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Macroscopic relationship for preferential flow in the vadose zone:Theory and validation

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Science china(Technological Sciences) 2009年第11期52卷 3264-3269页

作者： LIU HuiHai1 & ZHANG RenDuo2 1 Earth Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 947200, USA 2 School of Environmental Science and Engineering, sun yat-sen university, guangzhou 510275, china Earth Science Division Lawrence Berkeley National Laboratory Berkeley CA 947200 USA School of Environmental Science and Engineering Sun Yat-sen University Guangzhou 510275 China

Preferential flow commonly observed in unsaturated soils allows rapid movement of solute from the ground surface or vadose zone to the groundwater, bypassing a significant volume of unsaturated soil and increasing the risk of groundwater contamination. A variety of evidence indicates that complex preferential flow patterns observed from fields are fractals. This paper discusses a macroscopic relationship for modeling preferential flow in the vadose zone. Conceptually, the flow domain can be divided into active and inactive regions. Flow occurs preferentially in the active region (characterized by fractals), and inactive region is simply bypassed. The portion of the active region was found to be a power function of saturation. The validity of this macroscopic relationship is demonstrated by its consistency with field observations and the related numerical experiments.

关键词： preferential flow constitutive relations vadose zone hydrology

Fast Fourier-Galerkin methods for first-kind logarithmic-kernel integral equations on open arcs

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Science china mathematics 2010年第1期53卷 1-22页

作者： WANG Bo1,WANG Rui2 & XU YueSheng3,4,1Academy of mathematics and Systems Science,Chinese Academy of Sciences,Beijing 100190,china 2School of Information Science and Engineering,Graduate university of the Chinese Academy of Sciences,Beijing 100190,china 3department of mathematics,Syracuse university,Syracuse,NY 13244,USA 4department of Scientific Computing and Computer Applications,sun yat-sen university,guangzhou 510275,china 1. Academy of mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China2. School of Information Science and Engineering Graduate University of the Chinese Academy of Sciences Beijing 100190 China3. Department of Mathematics Syracuse University Syracuse NY 13244 USA4. Department of Scientific Computing and Computer Applications Sun Yat-sen University Guangzhou 510275 China

We propose a fully discrete fast Fourier-Galerkin method for solving an integral equation of the first kind with a logarithmic kernel on a smooth open arc,which is a reformulation of the Dirichlet problem of the Laplace equation in the *** optimal convergence order and quasi-linear complexity order of the proposed method are established.A precondition is *** this method with an efficient numerical integration algorithm for computing the single-layer potential defined on an open arc,we obtain the solution of the Dirichlet problem on a smooth open arc in the *** examples are presented to confirm the theoretical estimates and to demonstrate the efficiency and accuracy of the proposed method.

关键词： Dirichlet problem open arc singular boundary integral equations Fourier-Galerkin methods logarithmic potentials

^(40)Ar/^(39)Ar chronology and geochemistry of high-K volcanic rocks in the Mangkang basin, Tibet

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Science china Earth Sciences 2005年第1期48卷 1-12页

作者： ZHANG Huihua, HE Huaiyu, WANG Jianghai & XIE Guanghong guangzhou Institute of Geochemistry, Chinese Academy of Sciences, guangzhou 510640, china Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, china College of Life Sciences, sun yat-sen university, guangzhou 510275, china 1. Chinese Academy of Sciences Guangzhou Institute of Geochemistry 510640 Guangzhou China 2. Chinese Academy of Sciences Institute of Geology and Geophysics 100029 Beijing China 3. College of Life Sciences Sun Yat-Sen University 510275 Guangzhou China

Our two newly obtained high-quality 40Ar/39Ar ages suggest that the high-K volcanic rocks of the Lawuxiang Formation in the Mangkang basin, Tibet were formed at 33.5 ( 0.2 Ma. The tracing of elemental and Pb-Sr-Nd isotopic geochemistry indicates that they were derived from an EM2 enriched mantle in continental subduction caused by transpression. Their evidently negative anomalies in HFSEs such as Nb and Ta make clear that there is an input of continental material into the mantle source. The high-K rocks at 33.5 ( 0.2 Ma in the Mangkang basin may temporally, spatially and compositionally compare with the early one of two-pulse high-K rocks in eastern Tibet distinguished by Wang J. H. Et al., implying that they were formed in the same tectonic setting.

