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Empirical likelihood-based inference in a partially linear model for longitudinal data

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Science china Mathematics 2008年第1期51卷 115-130页

作者： xue liugen~(1+) & zhu lixing~2 1 college of applied sciences, beijing university of technology, beijing 1.0022, china 2 Department of Mathematics, Hong Kong Baptist university, Hong Kong, china college of {1. sciences Beijing University of Technology Beijing China Department of Mathematics Hong Kong Baptist University Hong Kong China

A partially linear model with longitudinal data is considered, empirical likelihood to infer- ence for the regression coefficients and the baseline function is investigated, the empirical log-likelihood ratios is proven to be asymptotically chi-squared, and the corresponding confidence regions for the pa- rameters of interest are then constructed. Also by the empirical likelihood ratio functions, we can obtain the maximum empirical likelihood estimates of the regression coefficients and the baseline function, and prove the asymptotic normality. The numerical results are conducted to compare the performance of the empirical likelihood and the normal approximation-based method, and a real example is analysed.

关键词： partially linear model empirical likelihood confidence region longitudinal data 62G05 62G1. 62G20

Adjoint method for the optimum planning of industrial pollutant sources

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Science china Earth {1. 2005年第8期48卷 1270-1279页

作者： LIU Feng1.2, HU Fei2 & zhu Jiang2 1. {1. of Environmental sciences, Peking university, beijing 1.0871. china 2. LAPC, Institute of Atmospheric Physics, Chinese Academy of sciences, beijing 1.0029, china college of Environmental {1. Peking University Beijing China LAPC Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

The optimum planning of industrial pollutant sources, which optimizes the economic object without violating environmental constraints, is an important and hard task to be conquered. In this paper, an adjoint method is developed to solve the problem. The penalty function is in-troduced to deal with the environmental inequality constraints, and Lagrange function is con-structed to derive the adjoint equation and the gradient of the object function. In this means, the gradient of the object function can be calculated by solving the adjoint equation, and the infor-mation from the gradient is used to make the object function descend and approach to an optimal solution after some iterations. A two-dimensional, simplified model is used for numerical experi-ments. The theoretical derivations are verified by the results of the experiments. Furthermore, the adjoint method is shown to be of excellent convergence and efficiency, which is adaptive to the fast development of air quality numerical models and super computers.

关键词： optimum planning, industrial pollutant sources, adjoint equation, penalty function, gradient.

Size-dependent hydroxyl radicals generation induced by SiO_2 ultra-fine particles: The role of surface iron

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Science china Chemistry 2009年第7期52卷 1033-1041页

作者： SHANG Yu1. zhu Tong1. LI Yi1.2 & ZHAO JinCai3 1.{1. of Environmental sciences and Engineering, Peking university, beijing 1.0871. china 2 Chinese Academy of Meteorological sciences, beijing 1.0871. china 3 Institute of Chemistry, Chinese Academy of sciences, beijing 1.0871. china college of Environmental {1. and Engineering Peking University Beijing China Chinese Academy of Meteorological sciences Beijing China Institute of Chemistry Chinese Academy of Sciences Beijing China

Oxidative stress and hydroxyl radicals (·OH) play important roles in adverse health effects caused by inhalable ambient air particles (PM1.). The ultra-fine fraction of PM1. has been hypothesized as one of the critical contributors to ·OH generation. Both in vivo and in vitro studies have shown that ultra-fine particles (UFPs) or nano-particles generate more ·OH than larger particles with identical mass and composition. Both the surface area and surface-adsorbed redox-active metals have been suggested as factors to determine the oxidative capacity of UFPs. In this study, the ·OH-generating capability of dif-ferent sizes of SiO2 particles was investigated in order to determine which factor influences particle-induced ·OH generation. The amount of ·OH generated in both acellular and cellular systems was quantified using a capillary electrophoresis method following exposure to SiO2 particles with diameters of 1., 1.0, and 500 nm. The amount of ·OH was strongly dependent on particle size, and a significant enhancement was observed only with 1. nm particles. Further studies indicated a close association between ·OH and iron ion concentration (R2 = 0.81., p1.. Washed particles, with their surface iron being removed, did not generate ·OH. The iron-containing leachate from these washings was able to enhance ·OH production as untreated particles did. Therefore, the presence of adsorbed iron on the surface of the SiO2 particles is presented as a possible mechanism of UPFs-induced ·OH generation. The SiO2 acted as an inert substrate, and the surface of ultra-fine SiO2 particles acted as a carrier for iron.

