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Virus rejection with two model human enteric viruses in membrane bioreactor system

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Science china Chemistry 2007年第3期50卷 397-404页

作者： ZHENG Xiang1,2 & LIU JunXin1 1 Research Center for Eco-Environmental sciences, chinese academy of sciences, beijing 100085, china 2 School of Environment & Natural Resources, Renmin university of china, beijing 100872, china 1. Research Center for Eco-Environmental sciences Chinese Academy of Sciences Beijing 100085 China 2. School of Environment & Natural Resources Renmin University of China Beijing 100872 China

A membrane bioreactor (MBR) with gravity drain was tested for virus rejection with two coliphages, T4 and f2, which were used as surrogates for human enteric viruses. Virus rejection was investigated by PVDF and PP membrane modules, with the pore sizes of 0.22 and 0.1 μm, respectively. In tap water system, 2.1 lg rejection of coliphage T4 could be achieved by PVDF membrane compared with complete rejection by PP membrane, while for coliphage f2 with smaller diameter, 0.3―0.5 lg rejection of the influent virus was removed by the two membranes. In domestic wastewater system, cake layer and gel layer on the membrane surface changed the cut-off size of the membrane so that there was no significant difference between PP and PVDF for each coliphage. The removal ratios of coliphage T4 and f2 in the MBR were more than 5.5 and 3.0 lg, respectively. Compared with 5.5 lg removal for virus T4 in the MBR system, only 2.1 lg (96.8%―99.9%) removal rate was observed in the conventional activated sludge system with the influent virus concentration fluctuating from 1830 to 57000 PFU/mL. Only 0.8%―22% virus removal was the effect of adsorption to activated sludge, which showed a decreasing tendency with the retention time, while 75%―98% was the effect of virus inactivation by microbial activity. It indicated that the major mechanism of virus removal was not the transfer of viruses from the water phase to the sludge phase but inactivation in the biological treatment process.

关键词： MBR model virus enteric virus inactivation

An Efficient High-Resolution Shock-Capturing Scheme for Multi-Dimensional Flows I. Hydrodynamics

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chinese Journal of Astronomy and Astrophysics 2006年第6期6卷 680-688页

作者： Cong Yu National Astronomical Observatories / Yunnan Astronomical Observatory, chinese academy of sciences, Kunming 650011 graduate School of chinese academy of sciences, beijing 10004. graduate School of chinese academy of sciences Beijing 100049

Many problems at the forefront of theoretical astrophysics require a treatment of dynamical fluid behavior. We present an efficient high-resolution shock-capturing hydrodynamic scheme designed to study such phenomena. We have implemented a weighted, essentially non-oscillatory （WENO） scheme to fifth order accuracy in space, lILLE approximate Riemann solver is used for the flux computation at cell interface, which does not require spectral decomposition into characteristic waves and so is computationally friendly. For time integration we apply a third order total variation diminishing （TVD） Runge-Kutta scheme. Extensive testing and comparison with schemes that *** characteristic decomposition are carried out demonstrating the ability of our scheme to address challenging open questions in astrophysics.

关键词： accretion - hydrodynamics- method numerical - shock waves

Relationship between precipitation and the infiltration depth over the middle and lower reaches of the Yellow River and Yangtze-Huaihe River Valley

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Progress in Natural Science:Materials International 2008年第9期18卷 1123-1128页

作者： Zhixin Hao a, Jingyun Zheng a, Quansheng Gea,, Xifeng Guoa,b a Institute of Geographical sciences and Natural Resources Research, chinese academy of sciences, 11A, Datun Road Anwai, Chaoyang District, beijing 100101, china b graduate university of chinese academy of sciences, beijing 10004., china Institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences 11A Datun Road Anwai Chaoyang District Beijing 100101 China graduate university of chinese academy of sciences Beijing 100049 China

The purpose of the paper is to extract and make the best use of rainfall information contained in the chinese historical archives of Qing Dynasty, and reconstruct the precipitation series during *** study followed the Yu-Fen-Cun (rainfall infiltration depth) observation method in Qing Dynasty, to conduct soil infiltration experiment under the natural rainfall conditions during *** related parameters, such as precipitation, intensity, initial soil moisture content and infiltration depth have been measured at 10 stations (east of 105°E, 30°-40°N) with representative climatic conditions and soil physical texture in the middle and lower reaches of the Yellow River and Yangtze-Huaihe River *** statistical results indicate that precipitation is the primary infiuencing factor to infiltration depth and is positively correlated with the infiltration ***, the efiects of every factor on infiltration depth are significantly difierent between the middle and lower reaches of the Yellow River and Yangtze-Huaihe River ***, the relationship equations of precipitation and infiltration depth are established for each site, most of which can pass over 60% of the variance explanations and provide quantitative models to reconstruct the precipitation series using Yu-Fen-Cun records in Qing Dynasty.