关键词： Cenozoic high-K volcanic rocks, 40Ar/39Ar chronology, Mangkang basin, Tibet.

Characterization of static bifurcations for n-dimensional flows in the frequency domain

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Control Theory and Technology 2006年第3期4卷 217-222页

作者： Li ZENG, Yi ZHAO (department of mathematics, sun yat-sen university, guangzhou Guangdong 510275, china School of Informatics, Guangdong university of Foreign Studies, guangzhou Guangdong 510006, china department of mathematics, sun yat-sen university, guangzhou Guangdong 510275, china) department of mathematics Sun Yat-Sen University Guangzhou Guangdong 510275 China School of Informatics Guangdong University of Foreign Studies Guangzhou Guangdong 510006 China

In this paper n-dimensional flows (described by continuous-time system) with static bifurcations are considered with the aim of classification of different elementary bifurcations using the frequency domain formalism. Based on frequency domain approach, we prove some criterions for the saddle-node bifurcation, transcritical bifurcation and pitchfork bifurcation, and give an example to illustrate the efficiency of the result obtained.

关键词： Static bifurcation Frequency domain approach Saddle-node bifurcation Transcritical bifurcation Pitchfork bifurcation

Effects　of　He－Ne　laser　irradiation　at　acupuncture　points　on　steroid　hormone　receptors　of　uteri　in　rabbits

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Chinese Journal of Lasers 1994年第4期B3卷 369-375页

作者： HUANG Ping CAI Shangda QIU Yiguang HUANG Wenxin (department of Biology, department of Biochemistry,sun yat-sen university of Medical Sciences, guangzhou 510089, china) Zhongshan Univ of Medical Sciences Guangzhou China

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关键词： He-Ne laser acupoint hormone receptor

Study on the SiN_x/Al rear reflectance performance of crystalline silicon solar cells

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Science china(Technological Sciences) 2010年第12期53卷 3209-3213页

作者： LIANG ZongCun, CHEN DaMing, ZHU YanBin & SHEN Hui Institute for Solar Energy Systems, State Key Laboratory of Optoelectronic Materials and Technologies, sun yat-sen university, guangzhou 510275, china 1. Institute for Solar Energy Systems State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-Sen University Guangzhou 510275 China

The performance of internal rear surface reflectance of crystalline silicon solar cells is becoming more and more important with the decrease of thickness of the silicon wafers. In this paper PC1D was used to simulate the correlations between the rear surface reflectance and the electrical as well as optical properties of the solar cells. The results showed that the short circuit current, open circuit voltage and quantum efficiency were all enhanced with the increase of the rear reflectance. When the rear reflectance increased from 60% to 100%, the short circuit current, open circuit voltage and maximum output power were improved by about 0.128 A, 0.007 V, and 0.066 W, respectively. The internal quantum efficiency was improved by 39.9%, the external quantum increased by 17.4%, and the efficiency of the solar cells was enhanced by 0.4% at 1100 nm wavelength. The screen-printing was selected to prepare SiNx/Al reflector, and experimental results showed that the SiNx/Al reflector has desired characteristic of internal rear reflectance, with the reflectivity of 15% higher than that of conventional aluminum BSF at 1100 nm wavelength.

