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EXPERIMENTAL STUDY ON THE VORTEX FORMATION AND ENTRAINMENT CHARACTERISTICS FOR A ROUND TRANSVERSE JET IN SHALLOW WATER

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Journal of Hydrodynamics 2009年第3期21卷 386-393页

作者： FAN Jing-yu ZHANG Yan WANG Dao-zeng shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China Key Laboratory of Advanced Display and System Applications Ministry of Education and SMIT Center School of Mechatronics Engineering and Automation Shanghai University Shanghai 200072 China

The vortex formation and entrainment characteristics for a round transverse jet in shallow water were experimentally investigated by means of a combination of LIF flow visualization and PIV measurement. A scarf vortex wrapped around the main body of the jet is formed in the near-wall region due to the interaction between the resulting wall jet and sufficiently shallow crossflow, with some more or less unsteady flow properties and with spreading ranges as functions of both the velocity ratio and the water depth within the near field. The entrainment of the ambient crossflow fluid into the jet main body is closely associated with the time-evolving features of the shear layer between the jet and surrounding fluid as well as the induced vortical structures near the wall. In the case of slight impingement upon the wall, the interaction between the jet shear layer and the weak, unstable scarf vortex gives rise to an appreciable local entrainment enhancement, confined in the near-wall region in the vicinity of the stagnation point. While in the case of intense impingement upon the wall, the well-organized and stable scarf vortex gives rise to a greatly enhanced entrainment and a greatly increased lateral spreading rate nearly throughout the overall near field as compared to the conventional wall jet. In addition, the entrainment of the ambient crossflow fluid by the scarf vortex in this case occurs largely on the surface of the unique spiral roller structure by itself due to the presence of smaller and unorganized eddies, and accordingly the scarf vortex is likely to keep its spiral roller structure steadily to a relatively great downstream distance within the near field.

关键词： transverse jet shallow water vortex formation entrainment PIV measurement

Phosphate removal and recovery through crystallization of hydroxyapatite using xonotlite as seed crystal

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Journal of Environmental sciences 2009年第5期21卷 575-580页

作者： CHEN Xuechu, KONG Hainan, WU Deyi, WANG Xinze, LIN Yongyong school of Environmental science and engineering, shanghai Jiao Tong university, shanghai 200240, china school of Environmental science and engineering Shanghai Jiao Tong University Shanghai 200240 China

Xonotlite was synthesized and tested for phosphate removal and recovery from synthetic solution in a batch mode. The effects of pH, initial calcium concentration, bicarbonate concentration on phosphate removal through crystallization were examined. The morphology and X-ray diffraction （XRD） pattern of xonotlite before and after crystallization confirmed the formation of crystalline hydroxyapatite. The results indicated that the crystallization product had a very high P content （〉 10%）, which is comparable to phosphate rock at the dosage of 50-200 mg xonotlite per liter, with a maximum P content of 16.7%. The kinetics of phosphate removal followed the second-order reaction equation. The phosphate removal ability increased with increasing pH. The precipitation of calcium phosphate took place when pH was higher than 7.2, whereas the crystallization occurred at pH 6.0. A high calcium concentration could promote the removal of phosphate via crystallization, while a high bicarbonate concentration also enhanced phosphate removal, through that the pH was increased and thus induced the precipitation process. When xonotlite was used to remove phosphate from wastewater, the removal efficiency could reach 91.3% after 24 h reaction, with removal capacity 137 mg/g. The results indicated that xonotlite might be used as an effective crystal seed for the removal and recovery of phosphate from aqueous solution.

关键词： phosphate recovery crystallization xonotlite

New Receiving Mode of Extinction for Determining Particle Size and Density without Convex Lens

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Chinese Journal of Lasers 2002年第1期11卷 46-51页

作者： WU Weiliang CHEN Hanping (school of Power and Energy engineering, shanghai Jiao Tong university, shanghai 200030, china) CAI Xiaoshu WANG Naining (school of Power and Energy engineering, university of shanghai for science and Technology, shanghai 2 school of Power and Energy engineering Shanghai Jiao Tong University 上海 200030 school of Power and Energy engineering University of Shanghai for Science and Technology 上海 200093

In this article a new receiving mode for scattering light by particle is theoretically discussed. Using this receiving mode the convex lens can be omitted during determining the extinction of particle. Therefore the extinction coefficient of sphere particles is redefined by extrapolating the conventional one. In terms of the calculation results of light scattering the definition of near-field extinction coefficient of a swarm particle is depicted. Through the error analysis it is proved that the error coming from the new definition of extinction coefficient is acceptable for engineering application. In addition, a technique for determining the particle size and density is presented in this article and the advantage using this receiving mode is described.

关键词： extinction of particle light scattering fluctuation method particle size particle density

Tribological problems of surface IC processed MEMS

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science china Mathematics 2001年第S1期44卷 443-448页

作者： CHEN Xiaoyang SHEN Xuejin LU Jingtang school of Mechatronical engineering and Automation, shanghai university, shanghai 200072, china shanghai Univ Sch Mechatron Engn & Automat Shanghai 200072 Peoples R China

Successful microactuators of simple mechanics on silicon chip are a prerequisite formonolithic microrobotic systems. Recent development in microelectromechanical systems (MEMS)has led to the success in building new types of microactuators. Based on the design of microgrip-pers and linear microvibromotor, which were fabricated using surface micromachining, the analysisof contact pairs and opposite movement forming of moving elements is given in this paper. Thesource and mechanism of tribology of MEMS are discussed. Associated with the developing his-tory of macro-machine, several research methods and possible existing problems about the tribol-ogy of surface IC processed MEMS are pointed out.

