthor points out its merits and *** to the increases of traffic flow, improving measures for the urban road systems are demonstrated. (3) Having reviewed the llistory of commercial distnbution and referred to previous lnodels, the author roprds the spatial structure of business as a combined network from central place and idealized stnucture of lnetropolitan area. The trade and service orgaluzation in n1ain urban area and peripheral zone can be planned with defferent ways. The atlthor predicts a rational network of commerce and service of beijing with a strong BCD Which is accepted by some trade authorities

关键词： urban growth central place theory transportation system,commercial network

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Communications in Nonlinear Science and Numerical Simulation 1999年第3期4卷 186-190页

作者： Guoqian CHEN and J. H. W. LEE(Centre for Environmental Sciences, peking university, beijing 100871, china) (department of Civil Engineering, {4. of Hong Kong, Hong Kong, china) Centre for Environmental Sciences Peking University Beijing 100871 China department of Civil Engineering University of Hong Kong Hong Kong China

IntroductionThethermal,abodyofbuoyalfluidinafluidwithwhichitcanmixandgivennamebygliderpilotstothosemassesofwarmairrisingfromhotgroundwarmedbysunshineinwhichtheycansoar,***],duetoi... 详细信息

IntroductionThethermal,abodyofbuoyalfluidinafluidwithwhichitcanmixandgivennamebygliderpilotstothosemassesofwarmairrisingfromhotgroundwarmedbysunshineinwhichtheycansoar,***],duetoi...

关键词： environmental fluid mechanics thermal turbulence modeling

Choice of Optimal Trimming Proportion by the Random Weighting Method

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Acta Mathematica Sinica,English Series 1996年第3期12卷 326-336页

作者： Shi Jian Zheng Zhongguo, department of Probability and Statistics peking university beijing, 100871{4. 北京大学概率统计系北京

In this paper, a strongly consistent estimation of the optimal trimming proportion in trimmed mean is found by the random weighting method. In addition, using the same method a strongly consistent estimation for the d... 详细信息

关键词： Trimmed mean Trimming proportion Bootstrap Random weighting