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Case studies on mesoscale structures of heavy rainfall system in the Yangtze River generated by Meiyu front

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Science China Earth sciences 2005年第8期48卷 1303-1311页

作者： LIU Liping1. RUAN Zheng1.& QIN Danyu2 1. chinese{1. of Meteorological sciences, beijing 1.0081. China 2. Nanjing institute of Meteorology, Nanjing 21.044, China 1. chinese{1. of Meteorological sciences 100081 Beijing China 2. Nanjing institute of Meteorology 210044 Nanjing China

A heavy rainfall system was observed over the Yangtze River during Meiyu season by using dual-Doppler radar systems in the field experiment conducted by the project of National Fundamental Research Planning “Research on formation mechanism and the prediction theory of hazardous weather over China”. The three-dimensional mesoscale kinematic structure and process of a heavy rain on 22 and 23 July, 2002 are investigated by using the radial velocity and dual-Doppler radar technique. The results show that a southwest-northeast oriented rain band with the length of about 1.00 km involves numbers of meso-β or meso-γ-scale convective cells with the size of 20―50 km. The heavy rain band in the middle reaches of the Yangtze River ex-ists in a low-level wind shear. The interaction between southwest low-level jet on the southern side of wind shear and east wind on the northern side formed the updraft. The wind disturbance, wind shear and convergence generate the convective action. The new cell developed in right rear flank of rain band and moved to the southwest wind area, where the vapor is abundant. This kind of echo can last a long time and developed well. The strong convective echoes are often ac-companied by the meso-γ-scale vortex and convergence.

关键词： heavy rainfall in Meiyu front, mesoscale structure, dual-Doppler radar, middle reaches of the Yangtze River, low-level jet.

Effect of rock mass structure and block size on the slope stability——Physical modeling and discrete element simulation

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Science China(Technological sciences) 2005年第z1期48卷 1-17页

作者： LI Shihai1. LIAN Zhenzhong1.2 & J. G. Wang3 1. institute of Mechanics,{1., beijing 1.0080, China 2. Graduate School,{1., beijing 1.0060, China 3. Tropical Marine Science institute, National University of Singapore, Singapore 1.9260 chinese Acad Sci Inst Mech Beijing 100080 Peoples R China chinese Acad Sci Grad Sch Beijing 100060 Peoples R China Natl Univ Singapore Trop Marine Sci Inst Singapore 119260 Singapore

This paper studies the stability of jointed rock slopes by using our improved three-dimensional discrete element methods (DEM) and physical modeling. Results show that the DEM can simulate all failure modes of rock slopes with different joint configurations. The stress in each rock block is not homogeneous and blocks rotate in failure development. Failure modes depend on the configuration of joints. Toppling failure is observed for the slope with straight joints and sliding failure is observed for the slope with staged joints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering the joints in rock masses, the LEM predicts much higher factor of safety than physical modeling and DEM. The failure mode and factor of safety predicted by the DEM are in good agreement with laboratory tests for any jointed rock slope.

关键词： rock masses, slope stability, DEM simulation, block size effect, joints configuration effect, limit equilibrium method.

Application of three-dimensional discrete element face-to-face contact model with fissure water pressure to stability analysis of landslide in Panluo iron mine

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Science China(Technological sciences) 2005年第z1期48卷 146-156页

作者： ZHANG Lei1.2, WEI Zuoan1. LIU Xiaoyu1.& LI Shihai1.1.institute of Mechanics,{1., beijing 1.0080, China 2.Graduate School,{1., beijing 1.0060, China chinese Acad Sci Inst Mech Beijing 100080 Peoples R China chinese Acad Sci Grad Sch Beijing 100060 Peoples R China

Three-dimensional discrete element face-to-face contact model with fissure water pressure is established in this paper and the model is used to simulate three-stage process of landslide under fissure water pressure in the opencast mine, according to the actual state of landslide in Panluo iron mine where landslide happened in 1.90 and was fathered in 1.99. The calculation results show that fissure water pressure on the sliding surface is the main reason causing landslide and the local soft interlayer weakens the stability of slope. If the discrete element method adopts the same assumption as the limit equilibrium method, the results of two methods are in good agreement; while if the assumption is not adopted in the discrete element method, the critical φ numerically calculated is less than the one calculated by use of the limit equilibrium method for the sameC. Thus, from an engineering point of view, the result from the discrete element model simulation is safer and has more widely application since the discrete element model takes into account the effect of rock mass structures.

关键词： face-to-facecontactmodel, fissure water pressure, three-dimensional discrete element method,landslide.