关键词： MEMS surface micromachining tribology silicon

A NEW CONTINUUM TRAFFIC MODEL WITH THE EFFECT OF VISCOSITY

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Journal of Hydrodynamics 2011年第2期23卷 164-169页

作者： SONG Tao LI Xing-li KUANG Hua DONG Li-yun shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University Shanghai 200072 China school of Applied science Taiyuan University of Science and Technology Taiyuan 030024 China College of Physics and Technology Guangxi Normal University Guilin 541004 China

Through considering the connection between microscopic car-following model and macroscopic continuum model, a new viscous vehicular flow model is proposed, in which the viscosity coefficient is determined by a more realistic constitutive relationship between averaged reaction time of drivers and the car density. Further analysis indicates that two traffic sound speeds in this viscous model may determine the existence and the stability of traveling wave solutions with an analytical method.

关键词： viscosity continuum traffic model reaction time traffic sound speed traveling wave

Physical Simulation of Nonmetallic Particle Movement in Al Melt under Electromagnetic Field

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Journal of Materials science & Technology 2001年第4期17卷 463-465页

作者： Tianxiao LI, Zhenming XU,Baode SUN,Da SHU and Yaohe ZHOU school of Materials science and engineering, shanghai Jiaotong university, shanghai 200030, china Sch. of Mat. Sci. and Eng. Shanghai Jiaotong Univ. Shanghai 200030 China

Physical simulation is used to study the movement of nonmetallic particles in Al melt in electro- magnetic field. It is found that the terminal velocity of particles in different Reynolds number range has different functions. By confirming drag force coefficient of nonmetallic particles with Reynolds number in the range of 0.2-10 and 10-25 respectively, two functions of terminal ve- locity for spherical nonmetallic particles have been got accordingly, which provide a theoretical basis for separating nonmetallic inclusions from Al melt in electromagnetic field.

关键词： Al Physical Simulation of Nonmetallic Particle Movement in Al Melt under Electromagnetic Field Simulation

An improved approach to the efficient construction of and search operations in motion graphs

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science china(Information sciences) 2012年第5期55卷 1042-1051页

作者： GAO Yan 1,CHEN ZhiHua 2,CHEN MinGang 3 & SHEN Yang 3 1 Software engineering Institute,East china Normal university,shanghai 200062,china 2 Department of computer science and engineering,East china university of science and Technology,shanghai 200237,china 3 Department of computer science and engineering,shanghai Jiao Tong university,shanghai 200240,china Software engineering Institute East China Normal University Shanghai China Department of computer science and engineering East China University of Science and Technology Shanghai China Department of computer science and engineering Shanghai Jiao Tong University Shanghai China

Motion graphs have been widely used as an effective technique in the synthesis of human *** synthesize well-formed motions,motion graphs require smooth transitions and good ***,the time and costs grow quadratically as the graph size *** this paper,we present a method to set up a hierarchical structure,called a structure *** coarse level of this graph models different motion categories and their transitions,and the fine level mainly captures different motion *** interpolation space method is used to improve the graph connectivity at the fine *** structure guides the establishment of a faster and more realistic graphical *** the building process,this structure also helps with searching the motion graph,by performing a traverse search and placing the findings into a direct look-up table or local search ***,when there is no direct link between the different motions,a navigation map is introduced to conduct an appropriate search path via a series of transition motion *** experimental results indicate that our approach could lower the computation time in construction and searching,while simultaneously providing a richer variety of motion styles.

关键词： motion graph structure table registration curve motion interpolation

Identity based signature scheme based on cubic residues

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science china(Information sciences) 2011年第10期54卷 2001-2012页

作者： XING DongSheng,CAO ZhenFu & DONG XiaoLei Department of computer science and engineering,shanghai Jiao Tong university,shanghai 200240,china Department of computer science and engineering Shanghai Jiao Tong University Shanghai China

We propose a novel method to compute a cubic root of a cubic residue in Eisenstein *** applying our method,a new identity based signature scheme is proposed based on cubic *** formally prove that our scheme is secure against existential forgery on the adaptive chosen message and identity attacks assuming the hardness of *** scheme is the first identity based signature scheme based on cubic residues.

关键词： Eisenstein ring identity based signature cubic residue factoring random oracle proven security

SEM in-situ Fracture Observation and the Reinforcing Effect of Composite SiC_p/ZA22

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Journal of Materials science & Technology 2001年第6期17卷 649-652页

作者： Jun WANG, Baode SUN and Yaohe ZHOU school of Materials science and engineering, shanghai Jiaotong university, shanghai 200030, china Lining ZHANG and Feng CHEN Department of Materials science and engineering, Southeast university, Dept. of Mat. Sci. and Eng. Southeast Univ. Nanjing 210096 China

The strengthening effect of a Zn alloy reinforced by SiC particulate was examined. Based on the results of SEM in-situ fracture observation and stress field analysis by finite element method, it is believed that the r... 详细信息

关键词： SiC SEM in-situ Fracture Observation and the Reinforcing Effect of Composite SiC_p/ZA22