关键词： crystalline silicon solar cells rear reflectance PC1D simulation rear reflector

New dragonflies (Insecta: Odonata: Gomphaeschnidae) from the Yixian Formation in Inner Mongolia, china

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Progress in Natural Science:Materials International 2008年第1期18卷 59-64页

作者： Binglan Zhang a ,Dong Rena ,*,Hong Pang b aCollege of Life Science,Capital Normal university,Beijing 100037,china bState Key Laboratory of Biocontrol and Institute of Entomology,sun yat-sen university,guangzhou 510275,china College of Life Science Capital Normal University Beijing 100037 China State Key Laboratory of Biocontrol and Institute of Entomology Sun Yat-sen University Guangzhou 510275 China

Two fossil dragonflies from the Upper Jurassic to Lower Cretaceous Yixian Formation in Liutiaogou Village,Ningcheng County, Inner Mongolia,china are described and *** are assigned to two new genera and species,i.e.,Sophoaeschna frigida gen. et *** Falsisophoaeschna generalis *** *** the family Gomphaeschnidae Tillyard&Fraser,*** is the first report of Odonata from Yixian Formation in Inner Mongolia and the second record of fossil Gomphaeschnidae from china.

关键词： Odonata New genus Upper Jurassic to Lower Cretaceous Yixian Formation china

Planning Environmental Impact Assessment Orienting Sustainable Development: Opportunities and Challenges

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Chinese Journal of Population,Resources and Environment 2005年第4期3卷 33-39页

作者： sun Yanjun 1, Chen Xingeng 1, Bao Yun 2, Peng Xiaochun 3 & Gao Changbo 1 1.School of Environmental Science and Engineering, sun yat-sen university, guangzhou 510275, china 2. Research Center for Coastal Ocean Science and Technology, sun yat-sen university, guangzhou 510275, china 3. South china Institute of Environmental Science, SEPA, guangzhou 510655, china

Strategic Environmental Assessment is a frontier subject in the field of Environmental Impact Assessment. In the past two decades, especially in recent years, much more importance has been attached to Strategic Environmental Assessment. The Environmental Impact Assessment Law of the P.R. china which was promulgated provides a great opportunity for the development of Planning Environmental Impact Assessment and brings great challenges for the development of traditional Project Environmental Impact Assessment and Planning Environmental Impact Assessment at the same time. In order to promote the implementation of "The EIA Law", the inherent limitations of Project Environmental Impact Assessment must be identified sufficiently and the theory research and practice of Planning Environmental Impact Assessment should be strengthened as well. Measures should be taken currently to enforce the operation system. The authors wish to offer a few references to the progress and implementation of Planning Environmental Impact Assessment in china.

关键词： planning environmental impact assessment strategic environmental assessment sustainable development opportunities challenges.

Ecdysteroids in the adults and eggs of Opogona sacchari (Bojer),an invasive alien pest

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Science china(Life Sciences) 2008年第2期51卷 140-144页

作者： WANG FangHai, ZHANG GuRen, WEN RuiZhen & HE GuoFeng State Key Laboratory for Biological Control and Institute of Entomology, sun yat-sen university, guangzhou 510275, china 1. State Key Laboratory for Biological Control and Institute of Entomology Sun Yat-sen University Guangzhou 510275 China

In order to understand the composition and quantitative variation of ecdysteriods in the adults and eggs of Opogona sacchari (Bojer), an invasive alien pest, we analyzed the ecdysteroid composition and titers in the adult and egg of this pest. On day 4 after eclosion, the titer of ecdysteriods in the male adult was 0.080 ng/adult, much lower than 5.978 ng/adult in the female adult. During the development of ovaries, the titer of ecdysteriods was low on the first two days, and high in the late period, with the peak (10.48 ng/ovary) appearing on day 3. During the development of eggs, the titer of ecdysteriods was about 0.010 ng/egg from day 1 to day 3, and then decreased to 0.006 ng/egg on day 4. In both adults and eggs, three main components of ecdysteriods were found by identification of HPLC/RIA. They were 20-hydroxyecdysone, 26-hydroxyecdysone, and an unidentified component.

关键词： Opogona sacchari ecdysteroids adults eggs