Regional differences and determinants of built-up area expansion in China

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Science China Earth sciences 2007年第12期50卷 1835-1843页

作者： HUANG JiKun1.2,ZHU LiFen3,1.& DENG XiangZheng1.2 1.center for{1. Agricultural Policy,chinese academy of sciences,beijing 1.01.1.China 2 institute of Geographic sciences and Natural Resources Research,chinese academy of sciences,beijing 1.01.1.China 3 Research center of the Economy of the Upper Reaches of the Yangtze River,Chongqing Technology and Business University,Chongqing 400067,China 1. center for{1. Agricultural Policy Chinese Academy of Sciences Beijing 100101 China 2. institute of Geographic{1. and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China 3. Research center of the Economy of the Upper Reaches of the Yangtze River Chongqing Technology and Business University Chongqing 400067 China

Based on remote sensing data on land use provided by the chinese academy of sciences and socio-economic data collected by the authors,this paper analyzes the trends and regional differences in built-up area(BUA) expansion in China from the late 1.80s to 2000,and empirically estimates the major determinants of BUA expansion in different regions in 1.96―*** 1.89―2000,although China's overall BUA expansion accelerated,the trends differed significantly among *** expansion in the central and western regions accelerated significantly,but it slowed down considerably in the east-ern *** estimation results from our econometric analysis reveal that BUA expansion in the eastern region reached a period when economic growth had no further significant impact on per capita BUA,the land utilization in this region has become more intensive with further expansion of the *** the central and western regions,the BUA has expanded remarkably due to the relatively more flexible land development policies and the relatively cheap land ***,as the econ-omy continues to grow rapidly,policies relating to BUA expansion and cultivated land reductions may face more serious challenges in the central and western regions.

关键词： built-up area, land use, regional difference, determinants, China

Artificial coordinating field and its application to motion planning of robots in uncertain dynamic environments

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Science China(Technological sciences) 2004年第5期47卷 577-594页

作者： JING Xingjian1. 2, WANG Yuechao1.& TAN Dalong1.1. Robotics Laboratory, Shenyang institute of Automation,{1., Shenyang 1.001., China 2. Graduate School,{1., beijing 1.0039, China Correspondence should be addressed to Jing Xingjian 1. Robotics Laboratory Shenyang Institute of Automation Chinese Academy of Sciences 10016 Shenyang China 2. Graduate School Chinese Academy of Sciences 10039 Beijing China

Artificial coordinating fields (ACF) are proposed to deal with the motion planning problems of mobile robots in uncertain dynamic environments. An ACF around an obstacle can generate two orthogonal force vectors to a robot: one is called the coordinating force vector which is purposively designed in this paper, and the other is the repulsive force vector which is the same as that in a conventional artificial potential field. The ACF is designed according to the updated motion purpose and the relative states of the robot with respect to its local environment, and it also satisfies the robot’s dynamic constraints. The direction of the coordinating force can be determiend on line according to an optimal evaluation function. The ACF can effectively remove the local minima, and reduce the oscillation of the planned trajectory between multiple obstacles. Only local knowledge of the environments is needed in the ACF-based motion planning. The properties of the ACF such as controllability, adaptability, safety and reachability are studied and discussed in detail in this paper. Theoretical analysis and simulations are given to illustrate our main results.

关键词： artificial coordinating fields, artificial potential fields, mobile robots, motion planning, uncertain dynamic environments.

Assembly of gold nanoparticles with H_(1.)TTPR (3a, 4, 5, 8, 9, 9a, 1., 1.-octa-hydro-2H,3H-1.6,7,1.-tetrathia-perylene) as the rigid cross-linker

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chinese Science Bulletin 2004年第8期49卷 789-792页

作者： SHAO Xiangfeng1.2, WANG Tongxin1. ZHANG Deqing1. XU Wei 1.& ZHU Daoben1.1. Organic Solids Laboratory, center for Molecular{1., institute of chemistry, chinese academy of sciences, beijing 1.0080, China 2. Graduate School, chinese academy of sciences, beijing 1.0080, China Correspondence should be addressed to Zhu Daoben or Zhang Deqing (e-mail: dqzhang@***) Organic Solids Laboratory Center for Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Graduate School Chinese Academy of Sciences Beijing 100080 China

Gold nanoparticles were assembled with the rigid cross-linker, H1.TTPR. The assembly process was stud-ied with the UV-vis spectroscopy and TEM. By adjusting the amount of H1.TTPR added to the gold nanoparticle solutio... 详细信息