关键词： ultra-fine particles nano-particles ·OH oxidative stress size-effect

3D building modeling,organization and application in digital city system

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中国科学：技术科学英文版 2010年第S1期53卷 134-142页

作者： YANG xue 1.WENG JingNong 1.2,XIA YuBin 2,WU Lun 3 & SUI ZhengWei 3 1.{1. of Software,Beihang university,beijing 1.01.1.china 2 {1. of Computer,Beihang university,beijing 1.01.1.china 3 Institute of Remote Sensing and GIS,Peking university,beijing 1.0871.china college of Software Beihang University Beijing China college of Computer Beihang University Beijing China Institute of Remote Sensing and GIS Peking University Beijing China

The real world is a three-dimensional(3D)space requiring that 3D geospatial information applications be developed in alignment with the observer’s visual and perceptive ***,3D building model data are required in a wide range of areas such as urban planning,environmental protection,real estate management and emergency *** the same time,the development of Web service[LU1.technologies allows the possibility of the widely distributed 3D geospatial data on the web.3D city building model with its related information is an important part in the construction of a digital city system,and has become a staple resource on the web *** view of the hierarchical representation of a 3D building model,an abstract of a 3D building model based on structure details is studied,and a novel representation approach named 3D transparent building hierarchical model is presented in this *** approach fully uses both the existing 3D modeling technologies and CAD constructing mapping *** the spatial relationship description,structural components inside a building can be represented and integrated as hierarchical models in a unified 3D *** addition,based on the characteristics of the 3D building model data,a service-oriented architecture and Web service technologies for 3D city building models are *** aim of the approach is that 3D city building models can be used as a kind of data resource service on the web,and can also exist independently in various different web applications.

关键词： 3D modeling 3D transparent building hierarchical models china Star web services

A heuristic path-estimating algorithm for large-scale real-time traffic information calculating

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Science china(Technological {1.) 2008年第S1期51卷 165-174页

作者： L WeiFeng1.zhu TongYu1.WU DongDong2,DAI Hong3 & HUANG Jian1.1.State Key Laboratory for Software Development Environment,Beihang {1.,beijing 1.0083,china 2 beijing Transportation Information Center,beijing 1.0055,china 3 college of Arts & Science,beijing Union {1.,beijing 1.0083,china State Key Laboratory for Software Development Environment Beihang University Beijing China beijing Transportation Information Center Beijing China college of Arts & Science Beijing Union University Beijing China

As the original Global Position System (GPS) data in Floating Car Data have the accuracy problem,this paper proposes a heuristic path-estimating algorithm for large-scale real-time traffic information calculating. It uses the heuristic search method,imports the restriction with geometric operation,and makes comparison between the vectors composed of the vehicular GPS points and the special road network model to search the set of vehicular traveling route candidates. Finally,it chooses the most optimal one according to weight. Experimental results indicate that the algorithm has considerable efficiency in accuracy (over 92.7%) and com-putational speed (max 8000 GPS records per second) when handling the GPS tracking data whose sampling rate is larger than 1.min even under complex road network conditions.