关键词： Middle and lower reaches of the Yellow River and Yangtze-Huaihe River Valley Precipitation Infiltration depth Yu-Fen-Cun Climate reconstruction

Convergence of the Vlasov-Poisson-Fokker-Planck system to the incompressible Euler equations

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Science china Mathematics 2006年第2期49卷 255-266页

作者： XIAO Ling, LI Fucai & WANG Shu academy of Mathematics and Systems Science, chinese academy of sciences, beijing 100080, china Department of Mathematics, Nanjing university, Nanjing 210093, china College of Applied sciences, beijing university of Technology, beijing 100022, china 1. academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China 2. Department of Mathematics Nanjing University Nanjing 210093 China 3. College of Applied sciences Beijing University of Technology Beijing 100022 China

We establish the convergence of the Vlasov-Poisson-Fokker-Planck system to the incompressible Euler equations in this paper. The convergence is rigorously proved on the time interval where the smooth solution to the incompressible Euler equations exists. The proof relies on the compactness argument and the so-called relative-entropy method.

关键词： Vlasov-Poisson-Fokker-Planck system incompressible Euler equations relative-entropy method.

De-interlacing technique based on total variation with spatial-temporal smoothness constraint

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Science in china(Series F) 2007年第4期50卷 561-575页

作者： YIN XueMin1,2,3, YUAN JianHua1,2, LU XiaoPeng1,2 & ZOU MouYan1,2 1 Institute of Electronics, chinese academy of sciences, beijing 100080, china 2 graduate School, chinese academy of sciences, beijing 100039, china 3 Jiuquan Satellite Launch Center, Lanzhou 732750, china 1. Institute of Electronics Chinese Academy of Sciences Beijing 100080 China 2. graduate School Chinese Academy of Sciences Beijing 100039 China 3. Jiuquan Satellite Launch Center Lanzhou 732750 China

This paper introduces a new method of converting interlaced video to a progressively scanned video and image, The new method is derived from Bayesian framework with the spatial-temporal smoothness constraint and the MAP is done by minimizing the energy functional, The half-quadratic regularization method is used to solve the corresponding partial differential equations （PDEs）, This approach gives the improved results over the conventional de-interlacing methods, Two criteria are proposed in the paper, and they can be used to evaluate the performance of the de-interlacing algorithms,

关键词： video processing de-interlacing total variation spatio-temporai smoothness constraint PDEs half-quadratic regularization

On designated-weight Boolean functions with highest algebraic immunity

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Science china Mathematics 2010年第11期53卷 2847-2854页

作者： LIU MeiCheng1,3, DU YuSong2, PEI DingYi2 & LIN DongDai1 1The State Key Laboratory of Information Security, Institute of Software of chinese academy of sciences, beijing 100190, china 2College of Mathematics and Information sciences, Guangzhou university, Guangzhou 510006, china 3graduate university of chinese academy of sciences, beijing 10004., china 1. The State Key Laboratory of Information Security Institute of Software of Chinese Academy of Sciences Beijing 100190 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China2. College of Mathematics and Information Sciences Guangzhou University Guangzhou 510006 China

Algebraic immunity has been considered as one of cryptographically significant properties for Boolean functions. In this paper, we study ∑d-1 i=0 (ni)-weight Boolean functions with algebraic immunity achiev-ing the minimum of d and n - d + 1, which is highest for the functions. We present a simpler sufficient and necessary condition for these functions to achieve highest algebraic immunity. In addition, we prove that their algebraic degrees are not less than the maximum of d and n - d + 1, and for d = n1 +2 their nonlinearities equalthe minimum of ∑d-1 i=0 (ni) and ∑ d-1 i=0 (ni). Lastly, we identify two classes of such functions, one having algebraic degree of n or n-1.

关键词： cryptography Boolean function algebraic immunity algebraic degree nonlinearity

Vertical adaptive radiation in ocean Prochlorococcus:Evolutionary implications of the Ch1 b/a ratio from molecular evidence

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Progress in Natural Science:Materials International 2009年第11期19卷 1561-1568页

作者： Song Qin~(a,*),Yinchu Wang~(a,b) a Yantai Institute of Coastal Zone Research for Sustainable Development,chinese academy of sciences,Yantai 264003,china b graduate university of chinese academy of sciences,beijing 10004.,china [a]Yantai Institute of Coastal Zone Research for Sustainable Development Chinese Academy of Sciences Yantai 264003 China [b]graduate university of chinese academy of sciences Beijing 100049 China

Prochlorococcus is a marine cyanobacterium of global *** ecotypes are adapted to either high-light(HL) or low-light (LL) *** ratio between chlorophyll(Chl) a and b is a distinguishing characteristic of these two ***,how this ratio evolved in Prochlorococcus during this ecotype differentiation remains *** analyses reveal that the ancestor of Prochlorococcus was typically low-light *** LL ecotype showed a stagnant evolution,and the HL ecotype was recently *** was an adaptive radiation after directional evolution in the Chl bla ratio *** in chlorophyllide a oxygenase(CAO) and positive selection on Clp protease contributed to the directional evolution of *** recombinant fragments of CAO were correlated with a large group of shared coevolving *** of positive selection was found in both subunits of *** bla ratio evolution,as annotated by molecular evidence,appears to be among the crucial reasons that explain how Prochlorococcus has become the dominant photosynthetic organism in the ocean.