关键词：纳米金粒子集成刚性交叉连接 TEM UV-力光谱学

Spectrophotometric determination of cationic surfactants by formation of ternary complexes with Fe(Ⅲ) and chrome azurol S

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chinese Journal of{1. 1996年第3期14卷 228-234页

作者： SONG, Ming LIANG, Shu-Quan institute of chemistry,{1., beijing 1.0080, China institute of{1. Chinese Academy of Sciences Beijing 100080 China

An extraction-free spectrophotometric method for the determination of cationic surfactants, such as cetylpyridinium chloride, cetyltrimethylammonium bromide and zephiramine is proposed, which is based on the formation of ternary complexes with Fe(Ⅲ) and chrome azurol S. The molar ratio of the complex is 2:1.1.(Fe(Ⅲ):chrome azurol S:cationic surfactant). The method is simple, rapid and sensitive, giving an apparent molar absorptivity of 4.5×1.4 ***-1.and a linear range of 0.1.6.0 umol/L cationic surfactants. The total cationic surfactant content can be determined directly in aqueous solutions by measuring the absorbance at 680 nm (pH 5.8). The method has been successfully applied to water samples.

关键词： Cationic surfactant determination spectrophotometry ternary complex Fe(Ⅲ) chrome azurol S

Persistent anomalous flows over the subtropical western Pacific insummer

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chinese Science Bulletin 1998年第8期43卷 672-675页

作者： ZHUANG Shiyu\+1.and JI Liren\+2 1. National Meteorological Centre, China Meteorological Administration, beijing 1.0081. China 2. LASG,{1. of Atmospheric Physics, chinese academy of sciences, beijing 1.0080, China National Meteorological Ccntre China Meteomlcgical Administration Beijing China LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

The distribution of global persistent anomalies shows that the subtropical western Pacific is a key region with high_frequency occurrence of persistent anomalies. Analyses of streamfunction anomalies, OLR anomalies etc. suggest that the convective heating related to Indian monsoon might be responsible for the development of WPA. The results of numerical experiment by two linear barotropic models support the observation.

关键词： persistent anomalies subtropical high Indian monsoon anomalous forcing.

Formation of super-concentrated hydrochloric acid in the third phase in tertiary amine N235-PtCl_6^(2-)-HCl system and its influences on the Pt microemulsion extraction

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Science China chemistry 2009年第11期52卷 1825-1834页

作者： HUANG Kun1.CHEN Jing1.ZHANG ChengFeng1.2,LI ZhiHong3,PAN QingHua1.SUN Yan1.LIU ShaoXuan1.LIU XueXin2,LI WeiHong1.YANG ZhanLan1.WENG ShiFu1.HU TianDou3,XU YiZhuang1.& WU JinGuang1.1.College of chemistry and Molecular Engineering,Peking University,{1. 1.0871.China 2 institute of chemistry,chinese academy of sciences,{1. 1.01.0,China 3 institute of High Energy Physics,chinese academy of sciences,{1. 1.0049,China 1. College of chemistry and Molecular Engineering Peking University Beijing 100871 China 2. institute of chemistry Chinese Academy of Sciences Beijing 100190 China 3. institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

In this paper,we have investigated the formation of the third-phase in tertiary amine(N235)-PtCl62--HCl system and the microscopic phase structural evolution of platinum-loaded organic phases before and after the occurrence of the *** third-phase is characterized by various spectroscopic techniques,and the small angle X-ray scattering(SAXS) experiments demonstrate the appearance of nano-aggregates,i.e.,water-in-oil reversed micelles,in the third *** experimental results indicate that(1. formation of the third phase is related to the aggregation behaviors of nano-reversed micelles in which a super-concentrated hydrochloric acid formed with the H+ to H2O molar ratio being much higher than that of the conventional 37 wt% saturated hydrochloric acid.(2) The occurrence of the super-concentrated HCl results in a great amount of H+ and Cl-ions enriched and confined within the nano-water pools of W/O reversed micelles in third ***,the coordination behaviors of platinum complex ions in that super-concentrated hydrochloric acid are very different from their corresponding behaviors in bulk aqueous *** is possible that H+ ions participate in the formation of such complexes as HmPtCl6z+ in the super-concentrated hydrochloric acid.(3) The relative contents of various HmPtCl6z+ complexes are different corresponding to the H+ ion concentrations in confined nanowater *** association ability of the acidified tertiary amine N235 molecules(R3NH+) with various HmPtCl6z+ complexes plays an important role in affecting the platinum extraction behaviors.

关键词： solvent extraction third phase super-concentrated hydrochloric acid tertiary amine platinum