关键词： path-estimating floating car data (FCD) road network vector GPS

Role of gallium wetting layer in high-quality ZnO growth on sapphire (0001. substrates

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Science china(Physics,Mechanics & Astronomy) 2004年第5期47卷 612-620页

作者： ZENG Zhaoquan1,3, WANG Yong2, DU Xiaolong1, MEI Zengxia1, KONG Xianghe3, JIA Jinfeng1, xue Qikun1.& ZHANG Ze2, 4 1. State Key Laboratory for Surface Physics, Institute of Physics, Chinese Academy of sciences, beijing 100080, china 2. Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of sciences, beijing 100080, china 3. college of Physics and Engineering, Qufu Normal university, Qufu 273165, china 4. beijing university of technology, beijing 1.0022, china State Key Laboratory for Surface Physics Institute of Physics Chinese Academy of Sciences Beijing China college of Physics and Engineering Qufu Normal University Qufu China Laboratory of Electron Microscopy Institute of Physics Chinese Academy of Sciences Beijing China beijing university of technology Beijing China

A Ga wetting layer was used to modify the surface structure of sapphire (0001. substrate to prepare high-quality ZnO film by radio frequency plasma-assisted molecule beam epitaxy. We found that this Ga layer plays a crucial role in eliminating 30 rotation domains, controlling polarity and decreasing defect density in ZnO epilayers, as demonstrated by in situ reflection high energy electron diffraction, ex situ high resolution X-ray diffraction and high resolution cross-sectional transmission electron microscopy. Zn-polar film of ZnO was determined by convergent beam electron diffraction. A Ga bilayer model is proposed to understand the effects of the Ga wetting layer on high-quality ZnO growth.

关键词： Ga wetting layer, sapphire, polarity, defect density, zinc oxide, rf-MBE, RHEED, HRXRD, TEM, CBED.

Health-oriented strategies are needed to optimize china’s 2025 clean air action plan

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Science Bulletin 2024年第13期69卷 2007-2008页

作者： Tao xue Ning Kang Wei Wan Tong {1. Institute of Reproductive and Child Health/National Health Commission Key Laboratory of Reproductive Health and Department of Epidemiology and Biostatistics/Ministry of Education Key Laboratory of Epidemiology of Major Diseases(PKU) School of Public HealthPeking University Health Science CentreBeijing 100191China State Environmental Protection Key Laboratory of Atmospheric Exposure and Health Risk Management Center for Environment and HealthPeking UniversityBeijing 100871China Advanced Institute of Information technology Peking UniversityHangzhou 311215China Clean Air Asia Beijing 100600China college of Environmental {1. and Engineering Peking UniversityBeijing 100871China

Recently,china’s State Council issued the Continuous Improvement of Air Quality Action Plan(hereafter,the third action plan),which follows the Air Pollution Prevention and Control Action Plan(201.–201.)(hereafter,the first action plan)and the Three-Year Action Plan for Winning the Blue Sky Defense Battle(201.–2020)(hereafter the second action plan).The first two action plans yielded nationwide health benefits[1.3],from improving lung function[4]to saving medical expenditures[5].Based on our previous estimates[6],due to reductions in the fine particulate matter(PM2.5)level,implementation of the first and second action plans was expected to increase life expectancy by 2.1. and 3.68 months.

关键词： action hereafter nationwide

Biogas recovery from microwave heated sludge by anaerobic digestion

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Science china(Technological {1.) 2010年第1期53卷 144-149页

作者： QIAO Wei1,WANG Wei2,zhu CuiPing3 & ZHANG ZhongZhi1 1 college of Chemical Science and Engineering,china university of Petroleum,beijing 102249,china 2 Department of Environmental Science and Engineering,Tsinghua university,beijing 10084,china 3 J & K china Cleaning Energy technology Co.Ltd.,beijing 100085,china college of Chemical Science and Engineering China University of Petroleum Department of Environmental Science and Engineering Tsinghua University J & K china Cleaning Energy {1. Co. Ltd.