关键词： Prochlorococcus Ch1 b/a ratio Adaptive evolution Trait evolution Ecotype differentiation

Evolutionary pattern of the regulatory network for flower development:Insights gained from a comparison of two Arabidopsis species

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Journal of Systematics and Evolution 2011年第6期49卷 528-538页

作者： 1,2 Yang LIU 1,2Chun-Ce GUO 1Gui-Xia XU 1Hong-Yan SHAN 1Hong-Zhi KONG 1(State Key Laboratory of Systematic and Evolutionary Botany,Institute of Botany,chinese academy of sciences,beijing 100093,china) 2(graduate university of chinese academy of sciences,beijing 10004.,china) (State Key Laboratory of Systematic and Evolutionary Botany Institute of Botany Chinese Academy of Sciences Beijing 100093 China) (graduate university of chinese academy of sciences Beijing 100049 China) *Correspondence: Hong-Zhi KONG *Correspondence: E-mail: hzkong@*** Tel.: 86-10-62836489 Fax: 86-10-62590843.

Previous studies on Arabidopsis thaliana and other model plants have indicated that the development of a flower is controlled by a regulatory network composed of genes and the interactions among *** on the evolution of this network will therefore help understand the genetic basis that underlies flower *** this study,by reviewing the most recent published work,we added 31 genes into the previously proposed regulatory network for flower ***,the number of genes reached *** then compared the composition,structure,and evolutionary rate of these genes between *** and one of its allies,*** found that two genes(FLC and MAF2)show 1:2 and 2:2 relationships between the two species,suggesting that they have experienced independent,post-speciation *** the remaining 58 genes,35(60.3%)have diverged in exon-intron structure and,consequently,code for proteins with different sequence features and *** evolutionary analyses further revealed that,although most floral genes have evolved under strong purifying selection,some have evolved under relaxed or changed constraints,as evidenced by the elevation of nonsynonymous substitution rates and/or the presence of positively selected *** together,these results suggest that the regulatory network for flower development has evolved rather rapidly,with changes in the composition,structure,and functional constraint of genes,as well as the interactions among them,being the most important contributors.

关键词： Arabidopsis evolution flower development regulatory network.

Assessment of soil erosion and sediment delivery ratio using remote sensing and GIS:a case study of upstream Chaobaihe River catchment, north china

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International Journal of Sediment Research 2008年第2期23卷 167-173页

作者： Weifeng ZHOU1 and Bingfang WU2 1 Doctor candidate,graduate School of the chinese academy of sciences(CAS),beijing 100039,china 2 Prof.,Institute of Remote Sensing Applications,chinese academy of sciences(CAS),beijing 100101,china [a]Doctor candidate graduate School of the chinese academy of sciences(CAS) beijing 100039 china [b]Prof. Institute of Remote Sensing Applications chinese academy of sciences(CAS) beijing 100101 china

Soil erosion in catchment areas reduces soil productivity and causes a loss of reservoir *** parametric models have been developed to predict soil erosion at drainage basins,hill slopes and field *** well-known Universal Soil Loss Equation(USLE) represents a standardized *** reservoir,which sits on Chaobaihe River,is the main surface source of drinking water for beijing,the capital of *** and soil loss are the main reasons for sediment to enter a *** yield is assessed using a version of the universal soil loss equation modified by chinese *** year 2001 and 2002 data for factors in the equation are obtained from remote sensing or collected to form an analysis *** factors are computed and mapped using Geographic Information System *** on the complex database,the modified model is *** pixel-based computing the sediment yield per hydrological unit is *** model does not consider sediment deposition occurring on *** soil loss is often higher than the sum of those measured at catchment *** sediment delivery ratio(SDR) per hydrological unit is also *** study analyzes the main contributions of sediment yields on sub-basins of the Chaobaihe River to the Miyun Reservoir,and discusses the possible reasons for the difference between SDRs in 2001 and 2002 at different *** result shows that in the upper basin of the Miyun Reservoir,in 2001 the area of erosion that could be neglected was 8,202.76 km2,the area of low erosion 3,269.59 km2,the area of moderate erosion 3,400.97 km2,the area of high erosion 436.89 km2,the area of strong erosion 52.19 km2 and the area of severe erosion 3.13 *** highest soil loss was 70,353 t/*** in Fengning County in 2001,followed by 64,418 t/*** by Chicheng County in *** SDR in 2002 was lower than that in *** main reasons are the decreasing rainfall erosivity and total runoff.

关键词： Modified USLE Gross erosion Sediment delivery ratio