Biogas generated from sewage sludge,livestock waste,and food waste by anaerobic digestion is a valuable renewable energy ***,conventional anaerobic digestion is not an efficient process.A long hydraulic retention time and low biogas recovery rate hinder the applications of those *** effective pretreatment method to destroy sludge microbial cells has been one of the major concerns regarding improvement of the biogas *** article focuses on the effects of microwave heating on sludge anaerobic *** suspended solid(VSS) and chemical organic demand solubilization of heated sludge were *** heating was found to be a rapid and efficient process for releasing organic substrates from *** increase of organic dissolution ratio was not obvious when holding time was over 5 min with microwave *** effect of the VSS solubilization was primarily dependent on heating *** highest value of VSS dissolving ratio,36.4%,was obtained at 1.0°C for 30 *** COD dissolving ratio was about 25% at 1.0°*** organic carbon of treated sludge liquor was 1.98 and 2.73 g/L at 1.0°C and 1.0°C for 5 min,respectively.A biochemical methane potential(BMP) test of excess sludge and a mixture of primary and excess sludge demonstrated an increase in biogas *** total biogas from microwave treated mixture sludge increased by 1..9% to 20.2% over control after 30 days of *** production was 1..1. to 25.9% higher for excess sludge than for untreated *** VS removal ratios of mixture sludge and excess sludge were 1.% and 1.% higher,respectively,compared to the untreated sludge.

关键词： biogas recovery microwave heating sludge anaerobic digestion

Effects of chemical activation and season on birth efficiency of cloned pigs

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Science china(Life {1.) 2009年第7期52卷 657-664页

作者： MA YuFang1.2,LI Yan3,WEI HengXi1.LI QiuYan3,FANG Rui1.ZHAO Rui3,ZHANG Kun1.xue Kai1.LOU YanKun1.DAI YunPing3,LIAN LinSheng2 & LI Ning1.1.State Key Laboratory of Agrobio{1.,college of Biological sciences,china Agricultural university,beijing 1.01.3,china 2 college of Animal Science and {1.,china Agricultural university,beijing 1.01.3,china 3 beijing Genprotein Bio{1. Company,beijing 1.01.3,china State Key Laboratory of Agrobiotechnology College of Biological Sciences China Agricultural University Beijing China college of Animal Science and {1. China Agricultural University Beijing China beijing Genprotein Bio{1. Company Beijing China

The effects of chemical activation on birth efficiency of cloned pigs were studied by investigating the developmental process from porcine oocyte activation to birth of cloned *** different activation methods were used:(i) Electroporation(Ele);(ii) Ele followed by incubation with 6-dimethylaminopurine(6-DMAP);and(iii) Ele followed by a treatment with cycloheximide(CHX).In experiment 1.the rates of cleavage,developmental rates and cell number of porcine parthenogenetic(PA) embryos were investigated in the three treatment *** experiment 2,NT embryos produced by the three different activation treatments were compared for the rates of cleavage,development and cell ***,the effects of Ele and Ele+CHX activation methods on birth efficiency of cloned pigs were *** activated oocytes treated by combination activation generally showed a higher(P<0.05) blastocyst rate and produced more expanded blastocysts than oocytes activated with *** rates of cleavage and total cell number of parthenotes were not significantly *** embryos activated with 6-DMAP developed into blastocyst and expanded blastocyst stages at a significantly(P<0.05) higher rate than those treated with Ele,but the developmental capability was dramatically decreased in NT *** the CHX activation method,the NT embryo blastocyst rate was substantially(P<0.05) increased although the production of expanded blastocysts was not significantly different from that by the other two *** birth rate of cloned pigs increased in the CHX group,though the rate was not significantly different from *** effects of season on developmental rate of the porcine PA embryos and birth rate of cloned pigs were also examined in our *** oocytes collected in the spring had higher developmental capabilities than those collected in the ***,no difference in birth rate of the cloned pigs was found between the oocytes collected in the two *** re

关键词： parthenogenetic activation chemical activation nuclear transfer pig season